SXTE-J / DP Software Version 2.02 Prepared by M.Morrison Main Body Modified: 4-Aug-89 Appendix A Modified: 16-Dec-89 Appendix B Modified: 22-Nov-89 Appendix C Modified: 22-Nov-89 Table of Contents Page 2 16 December 1989 CONTENTS CHAPTER 1 INTRODUCTION 1.1 Block Diagram Of SXTE-J Tables . . . . . . . . . 1-2 1.2 Abbreviations And Acronyms . . . . . . . . . . . . 1-2 1.3 Nomenclature . . . . . . . . . . . . . . . . . . . 1-3 1.4 Types Of Parameters . . . . . . . . . . . . . . . 1-5 1.5 Microprocessors And Memory . . . . . . . . . . . . 1-5 1.5.1 SXTE-U . . . . . . . . . . . . . . . . . . . . . 1-5 1.5.2 SXTE-J . . . . . . . . . . . . . . . . . . . . . 1-5 CHAPTER 2 SXTE-J TABLES 2.1 Entry Table (ENTT) . . . . . . . . . . . . . . . . 2-1 2.2 Sequence Table (FWI SEQT And PFI SEQT) . . . . . . 2-2 2.2.1 Sequence Tables - Mode Transitions . . . . . . . 2-3 2.2.2 PFI SEQ Parameters . . . . . . . . . . . . . . . 2-5 2.2.3 FWI SEQ Parameters . . . . . . . . . . . . . . . 2-6 2.2.4 Use Of Sequence Tables . . . . . . . . . . . . . 2-7 2.2.4.1 Patrol Images . . . . . . . . . . . . . . . . . 2-7 2.2.4.2 Full Width Images (FWI) . . . . . . . . . . . . 2-7 2.2.4.3 Partial Frame Images (PFI) . . . . . . . . . . . 2-8 2.2.4.4 Interleaving Of Different Images . . . . . . . . 2-8 2.2.5 Exposure Levels . . . . . . . . . . . . . . . 2-10 2.2.6 Filters . . . . . . . . . . . . . . . . . . . 2-12 2.2.7 CCD Summation Modes . . . . . . . . . . . . . 2-12 2.3 Exposure Level Default Table (EXPDT) . . . . . . 2-14 2.4 ROI Tables (ROIT) . . . . . . . . . . . . . . . 2-15 2.5 Common Table (COMT) . . . . . . . . . . . . . . 2-17 CHAPTER 3 AUTOMATIC ROI SELECTION (ARS) 3.1 Introduction To ARS . . . . . . . . . . . . . . . 3-1 3.2 Definition Of The Macro Pixel . . . . . . . . . . 3-1 3.3 When A Patrol Image Is Taken . . . . . . . . . . . 3-2 3.4 QT ARS-1 Algorithm . . . . . . . . . . . . . . . . 3-2 3.5 QT ARS-2 Algorithm . . . . . . . . . . . . . . . . 3-4 3.6 FL ARS Algorithm . . . . . . . . . . . . . . . . . 3-4 CHAPTER 4 AUTOMATIC EXPOSURE CONTROL (AEC) 4.1 AEC Algorithm . . . . . . . . . . . . . . . . . . 4-1 4.1.1 Count Pixels . . . . . . . . . . . . . . . . . . 4-1 4.1.2 Modifiying Exposure Level . . . . . . . . . . . 4-2 4.2 Filter Alternation . . . . . . . . . . . . . . . . 4-3 Table of Contents Page 3 16 December 1989 4.2.1 General Alogrithm . . . . . . . . . . . . . . . 4-3 4.2.2 Finding Default Starting Exposure Level . . . . 4-3 4.2.3 Example Of Correction For Over Exposure . . . . 4-4 4.2.4 Example Of Correction For Under Exposure . . . . 4-4 4.3 AEC Timing . . . . . . . . . . . . . . . . . . . . 4-5 4.4 General Information On AEC . . . . . . . . . . . . 4-6 CHAPTER 5 SXTE-J IMAGE BUFFERS CHAPTER 6 AUTOMATIC ROI TRACKING (ART) 6.1 Introduction . . . . . . . . . . . . . . . . . . . 6-1 CHAPTER 7 AUTOMATIC ROI RELOCATION (ARR) 7.1 Introduction . . . . . . . . . . . . . . . . . . . 7-1 CHAPTER 8 REFERENCE TABLES 8.1 Cycle Time For SXT Exposures . . . . . . . . . . . 8-2 8.2 Time Interval Between Exposures . . . . . . . . . 8-3 8.3 Number Of Images That Can Be Taken In One Orbit (60 Minutes) . . . . . . . . . . . . . . . . . . . 8-4 8.4 Number Of Images To Fill The BDR . . . . . . . . 8-4 8.5 Different Telemetry Rates . . . . . . . . . . . . 8-5 8.6 Different Fields Of View For ROIs . . . . . . . . 8-6 8.7 SXT Part Of Telemetry Data Block In One Minor Frame . . . . . . . . . . . . . . . . . . . . . . 8-7 8.8 Sample PFI SEQ Table . . . . . . . . . . . . . . . 8-8 8.9 Sample ROI Table . . . . . . . . . . . . . . . . . 8-9 8.10 Sample EXPDT Table . . . . . . . . . . . . . . . . 8-9 8.11 Sample Common Table Values . . . . . . . . . . . . 8-9 8.12 Sample FWI SEQ Table . . . . . . . . . . . . . . 8-10 CHAPTER 9 GUIDELINES FOR SPECIAL OBSERVING SEQUENCES 9.1 Movies . . . . . . . . . . . . . . . . . . . . . . 9-2 9.2 One Patrol Image Per Orbit . . . . . . . . . . . . 9-3 9.3 One Patrol Image Per Mode Change . . . . . . . . . 9-4 9.4 Only One Full Width Image Per Orbit . . . . . . . 9-5 CHAPTER 10 SPECIFYING OBSERVATIONS 10.1 Parameters That Need To Be Specified . . . . . . 10-1 10.1.1 Sample "Worksheet" For Defining Sequences . . 10-2 Table of Contents Page 4 16 December 1989 10.1.2 Full Description Of SXT Sequence Table Parameters . . . . . . . . . . . . . . . . . . 10-3 10.1.3 Full Description Of BCS Parameters . . . . . . 10-3 10.2 Sample Observation Sequence . . . . . . . . . . 10-4 10.2.1 Science Objectives . . . . . . . . . . . . . . 10-4 10.2.2 Observational Objectives . . . . . . . . . . . 10-4 10.2.3 Assumptions/Actions: . . . . . . . . . . . . . 10-5 10.2.4 Overview Of Actual Sequence (filling In Worksheet) . . . . . . . . . . . . . . . . . . 10-5 10.2.4.1 Pre-Flare Sequence . . . . . . . . . . . . . . 10-5 10.2.4.2 Flare Sequence . . . . . . . . . . . . . . . . 10-5 10.2.4.3 Flare Decay Sequence . . . . . . . . . . . . . 10-5 10.2.5 SXT Timeline/Table Of The Sequence . . . . . . 10-5 10.2.5.1 Pre-Flare Sequence . . . . . . . . . . . . . . 10-6 10.2.5.2 Flare Sequence . . . . . . . . . . . . . . . . 10-7 10.2.5.3 Flare Decay Sequence . . . . . . . . . . . . . 10-8 Table of Contents Page 5 16 December 1989 APPENDIX A SOLAR-A DP INDEPENDENT OF SXTE-J A.1 Introduction . . . . . . . . . . . . . . . . . . . A-2 A.1.1 Different Modes And Rates . . . . . . . . . . . A-2 A.1.2 Different Sub-systems . . . . . . . . . . . . . A-2 A.1.3 Scientific Instruments . . . . . . . . . . . . . A-4 A.2 Telemetry . . . . . . . . . . . . . . . . . . . . A-5 A.2.1 Launch Information And The Orbit . . . . . . . . A-5 A.2.2 Ground Link . . . . . . . . . . . . . . . . . . A-5 A.2.3 Options When There Are Transmission Problems . . A-6 A.2.4 Deep Space Network (DSN) . . . . . . . . . . . . A-7 A.2.5 Visibile VS Invisible Orbits . . . . . . . . . . A-7 A.2.6 Successive Ground Links After Only One Orbit (SGLOOO) . . . . . . . . . . . . . . . . . . . . A-7 A.2.7 Frame Formats . . . . . . . . . . . . . . . . . A-8 A.2.8 Timing Of Telemetry Rate Change . . . . . . . . A-9 A.2.8.1 Slow Case (Non-Emergency) . . . . . . . . . . . A-9 A.2.8.2 Fast Cases . . . . . . . . . . . . . . . . . . A-10 A.3 Automatic Control Of Observing Mode . . . . . . A-11 A.3.1 Basic Principles . . . . . . . . . . . . . . . A-11 A.3.1.1 Philosophy . . . . . . . . . . . . . . . . . . A-11 A.3.1.2 Basic Algorithm . . . . . . . . . . . . . . . A-11 A.3.1.3 When The Different Modes/Rates Are Used . . . A-12 A.3.2 Observation Mode Change Logic For Flares . . . A-13 A.3.2.1 Flare Alarm Task . . . . . . . . . . . . . . . A-14 A.3.2.2 Mode Change Task . . . . . . . . . . . . . . . A-14 A.3.3 Flare Trigger . . . . . . . . . . . . . . . . A-14 A.3.3.1 Normal Flare Threshold (NFT) . . . . . . . . . A-15 A.3.3.2 Great Flare Threshold (GFT) . . . . . . . . . A-16 A.3.3.3 Flare End Threshold (FET) . . . . . . . . . . A-16 A.3.3.4 Flare Mode Minimum Duration . . . . . . . . . A-16 A.3.4 Leaving Flare Mode . . . . . . . . . . . . . . A-16 A.3.5 Avoiding The Radiation Belt . . . . . . . . . A-18 A.4 Writing Data To The Bubble Data Recorder (BDR) . A-19 A.4.1 Write Protection Level (X) . . . . . . . . . . A-19 A.4.2 Recording Importance Level (Y) . . . . . . . . A-20 A.4.3 BDR Block Pointer (P) . . . . . . . . . . . . A-20 A.4.4 Basic Algorithm . . . . . . . . . . . . . . . A-20 A.4.5 More Detail On BDR Protection . . . . . . . . A-21 A.4.6 Example Of Writing To The BDR . . . . . . . . A-23 A.4.6.1 Example/Question 1 Of Writing To The BDR . . . A-24 A.4.6.2 Example/Question 2 Of Writing To The BDR . . . A-24 A.4.6.3 Example/Question 3 Of Writing To The BDR . . . A-24 A.4.6.4 Example/Question 4 Of Writing To The BDR . . . A-25 A.5 Reading Data From The Bubble Data Recorder (BDR) A-26 A.6 DP Hardware . . . . . . . . . . . . . . . . . . A-27 A.7 DP Software . . . . . . . . . . . . . . . . . . A-28 A.7.1 Identification Code (IC) . . . . . . . . . . . A-28 A.7.2 BC/DC Commands . . . . . . . . . . . . . . . . A-28 A.7.3 Organized Commands (OG) . . . . . . . . . . . A-28 A.7.4 Real Time Organized Commands (ROG) . . . . . . A-29 Table of Contents Page 6 16 December 1989 A.7.5 Interupt Organized Commands (IOG) . . . . . . A-29 A.7.6 Operation Program (OP) . . . . . . . . . . . . A-30 A.7.6.1 Starting Execution Of An OP . . . . . . . . . A-30 A.7.6.2 Stopping Execution Of An OP . . . . . . . . . A-31 A.7.6.3 Examples Of Using Operation Programs (OP) . . A-31 Table of Contents Page 7 16 December 1989 APPENDIX B HOW TO USE AEC B.1 Introduction . . . . . . . . . . . . . . . . . . . B-2 B.1.1 . . . . . . . . . . . . . . . . . . . . . . . . B-2 B.2 Problem Areas . . . . . . . . . . . . . . . . . . B-2 APPENDIX C FUNDAMENTAL CAMERA OPERATION & CAPABILITIES C.1 Commanding . . . . . . . . . . . . . . . . . . . . C-2 C.2 Baseline Stabilization (BLS) Pixels . . . . . . . C-2 C.3 Light Transfers . . . . . . . . . . . . . . . . . C-2 CHAPTER 1 INTRODUCTION The SXT instrument is controlled by tables. Depending on the current mode (Flare, Quiet, Night, ...) of the spacecraft as well as the current telemetry rate (High, Med, Low), a set of sequence tables are selected. The sequence table contains the parameters which define a set of exposures. The exposure level of these exposures can be adjusted by a program (AEC - Automatic Exposure Control) and the pointing of the exposures can be adjusted by one of many programs (ARS - Automatic ROI Selection, ART - Automatic ROI Tracking, or ARR - Automatic ROI Relocation). The following document attempts to describe the different tables, how the different tables interact, and some of the basics of the algorithms of the programs. INTRODUCTION Page 1-2 Block Diagram Of SXTE-J Tables 16 December 1989 1.1 Block Diagram Of SXTE-J Tables - The block diagram shown below can be periodically referenced while reading the different sections. Key: --> and <-- indicate logical flow (tables pointing to other tables) ==> and <== indicate programs which write into that table ARS =============>! ! ART =============>! ! !<======== ARR =============>! ! ! ! +-------------+ ! !------------->| Observing | ! ! | Region Table| +---------------+ | (ROIT) | | PFI Sequence | +-------------+ --------------->| Table | ! | (PFI SEQ) | +-------------+ ! +---------------+ | Exposure Lev| +-----------+ ! AEC | Default Tabl| DP Mode | Entry | !<=============| (EXPDT) | -------->| Table | +-------------+ | (ENTT) | +-----------+ ! +---------------+ ! | FWI Sequence | --------------->| Table | | (FWI SEQ) | +---------------+ +-----------+ | Common | | Table | | (COMT) | +-----------+ 1.2 Abbreviations And Acronyms - See next section for full explanation of these acronyms PFI Partial Frame Image FWI Full Width Image ROI Region of Interest OR Observing Region ARS Automatic ROI Selection AEC Automatic Exposure Control INTRODUCTION Page 1-3 Abbreviations And Acronyms 16 December 1989 ARR Automatic ROI Relocation ART Automatic ROI Tracking NOP No Operation (null command) FOV Field of View DPE SXTE-J/DP Exposure Level MBE SXTE-U Mailbox Exposure Level 1.3 Nomenclature - PFI (Partial Frame Image): A single partial frame image refers to a region on the CCD which is 64x64 pixels OUT of the camera. An PFI should be specified as a "NxM PFI", where "NxM" is the on chip summation. There can be 1x1, 2x2, and 4x4 on chip summation. The fields of view of these different summations is 2.6' x 2.6, 5.2' x 5.2, 10.4' x 10.4'. "PFI Mode" is the mode where partial frame images are being taken. FWI (Full Width Image) Full width images consists of all columns on the CCD (complete lines) of a predetermined width (number of lines). Due to limitations on the buffer size and shape, it is possible to get only a predetermined total number of lines out of the camera. For 1x1 summation it is 64, 128, 256, or 512; for 2x2 summation it is 128, 256, or 512; and for 4x4 summation it is 256 lines. FWI used to be called FWI (Full Width Image). "FWI Mode" is the mode where full width images are being taken. ROI (Region of Interest): An ROI is a cluster of PFIs. The PFIs must be arranged in a rectangular shape. For example, a 3x3 ROI consists of 9 PFIs arranged in a square, a 1x4 ROI consists of 4 PFIs placed side by side in the north-south direction. The field of view for an ROI depends on the number of PFIs AND the summation mode of the PFIs. An ROI should be specified as a "NxM ROI", where "N" is the number of PFIs in the east-west direction, and "M" is the number of PFIs in the north-south. Because of the way the buffers are arranged, it is necessary to have "M" separate exposures for a single ROI, where "M" is the number of north-south PFIs. The maximum value of N and M is 16 for 1x1 summation, 8 for 2x2, and 4 for 4x4. A PFI sequence is defined in terms of ROIs (ROIs are made up of PFIs). INTRODUCTION Page 1-4 Nomenclature 16 December 1989 ROIs only apply to PFI mode. LOI (Latitude of Interest): A full width image can be defined to consist of 1, 2, 3 or 4 LOIs. An LOI consists of all columns on the CCD (complete lines) of a predetermined width (number of lines). Different LOIs are defined by setting a starting line and a width. There can be "gaps" between LOIs which are lines that are not read out of the camera. LOIs differs from ROIs in that only one exposure is required, even if there are several LOIs. LOIs only apply to FWI mode. Image: A single "image" is all of the PFIs mosaiced together to make the ROI when in PFI mode, and is the whole FWI when in FWI mode. The PFI and FWI sequence tables require the parameters for each image (Img 1-1, Img 3-4, ...). OR (Observing Region): An observing region is a generic term for a field of view. An OR refers to a single ROI when in PFI mode, and refers to a single LOI when in FWI mode. It is suggested to use the terms ROI and FWI instead of OR when possible. PFI Strip: A PFI strip is a block of PFIs in the east-west direction and only one PFI in the north-south. There is one exposure per PFI strip. Exposure: An exposure is defined as each time the CCD is read out. Generally this is every time that the shutter is commanded open. Example of defining PFI observing regions: "a 2x2 ROI with 2x2 summation" ==> Field of view = 10.4' x 10.4' "a 4x1 ROI with 4x4 summation" ==> Field of view = 42.0' x 10.4' "a 16x8 ROI with 1x1 summation" ==> Field of view = 42.0' x 21.0' "a 1x3 ROI using 2x2 PFIs" ==> Field of view = 5.2' x 15.6' (in the last example "2x2 PFIs" indicates it is 2x2 summation") ARS (Automatic ROI Selection) Automatically searches the patrol image to find up to four of the brightest regions. AEC (Automatic Exposure Control) Updates both the SXTE-J/DP exposure time and filters used. ARR (Automatic ROI Relocation) Automatically changes the size of the ROI (ROI mode) to cover entire INTRODUCTION Page 1-5 Nomenclature 16 December 1989 flaring region when an observed flare excceeds its boundary of FOV. ART (Automatic ROI Tracking) Tracks the movements of specified observing regions due to spacecraft attitude drift. Instead of changing the pointing of the telescope, the same function is served by choosing a different part of the CCD image. ART software uses the fine sun sensor data to maintain pointing. 1.4 Types Of Parameters - Fixed Parameters:: Changes are basically not required after launch. Changes will be made with RAM patch. Static Parameters:: Parameters are updated by BC commands from Ground Dynamic Parameters:: Parameters are dynamically updated by onboard software. 1.5 Microprocessors And Memory - 1.5.1 SXTE-U - The SXTE-U microprocessor is the NSC800, which has 8 bits and a clock speed of 2.5 MHz. There is a 4Kbyte ROM that is loaded into RAM at initial power up of the SXTE-U system and also on a cold reset. 1.5.2 SXTE-J - The SXTE-J microprocessor is the 80C86, which has 16 bits and a clock speed of 4 MHz. The SXTE-J uses 128 Kbytes of memory (~10 Kbytes of which are used for tables) Does that include image buffers? ??Saku?? CHAPTER 2 SXTE-J TABLES 2.1 Entry Table (ENTT) - There is one entry table, and the table has 8 different parameters. Parameter DP Mode Item --------- ------- ---- 0 Quiet/High FWI Sequence Table # 1 Quiet/High PFI Sequence Table # 2 Quiet/Med FWI Sequence Table # 3 Quiet/Med PFI Sequence Table # 4 5 Flare/High PFI Sequence Table # 6 7 Flare/Med PFI Sequence Table # NOTE: There are no full width images ever taken during flare mode. SXTE-J TABLES Page 2-2 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2 Sequence Table (FWI SEQT And PFI SEQT) - There are separate tables for full width images (FWI) and partial frame images (PFI). There are 13 separate images for each sequence tables, and there are 24 image set-up parameters available for each exposure. There are 4 FWI tables and 4 PFI tables available. NOTE: "Image" for PFI mode refers to observing regions, which can be several exposures (motions of the shutter). "Image" for FWI is the full width single exposure, even if there are several FWI-ROIs. LOOP 1 (n=infinity) Img 1-1 --------------------+ LOOP 2 (n= ) | Img 2-1 ------------+ | Img 2-2 | | LOOP 3 (n= ) | | Img 3-1 ----+ | | Img 3-2 | | | Img 3-3 | | | Img 3-4 ----+ ---+ | LOOP 4 (n= ) | Img 4-1 ------------+ | Img 4-2 | | LOOP 5 (n= ) | | Img 5-1 ----+ | | Img 5-2 | | | Img 5-3 | | | Img 5-4 ----+ ---+ ---+ NOTE: Currently the FWI SEQ table differs slightly from the PFI SEQ table in that there are no "Img 2-2" and "Img 4-2" available. The two tables will match in this respect for the next software test. SXTE-J TABLES Page 2-3 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2.1 Sequence Tables - Mode Transitions - When making mode transitions (from quiet to flare and back again) it is possible to either reset the loops described above to Img 1-1, or to continue from where it left off. The following describes what happens. Seq Transition Flare and Quiet Loops reset to Img 1-1 use same PFI table? State on 8/88 Flight Model --- ---------- ------------------- ------------- ------------ PFI Quiet -> Flare No N/A N/A Yes Yes No PFI Flare -> Quiet No N/A N/A Yes Yes No PFI Quiet -> Flare -> Quiet No Yes Yes Quiet -> Flare -> Quiet Yes Yes No Flare -> Quiet -> Flare No ?? Yes Flare -> Quiet -> Flare Yes ?? No FWI Quiet -> Flare -> Quiet N/A Yes No ?? Review ?? The only time that the image readout is aborted (reset to forget image data that is in buffer) is when "SXT Control" goes from Auto to Manual to Auto. Be aware that the FWI can be discontinuous during the readout, even if the BDR does not have to be overwritten. This occurs because of mode changes to Flare or Night modes (when there is no telemetry allocation for FWI) The decision to not reset the loops to 1-1 for the different mode transitions is to not interupt a "movie" sequence during a mode change. There will be a partial interuption because a patrol image must be taken at the Quiet to Flare mode transtion (and also Flare to Quiet transition??) ?? Saku ?? The capability to choose from the ground whether or not to reset to the start of a sequence is not available ??. ?? Saku ?? During the Night to Day transition, if the the current mode is the same mode before Night mode occured, the tables are NOT re-loaded (re-initialized). For example, imagine that the DP was in Quiet Mode before night with AEC on for certain exposures. The exposure level has been changed from its default starting value. When day starts, if the DP goes into Quiet Mode, the exposure levels are NOT reset to their original default starting values (they use what the AEC last adjusted them to be the orbit before). This is also true for filter alternation levels. If the same table is used in the two different modes then the exposure levels SXTE-J TABLES Page 2-4 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 and filter alternation level are also not reset. This is important because AEC has already stabilized and should not have to do the same work over again. ?? Saku Confirm ?? SXTE-J TABLES Page 2-5 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2.2 PFI SEQ Parameters - Each table has one set of the following parameters: Parameter Type 1. Number of repeats for each loop - for LOOP 2 Static - for LOOP 3 Static - for LOOP 4 Static - for LOOP 5 Static 2. Reserved Static * 4 EACH of the 13 PFI images ("Img n-m" line listed above) needs: 1. Aspect Door Information Open/Closed Static 2. Shutter Information Exposure level (DPE) Dynamic/AEC Shutter Mode (Frame transfer/Mechanical) Static Dark Image Flag Static 3. Filter Information (*) Filter-A/B Position (Alternation level 0) Static Filter-A/B Position (Alternation level 1) Static Filter-A/B Position (Alternation level 2) Static Filter Alternation Enable/Disable Static Current Filter Alternation level Dynamic/AEC 4. Camera Information Number of full frame flushes Static and # of pre-ROI lines to readout Compression/Resolution/# of ROI Static (&) ROI Table number Static { Start Row of each ROI } { Start Column of each ROI } { Mode of ROI (#rows x #columns) } 5. AEC Information AEC Enable/Disable Static AEC ULT (Upper intensity thresh hold lim) Static AEC LLT (Lower intensity thresh hold lim) Static AEC UAT (Upper limit pixel count limit) Static AEC LAT (Lower limit pixel count limit) Static 6. Reserved (ARR, ART use) Static * 7 Notes: (*) Effective exposure levels of 0 or 1 will require the 10% mask (Filter B, position 2) (&) The resolution parameter might be a Dynamic parameter where the ARR will increase the size of the FOV automatically SXTE-J TABLES Page 2-6 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2.3 FWI SEQ Parameters - Each FWI table has one set of the following parameters: Parameter Type 1. Number of repeats for each loop - for LOOP 2 Static - for LOOP 3 Static - for LOOP 4 Static - for LOOP 5 Static 2. Reserved Static * 4 EACH of the 13 FWI images ("Img n-m" line listed above) needs: 1. Aspect Door Information Open/Closed Static 2. Shutter Information Exposure level (DPE) Static Shutter Mode (Frame transfer/Mechanical) Static Dark Image Flag Static 3. Filter Information Filter-A/B Position Static 4. Camera Information Number of full frame flushes Static and # of pre-ROI lines to readout Compression/Resolution/# of ROIs Static ROI Start Row #1 Static ROI Width #1 Static ROI Start Row #2 Static ROI Width #2 Static ROI Start Row #3 Static ROI Width #3 Static ROI Start Row #4 Static ROI Width #4 Static BLS on/off (Calibration Mode) Static FWI Mode Static 5. Reserved Static * 7 NOTE: There is no AEC, ARS, ART, or ARR for full width images. SXTE-J TABLES Page 2-7 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2.4 Use Of Sequence Tables - There are essentially three different images that can be taken. They are listed here by priority: 1. Patrol images 2. Full Width Images (FWI) 3. Partial Frame Images (PFI) It is not possible to write PFI data in the FWI telemetry block even if there are no exposures in the FWI sequence table. 2.2.4.1 Patrol Images - The frequency of patrol image exposures is a variable parameter that can be set to be an exposure between every 32 seconds and 137 hours. The frequency of the patrol image is defined in absolute time and is therefore independent of the telemetry rate. There is one frequency defined for QT ARS-1 and ARS-2 and one frequency for FL ARS. A patrol image will typically be taken every minute or two when in either Flare or Quiet Mode. The patrol image is a 4x4 image of HALF of the CCD. The Patrol image is used for automatic ROI selection (ARS) and is typically not sent to the ground, however it is possible to manually command the spacecraft to send the patrol image to the ground. 2.2.4.2 Full Width Images (FWI) - Full Frame images are not necessarily images of the full CCD, they simply imply that all columns of the lines selected will be sent to the ground. There are four different FWI Modes: KBytes Lines Out of Camera Mode of Data 1x1 2x2 4x4 ---- ------- --------------------------------- 0 512 512 N/A N/A 1 256 256 512 N/A 2 128 128 256 N/A 3 64 64 128 256 SXTE-J TABLES Page 2-8 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2.4.3 Partial Frame Images (PFI) - Partial frame images are single elements of observing regions. An observing region is made up of ROIs. A single ROI is set of 64x64 pixels. For a single ROI, the following is true: Resolution Lines on CCD Fraction of CCD Field of View (arcMin) ---------- ------------ --------------- ---------------------- 1x1 64x64 1/16 x 1/16 2.6 x 2.6 2x2 128x128 1/8 x 1/8 5.2 x 5.2 4x4 256x256 1/4 x 1/4 10.4 x 10.4 NOTE: There are always 64 lines sent out of the camera when in partial frame image mode. There is a special mode for PFI images that will allow two or four images to be taken in one major frame when in the high telemetry rate (2 or 4 exposures in the 2 seconds). The purpose is to allow for higher temporal resolution. For the 1 and .5 second cadence ROI, the following is true for each image: Exposure Cadence Resolution Lines on CCD Field of View (arcMin) (*) ---------------- ---------- ------------ ---------------------- 0.5 sec 1x1 64x16 2.6 x 0.65 0.5 sec 2x2 128x32 5.2 x 1.3 0.5 sec 4x4 256x64 10.4 x 2.6 1 sec 1x1 64x32 2.6 x 1.3 1 sec 2x2 128x64 5.2 x 2.6 1 sec 4x4 256x128 10.4 x 5.2 NOTE: The field of view is defined as FOV east-west x north-south. Notice that the shape in the east-west direction does not change. 2.2.4.4 Interleaving Of Different Images - The patrol image takes the highest priority, the full width second priority, and the partial frames last priority. Patrol images are separated by a fixed length of time. When the appointed time arrives, the PFI and FWI sequences will be interupted (told to pause) and the patrol image is taken. When in Quiet Mode, full widths are taken. If the FWI buffer is empty and a patrol image is not needed, the next exposure taken will be a full width. It will interupt the PFI sequence. The buffer is then read out a the rate determined by the SXT Format (PFI:FWI 8:2 or 2:8). Since there is more data, and sometimes the allocation for FWIs is small, this will take a long time. During this time, PFI images are taken. SXTE-J TABLES Page 2-9 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 Time !--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--! Patrol Images # # # # FWI Images ^ ^ ^ ^ PFI Images * * * * * * * * * * * * * NOTE: FWI images are only interleaved in Quiet mode (no FWI in Flare mode) Notice that the patrol image appears at regular intervals while the FWIs are sporatic. The cadence of the FWIs depends on the size of the image taken. If the same sized picture is taken each time, the cadence will be regular. The PFI are taken any time that patrol and FWI images are not taken (and the PFI buffer is empty). NOTE: When in Quiet mode, if either the PFI or FWI table is full of NOPs, then the telemetry block that it is supposed to write its data to SXT (1) or SXT (2) is filled with "55"s. SXTE-J TABLES Page 2-10 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2.5 Exposure Levels - There are two different exposure level specifications. There is the SXTE-J/DP expsoure time (DPE) and the SXTE-U mailbox exposure time (MBE). These two different levels are needed because the effective exposure level (DPE) can be adjusted by using the 10% mask. DPE MBE Effective Exposure Shutter Exposure --- --- ------------------ ---------------- 0 0 0.1 mSec * 1 mSec 1 1 0.3 * 3 2 0 1.0 1 3 1 3 3 4 4 6 * 60 %% 5 5 12 * 120 %% 6 2 20 20 7 3 30 30 8 4 60 60 9 5 120 120 10 6 250 250 11 7 500 500 12 8 1 Sec 1 Sec 13 9 2 2 14 10 4 4 15 11 8 8 16 12 16 16 17 13 32 32 18 14 64 64 19 15 128 128 20 16 256 256 21 17 Ground Loaded Ground Loaded %% 22 18 0.25 sec 0.25 sec 23 19 0.50 sec 0.50 sec 24 20 0.75 sec 0.75 sec 25 21 1.00 sec 1.00 sec 26 22 1.25 sec 1.25 sec 27 23 1.50 sec 1.50 sec 28 24 1.75 sec 1.75 sec 29 25 2.00 sec 2.00 sec 30 26 2.25 sec 2.25 sec 31 27 2.50 sec 2.50 sec 32 28 2.75 sec 2.75 sec 33 29 3.00 sec 3.00 sec 34 30 3.25 sec 3.25 sec 35 31 3.50 sec 3.50 sec 36 32 3.75 sec 3.75 sec 37 33 4.00 sec 4.00 sec Notes: * denotes exposure levels that use the 10% mask MBE exposure levels 18-33 are used for calibration SXTE-J TABLES Page 2-11 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 SXTE-J TABLES Page 2-12 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 2.2.6 Filters - There are two filter wheels, each wheel has six filter positions. Front Filter Wheel (closest to sun) -- Filter Wheel A Position Acronym Filter Command 1 OPN Open position 2 OP2 Narrow Band Optical (4293-4323A) 3 TN3 Al 1200 A (Same as front wheel) (Thin 3) 4 DIF Diffuser 5 OP1 Broad Band Optical (4600-4800A) 6 10M 10% X-Ray Mask Back Filter Wheel (closest to CCD) -- Filter Wheel B Position Acronym Filter Command 1 OPN Open position 2 TN1 Al 1200 A (Thin 1) 3 MED 3000A Al, 2000A Mg, 6000A Mn (Medium) (Dagwood?) 4 TK1 Be 100 microns (Thick 1) 5 TK2 Al 12 microns (Thick 2) 6 TN2 Mg 1200 (TBD) (Thin 2) The positions are numbered clockwise as viewed from the CCD for the back filter wheel, and are numbered clockwise as viewed from the sun for the front filter wheel. 2.2.7 CCD Summation Modes - There are three on chip summation modes: Summation Resolution 1x1 2.4" 2x2 4.9" 4x4 9.8" There is only one gain setting for all of the summation modes. This means that an exposure level that is 4000 counts for 1x1 summation (near saturation) will be completely saturated for 2x2 or 4x4 summation. The exposure duration will haveto be reduced by a factor of 4 for 2x2 summation and 16 for 4x4 summation. The serial transfer register has a capacity of approximately 1.6 times the well capacity on the chip. Saturation can occur: a) on the chip b) in the serial transfer register (north/south summing) c) in the summing well (east/west summing) SXTE-J TABLES Page 2-13 Sequence Table (FWI SEQT And PFI SEQT) 16 December 1989 d) in the ADC (analog to digital converter) SXTE-J TABLES Page 2-14 Exposure Level Default Table (EXPDT) 16 December 1989 2.3 Exposure Level Default Table (EXPDT) - If the AEC needs to adjust the exposure by changing the filter filter alternation) this table specifies the default exposure level with which to start exposures. AEC will then adjust for the correct exposure level by looking at the image data. There are 8 different parameters in the table. There is only one table. Parameter Alternate Filter Combination (A/B) Default Exposure Level --------- ---------------------------------- ---------------------- 0 n0/m0 x 1 n1/m1 x 2 n2/m2 x 3 n3/m3 x 4 n4/m4 x 5 n5/m5 x 6 - 7 - Each filter combination (ie: n0/m0) is a different combination of filters. For example, the 6 filter combinations above could be something like 1/2, 5/3, 4/4, 2/5, 3/2, 1/6. The AEC program will check each filter combination in the EXPDT table to see if the new filters to be used (because of filter alternation) are listed in the table. If there is a match, then the default exposure level use accessed. SXTE-J TABLES Page 2-15 ROI Tables (ROIT) 16 December 1989 2.4 ROI Tables (ROIT) - There are 9 different ROI tables. Each table is a different observing region on the sun. There are 4 parameters for each table. Parameter Parameter Type --------- -------------- 0 Shape of ROI Static 1 Row center address Dynamic (QT ARS-1) for Tables 0-3 and 8 Dynamic (QT ARS-2) for Tables 0-3 Dynamic (FL ARS) for Tables 8 Dynamic (ART) for Tables 4-7 2 Column Center Address (see ROI Center Adress) 3 NOTE: The reserved parameter will most likely be used for ART enable/disable. When ARS is enabled:: A. QT ARS can only update observing regions 0 through 3 and 8. B. FL ARS updates observing region 8 only. The Shape of ROI defines the number of PFIs to "mosaic" together to achieve an ROI. The Mode of ROI uses a nibble (4 bits) to define the number of PFIs in each the east/west and the north/south directions. A Mode of ROI is defined as NxM, where N is the number of PFIs in the east/west direction, and M is the number in the north/south. Some examples of Modes of ROI are shown below. Shape Lines Out Size of FOV (arcMin) Number of 1x1 2x2 4x4 Exposures ----- --------- ----------------------------------- --------- 1x1 ROI 64x 64 2.6 x 2.6 5.2 x 5.2 10.4 x 10.4 1 +-+ +-+ 2x1 ROI 128x 64 5.2 x 2.6 10.4 x 5.2 20.8 x 10.4 1 +-+-+ +-+-+ 4x1 ROI 256x 64 10.4 x 2.6 20.8 x 5.2 41.6 x 10.4 1 +-+-+-+-+ +-+-+-+-+ 1x4 ROI 64x256 2.6 x10.4 5.2 x 20.8 10.4 x 41.6 4 +-+ +-+ +-+ +-+ +-+ SXTE-J TABLES Page 2-16 ROI Tables (ROIT) 16 December 1989 2x2 ROI 128x128 5.2 x 5.2 10.4 x 10.4 20.8 x 20.8 2 +-+-+ +-+-+ +-+-+ 4x4 ROI 256x256 10.4 x10.4 20.8 x 20.8 41.6 x 41.6 4 +-+-+-+-+ +-+-+-+-+ +-+-+-+-+ +-+-+-+-+ +-+-+-+-+ When the partial frame image is read into SXTE-J, ALL columns of the lines are stored in memory. The partial frame buffer size will only hold 64 lines. This means that we can access any number of columns for a single exposure, but are limited to 64 lines per partial frame exposure. Because of this, each PFI strip requires a separate exposure. The number "M" above is the number of exposures required. There is only one exposure level used for all of the exposures. SXTE-J TABLES Page 2-17 Common Table (COMT) 16 December 1989 2.5 Common Table (COMT) - Parameter Item --------- ---- 0 SXT Format (PFI:FWI 2:8 8:2) 1 AEC Exposure step size 2 AECL 3 AECH0 4 AECH1 5 AEC 10% Mask Enable/Disable 6 PFI Buffer Select 7 Patrol Buffer Select 8 Flare Patrol Image - 9 - Flush Count 10 - Shutter Mode 11 - Filter A/B 12 - 13 - 14 - Aspect Door 15 - Exposure Level 16 - Dark Current Image 17 - Resolution/Compression 18 - ROI Start Row 19 - ROI Width 20 Quiet Patrol Image - Same parameters as Flare . . 31 32 QT ARS Enable/Disable 33 QT ARS 1 (or) 2 34 FL ARS Enable/Disable 35 Morning Patrol Enable/Disable 36 QT ARS Interval 37 FL ARS Interval 38 ARS Minimum Separation Parameter 39 ART Enable/Disable 40 ART TFSS (or) IRU 41 ARS AEC Exposure Step Size 42 ARS AEC AECL 43 ARS AEC AECH0 44 ARS AEC AECH1 45 ARS AEC AEC 10% Mask Enable/Disable 46 SXT Morning Interval ?? Sauk ?? 47 SXT Evening Interval ?? Saku ?? 48 ARS AEC Filter (Alternation enabled?) ?? Saku ?? 49 ARS AEC Filter (Alternation level) ?? Saku ?? 50 ARS AEC (enable/disable?) ?? Saku ?? 51 ARS AEC ULT 52 ARS AEC LLT SXTE-J TABLES Page 2-18 Common Table (COMT) 16 December 1989 53 ARS AEC UAT 54 ARS AEC LAT 55 56 Master/Slave Select (FWI Mode = 0) 57 Slave Buffer ( " ) 58 Master/Slave Select (FWI Mode = 1) 59 Slave Buffer ( " ) 60 Master/Slave Select (FWI Mode = 2) 61 Slave Buffer ( " ) 62 Master/Slave Select (FWI Mode = 3) 63 Slave Buffer ( " ) NOTE: Even though the patrol image has the resolution and ROI width appearing here as parameters, they are fixed as 4x4 summation and 128 lines out of the camera (due to buffer size constraints). CHAPTER 3 AUTOMATIC ROI SELECTION (ARS) 3.1 Introduction To ARS - There are two different Automatic ROI Selection algorithms available to the scientist when in the Quiet Mode, and one ARS algorithm while in the Flare Mode. QT ARS-1 is used to search the whole sun for the four brightest active regions and is commonly refered to as the "Search Mode" ARS. QT ARS-2 is used to track an active region as the region moves due to solar rotation and due to spacecraft point oscillations. This mode is commonly refered to as the "Tracking Mode" ARS. Different ARS Modes Available QT ARS-1 QT ARS-2 FL ARS The QT ARS and FL ARS have separate parameters available to set up the exposure characteristics (different filters, regions, exposures). Also, FL ARS has its own automatic exposure control. ?? Saku ?? ONLY FL ARS?? Is FL-ARS same as QT-ARS-1?? The is only one ARS on/off switch. If ARS is on, it is on for both for Quiet and Flare modes. 3.2 Definition Of The Macro Pixel - Both algorithms make use of macro pixels. A macro pixel is defined as a block of 64x64 raw CCD pixels (1x1 summation) which equals 16x16 quarter summation (4x4 summation) pixels. The FOV of the macro pixel is 2.8 x 2.8 arcMin. AUTOMATIC ROI SELECTION (ARS) Page 3-2 When A Patrol Image Is Taken 16 December 1989 3.3 When A Patrol Image Is Taken - Transition ARS New Patrol Active Image Taken ---------- ---- ----------- Quiet -> Flare FL-ARS Yes Flare -> Quiet QT-ARS-1 Yes (even if period is 137 hours) QT-ARS-2 Yes Night -> Flare FL-ARS Yes Night -> Quiet QT-ARS Only if Morning Enable It is impossible to inhibit the patrol image at the mode transitions. It is possible to set the period between patrol images to be up to 137 hours to not interupt movie sequences. There is an option to take a new patrol image at the start of the spacecraft day for each orbit. 3.4 QT ARS-1 Algorithm - A patrol image is taken with parameters that have be defined and set up in tables (see common table description) The patrol image is a 4x4 image that covers half of the CCD. This means that the image out of the camera is 256 columns by 128 lines. All references to pixels in this section will be the pixles out of the camera, not the individual pixels on the CCD. The process used is as follows: 1. Break the patrol image up into macro pixels. Find the total counts for each of these blocks. The resulting "image" will be 16x8. 2. The brightest (8) macro pixel totals are selected. 3. A 32x32 section of the original patrol image centered around the 16x16 macro pixel bright region is selected. The brightest intensity in this sub-section is determined. NOTE: Currently the algorithm looks at each individual pixel intensity. In the flight model a 2x2 or 3x3 summation MIGHT BE performed to reduce column blem and dark spike affects. <> 4. The 32x32 sub-section is searched again looking for the pixel where the brightest intensity occured. AUTOMATIC ROI SELECTION (ARS) Page 3-3 QT ARS-1 Algorithm 16 December 1989 NOTE: Currently the FIRST occurance of the brightest point is used as the center address (this could be bad if the patrol image is saturated). 5. If the algorithm is looking for the 2nd, 3rd, or 4th brightest active regions, then it will compare the current location to the previous active regions found. (If a bright spot is split across two 64x64 regions, the 32x32 "closer look" can result in the software pointing to the same bright point. There is a minimum distance of separation parameter that must be satisfied (the parameter is located in the common table)). The distance is calculated by taking the sum of the horizontal and vertical separations (not the hypotenuse). If the regions are within the minimum distance, the newly found bright point is ignored. 5. Steps 3 and 4 are repeated until the (4) brightest regions are found or the alogrithm has looked at all 8 of the brightest macro pixels. 6. After all 4 fine pointing calculation, re-sum the macro pixel CENTERED on the fine pointing address. Re-order the brighnesses with these results. 7. Place the position of the brightest region in ROIT-0, the next brightest into ROIT-1, and so on to fill ROIT 0-3. If ARS cannot find (4) different active regions that are separated by more than the minimum separation, then the ROIT locations not updated will have the ROIT-0 location copied into them. If ARS is turned off, it is possible to write addresses into all eight ROI table locations. The images for ROIs that are composed of multiple PFIs will be properly centered on the bright point. Currently the patrol image exposure level is a static parameter. The flight model software will have a separate exposure control algorithm in the ARS program to adjust the exposure level. ?? Saku ?? AEC for QT-ARS Too?? The flight model software will NOT have the capability to subtract dark frame images to eliminate the possibility of column blems or dark spike being selected as active regions by the ARS program. NOTE: If an active region is split across macro pixels, it is possible that the brightest active region (a flare) might not be selected by ARS. It is hoped that there are not many active regions at the same time and that the background is constant across the sun. AUTOMATIC ROI SELECTION (ARS) Page 3-4 QT ARS-1 Algorithm 16 December 1989 Two different periods can be specified for taking patrol images, one for flare mode and one for quiet mode. The longest period available between patrol images is 137 hours. NOTE: ART is not available for ROIT 0-3 (the tables entries that ARS writes to) If there is ever a desire to copy ROIT 0-3 into ROIT 4-7 so that we can use ARS to find the bright points and then ART to track it, the copy must be done manually. 3.5 QT ARS-2 Algorithm - ARS-2 will track specific active regions. This would be desirable when extensive continuous data on a single region is desired, regardless of the size of the other quiet sun active regions. ARS-2 assumes that ARS-1 was run before enabling ARS-2. ?? TODO 3.6 FL ARS Algorithm - ?? TODO 2. This step is only performed for Flare Mode. A first preliminary coarse setting is made by checking the intensity of the four macro pixels closest to the last Quiet mode addresses. The ROI table 0 location is updated with the coarse address of the center of the brightest of these four macro pixels. NOTE: For transitions into Flare mode (from Quiet or Night), ROI table 0 is immediately updated with this second preliminary coarse address. FL ARS has its own automatic exposure control (AEC) which uses an algorithm similar to the AEC used by PFIs (except no filter alternation?) ?? Saku ?? Filter alternation for ARS AEC? CHAPTER 4 AUTOMATIC EXPOSURE CONTROL (AEC) The Automatic Exposure Control (AEC) program will change the exposure level and filter thickness to maintain proper exposures. AEC is only used for PFIs. Filter alternation allows a thicker (or thinner) filter to be used in the case of over or under exposure in order to maintain the optimal exposure durations. 4.1 AEC Algorithm - The AEC can be broken into two areas: 1. Find out if the exposure is under or over exposed 2. Adjust the exposure or filters accordingly 4.1.1 Count Pixels - 1. Check for over exposure Count the number of pixels that are over an upper thresh hold intensity (parameter AEC ULT typically 60 counts) If the number of pixels over that thresh hold is greater than the thresh hold area (parameter AEC UAT typically 10 pixels), then the exposure level needs to be modified (see next section) otherwise, the image is checked for under exposure 2. Checking for under exposure Count the number of pixels that are above a lower thresh hold intensity (parameter AEC LLT typically 20 counts) Note: This calculation is done by counting the number of pixels that AUTOMATIC EXPOSURE CONTROL (AEC) Page 4-2 AEC Algorithm 16 December 1989 are below the lower thresh hold intensity, and subtracting it from 4096. If the number is less than a given value (parameter AEC LAT typically 100) then the exposure level needs to be modified (see next section) For observing regions, ALL pixels in the observing region are counted and then the value "normalized" to be an equivalent overexposure value for one PFI (??terminology). For example, if the observing region is a 2x2 ROI, then the total number of pixels is divided by 4. This is done so that the AEC control values in the sequence tables are independent of the observing region size. The counting is done by hardware when the image is read out of the SXTE-J buffer into the BDR. 4.1.2 Modifiying Exposure Level - There are several steps involved with changing the exposure level. Here is an overview: 1. Increment/decrement level Increment or decrement the current exposure level by the current exposure step size (defined in the common table and typically a value of 1) 2. Check 10% mask use If the new value uses the 10% mask, check to see 10% mask use is allowed. If not, increment/decrement until reaching a level that does not use it (or reaching AECL, AECH, or AECH1) 3. Exceeding AECL, AECH, or AECH1? Filter alternation effective exposure level is lowered by "n" levels (parameter typically 1 or 2). The exposure level will not be set below a pre-set exposure level (parameter AECL in COMMON TABLE). is raised by "n" exposure levels (parameter typically 1 or 2). The exposure level will not be raised past a pre-set exposure level (parameter AECH in COMMON TABLE). ?? Show plots - time sequence (filter alternation, stabilizing) AUTOMATIC EXPOSURE CONTROL (AEC) Page 4-3 Filter Alternation 16 December 1989 4.2 Filter Alternation - As part of the Automatic Exposure Control it is possible to change the filter thicknesses to adjust for proper exposure. Filter alternation can be turned on or off for each set of exposure parameters. 4.2.1 General Alogrithm - If an exposure is still under or over exposed after it has reach the exposure level limits, the AEC will try to change the filters to a thinner or thicker filter. The sequence tables have alternate filter parameters for each exposure. There are three possible filter alternation levels. If it is possible to decrement or increment the filter alternation level (you cannot decrement from alternation level 0), and filter alternation is turned on, filter alternation will occur. An over exposed image means that the filter alternation level will be incremented (a thicker filter is desired). When the filter alternation level is changed to use a new filter, a new default exposure level is needed. The procedure to determine the optimal starting default exposure level involves several steps which are described in the following section. Once the starting exposure level has been determined, the software will continue to take images and receive data. The AEC will then continue to try to find the proper exposure. 4.2.2 Finding Default Starting Exposure Level - The procedure to determine the optimal exposure level to initially try has several steps. 1. Check to see if the new filter combination is currently being used in a separate entry in the sequence table. Only current active PFI sequence table is checked. If the filter is being used in another entry, that exposure level is used as the starting default exposure level That exposure level is used even if AEC is off for that other separate entry 2. If step 1 did not find a match, then the Default Exposure Level Table (EXPDT) is searched to find the new filter in that table. CLEAN?? AUTOMATIC EXPOSURE CONTROL (AEC) Page 4-4 Filter Alternation 16 December 1989 4.2.3 Example Of Correction For Over Exposure - Assume the following: AEC lower limit (AECL) is set to 0 AEC upper limit (AECH) is set to 6. AEC exposure level step size is set to 1 Filter alternation level 0 has a thin filter Filter alternation level 1 has a thick filter Starting default exposure level for filter alternation level 1 is 3 Starting default exposure level for filter alternation level 2 is 4 !Exp-0 !Exp-1 !Exp-2 !Exp-3 !Exp-4 !Exp-5 !Exp-6 !Exp-7 !Exp-8 --------!------!------!------!------!------!------!------!------!------ DPE 3 2 1 0 3 2 1 0 4 Alternation 0 0 0 0 1 1 1 1 2 Level --------!------!------!------!------!------!------!------!------!------ As the AEC determines that Exp-0 is over exposed, the exposure level is decremented. When the minimum exposure level that AEC can selected (AECL) is reached (at EXP-3), filter alternation is attempted. If filter alternation is on and the current alternation level is not level 2, then filter alternation occurs. The default starting exposure level is determined, and then the next exposure is taken. The AEC cannot do anything more when alternation level 2 is reached and the exposure level is at the minimum exposure level allowable for AEC (AECL). 4.2.4 Example Of Correction For Under Exposure - Assume the following: AEC lower limit is set to 0 AEC upper limit is set to 6. AEC exposure level step size is set to 1 Filter alternation level 0 has a thin filter Filter alternation level 1 has a thick filter Starting default exposure level for filter alternation level 1 is 4 Starting default exposure level for filter alternation level 0 is 3 !Exp-0 !Exp-1 !Exp-2 !Exp-3 !Exp-4 !Exp-5 !Exp-6 !Exp-7 !Exp-8 --------!------!------!------!------!------!------!------!------!------ DPE 3 4 5 6 4 5 6 3 4 Alternation 2 2 2 2 1 1 1 0 0 Level --------!------!------!------!------!------!------!------!------!------ As the AEC determines that Exp-0 is under exposed, the exposure level is incremented. When the maximum exposure level that AEC can selected (AECH) is reached (at EXP-3), filter alternation is attempted. If filter alternation is AUTOMATIC EXPOSURE CONTROL (AEC) Page 4-5 Filter Alternation 16 December 1989 on and the current alternation level is not level 0, then filter alternation occurs. The default starting exposure level is determined, and then the next exposure is taken. The AEC cannot do anything more when alternation level 0 is reached and the exposure level is at the maximum exposure level allowable for AEC (AECH). ??UPDATE?? It may be desirable to return to the original filter alternation level as quickly as possible. Because of this, there might be a different set of AECL and AECH levels used for the different alternation levels. 4.3 AEC Timing - The following timing diagram tracks one image's exposure level being updated. Other exposures are occuring during the AEC calculations/update for the exposure in question. !Exp-0 !Exp-1 !Exp-2 !Exp-3 !Exp-4 !Exp-5 --------!--------!--------!--------!--------!--------!----- Exposure Level for Exp-1 Set ! Exp-1 Taken ! Exp Readout U-side to J-side !---! Exp Readout J-side to telemetry !--------! AEC Calculations !--------! Exposure Level Updated ! Exp-5 Taken ! For the exposure level to be stable, the AEC requires two exposures of ANY kind, and then 2+ seconds. This means that it normally takes 3 exposures in the sequence table for the AEC to be stable. In Flare High mode, it will take 4 exposures to be stable. Note: Because of this stability problem, Loop 3 and Loop 5 must have 3 or 4 observing regions if the number of iterations of Loop3 and Loop 5 is to be greater than 1. If there is only one exposure in the sequence table which is constantly repeated, then the exposure level will cycle up and down around the proper exposure level. If there are four or more exposures in the sequence then each exposure level will be updated properly, without any oscillation or delay. If it is desired to repeat the same exposure every time, it will be necessary to have the sequence table parameters duplicated at least four times. The image readout from SXTE-J buffer to telemetry is sycnronized to the exposure cycle time (the previous image has to be read out before the next one can be taken). AUTOMATIC EXPOSURE CONTROL (AEC) Page 4-6 General Information On AEC 16 December 1989 4.4 General Information On AEC - 1. AEC can be turned on/off for each exposure sequence (each "line" in the sequence tables) 3. Each exposure sequence (each "line" in the sequence table) has its own automatic exposure control data buffer/calculation area which means there should be no conflicts/confusion between separate exposures during calculations. 4. The AEC needs 3-4 exposures (of any exposure type) to see the results of its adjustments. This means that if there is only one expsure in the sequence table, the exposure level will cycle above and below its proper level every 3-4 exposures. (See AEC - Timing Section) 2. If the current exposure is over exposed, the under exposure check is not performed. 5. Use of the 10% mask can be eliminated by specifing AECL to be 2. NOTE: There is only one AECL level for all modes and sequence tables. ??UPDATE?? A different algorithm to inhibit the 10% mask is being developed. 7. The images for ROIs that are composed of multiple PFIs will have the AEC program run on the whole image (even though it takes several exposures). 8. The AEC will be required to perform its calculations on the compressed data. This means that there will be an uneven weighting favoring the higher counts. It is not possible to check HOW over exposed the image is, and adjust the size of the exposure level step accordingly. CHAPTER 5 SXTE-J IMAGE BUFFERS There are two PFI buffers, one FWI buffer, and one patrol image buffer in the SXTE-J. There are backup buffers for each of these primary buffers. It is also possible to redirect the PFI images to the FWI buffer if the need arises. If background subtraction is required for the ARS calculations, the second patrol image buffer will be used for the background image. Partial Frame Image Buffers: The PFI buffers can handle 1024 pixels by 64 lines. Because of timing considerations, only 64 lines can be stored, even if there are only 512 or 256 pixels on the line. The columns to extract are selected after the image has been read into the buffer. New Img Data +---------+ From U-side | | =========>>| PBA | +---------+ +---------+ Old Img Data | | to Telemetry | PBB |=============>> +---------+ If a PFI exposure is missed due to set-up incomplete bit or a patrol image exposure, the old image data is read into the telemetry again. There is data that is more recent in the other buffer, but since a new exposure has not happened, the buffers have not been switched. ST??UPDATE?? The flight model software will (probably?) be modified to not send out the exact same data several times if there is some waiting for the PFI exposure. Instead, a different set of 64 columns will be sent. NO CHAPTER 6 AUTOMATIC ROI TRACKING (ART) 6.1 Introduction - Automatic ROI Tracking tracks the movements of observing regions due to spacecraft attitude drift. Instead of changing the pointing of the telescope, the same function is served by choosing a different part of the CCD image. ART software uses the attitude control fine sun sensor data to maintain pointing (not the HXT sun sensor). The (2) 1-D sun sensors are oriented east/west and north/south. ART will not correct for spacecraft roll. ART will NOT correct for the rotation of the sun. If an active region is being corrected by ART (but ARS is off) and we have day-night-day transition, the ART will correct for any spacecraft drift from the last position it was pointing at. Any change in position due to solar rotation will not be taken into account. ?? Can we define a table that can be used to correct for the solar rotation. The calculations can be done on the ground and uplinked. ?? Will ART work on ROIT 0-3? Even when ARS is on? NO ST?? How often will ART make corrections? Every 16 Major Frames (=32 sec in high rate) [ More information to follow later ] CHAPTER 7 AUTOMATIC ROI RELOCATION (ARR) 7.1 Introduction - Automatic ROI Relocation automatically changes the size of the ROI (ROI mode) to cover entire flaring region when an observed flare excceeds its boundary of field of view (FOV) If the flare gets larger than the FOV being used, ARR can increase the size of the FOV in one of two ways: (1) change the resolution (ie: from 1x1 to 2x2), or (2) change the ROI mode. The general algorithm involves checking the intensity of the pixels on the border of the observing region. [ More information to follow later ] CHAPTER 8 REFERENCE TABLES The following tables are meant to be quick reference tables to determine the time required for different exposures. REFERENCE TABLES Page 8-2 Cycle Time For SXT Exposures 16 December 1989 8.1 Cycle Time For SXT Exposures - Seconds (Minutes) (For FWI it is the buffer readout time) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ High Rate Med Rate Low Rate (32 Kbits/Sec) (4 Kbits/Sec) (1 Kbit/Sec) ~~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~ Flare Mode PFI % 2 16 None --------------------------------------------------------------------- FWI None None None ============================================================================= Quiet Mode SXTFMT=PFI (8:2 PFI:FWI) PFI % 2 16 None --------------------------------------------------------------------- FWI (FWI Mode 0) 1024 (17.1) 8192 (136.5) None (FWI Mode 1) 512 ( 8.5) 4096 ( 68.3) None (FWI Mode 2) 256 ( 4.3) 2048 ( 34.1) None (FWI Mode 3) 128 ( 2.1) 1024 ( 17.1) None ......................................................................... SXTFMT=FWI (2:8 PFI:FWI) PFI % 8 64 None --------------------------------------------------------------------- FWI (FWI Mode 0) 256 ( 4.3) 2048 (34.1) None (FWI Mode 1) 128 ( 2.1) 1024 (17.1) None (FWI Mode 2) 64 ( 1.1) 512 ( 8.5) None (FWI Mode 3) 32 ( 0.5) 256 ( 4.3) None ============================================================================= Night Mode @ None None None ============================================================================= Notes: % PFI times listed here are for ONE ROI (single 64x64 image) @ FWI will continue to be read out of SXTE-J buffer into the BDR at quiet mode rate. Readout for FWI for different FWI Modes (High Telemetry Rate) --------------------------------------------------------------- Mode KBytes_data PFI:FWI 8:2 PFI:FWI 2:8 Lines Out of Camera# Sec (Minutes) Sec (Minutes) 1x1 2x2 4x4 ----------------------------------------------------------------------- 0 512 1024 (17.1) 256 (4.3) 512 1024* 2048* 1 256 512 ( 8.5) 128 (2.1) 256 512 1024* 2 128 256 ( 4.3) 64 (1.1) 128 256 512* 3 64 128 ( 2.1) 32 (0.5) 64 128 256 Notes: #=Different number of lines out is because of HORIZONTAL summing *=cannot get that many lines out for that summation mode. REFERENCE TABLES Page 8-3 Time Interval Between Exposures 16 December 1989 8.2 Time Interval Between Exposures - Time interval between Exposures Seconds (Minutes) High Rate Med Rate (4 KBytes/sec) (0.5 Kbytes/sec) ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~ PFI:FWI PFI:FWI PFI:FWI PFI:FWI 8:2 %% 2:8 8:2 %% 2:8 ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ Single PFI 2 ( 0.03) 8 ( 0.13) 16 ( 0.27) 64 ( 1.07) 4 PFIs 8 ( 0.13) 32 ( 0.53) 64 ( 1.07) 256 ( 4.27) 16 PFIs 32 ( 0.53) 128 ( 2.13) 256 ( 4.27) 1024 ( 17.07) 32 PFIs 64 ( 1.07) 256 ( 4.27) 512 ( 8.53) 2048 ( 34.13) FWI - Mode 0 1024 ( 17.07) 256 ( 4.27) 8192 (136.53) 2048 ( 34.13) FWI - Mode 1 512 ( 8.53) 128 ( 2.13) 4096 ( 68.27) 1024 ( 17.07) FWI - Mode 2 256 ( 4.27) 64 ( 1.07) 2048 ( 34.13) 512 ( 8.53) FWI - Mode 3 128 ( 2.13) 32 ( 0.53) 1024 ( 17.07) 256 ( 4.27) NOTE: (a) %% Flare mode is PFI:FWI 8:2, and there is no FWI %% (b) There is no data in the low rate (1 Kbit/sec), and no data in night mode (FWI will continue to be read out of SXTE-J buffer into the BDR at the quiet mode rate. REFERENCE TABLES Page 8-4 Number Of Images That Can Be Taken In One Orbit (60 Minutes) 16 December 1989 8.3 Number Of Images That Can Be Taken In One Orbit (60 Minutes) - High Rate Med Rate (4 KBytes/sec) (0.5 Kbytes/sec) ~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~ PFI:FWI PFI:FWI PFI:FWI PFI:FWI 8:2 %% 2:8 8:2 %% 2:8 ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ Single PFI 1800.0 && 450.0 && 225.0 56.3 4 PFIs 450.0 && 112.5 && 56.3 14.1 16 PFIs 112.5 && 28.2 && 14.1 3.5 32 PFIs 56.3 && 14.1 && 7.0 1.8 FWI - Mode 0 3.5 && 14.1 && 0.4 1.8 FWI - Mode 1 7.0 && 28.2 && 0.9 3.5 FWI - Mode 2 14.1 && 56.3 && 1.8 7.0 FWI - Mode 3 28.2 && 112.5 && 3.5 14.1 NOTE: (a) && The BDR only has a capacity of 41.7 minutes, not 60 minutes. See the next table to see the actual number of images that can be taken. (b) %% Flare mode is PFI:FWI 8:2, and there is no FWI %% 8.4 Number Of Images To Fill The BDR - PFI:FWI PFI:FWI 8:2 %% 2:8 ~~~~~~~~~~~~~ ~~~~~~~~~~~~~ Single PFI 1280.0 320.0 4 PFIs 320.0 80.0 16 PFIs 80.0 20.0 32 PFIs 40.0 10.0 FWI - Mode 0 2.5 10.0 FWI - Mode 1 5.0 20.0 FWI - Mode 2 10.0 40.0 FWI - Mode 3 20.0 80.0 NOTE: BDR Capacity is assumed to be 83,886,080 bits. The BDR will be filled up in 42.66 minutes at the high rate, and 341.33 minutes (5.7 hours) at the medium rate. REFERENCE TABLES Page 8-5 Different Telemetry Rates 16 December 1989 8.5 Different Telemetry Rates - Telemetry Rate High Med Low - BPS (Bits/Sec) 32,786 4,096 1,024 - Bytes/Sec 4,096 512 128 ------------------------- ------ ------ ------ Minor Frame Period (Sec) 0.031 0.250 1.000 Major Frame Period (Sec) 2.0 16.0 64.0 SXT Data Rate (bytes/Sec) Sect-1: 2*8 bytes/minor frame 512 64 16 Sect-2: 8*8 bytes/minor frame 2048 256 64 Quiet Data Rate (Sect 1+2) 2560 384 82 Flare Data Rate (Sect 2) 2048 256 64 Note: There are 64 minor frames per major frame. In Quiet Mode, SXT gets 62.5% of telemetry stream. In Flare Mode, SXT gets 50.0% of telemetry stream. Quiet Mode = 2*8 + 8*8 bytes/minor frame rate Flare Mode = 8*8 bytes/minor frame rate REFERENCE TABLES Page 8-6 Different Fields Of View For ROIs 16 December 1989 8.6 Different Fields Of View For ROIs - The following is a table which defines the field of view of the different shaped Regions of Interest. A ROI is defined by specifying the number of PFIs in the east/west direction (N) and then number in the north/south direction (M). Field of View (in one dimension) (arcMin) Summation N or M 1x1 2x2 4x4 ------ ------------------------------------------ 1 2.6 5.2 10.4 2 5.2 10.4 20.8 3 7.8 15.6 31.2 4 10.4 20.8 41.6 5 13.0 26.0 N/A 6 15.6 31.2 N/A 7 18.2 36.4 N/A 8 20.8 41.6 N/A 9 23.4 N/A N/A 10 26.0 N/A N/A 11 28.6 N/A N/A 12 31.2 N/A N/A 13 33.8 N/A N/A 14 36.4 N/A N/A 15 39.0 N/A N/A 16 41.6 N/A N/A REFERENCE TABLES Page 8-7 SXT Part Of Telemetry Data Block In One Minor Frame 16 December 1989 8.7 SXT Part Of Telemetry Data Block In One Minor Frame - Flare mode: 0 1 2 3 4 5 6 7 8 9 A B C D E F +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | W | B | | | | Basic Data | B | C | HXT | SXT | | | S | S | | | | | | | | | | | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ Quiet mode: 0 1 2 3 4 5 6 7 8 9 A B C D E F +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | W | B | | | | Basic Data | B | C | SXT | SXT | | | S | S | #1 | #2 | | | | | | | | | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ FWI PFI ---------- ---------- Flare Mode 8:15 (8x8) None Quiet Mode SXTFMT=PFI (8:2 PFI:FWI) 6:7 (2x8) 8:15 (8x8) SXTFMT=FWI (2:8 PFI:FWI) 8:15 (8x8) 6:7 (2x8) Night Mode None None Note: N:M specifies the starting and ending columns for the SXT data. There are 16 columns and 8 lines available for each minor frame block. (NxM) specifies the number of "columns" N by "lines" M for each minor frame block (128 byte blocks). There are 64 minor frames per major frame. REFERENCE TABLES Page 8-8 Sample PFI SEQ Table 16 December 1989 8.8 Sample PFI SEQ Table - Number of iterations for Loop 2 = 1 Loop 3 = 1 Loop 4 = 1 Loop 5 = 1 Flsh Sht F#0 F#1 F#2 A- DPE DIF Res ROIT Alt Alt AEC AEC AEC AEC AEC B/A B/A Door Lev ULT LLT UAT LAT ---- --- --- --- --- -- --- --- --- ---- --- --- --- --- --- --- --- 1-1 NOP 2-1 NOP 2-2 NOP 3-1 44h M 2/1 2/3 2/5 Op 6 Off FC-1 0 On 0 On 70 40 100 100 3-2 44h M 3/1 3/3 3/5 Op 6 Off FC-1 1 On 0 On 70 40 100 100 3-3 44h M 4/1 - - Op 6 Off FC-1 2 Off 0 On 70 40 100 100 3-4 44h M 5/1 - - Op 6 Off FC-1 3 Off 0 Off - - - - 4-1 NOP 4-2 NOP 5-1 44h M 2/3 2/4 2/6 Op 4 Off HC-1 0 On 0 On 70 40 100 100 5-2 44h M 3/3 3/4 3/6 Op 4 Off HC-1 1 On 0 On 70 40 100 100 5-3 44h M 4/3 - - Op 4 Off HC-1 2 Off 0 On 70 40 100 100 5-4 44h M 5/3 - - Op 4 Off HC-1 4 Off 0 Off - - - - Key === Flsh = Flush count Sht = Shutter Mode F#0 = Filter B/A #0 F#1 = Filter B/A #1 F#2 = Filter B/A #2 A-Door = Aspect Door Position [ Op(en) / Cl(osed) ] DPE = SXTE-J/DP Exposure Level DIF = Dark Image Flag [ Off = no dark image ] Res = Resolution/Compression - # of ROI [ F(ull), H(alf), Q(uarter) ] [ C(ompressed), L(ow), H(igh) ] ROIT = ROI Table Number Alt = Alternation Enable [ On = enabled ] Alt Lev = Alternation Level (starting Alternation level) AEC = AEC Enable [ On = enabled ] AEC ULT = AEC Upper Limit Threshold (data counts) AEC LLT = AEC Lower Limit Threshold (data counts) AEC UAT = AEC Upper Area Threshold (# of pixels) AEC LAT = AEC Lower Area Threshold (# of pixels) NOTE: The 10% mask was assumed to be filter 2 on wheel A REFERENCE TABLES Page 8-9 Sample ROI Table 16 December 1989 8.9 Sample ROI Table - ROI Table Mode of ROI Row Center Address Column Center Address --------- ----------- ------------------ --------------------- 0 00 hex - - 1 11 hex - - 2 11 hex - - 3 14 hex - - 4 22 hex 0 0 5 00 hex 0 0 6 41 hex 0 0 7 44 hex 0 0 8.10 Sample EXPDT Table - EXPDT Table Alternate Filter Combination (A/B) DPE Expos Lev ----------- ---------------------------------- ------------- 0 1/2 6 1 3/4 6 2 5/2 6 3 2/2 6 4 5/3 6 5 1/3 6 6 7 8.11 Sample Common Table Values - DPE Upper Limit = 10 DPE Lower Limit = 0 Exposure level step size = 1 ARS turned on REFERENCE TABLES Page 8-10 Sample FWI SEQ Table 16 December 1989 8.12 Sample FWI SEQ Table - Number of iterations for Loop 2 = 1 Loop 3 = 1 Loop 4 = 1 Loop 5 = 1 Flsh Sht Flt A- DPE DIF Res ROI ROI ROI ROI ROI ROI ROI ROI FWI BLS Door 1St 1W 2St 2W 3St 3W 4St 4W Mode ---- --- --- -- --- --- --- --- --- --- --- --- --- --- --- ---- --- 1-1 NOP 2-1 NOP 2-2 NOP 3-1 44h M 1/1 Op 6 Off FC-1 0 64 - - - - - - 1 Off 3-2 44h M 3/3 Op 4 Off HC-1 0 255 - - - - - - 1 Off 3-3 44h M 6/6 Op 2 Off QC-1 0 255 - - - - - - 3 Off 3-4 NOP 4-1 NOP 4-2 NOP 5-1 44h M 1/1 Op 6 Off FC-2 0 32 128 32 - - - - 1 Off 5-2 44h M 3/3 Op 4 Off HC-1 0 255 - - - - - - 1 Off 5-3 44h M 6/6 Op 2 Off QC-1 0 255 - - - - - - 3 Off 5-4 NOP Key === Flsh = Flush count Sht = Shutter Mode [ M(echanical) / F(rame) T(ransfer) ] Flt = Filter B/A A-Door = Aspect Door Position [ Op(en) / Cl(osed) ] DPE = SXTE-J/DP Exposure Level DIF = Dark Image Flag [ Off = no dark image ] Res = Resolution/Compression - # of ROI [ F(ull), H(alf), Q(uarter) ] [ C(ompressed), L(ow), H(igh) ] ROI 1St = ROI 1 commanded start line (actual line is 4 times commanded line) ROI 1W = ROI 1 commanded width ROI 2St = ROI 2 commanded start line (actual line is 4 times commanded line) ROI 2W = ROI 2 commanded width ROI 3St = ROI 3 commanded start line (actual line is 4 times commanded line) ROI 3W = ROI 3 commanded width ROI 4St = ROI 4 commanded start line (actual line is 4 times commanded line) ROI 4W = ROI 4 commanded width FWI Mode= FWI Mode (0=512K, 1=256K, 2=128K, 3=64K) BLS = BLS columns read out or not CHAPTER 9 GUIDELINES FOR SPECIAL OBSERVING SEQUENCES Some of the descriptions of these special observing sequences use information that is described in appendix A. GUIDELINES FOR SPECIAL OBSERVING SEQUENCES Page 9-2 Movies 16 December 1989 9.1 Movies - * There should be no periodic patrol images and no patrol images at mode changes. * The entry table should point to the same PFI sequence table for both Quiet and Flare modes. * It might be desirable to inhibit the flare trigger (stay in Quiet mode), or to force the DP into Flare mode to avoid mode change problems. * For the high speed movies (0.5 and 1.0 second cycle times), there can only be a single observing region. There are also limits on the exposure level, and ART might have to be disabled. GUIDELINES FOR SPECIAL OBSERVING SEQUENCES Page 9-3 One Patrol Image Per Orbit 16 December 1989 9.2 One Patrol Image Per Orbit - GUIDELINES FOR SPECIAL OBSERVING SEQUENCES Page 9-4 One Patrol Image Per Mode Change 16 December 1989 9.3 One Patrol Image Per Mode Change - GUIDELINES FOR SPECIAL OBSERVING SEQUENCES Page 9-5 Only One Full Width Image Per Orbit 16 December 1989 9.4 Only One Full Width Image Per Orbit - * It will be necessary to have two FWI sequence tables: FWI SEQ table A -has a single exposure FWI SEQ table B -has no exposures in it (full of NOPs) * The entry table will be initially set to use FWI SEQ A. * The OG used for the day mode transition will need to start a different OG? (from the OP?) * The OG will have to: 1. Wait until the FWI has been taken (and read out of the buffer?) 2. Optionally change SXTFMT from 2:8 PFI:FWI to 8:2 3. Make a change to the entry table, telling the table to use FWI SEQ table B. 4. Trigger the SXTE-J/DP to look at the entry table again? CHAPTER 10 SPECIFYING OBSERVATIONS The following chapter is meant to be used as a guide line to specifying observations. There are some references to what the other instruments should be doing. 10.1 Parameters That Need To Be Specified - SPECIFYING OBSERVATIONS Page 10-2 Parameters That Need To Be Specified 16 December 1989 10.1.1 Sample "Worksheet" For Defining Sequences - DP/Common Table Parameters: Flare Flag Automatic/Manual: ______ If manual: DP Mode: ______ Telemetry rate: ______ If automatic: Detector - SXS/HXS/(SXS or HXS) ______ What level of counts to use? ______ BCS-OUT at end of flare? ______ BCS-OUT at start of night? ______ SXTFMT (2:8 or 8:2 PFI:FWI): ______ ARS on/off: ______ Patrol image filter: ______ SXT: ** PFI Mode ** Cadence: ______ Number of ROIs: ______ Filters: ______ Field of View: ______ Exposure (level or AEC): ______ ART on/off: ______ ** FWI Mode ** Cadence: ______ Number of FWIs: ______ Filters: ______ Field of View: ______ Exposure (level) ______ BCS: Fe XXVI On/Off - Binning: ______ Fe XXV On/Off - Binning: ______ Ca XIX On/Off - Binning: ______ S XV On/Off - Binning: ______ HXT: No parameters to vary? WBS: No parameters to vary? SPECIFYING OBSERVATIONS Page 10-3 Parameters That Need To Be Specified 16 December 1989 10.1.2 Full Description Of SXT Sequence Table Parameters - PFI Mode: ========= Resolution (on chip summation): 1x1 - F - Full (2.4") 2x2 - H - Half (4.9") 4x4 - Q - Quarter (9.8") Shape of ROI: NxM PFIs Which ROI to use: 1-8 Filters: A: OPN, TN1, MED, TK1, TK2, TN2 B: OPN, 10M, OP1, DIF, TN3, OP2 AEC On/Off: On/Off Exposure Level: ? NOTE: The field of view is determined by the ROI. If AEC is on, there it is still necessary to specify a starting default exposure level when loading the sequence table. FWI Mode: ========= Resolution (on chip summation): 1x1 - F - Full (2.4") 2x2 - H - Half (4.9") 4x4 - Q - Quarter (9.8") Number of LOIs: 1-4 Location of LOIs: X,Y Filters: A: OPN, TN1, MED, TK1, TK2, TN2 B: OPN, 10M, OP1, DIF, TN3, OP2 Exposure Level: ? 10.1.3 Full Description Of BCS Parameters - Which channels to use: Fe XXVI, Fe XXV, Ca XIX, S XV Binning factor for each channel: 1-? (1 is no binning = full resolution) SPECIFYING OBSERVATIONS Page 10-4 Sample Observation Sequence 16 December 1989 10.2 Sample Observation Sequence - This section is an example of how to define an experment. The experment is: MEASUREMENT OF THE "SUPERHOT" COMPONENT IN FLARES (JRL/KTS - August 1988) 10.2.1 Science Objectives - One of the most interesting discoveries from Solar Cycle 21 is that there is a "superhot" component present during the impulsive phase of the flare. This "superhot" component has a temperature in excess of 30MK, and can be infered from the presence strong Fe XXVI emission, as was observed by Hinotori or an excess of hard X-ray emission below 50 keV (Linn balloon results). Little is known about the origins or importance of this component to the flare procss. A number of interesting questions can be answered by the unique combination of observations obtainable by the instruments on Solar-A, for example: 1) What is the location and extent of the "superhot" plasma? 2) Is it energetically significant? 3) Is the Superhot source moving? 4) Why do only some flares have superhot components? This experiment is designed to look at the first three of these questions on a flare by flare basis. To address the forth question one would have to observe a large number of events with this or similar sequences. The BCS and WBS will provide information on the mass motions, overall emission measure and mean temperatures. HXT and SXT will provide data on the translational motions and location of the "superhot" plasma. To find the location and extent of the "superhot" component we have to show at each pixel whether there is a "superhot" component present, hence this experiment requires good temperature diagnostics as well as good time resolution. We should also have pre- and post-flare magnetograms to help understand the magnetic configuration of the region during the event. The Solar-A instruments will have to get a well coordinated set of observations. This is especially true during the very earliest phases of the flare where getting every instrument into the flare mode as soon as possible will determine the success of the experiment. 10.2.2 Observational Objectives - 1) Determine pre-flare conditions (SXT,WBS,B) 2) Determine site and time of initial energy release (HXT,SXT,WBS) 3) Determine DEM as a function of time and location throughout the impulsive phase of the flare (BCS,SXT,WBS,HXT) 4) Determine line-of-sight and translational velocities (BCS,SXT) 5) Follow development of flare through gradual phase (SXT,BCS,WBS) SPECIFYING OBSERVATIONS Page 10-5 Sample Observation Sequence 16 December 1989 6) Determine post-flare B field (B) (N.B. "B" stands for magnetograph observations required) 10.2.3 Assumptions/Actions: - Pre-Flare assumptions/actions: Location: Anywhere on Sun (pref. on disk) GOES Flare Level: >M1, trigger Flare Flag at C1 level Time Scales: mins - 1 hour Other: Candidate region identified Quicklook or Ground-based data 10.2.4 Overview Of Actual Sequence (filling In Worksheet) - 10.2.4.1 Pre-Flare Sequence - 10.2.4.2 Flare Sequence - 10.2.4.3 Flare Decay Sequence - 10.2.5 SXT Timeline/Table Of The Sequence - SPECIFYING OBSERVATIONS Page 10-6 Sample Observation Sequence 16 December 1989 10.2.5.1 Pre-Flare Sequence - ============================================================================== SXT Mode: PFI DP Mode: Quiet Rate: High SXTFMT: 2:8 PFI:FWI ------------------------------------------------------------------------------ Exp Time Major ROI# ROI ROI Filter Expos Comments # (sec) Frame Shape sum ------------------------------------------------------------------------------ 0 0 0 - - - - Wait for stability - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 120 60 1 1x1 1x1 TN1 AEC 2 128 64 1 1x1 1x1 MED AEC 3 136 68 1 1x1 1x1 TK1 AEC 4 144 72 1 1x1 1x1 OP2 AEC - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Repeat 1-4 until flare flag or night - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3600 1800 - - - - Spacecraft night ============================================================================== ============================================================================== SXT Mode: FWI DP Mode: Quiet Rate: High SXTFMT: 2:8 PFI:FWI ------------------------------------------------------------------------------ Exp Time Major ROI# Mode Filter Expos Comments # (sec) Frame of FWI ------------------------------------------------------------------------------ 0 0 0 - - - - Wait for stability - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 120 60 1 0 TN1 AEC X-Ray Survey 2 376 188 1 0 OP2 AEC Alignment Image - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Repeat 1-2 until flare flag or night - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3600 1800 - - - - Spacecraft night ============================================================================== SPECIFYING OBSERVATIONS Page 10-7 Sample Observation Sequence 16 December 1989 10.2.5.2 Flare Sequence - ============================================================================== SXT Mode: PFI DP Mode: Flare Rate: High SXTFMT: 8:2 PFI:FWI (no FWI) ------------------------------------------------------------------------------ Exp Time Major ROI# ROI ROI Filter Expos Comments # (sec) Frame Shape sum ------------------------------------------------------------------------------ n t f 1 1x1 1x1 TN1 AEC n+1 t+2 f+1 1 1x1 1x1 MED AEC n+2 t+4 f+2 1 1x1 1x1 TK1 AEC n+3 t+6 f+3 1 1x1 1x1 TK2 AEC n+4 t+8 f+4 1 1x1 1x1 TN2 AEC n+5 t+10 f+5 1 1x1 1x1 OP2 set - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Repeat (n)-(n+5) until no great flare flag AND end of minimum flare duration ============================================================================== SPECIFYING OBSERVATIONS Page 10-8 Sample Observation Sequence 16 December 1989 10.2.5.3 Flare Decay Sequence - ============================================================================== SXT Mode: PFI DP Mode: Flare Rate: Medium SXTFMT: 8:2 PFI:FWI (no FWI) ------------------------------------------------------------------------------ Exp Time Major ROI# ROI ROI Filter Expos Comments # (sec) Frame Shape sum ------------------------------------------------------------------------------ n' t' f' 1 2x2 1x1 TN1 AEC n'+1 t'+64 f'+4 1 2x2 1x1 MED AEC n'+2 t'+128 f'+8 1 2x2 1x1 TK1 AEC n'+3 t'+192 f'+12 1 2x2 1x1 OP2 set - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Repeat (n')-(n'+3) until no flare flag ============================================================================== APPENDIX A SOLAR-A DP INDEPENDENT OF SXTE-J The following sections contain DP information that is relavent to the operation of the SXT but which SXT has no direct control over. SOLAR-A DP INDEPENDENT OF SXTE-J Page A-2 Introduction 16 December 1989 A.1 Introduction - A.1.1 Different Modes And Rates - There are different DP modes that are relavant to observing: Flare (FL) Quiet (QT) BCS-OUT (BCS) Night (NT) There are also different telemetry rates (high, medium, and low). The modes that are of most relevance are: Flare - High Flare - Med Quiet - High Quiet - Med The DP Mode Control can be automatic or manual. The Flare Control can be automatic or manual. When there is a ground link with KSC, the DP will be commanded into high mode. There is no command to only change the mode so KSC will have to first check which mode the DP is in and then send the command (the manual commands for rate include commanding the DP mode). If it is necessary to change the DP rate, the DP Mode Control will have to be set to manual. <> What does that mean about flares that occur during downlinks - Lost? A.1.2 Different Sub-systems - Subsystems Power Supply System SCP - Solar Cell Paddle BAT-A/B - Battery PCU - Power Control Unit CNV - Converter DIST - Distributor SHNT - Shunt Resister Communications System XANT - X-Band Antenna SANT - S-Band Antenna SSW - S-Band Antenna Switch XSW - X-Band Antenna Switch SDIP - S-Band Diplexer SBR - S-Band Receiver SOLAR-A DP INDEPENDENT OF SXTE-J Page A-3 Introduction 16 December 1989 TMS - S-Band Transmitter TMX - X-Band Transmitter Command and Data Handling System CMD - Command Decoder TCU - Telemetry Command Control Unit DP - Data Processor BDR - Bubble data recorder HK - House Keeping Attitude Control System IRU - Inertial Reference Unit GAS - Geomagnetic Aspect Sensor TFSS - Two Dimensional Fine Sun Sensor NSAS - Non Spin Type Sun Sensor STT - Star Tracker MW-A/B WDE-A/B - Momentum Wheel / Wheel Drive Electronics MTQ - Magnetic Torquer CMG - Controlled Momentum Gyro ACE - Attitude Control Electronics ACP - Attitude Control Processor Scientific Instruments HXT - Hard X-ray Telescope SXT - Soft X-ray Telescope BCS - Bragg Crystal Spectrometer WBS - Wide Band Spectrometer WBS-SXS - WBS Soft X-ray Spectrometer PC## = Pulse Counter, ## = energy channel PH## = Pulse Height Data, ## = energy channel WBS-HXS - WBS Hard X-ray Spectrometer PC## = Pulse Counter, ## = energy channel PH## = Pulse Height Data, ## = energy channel WBS-GRS - WBS Gamma Ray Spectrometer GBD - Gamma Ray Burst Detector SOLAR-A DP INDEPENDENT OF SXTE-J Page A-4 Introduction 16 December 1989 A.1.3 Scientific Instruments - HXT SXT BCS WBS SXS HXS GRS Energy Range: 15- 25 0.1-3 S XV 2-30 10-400 0.2-100 25- 40 KeV Ca XIX KeV KeV MeV 40- 70 Fe XXV 70-100 Fe XXVI KeV Energy Res: ---- ---- ---- PH 128 32 128+16 PC 2 2 4+2 channels channels channels Spatial Res: <8" FWHM <2" #1 none none none none Field of View: 40'x40' 42'x42' Whole Whole Whole Whole #3 Sun Sun Sun Sun Spectal Res: ---- ---- #2 ---- ---- ---- Time Res: 0.5 sec <1 sec ~1 sec PC = PC = PC = 250 msec 125 msec 250 msec PH = PH = PH = 2 sec 1 sec 4 sec NOTES: #1: over 60% of the field of view #2: wavelength/delta_wavelength = 3000 to 6000 #3: fields of view are variable, minimum field of view possible 2.6'x2.6' #4: PH = Pulse Height PC = Pulse Counter HXT - Fourier Synthesis telescope with 64 small modulation collimator Simultaneous images at selected energies between 10 and 100 KeV Absolute position determination better than 3" SXT - Wolter I X-Ray telescope with 1024x1024 CCD Continuous operation before/during/after the start of each flare BCS - Four bent crystals, 1-D detectors SOLAR-A DP INDEPENDENT OF SXTE-J Page A-5 Telemetry 16 December 1989 A.2 Telemetry - There are three different telemetry rates. These telemetry rates are the on board telemetry rates (the rates that data is written to the bubble data recorder (BDR)), not the telemetry rate to the ground. Telemetry Rate High Med Low - BPS (Bits/Sec) 32,786 4,096 1,024 - Bytes/Sec 4,096 512 128 ------------------------- ------ ------ ------ Minor Frame Period (Sec) 0.031 0.250 1.000 Major Frame Period (Sec) 2.0 16.0 64.0 A.2.1 Launch Information And The Orbit - Inclination = 31 Degrees Launch Info Rocket: ISAS (Japanese) M3-SII Location: KSC Date: Aug-Sept '91 A.2.2 Ground Link - KSC (Kagoshima Space Center) ---------------------------- 1, 4, 32, or 131 KBPS (S-Band) (1,4,32 are for real time telemetry) 262 KBPS (X-Band) - BDR dump only DSN (NASA Deep Space Network) ----------------------------- 262 KBPS (S-Band) - BDR dump only 15 orbits a day (24 hours) 5 orbits a day we have KSC contact (they are all in a row) It takes 5 minutes, 20 seconds to read the BDR using high rate (X-band) It takes 10 minutes, 40 seconds to read the BDR using low rate (S-band) The following is an example of 15 orbits (the last 5 orbits are listed as A-E in hexidecimal notation). SOLAR-A DP INDEPENDENT OF SXTE-J Page A-6 Telemetry 16 December 1989 D N D N D N D N D N D N D N D N D N D N D N D N D N D N D N a g a g a g a g a g a g a g a g a g a g a g a g a g a g a g y t y t y t y t y t y t y t y t y t y t y t y t y t y t y t 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 A A B B C C D D E E --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Example 1: G G G G G Example 2: G G G G G Example 3: G G G G G Example 3: G G G G G G == ground link Example 1: The ground link occurs solely during the spacecraft night KSC: Night mode data (BCS-OUT or GBD data) real time S-Band The BDR is read out using the X-Band DSN: Real time data is lost The BDR is read out using the S-Band Real time data using S-Band after finished reading out BDR Example 2: The ground link occurs solely during the spacecraft day KSC: The real time data is sent down using the S-band The BDR is read out using the X-Band DSN: Real time data is lost The BDR is read out using the S-Band Real time data using S-Band after finished reading out BDR Example 3: The ground link occurs during the spacecraft night, but the spacecraft goes into day during the link. KSC: The real time data is sent down using the S-band The BDR is read out using the X-Band DSN: Real time data is lost The BDR is read out using the S-Band Real time data using S-Band after finished reading out BDR Example 4: The ground link occurs during the spacecraft day, but the spacecraft goes into night during the link. KSC: The real time data is sent down using the S-band The BDR is read out using the X-Band DSN: Real time data is lost The BDR is read out using the S-Band Real time data using S-Band after finished reading out BDR A.2.3 Options When There Are Transmission Problems - The BDR is automatically "erase" at the completion of the readout (the S/C does not wait for the ground to confirm receipt). KSC can disable erasing of the BDR by sending a STOP command before the BDR is completely read out. The next orbit of data would only be saved if the priority of the new data was SOLAR-A DP INDEPENDENT OF SXTE-J Page A-7 Telemetry 16 December 1989 higher than the BDR data. KSC can also send a command to disable all writes to the BDR regardless of the priority of the new data. A.2.4 Deep Space Network (DSN) - There is no confirmation that DSN stations are listening when the BDR is read out to the DSN stations. Timed commands (OP command) are stored in the S/C which tell it when to execute a BDR dump. Only S-Band can be used with the DSN (BDR dump in 5 minutes). This means that we will lose all real time data during DSN downlinks (when it is a spacecraft day) If there is time after reading the BDR, the real time data will be sent to the DSN station. <> S-Band should take 10 minutes, is it shorter because of different encoding? The downlinks to the DSN stations (Madrid, Cambarra, Goldstone) <> It seems that an option to not erase the data after a DSN downlink would be nice. Example: Great Flare data that would be read down to the DSN. This is partially risky? and at a minimum, everyone at ISAS would like to see that data ASAP. DSN data will take weeks to get to ISAS. A.2.5 Visibile VS Invisible Orbits - Visible orbit - with telemetry downlink (send down real time data AND the BDR data) Invisible orbit - without telemetry downlink In example 1 above, the visibile orbits are 6,7,8,9, and A. <> There is some confusion about whether a visible orbit is an orbit where there is a KSC downlink or whether it means that only one orbit has occured since the last downlink. A.2.6 Successive Ground Links After Only One Orbit (SGLOOO) - On average there are 15 orbits per 24 hours, and 5 visible orbits. For 4 of the 5 ground links there is only one orbits worth of data in the BDR. For SOLAR-A DP INDEPENDENT OF SXTE-J Page A-8 Telemetry 16 December 1989 the other orbit, there is 10 orbits of data in the BDR!! Successive Ground Links after Only One Orbit (SGLOOO) - when the BDR has only one orbits worth of data written to it because of ground links. In example 1 above, SGLOOOs are 7,8,9, and A. Even though orbit 6 has a ground link, the BDR has been filled with data from several orbits. It is possible to get 50 minutes of high rate data during SGLOOO 40 minutes of BDR and 10 minutes of real time data. A.2.7 Frame Formats - 128 bytes per minor frame. 64 minor frames make up one major frame (8192 bytes/major frame). The minor frames are defined as 16 columns by 8 rows. Word 0 is in the upper left of the figure below; word 15 is in the upper right; word 127 is in the lower right. Flare mode: 0 1 2 3 4 5 6 7 8 9 A B C D E F +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | W | B | | | | Basic Data | B | C | HXT | SXT | | | S | S | | | | | | | | | | | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ Quiet mode: 0 1 2 3 4 5 6 7 8 9 A B C D E F +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | W | B | | | | Basic Data | B | C | SXT | SXT | | | S | S | #1 | #2 | | | | | | | | | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ SOLAR-A DP INDEPENDENT OF SXTE-J Page A-9 Telemetry 16 December 1989 BCS mode: 0 1 2 3 4 5 6 7 8 9 A B C D E F +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | W | | | | Basic Data | B | (Void) | BCS | | | S | | | | | | | | | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ Night mode: 0 1 2 3 4 5 6 7 8 9 A B C D E F +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | | | Basic Data | GBD | | | | | | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ GBD is Gamma Ray Burst Detector NOTE: When in Quiet mode, if there either the PFI or FFI table is full of NOPs, then the telemetry block that it is supposed to write its data to SXT (1) or SXT (2) is filled with "55"s. A.2.8 Timing Of Telemetry Rate Change - There are two different modes in which a telemetry rate change can occur. A.2.8.1 Slow Case (Non-Emergency) - When there is not a need to change the mode quickly. For non-emergency cases the telemetry rate is changed at a timing of major frame start (for the slowest rate). For example: High --> Low at a timing of SFE clock (once every 64 sec) Med --> Low " Low --> Med " Low --> High " High --> Med at a timing of SFC clock (once every 16 sec) Med --> High " SOLAR-A DP INDEPENDENT OF SXTE-J Page A-10 Telemetry 16 December 1989 A.2.8.2 Fast Cases - When there is a need to change the mode quickly. Fast cases are when a flare occurs. NOTE: If you interupt the previous mode, you can lose data. For emergency cases, a quick change from med or low to high rate is made. Low --> High at a timing of FF clock (once every 2 sec) Med --> High " (See Fujitsu document SLA-SD006 (Version 2, 8-Mar-88, pp 34-37) SOLAR-A DP INDEPENDENT OF SXTE-J Page A-11 Automatic Control Of Observing Mode 16 December 1989 A.3 Automatic Control Of Observing Mode - A.3.1 Basic Principles - A.3.1.1 Philosophy - 1. Of primary importance is the recording of as large a number of flares as possible. 2. A major flare should be preferentially recorded compared to a minor flare. 3. When possible, a flare should be recorded until its end. The following were the guidelines used when determining the algorithm. 1. In general, a larger flare lasts longer than a smaller flare. 2. A flare shows rapid variations in its early phase. The variablility is not as large towards the end of the flare. A.3.1.2 Basic Algorithm - There are several threshold values contained in a "flare-judgement table" in the DP software. For each item in the table (NFT for example) there is a "level table". These values can be modified from the ground. There are four levels available for most items. The DP is told which one of these values to use. The different flare judgement items are: Flare Detection Sensor - instrument/detector Normal Flare Threshold (NFT) - counts/sec Great Flare Threshold (GFT) - factor Flare End Threshold (FET) - fraction RBM Veto Threshold - counts/sec Flare Mode Minimum Duration - minutes (from a table) Preflare Duration - BDR blocks 1. When the flare trigger occurs, the DP goes into Flare-High mode. 2. After a certain amount of time, the DP checks to see if the flare is still occuring. A. If the flare flag is still active, the telemetry rate is changed to medium. The DP continues to check the flare flag periodically. B. When the flare flag finally goes inactive, the DP changes the mode back to quiet. The flare sensor can be one of the following sensors. 1. HXS SOLAR-A DP INDEPENDENT OF SXTE-J Page A-12 Automatic Control Of Observing Mode 16 December 1989 2. SXS 3. BCS The sensors are enabled or disabled. If more than one sensor is enabled, then "OR" logic is used for to trigger the start of a flare and "AND" logic is used to tigger the end of the flare. For example, if all three sensors are enabled, then the following would be true: (HXS "OR" SXS "OR" BCS) - for start of flare (HXS "AND" SXS "AND" BCS) - for end of flare BCS has it's own parameters/criteria to determine flares where the HXS and SXS instruments use the threshold intensity to decide if a flare is occuring. BCS trigger by itself will always be a "normal flare" level. Not possible to use different sensors for start and end A.3.1.3 When The Different Modes/Rates Are Used - The following are the possible conditions that would result in the different modes and telemetry rates when the DP is in the automatic mode. If the DP is in manual, the ground can command whatever DP mode and rate it desires. Flare - High 1. Great Flare Flag is active 2.a. Normal Flare Flag is active (and) b. Flare minimum duration has not been exceeded Flare - Med 1.a. Normal Flare Flag is active (Great Flare Flag is inactive) (and) b. Flare minimum duration has been exceeded Quiet - High 1.a. Normal Flare Flag is inactive (and) b. A Visible Orbit is occuring (real time link) 2.a. Normal Flare Flag is inactive (and) b. A ground link occured on the last orbit (and) c. The current/next orbit will have a ground link (SGLOOO) NOTE: The rate to be used when in quiet mode is determined by ground commands or with operational programs (OPs) There are no "automatic" changes in rate when in Quiet mode. An OP will be set up to change QT/Med to QT/Hi for visible orbits to get a full 60 minutes of data. SOLAR-A DP INDEPENDENT OF SXTE-J Page A-13 Automatic Control Of Observing Mode 16 December 1989 SOLAR-A DP INDEPENDENT OF SXTE-J Page A-14 Automatic Control Of Observing Mode 16 December 1989 A.3.2 Observation Mode Change Logic For Flares - There are two tasks associated with changing the observation mode the Flare mode. 1. Flare Alarm Task (run once / 1 second) 2. Mode Change Task (run once / 2 seconds) A.3.2.1 Flare Alarm Task - The following is the logical flow for the flare alarm task 1. Is "Mode Control" Automatic or Manual? Automatic Manual ========= ====== 2. Flare Judge Logic program 3. Update a table accordingly Update a table from the ground -Flare Flag On/Off -Flare Flag On/Off -Flare Normal/Great -Flare Normal/Great -RBM Flag On/OFF -RBM Flag On/OFF A.3.2.2 Mode Change Task - The following is the logical flow for the mode change task 1. Is "Mode Control" Automatic or Manual? Automatic Manual ========= ====== 2. Read the table Set the mode from the ground (written to by flare alarm task) 3. Activate new mode Activate new mode (if necessary) (if necessary) A.3.3 Flare Trigger - SOLAR-A DP INDEPENDENT OF SXTE-J Page A-15 Automatic Control Of Observing Mode 16 December 1989 Intensity ^ | | * | * * | * * | ---- * -- ** --- Great Flare | * ** Threshold | * *** | * *** | * ** | * **** | * *** | --- * --- Normal Flare ***** | *! Threshold ! ****** | *! ! --- ***** --- Flare End | * ! ! ***** Threshold |***** ! ! **** | !<------ Flare Mode ------>! | ! Minimum Duration ! +------------------------------------------------------------> Time ! Flare/High ! Flare/Med ! There are several different levels used by the DP: SL - Flare-detection sensor level - SXS or HXS count level FS - Flare Status - If SL > NFT, then FS is active GFS - Great Flare Status - If SL > GFT, then GFS is active A.3.3.1 Normal Flare Threshold (NFT) - The flare threshold is defined as absolute number of counts from the SXS or HXS. Current Preset Values: HXS: 256 512 1024 2048 counts/second SXS: 512 1024 2048 4096 counts/second These values can be changed with the RAM patch utility HXS uses HXS-PC1 SXS uses SXS-PC11, -PC12, -PC21, xor PC22 - Pulse Count SOLAR-A DP INDEPENDENT OF SXTE-J Page A-16 Automatic Control Of Observing Mode 16 December 1989 A.3.3.2 Great Flare Threshold (GFT) - The great flare treshold is defined as number of times over normal flare threshold. Current Preset Values: 2 4 8 16 x Normal Flare Threshold These values can be changed with the RAM patch utility A.3.3.3 Flare End Threshold (FET) - The flare end treshold is defined as number of times over normal flare threshold. Current Preset Values: 1/4 1/2 3/4 7/8 x Normal Flare Threshold These values can be changed with the RAM patch utility Cannot specify FET to be greater than 1 in the way the software is implemented. Instability occurs if the intensity is between normal flare thresh and FET. A.3.3.4 Flare Mode Minimum Duration - The DP will not exit the flare mode until a minimum length of time has passed. This time is refered to as the Flare Mode Minimum Duration. Current Preset Values: 5 10 20 40 minutes These values can be changed with the RAM patch utility A.3.4 Leaving Flare Mode - After the minimum flare duration has elapsed, the DP will start checking the flare detection sensor (SXS or HXS) approximately every 1 minute. SOLAR-A DP INDEPENDENT OF SXTE-J Page A-17 Automatic Control Of Observing Mode 16 December 1989 ! Case A ........===========..................... FS is off at first check ! ! ! ! ! ! Case B ........===========----------........... GFS is off at first check but FS is on. ! ! ! ! ! ! ! ! ! GFS is on at first check Case C ........==================---------..... but the flare intensity !Minimum ! has gone down by the 5th !Flare ! check !Duration ! Key: ! indicates when the flare detector is checked ... Quiet mode (high or medium as determined by earlier ground command) === Flare-High mode --- Flare-Med mode In Case B, when the mimumum flare duration had occured, but the flare status is still active, The telemetry rate is changed to medium when all of the following are true: a. The minumum flare duration has been exceeded b. The Flare status is active c. The Great Flare status is inactive This true also during visible orbits (do not want to fill BDR with data with flare protection level since flare cannot overwrite flare) NOTE: If two flares happen in quick succession, and the DP is in Flare/Med, it will stay in medium for the whole observation of the second flare. (physically unlikely though) When a satellite night begins, the Flare mode terminates and Night-Low begins If the radiation belt monitor veto flag is received by the DP within 16 seconds of the Flare flag, the flare flag is ignored and the DP returns to the previous mode. If the DP has been in flare mode for several minutes when the RBM Veto flag is recieved, then the DP will remain in Flare mode. [See section A.3.5 for more information on the radiation belt monitor, and section A.4.5 for BDR protection] BCS-OUT can be separately enabled or disable for either or both of these cases. 1. Flare mode end 2. Enter night mode NOTE: If BCS-OUT at flare end has been enabled, the DP will go into BCS-OUT mode after leaving Flare mode. When the BCS queue has been read out (or times out), the DP will go into Quiet mode. BCS-OUT forces a high bit rate. If the standard BCS telemetry allocation is used to clear out the queue when the DP enters the quiet mode after a flare, the BDR data is saved with Quiet mode protection level when it is actually flare data. SOLAR-A DP INDEPENDENT OF SXTE-J Page A-18 Automatic Control Of Observing Mode 16 December 1989 A.3.5 Avoiding The Radiation Belt - The Radiation Belt Monitor (RBM) consists of two kinds of detectors. These detectors are oriented perpendicular to the sun. Therfore, the RBM is not sensitive to the solar flares but will serve as an alarm for the south atlantic anomaly (SAA). Current Preset Values: SSD-PC 128 256 512 1024 counts/8 seconds SC-PC1 8192 16384 32768 47152 counts/8 seconds Count levels are not checked every 8 seconds. Instantaneous count levels can be determined, so RBM response is very quick. When the radiation belt causes the SXS/HXS to trigger the flare flag, the RBM should tell the DP that it is the radiation belt within a few seconds. The flare mode is changed back to the previous mode (since the DP could already be in the flare mode because of solar flare) The SXS, HXS, HXT, BCS are protected (reduce high voltage) when RBM flag is activated, so only SXT is taking data. The write protection of the data is not written until 8 major frames have passed. Therefore the data taken during the radiation belt will not be written to the BDR with the flare protection. [See section A.4.5 for more detail on the BDR protection algorithm] SOLAR-A DP INDEPENDENT OF SXTE-J Page A-19 Writing Data To The Bubble Data Recorder (BDR) 16 December 1989 A.4 Writing Data To The Bubble Data Recorder (BDR) - Writing to the BDR is normally done sequentially, however, the BDR may be accessed non-sequentially in blocks. This fact allows the DP to skip over certain records in order to avoid overwriting important data with unimportant data. The DP cannot read and write data to the BDR at the same time. The capacity of the BDR is: 83,886,080 bits 10,485,760 bytes 1280 major frames 42.66 minutes of data at the high rate 341.33 minutes (5.7 hours) of data at the medium rate The BDR will have a given protection for every block of data. The length of these block (length of records) is 64 major frames. There are 20 blocks in the BDR which each block being equivalent to ~2 minutes of high rate data. "BDR reproduction" is when there is a ground link and the BDR is read out. The BDR holds approximately 10 Megabytes, if there are 5 downlinks a day, then the following is true Downlinks per day 5 15 ------ ------- MegaBytes per orbit 10 30 MegaBytes per day 50 150 Megabytes per week 350 1.05 Gigabytes per month 1.50 4.50 Gigabytes per year 18.25 54.75 Gigabytes in 3 years 54.75 164.25 A.4.1 Write Protection Level (X) - Each block of BDR data has its own write protection level. X is the write protection level of the data ALREADY in the BDR. X = -1 : no data written to BDR since reading out BDR to the ground 0 : Night mode or Quiet mode data 2 : Normal Flare data (includes preflare data) 3 : Great Flare data (including preflare data) 3 : Campaign Mode (manually set write protection level) Campaign Inverval Command (triggered by OP) sets X=3 for only a select range of time. SOLAR-A DP INDEPENDENT OF SXTE-J Page A-20 Writing Data To The Bubble Data Recorder (BDR) 16 December 1989 A.4.2 Recording Importance Level (Y) - The new data that needs to be saved in the BDR is assigned a recording importance level (Y). The current values are: Y = 1 : Night or Quiet mode record = 2 : Normal Flare record = 3 : Great Flare record = 3 : Campaign Mode Y might be changed to 0 for Night (so night will not overwrite quiet) All values are default and can be updated with RAM patch NOTE: When in BCS-OUT mode, the recording importance level used is the same as the value in the preceding flare record. A.4.3 BDR Block Pointer (P) - This pointer gives the current recording position within the BDR. Just after the BDR is read out, P is set to zero. A.4.4 Basic Algorithm - After the BDR is completely read out, all write protection levels (X) are cleared (set to -1). When some new data is received, the DP will compare the recording importance level (Y) with write protection level (X) of the block that the BDR Block pointer (P) is pointing to. If Y > X(P), the data is written If Y <= X(P), P is incremented (looking for a record that it can write to) Quiet data should overwrite quiet data. Quiet data should over-write night data When there is all great flare data in the BDR, the DP stops the SXT from continuing to command exposures. There is a "BDR busy" flag which signifies if there is space to write current DP mode data. If BDR is unavailable (full) then SXT pauses (NOT SXT control Manual). <> Does the DP search the whole BDR every major frame trying to find a block that does not exist, or is there a parameter that is the current minimum write protection level available in the BDR? <> (0,1,2,4) number of blocks of quiet data preceding a flare will be changed to the flare priority after the flare occurs. The DP does this within <> seconds after the flare flag. SOLAR-A DP INDEPENDENT OF SXTE-J Page A-21 Writing Data To The Bubble Data Recorder (BDR) 16 December 1989 If the flare becomes a great flare, <> of the previous BDR blocks which were saved with the flare priority are changed to great flare priority. The DP does this within <> seconds after the great flare flag. A.4.5 More Detail On BDR Protection - There is a 16 second delay (8 high rate major frames) between the DP mode value and the BDR X value recorded with the data taken at the time. The BDR logic which determines the X value is disabled at a mode transition and remains disabled for 8 major frames. When it is re-enabled, the X value is updated with the value for the CURRENT DP mode. Kosugi Suggestion: Setting the Y value (recording importance level) right away but wait 16 seconds to change X value (write protection level) <> Is it a fixed time (16 sec) or fixed # MFrames (8) <> Temporary X value recorded for every Major frame? The final X value is set AFTER the BDR block is filled. The highest X value in the block is used. ! 1 ! 2 ! 3 ! 4 ! 5 ! 6 ! 7 ! 8 ! 9 ! 10! 11! 12! 13! 14! 15! 16! !---!---!---!---!---!---!---!---!---!---!---!---!---!---!---!---! (Each character is 2 seconds) False Flare (SAA) DP Mode: QQQQQQQQQQQFFQQQQQQQQQ ^ Mode transition due to radiation belt ^ RBM returns the DP to Quiet mode BDR X Value: ________QQQQQQQQQQQQQQQQQQQQQQ ^ Current DP mode is checked and the recording level (X) is changed accordingly True Flare Data: DP Mode: QQQQQQQQQFFFFFFFFFFFFFFFFFFQQQQQQQQQ ^ Mode transition due to true flare BDR X Value: ________QQQQQQQQQFFFFFFFFFFFFFFFFFFQQQQQQQQQ ^ Current DP mode is checked and the recording level (X) is changed accordingly ^^^^^^^^ data is really flare data but will be recorded as quiet data <> What about changing pre-flare protection levels. Is it dependent SOLAR-A DP INDEPENDENT OF SXTE-J Page A-22 Writing Data To The Bubble Data Recorder (BDR) 16 December 1989 on where the BDR block boundaries occur? <> What happens for flares with durations less than 16 seconds? SOLAR-A DP INDEPENDENT OF SXTE-J Page A-23 Writing Data To The Bubble Data Recorder (BDR) 16 December 1989 A.4.6 Example Of Writing To The BDR - The following is an example of how the data is written to the BDR. The unit "!--!" is in bytes (not time). !--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!-- !Quiet-1 ! !Flare-1 ! !Quiet-2 ! !Flare-2 ! !Quiet-3 ! !Great F-1 ! !Flare-3 ! !--!--!--!--!--!--!--!--! << Full capacity of BDR >QQQQQQQQ - all of Quiet-1 is written (nothing in BDR) >FFFFFFFF - all of Flare-1 is written (nothing in BDR) QQQ >QQQQQQ - all of Quiet-2 is written (1) >FFFFF FFF - all of Flare-2 is written (2) QQQ >QQQ - only 2/3 of Quiet-3 is written >GGGGGGGGG - All of Great Flare-1 is written (3) FFF >FFF - 2/3 of Flare-3 is written FFFGGGGGGGGGGFFFFFFFFFFFF - Final BDR Q = Quiet mode data F = Flare mode data G = Great Flare mode data > = Start of the data that is written NOTES: (1) Quiet-2 overwrites part of Quiet-1 (2) Flare-2 data is not contiguous in the BDR memory since it has to skip over the Flare-1 data (3) The Flare-2 data is overwritten even though there is some quiet data in a different block. NOTE: As soon as the BDR is filled with Flare or Great Flare data, no quiet data AND NO Flare data is saved. In fact, pre-great Flare data (flare data) is not saved! <> If there is only one block with quiet protection level, with the DP continually write and over-write to that block? SOLAR-A DP INDEPENDENT OF SXTE-J Page A-24 Writing Data To The Bubble Data Recorder (BDR) 16 December 1989 A.4.6.1 Example/Question 1 Of Writing To The BDR - Assume you have the following observation: FFFFGGGGGG which is a great flare, but the early data must be recorded as flare data. !--!--!--!--!--!--!--!--! << Full capacity of BDR FFFQQQQQFFFFFFFQQQQQQQQQQ - state of the BDR when data starts arriving ^ - BDR Record pointer when data starts arriving FFFFGGGGGG - Continue to write if Y > X(P) The DP does not know that there are other records available that only have quiet data. A.4.6.2 Example/Question 2 Of Writing To The BDR - Assume you have the following observation: FFFFFGGGGGG ^^ at this point, the ealier Fs need to be changed to Gs which is a great flare, but the early data must be recorded as flare data. !--!--!--!--!--!--!--!--! << Full capacity of BDR FFFQQFFFFFFFFFFGGGGGFFFFF - state of the BDR when data starts arriving ^ - BDR Record pointer when data starts arriving FFGGGGGG NOTE: The last three "F"s are not saved because flare will not overwrite flare. There is a gap in the time sequence of the data. !--!--!--!--!--!--!--!--! << Full capacity of BDR FFFFFFFFFFFFFFFGGGGGFFFFF - state of the BDR when data starts arriving ^ - BDR Record pointer when data starts arriving GGGGGG - No pre-great flare data is saved. A.4.6.3 Example/Question 3 Of Writing To The BDR - Assume you have the following observation: GGGGGG Which could occur during a transition from night to day (?) NOTE: Normally, data with a flare status is written before great flare data must be written. !--!--!--!--!--!--!--!--! << Full capacity of BDR FFFQQQQQFFFFFFFQQQQQQQQQQ - state of the BDR when data starts arriving ^ - BDR Record pointer when data starts arriving SOLAR-A DP INDEPENDENT OF SXTE-J Page A-25 Writing Data To The Bubble Data Recorder (BDR) 16 December 1989 GGGGGG - start where ever the pointer is located Pointer should be within the QQ region since it was in night, and night can overwrite quiet. A.4.6.4 Example/Question 4 Of Writing To The BDR - Assume you have the following observation: QQFFFFF which occurs for a flare. The preflare data has to be written to the BDR with Quiet mode level protection, and then the preflare data is changed and marked as Flare data. !--!--!--!--!--!--!--!--! << Full capacity of BDR FFFQQQFFFFFFFGGGGGFFFFFFF - state of the BDR when data starts arriving ^ - BDR Record pointer when data starts arriving #1: QQF - start where ever the pointer is located FFF Flare data will overwrite its own preflare quiet data? #2: ffF - the preflare data is written as quiet data and then changed to flare data right when the flare flag goes active. The actual flare data is not saved (Flare will not overwrite Flare) f = Quiet mode data that is pre-flare data, which is change to flare mode data Answer <> (probably #2) SOLAR-A DP INDEPENDENT OF SXTE-J Page A-26 Reading Data From The Bubble Data Recorder (BDR) 16 December 1989 A.5 Reading Data From The Bubble Data Recorder (BDR) - At the end of a BDR readout, there are several option 1. erase automatically 2. erase after ground command 3. maintain current levels but allow writes 4. disable all writes SOLAR-A DP INDEPENDENT OF SXTE-J Page A-27 DP Hardware 16 December 1989 A.6 DP Hardware - SFE clock increments every 64 seconds SFC clock increments every 16 seconds FF clock increments every 2 seconds <> Regardless of telemetry rate? SOLAR-A DP INDEPENDENT OF SXTE-J Page A-28 DP Software 16 December 1989 A.7 DP Software - A.7.1 Identification Code (IC) - An Identification Code (IC) is a 6 bit word that specifies a sub-system. The ICs are included in the command signal to specify the sub-system to receive the command. X-Y matrix is sub-system specific except for IC = 01 (which has an X-Y matrix that can command one of several spacecraft sub-systems) A.7.2 BC/DC Commands - Discrete Commands (DCs) are commands that typically take only one action to complete (switch on/off for example). DCs are sent with an IC "attached". A single Block Command (BC) is a train of 8 bits. BCs are used to set detailed conditions for the sub-system or to modify the contents of program memory. BCs are also sent with an IC "attached". A.7.3 Organized Commands (OG) - A single organized command is a set of up to 32 elements (OGE = Organized Command Element). Each of these elements contain an identification code and a BC or a DC. There are 128 OGs available which means 4096 elements in total. OG-0 is reseved as UVC-control command (UVC = Under Voltage Condition). The OGs are contained in the TCU. MDM Translation: A single organized command is essentially a subroutine. The length of the subroutine is limited to 32 instructions (BCs/DCs). There are 128 subroutines available in the TCU. Each OGE is 14 bits long. 6 bits for the identification code 8 bits for the BC or DC When an OG is executed, the set of up to 32 elements is sent to the appropriate sub-system. Each BC/DC is separated by 0.25 seconds. The execution of the individual BCs and DCs is identical to as if they were received as a real time command. The contents of the OG memory can be re-written using BCs sent from KSC. SOLAR-A DP INDEPENDENT OF SXTE-J Page A-29 DP Software 16 December 1989 An OG has priority to be executed when an OG and real time command are received at the same time. When a real time command is ignored it will be reflected in the telemetry. A.7.4 Real Time Organized Commands (ROG) - An OG can be started manually in real time from the ground. The OG address to execute must be specified, and then the command to start the OG is sent. A.7.5 Interupt Organized Commands (IOG) - When certain events occur, an interupt occurs and a predetermined OG is started. If an OP is executing, it is interupted. The maximum length of time that an IOG can be delayed is 16 seconds (when an OP sequence and IOG are received simultaneously) Interupts occur for the following. The OG address is also listed. UVC OG-1 Day OG-2 Night OG-3 Flare OG-4 Safe Hold OG-5 (attitude control safe hold) OG-0 is used for a NOP An OG can start an OP which can start a different OG, but an OG cannot call another OG directly. They can start a chain of OGs. ONLY IF OP IS not used for something else (ie for DSN downlinks) Only one OP can run at at time. IMPORTANT^^ ?? Priorities among IOGs is <>. IOGs are triggered in the following manner: UVC : BAT ---> PCU ---> TCU (PCU senses under voltage) Day : NSAS ---> TCU (Sun sensor) Night : NSAS ---> TCU (sun sensor) Flare : SXS/HXS ---> DP ---> TCU (Flare sensor) Safe Hold : ACE ---> TCU (attitude control electronics) SOLAR-A DP INDEPENDENT OF SXTE-J Page A-30 DP Software 16 December 1989 A.7.6 Operation Program (OP) - Operation programs specify when organized commands will be executed (the time sequence of execution). The OP memory has 128 addresses containing control elements (CE). MDM Translation: An OP is essentially a list of subroutine calls that are to be run at predetermined times. A total of 128 subroutine calls can be made at different times (the same subroutine can be called several times). Each CE contains the address of an OG to be executed and the time interval to wait before executing the next CE. Each CE is 16 bits long. 1 bit to either (1) execute the OG or (2) jump to the next OP address (NOP) 7 bits for the address of the OG 8 bits for the time to wait before executing the next CE If a NOP is used, the delay still occurs. The time interval is measured in units of 32 seconds. The following are the delays between commands for different values of the 8 bits: 8-bit value Delay in seconds Delay in minutes ----------- ---------------- ---------------- 0 0 0.00 1 32 0.53 2 64 1.06 8 256 4.27 64 2048 34.13 128 4096 68.27 255 8160 136.00 A.7.6.1 Starting Execution Of An OP - Execution of the OP can be stared by an OP-START command (a DC) sent from KSC. At this time, the CE in address 0 is activated. An OP can be restarted by issuing the OP-CONTINUE command. The OP starts again from the subsequent CE. The execution of the OP can be set to start at an address other than 0 by using the EX-OP-ADDRS SET command (with a BC) to specify the address, and then the OP-CONTINUE command. There is no orbit counter (number of night/day transitions). The OP can only be triggered by a relative time value (cannot specify an absolute time). We can specify that an OG be started "n" seconds AFTER the START of an SOLAR-A DP INDEPENDENT OF SXTE-J Page A-31 DP Software 16 December 1989 event (flare --> quiet mode transition, ...) The night or quiet mode to flare transition and the night to day transition uses OGs, NOT OPs. A.7.6.2 Stopping Execution Of An OP - Execution of the OP is stopped when one of the following occurs: a. Transmission of OP-STOP command (a DC) from KSC b. OP-STOP command occurs in the OP (in one of the OGs) c. UVC-control d. Execution of the CE in OP address 127 (the last CE is completed) A.7.6.3 Examples Of Using Operation Programs (OP) - APPENDIX B HOW TO USE AEC The following sections describe how to use the Automatic Exposure Control (AEC) HOW TO USE AEC Page B-2 Introduction 16 December 1989 B.1 Introduction - B.1.1 Two opposite cases: Bright compact flare < 10 pixels Big even active region > 3000 pixels B.2 Problem Areas - Bleed lines corrupting - follow bleed lines instead of active region on overexposed images. (also, fixed pointing with bright active region right above/below region of interest, AEC will not stabilize if bleed invades FOV) cannot pack the sequence table full. will not respond very quickly. #loops large ==> slower response for other entries. Not a prob for quiet sun (changes slowly) FLARES? ------------------------------------------------------------------------------ Design Note # ?? Solar-A/SXT Analysis on How to Use the Automatic Exposure Control (AEC) Mons Morrison 12-Sept-89 The purpose of this document is to bring to light different factors that must be considered when using the Automatic Exposure Control (AEC). There are several parameters that can be adjusted and this document explores how to set these parameters. In order to understand how to set the AEC parameters, we must first understand the basic elements of how AEC works. The following are the steps that AEC takes: 1. Take an exposure 2. Count pixels: While reading the image out into the BDR, count the number of pixels above an upper threshold, and the number of pixels HOW TO USE AEC Page B-3 Problem Areas 16 December 1989 below a lower threshold. The upper level threshold is refered to as ULT and the lower level threshold is refered to as LLT. 3. Check for Over exposure: This is done by comparing the number of pixels over the ULT to a preset value stored in the sequence table. This stored value is refered to as upper area threshold (UAT). If the number of pixels over the ULT exceeds the UAT, then the image is overexposed and the level should be decreased. 4. Check for Under exposure: This step is only performed if the image is not over exposed. This is done by comparing the number of pixels over the LLT to a preset value stored in the sequence table. This stored value is refered to as lower area threshold (LAT). If the number of pixels over the LLT is less than the LAT, then the image is under-exposed and the level should be increased. NOTE: There is another aspect to AEC which allows the filters to be changed if an extreme exposure is reached and the image is still under or over exposed. This option will not be discussed here. For a full description of the option, please see the LPARL SXTE-J Software Document. Parameters that must be adjusted for EACH image: (they are a function of summation mode) ULT - (Units: DN) LLT UAT - (Units: # pixels) LAT Filter Alternation Enabled Parameters that are set for all images Exposure Step Size AECL AECH0 AECH1 Disable 10% Mask Use Areas of Sensitivity or Instability: ------------------------------------ 1. Instability due to ULT and LLT being too close together (modified exposure level step size because of this) Use example where LAT = UAT 2. Response time: Each exposure entry by itself (many entries ==> slower response) 3. Instability when less than 3 exposure entries. 4. Sensitivity to UAT for small compact flares (==> need to set UAT to be small) Small UAT ==> sensitive to dark spikes Conclusions on how to set up parameters: ---------------------------------------- 4. Dynamic range (want to set LLT as high as possible) ULT = 90% of full well HOW TO USE AEC Page B-4 Problem Areas 16 December 1989 For more detail on AEC please see the M.Morrison SXTE-J Software Document ------------------------------------------------------------------------------ ULT and LLT too close ?? Show plots of instability - Note that it can actually accidentally stabilize APPENDIX C FUNDAMENTAL CAMERA OPERATION & CAPABILITIES The following sections describe the operation of the camera. FUNDAMENTAL CAMERA OPERATION & CAPABILITIES Page C-2 Commanding 16 December 1989 C.1 Commanding - ROIs Guard band fast line transfer full frame flushes long words C.2 Baseline Stabilization (BLS) Pixels - purpose Corruption of data C.3 Light Transfers -