;+
; NAME:
;     GET_TPCAL_STRUCT
; PURPOSE:
;     Define structure necessary for holding total power calibration information
;     from the TPCAL segment.
; CATEGORY:
;     OVRO APC DATA ANALYSIS
; CALLING SEQUENCE:
;     tpcal = get_tpcal_struct()
; INPUTS:
; OPTIONAL (KEYWORD) INPUT PARAMETERS:
; ROUTINES CALLED:
; OUTPUTS:
;     tpcal    an empty total power calibration structure
; COMMENTS:
; SIDE EFFECTS:
; RESTRICTIONS:
; MODIFICATION HISTORY:
;     Written 27-Jul-1999 by Dale E. Gary
;     20-Nov-1999  DG
;       Slight change to return 1.0 for TPFAC as a default rather than zero.
;     27-Aug-2005  DG
;       Added a third index to TPFAC and TPRMS to account for both R and L
;       data--a result of all dishes having R and L.
;-
function get_tpcal_struct

   ; Define trajectory structure
   tpcal = {tpcal, tls27m: get_tl_struct(),$  ; The TIME/LABEL structure for 27m TPCAL
                   tls02m: get_tl_struct(),$  ; The TIME/LABEL structure for  2m TPCAL
                   tpfac:    fltarr(10,86,2)+1.0,$  ; Factors for 10 feeds at 86 frequencies
                   tprms:    fltarr(10,86,2)}   ; The errors in the factors.

return,tpcal
end