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NAME

cams2det - Calculate offsets and rotations in HXI coordinates using CAMS telemetry input

USAGE

cams2det infile1 infile2 outfile instrume

DESCRIPTION

The cams2det task calculates HXI coordinate system offsets and rotations due to the wobbling of the extended optical bench. The two input files are telemetry FITS files, one from CAMS1 and one from CAMS2. The output is a single FITS file with new columns containing the offsets in HXI RAW coordinates and the sine and cosine of the rotation angle. The output file can be converted into an attitude file by running the task det2att2 on the output file. The cams2det task must be run separately on each of the two HXI units, HXI1 and HXI2.

The task matches the input TIME columns of 'infile1' and 'infile2'. When a match is found, the task uses data from both CAMS units to derive the offsets and rotation angle. If no match is found within a given tolerance (fixed in the software to 1 ms), the offset for that row is calculated based on a single CAMS unit and the rotation angle is set equal to zero.

The following columns are written to the output offset file:

TIME [s]: derived from the TIME column present in the two input CAMS data files.
DELTARAWX/DELTARAWY [pixels]: the component in the HXI RAW X/Y direction of the offset required to correct for the wobble of the HXI extended optical bench.
COSANGLE/SINANGLE: the cosine/sine of the rotation angle required to correct for the wobble of the HXI extended optical bench.
X1/X2: the motion in the X-direction in the local coordinate system of the CAMS1/CAMS2 unit. It is copied directly from the X column in the input file 'infile1/infile2'.
Y1/Y2: motion in the Y-direction in the local coordinate system of the CAMS1/CAMS2 unit. It is copied directly from the Y column in the input file 'infile1/infile2'.
JUMPX1/X2: the difference between successive values of X1/X2.
JUMPY1/Y2: the difference between successive values of Y1/Y2.
QUALITY1/QUALITY2: copied directly from the QUALITY column of 'infile1/infile2'.
XDISTANCE/YDISTANCE [mm]: the X/Y distance between the CAMS units, (X2 - X1)/(Y2 - Y1). This is calculated as an intermediate step in deriving the offset and rotation angle.
DELTASATX/DELTASATY [mm]: the offset equivalent to DELTARAWX/DELTASATY, but measured in the satellite (SAT) coordinate system.
BAD_UNITS: indicates which CAMS unit has valid data. If this equals to 0, both CAMS units have valid data, if it equals to 1, only CAMS2 has valid data, and if it equals 2, only CAMS1 has valid data.
CALC_QUALITY: generated internally to the code and is used to indicate one or more of the following situations.

CALC_QUALITY = 0: successful calculation of offsets and rotation (twist) angle.
CALC_QUALITY = 1: the rotation angle is not calculated because one CAMS unit does not have good data.
CALC_QUALITY = 2: tiny twist angle fixed to cos(twist)=+/-1, sin(twist)=0 due to problem in the calculation of the twist angle.
CALC_QUALITY = 4: no calculation of offsets or twist angle possible.

PARAMETERS

infile1 = cams1_data.fits [filename]: Name of the input CAMS1 telemetry FITS file containing the X and Y positions determined by the CAMS1 system.
infile2 = cams2_data.fits [filename]: Name of the input CAMS2 telemetry FITS file containing the X and Y positions determined by the CAMS2 system.
outfile = cams_det.fits [filename]: Name of the output offsets file containing the offsets and rotation angle in HXI RAW coordinates.
(cams1teldef = CALDB) [filename CALDB|file name]: Name of the CAMS1 teldef file. If the parameter is set to CALDB, the file is read from the calibration database.
(cams2teldef = CALDB) [filename CALDB|file name]: Name of the CAMS2 teldef file. If the parameter is set to CALDB, the file is read from the calibration database.
(hxiteldef = CALDB) [filename CALDB|file name]: Name of the HXI1 or HXI2 teldef file. If the parameter is set to CALDB, the file is read from the calibration database.
instrume [string HXI1|HXI2|1|2]: Name or identifier (1 or 2 for HXI1 or HXI2 respectively), of the HXI unit for which the offsets are to be derived.
(inext = CAMS_DATA) [string]: Name of data extension in 'infile1' and 'infile2'.
(outext = CAMS_OFFSETS) [string]: Name of the extension of the output file to which the offset data is written.
(flipsign = no) [boolean yes|no]: Flip the sign of the output offsets and angles. This parameter is used for debugging by setting 'flipsign=yes'.
(startsys = RAW) [string RAW|FOC]: Starting coordinate system.
(buffer = -1) [integer -1|0|N]: Rows to buffer (-1=auto, 0=none, N>0=numrows).
(clobber = no) [boolean yes|no]: Overwrites the existing output file if set to yes.
(chatter = 1) [integer 0|1|23]: Chatter level for output. Set to 0 to suppress output, or to 1, 2, or 3 for increasing the chatter of the output.
(logfile = !DEFAULT) [string DEFAULT|NONE|file name]: Log file name. If set to DEFAULT, uses the name of the task and, if preceded by "!", overwrites the file if it exists. If set to NONE, no log file is created.
(debug = no) [boolean yes|no]: Diagnostic output is printed to the screen if set to yes.
(history = yes) [boolean yes|no]: Records tool parameters in HISTORY.

EXAMPLES

Calculate the offsets from the CAMS unit for motions of the HXI1 instrument. The teldef files for the CAMS are found using a CalDB query. The teldef file for the HXI is specified on the command line.

   cams2det infile1=CAMS1.fits infile2=CAMS2.fits outfile=HXI1_offsets.fits cams1teldef=CALDB cams2teldef=CALDB \
      hxiteldef=hxi1_teldef.fits instrume="HXI1 clobber=yes

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