Gamma MSP: Reference Manual

PALSAR_antpat

NAME
PALSAR_proc - Extract specified antenna pattern from a PALSAR JAXA supplied data file and writes into an MSP format antenna file

SYNOPSIS
PALSAR_antpat <SAR_par> <PROC_par> <PAL_ANT> <ant_file> [Beam_ID] [TX_POL] [RX_POL]

<SAR_par>	(output) MSP SAR Sensor Parameter File
<PROC_par>	(output) MSP Processing parameter File
<PALSAR_ANT>	(input) PALSAR antenna pattern data file provided by JAXA (e.g. palsar_ant_20061024.dat)
<ant_file>	(output) MSP format antenna pattern file (text format)
[Beam_ID]	input) PALSAR mode beam ID, if not provided the program will determine the appropriate beam from the SAR_par look angle parameter.
[TX_POL]	(input) extracted channel transmit polarization 0: H (default) 1: V
[RX_POL]	(input) extracted channel receive polarization 0: H (default) 1: V

Beam IDs for different center-beam look angles and PALSAR modes: Beam ID look angle (deg.) Mode ======================================= 0 9.9 FBS 1 14.1 FBS 2 17.9 FBS 3 21.2 FBS 4 25.8 FBS 5 28.7 FBS 6 30.8 FBS 7 34.0 FBS 8 36.7 FBS 9 38.5 FBS 10 41.3 FBS 11 43.4 FBS 12 45.1 FBS 13 46.6 FBS 14 47.7 FBS 15 49.0 FBS 16 50.0 FBS 17 50.6 FBS 18 19.9 WB1, WB2 Beam 1 19 25.8 WB1, WB2 Beam 2 20 30.3 WB1, WB2 Beam 3 21 33.6 WB1, WB2 Beam 4 22 36.0 WB1, WB2 Beam 5

EXAMPLES:PALSAR_antpat 20060820_HH.sar_par p20060820_HH.slc.par palsar_ant_20061024.dat 20060820_HH._antenna.gain 7

Select beam FBS beam 7 from palsar_ant_20061024.dat

PALSAR_antpat 20060820_HH.sar_par p20060820_HH.slc.par palsar_ant_20061024.dat 20060820_HH._antenna.gain -

Determine beam based on the look angle stored in the SLC_par sensor parameter file.

DESCRIPTION

This program parses the the JAXA supplied antenna pattern file and generates an antenna pattern file in Gamma format. Differerent antenna patterns are supplied for each of the PALSAR modes. A copy of the JAXA antanna pattern file is in the $MSP_HOME/sensors directory under the name palsar_ant_20061024.dat and is the file used by JAXA for their processing. palsar_ant_20061024.dat, palsar_ant.dat_f_a, and palsar_ant.dat_f_b are in text format and can be examined using a text editor. The latest updates of the antenna pattern data are in files

palsar_ant.dat_f_a PALSAR antenna pattern to be used for acquisitions on or after 7 August 2006
palsar_ant.dat_f_b PALSAR antenna pattern to be used for acquisitions before 7 August 2006

The start of each pattern in the file has the following parameters:

NN:                 number of the pattern samples in the current beam
OFF_NADIR0:         off nadir angle at the first line of the data file (deg.)
DTH:                off nadir anguler increment (deg.)
Ghh, Ghv, Gvh, Gvv: antenna peak gain for four polarizations (dB)

Then the individual measurements of the antenna pattern consist of 6 values for each angle:

ONA, Beam_Angle, ghh, ghv, gvh, gvv

where ONA is the off nadir angle, Beam_Angle is the angle relative to the physical boresight of the pannel, and ghh, ghv, gvh, gvv are the relative antenna pattern gains in dB normalized by the peak values.

If the Beam_ID and polariazation are omitted from the command line, they are determined from the SAR_par and PROC_par parameter files. Normally these values would not be supplied because you want to extract the antenna pattern that pertains to the current data set. The gain values are then converted to 1-way power rather than dB and written out in the MSP format for antenna patterns.

The MSP text format antenna pattern consists of pairs of values, one pair/line. The first is the angular offset relative to antenna boresight angle, and the second number is the 1-way antenna gain (amplitude). The look-angle at the center of the beam is specified in the SAR sensor parameter file.

Note that beams 18 to 22 are are used for Wide-Beam (WB) ScanSAR data.

SEE ALSO
Users Guide, PALSAR_proc