Gamma ISP: Reference Manual

Baseline Parameter File

(ASCII file) such as <orbit1_orbit2>.base

NAME
<orbit1_orbit2>.base - contains an information on the interferometric baseline as used by the Interferometric SAR Processor ISP.

SYNOPSIS
not executable. May be created using base_orbit or base_est_fft.

EXAMPLE
12957_13086.base, an existing baseline parameter file for the SAR on ERS-1 is shown as example:

initial_baseline(TCN):	0.00000 -123.03783 47.40700 m m m
initial_baseline_rate:	0.00000 0.09185 0.23839 m/s m/s m/s
precision_baseline(TCN):	0.00000 0.00000 0.00000 m m m
precision_baseline_rate:	0.00000 0.00000 0.00000 m/s m/s m/s
unwrap_phase_constant:	0.0000 radians

This Example represents the state as it occurs after the co-registration, interferogram generation and removal of the phase trend, but before the derivation of the terrain heights. Therefore some values at the end of the file are not yet determined (set to zero).

FORMATS AND DEFINITIONS
The formats are defined in the ISP type definition file typedef_ISP.h

initial_baseline(TCN):	Initial estimate of interferometric baseline at center of SLC-1 (in TCN coordinates, in m) derived from orbit state vectors or the interferogram fringe rate.
initial_baseline_rate:	Rate of initial estimate of interferometric baseline at center of SLC-1 (m/s).
precision_baseline(TCN):	Precision estimate of interferometric baseline at center of SLC-1 (in TCN coordinates, in m) derived using least squares fit to ground control points.
precision_baseline_rate:	Rate of precision estimate of interferometric baseline at center of SLC-1 (m/s).
unwrap_phase_constant:	Interferometric phase constant estimated using Least Squares model fitting of the baseline from ground control points (radians)

DESCRIPTION
<orbit1_orbit2>.base - contains information on the interferometric baseline. An initial estimate of the interferometric baseline is derived either from the orbit state vectors listed in the SLC parameter file using the ISP program base_orbit or from the interferogram fringe rate using base_est_fft. Later on a precision estimate is obtained using the unwrapped interferometric phase and a number of ground control points.

The interferometric baseline is used for the removal of the flat Earth phase trend and for the derivation of the interferometric height estimate<orbit1_orbit2>.off

OPTIONS
None.