Gamma DIFF/GEO: Reference Manual

base_add

ANSI-C program: base_add.c

NAME
base_add - Add/subtract baseline components of 2 baseline files.

SYNOPSIS
base_add <base_1> <base_2> <base_out> [mode]

<base_1>	1. input baseline file
<base_2>	2. input baseline file
<base_out>	ouput baseline file
mode	add/subtract mode (default=1: add, -1: subtract (base_1-base_2))

EXAMPLE
base_add 20040622_20040621.base_orb 20040622_20040621.base_fft 20040622_20040621.base

Adds the two baselines (each component).

base_add 20040622_20040621.base_orb 20040622_20040621.base_fft 20040622_20040621.base -1

Subtracts second baseline from first baseline.

DESCRIPTION
base_add reads two baseline files and generates a new baseline file by addition or subtraction of the components of the the two baseline files.

An initial estimate of the baseline using orbit state vectors (obtained with the program base_orbit of the Gamma Interferometric SAR Processor, ISP ) may not be sufficiently accurate. The remaining fringes in the differential interferogram may be estimated usingFourier analysis and removed in a second step (using the program base_est_fft of the Gamma Interferometric SAR Processor, ISP). The two baseline files obtained (one from the orbits and one from the Fourier analysis of the differential interferogram) may then be added using base_add to obtain a single baseline estimate.

Applying these ideas to data over level terrain permits precisely estimating the interferometric baseline. By addition and subtraction of baselines the baselines of other SLC pairs can be estimated. This is of interest, as larger baselines or baselines for longer time intervals may be difficult to estimate from the data itself due to low coherence. The described procedure may be applied iteratively to improve the result.

SEE ALSO
typedef_ISP.h.