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ASF/STEP's Interferometry Software
Introduction
One of the software projects we have been working on at STEP is
interferometry. For those new to this term, interferometry is the study of
interference patterns caused by either two signals received at the same
source or one signal being received at two sources.
How do we get interference patterns from one signal receiving at one
satellite?
Most Earth-observing satellites orbit in a repeat pattern.
This means that it will fly over approximately the same patch of ground
once every orbital period. However, the satellite does not fly EXACTLY over
the same spot. With this separation, we have one signal being received
at two sources. Hence, an interference pattern can be generated.
For SAR satellites, this interference pattern contains information
about a difference in path length. Depending on the situation, this
interferogram can contain information about:
- Topography, to sub-10m RMS accuracy.
- Surface motion or deformation, to sub-centimeter accuracy.
- Surface change, at the centimeter level.
Software
The interferometry software is available to
registered users and requires a password.
If you are registered, use the quick link below to download the source code.
Software Tutorial
A step-by-step description
of each ASF-STEP interferometry tool is below.
This set of web pages describes the 8/27/98 release.
- Register_ccsd turns SAR signal data into an interferogram.
- Register_sic turns single-look-complex data into an
interferogram.
- Tandem_ifm turns an interferogram into an accurate DEM.
We also have a list of concepts
used in interferometry, and a set of web pages organized
by program.
If you would like test data, contact Rick Guritz for more
information.
Examples
Articles, Papers, and Other Sources of Information
When taken in the context of the history of science, interferometry using earth remote sensing
satellites is brand new. However, there is plenty of information available that discusses
interferometry, especially interferometry using ERS-1 SAR data. Check out our bibliography for more information.
Acknowledgements
The staff of STEP would like to thank the following people who either helped
with advice or contributed software or both.
- Rob Fatland
- Harold Garbiel
- Shusun Li
- C. K. Shum
- Howard Zebker