SIR-C Multifrequency Radar Backscatter Database for Terrain

Database Report
Graphical User Interface



On two missions, in the spring and fall of 1994, the Space Shuttle carried a multifrequency synthetic-aperture radar (SAR) to image large segments of planet Earth. The SAR instrument package is known as the Shuttle Imaging Radar-C, or SIR-C for short. The letter "C" refers to the fact that this particular instrument configuration was the third SAR to fly on the Space Shuttle; SIR-A was flown in 1981 and SIR-B in 1984. To date, SIR-C remains the most advanced imaging radar to fly in space. Unlike earlier missions-as well as missions flown since 1994-all of which carried single-frequency SARs, the SIR-C instrument is the only SAR to acquire backscatter data at three different frequencies, and to do so simultaneously. The SIR-C instrument included fully polarimetric SARs that operated at 1.25 GHz (L-band) and 5.3 GHz (C-band) and a non-polarimetric SAR with VV polarization at 9.6 GHz (X-band).

In support of the SIR-C mission, a team of research investigators at the University of Michigan carried out an extensive "ground-truth" survey to characterize the terrain across long swaths of the scenes imaged by the SIR-C radars. The ground-truth surveys included terrain type and associated ancillary data. This document is made available to SAR users and designers interested in quantitative information about the statistical distribution of the radar backscattering coefficient σ0 (dB) for various types of terrain, at any of the three frequency bands operated by SIR-C. The extraction of data from the voluminous database is facilitated by the Graphical User Interface (GUI) described in detail in the sections that follow.