Application of the interferometric synthetic aperture radar (IFSAR) correlation file for use in feature extraction

Fine resolution synthetic aperture radar (SAR) and interferometric synthetic aperture radar (IFSAR) have been widely used for the purpose of creating viable terrain maps. A map is only as good as the information it contains. Therefore, it is a major priority of the mapmakers that the data that goes into the process be as complete and accurate as possible. In this paper, we analyze IFSAR correlation/decorrelation data to help in terrain feature information. The correlation data contains the correlation coefficient between the bottom and top IFSAR radar channels. It is a 32-bit floating-point number. This number is a measure of the absolute complex correlation coefficient between the signals that are received in each channel. The range of these numbers is between zero and unity. Unity indicates 100% correlation and zero indicates no correlation. The correlation is a function of several system parameters including signal-to-noise ratio (SNR), local geometry, and scattering mechanism. The two radar channels are physically close together and signals are inherently highly correlated. Significant difference is found beyond the fourth decimal place. We have concentrated our analysis on small features that are easily detectable in the correlation/de-correlation data and not so easily detectable in the elevation or magnitude data.