In airborne two-antenna interferometric SAR system, the returned pulse may be reflected by parts of the aircraft platform into the antennas, and this is called multipath effect which will cause oscillating phase errors and hence height errors. This paper presents a theoretical model to compute the multipath error. In this model the multipath phase error is a function of look angle or ideal phase, and the unknown parameters of the model can be estimated from distributed targets with known elevation. On the basis of the model, a method and processing procedure can be used to correct multipath error effectively, and this paper illustrates its successful application to interferometric SAR data collected by Institute of Electronics, Chinese Academy of Sciences.

The accuracy of the digital elevation model (DEM) generated by the interferometric synthetic aperture radar (SAR) partly depends on the accuracy of system parameters, so it is necessary to calibrate the system parameters. The traditional calibration method models the elevation error as a linear function of parameter biases, and solves the biases through the sensitivity equations. This paper presents a weighted calibration method applicable to interferometric SAR data. It introduces the weightings to the sensitivity equations to discriminate the ground control points (GCPs) with different correlation coefficients and locations. This weighted calibration method can improve the DEM accuracy, and this paper illustrates its successful application to airborne interferometric SAR data collected by Institute of Electronics, Chinese Academy of Sciences.

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