Point Spread Function Analysis for BSAR With GNSS Transmitters and Long Dwell Times: Theory and Experimental Confirmation

This letter conducts a point spread function (PSF) analysis for bistatic synthetic aperture radar (BSAR) systems where the transmitter is in medium Earth orbit, and the receiver is fixed on the ground. To achieve a reasonable azimuth resolution under such a configuration, the trajectory of the satellite can no longer be approximated as a straight line; therefore, current methods for PSF analysis are insufficient. The solution proposed involves extension of the generalized ambiguity function to accommodate satellite trajectory curvature. The theoretical analysis shows effects unlike those observed in monostatic or even the general BSAR and is verified by both simulation and experimental results using navigation satellites as the transmitting platforms.