A new Bi-SAR T/R relative speed estimation method using nadir echo

In this paper, a new bistatic SAR T/R relative speed estimation method using nadir echo is present. This method first exact the nadir echo from the range compressed SAR data, then the time-frequency estimation method is adopted to obtain the instantaneous frequency of the nadir echo, which is proportional to the relative speed of the T/R platform, finally, the relative speed is estimated by searching the maximum values of the STFT spectrogram at different time. Compare to the traditional motion parameter estimation method, this method can obtain the instantaneous relative speed between the T/R platforms rather than an average speed between them, and improve the quality of bistatic SAR image finally.