Frequency domain imaging algorithm for spaceborne/airborne hybrid bistatic SAR

A frequency domain imaging algorithm for the hybrid spaceborne/airborne BSAR is presented. The key point of deriving the algorithm is the analytical evaluation of the system point target response's 2-D spectrum. To overcome the difficulty of resolving analytical solution for the stationary phase point, the spectrum's phase is approximated by two-order Taylor expanding around the point, which is not only in the neighborhood of the system's corresponding stationary phase point but also can be obtained analytically. Thus the approximated analytical spectrum is pretty close to the actual one. In the imaging algorithm, both range-dependent range cell migration and azimuth-dependent range cell migration are compensated in two steps: Inverse Scaled Fourier Transform which can be realized through the chirp z-transform and phase multiplication. The validity of the algorithm is demonstrated by experiment with the simulated data.