An Approximated Analytical Solution for Two-Dimensional Spectrum of Spaceborne/Airborne Hybrid Bistatic SAR

A solution for the approximated two-dimensional spectrum's analytical expression of spaceborne/airborne hybrid BSAR is presented. To overcome the difficulty of resolving analytical solution for the system's stationary phase point, the two-dimensional 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 spaceborne/airborne hybrid BSAR system response's approximated spectrum is pretty close to the actual one and can be expressed analytically. Taking TerraSAR-X as transmitter and PAMIR as receiver, the phase error caused by the approximation is simulated for different point targets in the image scene, and the simulated echo of point target is focused by the approximated two-dimensional spectrum. The simulation results demonstrate the validity of the proposed solution.