On the use of the gradient to determine bistatic SAR resolution

In evaluating the performance of a bistatic SAR (synthetic aperture radar) system it is important to determine the regions on the ground which satisfy range and cross-range resolution requirements. The vector gradient can be used to derive these resolutions, producing equations which, in addition to providing insight into the problem, can easily be implemented in computer code. Cross-range resolution is defined in terms of Doppler and range resolution, and results from a computer code implementing the equations derived are presented. Specifically, results are given for a 1000-km-altitude circular orbit satellite transmitter and an aircraft receiver (10-km altitude, 200 m/s).<>