Bistatic SAR - Some Reflections on Rocca's Smile ..

摘要

The paper derives a vectorial model for expressing transmitter and receiver trajectories for arbitrary transmitter and receiver motion in a bistatic SAR constellation. The point target response is first modeled in the space/time domain then transformed into the frequency domain by the method of stationary phase giving the point target reference spectrum. In the reference spectrum two phasor functions can be identified, the first one resembling some quasi monostatic contribution and the second one being a bistatic deformation phasor transforming into an elliptic arc in the spatial domain known. The multiplication of the two phasors in the frequency domain transforms into a convolution in the space/time domain; indicating that the bistatic range history can be expressed as a convolution of some monostatic hyperbola with a bistatic deformation term, consisting of an elliptic arc segment. In general the bistatic deformation term is azimuth time and range varying, while in the case of identical velocity vectors it is constant with respect to azimuth time. The paper shows that the solution which has been found in the geophysical community for the special case of two sensors moving at identical velocity vectors (constant offset case being related to 'Rocca's smile') is in fact a specialization obtained from the more general approach considered here.