Range-Doppler algorithm for processing bistatic SAR data based on the LBF in the constant-offset constellation

This paper focuses on processing bistatic synthetic aperture radar data in the constant-offset configuration using the range-Doppler algorithm. The analytical two-dimensional signal spectrum introduced by Loffeld (Loffeld's Bistatic Formula: LBF) is used as the bistatic point-target reference spectrum. This spectrum consists of two key phase terms: a quasi-monostatic (QM) term similar to the monostatic phase of a point target, and a bistatic deformation (BD) term which is an intrinsic feature of the bistatic geometry and is due to the separation between the transmitter and receiver platforms. In this paper, both phase terms are combined into a single phase so that by directly using a Taylor series expansion, we may derive the key components of the signal including the azimuth modulation, range cell migration (RCM), and range-azimuth coupling. These terms can then be dealt with using the conventional processing techniques. In this paper, the range-Doppler algorithm is used which utilizes interpolation to remove the RCM, as in the monostatic case. Finally, simulation results are provided to verify the formulations.