In this paper, an imaging processing method for Bistatic Synthetic Aperture Radar (BiSAR) utilizing navigation satellites is investigated. Considering the special problems regarding the use of Global Navigation Satellite System (GNSS) signals to form SAR images, direct signals are used to estimate range migration parameters, and range migration is corrected in the azimuth time domain. The Doppler sensitivity of phase-coded signals was solved by Doppler compensation. By fitting the Doppler phase history with a high-order polynomial, the Doppler phase history is accurately approximated and the azimuth compression is implemented by de-chirp processing. By performing simulations and experimental data processing, the proposed method is verified.