Abstract: Long-term coherent integration is a main method to improve gain in target identification for passive radar. However, tangential-speed leads to Doppler expansion based on bistatic model which decreases the gain and then degrades the detection range. In this work we discuss the contribution factor of Doppler migration and propose an algorithm to deal with Doppler migration based on sub-band double carrier frequency conjugated processing (SDCFCP). SDCFCP increases the equivalent wavelength of composite signal, makes Doppler quadratic term close to zero, and solves the Doppler migration problem. We also propose an improved method to decrease PRF at azimuth and enhance the weak target detection ability. SDCFCP can be applied conveniently with little calculation work. Moreover, the algorithm is useful on multi-target scenario. Finally, experiments based on simulated and real signals verify the proposed algorithm.

Key words: passive radar, coherent integration, Doppler migration, SDCFCP