Range Migration Correction Method Based on Improved Keystone Transform for GPS-based Passive Radar

Passive Radar based on GPS satellite signal has the advantages of full-time irradiation and wide radiation range. It is an important research direction of Passive Radar. However, the GPS satellite signal is weak, it is necessary to improve the signal-to-noise ratio by coherent accumulation in target detection. However, the coherent accumulation of moving target signals will cause the problem of range migration, resulting in the reduction of accumulation effect. Keystone transform can correct range migration of moving targets in coherent accumulation time, traditional keystone transform has a large amount of computation, if there is Doppler ambiguity, traditional keystone transform will have "Half-Blind-Velocity" effect. The paper proposes a keystone transformation method based on scale transformation. The new method can reduce the amount of calculation and suppress the \Half-Blind-Velocity" effect, so as to enhance the effect of coherent accumulation.