A Coherent Accumulation Resolving Range Ambiguity Algorithm Based on Chirp Rate Polarity Modulation with M-Sequence

Range ambiguity has always been an inherent problem in pulse instrumentation radar system. At present, the traditional resolving range ambiguity algorithm is generally based on the Remainder Theorem. However, when radar detects medium or high orbit space target, the signal-to-noise ratio of the radar echo is low because the space target is far away and its radar cross section is small. In this case, the efficiency of the traditional resolving range ambiguity algorithm is reduced and even the algorithm cannot be applied. Therefore, in order to solve the problem of range ambiguity in the condition of low SNR radar echo, a coherent accumulation resolving range ambiguity algorithm based on chirp rate polarity modulation with M-sequence is proposed. In this algorithm, the M-sequence is used to modulate the chirp rate polarity of radar transmitting signal (chirp signal). Then the radar echo signal is compressed by reference matching filtering. Finally, the sliding window coherent accumulation process is applied to resolving the radial range ambiguity of space target. The simulation experiment shows that the proposed algorithm can improve the resolving range ambiguity efficiently, which is especially suit for engineering application.