An improved algorithm for passive bistatic radar detection and parameters estimation

In passive bistatic radar system, both detection and joint estimation of time delay and Doppler shift of target are based on the cross-ambiguity function (CAF) between direct-path signals and target echoes. However, the drawback of this approach is the excessive processing load which is caused by the fast Fourier transforms (FFT) for long input samples. Since the interested frequencies of target often occupy a small portion of the whole frequency range, it only required to analyze the sub-band of the whole frequency. A decimation technique which can decrease the operation complexity was applied to solve this issue. The cascaded integrator-comb filter (CIC filter) theory was briefly introduced, followed by detailed signal processing procedures used to implement the target detection and parameters estimation. This improved algorithm needs several extra steps to decimate the signals, while greatly reduces the overall computation complexity with almost no loss of signal processing gain. Finally, the effectiveness of this proposed algorithm is verified by the real data analysis.