Frequency Agile Waveform Design and Coherent Processing for High-speed Target Detection

Frequency agile waveform has excellent interception and interference immunity for radar. However, the agile frequency introduces jitter initial phase and agile Doppler, which results in a non-coherent echo signal, making it difficult for the target to obtain a high signal-to-noise ratio (SNR) gain. In addition, the range cell migration (RCM) correction is also a problem in frequency agile radar for high-speed target detection. In this article, a frequency agile waveform with the same frequency set in each group and a novel processing method is proposed for high-speed target detection. The first pulse with same carrier frequency in each group can be used to estimate the coarse velocity via the keystone (KT) algorithm. Thus, the RCM correction in a coherent processing interval (CPI) can be realized with the estimated velocity. Then, the agile initial phases can be mutually canceled by the same-frequency signals. Finally, the coherent accumulation after cancellation can be realized by the non-uniform discrete Fourier transform (NDFT). Simulation experiments verify the effectiveness of the proposed waveform and processing method for high-speed target detection.