Coherent signal processing method for frequency-agile radar

The frequency-agile radar especially that adopts the pulse-to-pulse random frequency agility is the important anti-electronic countermeasure measure. However, nowadays when the frequency-agile radar operates in the state of pulse-to-pulse random frequency agility, only the incoherent signal processing are used as the coherence of echo phase has been destroyed. This paper mainly focused on coherent signal processing method for frequency-agile radar. The characteristic of pulse-to-pulse frequency-agile radar echo of moving target is discussed in detail. Entropy of Doppler profile is introduced as the indicator to measure the degree of mismatch of echo phase induced by frequency agility. A coherent signal processing method based on minimum entropy is proposed to correct mismatched phase of frequency-agile radar. With loop searching for range and velocity of targets a compensation factor which has minimum entropy is chosen as best candidate. Finally, simulation results of coherent signal processing for frequency-agile radar are presented to verify that after the phase compensation based on minimum entropy method, the echo of pulse-to-pulse frequency-agile radar can be successfully coherent integrated.