An efficient coherent integration method for RFPA radar signals in high-speed and multi-target scenarios

Although random frequency and pulse repetition interval (PRI) agile (RFPA) radar signals provide strong electronic counter-countermeasures (ECCM) capabilities, coherent integration under high-speed and multi-target scenarios remains a critical but insufficiently explored challenge. We propose an efficient coherent integration method termed RFPA-KT-NUFFT, which combines Keystone transform (KT) and nonuniform fast Fourier transform (NUFFT). The truncated-sinc-interpolation-based KT exploits low computational complexity to correct range migration and decouple the interdependencies between frequency and PRI. Next, a tailored phase compensation function is developed to harness the frequency-agile bandwidth, thereby enabling high range resolution and facilitating multi-target separation. Finally, NUFFT efficiently handles the nonuniform slow-time sampling for coherent integration. Monte Carlo experiments with a 500-sequence agile waveform library demonstrate that the proposed method significantly reduces runtime while maintaining integration performance comparable to existing optimal methods, offering a viable solution that achieves a favorable trade-off between performance and efficiency in high-speed and multi-target scenarios.