High range resolution (HRR) improvement using synthetic HRR processing and stepped-frequency polyphase coding

Abstract

The authors exploit radar waveform coding techniques to improve high range resolution (HRR) performance. Phase-coded, stepped-frequency (PCSF) waveforms are presented and performance characterised relative to a common 13-element biphase-coded PCSF waveform. Analysis includes PCSF waveforms using biphase coding derived from Gold and minimum peak sidelobe level codes. Synthetic HRR results for PCSF waveforms using Frank and P4 polyphase codes are also presented and achieve HRR performance rivalling their biphase counterparts. Individual code performance is analysed and characterised using a single-point target and realistic target scene comprised of 320 closely spaced complex scattering centres, representing a fighter-sized aircraft. The P4 polyphase coded waveforms achieved best overall HRR performance and were least sensitive to Doppler variation for relative velocities up to 250 m/s. The P4 polyphase coded synthetic HRR profiles exhibit ∼ 7.0 dB and 10.0 dB improvement (peak sidelobe level reduction) relative to Frank and biphase coding, respectively.