Multicarrier radar signal - pulse train and CW

A multicarrier complementary phase-coded (MCPC) radar signal employs N subcarriers simultaneously. The subcarriers are phase modulated by N different sequences that constitute a complementary set. The subcarriers are frequency-separated by the inverse of the duration of a phase element t/sub b/. An N/spl times/M MCPC pulse achieves pulse compression ratio of NM. When an N/spl times/M MCPC signal is used in a coherent train of N pulses (e.g., in order to allow Doppler processing), it is advantageous to use pulse diversity. Each pulse is constructed using a different cyclic frequency shift of the first pulse. Such pulse diversity eliminates recurrent lobes at multiples of the pulse repetition interval. The constant volume property of the ambiguity function is maintained by shifting volume from the recurrent lobes to the sidelobe pedestal strips. However, if the sequence ordering along frequencies in the N pulses are arranged to create a complementary set in each frequency as well as in each pulse, the sidelobe level around the main autocorrelation lobe is dramatically reduced. Preferred MCPC coding for CW mode (contiguous MCPC pulses) and their delay-Doppler response are also discussed.