Analysis of FSK/PSK modulated radar signals using Costas arrays and complementary Welti codes

A novel method for generation of radar waveforms having both frequency shift keying (FSK) and phase shift keying (PSK) interior coding is considered. When PSK modulation is used in a pulse compression radar the radar bandwidth can be increased without increasing peak power. The range resolution is directly proportional to the coded pulsewidth. To achieve resolution in both range and velocity, the thumbtack property of the radar ambiguity function must be preserved. It is shown that by combining FSK and PSK modulation using Costas arrays and Welti codes a significant reduction in sidelobe values will occur. In addition, inherent combined spread spectrum characteristics yield a waveform with excellent ECCM properties