Non-coherent pulse compression - Aperiodic and periodic waveforms

The growing interest in adopting pulse compression waveforms to non-coherent radar and radar-like systems (e.g. lidar) invites this update and review. The authors present different approaches of designing on-off (1, 0) coded envelopes of transmitted waveforms whose returns can be envelope detected and non-coherently processed. Two approaches are discussed for the aperiodic case: (a) Manchester encoding and (b) mismatched reference. For the periodic case, on-off sequences are described, which produce perfect periodic cross-correlation when cross-correlated with one or more integer number of periods of a two-valued reference sequence (1, -b). This study provides comprehensive rules for designing periodic on-off waveforms and their references. The periodic waveform's high-average duty cycle (over 50%) makes it a 'quasi continuous wave (CW) non-coherent waveform', which avoids the pulse-train conflict between average power and unambiguous range. Good experimental results with a laser range finder are presented. Reports on other uses are quoted.