Range sidelobe suppression of expanded/compressed pulses with droop

This report describes an investigation of range sidelobe suppression (SLS) for use with radar pulse expansion/compression. Specific consideration was given to SLS performance with no distortion, with measurable pulse droop and ripple, and with uncompensated Doppler shift within the pulse. Waveform codes considered included binary phase code, linear and nonlinear frequency modulation. In addition, continuous phase waveforms derived from binary phase codes were considered. A method of calculating coefficients for a sidelobe suppression filter was developed and tested. This method was used to generate two types of filters. First were sidelobe suppression filters, which are used in cascade to modify the compressed output of a pulse compressor. Secondly, it was used to generate “Inverse Filters,” which act directly on the expanded waveform to produce a compressed signal with suppressed sidelobes. Performance was quantified in terms of integrated and peak sidelobe level ratio, mismatch loss, and range resolution