Doppler Detection Capable Polyphase Good Code Sets Based on Linear FM Waveforms for MIMO Radar

Abstract

This paper introduces polyphase good code sets based on frequency-shifted linear FM (LFM) waveforms. It is shown that the entire set can be received using a single extended matched filter, constructed by extending the LFM slope on either side and can detect the higher energy distribution within the filter before summation (i.e., the Hadamard product). This higher energy distribution location gives the frequency shift that could identify a particular set member or the Doppler shift of an LFM based polyphase code. The result is Doppler detection of an LFM based polyphase code or detection of a polyphase good code set consisting of frequency-shifted LFM waveforms. The frequency offset between the different members of the set is chosen such that the Doppler shifts of the individual code members could also be detected. It is shown that such good code sets could be constructed with polyphase codes based on up- chirps and down-chirps of varying slopes, which would require a bank of extended matched filters, one for each slope.