Digital LPI Radar Detector

The function of a Low Probability of Intercept (LPI) radar is to prevent its interception by an Electronic Support (ES) receiver. This objective is generally achieved through the use of a radar waveform that is mismatched to those waveforms for which an ES receiver is tuned. This allows the radar to achieve a processing gain, with respect to the ES receiver, that is equal to the time-bandwidth product of the radar waveform. This processing gain allows the LPI radar to overcome the range-squared advantage of the ES receiver in conventional situations. Consequently, a conventional ES receiver can only detect an LPI radar at very short ranges (<3 nm). The focus of this thesis was to develop an ES receiver to detect LPI radar signals with the same sensitivity as conventional pulse signals. It implements a detector which employs a technique, known as "deramping," that forms an adaptive matched filter to the linear FMCW LPI radar signal in order to achieve the processing gain that is equal to the received signal's time-bandwidth product. An experimental transmitter was built to emulate the radar signal with FMCW characteristics and transmitted through a standard gain horn. The transmitted signal is then received via a receiver horn, mixed down to an intermediate frequency (IF), sampled by an AID convertor and digitally deramped using a Pentium II computer. It was demonstrated that the LPI radar signal can be extracted from the noise background by means of digital deramping.Naval Postgraduate School Monterey CA is the author of 'Digital LPI Radar Detector', published 2001 under ISBN 9781423530794 and ISBN 1423530799.