Demonstration of Advanced Detection Techniques Against Low Probability of Intercept Avionics Waveforms

The objective of this proposed Phase 1 effort is to develop and simulate a realizeable design for a receiver-signal processor that detects, finds the direction of arrival, and correctly identifies weak signals from radar altimeters. The effort extensivelymodels and predicts the operational system's detection sensitivity, direction finding accuracy and identification accuracy against frequency modulated coninuous wave (FM/CW) signals under realistic conditions. The ultimate goal is a system detectionsensitivity of less than -118 dBm, azimuth angle arrival accuracy less than 1 degree, and indentification accuracy greater than 95%. Novel signal feature detection algorithms and efficient digital signal processing implementations show significantpromise for achieving these goals in operational systems. High azimuth accuracy is achieved using unique interferometric feature detection techniques for very low SNR signals in wide input bandwidths. The proposed techniques discriminate againstinterference, parameterize the waveforms, and identify them through their unique parameter sets. Software simulation of signals and detection processing are necessary steps in establishing confidence in these techniques for a variety of FM/CW waveformsand interference conditions. Detection of pulsed altimeter signals will also be investigated. Simulations will be compared with performance predicted by theory.Improved communications system performance by being able to detect low powered signals orweak signals at longer ranges. May apply to CDMA format communication signals such as used in cell phone systems.