Maximizing noise-limited detection performance in medium PFR radars by optimizing PFR visibility

Abstract

Many modern air-to-air radars use medium pulse repetition frequency (PRF) as a principal operating mode. The ambiguities of the range and Doppler measurements inherent in medium PRF are resolved by switching between several carefully selected PRF values during the beam time on target. To achieve the desired detection performance and maintain an acceptable false-alarm rate, medium PRF radars typically employ a double-threshold detection scheme. This requires M correlated detections out of N PRF dwells during any single antenna beam position. The N PRF values are selected to avoid blind zones in range and velocity. Blind zones are regions in range-Doppler space where targets cannot be detected due to blanking for the transmission of the pulse, or main-beam ground clutter. The main-beam ground clutter varies in power, frequency, and range as a function of the radar's relative velocity, altitude, and antenna look angle. Advanced fighters are expected to perform against all aspect targets at a wide range of altitudes and speeds. performance in most conditions. The goal of this paper is to examine the effect that an adaptive PRF selection algorithm would have on the noise-limited performance of the radar. The algorithm would optimize PRF visibility by adapting to the changing blind zones. The results show that this simple algorithm can significantly increase the probability of detection for a given signal-to-noise ratio in many scenarios. >