Airborne Radar Ground Clutter Mitigation

Radar-guided medium-range missiles with look-down/shoot-down capability, such as AAMRAM, give the U.S. decisive air superiority over any adversary. However, low-flying targets provide a daunting challenge at beam aspect, where the target signal is embedded in high-amplitude ground clutter returns. Specialized signal processing techniques, such as STAP, reduce the impact of the mainlobe clutter, but they require multiple antenna apertures -— which may not be practical in missile applications -— and their effect is primarily to improve the signal-to-clutter ratio by ~30 dB, reducing the target’s MDV. But the closer target motion is to beam aspect, the less likely it is for its signal to be recovered from the mainlobe clutter signal. To address this problem, TSC is proposing an innovative technique, designated Target-in-Clutter Discriminator (TCD), whose aim is to discriminate the target signal in the presence of the much larger ground clutter signal, rather than to suppress the clutter signal, as done by existing clutter mitigation techniques. Additionally, angle measurement to the target is provided. To insure optimal processing conditions, appropriate waveform parameters are selected with the aid of DTED data. Initial estimates indicate moderate processor impact, although data compression may be needed for DTED, depending on the data’s region size.