Principles of Modern Radar - Volume 2 1891121537

Clutter Suppression UsingSpace-Time AdaptiveProcessingWilliam L. MelvinCHAPTER10✬Chapter Outline10.1 Introduction ................................................................... 45310.2 Space-Time Signal Representation ............................................ 45910.3 Space-Time Properties of Ground Clutter ...................................... 47210.4 Space-Time Processing ....................................................... 47410.5 STAP Fundamentals ........................................................... 47810.6 STAP Processing Architectures and Methods .................................. 48310.7 Other Considerations .......................................................... 49110.8 Further Reading ............................................................... 49310.9 Summary ...................................................................... 49310.10 References .................................................................... 49410.11 Problems ...................................................................... 496✫✩✪10.1 INTRODUCTIONMoving target indication (MTI) is a common radar mission involving the detection ofairborne or surface moving targets. The signal-to-noise ratio (SNR)—a characterizationof the noise-limited performance of the radar against a target with radar cross section σ Tat range r—is approximated as( )( )( )Pt G t (φ,θ) σT Ae G spSNR(φ,θ) =(10.1)4πr 2 4πr 2 N in F n L rfwhere P t is peak transmit power, G t (φ,θ) is antenna gain at azimuth φ and elevation θ,A e is the effective receive aperture area, G sp represents processing gains, N in is the inputnoise power, F n is the receiver noise figure, and L rf represents radio frequency (RF) systemlosses [1]. Assuming the noise is uncorrelated (white) and Gaussian, the probability ofdetection is a one-to-one, monotonic function of both SNR and probability of false alarm: bymaximizing SNR, the processor maximizes probability of detection for a fixed probabilityof false alarm. In light of (10.1), the radar designer ensures detection of targets withdiminishing radar cross section at farther range by increasing the power-aperture product,P t A e . System constraints and cost limit the deployable power-aperture product.453