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Angle and Doppler
Estimation with
Space-Time Adaptive
Processing Radar

James Ward
MIT Lincoln Laboratory
244 Wood Street
Lexington, MA 02173-9108
tel: (617) 981-0617
email: jward@ll.mit.edu

Abstract The benefits of space-time adaptive processing (STAP) for improved interference suppression and target detection are well established. This presentation considers target parameter (angle and velocity) estimation with an airborne radar employing STAP. Cramer-Rao bounds for target angle and Doppler estimation accuracy are derived for an arbitrary interference scenario. These bounds show that in clutter, angle accuracy depends on Doppler and vice-versa. The bounds also provide the portions of the Doppler space and coverage sector over which a specified level of accuracy can be achieved. The maximum likelihood (ML) estimator is examined. A computationally efficient approximation to the ML estimator is developed and applied to several STAP architectures. Simulation results are presented and compared with the Cramer-Rao bound. It is shown that for targets close to the clutter ridge, the new estimators provide significantly better accuracy than conventional angle and velocity estimators that only utilize one-dimensional information after initial STAP detection.



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