Cramer-Rao bounds for target angle and Doppler estimation with space-time adaptive processing radar

Space-time adaptive processing (STAP) can substantially improve airborne radar performance in environments with interference (clutter and/or jamming). This paper considers target parameter estimation with the STAP radar. The maximum-likelihood estimator for target angle and Doppler is reviewed. 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 the target Doppler and vice-versa. They are useful for quantifying the best-case degradation in estimator accuracy due to interference, and for determining the fractions of the Doppler space and coverage sector over which a specified level of accuracy can be achieved.