Statistical Performance Prediction of Generalized Monopulse Estimation

Monopulse is an established array processing technique for fast and accurate angle estimation. This technique has been generalized to space-time array processing of any dimension. The statistical performance of this generalized monopulse parameter estimation has been characterized for several target fluctuation models but not for all cases. This gap is filled by this paper. We derive the mean and variance of the complex and real and imaginary part of the averaged monopulse ratio for all Swerling target models, deterministic targets (Swerling 0 case), χ² distributed targets with 4 degrees of freedom (Swerling 3 or 4 case) including a given detection threshold, for an arbitrary number of difference beams, and for an arbitrary number of noncoherent averaging of time snapshots. For completeness we give also the already known results for Rayleigh targets (Swerling 1 or 2 case) in the same notation. From these means and variances, the performance of all kinds of parameter estimates with the generalized monopulse formula can be calculated. Applications of these statistical descriptions are presented for planar arrays and adaptive beamforming and for space-time adaptive processing (STAP) for broadband interference suppression. From these examples some interesting conclusions can be drawn.