Space/time/frequency methods in adaptive radar - New Jersey ...

70where x is the data vector, s is the steering vector, and R is the covariance matrix.To use the technique with a fixed transform such as the discrete Fouriertransform (from Equation 2.4) or the discrete Cosine transform (Appendix A), theK terms in the transform are selected based on the amount of 'energy' associatedwith each index. This is done by computing a 2-dimensional stacked transform(Appendix B) ST and calculating the N termsThe columns of ST terms associated with the largest K results of this calculationsare defined as T². Finally, the transform matrix T is defined asThe inclusion of s within the transform matrix constrains the system so that3.3 Target CancellationTarget cancellation occurs when the target signal is present during training, when theestimation of the noise covariance matrix occurs and also when there are calibrationerrors. In the case of the steering vector being mismatched to the signal vector, thearray cancels the target as it is interpreted as an interference. If the true covariancematrix is know, the signal cancellation may be isolated from the noise covariancematrix estimation effects. This case may be shown to be true when the weightvector is applied to the data it was derived from.The correlation matrix of a N element spatial processor with a single interfererand a single target is