Constrained Time Delay Estimation Via Zero-Crossing Methods

A constrained processor (CP) for time delay estimation is presented which employs a predefined set of candidate log-likelihood score functions. In spatially white ambient noise, the CP can achieve nearly minimum variance time delay estimates without a priori knowledge of the receiver input statistics. As applied to the split-beam correlator, a constrained interference rejection structure is proposed to facilitate robust sub-optimal target bearing estimation.