Comparison of the theoretical performance bounds for two wavefront curvature ranging techniques

The range focused beamformer (RFB) and the triple aperture crosscorrelator (TAC) are the two primary wavefront curvature ranging techniques used in fielded sonar systems. Theoretical performance bounds have been presented in the past for both approaches. This paper develops unified array processing performance bounds where the RFB and the TAC are special cases. Specifically, general Cramer-Rao lower bounds (CRLB) on range and bearing estimation for a linear array of directional elements are developed, where the CRLB for the RFB and the TAC are shown to be special cases of the general theory. The ranging performance of the two techniques are then compared