Sensitivity of a passive horizontal‐tracking algorithm to input‐measurement errors

Abstract

We consider the passive determination of bearing, range, depth, frequency, and horizontal velocity for a narrow‐band acoustic source which moves at constant depth. An algorithm for tracking a moving source is developed and employed, using a horizontal linear array which is towed at fixed depth. The source and receiver move with constant horizontal velocity in the upper portion of a deep ocean and are separated by relatively short range. Acoustic signals are presumed to arrive along two upper‐ocean ray paths. The tracking is accomplished using a new combination of processed multipath information from the ray paths, frequency shifts from a cw emission, and directional meaurements from the linear array. The sensitivity of predictions for three‐dimensional position, frequency, and horizontal velocity are demonstrated for small variations in environmental parameters and acoustic measurements. Results for a variety of source‐receiver configurations are discussed. Variance estimates of position and motion predictions are obained in terms of input measurement variances. [Work supported by ONR.]