Patent ID: 8270252

Claim:
A method for estimating a target range error in an active sonar system, the method comprising: (a) setting a search range boundary (R s ) of a target for range error estimation, under initial conditions of a one-way target detection time (T sonar ) and a detection target range (R sonar ) detected by an active sonar; (b) inputting environmental data of an area where the target is located; (c) predicting a multipath eigenray time (T path (i,j,k)) and a multipath eigenray pressure (P path (i,j,k)) at each multipath (k), range (j) and depth (i) within the search range boundary (R s ), by detecting multipath eigenrays reflected from the target; (d) filtering the detected multipath eigenrays so as to extract a time (T path (i,j)) of a dominant pressure path or a first arrival path among the predicted multipath eigenrays; (e) searching, at each depth, a horizontal range (R(i)) corresponding to a matching time (T path (i)) that the filtered dominant or first arrival path time (T path (i,j)) matches the detected one-way target detection time (T sonar ); and (f) calculating a target range error (R error (i)) between the searched horizontal range (R(i)) corresponding to the matching time (T path (i)), and the detection target range (R sonar ) calculated based on the detected one-way target detection time.