| Popis: |
Matched‐field processing (MFP) is being considered increasingly for three‐dimensional (3‐D) localization of an acoustic source in a noisy ocean environment. MFP consists of comparing the measured acoustic field to the full field computed using a geophysical and a propagation model. Most MFP implementations have involved only range‐independent propagation models, and many have been restricted to vertical arrays. However, many realistic environments cannot be adequately described by range‐independent models, and the problem of localization using more general arrays is of increasing interest. In this paper, a technique is described for range‐dependent MFP with arbitrary arrays, where the field is computed using a parabolic equation (PE) approximation. Using PE, two‐dimensional (2‐D) field values are computed for each sensor in the array for a set of possible source ranges, depths, and (N) bearings to form an N×2‐D field model. Discrete estimates of the position of the source are obtained by applying MFP, with this range‐dependent model providing field values at the sensors for possible source positions. Using simulated data, source localization in a noisy range‐dependent environment is illustrated for several arrays. For the particular cases studied, a lower level of ambiguity was observed for range‐dependent MFP than for a related range‐independent problem. The use of range‐dependent models in MFP should significantly improve array design and analysis of real data from many locations. |
