Study On Beamspace High-resolution Direction-finding Methods

It is well known that Array Processing Technique is a main branch of underwater acoustic signal processing and multi-target parameter estimation. Meanwhile, high-resolution technique is an important aspect of array processing. Aiming at application in engineering, the beamspace high-resolution direction-finding theory, methods, and important problems in realistic scenarios are studied in this paper. Main research results and achievements are summarized as follows:1. The element-space high-resolution direction-finding methods are disserted. The formulas for the MUSIC, Mini-Norm, Root-Music, ESPRIT and MODE methods and the calculation procedureares are discussed. The integrated performance evaluation indexes are presented. According to these indexes, the performances of the aforementioned element-space methods are analyzed. Based on the analysis, the practicability of the methods is evaluated.2. The beamspace high-resolution methods are studied. On the basis of theoretical study, large amount of computer simulation and statistical analysis are conducted to investigate the performance of the beamspace methods. It is shown that the beamspace methods possess higher resolution probability than the corresponding element-space methods. Significantly the BRoot-Music, BMUSIC and BMini-Norm reduce the RMSE. Comparing with the other three beamspace methods, the BMODE and the BRoot-Music possess superior resolution performance. In the meanwhile, the BMODE is studied further. Its angular resolution ability under different SNRs is summarized comprehensively. The effects on its performance by the factors such as snapshots and number of array sensors are investigated and their relations are also quantitatively analyzed.3. The performance of multiple beamforming system and high-resolution methods are studied when the powers of sources are different. It is shown that high-resolution methods are not sensitive to the power difference of sources and so possess superior resolution ability over beamforming methods in this condition. Meanwhile the beamspace high-resolution methods possess better resolution performance than the element-space high-resolution methods in the condition. The BMODE method and the BRoot-Music method show the best resolution performance among the five beamspace methods.