Research On Long Range Utral Short Baseline System

Acoustic positioning system has wide application in Ocean Scientific field. However, existing systems have disadvantages of bulkiness, perplexing operation, limited position range and low precision, resulting in their incompetence of satisfying many application needs. With the development of Acoustics and Signal Processing theory, as well as that of DSP and DGPS technology, it is possible for us to develop more advanced positioning systems.The main work of this thesis includes: system level design and implementta-tion of an Long Range Ultra Short Baseline (LR-USBL) system that is one of research projects of the Natural 863 program, research and design of the calibration of the phase shift misalignments of the baseline array , angular misaligments of the USBL sensors, and performance verification by experiments.System architecture design is crucial to a system's performance. Our system is composed of acoustic vessel-born localization system, measuring vessel heading and attitude system, and measuring vessel position system. Among others, baseline array structure is one of its innovations, which enables it to position targets in long range with high precision. This thesis analyses the error source of the system, and introduces the algorithm of the high precision position. Others discussed in the thesis include structure design of array and responder, the architecture of the transceiver unit and controlling application of system.According to error analysis, it is key to restraing the direct measuring errors for increasing system positioning precision besides improving the input Signal-to-Nosie Ratio. The thesis introduces some methods for reducing the phase measuring errors and increasing positioning precision from three aspects: high precision positioning algorithm, calibration of the phase shift misalignments of the baseline array, and at-sea calibration of the LR-USBL system.As we known, USBL aperture size is small and it is easy to install. However,...