DSP Software Design Based On USBL Broadband Signal Positioning Algorithm

Ultral Short Base Line Positioning System (USBL) is an acoustic positioning system,which realize positioning, tracking and data transmission to underwater cooperative targets. The system generally works in response mode. The key technologies are how to realize the real-time signal detection and target azimuth accuracy estimates.This article is composed of three parts : research and simulation of USBL positioning algorithm; design and implementation of digital signal processing software; tank experiments and lake experiments.In recent years, ultra-short baseline positioning products are developed to broadband direction generally,on the purpose of achieving the anti-multi-path and improvig processing gain. In this paper, correlation time delay estimation and three cosine interpolation fitting method are used for broadband singnal positioning algorithm. But ordinary Multiply-Accumulates have large amount of calculatoin and are too slow to meet requirements of real-time processing. A fast FFT-based sliding correlation method is used in this paper, which use high-performances of DSP in FFT computation to solve the problem of real-time processing. On this basis,with the combination of envelope detection and correlation peak interpolation techniques,a simulation program of real-time signal detection and targeting is designed. Algorithm through Matlab simulation results show that the method can be at a lower SNR to achieve a higher positioning accuracy.Realization of signal processing software is designed on the hardware platforms which is based on two TMS320C6416DSPs. Correlation time-delay estimation techniques are used to implement positioning algorithm of USBL. In addition, a system of signals processing is completed,which can realize the real_time detection and time_delay of broadband response signal, Geodetic coordinates of the target real-time solver. Finally, the tank and lake experiments are carried out to verify the feasibility of the location algorithm, while the stability and reliability of system's hardware and software are checked too.