Underwater Navigation Terminal Algorithm Design And Engineering Implementation

Electromagnetic wave can not be transmitted in underwater long distance,it is difficult to use satellite navigation for underwater platform,and sound wave is the only information carrier that can be transmitted in underwater long distance,so underwater acoustic navigation is one of the important ways of underwater navigation.Conventional navigation in shallow sea uses mooring buoy as satellite station node,which cannot meet the needs of deep sea,so non-mooring satellite station with self-keeping ability should be used in deep sea.The real-time position of the self-positioning satellite station needs to be transmitted to the target to be navigated by means of acoustic broadcasting.The underwater navigation terminal on the target can acquire and process the positioning acoustic signals from multiple self-positioning satellite stations in real time to realize the deep-sea navigation function.This paper is devoted to the design of underwater acoustic terminal signal processing algorithm,complete the detection of positioning acoustic signals of self-monitoring satellite station,time delay estimation and real-time location acquisition of satellite station,targeted to solve the problems of Doppler,multi-path channel,channel interference,intercode crosstalk and other problems faced by signal processing,and carry out the engineering implementation of the algorithm.Firstly,the structure of positioning acoustic signal is given,and the detection and parameter estimation techniques of guide code and calibration code are studied.In order to solve the problem of robust and fast detection of boot code and calibration code,the frequency domain matching filtering algorithm is studied in this paper.In order to solve the Doppler migration problem caused by the dual maneuvering between the self-observant satellite station and the target,a Doppler compensation algorithm based on the instantaneous frequency of the correlation peak is studied to correct the delay estimation.For complex multi-path channels,the matching tracking channel estimation algorithm is studied in order to accurately estimate the channel balance when decoding the satellite station position.Then,the decoding technique of positioning acoustic signal in self-observant satellite station is studied.In order to realize the accurate transmission of coordinate information of position indication signal,the principle and method of information code modulation are studied.In order to solve the problem of increasing bit error rate caused by multi-channel decoding,a decoding method based on channel equalization is studied.In order to solve the problem of channel interference and inter-code crosstalk,a blind adaptive decoding method based on spread spectrum code division is further studied.By analyzing the performance of the above decoding methods,it is proved that the proposed method can reduce the bit error rate and improve the accuracy and stability of navigation.Finally,engineering implementation of the algorithm is carried out to complete the testing and performance analysis of real-time processing capability of engineering software.The paper gives the hardware platform design and real-time processing software algorithm flow,and carries out the software function test,gives the test analysis and navigation results of Qiandao Lake test and South China Sea test,and verifies the actual performance of the algorithm.