Research On Terrain Aided Navigation Technology Of Underwater Vehicles

Ocean has become an important strategic goal of various countries in recent years,and navigation systems are indispensable key components in the fields of underwater resource exploration,mining,and transportation.The terrain-aided integrated navigation system is taken as the research object,and research focuses are the modeling of terrain and water depth data,the improvement of terrain matching algorithm and the error correction technology of integrated navigation,aiming at improving the final positioning accuracy of the integrated navigation system.The main work is summarized as follows:(1)The related concepts of the integrated navigation system based on terrain assistance are analyzed,the state space model of the terrain aided navigation system and the factors affecting the performance of the system are given Three typical algorithms are used as examples to introduce the terrain matching methods and their advantages and disadvantages.(2)An overview of the digital ground model is given,and the common model description methods are introduced.For parametric interpolation and semi-parametric interpolation modeling,the corresponding expressions and implementation principles are given.Then the principles and implementations of the Gaussian process are analyzed in detail method.A Gaussian process based on adaptive natural gradient is proposed,and its mathematical principle and algorithm flow are explained.Using real water depth data interpolation modeling,comparative analysis shows that the modeling accuracy of adaptive natural gradient Gaussian process is higher than all other interpolation algorithms.And the time-consuming is about 20%less than the Gaussian process method,where the real-time performance is improved.(3)Taking the iterated closest contour point(ICCP)algorithm for terrain matching as the research object,the principle of the traditional ICCP algorithm is explained.It is analyzed that the velocity error brings affine errors that cannot be eliminated by rigid transformation,and the affine model is introduced to compensate this error.An improved ICCP algorithm based on affine factor compensation is proposed.The analytical solution form of the affine factor is derived,and the process of the improved ICCP algorithm is introduced.Based on the real water depth and different tracks,a comparative experiment is designed to verify the proposed algorithm.The results show that the improved ICCP algorithm can improve the matching accuracy by about 70%-80% under the premise that the time-consuming increase is less than1%.(4)For the terrain-aided loosely integrated navigation model,the traditional Kalman filter is introduced.And it is analyzed that the time-consuming of terrain matching which can not be ignored leads to the delay error.Then an error correction method based on the delay state recursion is proposed.The error correction filter is introduced.The technical implementation process and its state equation and measurement equation are given.Comparing the results of traditional Kalman filtering and delay recursive Kalman filtering,it can be found that the delay recursive error correction technology can compensate for the delay error,and the final total position error is reduced by 15.2%.