Research On Underwater Geomagnetic Aided Navigation

The science of navigation is one of the key technologies for Underwater Vehicles. The accuracy, continuity and real-time properties of navigation device are regarded as vital factors concerned the successful completion of certain assignment of AUV. As a main measurement technology for underwater navigation, INS (Inertial Navigation System) has not been used widely due to its high price, as a result, low cost assistant forms of navigation are receiving more and more attentions recently. Therefore the alternative is to make use of the information of topography, gravity field, geomagnetic by geophysical survey, which can be served as an ideal way for high-precision and all-weather navigation. Using underwater geomagnetic information aided inertial navigation can ensure the requirements of system stability, high precision and high reliability, which has become an indispensable means of navigation and positioning in developed countries.In this paper a simple introduction about the development of underwater navigation methods,including inertial navigation, acoustic navigation, geophysical development of navigation and integrated navigation was presented firstly, and also their existing technological problems that have not yet been solved were pointed out. Then, the critical sections of magnetic-assisted navigation technology were demonstrated, which includes geomagnetic field modeling, matching magnetic graph generation and developing matching algorithm.2D Taylor polynomial model of undersea local area was established, and the principle and steps of modeling process were presented in a comprehensive manner. By using potential field extension technology,3D model of undersea local area was also developed. For the requirement of high-precision of geomagnetic matching, polynomial interpolation, inverse distance power law method and Kriging approach were all used to optimize geomagnetic maps respectively, and comparative results and improvements of these methods were given.Finally, the basic principle and progress of shape matching algorithm developing were presented. Detained analysis on the contour extraction, nearest point of contour line searching and rigid transformation was conducted. Focus on the processing of anti-error iterations, novel solutions were found out. The simulation results verify that referenced navigation system with underwater geomagnetic aided navigation has a superiority over the precision of navigation, and a quantitative analysis about the precision of navigation was carried out based the simulation results.