Gravitational Field And The Geomagnetic Field Aided Inertial Navigation Technology Research

Underwater tools, such as submarine, need to be hidden underwater for a long time when they are navigating, so they depend on passive navigation systems heavily. There is a hot point at the present stage that using earth's own physical fields to assist inertial navigation systems for the theories and methods of passive navigation. It has been regarded by many institutions and scholars at home and abroad, while gravity-assisted navigation and magnetic-assisted navigation are important research direction in this field.Both gravity assisted navigation systems and geomagnetism assisted navigation systems are based on matching map, the errors of inertial navigation systems are limited by those information form gravitational field and geomagnetic field, and then the precision of the navigation systems will be maintained with the demand in advanced. They have three similar elements: instruments, maps and matching algorithms. Thereamong, matching algorithms is the core in whole assisted navigation system.The researches that focus to correct the errors of inertial navigation system with only assistant information was the mainstream in navigation field over the past several decades. With the development of those interrelated technologies and theories, in the navigation field, it has been the important direction that improving the precision of inertial navigation systems with the assistants of several earth own physical fields. At the same time, the tridimensional navigation researches are developed step by step in three-dimensional space, it was regarded the direction of navigation, so more and more sources are launched into the fields.In the paper both gravity-assisted navigation and magnetic-assisted navigation were assisted to inertial navigation system in two-dimensional plane, and then it is expanded into three-dimensional space. Firstly, digital gravity map is used to be the main matching information for the goal that researching the mathematical mechanism of ICCP. Quaternion is introduced to solve the conditions of goal function extremum. The fundament and the realization are showed here. Secondly, in ICCP algorithm using magnetic map information to limit the choice of nearest point that are in the gravity isolines to improve the navigation precision, and then expanding the method into three-dimensional space by projection after those two hypotheses was met. Finally, the software was programmed while some tests were designed to produce the results. Through analyzing those results, it is proved that the precision of passive navigation system was improved by the method of both gravity map and magnetic map were assisted to inertial navigation system, while it can been expanded into three-dimensional space.