Research And Realization On Integrated Gravity/Inertial Navigation Algorithm Based On The Isoline

Inertial navigation system with the character of good covert and autonomous, can meet the navigation requirements of underwater vehicle to long periods sneak in blue water. However, the positioning error of inertial navigation system is proportional to the carrier transit times, what is difficult to adapt to the development of underwater vehicle, so it needs other methods of navigation to aid. To solve this problem, this paper conduct the research based on gravity aid navigation and positioning method, use passive navigation algorithm based on geophysical characteristics to complement of INS position error.Firstly, the paper describes the work theory and specific composition of gravity aided inertial navigation system, discusses the gravity aided inertial navigation algorithm as correlation analysis, iterative correlation contours, recursive filtering, analyze the performance of different algorithms, point that when INS location exists large error, the existing serial correlation matching method and recursive filtering method fitness or match precision have deficiencies. Secondly, considering the gravity aided navigation is the navigation method based on the gravity map, which is reached based on information database constituting of high-resolution gravity anomalies, so the article start the study from contour lines gravity digital map of the regular grid, and give contour generation method according to data sources, data grid, the equivalent point of resolving, tracking, search steps, provide the theoretical basis and technical means to the implementation of later algorithm.Because the existing matching algorithm in the process of calculation point to normal gravity, matching navigation system own an observation error. This paper proposes an implementation scheme which is a contour matching algorithm based on value function optimization to eliminate the system observation error. By the process of searching, tracking and decision-making, the most similar in shape between the search in prior gravity map and track provided by INS is the match. Simulation results show that:In normal sea conditions, contour matching algorithm provide high accuracy for the medium accuracy inertial navigation systems, improve the adaptability of existing algorithms and matching accuracy, can be used of underwater correction of great error in INS positioning.Finally, the paper use Microsoft Visual C 6.0 development environment and SQL Server 2000 database system to complete the contour matching algorithm, and give the key part of the algorithm implementation code, provides tools for the inertial navigation system position correction information extraction.