基于等值线约束的地磁匹配方法

Contour Constraint Based Geomagnetic Matching Method

地磁辅助导航是组合导航技术研究的新方向.简要介绍了地磁辅助导航的基本原理和发展现状,并重点对地磁匹配方法进行了研究.地磁匹配是利用地磁图进行定位的方法,位置输出可用于限制惯性导航系统的误差积累.提出了一种改进的基于等值线约束的相关匹配算法,能够有效消除导航系统的初始位置误差并能限制匹配过程中惯性导航系统的积累误差.仿真实验证明,该算法能有效提高相关匹配的实时性,并能把定位精度控制在地磁数据网格间距以内.该算法对航向误差具有一定的适应性.

Geomagnetism Aided Navigation （GAN） is a new branch of the integrated navigation technique. Navigation principle and the development of the GAN system are introduced in the paper. The emphasis is laid on the research of the matching method. Geomagnetic matching is the technique that uses a geomagnetic map to determine the location of the vehicle. The obtained position information can be used to limit error accumulation of the Inertial Navigation System （INS）. An improved correlation matching method based on the contour constraint is proposed. Map contour is used to confine the searching process, changing the uncertainty field to an uncertainty line, which efficiently reduces the computation burden of the system and eliminates the initial position error of INS. A nearest point principle （NPP） is applied in the precision matching part. The NPP technique can bind the error of INS accumulated during the matching process. The simulation results show that the proposed method can greatly improve the efficiency and precision of the whole GAN system. The accuracy of the matching method is less than the unit cell size of the map. In addition, the proposed method is, to some extend, adaptive to the heading error of the INS.