﻿ 基于半实物仿真的地磁导航等值线匹配算法评估
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Evaluation of ICCP algorithm for geomagnetic navigation based on hardware-in-the-loop simulation
WANG Shicheng , LÜ Zhifeng, ZHANG Jinsheng, LU Zhaoxing
Precise Guidance & Simulation Technology Lab, The Second Artillery Engineering University, Xi'an 710025, China
Abstract:The performance of geomagnetic navigation matching algorithm is influenced by many factors. However, the evaluation of algorithm is completely based on computer simulation at present, whose credibility should be validated further. The iterated closest contour point (ICCP) algorithm was studied. First, the factors were analyzed theoretically, which affect the performance of algorithm. Then, the hardware-in-the-loop simulation system of geomagnetic navigation was established. Geomagnetic field simulation environment and magnetic sensor were introduced in the system and the credibility of simulation was improved. Finally, the performance of algorithm was analyzed from measurement noise, matching length, matching region and inertial navigation system (INS) errors based on the hardware-in-the-loop simulation system. The simulation results show that anti-interference of the algorithm, determination of matching length, selection of matching region and influence of INS errors can be evaluated effectively through the hareware-in-the-loop simulation experiments. The method of hareware-in-the-loop simulation can promote the engineering process of geomagnetic navigation and ICCP algorithm.
Key words: geomagnetic navigation     iterated closest contour point (ICCP) algorithm     geomagnetic field simulation environment     hareware-in-the-loop simulation     algorithm evaluation

1 地磁导航匹配算法 1.1 ICCP算法原理

ICCP算法基于几何学原理,它的实质是匹配多边弧.它的匹配过程基于寻找最近等值线点,用最小方差估计的方法,通过计算测量点与真实位置点之间的刚性变换(包括旋转和平移),经过多次迭代,使得两弧之间的量测距离不断减小,从而得到最优估计航迹,其原理图如图 1所示.

 图 1 等值线(ICCP)算法原理示意图Fig. 1 Principle of iterated closest contour point (ICCP) algorithm

 图 2 等值线(ICCP)算法流程图Fig. 2 Flow chart of iterated closest contour point (ICCP) algorithm

1.2 影响ICCP算法性能的因素分析

1.2.1 测量噪声

1.2.2 匹配长度

1.2.3 匹配区域

1.2.4 惯导误差

2 地磁匹配导航半实物仿真系统构建

 图 3 地磁匹配导航半实物仿真系统Fig. 3 Hardware-in-the-loop simulation system of geomagnetic matching navigation

3 仿真试验

 图 4 地磁基准图Fig. 4 Geomagnetic reference map
3.1 测量噪声对匹配算法的影响

 图 5 加入不同测量噪声的匹配结果Fig. 5 Matching results of different measurement noise

3.2 匹配长度对匹配算法的影响

 图 6 不同匹配长度的匹配结果Fig. 6 Matching results of different matching length

3.3 匹配区域对匹配算法的影响

 匹配区域 匹配成功次数 路径1 18 路径2 0

3.4 惯导误差对匹配算法的影响

 图 7 不同惯导位置误差的匹配结果Fig. 7 Matching results of different inertial navigation system (INS) position errors

 图 8 不同惯导航向误差的匹配结果Fig. 8 Matching results of different inertial navigation system (INS) heading errors

4 结 论

1) ICCP算法原理是正确的,能够对惯导的偏差予以修正.但是其抗干扰性比较差,要想应用于工程实际中,必须建立较为精确的载体干扰磁场补偿模型以保证测量值的准确性.

2) 匹配长度对算法有影响,但并不是越大越好,在有限的匹配区域内,应综合考虑匹配成功概率和匹配次数,通过更接近实际情况的半实物仿真试验,做出折中的选择.

3) 匹配区域的选取对算法的性能影响较大.应尽量选取磁场差异性较大的地区作为匹配区域,以提高算法的抗干扰能力.

4) 惯导位置误差对算法的影响不是很明显,但惯导航向误差对算法影响较大,因此工程实际中应在保证航向误差不是很大的情况下使用该算法.

#### 文章信息

WANG Shicheng, LÜ Zhifeng, ZHANG Jinsheng, LU Zhaoxing

Evaluation of ICCP algorithm for geomagnetic navigation based on hardware-in-the-loop simulation

Journal of Beijing University of Aeronautics and Astronsutics, 2015, 41(2): 187-192.
http://dx.doi.org/10.13700/j.bh.1001-5965.2014.0117