地磁适配性BP评价方法的初始权因子确定

Study on Initial Weight Factor of BP Evaluation Method for Geomagnetic Positioning Adaptability

区域地磁的适配性评价是地磁匹配定位导航的基础,针对地下工程带状空间、地磁BP样本数量较少的特点以及传统BP网络的缺陷,文中选用回归分析、信息熵分析和偏最小二乘分析(PLS)对地磁空间分布特征指标进行定权,建立了基于贡献权因子BP的井下地磁适配性评价方法。试验选取45个人防工程的地块样本,在计算粗糙度等7个地磁空间分布特征指标的基础上,进行了4种贡献权因子的BP适配性评价的精度对比。结果表明,基于熵权与等价权的BP网络识别准确率大致相同,但训练时间较长;偏最小二乘法BP网络结构简单且收敛迅速,但准确率较低;基于多元回归的BP的评价方法的准确率最高且训练时间较短,不易陷入局部最优,较适合作为地磁适配性BP评价方法初始权因子的优选方法。

The adaptability evaluation is the basis of geomagnetic matching positioning and navigation in regional area.In this paper,a geomagnetic adaptability evaluation method which is based on contribution factor BP is established.45 samples of the underground projects were selected,and 7 geomagnetic spatial distribution characteristics were calculated like roughness to carried out the experimental of the accuracy comparison of BP suitability evaluation which are based on the four weighted calculation schemes.The results show that the accuracy of BP network based on entropy weight and equivalence is approximately the same,but the training time is longer;The accuracy of the partial least squares BP network is low though it has simple structure and fast convergence;The BP evaluation method which based on multiple regressions that has the highest accuracy and short training time,and it can avoid falling into local optimality to some extent,and it is more suitable as the preferred method for the initial weight factor of the geomagnetic adaptive BP evaluation method.