水下地磁辅助导航中地磁场延拓方法

水下地磁数据库的构建是实现地磁辅助导航的前提。利用水下航行器进行地磁测量从而建立水下地磁数据库,这种做法是不可行的,一种可行的解决方法是采用位场的延拓技术。采用位场的向下延拓技术,通过将海平面上航空测量得到的地磁数据进行向下延拓,得到水下地磁数据,以此来构建水下地磁数据库。将位场的向下延拓问题视为一类不适定问题,采用正则化方法中的Landweber迭代法来处理这类不适定问题,实现了地磁数据的向下延拓。仿真结果表明,该方法原理简单,抗噪声能力强,能够得到比较满意的延拓结果。

Technique of geomagnetic field continuation in underwater geomagnetic aided navigation

The building of underwater geomagnetic database was the premise of realizing geomagnetic aided navigation.but it is not feasible to build the database by the geomagnetic survey with underwater vehicle.One feasible method is to adopt the continuation technique of potential field.By downward continuation of potential field, aeromagnetic data above sea level could be downward continued to get geomagnetic data underwater,then underwater geomagnetic database could be build.The problem of downward continuation of potential field could be considered as a type of ill-posed problems.The Landweber iteration method,one of regularization methods,was used to deal with these problems,and the downward continuation of geomagnetic data was realized.Simulation show that this method,based on a simple principle,has high anti-noise performance,and the continuation result is satisfying.