姿态检测用地磁图的线性样条组合插值算法

Linear Spline Combination Interpolation of Geomagnetic Map for Attitude Detection

针对双线性插值地磁图精度低的问题,结合地球磁场强度沿经线方向变化快、沿纬线方向变化慢的特点,提出地磁图的线性样条组合插值方法。该方法在经线方向上采用三次周期样条插值,在纬线方向采用线性插值的组合插值算法。以IGRF(国际地磁参考场)模型为参考依据,对线性样条组合插值进行的仿真和误差分析表明:线性样条组合插值法只需要7次加法和7次乘法便可以计算出地球磁场的分量,精度比双线性插值提高一倍以上,能够保证弹体滚转角检测系统实时准确地获取地球磁场信息。

To solve the problem of low accuracy of geomagnetic map with bilinear interpolation,according to the character of the field intensity which changes fast along longitude line and slowly along latitude line,the linear spline combination interpolation was put forward.The interpolation method adopted cubic periodic spline interpolation along the longitude line and linear interpolation along the latitude line.With the IGRF model,the simulation and analysis of combination interpolation showed that the linear spline combination interpolation only took seven additions and seven multiplications to calculate a geomagnetic component.And its accuracy was more than one time as high as that of bilinear interpolation.