无人机磁航向测量的自动罗差补偿研究

Study on Automatic Magnetic Deviation Compensation of Magnetic Heading Measurement for UAV

利用地球磁场测量无人机的航向时,需要对机上铁磁材料引起的罗差进行补偿。为了降低补偿费用,减小补偿试验时周围环境的影响,提出一种利用飞机左右盘旋飞行时采样数据实现罗差自动补偿的方法。采用椭圆假设算法,可利用飞机平飞时在多于5个不同方向的采样数据来自动补偿平飞时的罗差。在任意姿态飞行时,把飞机左右盘旋时采样的数据分解为4个椭圆,并求出它们相对于椭圆假设的24个系数。再利用这24个系数和飞机的俯仰角、倾斜角以及地磁场垂直分量求出任意姿态下罗差补偿所需的12个系数。实验结果表明,该方法效果良好,方便可行。某无人机补偿前最大误差为21.5°;用传统方法补偿后最大误差为2.3°;用本文方法几乎不需要额外的费用,补偿后最大误差为1.6°。

In magnetic heading measurement of unmanned aerial vehicles （UAV）,it is necessary to compensate the magnetic deviation caused by ferro-material onboard UAV. In order to lower the compensation cost and avoid the influence of surrounding ferro-material,an automatic compensation method is put forward, using the data sampled while the UAV circles in the air. Using ellipse hypothesis,one can only compensate the deviation for UAV flying in horizontal plane by the data sampled while UAV flying in more than 5 directions. When UAV flies in all possible attitudes,the relationship of sample data is descriped by 4 ellipses,and 24 coefficients are got by ellipse hypothesis. Using these 24 coefficients,the vertical component of earth＇s magnetic field and the pitch and roll angles of UAV, the 12 coefficients needed to compensate the magnetic deviation in all possible attitudes are obtained. The experimental results conform the validity and feasibility of the method mentioned. The maximum heading error of an UAV is 21.5° before compensation,and it becomes 2.3° by using a traditional method and becomes 1.6° by using the new method without almost compensation cost.