磁偏角是使用电子罗盘进行航向测量的主要误差之一。受环境和传感器自身等因素影响，各地区的磁偏角真实值波动较大，导致电子罗盘测量航向角的精度难以保障。为提升精密工程测量中惯性传感器的精度，提出了一种GNSS定向与罗盘测向相结合的磁偏角快速测量算法。首先通过高精度大地坐标计算真北方位角和电子罗盘解算磁北方位角，建立基于多尺度解算结果的磁偏角估算模型；再借助最小二乘法磁场校正强化磁方位角计算对复杂环境的适应性；最后融合多个特定方位数据进行磁偏角精准解算。实验测试结果表明，该算法计算的各方位磁偏角数据基本稳定，校正后的倾斜补偿算法取得0.03 m的坐标改正精度；该算法在任意测量环境中均能快速、有效、准确的测量磁偏角。

Magnetic declination is one of the main errors of heading angle measurement by electronic compass. Influenced by factors such as environment and sensor itself, the true value of magnetic declination fluctuates greatly in various regions, leading it difficult to ensure the accuracy of heading angle measurement using electronic compass. In this study, a rapid measurement algorithm for magnetic declination by combining GNSS orientation and compass direction measurement was proposed to improve the accuracy of inertial sensors in precision engineering measurements. Firstly, the true north azimuth and the magnetic north azimuth were calculated via high-precision geodetic coordinate electronic compass respectively. Then, based on the fusion of multi-scale results, a magnetic declination estimation model was established, and the adaptability of magnetic azimuth calculation to complex environments was strengthened with the help of least squares magnetic field correction. Finally,multiple specific azimuth data was fused for accurate magnetic declination calculation. The experimental test results show that the magnetic declination data calculated by this algorithm is basically stable in all directions. After the magnetic declination correction, the oblique compensation algorithm calculated by this algorithm achieves a coordinate correction accuracy of 0.03 m. This algorithm can measure the local magnetic declination quickly, effectively and accurately in any measurement environment.