低成本动中通姿态估计算法

An Attitude Estimation Algorithm for Low-Cost Satcom On-The-Move

针对低成本微机电惯性测量单元无法满足宽带移动卫星通信系统姿态估计精度的问题,提出了以单基线GPS为辅助敏感器的改进型非线性观测器姿态估计算法。与经典观测器相比,改进算法利用观测器估计姿态代替加速度计估计姿态计算北向矢量的观测矢量,有效解决了加速度计精度与单基线GPS精度不匹配的问题。在单基线GPS不能正常工作的状态下,设计了状态判断开关,成功减少了载体机动加速度对估计结果的影响。试验结果表明:在单基线GPS一直正常工作的条件下,设计的改进非线性观测器的姿态估计精度达到±0.5°;在单基线GPS不能一直正常工作的情况下,在GPS可见弧段其姿态估计精度也达到±0.5°,均优于传统非线性观测器,满足低成本动中通要求。

A modified nonlinear observer assisted by single baseline GPS is proposed to solve the problem that the accuracy of the low-cost micro electromechanical system （MEMS） inertial measurement unit （IMU） cannot satisfy the requirement of the broadband mobile satellite communication system for attitude estimation accuracy. Compared with the classical nonlinear observer, the proposed modified nonlinear observer substitutes the attitude angles estimated by the observer for attitude angles acquired by accelerometers to calculate the north vector. This can solve the problem of mismatching between accuracies of accelerometers and single baseline GPS. When the single baseline GPS cannot work properly, a state switch is designed to remove the non-gravitational component of the aeeelerometers and isolate the interference of vehicle＇ s motion. Experimental results show that the proposed modified nonlinear observer has better performance than classical nonlinear observer and can provide the estimated attitude angles with an accuracy of ＋ 0.5° when single baseline GPS works normally all the time or an accuracy of ~ 0.5 ° during the non-blockage intervals when single baseline GPS cannot work normally all the time.