两种多天线GNSS定姿方法的精度分析

Analysis on precision of two attitude determination methods using GNSS multi-antenna data

基于高精度多天线GNSS基线分量及精度估计结果,实现了两种常用的多天线定姿方法:直接姿态法和最小二乘姿态法。利用一套车载三天线GNSS实测数据和高精度惯性导航系统(陀螺漂移0.005(°)/h,加速度计零偏优于10^(-3)g)输出的姿态结果,深入分析了两种定姿方法的内、外符合精度。实验结果表明:两种定姿所解算的航向角、俯仰角和横滚角的精度分别为:直接法的内符合精度约为0.3°~0.5°、0.3°~1.0°、0.5°~1.0°,最小二乘法约为0.1°、0.2°~0.5°、0.5°~2.0°,即最小二乘法对航向角估计有明显改善,对俯仰角和横滚角改善不明显;两种方法的姿态外符合精度(消除航向系统偏差)基本一致,约为0.08°、0.15°、0.42°,但是最小二乘法得到的航向角系统偏差更小。

With the use of precise baseline vectors and their variance estimators, calculated using the GNSS multi-antenna data, two classic attitude determination methods, i.e. the direct method and the Least Square（LS） method, are investigated. The numerical results achieved by the above two methods are analyzed with a set of three-antennas on-board GNSS data. This is done by comparing the attitude results of the high-precision INS whose gyro drift is about 0.005（°）/h and the accelerometer bias is better than 10^-3g. The major findings are as follows： the internal precision of the yaw, pitch and roll by the direct method are 0.3°-0.5°, 0.3°-1.0° and 0.5°-1.0° respectively. In contrast, by the LS method these values are 0.1°, 0.2°-0.5° and 0.5°-2.0° respectively. Hence, the internal precision of the yaw is improved by using the LS method. When using the attitude angles of the INS as references, the external precision of the yaw（with the system bias of the yaw removed）, pitch and roll by the direct method are about 0.08°, 0.15° and 0.42° respectively. The results by the LS method are almost the same with those by the direct method, excepting that the system bias of the yaw is smaller.