利用Butterworth滤波器平滑加速度计的双天线GNSS/MEMS组合测姿

Dual Antenna GNSS/MEMS Integration Attitude Determination with Butterworth Filter Smoothed Accelerometer

在双天线GNSS/MEMS组合测姿中,低精度、低成本的MEMS加速度计输出通常包含比较大的噪声,导致由加速度计调平计算得到的水平角观测值精度较低,影响组合测姿的精度和可靠性。不同于传统的时域降噪方法,从频域的角度出发,根据实际车载运动中加速度计输出具有因汽车固有结构产生的高频振动噪声的特点,利用滑动窗口的Butterworth低通滤波器平滑加速度计输出。动态车载实验结果表明,该滤波器降噪效果明显。与滤波前相比,水平角观测值精度提升了约4倍,达到(0.643°,0.546°)。在此基础上,滤波后组合测姿精度也从(0.124°,0.738°,0.532°)提升到(0.122°,0.074°,0.052°),其中水平角精度提升了大约一个数量级,滤波后的测姿结果更加准确可靠。

In the dual-antenna GNSS/MEMS integration attitude determination,MEMS accelerometer,with its low precision and low cost,usually contains relatively large noise,which results in low accuracy of accelerometers derived horizontal angles and impacts the accuracy and reliability of attitude determination.The accelerometer signal has high-frequency vibration noise caused by the inherent structure of the vehicle.Therefore,instead of the traditional time-domain denoising methods,the Butterworth low pass filter with sliding window based on frequency domain method is designed to smooth accelerometer in this paper.A vehicular test result shows that the filter has a better effect on denoising and the accuracy of accelerometers derived horizontal angles is improved by about four times,reaching(0.643°,0.546°).Additionally,the integration attitude solution is also improved from(0.124°,0.738°,0.532°)to(0.122°,0.074°,0.052°),where horizontal angles accuracy has an improvement about one order of magnitude.It is verified that the attitude solution after Butterworth low pass filtering is more accurate and reliable.