基于比力差分测量的加速度计温度误差补偿方法

Thermal error compensation algorithm for accelerometers based on differential measurement of specific force

针对温度变化引起的惯导系统中石英挠性加速度计测量误差,提出了一种基于比力差分测量的加速度计温度误差补偿方法。首先,建立包含温变速率影响的温度误差模型,利用标定惯导系统加速度计参数时的温度作为标定参数温度基准。其次,借助不带转台的温箱对惯导系统进行全温测试,通过同一方位前后时间段加速度计输出的差分消除未知的比力真值,只保留由于温度改变引起的标度因数与零偏变化,通过多位置观测对这两项参数进行最小二乘拟合估计,获得对应温度系数。该方法不需要温箱具备高精度定位基准,能够实现全温范围与快速变温工作条件下温度误差的精确建模。试验结果表明,应用该补偿方法可使加速度计测量精度在全温范围内保持在10μg量级。

In view of the thermal measurement error of the quartz flexible accelerometers in the inertial navigation system, a thermal error compensation algorithm is proposed for accelerometers based on differential measurement of specific force.A temperature error model is established by taking into account the effect of the temperature＇s varying rate and using the temperature when calibrating the accelerometer parameters as the reference.Thermal experiments are carried out in a climate chamber without turntable, and the accelerometer＇s outputs of the pre and post time segments in the same location is differentiated in order to eliminate the unknown true values of the specific force and preserve the temperature-caused variations of the scale factors and biases.Based on these, the thermal coefficients are obtained by using the least square estimation via multi-position observation.The proposed method does not need the chamber to have high-accuracy positioning reference, and can realize high-accuracy modeling in full temperature range under the working condition with rapid temperature changing.Experiment results illustrate that the proposed method can have the measurement precision of the accelerometers maintain at the level of 10 μg in full temperature range.