超高灵敏度加速度计温度模型测试方案与实验

Testing scheme and experiment of temperature model for ultra-high sensitivity accelerometer

超高灵敏度加速度计广泛应用于空间探测和地球重力场测量等领域,评估温度对其的影响并将之扣除,对提高加速度计的精度有着重要意义。针对此类加速度计零偏和标度因数的温度模型测试方案,详细分析了测试过程中可能产生的误差项及作用机制,确认了重力场升降温测试中对称位置法依然可以有效消除温度变化相关的安装面变形误差,从而提升了测试精度。基于此分析,利用带温箱的二轴转台进行了小角度倾斜多位置旋转实验,验证了分析的正确性以及方法的有效性。对自研的ng分辨率MEMS加速度计的测试结果表明,零偏的温度系数测试不确定度达0.5μg/℃(95%置信区间),标度因数的温度系数测试不确定度达4 ppm/℃(95%置信区间);此外,对星载试验的实测数据,经地面所测模型补偿后可将温度效应降低至补偿前的3.5%。

Ultra-high sensitivity accelerometers are widely used in the space exploration and measurement of the earth’s gravitational field.It’s of great significance to evaluate and compensate the influence of temperature on them for improving the accuracy of the accelerometers.Analysis of the error terms are revisited in detail for their mechanism of action in the temperature model test of the accelerometer’s bias and scale factor;it is confirmed that the test method based on symmetrical position in the gravity field still applied to partly cancelling out errors due to fixture deformation for various temperatures.The validity of error analysis and the feasibility of the method are verified by the static multipoint angular rotation test on a tilted two-axis turntable with a temperature control system.The test results of home-made nano-g accelerometers show that the uncertainty of the bias sensitivity is 0.5μg/℃(with 95%confidence bounds),and the uncertainty of the scale factor sensitivity is 4 ppm/℃(with 95%confidence bounds).The output drift of the accelerometer is reduced to 3.5%in a space borne test after compensating the temperature effect by the temperature model tested on the ground.