高精度加速度计分辨率的动态估算方法

高精度定位定向系统和重力测量系统需要高分辨率的加速度计,传统测试方法难以确定高精度加速度计的分辨率。对此,提出了一种使用双轴转台动态估算加速度计分辨率的方法,即匀速旋转调制法。将加速度计安装在双轴转台台面上,待转台调平,台面绕倾斜轴转过一个小角度后锁死,回转轴以一定的角速度旋转调制以对重力加速度分量进行细分,将加速度计的输出采样后进行FFT低通滤波,通过加速度计峰值与谷值处输出变化最大值的分析可以确定加速度计的分辨率。最后,对某型加速度计分辨率进行了实验验证,测试结果表明,当倾斜角度为0.001°,旋转调制角速率为10(°)/s,采样率为32 Hz时,输入的加速度最大变化为9.36×10-8g,加速度计敏感到的加速度变化量为1.05×10-7g。

Dynamic estimation method for resolution of high precision accelerometer

High precision positioning and orientation system and gravity measurement systems require high resolution accelerometer,but it is difficult to determine the resolution of high precision accelerometer by the traditional testing method.In this regard,a dynamic resolution estimation method of using two-axis turntable,that is,a uniform-motion rotating modulation algorithm was presented.That is,the accelerometer was mounted on a two-axis turntable table board,and a small angle lock around inclined shaft of the turntable was set after being leveled.In order to subdivide the acceleration of gravity,the rotary shaft was rotated in a certain angular velocity.The output of accelerometer was sampled,and the data was filtered by the FFT low-pass filter.The resolution of accelerometer may be determined by the output by analyzing the maximum change at the peak and valley value.Finally,the resolution was verified by the experiment for a certain type of accelerometer.And,the experiment results show that the theoretical maximum change of the input acceleration is 9.36×10-8g and the acceleration sensed by accelerometer was 1.05×10-7g when the inclination angle,the angular rate of rotation modulation and sampling frequency were 0.001°,10(°)/s and 32 Hz respectively.