速率偏频激光捷联惯组加速度计分析

Analysis and Study on the Accelerometer of Rate-bias Laser Inertial Measurement Unit

速率偏频激光捷联惯组的定向精度除与激光陀螺仪有关外,还与加速度计有关,因此,研究加速度计的指标体系对提高整个速率偏频激光捷联惯组的性能和精度有重要意义。从初始对准和航向保持两个方面研究了加速度计对定向精度的影响:加速度计零偏误差和随机游走均会导致初始对准航向角误差。为了得到高精度的航向保持精度,速率偏频激光惯组的3个加速度计的漂移趋势需要保持一致。试验结果表明,加速度计的零偏稳定性提高4倍,初始对准航向角统计精度提高30%;加速度计精度相同情况下,加速度计漂移趋势一致的速率偏频激光捷联惯组,相比其漂移趋势不一致的速率偏频激光捷联惯组,航向保持精度提高了57%。

The directional accuracy of the rate-bias laser inertial measurement unit(IMU)is not only related to the laser gyroscope but also has a great relationship with the accelerometer.Therefore,the study of the index system of accelerometer is of great significance to improve the performance and accuracy of the rate-bias laser IMU.This paper analyzes the influence of accelerometer on directional accuracy from the initial alignment and direction hold.The zero deviation error and random walk of accelerometers will lead to the error of initial alignment heading angle.In order to obtain high precision heading keeping accuracy,the drift trend of the three accelerometers needs to be consistent.The experimental results show that the bias stability of the accelerometer is increased by 4 times,and the statistical accuracy of the initial alignment heading angle is improved by 30%.Under the same accuracy of accelerometer,the heading keeping accuracy of the rate-bias laser IMU with the same accelerometer drift trend have a 57%improvement than that of the rate-bias laser IMU with the inconsistent accelerometer drift trend.