基于椭球假设的三轴加速度计无依托校准方法  

A Triaxial Accelerometer Calibration Method Based on Ellipsoid Hypothesis

作　　者：刘仁浩[1] 王华[1] 夏金秀 

机构地区：[1]北京航空航天大学宇航学院,北京100191 [2]航天科工系统仿真科技(北京)有限公司,北京100076

出　　处：《纳米技术与精密工程》2012年第6期520-524,共5页Nanotechnology and Precision Engineering

基　　金：航天科技创新基金资助项目(CASC0105)

摘　　要：针对现有航姿测量系统三轴加速度计校准方法成本高、精度低以及现场校准能力不足的问题,本文提出了一种基于椭球假设的无依托现场校准方法.首先,根据传感器的灵敏度、偏置以及非正交耦合因素对加速度计的影响,建立了误差椭球校准模型.该模型将三轴加速度计的校准过程转化为将椭球面还原成圆球面的几何变换过程,使得校准参数由15个减少到9个,同时克服了部分非正交耦合参数难以辨识的问题.其次,构造了变权值似然目标函数,根据加速度计测量值的方差调整权值大小,从而降低了测量噪声对校准结果的影响.最后,运用粒子群优化(PSO)算法求解几何变换参数的最大似然估计值,并利用椭球校准模型对三轴加速度计进行校准.实验结果表明,采用椭球假设无依托现场校准方法不依赖外部辅助姿态信息,可在现场将航姿测量系统的倾角误差降低为校准前的1/5,满足了航姿系统的使用需求.To overcome the problems of high cost, low accuracy and insufficient on-site calibration ability from the existing triaxial accelerometer calibration methods for attitude heading reference system （AHRS）, a new method based on ellipsoid hypothesis was proposed for on-site use. Firstly, according to the effect of the sensitivity, bias and non-orthogonal interference on the output of accelerometers, an ellipsoid model for triaxial accelerometer calibration was established, which converts the calibration process of triaxial accelerometer to geometric transformation process from ellipsoid to sphere. Based on the model, the number of calibration parameters was reduced from 15 to 9, and the problem of identifying some non-orthogonal parameters was solved. Secondly, the likelihood estimation objective function with variable weights was established. According to the errors of each aecelerometer＇s measuring data, the corresponding weights were assigned to these error values, i.e. minor weights were assigned to the measuring data with major error, thus to weaken the effects of sensor noise. Finally, the maximum likelihood estimation calibration parameters were calculated through particle swarm optimization （PSO） algorithm, and the calibration method was used to calibrate the triaxial aecelerometer of an AHRS. Experimental results show that the roll angle error is 5 times lower than the one before calibration using the proposed method without auxiliary equipment, which can satisfy the requirement of the AHRS.

关 键 词：加速度计 校准 椭球模型 参数优化 

分 类 号：TH824.4[机械工程—仪器科学与技术]