On The Performance Of MEMS Gyro Used In Integrated Vehicle Navigation System

Accompanying with economy development and technology progress, GPS/DR integrated vehicle navigation system becomes more and more used. As a low cost element, MEMS gyro can improve the economical efficiency of integrated vehicle navigation system obviously. The performance of gyro has important effect to navigation system accuracy, so this thesis studies the characteristic of MEMS gyro.Firstly, the circuit and firmware of sampling module are designed based on rationally chosen of A/D converter, and the performance of sampling module is tested in whole measuring range. Result of testing shows that the sampling module can meat the precision requirement of GPS/DR integrated vehicle navigation system. Then, the performance curve of A/D transform circuit is fitted depending on testing data.Secondly, using one freedom rotating floor, the MEMS gyro is tested and the output of gyro is sampled in different speeds. The majority of high-frequency noises are filtered by digital Butterworth filter. According to the method of least squares and multinomial fitting, the curve of gyro is determined and the model of MEMS gyro output is generalized, which considers static drift and first order drift.Finally, based on large numbers of actual measurement data, the statistics feature of gyro drift is verified, and gyro drift is treated as colored noise. The autoregressive model is established by method of time series analysis and the model order number is determined according to criterions such as FPE and AIC. Then, the gyro drift is processed by Kalman filter, and the result verifies that the model is effective.