Research On Attitude Determination By Tightly Coupled BDS/MIMU Integration

In recent years,the navigation services play a more and more important role in people's life.And the key of intelligent navigation is to get the location,speed and attitude of user quickly and accurately.In a traditional method,the attitude is mainly measured by the inertial navigation system,but it couldn't maintain high-precision measurement for a long time because of accumulating deviation.As the development of satellite technology,the navigation technology based on Satellite gradually improved.The integrated system of inertial navigation system and satellite navigation system can overcome the accumulating deviation defect of the inertial navigation system,and the highly dependent on external conditions of the satellite system.This paper focuses on analyzing the fundamental theory of attitude determination by BDS system and inertial navigation system respectively,and researching on the deviation model of them.Moreover,it proposes a new filter scheme which employs the high-precision observations for data fusion.Firstly,the basic algorithm model and error model of BDS and inertial attitude measure system are studied.To get a higher precision of the attitude computed from the integrated system,this paper models and calibrates the deviation of gyroscope and accelerometer respectively.Furthermore,it defines the calculation process of BDS system's precision by the accuracy of floating point and fixed solution which provides the basis for the adaptive adjustment of the filter.Secondly,the filter of integrated system was designed with the differential carrier phase and differential pseudorange rate as the main observation.In this paper,we use the double difference carrier phase and double difference pseudo range as the observations of the integrated to get access a high precision of the integrated observations,and to realize the complementary advantages of BDS and MIMU.In addition,in order to improve the accuracy of dynamic measurement from the integrated system,the unscented Kalman filter is designed to improve the performance of nonlinear.Finally,the experimental tests were conducted to verify the performance of the proposed attitude determination algorithm in several different scenarios.An attitude determination verification platform is set up to collect observation data of BDS and INS in static condition,rotation condition and obscured signal condition.Then,the actual data-sets are simulated and the results are compared and analyzed to verify the accuracy,stability and feasibility of the system.Testing results show that the BDS/INS integrated algorithm proposed this paper can provide attitude with high precision,stability and frequency.