Research On Rotating Multimode GNSS Short Baseline Dual Antenna Tight Integrated Navigation Algorithm

Navigation runs through the development of science and technology,and is widely used in the fields of navigation and orientation,drone technology,and car driving.The limitations of a single navigation system have been difficult to meet the requirements of military and civilian fields for positioning accuracy and real-time performance,while the integrated navigation technology has overcome the shortcomings of a single system.The combination of GNSS(Global Satellite Navigation System)/SINS(Strapdown Inertial Navigation System)is more common.This article proposes a MEMS-IMU micro-inertial integrated navigation system that combines GNSS with MIMU and uses a carrier phase double-difference model,The initial orientation of the system is performed by rotating the dual-antenna baseline,and the ambiguity of the whole cycle of the carrier phase is not required.This paper mainly studies the algorithm of the rotating GNSS short-baseline integrated navigation system.According to the different combinations of single-mode tight combination,dual-mode tight combination and carrier phase double-difference and single-difference models,the navigation results of the algorithm for the system are discussed and analyzed..The main research contents and results are as follows:The Kalman filter of the rotating GPS short-baseline dual-antenna tight integrated navigation algorithm is designed,and the parameter error model of the navigation system is established as the state vector of the filter,and the pseudorange and pseudorange rate difference calculated by the GPS system and MIMU are calculated.The difference of the carrier phase double difference is input into the Kalman filter as the observation,and the navigation result of the carrier is finally output by estimating the state quantity and feeding back the system.Through the calculation of the experimental data,it is verified that the algorithm can correctly output the speed and position information of the carrier.The pitch and roll angle errors are better than 0.1°,and the heading angle is better than 1°.Designed a rotating multi-mode GNSS dual-antenna tight combination algorithm,adding the GNSS satellite vector information error as the Kalman filter vector,using the pseudorange,pseudorange rate,and the difference of the carrier phase difference from the GPS and BDS systems as the Kalman Observation of the filter,the filter outputs the solved navigation information after the optimal estimation of the system parameters.The calculation results of the experimental data show that the pitch and roll angle errors of the rotating GNSS multi-mode dual-antenna tight integrated navigation algorithm are better than 0.05°,and the heading error is better than 0.8°.The system accuracy of this algorithm is better than that of the single-mode tight combination.algorithm.The single difference of carrier phase is designed as the observation of Kalman filter to reduce the dependence of the system on the number of observable satellites.By using the single-difference information of the carrier phase of a single satellite into the Kalman filter,the solution results show that the elevation and azimuth angles of the observation satellites in the corresponding range will be more conducive to improving the orientation accuracy of the system.In addition,an experiment with varying the length of the baseline was performed on the system,and the conclusion is that the longer the baseline,the higher the orientation accuracy.The rotating GNSS dual-antenna tight combination algorithm designed in this paper can enable the integrated navigation system proposed in this paper to perform normal positioning and orientation calculations,and optimize the accuracy of the system.