The Vehicle GNSS/INS Integrated Navigation Under Dual-antenna Constraints

The society's demand for navigation and positioning is constantly increasing.However,single GNSS positioning can no longer meet the needs of people's daily life due to its limitations.The use of multi-sensor fusion to improve the continuity and reliability of the navigation and positioning system has been widely studied and applied.This paper studies the GNSS/INS integrated navigation in multi-sensor fusion positioning.Starting from the constraints between multiple sensors,a method is proposed to improve the positioning accuracy of the integrated navigation system by considering these constraints.This paper includes the following main aspects:(1)The pseudo-range single-point positioning under the constraint of dual-antenna is studied.Based on the GNSS pseudo-range observation equation and constraint conditions,a pseudo-range single-point positioning function model under dual-antenna distance constraints is constructed.Experiments with measured data prove that the model can effectively suppress gross observations and reduce its impact on the accuracy of the navigation system;(2)The combined mode of GNSS/INS integrated navigation is studied.Based on the GNSS pseudo-range,pseudo-range rate observation equation and INS error equation,the mathematical models of GNSS/INS loose integrated navigation and tight integrated navigation are constructed respectively,and the accuracies of loose integrated navigation and tight integrated navigation are compared with measured data.Analysis shows that the accuracy of the tight combination is slightly higher than that of the loose combination.When the number of GNSS visible satellites is less than4,the GNSS/INS tight combination integrated navigation system can still continue to provide navigation and positioning parameters;(3)The vehicle GNSS/INS tight integrated navigation under the constraints of dual-antenna is studied.The extremum function of GNSS and IMU combined with constraints is constructed,and the Kalman filter based on the extremum function is deduced.Experiments have proved that imposing distance constraints on the dual antennas in the GNSS/INS tight combination can improve the accuracy of integrated navigation and suppress gross errors in the navigation system;(4)Aiming at the problem of observation abnormality,based on the GNSS/INS constrained tight combination model,the robust equivalent weight function model is used to suppress the influence of the observation gross error on the state parameters of the integrated navigation system.Experiments show that this method can effectively suppress the influence of gross errors in observations and improve the estimation accuracy of the state parameters of the integrated navigation system.