Research On The Individual Soldier Navigation Technology In Complex Environment Based On MEMS/GPS Integration

In the initial stage of the development of individual soldier navigation,GPS is mainly used to realize the individual soldier navigation and positioning function.However,due to the wide range of activities during individual soldier combat,such as indoors,urban centers and dense forests,the GPS signals are severely obscured.Therefore,only using GPS can not meet the needs of individual soldier navigation.In recent years,the rapid development of MEMS technology in all aspects has added new vitality to the individual soldier navigation system.This paper uses MEMS as the main research object of the individual soldier navigation system.According to the difference of the number of visible stars detected by the GPS receiver,the individual soldier activity range is divided into indoor and outdoor parts.Different navigation and positioning methods are used for individual soldier navigation in indoor and outdoor environmentsThe problem that the GPS signal is completely obscured indoors,this paper designs a foot-mounted individual soldier navigation system based on zero velocity update method.The foot-mounted individual soldier navigation positioning algorithm includes the following two important problems.The first problem is the zero-speed detection.The second problem is the divergence of the heading error angle due to the unobservable heading error angle.For the first problem,the generalized likelihood ratio method is used to detect the different gaits of individual soldiers.The feasibility of this method is verified by a large number of experiments.For the second problem,this paper proposes zero integrated heading rate update method to suppress the divergence of the heading error angle.This method is inspired by the zero velocity update method.Theoretically,the values of the heading angle calculated by the MEMS strapdown inertial navigation algorithm should be the same at two adjacent sampling points in the stationary phase.However,due to the large drift error of the MEMS micro-inertial component,the values of the heading angle are different.Therefore,the difference between the heading angles is taken as measured value to suppress the divergence of the heading error angle.A large number of experiments have verified that the positioning accuracy of the foot-mounted individual soldier navigation system can be greatly improved after applying the zero integrated heading rate update method.Due to the variety of outdoor environments,the number of visible stars detected by GPS receivers is often less than 4.Therefore,the MEMS/GPS loose integration system cannot be used normally.In this paper,the MEMS/GPS tight integration system using the pseudorange are less than 4,the simulation analysis of the MEMS/GPS tight combination system reveals that the MEMS/GPS tight combination system can maintain the navigation parameter error within a certain range in a short time.But as time goes by,the navigation parameter error cannot be suppressed.This results in a large deviation between calculated position and real position.In order to solve the above problems,this paper uses the "pseudo observation" method to increase the number of visible stars by using the earth as a "pseudo-satellite".This method has been added one-dimensional observation information to the original measurement equation.The simulation proves that this method can suppress the divergence of navigation parameters when the visible stars are less than 4.