| In modern society,the demand for indoor navigation is becoming increasingly strong.Inertial navigation is an ideal technology to realize indoor pedestrian navigation which can complete navigation work independently without the help of GPS signal or external environment.However,the calculation error of single inertial navigation will increase gradually with time,which cannot meet the accuracy requirement in long time working.UWB positioning technology has some outstanding features such as high precision and anti-interference characteristic,but it also has the problem of trajectory discontinuity caused by low sampling frequency.Integrated navigation system can integrate the advantages of different subsystems and make up for the limitations of single approach.In order to overcome the limitation of precision defects on indoor pedestrian navigation,research on combined pedestrian navigation algorithm based on optimal configuration is becoming one of the key research directions.In this paper,the optimal configuration and the combination method for pedestrian navigation system based on micro-inertial measurement unit(MIMU)is studied to meet the requirements of indoor positioning under the condition of satellite signal rejection.Firstly,this paper analyzes the positioning technology such as inertial navigation,and then introduces its positioning principle and characteristics.The cumulative error correcting method and the combination technology based on indoor inertial pedestrian navigation is also discussed.Secondly,for the pedestrian navigation system with MIMU mounted on foot,an inequality constraint error correcting method based on dual-foot MIMU configuration is studied.A pair of micro-inertial elements are placed on both feet to complete the initial error compensation of zero-velocity correction respectively.Then,the walking motion characteristics and the distance limitation between two feet are utilized.The inequality constraint relationship of the dual-MIMU subsystems is summarized and the ellipsoidal constraint model is established.At the same time,the adaptive adjustment of step length constraint is realized by calculating the step size by the characteristic of acceleration.Based on the studies above,the combination model of dual-MIMU subsystem and the head-attached UWB subsystem is designed.This paper uses the idea of loose combination to build integrated model,and completes data fusion process through Kalman Filter.In this way,the positioning information of the two technologies are integrated with each other to achieve complementary advantages.Experimental results and simulation analysis show that the proposed adaptive step length ellipsoid constraint algorithm and the combination of MIMU&UWB subsystems overcomes the problem of discontinuous trajectory in single UWB positioning,and at the same time,further improved the positioning accuracy.This study provides a certain research idea for the optimal configuration of pedestrian navigation system under GPS signal rejecting environment.46 figures,6 tables and 77 references are supplied. |
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