Research On Key Technologies Of Mass Pedestrain Precision Navigation Based On GNSS/MEMS Sensor

Pedestrian navigation for the masses Because of the complex positioning environment and the requirement for low-cost,easy-to-carry devices,faces many technical difficulties in achieving high-precision continuous navigation and positioning.In complex urban environments,such as urban canyons and shaded avenues,there are a large number of multipath signals and purely reflected signals(Non-Line-of-Sight,NOLS)in GNSS observation data,which is difficult to accurately model and seriously affect GNSS observation quality,which reduces the accuracy of navigation and positioning;Secondly,GNSS is prone to location interruption when fully occluded in the building and under the bridge.In this paper,based on the problems of interruption and low positioning accuracy in the mass pedestrian navigation and positioning,the key technologies related to mass pedestrian navigation based on GNSS and low-precision MEMS sensors are studied.1.The observed data quality of the low-cost navigation receiver U-blox-NEO-M8 T was analyzed.Data acquisition and analysis experiments in three typical urban environments: open environment,urban canyon and shaded area are designed.Multipath and NLOS errors are extracted by static short baseline double residual residuals.multipath and NLOS which impact on pseudorange,carrier phase and Doppler observations are analyzed respectively.the eigenvalues for pseudorange gross error detection and carrier gross error detection are constructed.The quality analysis of the observed data and the eigenvalues of the construction are mainly used for the design of the subsequent gross error detection method.2.Aiming at the problem of large amount of gross error data in the observation of low-cost navigation receivers in urban complex environment,a robust GNSS localization algorithm including pre-gross error detection and post-gross error detection scheme is designed.In order to improve the navigation and positioning accuracy,the pseudorange enhancement information and the carrier phase enhancement information are used to carry out the research of the Real Time Difference(RTD)and the Real Time Kinematic(RTK),and carry out related experiments.The experimental results show that the robust GNSS localization algorithm can achieve continuous and smooth positioning results in complex urban environments,but the positioning interruption will occur in the severe occlusion environment.3.In order to solve the problem of frequent navigation and positioning interruption in severe occlusion environment,this paper designs a Pedestrian Dead Reckoning(PDR)algorithm based on the MEMS sensor built-in smart phone,and uses static heading constraint and accelerometer observation filtering.The method is to constrain the heading angle to avoid divergence,thereby increasing the usable time of the PDR.According to the pedestrian trajectory estimation algorithm designed in this paper,experiments are carried out using MEMS sensors built in different mobile phones.The results show that the constrained PDR algorithm can realize continuous position estimation in a short time.As the calculation time increases,the calculation result will appear Great drift.4.Based on the loose combination method of Strapdown Inertial Navigation System(SINS),a positioning algorithm combining GNSS and PDR is designed.The position information of GNSS is used to correct the sensor bias and attitude of PDR.The position difference between the epochs obtained by the difference is used to correct the heading angle,and realize smooth and continuous navigation positioning in various complex urban environments.5.According to repeated experiments,the GNSS/MEMS sensor positioning scheme with carrier enhancement information has horizontal position accuracy of 1.11 m and an elevation accuracy of 1.31 m.The accuracy of the horizontal position and elevation in a relatively open environment is 0.12 m.The number of points at the submeter level or even the centimeter level is above 80%.The GNSS/MEMS sensor positioning scheme with pseudo-range enhancement information has horizontal position accuracy of 2.20 m and an elevation accuracy of 3.87 m.The points with horizontal position accuracy at the sub-meter level is 50% or more.In a complex urban environment,the positioning results of the two schemes are continuous and uninterrupted.The GNSS/MEMS fusion solution incorporating carrier enhanced information meets the requirements of mass pedestrian precision navigation technology.