Methods Of Improving Calculation Accuracy Of Trajectory In Vehicle-borne LiDAR

Vehicle-borne LiDAR is one of the most advanced technologies in the domain of surveying and mapping at present. It has many advantages to obtain data,just as quick survey speed, high accuracy ,low cost ,obtain data actively and so on. So, it has distinct advantage in the survey of highways,city streets,banks and other reigions.But when it comes to tunnel and tall buildings in urban environments, the GPS signal often outages, and the accuracy will decline.Accuracy decreased hinder the development of the system. This thesis focuses on the measurement accuracy of Vehicle-borne LiDAR system, occurrence of GPS signal outages under different circumstances, accuracy improvement in the tunnel and city. The thesis includes three parts:First, analyzes the error source and the precision of Vehicle-borne LiDAR measurement in the highway system. Obtain GPS signal outages information in urban area and the causal factors in different environments via experiments;Second, uses trajectory control points to improve measurement accuracy of the system when it is through the tunnel;Third, based on the multipath effect and GPS signal outages phenomenon in the city, presents a IMU method, which locates the time slot of GPS signal outages by elevation variation rate, and deleting the GPS location date.The innovations of this thesis mainly lie in the two aspects as follows:(1)Control the data decoding by using the trajectory control points when the system goes through the tunnel. And the measurement accuracy is therefore improved;(2)Put forward to using elevation variation rate to locate the region when the system is influenced by multipath effect in urban, during that time, use the IMU decoding data instead of POS decoding data, so that the accuracy trajectory data processing is enhanced.