The Research And System Implementation Of Traffic Accident Scene Investigation Using Differential GPS

Traffic accident scene investigation plays a very important role in traffic accidentprocessing. In order to recover the transportation as soon as possible and provideaccurate and objective data to the followed processing, it is required that the sceneinvestigation should be expeditious, objective and comprehensive. Consequently, it issignificant to study the techniques and methods of rapid traffic scene investigation andaccurate scene mapping which will facilitate the traffic safety greatly.This paper analyzes the existing accident scene investigation techniques. For thecontradiction between speed and accuracy exists in current accident scene investigationprocess, this paper mainly studies the feasibility of differential GPS used as a new toolin traffic scene investigation as well as its application environment. Considering thecurrent working habits of traffic policemen, this paper proposes two modes of usingdifferential GPS for scene investigation. And the corresponding surveying softwarebased on these two modes is developed respectively.Firstly, by comparative analysis, we inspect the related literatures on trafficaccident scene investigation and differential GPS application. Based on severalexperiments, the speed,“ranging” accuracy of differential GPS is measured, and itsportability is also discussed. The result reveals that differential GPS could be a newefficient tool for accident scene investigation. We propose a method of visible satellitescalculation base on a simplified sphere area model. Through modeling of accident sceneenvironment, we estimate the number of visible satellite of differential GPS rover underdifferent conditions, and the applicable conditions of differential GPS for sceneinvestigation is introduced accordingly.Secondly, we design and implement two differential GPS-based traffic accidentscene investigation solutions, which integrated related hardware and software as well asthe corresponding operation and processing modes. Mode1is composed of aninvestigation vehicle, a set of differential GPS device and scene mapping softwareinstalled on tablet PC. Its key features are mapping software-centric, and the data isgathered with the differential GPS based on mapping needs, and transferred with theBluetooth. Mode2is composed of an investigation vehicle, a set of differential GPSdevice, a photographic equipment, portable computer and scene mapping software. It is characterized by differential GPS surveying for positioning data and image recordingfor scene element attributes. Because of the independence of surveying and mappingfunctions and operatiions, mode2reduces time of scene blockade effectively.Furthermore, supplementary measurement of missing scene elements can be supportedon certain conditions.Finally, we prospect the applicaion of differential GPS in whole traffic accidentinvestigation field, analysis the potential problems, and also point out goals of futureresearches.