Application Implementation Of Magnetic Sensor In Intelligent Transportation System

This dissertation was achieved and based on Shanghai key technology projects, the intelligent transportation systems project. Intelligent Transportation System, depending of information technology to coordinate pedestrians, vehicles, and roads that were closely and harmonious planned, so that could established a large area, full-time role, easy to efficiently operate the traffic management system. With the rapid economic development, China's rapid development in urbanization and motorization life, which gradually caused various questions, for example accidents, environmental pollution deteriorating, so the establishment of domestic and intelligent transportation system is necessary and urgent.At present, intelligent transportation system is mainly making use of video, coil, etc., but there are some drawbacks, through argumentation, we selecting magnetic sensors as a reliable signal source. Studied in this dissertation based on magnetic sensor detection system of parking spaces and vehicle speed system, the purpose is to solve traffic congestion, and help maintain traffic safety, ultimately relieve transport and guide the vehicle transport systems to be intelligent. Based on the project, completed two patents:Parking detection system and Vehicle' speed system which based on magnetic sensor; and two software copyrights was in progress:Multi-serials port synchronous data acquisition platform and Sensor data sample library system. This dissertation mainly studies the following several aspects of content:1. Signal analysis of magnetic sensor. Analysis of the merits which existing implementations of the intelligent transportation, especially for the parking spaces and the speed of vehicle analysis, selecting appropriate sensors and data acquisition circuit. Through the analysis of giant magneto resistance GMR sensors on their characteristics, and the axis magnetic signal of the sensors X, Y, Z in the actual situation, finally to complete the application through the system selected focus signal of each axis.By comparison of extracting the signals which from the amplifier circuit at all levels, to determine the source of data used in algorithms, combined with the circuit to adjust the algorithms.2. Algorithms for determining the parking of vehicles. Planned the test program for signals, according to the actual situation to test vehicles in the aisle, into the garage, put right the vehicle, stop in parking, et and other process signals;And in these cases, whether the vehicles near the garage, the difference in signals. According to the signal waveforms and features to set the value of the signal background, used of software to collect the initial background, and used double buffer technology to achieve the background value correction by the amount of the characteristic signal and the processing algorithm to determine whether there is car parking information, and upload the parking information.3. Vehicles speed determination algorithm. Planned the test program for the vehicles speed, according to the reality in the carriageway which looted the sensor device, aiming at the impact of different distances between the sensors, different vehicles'speed, that whether the impact of the direction of the vehicles in areas through data collection and analysis. Finally selected the trial algorithm, tested error compensation was added to complete the vehicles detection algorithm, and upload speed information by the program.The target of the intelligent transportation is to establish a good platform for traffic information communication, for example the parking spaces and the speed system needs a good cross-platform, so this interactive design software was implemented in a record store for the acquired signals, multi-threaded decomposed signals, the amount of extract useful features embed into the algorithms, finally the determined information in the user interface was showed the exteriorized results of monitoring staff and facilitated users'observation. This system is stable, easy to operate, was used in Pudong and Jiaxing, and this study is conducive to the development of the intelligent transportation.