With the expansion of China's urban construction scale and the increasing number of vehicles, the management and reasonable scheduling of transportation, the command and safety management of police vehicles have become an important issue in the public security and transportation system. In the past, the equipment used in the traffic management system was mainly radio communication equipment. The dispatching center announced the dispatching instructions to the vehicle drivers. The drivers could only tell the approximate location of the vehicle according to their own judgment, but they could not confirm their location or even get lost in unfamiliar areas or at night. Therefore, its use is limited from the aspects of dispatching management and security management.

1. General

The presentation of GPS positioning skills provides detailed real-time positioning ability for the navigation and positioning of vehicles, ships and other vehicles. Through the on-board GPS receiver, the driver can know his detailed orientation at any time. After the vehicle radio sends the GPS positioning information to the dispatching command center, the dispatching command center can timely grasp the detailed orientation of each vehicle and display it on the large screen electronic map. At present, the main systems used in public security and transportation are: the command and management system combining vehicle GPS positioning and wireless communication system; Command management system using GPS Differential skills. The working principle and equipment composition of these two management systems are introduced below.

2. Vehicle GPS positioning management system

The vehicle GPS positioning management system is mainly composed of on-board GPS autonomous positioning, combined with wireless communication system to dispatch, manage and track vehicles. It has been successfully developed, such as vehicle global positioning alarm system, police GPS command system, etc. It is used for urban bus dispatching, vehicle and vessel alarm and dispatching in scenic tourism areas, and vehicle and vessel dispatching and monitoring by customs, public security, coastal defense and other departments. The main functions of the monitoring center include:

· data tracking function. The real-time orientation of the moving vehicle is displayed in a list method. Such as vehicle number, longitude, speed, heading, time, date, etc

· stalking function on the figure. The positioning information of the mobile vehicle is displayed on the corresponding electronic ground (SEA) map. The electronic map (SEA) can be expanded, reduced, restored and switched at will. There are two admission methods: normal admission and random roll call admission. It can also provide the selection function of whether to run the track of the vehicle.

· imitate and show function. The known direction information can be input into the computer and displayed. Decision command function. Decision command commands communicate with mobile vehicles by means of communication. The communication method can be text, code or voice to complete the dispatching command.

· the main functions of the on-board part include:

· sending function of positioning information. The GPS receiver locates in real time and sends the positioning information to the monitoring center through the radio station.

· data display function. Display the real-time orientation of its own vehicle on the display unit. Such as longitude, latitude, speed and heading.

· acceptance function of dispatching instructions. Receive the dispatching command command sent by the monitoring center and display or announce the voice on the display unit.

· alarm function. Once an emergency occurs, the driver starts the alarm device, and the monitoring center immediately displays the vehicle situation, accident location, vehicle personnel and other information.

Vehicle GPS positioning belongs to single point dynamic navigation positioning. The positioning accuracy is about 100m. In order to improve positioning accuracy, differential GPS technology can be used.

The article comes from Jiangmen vehicle navigatorhttp://m.leakdamagelaws.com