1. video surveillance and acquisition technology
The technology is a new acquisition technology that combines video image and pattern recognition into the field of traffic. After the video acquisition system converts the continuous analog images collected by the video acquisition equipment to the discrete digital image, the vehicle number, vehicle and other information are obtained by the software analysis and processing, and then the traffic parameters, such as traffic flow, vehicle speed, head time distance and occupancy rate are calculated. The video detection system with vehicle tracking function can also confirm the steering and lane changing actions of vehicles. The video detector can collect the most traffic parameters, and the collected images can be reused, which can provide visual images for accident management.
Video surveillance has a great advantage over other sensing technologies. They do not need to deploy any equipment on the road or roadbed, so it is also known as "non implantable" traffic monitoring. When a vehicle passes through, the video captured by black and white or color cameras will be entered into the processor to be analyzed to find the changes in the feature of the video. Cameras are usually fixed on buildings or posts near the driveway.
2. GPS Technology
GPS is the core technology of many vehicle internal navigation systems. The embedded GPS receiver equipped in the vehicle can receive signals from different satellites and calculate the position of the vehicle at present. The error of the positioning is usually a few meters. Vehicles need wide vision when receiving GPS signals, so the use of the technology may be restricted due to the shelter of buildings in the central area of the city.
3. special short range communication technology
Dedicated Short- Range Communication (DSRC) technology is a special wireless communication technology designed for communication between vehicles and road infrastructure in the field of intelligent transportation. It is a specification for the communication interface between the vehicle unit (electronic label) fixed on the lane or the road side and the vehicle mounted on the mobile vehicle.
The DSRC communication system mainly consists of 3 parts: On- Board Unit (OBU), roadside unit Road-- Side Unit, RSU and communication protocol. The DSRC technical standard used in our country works in the ISM58GHz band, the downlink is 5.83GHz/584GHz, the transmission rate is 500Kb/s, the uplink is 5.79GHz5.80GHz, and the transmission rate is 250Kb/s.
DSRC technology connects the vehicle and the road infrastructure into a network through two-way transmission of information. It supports point to point and point to multi point communication. It has the characteristics of two-way, high-speed, real-time and so on. It is widely used in the fields of road toll, vehicle accident warning vehicle travel information service, parking management and so on.
4. position sensing technology
The location sensing technology in intelligent traffic is currently divided into two categories, one based on satellite communication positioning, such as the Global Positioning System (GPS) in the United States and the China's Beidou Positioning System, which use the satellite to transmit the reference signals around the earth, and receive more than 4 satellite signals at the same time, through three The method of angle measurement determines the longitude and latitude of the current position. The road speed and other traffic data can be calculated by recording the receiver in the special vehicle and recording the three-dimensional position coordinates (longitude coordinates, latitude coordinates, altitude coordinates) and time information of the vehicle at a certain time interval, and with the electronic map data.
Another kind of location sensing technology is based on cellular network base station. Its basic principle is to use cellular structure of mobile communication network to obtain corresponding traffic information by locating mobile terminal. The technology includes two methods: the first is to make absolute positioning of the mobile terminal by the known location of the cellular base station, for example, based on the time of arrival, the time difference, and the A-GPS (Assisted GPS) technology to locate the mobile terminal; the second is based on the base station switching behavior, and the mobile terminal will switch to the new base station to ensure the network during the moving process. The quality of the collaterals. Therefore, the movement on the urban road corresponds to a stable switching sequence, and the traffic flow information can be calculated by collecting all the user switching sequences at the base station.
RFID is the abbreviation of RadioFrequencyIdentification, that is radio frequency identification. It automatically identifies target objects and obtains relevant data by radio frequency signals, and it can work without any manual intervention, and can work in all kinds of harsh environments. RFID technology can identify high-speed moving objects and identify multiple labels simultaneously, which is fast and convenient.
The basic RFID system consists of tags (Tag), reader (Reader) and antenna (Antenna). RFID technology has a broad application prospect. Logistics storage, retail, manufacturing, medical and other fields are the potential application fields of RFID. In addition, because of its fast reading and hard to forgery, RFID has adopted the RFID technology RFID with vehicle communication, automatic identification, location and far away. Distance monitoring and other functions are widely used in the recognition and management system of mobile vehicles.