Application of Internet of Things Technology in Intelligent Transportation: GPS Technology
GPS is the core technology of many in-vehicle navigation systems. The embedded GPS receiver equipped in the vehicle can receive signals from different satellites and calculate the current location of the vehicle. The positioning error is usually a few meters.
Vehicles need to have a wide field of view when receiving GPS signals, so the use of this technology may be limited in the central area of the city due to occlusion of the building.
Application of Internet of Things Technology in Intelligent Transportation ú║Dedicated Short Range Communication Technology
Dedicated Short-Range Communication (DSRC) is a dedicated wireless communication technology designed for communication between vehicles and road infrastructure in the field of intelligent transportation. It is fixed to the lane or roadside unit and loaded on the moving vehicle. Specification of the communication interface between the vehicle unit (electronic tag).
The DSRC communication system mainly consists of three parts: On-Board Unit (OBU), Road--Side Unit (RSU) and communication protocol. The DSRC technical standard adopted in China works in the ISM58GHz frequency band, with a downlink of 5.83GHz/584GHz, a transmission rate of 500Kb/s, an uplink of 5.79GHz and 5.80GHz, and a transmission rate of 250Kb/s.
DSRC technology connects vehicles and road infrastructure into a network through two-way transmission of information, supports point-to-point and point-to-multipoint communication, and has the characteristics of two-way, high-speed, real-time and strong, and is widely used in road toll and vehicle accident warning vehicles. Travel information service, parking lot management, etc.
Application of Internet of Things Technology in Intelligent Transportationú║: Location Awareness Technology
Location-aware technologies in intelligent transportation are currently divided into two categories, one based on satellite communication positioning, such as the US Global Positioning System (GPS) and China's Beidou positioning system, which use satellite launch benchmarks orbiting the Earth. Signal, the receiver receives more than 4 satellite signals at the same time, and determines the latitude and longitude of the current position by triangulation.
By deploying the receiver on a special vehicle and recording the three-dimensional position coordinates (longitude coordinate, latitude coordinate, height coordinate) and time information of the vehicle at a certain time interval, supplemented by electronic map data, road speed can be calculated. Traffic data.
Another type of location-aware technology is based on a cellular network base station. The basic principle is to utilize the cellular structure of the mobile communication network to obtain corresponding traffic information by locating the mobile terminal.