When you drive a vehicle on the road, do you often encounter a coincidence: After the green light is on, it often turns to red after the last vehicle has passed, and the time is very accurate. In fact, this kind of experience is not a "coincidence", thanks to the geomagnetic sensor buried under the road. In conjunction with intelligent traffic lights, in order to further improve the traffic capacity of urban roads, geomagnetic sensors are playing a very important role, allowing traffic lights to "change their faces" with traffic flow.
1. To understand geomagnetic sensors
The geomagnetic field is an inherent resource of the earth, which provides a natural coordinate system for aviation, aerospace, and navigation, and can be used for the positioning and orientation and attitude control of spacecraft or ships. Magnetic navigation technology that uses the spatial distribution of the earth's magnetic field is simple, efficient, reliable, and anti-interference. It is one of the indispensable basic navigation and positioning methods in developed countries. For example, Boeing aircraft with a high degree of automation are equipped with magnetic navigation and positioning systems.
The application of magnetic sensing technology in transportation is geomagnetic sensor. The buried wireless geomagnetic vehicle detection system is used to replace the traditional coil type vehicle detector. When the vehicle passes through the area where the geomagnetic sensors are buried, the passing and passing of the vehicle is judged by detecting the change of the surrounding magnetic field relative to the earth's magnetic field. After the receiver receives the detector signal, it transmits the signal to the corresponding system to complete the vehicle detection.
2. Geomagnetic sensors in traffic
On the road section where the geomagnetic sensor is installed, the vehicles waiting for the red light will be detected by the geomagnetic sensor, and the signal control system will automatically adjust the passage signal duration according to the number of waiting vehicles. When the traffic signal is "distributed on demand" like this, it will greatly shorten the clearance time at the intersection, reduce the waste of traffic resources, and reduce the occurrence of congestion.
At present, the traffic signals in some places have been intelligentized. Many arterial roads will form a "green wave belt" within a certain period of time, and it is precisely because of the detection information provided by the geomagnetic sensor that this "green wave belt" is formed smoothly, which plays a role in dredging and maintaining smoothness. Sometimes the road section is relatively short, and when turning left from a short street, there are not many vehicles waiting to turn. If the left turn signal time is too long, it will affect the traffic on the street. This phenomenon basically does not appear now. The reason is that the geomagnetic sensor "directs" the intelligent signal lights to adjust to the traffic flow.
When vehicles are congested, manual decongestion is carried out by increasing police force; when passing vehicles are not saturated, scientific and technological equipment is used to direct traffic. This artificial and intelligent traffic management method has become more mature. With the use of technological equipment such as geomagnetic sensors and smart signals, the current traffic management has become more perfect and more scientific and reasonable.
