Application of wireless geomagnetic vehicle detector in Intelligent Transportation

Common detector of signal control system

Inductive loop detection device

Video detection device

Micro wave detection device

Inductive loop detection device problems

Long time needed for road installation

• When the distance from Inductive loop detection device to signal is relatively long, repeater needs to be added

• Short service life, due to vehicle rolling and pavement deformation, resulting in coil broken, need repeated constructions

• Ferromagnetic materials under the road will cause the decline of detection accuracy (such as bridges)

Video detection device Problems

• High construction cost

A、Need setting pole, braiding, pipeline construction

B、Professional debugging

C、Installation with stacker

• Poor data accuracy

A、Rain, snow, fog and other weather conditions

B、The influence of light on the detection accuracy of occupancy time is low, and has great influence on some signal control systems (such as scats)

• High maintenance cost

A、Due to the impact of wind and vehicle on the rod, caused the lens displacement, which reduces the detection accuracy and requires manual maintenance

B、The lens needs to be cleaned regularly

Micro wave detection device problems

• High construction cost

A、Need setting pole, braiding, pipeline construction

B、Professional debugging

C、Installation with stacker

• Data accuracy is poor

A、Mutual occlusion of vehicles

B、The detection accuracy of low speed vehicles is poor

C、Ferromagnetic objects in the environment cause abnormal echo, resulting in poor detection accuracy

• Due to the impact of wind and vehicle hit on the rod, caused the equipment displacement, which needs manual maintenance

Working principle of traffic vehicle detector

At a certain point on the earth, the intensity of the earth's magnetic field is basically constant for a period of time. When a vehicle passes by, it will form a continuous disturbance to the intensity of the magnetic field. The motion information of the vehicle can be obtained by calculating the disturbance.

Comparison with other detectors·

Wireless geomagnetic vehicle detector has the highest similarity with Inductive loop detection device. Coil is the most widely used and the earliest Technology (most of the research and development of signal system are based on coil), so it has the strongest substitution for coil.

Data types that can be detected

Flow

Occupancy time

Headway

Speed

Data types that can be calculated

Vehicle spacing

Saturation

Vehicle length

System structure of wireless geomagnetic vehicle detector

• Wireless vehicle detector

• Receiver

• Acquisition center

• Software platform

Functions of the wireless geomagnetic vehicle inspector are as follows:

• Small volume;

• Easy to install, no power line, no data line, no application for breaking the circuit;

• Ultra low power consumption, can work continuously for 5 years;

• Lithium sub battery is used, stable high working voltage, high discharge voltage, low self discharge rate (stored at 25 ℃ for 1 year, lower than 1%), and the working temperature range is - 40 ℃ ～ + 85 ℃;

• Communication distance is long, and it can reach 300 meters from the junction or road section acquisition center equipment;

• Whether the vehicle is running at high speed, or moving slowly or even stationary, it can be detected;

• Strong anti-interference ability, strong adaptability, not affected by the environment;

• Generally, there is no maintenance in the case of no road repairment;

• The annual average cost is very low due to the long duration of continuous use

Function of Receiver

Using 2.4GHz wireless communication technology and the existing short-range communication protocol. Its main function is to extend the communication distance between intersection or control center equipment and geomagnetic vehicle detector, and also to increase the capacity of short distance wireless network terminal (geomagnetic vehicle detector). Each receiver allows up to 16 geomagnetic vehicle detectors to join the network. The number of geomagnetic vehicle detectors can be increased by increasing the number of receivers. It can use a variety of ways for power supply: direct 110 V ~ 220 V AC power supply, DC power supply, solar power supply. Through configuration, the product can become the communication part of the collection center. Generally, it is more than 130m and works reliably.

• The depth grade is class 5

Functions of data acquisition center

Communication information, communication status information, vehicle detector detection information and status information are displayed on the screen. It includes the operation status, power supply voltage and communication status of the detector.

• Browse the information of vehicle detector. It includes detector type (function), detector position and attribute.

• System time modification.

• The parameters of the detector are modified, including communication parameters, location information, corresponding relationship between vehicle detector and lane, and operation parameters.

• The output mode is various. TTL high effective, TTL low effective, switch normally open, switch normally closed, serial port, 485, 422, network port, etc. The output mode can be customized according to the actual needs.

Functions of software platform

Subarea management;

• Intersection or road section management;

• Vehicle detector installation location information, Lane correspondence, parameter setting;

• Equipment timing of intersection or road section acquisition center;

• Traffic statistics query;

• Vehicle detector status query;

• Query the packet loss rate of vehicle detector in recent 24 hours;

• Vehicle detector fault inquiry;

• Data synchronization between server database and local database

Reduce installation and use costs

The power supply of the geomagnetic vehicle detector uses its own battery, and the communication uses wireless, so as to reduce the installation cost

• The receiver can use on-site power or solar energy, and wireless communication can be used to reduce the cost of setting pole and pipeline construction

• There is no need for on-site professionals to debug the equipment

• There is no need for a professional stacker for debugging and installation

• The software platform can send fault information to maintenance personnel by SMS or e-mail to reduce the cost of inspection