Speeding has become the primary killer of traffic accidents, especially on fast roads such as highways. Traffic accidents caused by speeding are more frequent. Therefore, the purpose of installing a speedometer is to effectively reduce traffic accidents caused by speeding. ( Now it has been widely used in police speeding tests and other industries. )
1. Conceptual understanding of smart traffic wide-area radar speedometer
1. What is radar speed measurement?
Principle: Velocity radar mainly uses the Doppler Effect. When the target approaches the radar antenna, the reflected signal frequency will be higher than the transmitter frequency; conversely, when the target moves away from the antenna, the reflected signal frequency will be lower than Transmitter rate. In this way, the relative speed between the target and the radar can be calculated by changing the frequency value.
2. Understanding of wide-area radar speed measurement in smart transportation network
① Detection technology is divided into three categories: point, surface, and net.
"Point" is the traditional method of coil and geomagnetism, mainly to realize point data collection;
"Surface" is mainly video and radar technology. These two technologies have developed rapidly in recent years and can realize large-area detection;
"Net" is mainly the trajectory data of sampled vehicles provided by Internet companies. This data provides better support for traffic macro decision-making.
②Expansion : The development of traffic radar technology can be divided into three main stages.
The first is a pure speed measurement technology, which uses the Doppler principle to achieve target speed detection, but the detection accuracy for low-speed targets is low.
The second is speed measurement + ranging technology. A typical application is bayonet trigger radar, which provides data trigger signals within a specified range.
The third is speed measurement + range measurement + angle measurement (wide-area radar), which incorporates the concept of angle to accurately determine the real-time position and real-time speed of each target.
Two, radar speedometer
Radar speedometers on general roads are divided into two types: fixed speed measurement and mobile speed measurement. Fixed speed measurement is divided into fixed-point radar speed measurement and interval speed measurement. The fixed speed measurement, as the name implies, is the method of fixed-point speed measurement by installing a speedometer at a designated point. Different from the flexibility of mobile speed measurement, the mobile speedometer can perform flexible speed measurement in different locations on the same road or on different roads. Generally, mobile speed measurement is usually carried out by police car patrol.
(1) Freeway crossbar top-mounted type
By placing the speedometer on the gantry or other crossbars, by placing the speedometer and the ground at a certain angle (the angle between the speedometer and the road surface should not exceed 30 degrees).
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(2) Mobile speedometer
Install the radar speedometer on the traffic police patrol car or install it on a tripod and place it on both sides of the road for step-on-point speed measurement.
3. Recommended solution: Feiling Embedded FET335XS core board
FET335XS core board ARM Cortex- A8 architecture, operating frequency 800MHz. All components of the core board are of industrial grade, and the whole board has an operating temperature of -40°C to +85°C, and has passed strict high and low temperature tests.
Wide-area radar module Smartmicro radar: monitors road surface information and only outputs vehicle data. The industry mainly monitors traffic incident analysis and requires a radar data processing unit.
Recommended reason
Module interface: network port, 485 serial port
System: linux system;
Main frequency: 800MHz-1GHz
Wide temperature range: industrial grade
Native network port: 2 channels, 1 channel connected to the background server, 1 channel connected to the wide area radar module
Serial port: 1-4 channels ranging, 485, wide area radar module
Customer requirements: 2 Gigabit Ethernet ports, stamp hole
Application scenario: Expressway gantry
Business: Realize the analysis and processing of radar data , monitor traffic incidents, upload the central server, and assist the traffic control department to monitor vehicle information.