Brief Analysis of the Working Principle of Radar Speed ​​Meter

　　Handheld radar speed guns are mainly used for fixed-point measurement. Generally, when traffic police use radar speed guns to measure speeding vehicles on a road section, the radar speed gun can be fixed on a tripod or held in hand for measurement.

　　Vehicle-mounted radar speedometers are mainly used in patrol measurement or mobile electronic police. At present, they are more commonly used in electronic mobile police. Due to the special requirements of electronic police, the speed radar equipped with electronic police generally requires the lobe of its microwave emission to be as small as possible.

　　In the past, radar speed guns could not determine the direction of the target's movement due to technical limitations. Therefore, when there were cars moving in the same direction and in the opposite direction in the measured area, the radar could not determine which car was measuring the speed. With the development of technology, some new speed radars can determine the direction of the target's movement, thus greatly improving the reliability and credibility of the test.

　　Working principle of radar speed gun:

　　The radar speed gun measures the speed of a moving object through photoelectric microwaves. Its working theory is based on the Doppler principle, that is, when microwave light is irradiated on a moving object, a changing value proportional to the speed of the moving object will be generated, and the magnitude of the change is proportional to the speed of the moving object.

　　The radar's microwaves are emitted in a fan-shaped manner (S1), and the targets in the irradiated area will reflect the microwaves (S2). According to the actual measurement requirements, the radar is divided into two modes: static working mode and dynamic working mode. The so-called static mode: the radar is stationary (not in a moving patrol car) and measures oncoming cars or cars moving away in the same direction.

　　The so-called dynamic mode is when the radar is in motion (usually in a moving patrol car) to measure oncoming cars or cars moving away in the same direction. In dynamic conditions, the test is generally divided into reverse measurement and same-direction measurement. Reverse measurement: the test target is moving in the opposite direction to the patrol car. Same-direction measurement: the test target is moving in the same direction as the patrol car.

　　When we choose different test states, the radar uses different calculation rules. Although the technology has developed, some new speed radars can already determine the direction of the target's movement, thus greatly improving the reliability and credibility of the test. Radar speed measurement itself is not easy to determine the direction of the target's movement.