What is the working principle of the traffic police fixed-point speed measuring electronic eye? How to measure overspeed?

The principle of lateral measurement is that the vertical points of vehicles, radars and radars form a right triangle with the lane when driving. When the radar emits radar waves, it can calculate the length of the hypotenuse of the right triangle between the radar and the vehicle when it meets the reflection of the vehicle body. The distance between the radar and the driveway is known in advance.

According to Pythagorean theorem, we can calculate the distance from the vehicle to the vertical point, that is, the length of the other right-angled side. According to the radar waves emitted twice, the radar can calculate how long the vehicle has traveled between two time points (just subtract the right-angle side length measured twice). Divide this distance by the time interval and you will get the speed of the vehicle.

The principle of the straight-ahead test is: launch radar waves twice, locate the vehicle position at two time points according to the echo, subtract the two position coordinates to get how long the vehicle has traveled during the two radar wave launch times, and divide this distance by the radar wave launch time interval to get the vehicle speed.

When the speed radar finds a vehicle speeding, it will immediately start the camera program, take high-precision photos of the vehicle suspected of speeding, and record the driver characteristics of the vehicle license plate. The traffic police will immediately inform the inspection police waiting in front to intercept and inspect the suspected vehicle, and at the same time transmit the evidence of speeding of the suspected vehicle to the inspection point.

Extended data:

Interval speed measurement is to arrange two adjacent monitoring points on the same road section. The principle is to calculate the average speed of the vehicle in this section according to the time before and after the vehicle passes through the two monitoring points, and judge whether the vehicle is speeding according to the speed limit standard of this section.

Fixed-point speed measurement:

In fact, it is to record the instantaneous speed of passing vehicles at a certain place and play a warning role for drivers passing through this place. But now many drivers will choose to install electronic dogs in their cars to detect the speed measuring equipment in front, and when they are approaching the speed measuring point, they will choose to step on the brakes to avoid the snapshot of the equipment.

Although this can avoid the fear of electronic equipment, there are great security risks, which may make the car owners behind unable to brake catch up with the vehicles in front. Some drivers and friends will drive too fast at a speed of 120KM/ h after passing the speed measuring point, which will not regulate safe driving.

The speed measurement effect of fixed-point speed measurement is not particularly ideal, so there is interval speed measurement again

Interval speed measurement is another speed measurement equipment invested by the traffic police department. The principle of this speed measurement is to set two adjacent speed measuring points on a road section, and calculate the average speed of vehicles passing through the road section by recording the time of vehicles passing through the road section. This speed measuring method is more scientific and fair.

For example, in the section with speed limit 120KM/ h, it takes 30 minutes for a car to pass through a 60km section, so the average speed of a car passing through this section is 120KM/ h ... If it takes less than 30 minutes, the car will exceed the speed limit and will be punished later. Even if you change lanes halfway, the system will automatically identify the snapshot.

Fixed-point speed measurement includes constant speed measurement and velocity measurement:

1 Fixed speed measurement means that the traffic police department sets up speed measuring instruments in some places that need to be monitored to monitor and capture speeding vehicles.

Mobile speed measurement means that the traffic police department sets up mobile speed measurement instruments in some temporary locations that need to be monitored, and the specific locations are unknown.

It should be noted that these two speed measurement methods are mixed in some sections, and there is no overspeed in interval speed measurement, but there may be fixed-point overspeed. So don't take chances.

References:

Baidu encyclopedia-interval speed measurement