Many drivers have the experience of running a red light or speeding by an electronic eye and being punished. As long as the electronic eye is photographed, the fine is not 200 or 500, and after the heart pain, many of the driver's friends are looking for equipment for obtaining electronic eye signals. This paper makes a shallow principle analysis and functional comparison of several kinds of common equipment at present. Traffic accidents can be caused by red or overspeed driving. Please think twice about the driver's friends.
Let's first declare that the radar detector is not an illegal electronic product, it simply receives radar waves sent by radar speedometer, so as to remind drivers to pay attention to speed. Moreover, because the product does not send out radar waves or signals to the outside world, it does not violate our country's radio management regulations. This product is completely legal.
1、General radar detector
Let's first talk about the principle of radar velocity measurement. The radar tachometer is based on the calculation of the frequency shift of the reflected waves received and the velocity of the object being measured. The radar beam has a large surface, so the radar speed is easy to capture and need not be accurately aimed. Radar equipment can not only be fixed on the road, can also be installed in the patrol car, realize the detection speed in motion, "is a very important part of the flow of electronic police; secondly, the error of radar fixed speed is + 1Km/h, motion measurement error is about 2Km/h, fully meet the traffic violation investigation based on the international requirements; radar also has 20 years of history, mature technology and low cost. From the present situation, the urban road in Beijing is mainly on the back velocity measurement, but there are also a small number of forward velocity radar tachometer. There are many positive speed measuring devices on the freeway. The back is the radar wave and the direction of the camera and the direction of the car. When the vehicle is overspeed, the camera takes the rear license plate of the vehicle. The forward is the opposite of the radar wave and the direction of the camera and the direction of the car, when the vehicle is overspeed, the camera takes the vehicle's front license plate. The principle of the radar detector is very simple, that is, after receiving the radar signal, it immediately alerts the car, prompting the car owner to slow down.
Most of the radar detectors are imported, and the price is generally from 800 to 5000 yuan, and the performance is very different. The biggest difference is that the frequency of the radar waves that can be induced is different. Because the radar speed measuring devices of various cities in China are imported from different countries, and the radar frequencies used by our country are different. The same city has installed three or four radars with different frequency bands. The low end radar detector can only induce one frequency band of radar wave, while the high-end radar detector can induce radar waves of many frequency bands, and even laser sensors, and also can prevent laser velocimeter.
In addition, the distance and distance of the induction also reflects the performance of the radar detector. If the distance of induction is too close, the car owner is too late to decelerate and has been taken. If the deceleration is too strong, it is easy to cause the rear end accident. High end radar detectors are capable of perceiving radar waves about a kilometre, and the difference is only about 200 meters.
2、Radar detector
The first thing I want to tell you about the electronic dog is that it is an illegal device. Because it does not receive signals but sends signals, it is a violation of our country's radio regulation. The price of the electronic dog is between 250 and 500 yuan. It is very convenient to insert a cigarette lighter when used. It is very simple: the principle of electronic reconnaissance eye dog production of electronic manufacturers, in the electronic eye, stole a radio transmitter, it aims at the route characteristics, transmitting a radio signal containing the information code, the car near here, a radio signal received by the receiver transmitter, decoding alarm type, a sound chip the voice alarm, so the one-way speed, this intersection, the electronic eye.
The advantage of the electronic dog is the low cost. The disadvantages are: first, most of the products are produced in Shenzhen and Shenzhen now almost all the traffic lights are equipped with electronic eye, so the electronic dog will be ringing alarm, not only lose significance, but also very noisy, the general product volume cannot be adjusted, it can not be closed; second, no Commission approval so, the transmitter set is illegal, but also the power supply, to secretly change, may have been removed or damaged. Third, the launching power of the transmitter should be properly set, if it is too small to receive the signal, it is too late; it is too long to begin to call, annoying.
Advantage: cheap
Weakness: illegal, noisy, unreliable, limited.
It is important to note that this product has a lot of sales in Shenzhen. If you are not used locally in Shenzhen, please do not buy it. Because the emitter that can signal this electronic dog is only in the city of Shenzhen, it is completely meaningless to the other place.
3、GPS radar detector
The GPS radar detector can not only make the speed radar alarm, but also make the traffic light electronic eye warning. Whether the monitoring method of the electronic eye is using radar wave, laser or ground induction coil, the GPS radar detector can alarm. Compared with radar detector and electronic dog system, GPS radar detector can identify the direction of the electronic eye, such as the electronic eye in opposite direction or cross direction, and it will not miss the alarm. Just need to pay attention to update the map in the use process, another point is that, if you find out there is not marked on the map, the best according to the "points of interest" will be marked on the map, to remind the day after. In addition, the GPS radar detector can set the alarm advance volume automatically, such as 300 meters or 500 meters. If the vehicle is not speeding, it can not alarm and save trouble. In addition, no matter whether or not the electronic eye, the GPS intelligent dog can remind the owner of the speed limit of the section, is not the speed and so on. In addition to the alarm, the GPS radar detector can also be used in the search for gas stations, toilets, parking lots, and so on. In addition, the general GPS has the functions of navigation, recording and so on.
4、Conclusion
The high end radar detector is almost perfect for the anti reconnaissance performance of the radar tachometer, and can also be used for the velocity measurement point of the mobile radar. The disadvantage is that the price is slightly expensive; and because of the high sensitivity, the rate of misinformation of the radar reflected wave on the other side is high.
Electronic dog illegal, cheap, but to steal a dependent transmitter, the limitations of the larger, more noisy.
The advantage of the GPS radar detector is that it can prevent any way of electronic eyes. Besides, the GPS radar detector has many other uses besides reminding electronic eyes, such as reminder, navigation and so on. The disadvantage is that it needs to update the speed point data regularly, and it is completely ineffective for the velocity measurement point of the mobile radar.
Attention to the use of radar wave detectors:
一、The detector must be placed in the right position to maximize its effectiveness.
1、The detector is fixed on the front windshield glass of the vehicle, or the detector is fixed to the top of the dashboard with a nylon double side glue and receives the antenna toward the direction of the head. The detector should be at the horizontal position or the receiving antenna is slightly upwards.
2、The receiving antenna must block the glass forward and can not be blocked by the wiper, otherwise it will affect the effect of the reception.
二、The car with the front windshield attached to the metal riot insulation film (or with its own anti riot function) will affect the detector's reaction distance
The front windshield with metal riot will be shortened to 2/3 insulation film 1/3 tip distance, the solution is to cut the film riot will receive near the mouth of a block or a whole, or simply not to use riot film, or choose a split type.
三、It is strictly forbidden to use two detectors together
The joint use of two speed measuring devices will cause interference with each other, making the speed meter working unnormal.
四、Urban clutter interference
Urban clutter (such as telecommunications transmission station, high-voltage wire, radio communication device, remote control, automatic door, etc.) will be issued by the microwave frequency detector after similar, when these places, sometimes "false positives" phenomenon, this is normal, can be used to determine whether the false alarm is continuous. Generally speaking, the real wave speed warning sound is continuous alarm, and more recent sources more quickly, and "false positives" is just a two alarm.
At present, the radar speedometer used includes K, Ku, Ka and X. K, Ku, Ka and X are the radar wave bands used for velocity radar, and are also defined by radio frequency. Following a frequency table.
The requirements for the speed of the band X (10.525GHz), K (24.150GHz) two, in addition, most of the European standard microwave production speed product for the Ku segment (13.400 GHz), the products produced in the United States to speed Ka segment (34.700GHz). In China, the above four bands exist at the same time. As far as capital Beijing is concerned, the coverage rate of Ka and K segments is 80%, X and Ku accounts for 20%.
K brand：24.050-24.250GHz