It happens many times in the real life that you are driving with the other traffic around you, in a safe way, but are driving 5, 10 or sometimes 15 km/h faster than the allowed maximum speed. To avoid fines (a point deduction from your license), we use radar detectors.
There are many kinds of equipment in the market. To have a good overview, it is important to diversify the categories of equipment.
GPS equipment is based on American satellites and makes it possible to locate your actual position. The most common consumer application nowadays is a Navigation system. Such navigation systems are also able to route you to Points of Interests, like shopping centers, tank stations, etc.
Another consumer application is a GPS speed Camera Locator. This product has also a list of Points of Interests that contains most of the fixed camera's, dangerous locations and frequently used mobile inspection locations. Once you come in a distance of 500 meters from such location, you will receive a warning.
Those GPS speed camera Locators are also able to warn you if you drive faster than a maximum speed setting.
This kind of equipment is not receiving information from speed camera's, nor disturbing the operation of speed camera's, but is only receiving a database from internet with the actual speed camera information.
Radar Detector Equipment
A widely used technique for speed cameras is the use of Radar. A radar beam is emitted to the road. If a vehicle is passing, then a reflected signal in a slightly modified frequency will be reflected. The difference in frequency is a measure for the speed of the vehicle. In case the vehicle goes too fast, then a photograph is made.
A radar detector is a receiver (like a car radio is a receiver).
A flash camera is a transmitter and a receiver (like a radio station is a transmitter, and has also a receiver).
The radar detector is not disturbing the operation of the flash camera. (Like the car radio is also not disturbing the radio station).
Once the radar detector is receiving some information from a frequency like a flash camera, then the radar detector starts to make an alarm. This will notify the users that he (or she) has to check his (or her) behavior and correct anything that is not OK.
Unfortunately, a lot of automatic doors are working on the same frequency as a Speed Camera, so the radar detector does make false alarms in a city environment.
On the contrary, a RadarJammer is a transmitting device. The RadarJammer does "jam" the flash camera, by sending too much signal to the receiver of the flash camera. This kind of equipment is illegal for all countries.
Laser Detector Equipment
Another technique that is widely used for mobile speed checks by police officers is Laser. The speed check equipment points a laser beam to the license plate of the car. Within a second, a complete measurement is made of the speed of the car. So the speed check equipment is both a transmitter and a receiver for the Laser signal.
The Laser detector is only a receiver. It has the capability of receiving laser light through a lens, like a photo camera. The laser detector is only sensitive for the laser light of 904 nm that is being used by this kind of equipment. Once this laser light is detected, a warning signal will be made to the user. This will notify the user that he has to check his behavior, and correct anything that is not OK.
A Laser Jammer is a transmitter device. It transmits a Laser signal that does 'jam' the speed check equipment, so the police officers cannot make a speed check with their device. This kind of equipment is illegal for most countries.
The Radar detectors do have a combined Laser and Radar detection circuitry. The devices are only receivers, not transmitters. The devices comply with the American(FCC),European rules, and have the CE marking and E-marking for automotive products. The radar detector uses a super heterodyne receiver with scanning frequency discrimination technology and a linear polarization. The Laser detector uses a pulse Laser signal receiver with optimized lenses.
The GPS Locators ,most of them,do have GPS Sirf Star III technology for the optimum positioning.
None of the radar detectoors does transmit signals that disturb the police enforcement equipment. The value for the user is that they are warned to behave themselves correctly, so extra attention is generated for police enforcement. There are always technologies and circumstances that are hard to detect by a kind of equipment, so the user doesn't have a license to speed with such kind of equipment.
I believe that the radar detectors are valuable for frequent drivers, as well for the police and road safety. It will limit the small fines for little speeding. I hope that the lawmakers do realize that the objective is to look for road safety, not for sending millions of small fines.