Many of my friends from time to time have asked me on how a Speed detector Cameras functions. So I figured it was time to write about it.
The Radars that is in use all around us, all thought it is invisible. Air traffic control towers uses it track planes both on the ground and in the air. NASA uses radars to map the earth and other planets. Military uses it to detect enemy. Traffic Police uses to track the speed of motorists. Here I am going to give you insights on the speed camera radars.
The traffic radar, which consists of microwaves, travels in straight lines and is easily reflected by objects such as cars, trucks, even guardrails and overpasses. The radar works by directing its microwave beam down the road. As a vehicle travels into range, the microwave beam bounces off the car, and the radar antenna looks for the reflections. Using the Doppler Principle, the radar equipment then calculates your speed by comparing the frequency of the reflection of your car to the original frequency of the beam sent out.
For those of you who sat out the science class The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession.
For waves that propagate in a medium, such as sound waves, the velocities of the observer and of the source are relative to the medium in which the waves are transmitted. The total Doppler Effect may therefore result from motion of the source, motion of the observer, or motion of the medium. Each of these effects is analyzed separately. For waves which do not require a medium, such as light or gravity in general relativity, only the relative difference in velocity between the observer and the source needs to be considered
The concept of using radio waves to detect objects goes back as far as 1902. But the practical system we know as radar began in the late 1930s. Radar technology has improved considerably since the days of World War II.
Traffic radar has limitations, the most significant of these being that it typically can monitor only one target at a time. If there is more than one vehicle within range; it is up to the radar operator to decide which target is producing the strongest reflection. Since the strength of the reflection is affected by both the size of the vehicle and its proximity to the antenna, it is difficult for the radar operator to determine if the signal is from a sports car nearby or a pick up van in several meters away.
Radar range also depends on the power of the radar equipment itself. The strength of the radar unit’s beam diminishes with distance. The further the radar has to travel the less energy it has for speed detection.
The “POP” is a relatively new feature for radar gun manufactures. It works by transmitting an extremely short burst, within the allocated band, to identify speeding vehicles in traffic. Once the target is identified, or “POPPED” the gun is then turned to its normal operating mode to provide a vehicle tracking history.
Laser speed detection is another new radar technology and is not a widespread as conventional radar system. Light Detection and Ranging – LIDAR guns project a beam of invisible infrared light. The signal is a series of very short infrared light energy pulses which move, in a straight line, reflecting off your car and returning to the gun. LIDAR uses these light pulses to measure the distance to a vehicle. Speed is then calculated by measuring how quickloy these pulses are reflected given the known speed of light. LIDAR transmits a much narrower beam than the radar, it is so much more accurate in its ability to distinguish between targets and is also more difficult to detect. But there are lot of limitations to LIDAR equipment. LIDAR gu’s range will be decreased by anything affecting visibility such as rain, fog or smoke. A LIDAR gun cannot operate through glass and it must be stationary in order to get an accurate reading.
There are many different brands of radar detectors available and in many countries; it is legal to use those devices. Some countries banned using radar detectors. One of the reasons for banning radar detector is not because it is detecting radars. Apart from that those devices will detect intrusion alarms and motions sensors. This is a big concern for Govt departments.