What is a Laser Gun?

Tuesday, 30 January 2018 11:14:00 Europe/London

LASER stands for Light Amplification by Stimulated Emission of Radiation The laser speed gun uses a method that relies on the reflection time of light. A laser speed gun measures the round-trip time for light to reach a car and reflect back. Light from a laser speed gun moves a lot faster than sound --about 984,000,000 feet per second (300,000,000 meters) or roughly 1 foot (30 cm) per nanosecond. A laser speed gun shoots a very short burst of infrared laser light and then waits for it to reflect off the vehicle. The gun counts the number of nanoseconds it takes for the round trip, and by dividing by 2 it can calculate the distance to the car. If the gun takes 1,000 samples per second, it can compare the change in distance between samples and calculate the speed of the car. By taking several hundred samples over the course of a third of a second or so, the accuracy can be very high.

Laser police

The advantage of a laser speed gun is that the size of the “cone” of light that the gun emits is very small, even at a range like 1,000 feet (300 meters). The cone at this distance might be 3 feet (1 meter) in diameter. This allows the gun to target a specific vehicle. A laser speed gun is also very accurate. The officer has to aim the laser speed gun at a specific target therefore the officer will only target your vehicle if the officer deems that you are speeding.Laser cone

How Does Police Laser (LIDAR) Work?

LIDAR is an acronym for Light Distance And Ranging. A LIDAR gun emits a highly focused beam of invisible light, in the near infrared region of light that is centered at 904nm of wavelength and is only about 22 inches (56cm) in diameter at 1000 feet (300m). Unlike RADAR which directly determines a vehicle’s speed by measuring its Doppler shift, LIDAR calculates speed by observing the changing amount of time is takes to “see” reflected pulses of light over a discreet amount of time.

Laser ‘Guns’ can be Tripod mounted, Hand held or attached to video equipment in or near a vehice.

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