How Do Police Laser / LIDAR Guns Work?

Most of us have already been through it: Seated, silently fuming, while in the driver's seat of the car. Red and blue lights flash from behind, while an officer writes a ticket in their cruiser. How did he get me, you ask. Could he have even gotten my speed from that far away, you wonder. Perhaps you've gotten lucky and instead cruised past the policeman while he continues to look over the 'barrel' of his laser gun at traffic behind you.

The majority of people hardly understand how police laser guns operate and the way law enforcement officers actually aim for cars for speed detection. If you haven't taken some time yet, have a quick refresher on the distinction between radar and laser.

Police laser, officially known as LIDAR refers to LIght Detection And Ranging. Among the laser jammer community, 'laser' is the more frequently used term, but LIDAR is also acceptable. Police laser guns might seem complex and daunting, however with a little fundamental knowledge of math and an example or two, anyone can understand how it functions and how to, then defend against it.

Let's first take a look at a laser gun to ensure you can learn what the different parts are and the way they operate.

Imagine that you are looking at the front of the police laser gun. It appears much like a big, boxy gun with glass lenses on the front. At the front will be the laser lenses; this is the end that the office points at cars. One lens is for emitting the light and the other is for receiving the light. At top will be the viewfinder, through which the policeman will decide on a target. Below, just like a typical gun, is the trigger. Some guns will also incorporate a stock, which the policeman can put against his shoulder to stabilize the gun. There are numerous types of laser guns, but most have this gun-like setup.

Again, all laser guns have somewhat different looking attributes, but the majority adhere to the same basic designs. Here is a readout where the police officer can see distance and speed readings for their target. Also, there are option buttons that allow the officer to manage various options.

Now that you've got a solid idea of exactly what a police laser gun looks like, you can get a good idea of what it's like to use one. Overall, they are designed to be easy to understand. First, with your eyes only, find a target (usually a fast moving vehicle!). Next, put the viewfinder up to your eye and target the car or truck. When looking through the viewfinder, the laser gun will project a crosshairs or possibly a dot. Put the crosshairs on your target and pull the trigger. If the gun is working normally, you'll have a speed reading in about a second. The device will often produce a beep. The speed reading will pop up either in the viewfinder, below, on the display, or both. The display or viewfinder can also provide the range (distance) where the speed was acquired.

So just how can it acquire your speed utilizing light? Essentially, it just measures distance! If you've seen somebody make use of a golf rangefinder around the golf course, then you've seen the exact same principles in action.

When the laser gun's trigger is pushed, the gun quickly sends out a ray of infrared light. Infrared light is outside of the visible spectrum of light, and so the light which the gun produces is invisible, even at night. This infrared beam bounces off of its intended target, a car in this case, and is reflected back to the gun. The gun is timing how long the beam requires to come back and, using the speed of light, it can determine how far away your vehicle is.

Overall, the technology of the police laser gun are very complex. This procedure of emitting, receiving, and timing the light occurs over a hundred instances per second. That's right - per second. The rate of which this happens is referred to as the pulse rate, and many guns transmit light pulses at a rate of 100-140 per second. Some guns go up to even 200 per second or even higher.