Operation Manual

Laser Alerts

The Snooper Evolution incorporates a built-in laser detector. As laser

often requires instant action the device simply gives you an audible or

voice alert whilst the display will flash 'Laser'. No signal strength will be

indicated.

As GPS is not used to locate radar or laser, it is impossible to indicate the

speed limit or count down accurately the distance to a location in metres

during a radar or laser alert.

If you would like to change the alert to a visual alert only press the

MUTE/CANCEL button to temporarily turn off the sound. If at any time

you would like to stop the alert, simply press and hold the

MUTE/CANCEL button.

How Laser works

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. You have probably experienced the reflection time of sound waves

in the form of an echo. For example, if you shout down a well or across a

canyon, the sound takes a noticeable amount of time to reach the bottom

of the well and travel back to your ear. Sound travels at approximately

1,000 feet (300 meters) per second, so a deep well or a wide canyon

creates a very apparent round-trip time for the sound.

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.

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.

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