Beltronics Vector 955 - Manual (Page 21)

19
How Laser (Lidar) Works
Laser speed detection is actually LIDAR
(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
quickly these pulses are reflected given the
known speed of light.
LIDAR (or laser) is a newer technology
and is not as widespread as conventional
radar, therefore, you may not encounter
laser on a daily basis. And unlike radar
detection, laser detection is not prone to
false alarms. Because LIDAR transmits a
much narrower beam than does radar, it is
much more accurate in its ability to distin-
guish between targets and is also more
difficult to detect.
AS A RESULT, EVEN
THE BRIEFEST LASER ALERT SHOULD
BE TAKEN SERIOUSLY.
There are limitations to LIDAR equip-
ment. LIDAR is much more sensitive to
weather conditions than RADAR, and a
LIDAR gun’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. Because
LIDAR must have a clear line of sight and is
subject to cosine error (an inaccuracy,
which increases as the angle between the
gun and the vehicle, increases) police
typically use LIDAR equipment parallel to
the road or from an overpass. LIDAR can be
used day or night.