How Laser Works - Escort Passport SR1 User Manual

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.

How Laser Works

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.
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