Xref: utzoo rec.autos:25733 sci.electronics:8787
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!psuvax1!psuvm!bhb3
From: BHB3@PSUVM.BITNET
Newsgroups: rec.autos,sci.electronics
Subject: laser speed measuring dev. more...
Message-ID: <89331.173931BHB3@PSUVM.BITNET>
Date: 27 Nov 89 22:39:31 GMT
Organization: Penn State University
Lines: 20

I looked up the eye safety information on the info sheet Popular Mechanics
sent me and did some more searching into laser range finders.  The output
power of the device is going to have to be in the 4 milliwatt range.  The
beam is very narrow(0.22 degrees).  The wavelength used is almost certainly
0.91 microns from a GaAs laser diode.  It may also use a 0.875mGaAlAs laser
diode.  Since cars don't have IR mirrors on them, the reflected signal will
be weak, so consequently the detection system is going to have to be pretty
sensitive.  This should make it pretty susceptible to jamming.  The device
can't measure the cop cars speed as of yet, so it will have to be used
stationary.  It seems doubtful that it would be used at night aimed at the
front of the car since the headlights might jam it, plus the cop looking into
the sight would be blinded by the headlights.  Daytime headlights probably
re
will reduce the effective range and might give you time to brake when/if you
vis
visually see the cop car.  There may be something on the system the Navy is
using designed by International Measurement in Aviation Week.

                                             Brent H. Besler
                                             Ford Motor Scientific Res. Lab


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