BHB3@PSUVM.BITNET (11/28/89)
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. Labg2i@mentor.cc.purdue.edu (Kyler Laird) (11/28/89)
In article <89331.173931BHB3@PSUVM.BITNET> BHB3@PSUVM.BITNET writes: >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. >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 >will reduce the effective range and might give you time to brake when/if you > > Brent H. Besler > Ford Motor Scientific Res. Lab O.k. so what do we paint our cars with? It seems that something more effective than the ECM car bra (for radar absorption?) should be possible with laser systems. What about making the whole area hit light up? I heard of a law in CA which limits cars from using lasers to do this. Would this foul the detector? Are driving light arrays going to be good for dealing with this? A couple 100w lights should put out some substantial IR to the front. It sounds as though laser may be great as an undetectable technology, but it also seems much more prone to useful jamming, etc. than radar. I don't yet understand the theories behind laser speed detection, so much/most/ all of what I say is uneducated curiosity. I await enlightenment... ---kyler