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Lidar- Laser Guns

  1. Aug 11, 2003 #1
    Currently I'm challenging a laser gun ticket. Officer using the gun was on a flat surface shooting onto a vehicle coming down a hill.
    The target is on a 6% incline vs. the officer’s position (flat surface)

    The device used has a range accuracy of 15 cm (device data: http://www.lasertech.com/productline/ultralyte.html#features2 [Broken])
    Isn't it a fact that the exit angle of light is the same as the entrance angle?

    Is it true that over an approx. length of 2000 feet and the target surface(license plate) would make the beam bounce off the ground before the beam returns to point of origin (assuming that the width of the beam allows the beam returning to the gun)

    In any event the information by bouncing off would be different from that information as coming direct from a target as in being horizontal.

    If anybody could confirm or educate me, I would be appreciated.

    (I had once a laser gun manual and it 'demands' a horizontal surface and a tripod for accuracy)
    Thank you,

    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. Aug 11, 2003 #2
    http://members.ozemail.com.au/~rossboss/lasergun.htm [Broken]
    http://www.k40.com/Technical/howlaserworks.html [Broken]
    http://www.radartest.com/ABOUTLASER.html [Broken]
    http://www.acepay.co.nz/pr011019.htm [Broken]
    http://www.zipworld.com.au/~verysoft/speeding/hi-tech.html [Broken]
    Last edited by a moderator: May 1, 2017
  4. Aug 11, 2003 #3


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  5. Aug 12, 2003 #4


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    I don't think a police radar will get a reading from signal that has "bounced off" pavement. At any rate, although you are correct ni saying that the reading the radar gun took of your vehicle going downhill is not an accurate measure of your horizontal speed, I don't think you should mention that in court, as it would only serve to point out that your vehicle must have been going faster than the radar gun indicated.
    Last edited by a moderator: May 1, 2017
  6. Aug 12, 2003 #5
    for Lurch

    In court the point to make is to challenge the credibility of the officer and his knowledge how he is using the gun. He does not have to show that he understands the physics behind it, but the proper use. I have to create 'reasonable doubt' that the way he was using it was not according to the proper use of the laser gun. The proper use has to be in a horizontal stage, mounted on a tripod, etc. Therefore, including other inconsistencies I might have the opportunity to file a motion for 'incompetent' witness. If he had used it according to the manual and the intended use from the manufacturer, there would not be any room for error. Since he did not, there is. Thank you for your input
  7. Aug 12, 2003 #6
    For Adam

    Thank you for all your links. They shortend my learning curve and gave me some valuable info. I continue to study and keep you posted how it went. Still like to know the detailed physics on the laser beam in an offical paper or authority in physics. In any regards you helped me big time. Thanks.
  8. Aug 12, 2003 #7

    Thanx for the link. Very high tech.
  9. Aug 12, 2003 #8


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    Don't tell us 'til later, if you're not comfortable, but do let us know how accurate the man was with the "gun" once things get settled.
  10. Jan 6, 2004 #9
    Lidar Gun

    The case was dismissed due to some other irregularities from the police department. However I'm in a new case with a laser gun and if we get to the issue this time I will let you know if you are still interested. - This time it is even more evident than in the previous case. Happy New Year.
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