LIDAR Saturation

TSi+WRX · #6 (**permalink**) 2008-12-11

Quote:

Originally Posted by Veil Guy

Sorry, but I am not inclined to believe that such a circumstance could ever generate a higher speed reading being indicated on the officer's lidar gun.

+1.

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Quote:

Originally Posted by Veil Guy

I have targeted highly reflective vehicles while the sun was behind me and low in the sky and have found the in certain circumstances the range of police laser can be reduced by as much as 50% just by the angles. When the angles change sufficiently enough where the reflection goes away, the range increases again......

I believe that, in general, these kinds of lighting conditions, will tend to always favor the driver and not the lidar operator.

This is most interesting.

Don't get me wrong - I'm not doubting your experience.

IMveryHO, nothing beats real-world experience, in this matter.

However, I am having a hard time reconciling what you've seen, with what's seen of the performance of laser jammers.

In every test, to-date, including not only GOL but also many other hobbyist groups, all jammers' (both LED-based and laser-diode based) performance have been affected, in a decidedly negative manner, in instances of "sunlight interference."

What, then, is causing this?

If the overall situation should favor the driver, via the physical/real-world implications of AGC (which stands to-logic), why, then, is the effective performance of the jammers so decreased?

Yes, I understand that the jammers, upon "seeing" bright sunlight, also employs similar "interference" algorithms - ones which, as we've seen in hobbyist testing (as well as is a fact divulged direct from some jammer makers' own confessions), causes the jammer to be considerably less effective..... but wouldn't the fact that the effective range reduction in the detection capability of the police LIDAR, under such conditions, at least make it all a wash, instead of making the situation decidedly UNFAVORABLE for the driver?

The other possibility would be that the gain control makes the jammer's job even harder - that it causes the LIDAR to "see" even less of the jammer's output.... But again, this is a situation which, to me, is not in favor of the driver.

Your thoughts?

bhaubrich · #7 (**permalink**) 2008-12-11

Gentlemen, Thank you for your replies. I do not believe that I have decribed the situation very well. The officer is facing almost directly into the sunlight using the LIDAR detector. Me (target vehicle) have the sun behind me. I believe that the LIDAR detector may have been saturated by the direct sunlight causing and erroneous reading on his detector. Thus issuing me a citation for 28mph in a 20mph zone. Is it possible for direct sunlight to cause erroneous readings on the LIDAR detector? Please see attached link of the photo

taken shortly after citation was issued. Thank You for your expertise. With Best Regards, Brad

Flickr: bradley_haubrich's Photostream

bhaubrich · #8 (**permalink**) 2008-12-11

Ok, well I don't have a LIDAR jammer. I am just wondering if the officers LIDAR gun used to issue the citation could possibly have error introduced as a result of taking a measurement while facing into the sun. Is this possible? No jammers involved just wondering if the direct sunlight may have caused the officer's equipment to read inaccurately? Your thoughts?

Best Regards,

Brad

Veil Guy · #9 (**permalink**) 2008-12-11

^ The sun could not, would not, create a situation that a speed reading would be higher, period.

Sunlight IR is CW (continuous wave), laser pulses are discreet pulses.

The only time sunlight IR could be interpreted as a legitimate police laser source striking a "laser sensor" is when you are moving in a vehicle and the sun light gets repeatedly obscured by the surrounding trees at a particular frequency that may appear as a pulse-train. That's why a laser jammer or a laser detector may occasionally go off (false) because of such situations.

But sunlight in and of itself causing a higher than indicated speed reading? I'd put that in the impossible category and I have handled police laser since the early nineties with the first generation LTI Marksman. Now that we're into generation III or generation IV, the likelihood is even more remote.

Sorry to be the bearer of "bad" news, but I believe this to be the reality and I believe you are spinning your wheels, on this one.

I would recommend that you spend your energies on arranging for a plea-deal (reduced/amended violation) instead of making a case for St. Elmo's Fire.

Veil Guy

steagall1000 · #10 (**permalink**) 2008-12-11

bhaubrich,

Veil guy is right sun light can reduce range, but it will not effect the guns speed reading. I have shot my Pro Laser II and Ultralyte at cars in the sun, and it does not effect the guns speed reading at all. So an erroneous reading is not likely.

Quote:

Originally Posted by bhaubrich

OK Guys, Yes I mean LIDAR. I believe that the officer in my circumstance was attempting to target my vehicle with the sun behind me (target vehicle) and the officer. I took a photo shortly after the citation was issued showing the bright sunlight. I will try to post the photo a little later. I believe that the laser detector on the officers LIDAR gun may have been saturated by direct sunlight causing an erroneous error. Is this possible or even probable in your opinion? Thanks for your help. Best Regards, Brad