Stopping green laser pointers in the news--UK

[Wits' End]

Not to open up another pointer discussion.
Interested in the detection, mapping technology.

UK Police fight "laser threat"

Police fight back on laser threat


There has been a "phenomenal" increase in the number of incidents in which aircraft are targeted by small hand-held lasers, according to UK police.
In 2008, there were 69 times as many such incidents as in 2003.
The Civil Aviation Authority has set up a task force to respond to the threat of pilots becoming disorientated.
The police have new devices designed to record and analyse laser "strikes" on their aircraft, tracking their source and leading to arrests of attackers.

Interesting article, especially the frequency analyzing---"It's a little bit like matching a bullet to a gun,"

 

[LowBat]

First time I've seen a video from the pilot's perspective. Didn't realize it was so distracting. I hope more news reports like this are aired, especially to viewers who think they can't get caught and prosecuted for doing this.

 

[gadget_lover]

Interesting article, especially the frequency analyzing---"It's a little bit like matching a bullet to a gun,"

I would think that the freq analysis would not really stand up in court. A bullet match is fairly conclusive, as it picks up flaws in the barrel that are unique. I would think that the frequency range would only be enough to say that a particular laser COULD be the one, but not that DEFINITELY was the one.

It would probably be enough to get a confession.


On the subject of distraction... it would be. You could tell that the beam was quite diffuse by the amount of the windows that were illuminated. I wish they had said how strong the laser was. It's beam was much stronger than my 200mw laser. Even so, as diffuse as it was, eye damage would not be likely.

I wonder why they have never added anything more advanced than a green tinted visor to these craft? It would make so much sense.

Daniel

 

[Patriot]

Judging from the size I'd guess it was well under 200mW. All of the more powerful diodes are much larger in diameter and must be put into a RPL type body. They also stated that the laser was a "cheap pointer" which would be another clue that it was under well under 200mW. I own a 135mW custom in a 14500 body and mine appeared to be more powerful than what I was seeing in the video. Anyhow, it certainly did look distracting from the aircrew's point of view.

 

[RyanA]

I suppose if the device was accurate enough it could pick up slight differences in wavelength from different diodes. I'm not sure what the manufacturing tolerances are on laser diodes, I'd bet there is some variation on a unit by unit basis, but I wonder if it's large enough to be measurable. Although wouldn't even a wavelength produced by the same laser appear different at varying distances? Very interesting item hopefully this will provide an alternate path to restrictions or bans:sick2:. I already think the 5mw limit on laser sights is kind of goofy.

 

[LowBat]

On the plus side the video shows how effected a green laser can be for signaling rescue aircraft at night, provided you're in wilderness or water and not an urban environment. I wonder if tapping out SOS (...---...) would be recognizable in the cockpit.

 

[Benson]

On the plus side the video shows how effected a green laser can be for signaling rescue aircraft at night, provided you're in wilderness or water and not an urban environment. I wonder if tapping out SOS (...---...) would be recognizable in the cockpit.

I doubt it, due to the difficulty of holding a pointer steadily on an aircraft, especially during the off periods. Maybe with a tripod and fluid pan head you could make it work, but those aren't quite plentiful in survival situations.

 

[deusexaethera]

You can get a much better effect on an aircraft by running the laser through a pair of glasses -- it will spread the beam out so it can illuminate a larger area, but it will retain its intensity because it's still laser light. Just in case, ya know.

Anyway, two other thoughts:

1. Manchester seems to be a bad area in general;

2. Anyone who thinks the laser beam can't be traced to its source is an idiot; are these kids so stupid they don't even realize the laser beam travels in a straight line?

 

[2xTrinity]

I suppose if the device was accurate enough it could pick up slight differences in wavelength from different diodes. I'm not sure what the manufacturing tolerances are on laser diodes, I'd bet there is some variation on a unit by unit basis, but I wonder if it's large enough to be measurable.

On bare diodes you might see +/- 5nm lasing wavelength from one unit to anothyer, based on differences in fabrication. But this is not a unique mapping like bullet striations from a gun etc. more of a bell-curve distribution. Also, wavelegnth will be as more or more dependent on temperature as fabrication of the laser, which means this would be worthless as evidence...

Diode pumped solid state lasers, like green lasers, the frequency is determined by the crystals, not the diode lasers used to pump it, and will ALWAYS be within a very small fraction of a nanometer from 532nm. I doubt a helicopter-mounted device would be able to distinguish any green lasers from each other by frequency. Even if they could, for a green, changes in frequency for a green laser will be almost completely dependent on temperature of the laser.

Although wouldn't even a wavelength produced by the same laser appear different at varying distances? Very interesting item hopefully this will provide an alternate path to restrictions or bans:sick2:. I already think the 5mw limit on laser sights is kind of goofy.

Frequency of the laser will be the same no matter what, that's not a problem.

This scheme should not be used as evidence in court...

 

[RyanA]

Thanks Trinity, I had my doubts as well. But I have a lot to learn about lasers. That was a great read. Much appreciated.

 

[luvlasers]

Finally! A government has a rational response and is going after the losers who do this instead of making a blanket law banning lasers that effects every one.

 

[axd]

On the plus side the video shows how effected a green laser can be for signaling rescue aircraft at night, provided you're in wilderness or water and not an urban environment. I wonder if tapping out SOS (...---...) would be recognizable in the cockpit.

Judging from the video, it might be enough to aim the laser in front of the A/C so the pilot can notice the pattern without being blinded by it; because there is no need to keep the laser accurately aimed (which is obviously very difficult for distant, moving targets), it should be more easy to spell out the morse code.

Edit added: see also this post.
Edit2: I remember that cameras are more sensitive to some wavelengths than the eye (eg IR for some common cams); maybe the off-sight beams that are visible in the BBC video might actually be far less visible for the eye, don't know.

 

[God]

Aren't most searchs called off at night!:tinfoil:

 

[blasterman]

I'm guessing the laser used in the video was less than 100mW. I have a 250mW fixed / Q-beam laser and a 40mW hand held. It looks closer to the 40mW.

Shining a laser at a police helicopter is a lot like throwing snoballs at a squad car. You can't do much damage, but it's not very intelligent and is simply looking for a reason to get arrested.

[for the record, I used to throw snoballs at squad cars when I was a kid just to get chased]