From: rjgr...@lucent.com Subject: Re: Laser pointers Date: Wed, 11 Nov 1998 16:55:17 -0500 To: "Richard A. Schumacher" <schum...@valencia.rsn.hp.com> Cc: lfresea...@aol.com, c...@dolby.co.uk, emc-p...@majordomo.ieee.org
> Not long ago the US military was using lasers in their war games. I am > pretty sure these were lasers because they were used to confirm "kills" at > long distances. If I recall the soldiers were not required to where safety > goggles. I do not know if these laser war games are still conducted, but > it would be interesting to know what class of laser they were using. What a great opportunity to insert 25 cents for Cubic! The Defense Systems Division of Cubic has the US Army contract for development and supply of the MILES 2000 Tactical Battlefield Simulation and Training System. Think laser-tag with M-16's and M1 tanks! The MILES system uses a laser emitter about the size of a deck of cards clipped onto the barrel of the basic M-16. Other lasers are boresighted onto the other typical tactical weapons (squad assault weapon, 50 cal sniper's rifle, M-60 heavy machine gun, TOW launchers, HUMVEES, Bradley IFV and Abrhams MBT). We really had a lot of fun firing blanks on the M-60; the concussion sets off auto alarms for blocks around! All of the lasers emit in the infrared region, so they not visible. The usable range for the M-16 emitter is 1000 meters, but the minimum eye-safe distance is only 1 meter! Now remember that the laser is boresighted to the weapon. And also remember that the weapon is firing a blank which results in a flash/bang/blast/recoil similar to a live round. Finally, the laser emitter must sense the flash and recoil of the blank before it will emit any energy. (This is to eliminate cheating by zealous soldiers who have been known to flash lights into the sensors or bang on the weapon barrel with a rock.) The Army believes that few soldiers would be looking into the boresight of a firing weapon at distances less than 1 meter. Other unwanted effects would certainly prevail over laser exposure. The other larger weapons have emitters which are more powerful, but the worst case safe distance is still 10 meters. (Again, 10 meters in front of a tank muzzle is not desirable real estate.) All participants in the training wear laser detectors that look like half-size epoxy hockey pucks. A soldier wears a web vest with front/back detectors and a cluster around his helmet. A tank has multiple detectors strung on a long web belt hung around the turret. All of the emitters use a very narrow pulse duration of less than a nanosecond. The bits form a digital word that has a frame rate of around 2KHz. The limit for retinal exposure was placed at 0.3 microjoules for a single burst exposure to obtain the safe distance. Not only is the peak power very low, but the average heating effect is extremely low due to the very low duty cycle. In my EMC lab, I have been able to align simulators using an ordinary camcorder with video sent to a monitor. The camcorder has an optical passband far enough into the IR to easily allow this trick. And, we have never had any eye injuries or camera detector burns. Regards, Ed -------------------------- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: emc-pstc@listserv.ieee.org Date: 11/17/1998 Time: 12:34:42 -------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
