Laugh Off Those Bombs
I convoyed to Ramadi with the Army's 46th Engineer Battalion. My driver was a young soldier who'd fought the Mahdi Army in Al Kut two years ago and was back for his second tour. Before SP-ing ("Start Point"), a lieutenant briefed everyone on the latest Improvised Explosive Device threat.
It seems an insurgent cell out here in Al Anbar has been building sophisticated IR tripwire-activated IEDs disguised as rocks and apparently employing shaped-charge warheads -- hardly improvised at all, if you ask me. Three or four of these things have gone off in the last month, inflicting a number of casualties. Normally in a briefing like this the presenter would detail any countermeasures, but this time he just went, "Umm ... " since there are no countermeasures to an IED like that. You can't tell it from another rock and you can't jam it.
This wasn't my first convoy. Nor was it the first time I've heard scary briefings on insurgent super-weapons. Still, I admit I was a little unnerved. But the 46th troopers just grimaced and shrugged. What are you gonna do?
We rolled out two hours late due to a broken-down Humvee. It was a two-hour drive to Ramadi, and my driver and his crew passed the time munching Chips Ahoy cookies and joking on the intercom. They run these missions almost every day against an evolving range of threats. There are only so many precautions they can take; after that's it's up to God. "Inshalla," my Arab friends would say: "God willing." The non-believers in the crowd can take comfort in the knowledge that, statistically, they're highly likely to survive any given mission.
Still – shaped-charge IEDs disguised as rocks?!
--David Axe
A prior poster mentioned using an IR emitter on the lead vehicle to trigger the IED before troops or vehicles enter its kill zone. This is in fact a possible solution.
You are correct that passive infrared (PIR) detectors don't require a separate IR source to trigger. However, they can easily be triggered by a moving IR source such as an IR LASER or even a very bright visible light (vehicle headlamps emit quite a lot of IR energy along with the white light).
I've worked with PIR detectors in the security industry for nearly 30 years and I can assure you that most of them will trip if a bright IR beam strikes them.
Posted by: Robert L Bass at November 24, 2006 6:40 PM