Article

2003-12-06 Down Under

DIY cruise missile attracts defence offers

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Posted by phil_b 2003-12-06 2:45:11 AM|| || Front Page|| [4 views since 2007-05-07] Top

#1 Purchase plans? Great, now everyone will have cruise missles. And cheaper than ours!

Posted by Charles 2003-12-6 11:40:28 AM|| 2003-12-6 11:40:28 AM|| Front Page Top

#2 Anybody who goes into the average Hobby store in the country has most of the workings of cruise missle. Your average R/C enthusiast can hobble together enough technology to allow an aircraft to fly unassisted to a predetermined target.

recipe for cruise missle:

1 - off the shelf large scale R/C aircraft
1 - GPS with computer interface connection
1 - small lightwieght computer ( older off the shelf laptop will work nicely.
1- GPS maplink software
1 - custom made laptop to servo interface. ( the tricky part)

Assemble parts - test the system.
Adjust scale of aircraft to accomodate payload.

Most GPS will report speed and altitude accurate enough to provide a rudimentary " Internal Navigation System' to the R/C aircraft.

The only tricky part is writing software to interpret changes in direction requested by the "INS" into servo movements to the controls of the aircraft. There are serveral prototypes that could be used that are off the shelf. Lego mindstorms provides a compact simple to use and easy to interaface module to allow control of "servos" with computer driven commands. You probably wouldnt use it in the final model, but as an example of how the whole system would fit together, it would provide a pretty good baseline.

Posted by frank martin 2003-12-6 1:25:40 PM|| 2003-12-6 1:25:40 PM|| Front Page Top

#3 So you're telling me that when I go, it could be at the hands of a toy airplane cobbled together by jihadis and controlled by a PDA and Legos...

I'm so... not comforted.

Posted by Fred 2003-12-6 1:57:35 PM|| 2003-12-6 1:57:35 PM|| Front Page Top

#4 Well, it's a bit more complicated that that to put together a missile with any accuracy at all.

GPS is only one part of the guidance system. What I am used to seeing called the Inertial Guidance System is based on gyroscopes used to detect yaw and pitch.

The basic principles behind the filtering algorithms which smooth and interpolate the readings from the gyros (usually plural) and the location device (in this case the GPS receiver tuned to the commercial band, non-corrected band) are well known, but accuracy with them is a fine art. Been there, been involved in doing that.

Of course, if all you want is to fly a model aircraft a mile or so and hit anything in the vague vicinity, then that's another matter. But I rather suspect you'd best use that radio controlled model airplane + laptop + GPS in calm weather .... ;-)

Posted by rkb 2003-12-6 2:05:51 PM|| 2003-12-6 2:05:51 PM|| Front Page Top

#5 remember - terror weapons dont have to be particularly militarily effective, they just have to scare the hell out of people. The jihadi designed - donkey deployed missle systems demostrate that design methodology.

As far as gyros go, the germans built versions of this sort of thing using 1940's pre-silicon age technology, Im sure there are all sorts of things today that could provide gyroscopic feedback to a system via a generic computer interface, which would then control the servo controls.

The Jihadis would never go for a solution like this, its much easier to get some hopped up pimply faced, 15 year old beat-off artist to simply drive a truck full of explosives to the local mall. Weapons systems innovation is not their forte, killing innocent women and children with weakminded pubescant males as weapons guidance systems and bulk explosives is their style.

Posted by frank martin 2003-12-6 3:15:26 PM|| 2003-12-6 3:15:26 PM|| Front Page Top

#6 Frank: a single board computer ($100 or so OTS) will work even better.

Posted by mojo 2003-12-6 8:41:44 PM|| 2003-12-6 8:41:44 PM|| Front Page Top

#7 Couple months ago there was a story about how this british RC club had just flown a robot model aircraft across the Atlantic totally under it's own control. GPS and a mini computer. They only used their remote for takeoff and landing. All you have to do is scale it up.

Posted by Steve 2003-12-6 9:28:39 PM|| 2003-12-6 9:28:39 PM|| Front Page Top

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