In 2001, what common electronic device did British engineers use to locate an in-flight American stealth bomber?

http://web.mit.edu/airlines/www/archives/articles/prof-hansman-quoted.pdf
Did I read this correctly? Was it cell phone technology? They refer to it as a passive radar system in the link I site above. I wonder if that has anything to do with the reason why you can’t use your cell phone on a commercial flight?

Thanks for the link!

Sounds like they’re tracking the interference a plane makes in general cellular radiation in the atmosphere. Obviously, that would only work in areas with enough cell network towers. It’s passive because the detection equipment isn’t sending out a signal of its own; it’s just watching/listening to the noise generated by other sources, which planes then move through and interfere with.

For that to work, they’d need to map out the general terrain, location of cell transmission towers (or other electromagnetic sources), etc. And as the article said, the passive system alone would not be able to differentiate between a regular plane and a stealth one… but if you couple that with radar (an active system), then the radar could pick out the conventional aircraft, leaving a relatively high level of confidence if you’ve spotted a stealth plane.

Cool! That was fun!

Oh and no, I don’t think it has anything to do with cell phone use on commercial flights. That’s just typical FUD in the bureaucracy.