At this point I'd like to give a big shout out to Charlie Wartnaby, a former work colleague, who 10 years ago was playing around with a shoe-mounted 3-axis accelerometer to measure his running speed. Even at the time, this wasn't a new idea - Charlie found that someone already had a patent on it.

Oh, and re the article, the final few paragraphs seem a bit odd. Boot location sensors would certainly help the Americans not to kill any of their own soldiers or any of their allies' soldiers (a useful feature given their track record), but it's not much use for stopping the aforesaid Hellfire missile wiping out a houseful of sandal-wearing women and their barefoot kiddies.