GPS Data Logger Software - BT747

This is a nice one to share.  Wondering where his cat was hanging out when he was away for several days, this guy (Mark Spezio) decided to attach a tracking device to his cat.  The IEEE made a nice audio commented photo/video report of it:

http://spectrum.ieee.org/slideshow/geek-life/hands-on/kookoo-the-gpsenab...

Now he isn't using BT747 - if he were he could reduce the side effect of these large spikes on his track.  And as far as the device is concerned, I couldn't make out which one he is using.  Hints welcome.

Still it ended up being usefull for Mark to have tracked his cat as he discovered where it hangs out in its long trips.  Mark now goes to that area to call out for his cat when he is getting too worried - with success!

Cats are not the only animals being tracked by the way.  Police dogs are tracked too.  There is professional software to help the police use that information to assist them in making accurate intervention reports.
Some pigeon competitions rely on GPS tracking devices too with the nice side effect to know exactly how that bird got home.