Hi Oliver,

My company looked into this project about 18 months ago, it is very exciting but there are a few technical difficulties and cost issues that don't yet make it practical.

You need to link GPS to GSM and use the mobile phone network to communicate with the device, the closest we came to this was a small black box with remote antennas!

It's very feasable but not on a small chip, as you still need antennas to look for the GPS signal and a different antenna to transmit GSM!

Hope this answers your question,

Mark.