Hi Not that knowledgeable on GPS devices (Have a Garmin Forerunner 305 for personal training) but looking to understand what the minimum spec is for a GPS device to be worn on an individual so that it can send back location information at regular intervals to a central website that can show positions on maps. Looking for something small, fairly inexpensive and able to be identified with a unique code. I have no clue as to which manufacturers to approach and what specification to give them. I intend the system to work in the UK, if that is relevant. Any help will be greatly appreciated at this very early stage. Thanks Chris Shepherd