http://www.trimble.com/gps/
In reading through the posts, I am amazed at the extent of lay knowledge in the GPS technology. At the same time I am astounded at the misconceptions some hold regarding the subject. Even more amazing is the fact that rank amatuers can utilize the technology as an appliance and get great results! That says a lot for our engineers who have designed an appliance that is so user friendly. If you want to know what is going on with this device however, the above link is a good place to start.