There are quite a number of manufacturers and satellite tracking companies out there and most have some type of web API.
I've been working with a company tracking equipment from Catepillar, Komatsu, and Sage Quest (Fleetmatics). We have successfully been able to get the API's to populate FileMaker databases with XML data. Most required us to use the Base Elements Plugin because the FileMaker HTTP POST is limited and can't modify headers like you can in Base Elements.
FileMaker server schedule script goes out daily (or however often you want to run it) and finds the vehicles via the web APIs, then finds the job site they are at based on Lat/Long (which was challenging to find which is the closest job that it belongs to), and assigns accounting codes accordingly.
We also display a Google Map with all of this information on it and it is pretty slick. Each vehicle icon is the type of vehicle it is (e.g., trailer, bull dozer, haul truck, track hoe, etc.) and when you click on the icon, up pops info on the vehicle and the job it is assigned too.
We are adding a new manufacturer to the solution, John Deere, which I expect will integrate just like the others did.
Doing projects like this requires learning APIs which are all custom and hopefully well documented. For the less well documented ones, we actually had to use Fiddler and WireShark to analyze what the manfucture apps were doing over the network so that we could figure out the API calls we needed. That was a bit tricky, but fun when we realized it worked.
And learning Google Maps API is rather useful because lots of clients seem to like to map things out. I certainly am not a Google Maps trained expert, but I seem to have made everything work. It is rather fun and challenging. I'm sure this could all be done in Bing Maps too, I just haven't ventured into the Bing Maps arena yet.
Below is a sample map where I clicked on a truck icon and information for it pops up. Google Maps supports live interaction so you can pan and zoom and click on icons to get info about them.
Information from all manufcturers is all displayed in a Web Portal in FileMaker along side the job data dashboard that they put up on a large screen TV at their HQs. Pretty slick and fun solution to have worked on!