I am working on a project which involves accurately locating vehicles and reporting their locations back to base. Basically, it uses a mix of a technology called GPS (global positioning system) and GPRS (general packet radio service, which is basically a way of using the mobile network to connect to the Internet). This is really useful technology which hasn’t been anything like fully exploited.
It has all sorts of useful applications, once you figure out appropriate ways of applying the information you receive from the vehicle. Ultimately, this technology is going to completely change our relationship with the road system. It will allow us to plan journeys much more accurately, and it will allow road use to be controlled in a much more refined manner.
Anyway, learning to program this technology has been an interesting ride, and I’ve been trying to figure out the cheapest way of sending occasional messages back to the base over the GPRS link. Eventually, after discussions with various people, I’ve decided that the best way of doing it is to use UDP. Although UDP is usually not particularly dependable, it turns out that in practice, UDP over GPRS is pretty reliable. The price is a lot lower, because the ‘overhead’ (number of bytes you have to send through the system in addition to your own data) is much less.