Here is a short video that goes over using a 3G modem with an Arduino: 3G/GPRS + GPS shield for Arduino
It's actually not that hard to do. All you need is a microcontroller, a gps receiver for low power electronics, and a cellular modem (to transmit the signal every X minutes.) The 3G + GPS shield for Arduino could probably take care of everything for you, except the battery.
Are there any off the shelf boards that I can use or program to do
something like this? I'm not trying to reinvent the wheel, just
accomplish the task above with the smallest amount of hardware.
If you want to go with something simple, using a Raspberry PI will allow you to use Linux and USB devices, as opposed to using a Arduino where everything would be connected via some type of serial communication. Here is a breakdown of what you would need,
- A Microcontroller like the Raspberry PI because it's basically a cheap computer that you can run Linux on, not that linux is needed. There are 8-bit processors that can do this, like an Arduino. Take a look at Sending SMS via and Arduino. The Raspberry PI has USB ports and some driver support so you can get it built and programmed faster. Depending on how much data you want to send, how quickly, battery life, and a few other things will help you decide what device to choose.
- For the GPS receiver, there are a ton of options, I like something like this GPS to USB because you can mount the antenna away from your equipment (this makes a BIG difference.) Once again, if you want this to be more of an embedded solution you could use a GPS to Serial Receiver with an 8 bit processor controller.
- To transmit the coordinates via the web or sms, etc. you would want a USB cell modem. There are serial ones out there, but they are getting harder and more expensive to find.
- A battery power supply or a regulator to provided power from a vehicle etc.
Another reason for using the Arduino is that once you get everything working, it will be much easier and cheaper to design your own PCB board; if you want to.
That's about it. You would have the controller get the GPS coordinates every X minutes. Once it has the GPS coordinates all it has to do is send them via the cellular modem (messaging rates may apply,) to your web server.
Hope that helps get you started. I made a similar project about 7 years ago, and the biggest problem I had was I used a GPS receiver that was built into my unit, so the entire thing had to be mounted somewhere it could get signal, instead of just the antenna, and this made it hard to position anywhere convenient.