[joezydeco]

Reading GPS is cheap and easy. Sending information back is not.

Those shipping container trackers use GSM to call home. They're cell phones. What happens when that container is in the middle of the Pacific Ocean?

[fnordfnordfnord]

That's an interesting question. Mini "cell tower" on the ship with satellite link?

[joezydeco]

The original topic here was "why don't planes have GPS trackers on them and constantly report in, if trackers are so cheap and every car/truck/container/phone on the planet can have one?"

How does a plane get data back to the ground when it's 7 miles up and 1000 miles from shore? You have to have a satellite or long-range VHF link.

[KaiserPro]

or you could just use radar, which only requires your own radar to work....