what is true-time or real time in a gps system?
is it where your vehicle is right at the moment I know you have to pay for that service in some gps not in mine so
Real Time GPS Tracking
Real Time GPS Tracking Tools
is it where your vehicle is right at the moment I know you have to pay for that service in some gps not in mine so
A "real-time" as you call it GPS receiver is one that actually uses the DoD’s (department of Defense) GPS satellite constellation in orbit. In other words, you’re paying for this service with part of your tax dollars, so it’s free.
The GPS receiver receives it’s data from these satellites, and triangulates itself based on 3 or more satellites by using a built in almanac that knows where the satellites are at any given time.
There is no REALT true-time GPS receiver. The commercial GPS recievers (tom tom, garmin, etc) will lag for up to a second or more due to the built-in electronics having to calculate your position… and there is a LOT of math and number crunching they have to do. Then, the GPS receiver has to look in it’s map database, and then display it on your screen. This is as close as you’ll ever get to real time.
Hell, even military GPS receivers installed on cruise missiles lag (though, we’re talking milliseconds for those).
But for all intents and purposes, that is your "real-time" gps receiver.
Verizon touts they have phones with gps capabilities, but they don’t use GPS receivers, they triangulate off cell towers. That is nowhere near as accurate as a true GPS receiver.
Oh, and you don’t get up to date road closures and traffic information from the GPS satellites. It is beyond the scope of those satellites. Most commercial GPS receivers that can show you road closures and traffic info receive a special signal with this data from the two satellite radio companies. Might have heard of them… XM and Sirius…? soon to be only one company since they’re merging.
I don’t know about portable units like the TomTom when it comes to paying for real time traffic data, but I do pay 4.95 a month for each one of my cars to get the XMNav Traffic service to the AVIC Z1′s in them.
I hope that answers your question.