@Dave 126 Re: Integrated satnavs are way better
Are you seriously trying to defend this?
1) this is an inbuilt car sat-nav. It doesn't take readings from the CAN-bus (or any part of the OBD). It's a GPS it doesn't need to
2) What information does OBD say about 'any wheel', tyre pressure maybe, ABS and traction control? so what? What it doesn't tell you is the rotational speed of a wheel.
3) How will a car know where it is when it starts up - only if it knew where it was when it stopped, which it doesn't?
4) Satnav units built into a car don't have digital compasses, they use GPS to provide direction information.
5) Cumulative errors can't be reduced - unless you constantly tell the sat nav where you are (provide a point of reference manually). You don't enter a current location on any sat-nav - it knows where you are, it's a GPS!
6) A few companies tried to make a basic navigation system that worked a little like a tachograph. They didn't work. With GPS and SA turned on they used some speed and turning information but they didn't work very well either.
7) Do you really think that a SatNav manufacturer is going to spend 80% of their R&D budget trying to figure out a way of making the satnav work if the GPS receiver stops working by connecting in to compasses, wheel speeds, odometers, tyre pressure sensors?
8) You really think you can go for 6 weeks with a satnav using even the most amazing technology to read car sensors and still get any semblance of an accurate location?
Dave, with your silver badge come responsibility, use it wisely - this is a tech site not a youtube comments board.