View Single Post
Old 02-28-2008, 12:17 AM   #15 (permalink)
cfg83
Pokémoderator
 
cfg83's Avatar
 
Join Date: Dec 2007
Location: Southern California
Posts: 5,864

1999 Saturn SW2 - '99 Saturn SW2 Wagon
Team Saturn
90 day: 40.49 mpg (US)
Thanks: 439
Thanked 532 Times in 358 Posts
reformed -

Quote:
Originally Posted by reformed View Post
The portable GPS units are less accurate because they don't use the speed sense signal from the vehicle in their calculations like the in-dash ones do. Combining the actual speed sense signal with the GPS triangulation, makes them more accurate.
To me this is counter-intuitive because the point of the GPS is to get a reading that is independent of the car's on board sensors, which may be inaccurate.

I do have one caveat. When I was driving with the GPS, I left it front and center on the dashboard, wedged up against the windshield, to insure good signal strength. If I left it in a side pocket or on the floor, it wasn't accurate. My logic was that I didn't want it to lose the signal before I made a right turn, and then just have it "connect the dots (aka the hypotenuse distance of a right triangle)" when it got the signal back.

CarloSW2
__________________

What's your EPA MPG? Go Here and find out!
American Solar Energy Society

Last edited by cfg83; 02-28-2008 at 01:29 AM..
  Reply With Quote