sknyfats

I've see the thread about "tire" & "wheel" sizes affecting GPS, but I do not buy it.

I have spoken to Ford customer service - who said I needed my GPS "recalibrated", and just left my dealer who did a "GPS module reprogram" - and I continue to have the same problem:

My location is off anywhere from 200 feet to 2 or 3 blocks - which affects how I'm navigated. My Nav is essentially useless 75% of the time.

GPS is a fairly simple technology. It's been around long enough that its easy to setup, configure and use reliably. So why is my built in GPS in my $50k truck so screwed up?

There is no "calibration".

There is no affect because of wheel size.

My GPS receiver picks up satellites and fixes my position based on those signals.

The problem is a MFT programming error. They need to fix it.

Here's some examples. Love to hear of others with the same issue & hopefully a fix someday. Maybe 3 years later, like the EcoBoost CAC issue? No, longer probably since its not as much as a safety issues....

The images below are on a clear sunny day. I have 2 other portable cheap GPS units that are working perfectly.

*please, no debate about how tires/wheels affect things. That's BS & I don't want to hear that load of crap

I am actually on the big orange line, NOT to the right.



I am actually on the red line, NOT the railroad tracks to the right




I am actually on the green line, no in a house on a side road to the right.




I am actually on the green line, not to the left of it & driving across a 4 lane highway!!

Mark S.

I've had the same problem lately. I'm a commercial pilot, so yes, tire size etc. Does NOT affect position. GPS problems, Not recognizing the iPod, POI icons disappearing randomly, can't hang up a phone call. All very annoying on a $50K vehicle. Dealer gives me the glossy eyed stare. Come on Ford/Microsoft, get with the program.

2011LIMITED#288

theres a calibrate button in my menu somewhere, 2011 though...

Tweak

Here comes the wheel stuff you didn't want.

The system uses wheel speed data, and compass data, called reckoning with GPS. The problem is the reckoning data should supplement the GPS, and it appears to have priority. I have spun my rear wheels on ice and watched my icon move, while my truck doesn't move an inch.

Here is a factoid from ford media:

. How it works: For a navigation system to deliver timely instructions, the computer must know the location of the vehicle. Usually, a Global Positioning System (GPS) receiver in the vehicle is used. In some systems, dead reckoning is used, either on its own or in conjunction with GPS. Dead reckoning uses wheel speed sensors and/or accelerometers to infer vehicle movement and track the location of the vehicle. Dead reckoning, when used with GPS, improves accuracy and provides more precise route instructions than GPS alone.

The site is:

http://media.ford.com/article_displa...rticle_id=2616

GPS is satellite based. Yes. Ford navigation uses other data as well. The combo and how it is used is the problem.

sknyfats

Right - blah blah blah. No offense, but that's BS. I'm familiar with dead reckoning - we used it when I was in the Navy on my boat. That is not the issue. Besides, my wheels/tires have 0 affect on my speed & mileage. They are dead on - I've verified this. Ford is passing along a line of hooey.

zxd9

OK, I just went on a trip and use my phone for GPS functions. NEVER had an issue with it keeping track of where I was on the road before this. On that trip two weeks ago it kept placing me on the service road next to the highway. Here is my theory: GPS satellites can have varying degrees of accuracy depending on how much the .gov wants us to have. Maybe with all that is going on in the world today, they have changed the accuracy. Just a thought. May be way off.

Tweak

No offense taken. I just want the thing to work too. It is definitely a ford problem.

You should be able to accurately use the nav with whatever tires and wheels you want. The reckoning should just offer enhancements when the GPS signal is compromised or you aren't moving to establish what direction you are facing. But this system is giving reckoning data too much priority some how.

Why I believe it? If I spin my tires when stationary the truck moves on my navigation screen. I bet if you put your truck up on jack stands and put it in drive you would see the same thing. Also, since writing my original post, I have switched from my under-sized snows to my factory tires. Guess what, my navigation works flawlessly again.

It's busted and ford needs to fix it.

jgohlke

I agree that tire size doesn't affect how GPS works, that's for sure. I take my Garmin on the boat and it works just fine...No wheels there!

GPS uses triangulation from satellites. It works for cars, trucks, planes and boats. It doesn't need to be adjusted or reconfigured for each car or boat or plane.

That said, something with the way Ford has implemented their navigation is causing it to be screwy for some folks. It's weird that it works for some people and not for others. What's different about the Nav from truck to truck? GPS works the same everywhere. It's gotta be the way Ford is computing the position data. I bet it's using the GPS position data along with some other data to determine the truck position.

It would be like 3 Garmins where 2 of them have you on the road and 1 of them has you in the woods. It's not like it is a mechanical device. It's all electronic. It either works or it doesn't.

This has to be the way that Ford has implemented it. The only thing different for everybody are the trucks. Something about the truck, is causing the differences. It might not be the tires, but it is something.

2011LIMITED#288

no?

sknyfats

Update: I did the "remove negative battery cable for a few hours" trick - and so far, 100% accurate!