A little known fact is... what I thought was a cooling fan whir in the Nav unit, is really the sound of spinning gyros.

Turns out, the gyros, in co-operation with the VSS ( vehicle speed sensor ) are what is doing 99% of the work on your moving map, 99% of the time.

The GPS only takes a fix once every 10 minutes, if the gyros "feel" you are traveling in a straight line. The GPS does not take a fix at all, if the VSS wire is broken, and the Nav feels you are not moving at all.

Only if the gyros are detecting lots of changes in direction ( IE right or left turns ) does the software request GPS validation.

So to Eric, and the original post, you could have 3 issues, or combination there of.

1) faulty or defective gyros
2) faulty or intermittant VSS
3) faulty or intermittant GPS antenna

Least likely, is the Disc in the disc drive. That will either work, or not.

 

Every decent aviation GPS system that I've ever used does a GPS position calculation using the GPS data at 1 Hz. Don't have any idea why the auto units would be any different. If there are any gyro's in the Pioneer unit, they are hardly top inertial quality and so, doing a position calculation using essentially inertial methodology for 10 minutes at a time, would be counterproductive. The main source of error would be directional, of course, and inertial quality directional gyro's are expensive.

 

ok, first off, i have cleaned the disc, I leave the disc in all the time, I can leave it on the map for an hour and it will not update my positon, the compass heading is mostly red, sometimes flashes green for a few seconds. the antenna is not upside down, the arrow moves on the screen in the same way i drive, it turns when i do and all that stuff, just isnt in the right position. I have reset the position by zooming in and finding my location but it only stayed in the right place for a few minutes. also the clock display freezes. that alone has confused me a few times, thinking i am making good time only to find out its an hour later.

 

Just so you know... that part doesn't mean your GPS itself has a lock on the sattelites. Between locks the system uses dead reckoning (I can't spell for beans). That uses information from the ABS and other places to figure out how far/fast and which way the car is moving in between locks. The car will move on the map with no sattilite signal lock at all.

As for the post implying the system uses a gyroscope and hearing it.... I highly doubt it uses anything you'd hear, nor do any of the systems out there. That kind of gyroscope is extremely expensive. They spin at HIGH speed and need tight tolerances and such.... More likely they use MEMS accelerometers and gyroscopes such as this one here:

http://www.analog.com/en/prod/0%2C28...S150%2C00.html

And you just aren't going to hear that thing.... Its a small piece of silicon vibrating... not a flywheel being spun. I think John is just hearing the CDROM or DVD spinning.

 

i knew i doesnt mean its locked on signal, I just stated this to dismiss the bad vss sensor, because it is moving. thanks. I just ordered a ford compatible antenna on ebay for 30$ hope it works ok, should get it this week sometime, I will let ya know if it works. thanks. any other tips appriciated

 

I PROMISE you the 2005-2007 Navi uses gyros.
Whether or not you can "hear" them is up for debate.
There is a service procedure to test the gyros.
I will take a picture for all the doubters out there.

This is exactly how the system keeps your car moving on the map without any GPS signal, such as in tunnel, under bridges, and in canyons.

I only speak the truth, not conjecture.
-John

 

All I'm saying is they are MEMS gyros.... not spinning discs but small silicon chips about 7mm on a side as shown in the link. You can't hear them. I've worked with people who make them in research and they are commercialized as you can see from my link.

And you have to admit we all guess and provide a certain amount of conjecture here quite a bit. I mean while its clear you had proof their are gyros (which I didn't mean to deny at all) you guessed that they would make noise and be of a certain type. I have a strong reason to believe they aren't.... but admittedly neither of us has torn the thing down to see if there are physical spinning flywheels (ala standard gyros) in there... but I'd wager their aren't.

 

Okay. I mis-understood what you were saying at first.
I think we are on the same page now.

 

Hi. I'm new to this forum.

I just purchased a used 2006 FEH, and so far I'm very happy with it, except the NAV. It has factory installed NAV and it was initially working fine. Over the past week or so, though, it tracks my location up to 1/2 mile behind my true location. The NAV senses when I turn, and after I turn eventually (!!) updates my location to the correct road, but still tracks behind my true location. How do I fix this?

Thanks for your help.

 

I thought it just used the speed sensors (VSS) and its own built-in compass for direction. Certainly, that is enough for all the "dead reckoning" it needs when it doesn't have immediate GPS satellite data. Gyros would, to me, be a very expensive alternative with very little overall system improvement.