The accuracy of my navigation seems to have gotten worse over the year that I've owned my car. When I first bought it, I remembered it was pretty accurate. Now it seems my tracking is off a good bit. I live off a main road and my house is off by 400ft. Intersections are off a good bit when I pass through them. Its to the point where sometimes when it tells me make the next turn, its not the correct street coming up but a very close one after that. I drove around the block a second ago to see how many satellites it was tracking. The number usually hovered around 3, but sometimes dipped down to 2 and spiked up to 6. I did a search and read that some people said they were tracking 7 to 9 satellites. Manual adjustment is useless cuz it just becomes off again relatively quickly.

Does the change in season affect how many satellites i'm tracking? Anyone think hacking my navi bootup is causing my inaccuracy? (I dont see how it could though). Any suggestions on what I can do to improve my 400ft difference? I guess the last resort to calibrate it is to take it to the dealer, but whats to say it doesnt go off again? The only thing I can think of is seasonal changes. Will I see improvement in the sping and summer like when I first bought my car and the navi seemed pretty accurate?

 

it all depends on where you are

 

How can you tell how many satellites it's using?

 

Atlanta, GA

 

In the navigation diagnostics menu. Hold down map, menu, and cancel keys for about 2 or 3 seconds. It will take you to the diagnostics menu. Dont mess around in there if your unsure though. Some people say you could mess something up if you dont know what all the options are doing.

 

Hmm in that case I'll tread carefully but thanks for the tip

 

You need 3 satellites minimum for a good fix (3-D). The more sats you get the better. If you are only getting 2 or 3, then I think something is wrong.

I've never checked in my TL, but in my Audi and my Mercedes I generally get 6-8 satellites. It shouldn't really matter where you are, the satellites are dispursed evenly around the planet to give world-wide coverage. You may see less is you have a lot of sky blockage, like in a downtown area with lots of tall buildings or something like that.

Shouldn't be too hard to prove to the dealer something is wrong. Just have them check it on another car on the lot. Do you have tinted windows or anything?

 

I do, but when I had them tinted I made sure to tell them not to use any sort of metallic tint which would block my navi signal from my rear deck. They assured me they would take care of it, and it seemed like they knew what they were doing. And like I said, the accuracy has seemed to have gotten worse over the year. Tint has been on a while now.

 

I would imagine that you're getting a really crappy position with only 2 or 3 birds.

I hate to say this, but the way to test it may be to pull your back tint. Yikes!

 

Arghhhh...i didnt want to hear that. I'll just learn to deal with it rather than pull the tint to test it. I just dont understand why it has gotten progressively worse instead of all of sudden it the tint was the culprit. I wish I had done a satellite tracking test before I had the tint installed so I have a point of reference to start with. I'm going to drive home from work tonight with the satellite tracking on and see what my average satellite number is. Hopefully its just the area I'm at now that is causing my 3 bird average.

 

1) A mimimum of 4 satellites is required for "3-D" tracking. A minimum of 3 satellites is required for 2-D (planar) tracking.

2) Rear window tinting may be your problem, though it could be your GPS antenna as well. You may want to take it to the dealer for repair.

3) Your location in the US is pretty much insignificant. The GPS satellites are constantly in motion, and are providing good coverage across most of the entire planet. That's why it's called the "GLOBAL Positioning System".

4) I'm not sure about this, but cloud coverage may have a minor effect. It does affect my DirectTV reception, but GPS and DirectTV are transmitted at two different radio frequencies.

 

Well I kept an eye on my tracking system on my way home from work yesterday. I averaged probably 4 or 5 satellites driving around on the streets. When I hit the highway I averaged maybe 5 or 6 satellites. I hit 7 once in a while but never more than 7. Should I be worried that I never got more than 7? I know people here have said they've gotten 9 or 10 before.

 

I'm almost 100% positive on this, but your car is not tracking a satellite at all, it's being tracked by a series of transponders attached to various satellites. This is also a problem because the information your car is sending is being bounced off these transponders at roughly 22 thousand miles above Earth and if you are moving these transponders are consistently trying to track your car from their GPS systems. It's really not a problem, but it's the technology in use. Of course the military has the most effective and up to date versions of tracking and GPS. Hope this may give some insight.

 

I think you are thinking too much of satellite TV here. The GPS satellites do not track your position. All the GPS satellites do is transmit a signal containing timing. That's it, nothing is sent back, the satellites do not know where you are. They are purely transmitters, and your GPS is purely a receiver of this timing signal. Your GPS receiver in your car just receives the timing signal from multiple birds to triangulate your position.

 

Unfortunately, this information isn't entirely correct... GPS Satellites are transmitters and everything that we as consumers here on earth use are receivers only. The satellites broadcast a clock signal. Our GPS receivers gather that information and based on the delay of the signal (due to the fact that light actually takes time to travel (speed of light)) from relative satellites. This time delay offset through the use of algorithms will determine a point in space. Check out http://electronics.howstuffworks.com/gps.htm this gives a really good description of how GPS RECEIVERS work.

 

GPS satellites only transmit information. Your car nav system only recieves the signals it doesn't send anything back.

 

Satellite TV is one way as well... receive only. There are only two consumer products that I can think of that actually transmit TO a satellite... The very expensive satellite phones and "DirectWay" which is a broadband satellite internet service... In fact, the older versions only use the satellite link for download and must simultaneously be connected via modem for upload.

 

You don't have to tell me that me that GPS and/or DirecTV didn't transmit. I understand that. It just sounded like that poster was on DirecTV or Dishnet forums too much because of the reference to transponders on the satellite.

DirecTV is a receiver
Echostar Dish is a receiver
GPS is a receiver
XM is a receiver
Sirius is a receiver

Those above technologies only receive a signal from the bird and do not send one back (whith the exception of DirectWay).

I agree and you don't have to try to correct me on something I understand and tried to put that in my post, if you read it.

 

Whatever dude, chill, I wasn't attacking you, just clarifying your misinformation

 

What about my post is misinformation?

I said....

-GPS receivers DO NOT transmit they only receive
-GPS satellites DO NOT track your position
-GPS satellites transmit a timing signal and do not receive (except maybe from DoD)

 

misinformation: "I think you are thinking too much of satellite TV here."

I know what you wrote, I read it the first time, was all correct with the exception to the reference to satellite TV. That's why my post specifically targeted to your reference to satellite TV that could have possibly been constrewed as two way transmission which it is not, hence the misinformation.

I don't know you, I don't know your background, you could build satellites or you could flip burgers, I don't care. I wasn't attacking your knowledge or any of the other correct information you presented. There are some smart guys here, and there are some that wouldn't know the difference between a V-6 and an I-4 even if they were staring straight at it. In your post, you provided some information that implied that satellite TV had two way communication. My intention was to correct that statement and that statement only

 

Peace brother! :surrender

When I posted the reference to satellite TV, I did not mean to make it sound like satellite TV was a two-way communication. I know it is not, but maybe I gave that impression. Thanks for clearing up my misinformation.

 

It's all good, I'd hope you'd do the same for me