GPS constellation winking in and out of existence.

[gsmollin]

I'm pretty sure the GPS constellation is always there, but my lock on it keeps winking in and out. I have an '08 M35x. The availability is rarely above 50%, and sometimes I get the "out of range" for a half hour. I don't just lose a satellite, but rather the entire constellation comes and goes. Accuracy degrades in the navigation system when the constellation is "out of range", so this is an important issue. I drive on open roads without tall buildings, steep mountain valleys, or other obstructions. What do the forum members experience in their nav system performance?

BTW, the screen is "info"> "GPS satellite".

[tkeskic]

Have you tinted your windows recently?

if so this is likely your source of issues, I assume you used standard tint and that contains metal in it to get the tint effect; Most newer cars now have the GPS antenna inside the car, and window tint degrades and at times completely blocks the relatively weak signal of GPS. The way around this is to use ceramic based tint if this is in fact your issue

The other issue I have heard of if you had tint done, and had it applied to the front window is the water they use to apply it has leaked into the electronics package in the dash. often this will cause several problems, GPS one of them as it could "fry" or 'rust' some connections; they may not happen to your car right away either, and admittedly a good installer should never run into this issue;

if you have not tinted your windows, are you using a transponder of some sort for toll roads? if so this placed close to the GPS unit "could" for short periods block the GPS signal;

Thats all the advice I can offer short of the "there is really something broken" with the cable, GPS unit, the Antenna or the like, this is also fairly unlikely unless you have taken apart the car for other work however.

Hope that helps somewhat for you;

p.s. you had asked about GPS performance, and I have had the occasional drop out, bad weather, tall buildings, tunnels, under ground parking etc, but all things you would expect, and all things you say are not effecting your car - my system works very well and is always accurate otherwise.tk

[gsmollin]

No, I did not tint my windows. There is a transponder in the windshield, and I also suspected that was the problem, so I removed it as a test, and found no better availability.

How would you rate your constellation availability when on the open road, as a percentage or fraction?

Thanks for responding.

[goM35]

For comparison, I don't live too far from gsmollin, over in Bucks County and my GPS reception is solid. I have an '06 X, with all the option packages. Maybe this will help you narrow down your issue. Good luck.

[khaug]

Our '09 does the same thing - mildly annoying when you'd like to see your altitude and it isn't available. I complained to the service manager when the car was in for it's first oil change and his response was that this isn't a known problem and he had no idea how to fix it.

OTOH the nav function itself works flawlessly.

[gsmollin]

I see there hasn't been any comment on this "old" topic, but my navigation system has continued to degrade in the last year. On a recent trip down the PA turnpike, it lost 1/2 mile between the Norristown and Fort Washington interchanges, which is about 10 miles.

So I complained to my Infiniti dealer in Willow Grove at my 15k service extravaganza. The dealer checked the system, and agreed to replace it. The replacement is scheduled for next Tuesday. I'll keep everybody posted for the results of the re-work.

[gsmollin]

I got my Nav system replaced, and... it didn't fix the problem. Does anybody listen? I told them exactly what to look for, and the problem was still there when I got the car back. So, I went back to the service rep and complained again. Service rep goes to see the service tech, comes back and says, "We'll replace the antenna." Okaayy, there's only two parts, so why replace the more expensive one first, especially when the complaint is about poor reception. Answer: We have to do what Infiniti tells us to do. With this complaint we replace the Nav first, then the antenna.

Well, I lost all the CDs I fed into the music box, and the gas mileage history, is history. And I have to go back now for the antenna replacement.

[WaynesNside]

From what I have been reading, your GPS antenna needs to be repositioned to the left side of the driver dash. Replacing the unit won't fix the problem.

[gsmollin]

OK, what have you been reading? I have not, yet, replaced the antenna, because the dealer never called me back after they ordered the antenna. If it needs to be moved, that would be non-standard, unless this is the subject of an Infiniti service bulletin.

[WaynesNside]

When I did some searching some were saying they did have their cars in the dealer gettin the whole systems replaced with no change. Then some said they relocated the gps antenna to the other side of the driver side dash then it finally got the satillite info.

[WaynesNside]

Check this link out http://townhall.edmunds.com/di...f/133

[gsmollin]

Oh man, that's a sad commentary on Inifiniti's Navigation system. Now I'm really depressed. It looks like replacing the antenna is just as pointless as replacing the system. Well, I'm calling the dealer and b****ing them out for not calling me back on that antenna. I'm going to replace it, since that's all i can do at this point. if that doesn't fix the problem, then, ... well, i don't know for sure what i'm going to do.

[WaynesNside]

In ddcrats post someone posted a link to an aftermarket antenna but I'm not sure if that will work. I'd like to place an antenna on the dash and move it around to see if I can get a satillite to pick it up. My gps info says out of range when I go in the info menu. I'm not sure if the oem antenna will be able to reach up onto the dash if I take it apart

I really don't want to do this myself when I feel the dealer should be the one to fix the problem. Since I don't have an Infiniti dealer around me I can't waste time driving two hours to het nothing done. So I need to find the fix before I figure out what I'm going to do.

[gsmollin]

Well I did get the antenna replaced and it made absolutely no difference. Does anybody know if there is a mechanism to kick this problem upstairs at Infiniti?

P. S. I think it's funny that the spell-checker thinks "Infiniti" is misspelled.


Later: The GPS reception problem is caused by a directional antenna pattern. Obviously, any antenna on a moving vehicle should be omnidirectional, but this GPS antenna is not. You can show this, on your 2008 M, by driving in a very slow circle in an empty parking lot with an unobstructed view of the sky. Take at least 5 minutes to go around a circle, and you will see that the GPS constellation comes and goes. As you repeat the circle the constellation comes and goes at exactly the same compass points. You can turn slowly through a region of pickup, then lose the signal. Then you can backup up through the same region and pickup the signal again.

Another experiment shows that the view of the antenna through the windshield is very narrow. Use a an aluminized-mylar-coated sunshield. Park the car in a direction where you get good pickup. Put the sunshield in the window and the signal goes away. Put the sunshield in the left side window and the signal is good. Put it in the right side windshield and it goes away. Keep folding the windshield back on itself, and pushing it back towards the right side until the signal returns, when you have uncovered the windshield at about 45 degrees right. Now fold up the sunshield as small as you can and slide it slowly across the windshield, from right to left. At 45 degrees right, you will block the signal. Any other position and the signal is unblocked. So the pickup pattern of the antenna is confined to a small sector at 45 degrees right of the car direction.

No wonder it works so poorly. As you turn the car while driving, your pickup pattern keeps aiming at empty sections of the sky. From the information I found on the Edmunds website, moving the antenna makes perfect sense. I can't believe that those sandbagging worthless SOBs at Infiniti don't have fix for this crap.

Later: I took the top ventilator grill off, and the antenna is in there, on the right side near the windshield. When you hold the folded-up aluminized sunshield in front of this spot, the GPS constellation is lost. This is only a small sector of the 4-pi steradian solid sphere ( I know, half of it is below the horizon). However, this is the extent of the pickup pattern of the antenna. I will have to do further disassembly to see if it is feasible to move the antenna to the left side of the top ventilator, where I see a spot for it to go.

[gsmollin]

I drove to work with the upper ventilator grill removed from the dashboard, e. g. with the GPS antenna exposed. The navigation system displayed a 3D lock on the GPS constellation for the entire trip of 25 miles. It has never performed this well before, not even close.

So that's all it is, stupid Infiniti put the GPS antenna behind a perforated metal grill. It may not be necessary to move the antenna to the left side of the grill opening. Maybe I can just move it out from underneath the grill. I have to investigate the simplest fix here. Of course, the absolute simplest fix is to use a plastic vent grill, which Infiniti could have done.

[gsmollin]

This thread has turned into my own mono-blog. No matter, I have good news:
Mission Accomplished

I mounted the GPS antenna on a metal bracket that I fabricated from parts out of an old Errector Set. It is now under the dashboard, about 2 inches to the right of its old position, well away from the offending perforated metal grill. I was able to mount all of this right through the opening under the top ventilator grill. Nothing elso needs to be removed to access the antenna.

I have 3D lock almost all the time, with an occasional dropout to 2D. A lot more testing is called-for, but I am confident of the outcome.

I am amazed that this is such a simple fix. There have to be many unhappy 2008 M owners out there, and some of them will become owners of competitive offerings next time because Infiniti and their dealerships were so unresponsive.

I expect this is my last entry. If you have specific questions about the modification, PM me.

[WaynesNside]

I moved my antenna out of the stock location and cut o hole in the plastic that covered it under the metal grill. So now it pretty much rests on the grill from underneath and I get 3d most of the time too and it works a lot better.

[cruzad3r]

that's the idea - i'm assuming the GPS does not have a good ground connection and with the stupid middle vent cover covering the gps, that doesn't help neither. but good to see you guys have a fix for it. as always, pix and quick tutorial is in order