Has anyone noticed the accuracy of their navi change with the weather? I don't mean a huge change but a small noticable accuracy change? Today is the first day I've had the car that it is quite cloudy and overcast out with rain. I noticed the navi is *slightly* less accurate in regard to mapping my exact position today than it was before. I know whenever there is heavier cloud cover by sat tv goes for a dump which leade me to this question. Anyone else notice this or is it just me?

 

i dont really think so..... the car is a dvd-based, most of the info is from the dvd in the back of the car; that is why there is no reception loss under tunnels

 

The maps are on DVD, yes, but he is referring to his car's position which is tracked by the satellites. I would say that maybe the weather could affect the accuracy of your position just like satellite TV recpetion can be affected but since you are always moving you should be able to get around any bad spots pretty quickly.

 

Thanks for the responsed guys! I was out again today and it was much clearer and partly sunny and I found that the navi was bang on. Much better than yesterday. Interesting!

 

I experience the same thing too. I also wonder what effect, if any that is sizable, does inteference play from the environment (like other signals, electronics, etc).

 

Another good question. Again, the "inaccuracy" I'll call it for lack of a better work is not great at all - at least what I have observed so far. I was following a plotted route on the navi that day and the instructions were still bang on correct and in time for me to follow them but just that "slight" bit off.

 

Mine has been slightly off enough that my postition pointer was off the road and started tracking ticks next to the road. Had to reset the damn ECU to get rid of it months later because it drove me crazy. Was right around the corner from my house....so I saw it show up whenever I left the neighborhood. Hasnt done it since then....but that did happen on a day just like you describe. Overcast/Rainy.

 

The Navigation system relies on the GPS satellite data for it's accuracy in positioning your car. You may notice it being off if the system can't get enough accurate satellite data. This could be due to extreme weather, inside a parking structure, tunnel or the like. For best accuracy most GPS systems require at least two satellites locked on to provide LAT/LONG data and three satellites for LAT/LONG & Elevation. You can check how many you have locked on by entering the Navi setup screen by holding down MAP/GUIDE+MENU+CANCEL and then selecting GPS INFORMATION.

When your system can't get enough satellite data it reverts to "dead reckoning" mode basing your location on it's last good information and your current speed and direction. It should automatically update when it can again get accurate satellite data. Although sometimes you may need to turn it off and back on to "force" it to reacquire the satellites.

 

Once. I mean once ever since I owned the car, Navi told me I was going North when I in fact was drivng south right after I left garage. It fixed itself after about a minute or two

 

It's not so much weather as availability of the satellites. Used to be that the military, which runs the satellites, would intentionally distort the signals so that our enemies could not use the system to their advantage. I've used the marine versions for years that have gotten extremely more accurate, but still are "off" once in a while. It's line of sight and being outdoors that your GPS antenna needs by the way, try and put your hand on top of the roof antenna sometime with the satellite screen up and you will see them all disappear!

Happened once when we were sailing on autopilot on a 40 footer that all of a sudden the autopilot turns the boat hard right 90 degrees, we're like WTH then we notice someone sitting near/on the stern rail with their hand on the GPS antenna pod.