Anyone having an issue with dead reconning and their nav? In the beginning, I had no issues. The yaw and tire sensors worked quite well until the Nav got its lock and plotted.

Over the last three weeks, twice the yaw sensors screwed up and had me travelling in a completely different direction than I knew I was going (making it look like I was travelling through woods and peoples homes). Even when the GPS indicator turned green it did not put me in the right direction or place for a very long time. You should see the system try to lock you on a road you are not even near being on.

Then yesterday, after coming out of a large parking garage in NYC, the yaw sensor worked fine, but it had me several blocks too far. When I finally turned down the Avenue, it had me on the wrong one for a time, but finally corrected itself.

Anyone else having these sorts of problems?

 

That happens when you lose the satellite and the system doesn't know where it started. It happened to me on downtown chicago once. I had parked among the canyons of steel thus blocking the signal, as soon as I came to an open area it corrected itself.

 

vtecbrain is right.

Due to temporary lost to your satellite, you will have this problem for first few minutes. I did have this issue everyday. My garage is in the basement, if I OK to Navi in the garage, I will get this issue in the next 2-5 minutes. Thus, I always activate my Navi on streets now.

I think the great neck area should be fully mapped. This could be the main factor.

 

Also, it is my understanding that in places like NYC and DC the government can and will alter the GPS to give slightly inaccurate readings to prevent the satellites being used against us in an attack. I was in NYC this weekend with the heightened security and noticed it was showing the car off the road but I assumed this was the inaccurate readings.

 

Your all wrong I live in NYC and that sh** happens everyday b/c it losses its signal and by the time I get off the island it knows exactly were I am

 

I realized that you lose the signal in a garage, near tall buildings or mountains, heavy tree cover, etc. If you read up on it, there are two or three different startup routines depending on how long the unit has been off and where it is located. You can get cold starts, warm starts and hot starts. Cold starts take the longest, sometimes up to 3-4 minutes. Warm starts start with the satellite locations already in memory and come up much faster. Hot starts are the fastet, wihch might be where you temporarily lose the signal.

GPS status is noted by the white/green "GPS" indicator just under the north arrow, top left. If it is white, you have no signal. If it is green, you have a 3-D fix with at least three satellites.

All that said, one of the huge benefits of a factory install GPS is the dead reckonning system, which uses tire rotation and a yaw sensor to keep some track of where you are based on where you lost the signal or turned off the car. This is supposed to keep you positioned correctly on the map until the GPS gets its fix.

This has always seemed to work fine for me until recently, when I got some really crazy tracking, as if the yaw sensors did not work for a time, and/or the tire calibration was off. Even after the GPS got it fix, it took a long time before the map was correct.

Note, also, I have heard that as the government alert level goes up, the commercial GPS DOP (dilution of precision) can be increased, but I don't know this for a fact.

I'm just trying to figure out if I need service for the dead reckoning system. -John

 

U got it from Rally?