When you hit the current location on the GPS do you get the elevation to come up along with the lat. and long. My seems to work only sometimes and then, when it does not does not appear accurate. I can get to the diagnostic screen ( you know...map/menu/cancel) and the elevation on the GPS diagnostic screen does not agree with the current location reading. Any explanation or comment?

 

I know on hand held GPS units like my old Garmin GPS III it can ben in 2D or 3D mode depending on signal quality. Given that the antenna is not on the roof (odd) I could imagine that under certain conditions it may have trouble seeing enough satelites to get a 3D fix.

 

I think there is a built in "error" factor that keeps us from using these GPS systems to deliver tactical strikes with them as a reference. I know that on my MDX I can hit the "signal" in the upper right hand corner and that information will be provided - assuming the vehicle is not moving.

I wonder if this built in error is what is causing your issues.

 

Selective Availability was disabled many years ago. Hand held GPS units are accurate to within several meters, especially with WAAS. In theory car nav doesn't have to be as accurate because it can assume you're driving on a road so it'll simply 'snap' you to it. But altitude data should be available with decent signal. Even before SA was disabled I could easily get 3D nav with my Garmin. Receivers have improved quite a bit since then.

 

I'm pretty sure that 3D navigation is only possible when the vehicle's GPS receiver has connectivity to 3 or more satellites. I know that was the way it worked on my old Garmin unit. I'm going to assume that it works the same way with the GPS in the RL. If your receiver can communicate with only 2 birds, you only get latitude and longitude as well as a larger area for your location. I would use the Navigation manual to verify this, but I seem to have left it in my desk at work.

 

Somewhere in the manual there is a mention that the elevation will not always show due to the fact that in some circumstances, all the satellites are not being received. In fact, I just returned home from a 100 mile trip up the Natchez Trace and back, and can report that I played with "current location" a bit and noticed that when I was "in the trees" that elevation did not report, but did report when in more open areas.

The manual also has a statement regarding the correct elevation, and it too, is dependent on quality of satellite reception.

I have DeLorme loaded on my laptop, and that software makes the same disclaimers regarding elevation.

Fred

 

If they had stuck the GPS antenna in the shark fin where it belongs the reception would have been better.

 

You should be able to get a fairly accurate elevation reading. Here in Arizona, I typically receive signals from about 7 birds, and my elevation is within 50 feet or less. Go into service mode on the Nav to verify how many you are receiving.

 

The government did away with this built-in error about a year ago.

 

SA was disabled by the Clinton administration.

 

When you get my age, it seems like just a year ago.

 

 

Is funny, because one time I was driving in new mexico at top speed, but the speedo was reading 158 mph, knowing that the car is limited to 149 mph, we figure we where going downhill, but you know is hard to tell. Well the NAVI on my TL will tell you the altitude and we were about 2500 ft, but it didn't update automatically, only a snap shot, so we were manually pressing the the screen about every second, so we so the difference an we were going down at about 15 feet per second (not acurate by any means). That is probably why the car almost hit 160 Mph, it was pretty cool.

 

I always keep a backup GPS in my car for just such occasions. Perhaps an aviation GPS would be better for such speeds