BMW K1600 Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
641 Posts
Discussion Starter #1
A couple weeks ago, my NAV 6 started reporting elevation at about 50 or so feet below actual. That puts me underwater when riding the beach road. It still locates horizontally on the map. Anybody else seeing that? I wonder if the GPS started using selective availability again or anything like that.
 

·
Registered
Joined
·
698 Posts
It might have the Coronavirus, however, it sounds like a software issue more than anything. I would try doing a reboot and see what happens.
 

·
Premium Member
Joined
·
389 Posts
When was the last time you checked to see if your firmware and software was up to date?
 

·
Registered
Joined
·
180 Posts
Satnavs aren't as accurate in the vertical plane as they are in the horizontal plane. You'll probably have to live with it and rely on other other sources of information to let you know when you are underwater;-)

Joe
 

·
Premium Member
Joined
·
6,414 Posts
I'm pretty sure your elevation readings are within the +- specs of GPS. You don't have a problem.

Duane
 

·
Premium Member
Joined
·
1,605 Posts
I have no idea why it isn't reading accurately. But I think they should be as accurate on z-axis as they are on the x and y axes...or however they're labeled. 50' isn't terribly inaccurate. The only reason it is noticed is because you had a hard reference of the water's surface. Perhaps the sea-level benchmark reference is not globally universal? I know water seeks its own level, but the spinning globe isn't a perfect sphere. Perhaps sea-level is measured at the equator and not locally specific. Just guessing.
 

·
Premium Member
Joined
·
1,087 Posts
Where the original purpose of GPS was to guide military aircraft and ordnance, 50 feet is within the kill radius of naval VT frag rounds. :cool:
 

·
Premium Member
Joined
·
1,471 Posts
A couple weeks ago, my NAV 6 started reporting elevation at about 50 or so feet below actual. That puts me underwater when riding the beach road. It still locates horizontally on the map. Anybody else seeing that? I wonder if the GPS started using selective availability again or anything like that.
Global warming... just saying.. the GPS hasn't caught up with the rising oceans and you are now drowning.. Too bad, you are probably a nice guy, we will miss you on the forum.

Remember justcharlie, the last thing we heard from him was that his GPS was reporting that he was 50' underwater..

GPS is 3x less accurate in the vertical plane than they are in the horizontal, which is to say that it isn't very accurate at all. Close enough for grenades but if you ever did any serious geocaching you would quickly come to realize just how much tom-fudgery happens between GPS readings, and how data is reported on maps. You would think that someone would realize while writing the code that if they can place you on a street at ground level, you probably aren't drowning.
 

·
Premium Member
Joined
·
6,414 Posts
@J-Luv , remember GPS works by measuring time to get a signal from a satellite to the GPS. The lower the satellites on the horizon the less change in distance, ergo, more error.

Duane
 

·
Registered
Joined
·
641 Posts
Discussion Starter #14
I'm still here. Clearly, my GPS was wrong about me being underwater. It's pretty amazing to me that GPS can be as accurate as it is. My understanding of how it works is that the GPS receiver gets a time signal from as many satellites as it can and calculates position based on the differences in time from each - the farther away a satellite is the longer it takes for the time signal to reach the receiver. Think how long it takes for that signal to travel 10 or 20 meters. Not long.

Anyway, I haven't figured out how to get this Nav6 to tell me how many satellites it can see (hear?), but I'm sure there are more rational explanations than it projecting me far enough into the future that the sea level is 50 feet higher.

Cheers!
 

·
Premium Member
Joined
·
1,590 Posts
You'll have to bring your scuba gear next time you ride in Atlantis.
 
1 - 15 of 15 Posts
Top