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GPS points wrong direction when stationary

By Trixiem · Apr 08, 2009in Problems/Troubleshooting💬 7 posts👁️ 1,362 views
Posted Apr 08, 2009 · 10:40 UTC#1

can't seem to figure it out, i have a f700bt and an acura RSX. just installed, love the unit so far. little slow but once you get used to it, its an awsome unit for the price.

 

my real problem is that when im stationary the NAVI unit points me in the opposite direction. could it be from my gps antenna being placed wrong? can't seem to figure it out :(

Posted Apr 08, 2009 · 11:14 UTC#2

The 700 depends for 100% on the GPS signal for position and direction of travel. It determines the direction of travel by plotting consecutive positions. If you're not moving, it cannot determine a direction of travel, and so the pointer will be random.. This is completely normal....

Posted Apr 08, 2009 · 11:49 UTC#3

sounds logical. was driving me crazy. i kept thinking for some reason i mounted the antenna backwards... then i thought it about it, you can't really mount it backwards. you can only mount it right side up and upside down... i think.

Posted Apr 08, 2009 · 15:15 UTC#4

Yep, as you said, the GPS antenna has no front or back, it's just a (non-directional) antenna. As long as you don't mount it upside down (it does have a top and bottom side :wink: ), or have metal between the antenna and the sky, you're ok.

Posted Apr 08, 2009 · 19:10 UTC#5
Yep, as you said, the GPS antenna has no front or back, it's just a (non-directional) antenna. As long as you don't mount it upside down (it does have a top and bottom side :wink: ), or have metal between the antenna and the sky, you're ok.

 

Seriously - you can't mount it upside down!? Mine is sideways...

Posted Apr 09, 2009 · 07:45 UTC#6

Seriously - you can't mount it upside down!? Mine is sideways...

You can mount it anyway you like (even upside down on the bottom of the car), but for the best possible position resolution you want your (2 pi omnidirectional, so your 'vision' is limited to half a sphere) antenna to see as my GPS satelites as possible. Look at the sat status (sat reception strenght) with the antenna mounted sidesways, and you will see, that part of the sat's that are theoretically in sight are either not received at all or have a severely degraded signal strength, leading to a bigger positional error.

Posted Apr 09, 2009 · 08:30 UTC#7

In principle, the antenna is only sensitive on the top side. So mounting it sideways, or even worse, upside down amounts to shielding off part of the "view" of the sky. This severly reduces the sensitivity, i.e. the number of satelites you can receive/see at a given time....

 

(and no, you cannot mount it upside down on the bottom of the car.... You might just as well not connect it at all then, as it is a) upside down, and B) there'a a great big shielding lump of metal between the antenna and the sky.... :? )