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GPS reception

Discussion in 'General Discussion' started by Seedler, Jan 29, 2014.

  1. Seedler

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    Hi,

    I don't know if I being too fussy but I'm wondering if there is a problem with my gps on my phantom 1.1.1.

    How long does it take people to get a good lock with all green lights? The shortest time I have got is just over 2 mins, but most times I only get 6 satellites (one green and one red). Even if I get all green I still notice a red flash every now and then. The thing is I live in the country of Northern Ireland on a high exposed site. I have good line of sight to the horizon in all directions. I did a test with the gps in my car from same location. It can usually lock onto between 8 and 10 satellites and can usually see between 10 and 12. It can also lock on within a matter of seconds.

    The reason I have started thinking about this is because a few days ago I went for a flight. I waited for ages but could only get 6 satellites. Not long after I took off it lost gps lock and went to 1 green and 3 red flashes, then started drifting off. It made loose confidence in the gps hold especially if I was using it for fpv. Anyhow got back and checked the car which told me there were plenty of satellites visible.

    I did a bit of research into the phantoms gps module which looks like a very good one. It can record and store the position and orbit of the satelites for faster lock, which I'm guessing is what the small battery is used for. The data is apparently valid for 3 days. So could the battery be the problem?

    I have also read of some people installing a larger patch antenna. Would this help?

    I have also noticed if I get full lock, then have another flight with fresh battery straight away I get all greens in less than 20 sec.

    I have never crashed or knocked my phantom in any way.

    Sorry for the long post. Is what I'm experiencing normal or should I be getting a better gps experience?

    Thanks for listening,

    Dee.
     
  2. ElGuano

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    Some people have dealt with the same issue. I think some have gone to great lengths to further shield the GPS unit from the other electronics in the shell (copper sheet against the roof of the shell, "grounded" to the negative terminal on the main board). Others have suggested replacing the battery though I don't recall if that was the issue.

    The almanac and ephemeris data must be constantly refreshed. If it's only been a few hours this will be fast. If it's been a few days it can take several minutes. One way to check the battery is to see if you are significantly faster obtaining a GPS lock, if you first power on and attain lock, and then disconnect the battery and reconnect after a few seconds.

    It normally takes me a minute or two to get a first lock, and on my second and third battery it locks within a few seconds.
     
  3. ladykate

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    Location:
    Bellevue, NE
    My P1 takes a minute or two but I get lots of locks. The P2 only takes a few seconds to find them (it will find them in the house with no problem).
     
  4. Seedler

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    Thanks for the replies.

    So does everyone always get a full green lock if they wait for it? Most times I only get 6 satellites, even during my entire flight.

    Like I said I live in open countryside area. Does this sound rite? Should I be getting all greens, or do you think there is something wrong with my bird?

    Thanks,

    Dee.