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GPS only locking to five satellites

Discussion in 'Phantom 2 Vision + Discussion' started by vadrefjord, May 23, 2014.

  1. vadrefjord

    Joined:
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    Hello there.

    Newbie here.

    Have had the P2V+ for nearly three weeks. All went well until Wednesday last. When I achieved GPS lock, each time I put the Phantom on the ground to take off, the lights changed from flashing green to flashing yellow, and I was only locked to five satellites.

    I can achieve GPS lock after the horizontal calibration (solid green light) but after the vertical it goes back to flashing yellow lights - and five satellites.

    I have updated the firmware, calibrated the IMU, etc to no avail.

    Everything else is working perfectly. This is happening even in areas where there are no buildings, etc.

    Any help appreciated!

    Thanks in advance.

    V.
     
  2. streetreporter

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    I have had a lot less success locking onto GPS sats since upgrading from the Phantom 1.1.1 to the P2V+ -- sometimes it doesn't lock at all in areas where the P1 would lock on sats right away.

    I've sat there for more than 10 minutes at time waiting for seven sats, before just throwing it into atti so I could actually fly.
     
  3. jaykay2PT

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    Location:
    Coimbra, Portugal

    try this web site,

    http://satpredictor.navcomtech.com/

    I have found there is a window of around 1 to 2 hours when, in my part of the world (Portugal)
    I will only have 5 sats.

    Also, my theory is, IF the K-Index is high as well, then even if you have, say, 7 sats,
    the solar activity could knock that count down.

    http://www.swpc.noaa.gov/rt_plots/kp_3d.html

    Only my theory so far, but been checking the results from the satellite predictor against my TomTom 1,
    and I now trust the programme, so adjust my flying times around that.

    Note: I have just motored the satellite predictor forward by 2 months and the "bad window" came forward to midday, so I wil be able to fly at dusk, (when the dreaded wind drops)

    Hope this helps
     
  4. 4wd

    4wd

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    Location:
    North York Moors
    Unless in a perfectly open spot you often get one or two more soon after taking off.
    You should be OK talking off with 5, as above use ATTI mode if concerned.
    I often take off in that mode anyway because sometimes it feels it is trying to hard to correct itself at first.
     
  5. Dirty Bird

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    Location:
    Glen Burnie, MD - USA
    What is your horizon? It is clear all the way to the ground, or are you in a tree bowl, where you can see up but the horizon is all trees? GPS signals are attenuated by trees and other solid objects, and some of your potential satellites can be blocked by objects. Last night I launched from a tree bowl site. First two flights I got a quick 7+ lock. The last flight I waited 40 minutes! She was stuck on 5. When it finally locked onto seven, I quickly launched knowing it would set the home position on launch. Once about the tree line, I had 10+ satellites. Also there are are times when there is simply poor satellite coverage.
     
  6. vadrefjord

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    Thank you all for your replies.

    The P2V+ was locking n without issue in all of the locations - all are a combination of urban/rural/seaside environment.

    The crazy thing is that when it gets dark it will lock on almost immediately.

    Daytime, however, is a different kettle of fish.

    But thanks for the advaice. I will try taking off with the five locked (not too high) and see what happens.

    I'm in Ireland by the way.

    Regards,

    V.