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GPS Complete Failure in Flight

Discussion in 'Phantom 1 Help' started by tech514, Jul 12, 2013.

  1. tech514

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    I have had the Phantom for a week now and am on my second unit; had to return first Phantom to B&H Photo for an exchange which was not a problem. What happened was this: on my second day and 6th flight, after taking off in GPS ATTI with 6 or more satellites locked and rapid green flashes recording home position prior to takeoff, the phantom suddenly pitched forward after afew minutes of perfect flying performance/response and dove into the ground. Fortunately I was only flying 3 or 4 feet off the ground (grass field) at the time and there was no damage at all. Subsequent attempts to fly were a no-go as it would only stay in Atti mode (despite right swirch being in GPS mode) single yellow flashes, no green lights ever even after complete IMU advanced re-cali and compass recalibrate.

    I connected to the Naza assistant software and the GPS appeared to be "dead" as there was no GPS information under the "Upgrade" tab on the assistant, just dashes under "loader", "Hardware ID" and "Firmware". The Phamtom had not crashed or had any hard landings in prior flights. I opened up the shell and all cables were connected to the GPS module, it just failed. This is disconcerting as it could have happened at a much higher altitude or at greater distance when I might have needed to rely on RTH. Anyone have a similar experience?
     
  2. tanasit

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    Remove the shell and then peel off the GPS cover, most likely the GPS antenna was cracked due to the crash.
    This ceramic antenna is fragile enough to crack even in low level crash in particular the top shell got hit.
     
  3. FrankB

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    My guess is that it flew into the ground because you accidentally pulled back on the throttle (left) stick. Whenever I let a newbie try out my Phantom, they invariably do that- the quadcopter starts to drop, and they pull back on the throttle, rather than pushing forward. Unlike some quadcopters, the Phantom has no instrumentation that prevents you from flying it hard into the ground- so you need to be careful.

    To help avoid disasters, I have the second ATT button on the right control mode switch (S1) programmed to kick the Phantom into Return to Home (RTH) Mode. Then if it looks like someone is loosing control, I just reach over and flip the switch over to RTH.
     
  4. jumanoc

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    I had the same issue. Zero GPS at all. No green lights even when right stick sets to GPS mode. Naza Assistant displayed GPS NEEDED every where. ATTI flying worked OK. Follow my steps.

    I verified every failure point: GPS (no cracked), GPS wire (OK continuity signal with tester), Compass, (OK but no calibrating) :shock: I bought a new compass with litle cable (US15.oo in ebay), and figure what, the error was cause by compass grey cable that goes from GPS to compass (1 line was broken in somewhere). Just replaced compass cable and GPS become alive. advanced calibration and restoring default parameteres were required. Now it is OK.