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Stupid help needed

Discussion in 'Phantom 2 Vision + Discussion' started by Timmydz, Jul 13, 2015.

  1. Timmydz

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    Please don't flame me to bad, I already feel bad enough, and just seeking any advice on what reaction phantom might have in this dumb situation......

    I was just putting along my backyard with phantom2V+, I did not establish sats, was not ready to fly, home point not confirmed. Had her up about 15' to work out some issues w/ my camera. Why I had it out flying in 1st place, just up to play with camera repair, and was to impatient to wait for ready(I know, I know, kicking myself!!)
    I was hovering in Naza (switch up in gps) even though I only showed 6 sats on iphone.

    My question is, in Naza what will P2+ do if no gps, no home point? Will it just hover and land when out of battery? Will it auto land? I was just on the cusp of that 30 meter(Ibelieve) that it may autoland, not sure, but I think I was just past 30m. I checked wind log at that time and it was only 1mph, so I'm longshot hoping it may of just come down close to where I lost it. I have been looking around, but it is dense trees, so slowly mapping out search grid.

    Again any help appreciated, I already know what I did was stupid. Thanks in advance for any help.
     
    #1 Timmydz, Jul 13, 2015
    Last edited: Jan 12, 2016
  2. SteveMann

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    You didn't say what finally happened to the Phantom. Is it in the tree, or did it take off for who knows where?

    If you didn't establish home point, then home is wherever the random data in the homepoint memory is pointing. I don't know if it initializes to zeros or something else or random noise. (I would initialize the home point at power up to all ones, which would be an impossible location.) So if it flew away, start walking toward the intersection of the prime meridian and the equator.

    But the odds are that it would set a home point with six satellites while you weren't looking.
     
  3. Timmydz

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    Thanks for the reply. I haven't found Phantom. I was primarily wondering if you think due to the settings, situation, etc. would it like you mentioned find a new home point somewhere near in the trees, and come down there, OR would it in your opinion just kind of wildly fly around? The reason for all this is I'm wondering if my planned recovery missions is futile.

    Thank you again for any help.
     
  4. SteveMann

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    How long was it hovering? Could the battery have gone gone critically low? How much time was left on the battery?
    I know this is rhetorical, but your phone number is on the Phantom?

    In this case the safest recovery is to climb.
     
  5. Timmydz

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    Battery was at 75%. Hovering all told 2 minutes maybe a little less.
     
  6. RoyVa

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    Go to the app settings and look at find my Phantom. It's last known location will be noted. Look at where it started from and then it's last know location. Mentally draw a straight line and head that way. Look up down and all around. If the location is still there you may get lucky. You would have had a better chance had you done this right away. Good luck and let us know how you do.
     
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  7. Timmydz

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    I should have mentioned, find my Phantom only shows a mark where I lifted off from.
    So, again ultimately, I'm trying to figure out what characteristic it would have in no sats, no home set, will it just hover and descend, or will it keep flying about looking for a home. Thnaks.
     
  8. RoyVa

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    It most likely retained its last home setting and headed that way.
     
  9. SteveMann

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    Not likely. Non-volatile RAM is expensive. The home position is probably in RAM because it is transitional data and gets overwritten in normal operation, so when you power up the value is anyone's guess.
     
  10. Timmydz

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    That "value" of it being nothing I guess is the answer I'm looking for to solve this riddle. Meaning if NO home position would make it do " _______". My hope is sit still and eventually just come straight down. My fear is, it will just drift or dart about looking for something it can never find that doesn't exist. I doubt I'll get an answer, but maybe I'll reach out to DJI and see if they can tell me.
     
  11. SteveMann

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    If you didn't set a home position, then the drone will use whatever data is in the memory location for the home position. We went off on a tangent about what that could be. But in any case, if you have satellites and an RTH is triggered, the Phantom will make a straight line for whatever it thinks the home point is. It will not wander about.
     
  12. N017RW

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    It would be poor coding practice to allow a 'race' condition or random data to be generated for that data after power-up.
    Likely position registers remain all zeros. Fail-safe would not RTH and instead land in current location + wind drift.

    We do know that when you have 6+ sats locked and you increase throttle >10% for take-off the location is stored. DJI Wiki states this.

    To me the 'test' is taking-off before you have 6+ sats and see if you get the second set of rapid flashes (if in Naza mode) at some point after 6 sats are locked while in flight.
    If not, I would surmise the location registers to remain all zeros until [if] a manual (re)set of home is initiated.
     
    Timmydz likes this.