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Lost all Signals and RTH - Look at my .DAT from the drone body

Discussion in 'Pro/Adv Discussion' started by Mz3bo, Mar 9, 2016.

  1. Mz3bo

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    Hello Friends,

    Today I lost the RC signal for the first (almost had a heart attack). I know my RTH and Failsafe at set to 50Meters. However, if you take a look at what the Drone recorded (in the drone body), you can see that it shows 30 meter... however, on the CSV from the remote, I get 50Meter... anyone can explain ?
    The signal lost occured between 12:08 and 12:10

    Thanks
    Capture.PNG
     
  2. flyNfrank

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    What viewer are you using that you are able to view distance from the R/C?

    Also, there is nothing in the above graph that shows a signal loss at 12:08 or 12:10.
     
  3. BudWalker

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    There is more than one field in the .DAT that has altitude information. It's hard to know which field your converter is using. If you use DatCon to convert your .DAT it has a field called relativeHeight that should be an exact duplicate of the altitude in the .txt. DatCon can be obtained by going to DatFile.net/downloads
     
  4. Mz3bo

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    Yes, you can see the drone stopped a few second, and starter to RTH at 10m/s with a 30meter average and straight come back home on the graph...
     
  5. flyNfrank

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    It took me a minute or two to figure out what exactly you were trying to say. When you look at a graph, take how ever much time to need to understand the graphs layout and detail.

    What I saw was...at the 12:08.51 mark the A/C came to a complete stop and climbed to roughly 50m or 164ft altitude. As soon as it reached altitude it continued on at 10mps or 22.4mph.

    The graph is condensed to show Speed by Meters Per Second, and Altitude Meters together on one graph. Take notice that the Altitude reads beginning from -20 up to 40 meters. So if read correctly from -20m to 30m is 50m.

    Btw, this type of thing is real easy to overlook.
     
  6. Oso

    Oso

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    The -20m starting altitude was actually pretty easy to spot right away, and also the 50m delta between -20m and 30m. What I have been wondering for a few hours is why it shows -20m to start? If this graph shows the entire flight, shouldn't it show a start of 0m? Doesn't the Phantom always show a 0m starting altitude and then show altitude relative to that starting point for the duration of the flight?
     
    #6 Oso, Mar 9, 2016
    Last edited: Mar 10, 2016
  7. flyNfrank

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    As we know not everyone launches from the same environment. A graph such as one above was likely created to cater to those that may fly around an area that has -20m altitude. I live next to what I refer to as a ravine or valley that is 100ft lower in elevation. Speaking of which....I wish our A/C displayed True Elevation while in flight.
     
  8. Oso

    Oso

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    If you launched from that valley floor, your phantom would show that launch location as 0, not -100. That's my point. How is the data in this case showing -20m to start his flight. Why isn't the phantom reporting 0m? Are you saying you think the data in the graph was adjusted to show the actual elevation at launch rather than the standard 0 we see normally?
     
  9. BudWalker

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    I mentioned this a few posts back. The .DAT has more than one altitude field. I've seen .DAT files that have the barometer altitude showing a negative altitude. Maybe that's what is being reported by the DAT converter the OP is using. Or maybe the reason is more complicated; I don't really know.

    The relativeHeight field gets set to 0 when the home point is determined and it's values will then be height above the home point. The relativeHeight is also transmitted to the tablet (via the RC) and this is the value reported by DJI Go App, Litchi, etc.
     
  10. Oso

    Oso

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    Thanks sir. Makes sense.
     
  11. Meta4

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    Put your flight record into this: http://www.phantomhelp.com/LogViewer/Upload
    And paste a link here.
    It will be a lot clearer to explain from that.
     
  12. flyNfrank

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    I think you are not recognizing the graph is from Google Earth which has always shown the "amsl" (above mean sea level).

    Also, this particular flight on the graph begins near the 12:00 minute mark and not the actual start of the flight.