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Phantom 3 v PV2+

Discussion in 'Pro/Adv Discussion' started by paulsheaves, May 2, 2015.

  1. paulsheaves

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    Hi guys,

    I'm about to buy the P3 having previously had the pv2+ which I had numerous problems with namely detecting the GPS satellites (still loved it though!)

    I am not an experienced flyer and have some questions for those that have owned both...

    1. How much better is the phantom 3 at picking up satellites than the pv2+ was/is?

    2. What happens if you take off with full GPS lock, but lose the GPS lock mid flight, is there a way of getting the phantom home without having to manually fly it in (what I think is called) atti mode?

    3. In effect, what I'm asking is, if in atti mode/non GPS mode, will the P3 return to home if it goes out of range?

    My reason for these questions is that I have had many previous panics when flying the PV2+ - it would lose satellites in mid flight, and I would be facing in a random direction and the phantom would start drifting away towards out of range, I found it hard to master the controls if not facing the correct way etc...

    Whilst I'm at it, feel free to provide any other feedback on what's better on the p3 than the pv2+, I'm very excited but want to be safe.

    Any help appreciated many thanks,

    Paul
     
  2. Buzz313th

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    The P3 is a great product and all your concerns above are what you would like to hear.

    1. It has the capability to pick up standard GPS and GLONASS Sats.. that's twice the available Sats than before

    2. No GPS and the flight system is flying in Attitude mode with heading correction, altitude correction but no horizontal position correction.. The craft will maintain "Attitude" in a hands off situation..

    3. The P3 will enter "Failsafe" mode (Go Home Mode) in different user set and or failsafe situations.
     
  3. Meta4

    Meta4 Moderator
    Staff Member

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    1. Lots. The P2V+ needed the foil mod for GPS to work properly. DJI have taken care of that and now also use Glonass satellites so there are twice as many sats to play with. Users report great GPS performance.

    2. You are extremely unlikely to lose GPS out in the open. You'd have to fly under tree cover or in a canyon.
    In the unlikely event that you did lose GPS your P3 will be in atti mode and you can still fly but this really is unlikely to happen.

    3. If the US and Russia switch off all their sats or you fly into a cave or a deep forest, your Phantom won't know how to come home. If out in the open this is what the manual says:
    If you fly out of the limit, you can still control the Phantom 3, but cannot fly it any father. If the
    Phantom 3 flies out of the max radius in Ready to Fly (non-GPS) mode, it will fly back within
    range automatically.
    If the Phantom 3 flies out of the max radius in Ready to Fly (non-GPS) mode, it will fly back
    within range automatically.

    What's better? Everything.
    It's a whole new bird but in a familiar package.
    read this for a starter ... http://www.phantompilots.com/threads/first-flight-observations.39878/unread
     
  4. paulsheaves

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    Hi Meta,

    Awesome reply tyvm.

    So basically you are saying that if the pilot sets off in GPS mode it should never rely lose its GPS lock (my pv2+ would lose its lock regularly mid flight).

    However I am very confused by the manual quotes...


    1. The first sentence - If it flies out of range the pilot still has control but cannot fly it any further? - Does the phantom 3 simply hover when it gets to the edge of the range? How can a pilot still have control but cannot fly it?

    2. If you are in non GPS mode and fly out of range, how does the bird know to automatically fly back in range? - I was under the assumption that this only happened in GPS mode not non GPS mode... - RTH happens regardless of GPS or not?

    Many thanks for helping a newbie,

    Paul
     
  5. Buzz313th

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    1. The Flight system won't let you fly it further away from Home position, but it will allow you to fly it closer.. Once you get to the horizontal distance limit, it will act like it hit a wall..

    2. If you lose GPS, then the Bird does not know where it is in Horizontal space.. and if it enters failsafe it will descend for a landing... or, you can use heading cues to bring it back to a stored heading reference.
     
  6. paulsheaves

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    Hi Buzz,

    I'm sorry for being confused...

    What about height limits, same thing?

    Meta suggested that the bird would automatically come back into range in non GPS mode, but you're suggesting it will descend and land where it is?

    The good news sounds to me like there is absolutely no way it should lose GPS in the first place, so, in my mind it should ALWAYS RTH automatically as it will always be in GPS mode...

    Hope I'm right?!

    Many thanksthanks
     
  7. Meta4

    Meta4 Moderator
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    Those manual quotes were relating to limits you can set and change or the 500 metre height limit that is hard wired.
    If you don't set limits, you can fly until you run out of battery or signal.
    If you hit limits, the Phantom won't go further in that direction but you can turn it, go up/down, bring it home etc.

    2. My take is .. you can choose to fly in atti but if you get out of signal range, the Phantom uses GPS to come home.
    The sats are still there even if you weren't using them.
    No point programming it to act dumb and land if it is able to come home in that situation.
    This sounds pretty clear:
    If the Phantom 3 flies out of the max radius in Ready to Fly (non-GPS) mode, it will fly back
    within range automatically.
     
  8. Buzz313th

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    Without GPS, the bird does not know where it is in horizontal space.. It only knows where it's pointed (Heading through the compass), If it's moving horizontally via the visual sensors, if its moving vertically via the barometer and it's pitch, and roll, via the accelerometers. If there was a GPS failure (Highly unlikely with the P3) then the safest thing for it to do is slowly descend to a landing where it stands in space.. This is because, it would be more dangerous for the drone to try and calculate it's position and return home.. and probably impossible with the sensors available.
     
  9. Buzz313th

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    And Meta4 is correct.. if you choose to turn off GPS but the bird still sees the satellites, then faiilsafe will turn the GPS flight mode on for a safe return to home... But this is not the case if the drone is blind to the required Sats for an accurate GPS fix.
     
  10. paulsheaves

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    Ok so,

    With GPS it will always return home when it reaches out of range.

    With non GPS mode but still receiving satellites (just the pilot is choosing not to use them) it will also fly home.

    With non GPS and also not in a situation to receive GPS, the p3 will land itself vertically downwards wherever it is (best hope you aren't above water!)

    Conclusion - regardless of which mode, the p3 will never ever continuously fly away into the sunset never to be seen again - this is what I'm sure my pv2+ could have done previously when the sats failed...

    Have I got it now?!

    Does "fail safe" activate automatically on the p3 or does the pilot have to set this prior to flight?

    Buzz, Meta thank you so much :)

    Paul
     
  11. Buzz313th

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    There are options for failsafe parameters that are userdefinable. The vehicle will go into failsafe if it is isolated from the operator controller or controllers or if it sees conflicting flight parameters. Once it gets back into a situation where the operator has potential control, the operator can actively take control of the vehicle or allow it to continue in Failsafe. And as you know, you can override flight modes and I believe on the P3 you might be able to execute failsafe mode from the operator controller.