Help with lost Phantom 4 Pr0 V2

[Cory51]

[/QUOTE]No-one can see a Phantom at 1.5 miles well enough to tell that it's stopped and hovering.
The recorded flight data should not stop when RTH is initiated.
Any RTH activity should be part of the recorded flight data.
If his comment about flying to the south was correct, that eliminates drifting with the wind in atti as an explanation.[/QUOTE]

Thank you for all the information, I'm still learning this as I go as well. Unfortunately this pilot was very new and wasn't sure what of to do when the drone did not behave correctly. He stated that when he hit the return to home button, the drone stopped and turned towards the home point. It then immediately flew South at full speed. He was watching the drone on his phone with the MapPilot app, and estimated it going about 1.5 miles and then hovering. But I agree that it makes no sense that nothing is recorded, but he could still see it on his screen. This is what is making me think the battery became dislodged when it turned, and MapPilot interpreted some data incorrectly after that.

 

[Meta4]

I disagree. The "starting point" was Waypoint 1. Not the launch point.

Lets look at what the flight data shows:

You'll note the Home Distance circled in red.
This displays the distance from the recorded home point.
You'll also see Waypoint 0 is 20 feet away and 390 ft higher than the starting point
Waypoint 1 is 1037 feet away from the start (which is the recorded home point.)
If you look at the CSV data, that corresponds to these numbers too.

Not that I saw. Again....the "starting point"....

Look at the CSV data. It's all there.

This is also possible. Unlikely I grant you but it can happen and has. This can happen when first launching without an established home point. The "last" home point recorded is in the aircraft. Launching in ATTI mode for a flight will keep the old home point as it was, unless switching to P-GPS and establishing a new point.

Sorry but that's not how the app or the Phantom works.
Neither of your points is true.
Suggest you do some testing.

This is all really mute points, unless unlike myself, you have experience with Map Pilot.......Personally, I have no idea how it operates.

Recording the home point is independent of the app being used to fly.
It is the way the Phantom is programmed to work.

 

[Fly Dawg]

Neither of your points is true.

As should you. Think about it. All other aspects aside. Should you power up and launch in ATTI...( No GPS )......Flying in only ATTI mode. What would happen if you switch to PGP-S, momentarily at a great distance. Would the aircraft create a new home point or if signal was lost immediately after the switch, would it RTH to the home point stored from a previous flight? There would be no home point created in ATTI. That is where I was going with that.

 

[sar104]

As should you. Think about it. All other aspects aside. Should you power up and launch in ATTI...( No GPS )......Flying in only ATTI mode. What would happen if you switch to PGP-S, momentarily at a great distance. Would the aircraft create a new home point or if signal was lost immediately after the switch, would it RTH to the home point stored from a previous flight? There would be no home point created in ATTI. That is where I was going with that.

That's not correct - the aircraft records a home point irrespective of which flight mode you are in. Prior to recording that home point there is none. You can see that in the txt and DAT logs - prior to the home point being recorded, the home point latitude and longitude fields are blank - they don't contain previous home point data. And user-selected ATTI does not mean that GPS is switched off, and the aircraft is still logging its flight track.

 

[Meta4]

As should you. Think about it. All other aspects aside. Should you power up and launch in ATTI...( No GPS )......Flying in only ATTI mode. What would happen if you switch to PGP-S, momentarily at a great distance. Would the aircraft create a new home point or if signal was lost immediately after the switch, would it RTH to the home point stored from a previous flight? There would be no home point created in ATTI. That is where I was going with that.

I've done some testing for you (and was surprised to learn something new).
First I blocked GPS reception with the conspiracy theorist's favourite tool, aluminium foil like this:

As you can see, this effectively blocked GPS sats reception:

You'll note the distance is showing N/A - that's because there is no home point to measure the distance from.
I launched, flew around a bit and brought the Phantom back in.
Here is the flight data:

You'll note the home distance remains at zero - again because there is nothing to measure.
If you look at the CSV data, you'll see that the home point fields show zero - the previous home point is not stored by the app or the Phantom.
When you start up your Phantom, it has no home point until it gets GPS.

What new point did I learn?
When I removed the Alfoil for a second test and started the Phantom in atti mode, the app warned me that I was in atti mode but as soon as I got GPS reception, the top of screen changed to green GPS Ready To Fly.
I launched and the Phantom had full GPS position holding although the Flight Mode switch was in A.
I flicked the switch back to GPS and to atti again and the Phantom lost position holding.
Not sure what was going on, I duplicated the experiment with the same results.
The flight data for both flights shows the Phantom launching in P-GPS mode despite the switch being in atti mode.
It appears that if GPS sats are available, the Phantom won't allow you to launch in atti mode.

And obviously, although the switch was in atti, because GPS sats were available, the Phantom was recording location data and a home point.

 

[Fly Dawg]

the aircraft records a home point irrespective of which flight mode you are in

Please explain that. If you are in ATTI at power up and flight with no GPS reference......then how can an origin be recorded? I am open and respect criticism, but that does not make sense. With all due respect.....that makes me curious as to how that works?

 

[Meta4]

Please explain that. If you are in ATTI at power up and flight with no GPS reference......then how can an origin be recorded? I am open and respect criticism, but that does not make sense. With all due respect.....that makes me curious as to how that works?

If you are in atti mode because there is no satellite reception, no home point is recorded (Alfoil test above)
If you are out in the open with sat reception but have the flight mode switched to atti, the Phantom is still receiving and recording location data.
It just doesn't use it for position holding (except when you launch in atti as I learned).

 

[sar104]

Please explain that. If you are in ATTI at power up and flight with no GPS reference......then how can an origin be recorded? I am open and respect criticism, but that does not make sense. With all due respect.....that makes me curious as to how that works?

If you are in atti mode because there is no satellite reception, no home point is recorded (Alfoil test above)
If you are out in the open with sat reception but have the flight mode switched to atti, the Phantom is still receiving and recording location data.
It just doesn't use it for position holding (except when you launch in atti as I learned.

@Meta4 may have explained it better than I did. I was referring to user-selected ATTI mode, which I assumed you were too since you mentioned switching to ATTI later in the flight.

In general, the aircraft could be in ATTI mode because you selected it, because it had insufficient GPS satellites locked for an acceptable 3-D solution, or because of a yaw/heading error. Only in the case of no position solution does it not record its position, or set a home point.

 

[Fly Dawg]

It just doesn't use it for position holding (except when you launch in atti as I learned.

Much better explanation. That makes much more sense. And @sar104 Yes, I was referring to selected ATTI at takeoff.

 

[upthedowns]

Is there really any need to check anything about the compass or IMU other than any warnings in your app or flashing lights?

Belt and braces. It’s a conscious check I make as part of my pre-flight. Given the number of lost drones due to taking off from rebar (for example) its one I will continue to make.

When your Phantom gets a GPS location fix, it records a home point.
There's no need to check in DJI Go.
Whatever app you are flying with will display your distance from the recorded home point.
Simply check that the displayed distance is about right when you launch.

Good point. However, I find the voice reassuring...I’m usually taking off from my therapists couch ;-)

 

[Cory51]

I found the drone today! it was within 50' of the last coordinates given by MapPilot. It landed feet first, bending the legs and smashing the camera off, then came to rest upside down, there is no apparent damage to it other than that. It will still power on, but there are obviously multiple errors given, the props do twitch on start up. Do I need DJI Assistant 2 to get the flight logs off of it?

 

[sar104]

I found the drone today! it was within 50' of the last coordinates given by MapPilot. It landed feet first, bending the legs and smashing the camera off, then came to rest upside down, there is no apparent damage to it other than that. It will still power on, but there are obviously multiple errors given, the props do twitch on start up. Do I need DJI Assistant 2 to get the flight logs off of it?

I'm not clear how that is at all consistent with what you previously reported:

Yes he said he could still see it on the screen in the MapPilot App, he thought it flew about 1.5 miles straight South and hovered there until it lost connection. I have searched that area extensively and can not find it.

 

[Fly Dawg]

I found the drone today! it was within 50' of the last coordinates given by MapPilot.

Agreed with @sar104 This is inconsistant with your posts description of events by a wide margin in fact.

 

[Cory51]

Agreed with @sar104 This is inconsistant with your posts description of events by a wide margin in fact.

I agree, but the only information I have to work on is what the pilot told me on the day of the incident. He reported to me that he could see the drone going straight South of his screen using MapPilot. Obviously the drone never actually did that. But he did hike over 5 miles looking for it on a cold fall day in North Dakota day, so he believe that is where it went.

 

[sar104]

I agree, but the only information I have to work on is what the pilot told me on the day of the incident. He reported to me that he could see the drone going straight South of his screen using MapPilot. Obviously the drone never actually did that. But he did hike over 5 miles looking for it on a cold fall day in North Dakota day, so he believe that is where it went.

That's very odd - I agree that he must have thought it did that. Is there any chance that it did fly south, and then returned? I suggest pulling the DAT file from the aircraft - that will contain the full record of the entire flight.

Aircraft V3 DAT file: How to retrieve a V3 .DAT File from the AC

 

[Cory51]

I can’t say that it didn’t, but with no data recorded I would say that it is far more likely it just dropped from the sky when the RC stopped getting any information from it. Like I said, the battery was still fully inserted, and there is no damage to the propellers, so I think that rules out a bird strike. I will get the the flight log out of it tomorrow.

 

[DKG13CC]

I've done some testing for you (and was surprised to learn something new).
First I blocked GPS reception with the conspiracy theorist's favourite tool, aluminium foil like this:

As you can see, this effectively blocked GPS sats reception:

You'll note the distance is showing N/A - that's because there is no home point to measure the distance from.
I launched, flew around a bit and brought the Phantom back in.
Here is the flight data: DJI Flight Log Viewer - PhantomHelp.com
You'll note the home distance remains at zero - again because there is nothing to measure.
If you look at the CSV data, you'll see that the home point fields are blank - the previous home point is not stored by the app or the Phantom.
When you start up your Phantom, it has no home point until it gets GPS.

What new point did I learn?
When I removed the Alfoil for a second test and started the Phantom in atti mode, the app warned me that I was in atti mode but as soon as I got GPS reception, the top of screen changed to green GPS Ready To Fly.
I launched and the Phantom had full GPS position holding although the Flight Mode switch was in A.
I flicked the switch back to GPS and to atti again and the Phantom lost position holding.
Not sure what was going on, I duplicated the experiment with the same results.
The flight data for both flights shows the Phantom launching in P-GPS mode despite the switch being in atti mode.
It appears that if GPS sats are available, the Phantom won't allow you to launch in atti mode.

And obviously, although the switch was in atti, because GPS sats were available, the Phantom was recording location data and a home point.

Its been my experience that the P4P and Mavic 2 Pro both are programmed to forgive careless mode switch position on startup/takeoff. For example, Ive launched the P4P V2.0 in Sport mode as far as the controller switch, but I was flying P-GPS initially. I hadto switch to P and back to S to engage Sport. I have launched the Mavic 2 Pro with the controller switch in T mode and, again the AC launched in P-GPS, full speed.

 

[Cory51]

I have tried using DJI Assistant to get the flight logs off the drone, but our antivirus goes crazy when I open it, so that isn’t going to be an option.

 

[Fly Dawg]

but our antivirus goes crazy when I open it, so that isn’t going to be an option.

Turn off your Wi-Fi and/or disconnect the Eithernet cable on the computer you are using to get the dat files. Then disable the antivirus.....if that is causing you issues. Once you have the files you can reverse the process.