Rth

[Dazzauk]

Just read that guide for the 1st time and it is very comprehensive and very interesting. However it's not very practical lol.

Basically you should only calibrate it on grass or dirt and the grass and dirt should be level. Not sure about anyone else but in the uk you'd be luck to find such a magical thing

Also no metal objects, pipes, power lines, concrete buildings or other such likes. Good information just again I don't know many places where you just have open in occupied land. And how can you not have your phone in 20ft radius of the bird? Seems like some serious effort lol.

I'm not being rude as I'm a newbie and that guide was written extremely good. I'm just pointing out in the real world that would be a difficult ult guide to follow.

 

[msinger]

the grass and dirt should be level

The ground does not have to be completely level.

I'm just pointing out in the real world that would be a difficult ult guide to follow.

It's quite easy to find a safe area to calibrate the compass. And, since you only need to do it once, it shouldn't be such a hassle. As for the magnetic metal objects, you'll be fine as long as you keep them at least 10 feet away while calibrating the compass.

 

[Dazzauk]

The ground does not have to be completely level.


It's quite easy to find a safe area to calibrate the compass. And, since you only need to do it once, it shouldn't be such a hassle. As for the magnetic metal objects, you'll be fine as long as you keep them at least 10 feet away while calibrating the compass.

Ah ok that makes a lot more sense.

 

[WilliamM]

That's interesting. Thanks for posting. It goes against what other users said on another forum. That was merely from the mouth of other users and nothing official though.

If you're referring to the DJI Forum you will find users on that form tend to do everything by the book and users on this form tend to do things that are more practical and tried-and-true from experience. I just calibrated my compass yesterday the last time before I did that was maybe six months ago and I fly pretty much every week.

Sent from my HTC 10 using PhantomPilots mobile app

 

[WilliamM]

I agree, i guess it's just DJI covering there own backsides.

I think you hit it right on, this way if there's any kind of crash due to compass malfunction they can always point to the fact that you didn't calibrate that morning. Most season pilots do not calibrate every flight, only when changing locations by over a hundred miles or due to compass error.

Sent from my HTC 10 using PhantomPilots mobile app

 

[Dazzauk]

If you're referring to the DJI Forum you will find users on that form tend to do everything by the book and users on this form tend to do things that are more practical and tried-and-true from experience. I just calibrated my compass yesterday the last time before I did that was maybe six months ago and I fly pretty much every week.

Sent from my HTC 10 using PhantomPilots mobile app

Very useful, real world comment there dude

 

[solentlife]

But the manual does say calibrate every time you fly and every time you go to a new location ?

Manual does not say what is highlighted here in red ... but it does say about new location. Page 41

As a trained navigator and compass man - do not calibrate compass unless you have significant distance change from last calibration location. It is not necessary as it takes hundreds of miles before variation changes AND you may just calibrate in poor local magnetic anomalies ...

OK - back to original ...

If your P3 goes into ATTI mode and loses compass - you cannot use the flight line screen to get back as the machine has no heading reference with compass failure.
GPS only gives heading when it has two or more calculated positions to reference to. But if you have no compass - then you can turn away from that course and until GPS gets another set of calculations - it has no heading.

I make the point - but it would be rare for it to be. You can lose GPS - but compass is more persistent and unlikely to be completely lost.

Nigel

 

[msinger]

Manual does not say what is highlighted here in red ... but it does say about new location. Page 41

The following is stated on page 41 in the P3S manual:
"Ensure the compass is calibrated. If you did not calibrate the compass as part of your pre-flight preparations, or if you have moved to a new location since the last calibration."

For me, that's telling me to calibrate the compass before every flight and to do it again if I move to a new location while I'm out flying. The fact that it can mean something entirely different to other people is a good sign that it's poorly written.

 

[solentlife]

each to their own .... I agree that wording could be better ... but I take the practical view and having worked with Chinese - I take it to mean Initial setup pre-flight. Subsequent calibration then based on new location.

If you want to determine whether compass calibration is necessary (once you've done the initial of course) .... then:

A simple marching compass is all you need.

Find that nice spot and stand with compass. Identify a distant mark and reference to your compass.

Now walk around and watch with respect to that distant mark. You are looking for fluctuations of the needle and they can be large or just small. The ideal is to find the largest area that has same result ... calibrate there.

If you calibrate everytime without care - you can in fact calibrate INTO your machine errors that once at reasonable height or distance from that anomaly - the AC now throws a fit saying compass error - where in fact it is now OUT of error area but you programmed in the error.

Be sensible about this ... I own boats and I do not calibrate my compass (each boat has more than one of course) every time I use the boat ... nor do I calibrate after moving distance - in that circumstance I refer to the charted VARIATION at that location. Unfortunately the Variation charts are not designed for land use where more chance of anomaly's.

If people wish to waste time keep calibrating ... risk inputting local errors ... then its not my fault. I have tried to pass on information for informed judgement of the individual. Your choice people !!

Nigel

 

[msinger]

I take the practical view and having worked with Chinese - I take it to mean Initial setup pre-flight.

And, therein lies the problem. Many people will read it as written. To most people, "pre-flight" means something you do before every flight.

I know we could all rattle on about this all day and repeat what is already in the Compass Calibration Guide. I find it easier to just point people to that guide and ask the OP to update it as needed.

 

[solentlife]

And the "http://www.phantompilots.com/threads/compass-calibration-a-complete-primer.32829" you link to itself says do not calibrate everytime .....

OK - I'm a trained professional on Compass / GPS from Navigation career ... and I can honestly say that the guide although reasonable does have some strange parts ... I would give it 8 out of 10 ... good enough.

Nigel

 

[msinger]

And the "http://www.phantompilots.com/threads/compass-calibration-a-complete-primer.32829" you link to itself says do not calibrate everytime .....

Yes, sir. It's a great recommendation.

 

[JohnnyB]

Mine keeps switching to ATTI and GPS for some odd reason only for a few seconds and yet I have 15-19 sats showing. Is this common. Don't want to start a new thread on this basic question

Neon Euc

Yep.. I actually started a thread asking this same question. Mine would be in P mode, and switch to GPS ATTI... 40+ MPH...

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[120CCPM]

I guess that's what happened to me! I didn't calibrate compass, flew it 250m did a RTH and it auto land. It did give out multiple warnings of strong magnetic interference - that's why I did RTH ... a second or two after it started to auto land I lost total contact with AC. It landed on a 3 storey house roof, tumbled and got caught in the roof gutter... lucky it didn't fall to the ground! I now always calibrate... if an error occurs, move to an area where there's no interference

Just a comment here: if you get "multiple warnings of strong magnetic interference", the last thing you should do is to engage RTH, which is a fully-automated flight mode that needs GPS (position) and compass (yaw) to work.
In these situations, you can try to remain in P-Mode and bring the AC back, or - if things get really bad - switch to A-Mode and fly manually. If you don't have experience flying in ATTI mode, just practice when you're not in an emergency situation... ready to switch back to P-Mode if things get out of control.

PS: you need to enable Multiple Flight Modes in the DJI GO app, for A-Mode (and F-Mode) to be available via S1 switch.

 

[JohnnyB]

Thanks for the reply. I doesn't say it on screen (I didn't notice to be honest) but it's only when I check healthy drones it's listed as a regular occurrence but it handles fine and always RTH and does litchi missions so more curious the worried about it [emoji14] [emoji4]

Neon Euc

Mine also didn't show on the screen, but I could sure tell when flying.. she was fast!

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[solentlife]

When you fly back manually with errors of Compass ... take careful note of the distance and whether increasing or decreasing, depends on GPS as well of course but if only a few sats are locked onto - it will work even if you cannot have P-GPS ... also careful note of VIDEO from camera ...

I have had a scary flight where I was out about 2000m and I had to bring her home ... a combo of video and GPS / Compass dropping in / out created a scenario that had me wondering if she was going to make it ...

People above post ... Oh just fly along the line and bring her back ! ... Switch to ATTI and just fly her back ... Marvelous advice - except it often does not work so simple !!

I'm lucky - I can fly basic quads and helicopters as well as fixed wing (over 50yrs of it) .... but many owners of DJI gear cannot. They have to rely on the autonomous functions ... something that I try and instill is to learn to FLY the machine without.

Nigel

 

[120CCPM]

People above post ... Oh just fly along the line and bring her back ! ... Switch to ATTI and just fly her back ... Marvelous advice - except it often does not work so simple !!
I'm lucky - I can fly basic quads and helicopters as well as fixed wing (over 50yrs of it) .... but many owners of DJI gear cannot. They have to rely on the autonomous functions ... something that I try and instill is to learn to FLY the machine without.

I assume you were referring to my post, but I'm not sure what's your point, though...
You say it's "marvelous advice" and "does not work so simple", then a couple lines below you basically repeat what I said, suggesting that people should learn to fly without autonomous functions.
Anyways, I stand by my comment: if the AC is flying erratically because of problems with GPS or compass, the last thing one should do is to engage RTH, as that's an autonomous flight mode that takes away control from the pilot and fully puts it on the very systems that are having trouble. Flying in A-Mode is something any drone pilot should practice and be able to do, even if in some conditions (e.g. outside VLOS) it might not be easy or even possible without some feedback from the AC (telemetry or video).

 

[Dazzauk]

Just a comment here: if you get "multiple warnings of strong magnetic interference",

Is this warning the same as strong interference? or different warning?

 

[Zorro54]

There is no way for the Phantom to return back to the home point when it automatically switches to ATTI mode. Instead, it'll auto land at its current location.

Can you turn the transmitter off to trigger Rth? I'm a newby..

Sent from my SM-G900V using PhantomPilots mobile app

 

[Dazzauk]

Can you turn the transmitter off to trigger Rth? I'm a newby..

Sent from my SM-G900V using PhantomPilots mobile app

I believe the only way for any phantom to return home is if it has gps signal. Otherwise it does not know where in the world in terms of co-ordinates it is.

Correct me if I'm wrong please.

Liken it to trying to navigate somewhere with a sat nav ( in car gps) without any satellites connecting to the unit. It would function.