Lost mine today, RTH failed.

[185EZ]

Thanks for everyone's replies.
Been taking note and need to do more reading of the manual.
I have an FC40 phantom and never had a problem and just ordered the Advanced.
Very excited but a bit nervous from reading some of the problems.
Carry on.

 

[Gary E]

I always have Trackimo on as a back up in case RTH fails.

And if you have no cell service, how is the Trackimo going to work? Marco Polo is a self contained tracker that does not need cell service. Hope I never have to use it on my craft.

 

[John Locke]

Every blue moon I'll get a brief compass error 80-100 up. It usually will go to ATTI, but I switch it there manually thereafter to bring it closer to me. In all cases it recovers on it's own and the MOD values all look normal. The only thing I can think of is flying over electrical wires. But I'm not really hovering near them, and we've seen videos of people flying quite close with no issues.

Hey, that happened to me last week, kinda freaked me out. I've got over a million feet of flight and that's the first time that had happen to me. I guess this was my "once in the blue moon" day. I was worried it was the 1.6 firmware, paranoia on my behalf. I immediately brought back the bird and landed it, thinking I had a problem, but maybe not. I had just flown 2 other batteries in the same spot with no problems or compass errors, then all of the sudden I have an error. I was about 300' away, 75' AGL, headed out on a fresh new battery on a mission when I got the error over a field of bushes, I'm nowhere close to transmission lines. I was at the beach miles from any buildings or homes. The only structures were restrooms about 50' away.

Anyway I re-calibrated and it flew OK with a green safe to fly confirmation.

 

[Ingsoc75]

And if you have no cell service, how is the Trackimo going to work? Marco Polo is a self contained tracker that does not need cell service. Hope I never have to use it on my craft.

If I go somewhere where mobile service may be unavailable I will keep that in mind.

But for 99.9999999% of the areas I do fly there is mobile service so Trackimo works for me.

 

[snowghost]

Hey, that happened to me last week, kinda freaked me out. I've got over a million feet of flight and that's the first time that had happen to me. I guess this was my "once in the blue moon" day. I was worried it was the 1.6 firmware, paranoia on my behalf. I immediately brought back the bird and landed it, thinking I had a problem, but maybe not. I had just flown 2 other batteries in the same spot with no problems or compass errors, then all of the sudden I have an error. I was about 300' away, 75' AGL, headed out on a fresh new battery on a mission when I got the error over a field of bushes, I'm nowhere close to transmission lines. I was at the beach miles from any buildings or homes. The only structures were restrooms about 50' away.

Anyway I re-calibrated and it flew OK with a green safe to fly confirmation.

Actually in my case, since the MOD values were all nominal, I didn't recalibrate and it hasn't happened since.

 

[droneshop]

Not sure how long everyone is waiting before taking off but you usually need to wait around 30 seconds or more to get the home point recorded message. if you loose GPS signal RTH will not work. your best bet is know where you are flying and switch to ATTI until GPS comes back online.

 

[Gary E]

If I go somewhere where mobile service may be unavailable I will keep that in mind.

But for 99.9999999% of the areas I do fly there is mobile service so Trackimo works for me.

Right on! You don't show where you are located. But you wouldn't find your craft in the western US states like Oregon, Washington, Nevada, Montana, Idaho, Utah, California, Colorado, Texas, Arizona, New Mexico, etc., etc., etc., etc.

 

[Martin&Di]

Regarding the compass questions posed in drones..... I realize it's needed, but nobody has provided a rational reason why a Phantom can't work like a Garmin handheld GPS device. Any little error and the craft is totally lame to find a couple of GPS coordinates (Home Point)? I have a Garmin handheld GPS unit I use in the desert and it never requires calibration. It's calibrated at the factory and I have never had recalibrate. I am puzzled how the Garmin can be accurate across the country, but it's always better than 25' accurate with 8+ satellites. So why are drone compasses so sensitive that with a 100mi movement they have to be recalibrated? I know logically calibrating every 100mi east or west would be more accurate, but even if it's off a couple degrees it should still be able to find a couple GPS coordinates, I would think. How does Garmin get around this? Is it because of their "automatic calibration"? Why can't DJI do the same? Our Phantom chooses to go whacky with the least little magnetic disturbance. I've never had a magnetic disturbance with my Garmin, has anyone else?

Here's the Garmin instructions to calibrate. The wording implies it won't need calibration, given their "automatic calibration" feature. And for me that's been true.

Calibrating the Compass
Your device was already calibrated at the factory, and the device uses automatic calibration by default. If you experience irregular compass behavior, for example, after moving long distances or after extreme temperature changes, you can manually calibrate the compass.

NOTICE! Calibrate the electronic compass outdoors. To improve heading accuracy, do not stand near objects that influence magnetic fields, such as vehicles, buildings, and overhead power lines.

1. Hold UP.
   
2. Select Settings > Sensors > Compass > Calibrate > Start.
3. Follow the on-screen instructions.

We are now drone owners, and we're so glad that we chose the Phantom 3 to start off with. Only flown it once so far, in a field in beginner mode. Loved it. But it's going to take a lot of practice in said same field before we venture further. All I wanted to say was firstly a BIG THANK YOU for this site/forum. I have read loads of very informative articles. And regarding the compass thing. I feel happier if I calibrated prior to every flight. But that's just me. As a newbie, but also as a pensioner. Check it once, then recheck.
Thanks again all of you experienced kind people.

 

[Meta4]

regarding the compass thing. I feel happier if I calibrated prior to every flight.

It's unnecessary to recalibrate the compass for each flight and it's due to poor wording or a bad translation that the idea caught on.
DJI have finally updated the wording in the manuals for their later models.
Rather than being a habit promoting flight safety, unnecessary recalibration of a perfectly good compass introduces the risk of a bad calibration which can lead to loss of your Phantom.
The basic principle to follow is to get a good calibration and stay with it.
You'll find a lot of compass info here: Compass Calibration, A Complete Primer

 

[Martin&Di]

It's unnecessary to recalibrate the compass for each flight and it's due to poor wording or a bad translation that the idea caught on.
DJI have finally updated the wording in the manuals for their later models.
Rather than being a habit promoting flight safety, unnecessary recalibration of a perfectly good compass introduces the risk of a bad calibration which can lead to loss of your Phantom.
The basic principle to follow is to get a good calibration and stay with it.
You'll find a lot of compass info here: Compass Calibration, A Complete Primer

I seriously cannot thank you enough for your kind advice.
It was a lot of money to us, So I'm over doing it in the must be as safe and responsible as humanly possible.
I understand a bit about the calibration and just want to learn more. I'm continuing to read and better read, as I'm not into making a fool of myself or causing any problems for others or us.
Thanks again for your kindness and information. With Regards.

 

[Neon Euc]

I seriously cannot thank you enough for your kind advice.
It was a lot of money to us, So I'm over doing it in the must be as safe and responsible as humanly possible.
I understand a bit about the calibration and just want to learn more. I'm continuing to read and better read, as I'm not into making a fool of myself or causing any problems for others or us.
Thanks again for your kindness and information. With Regards.

Recalibrating every flight is not necessary. They could be a time where you calibrate it next to something with a magnetic field and it will affect it. If it works once then you don't need to do it again unless you travel a few hundred miles from your original fly spot.

Imagine it like a computer. Every time you use your pc/laptop you don't install windows on it every time. It's the same principle here [emoji4]

 

[Richard R]

I seriously cannot thank you enough for your kind advice.
It was a lot of money to us, So I'm over doing it in the must be as safe and responsible as humanly possible.
I understand a bit about the calibration and just want to learn more. I'm continuing to read and better read, as I'm not into making a fool of myself or causing any problems for others or us.
Thanks again for your kindness and information. With Regards.

It may seem counter-intuitive, but the 'safe and responsible' approach is to NOT recalibrate each time! Take all the time you need in as clean an environment you can find and get a good calibration then leave it alone! Even if you get a warning when you go out into the field, try moving the bird first. Often the warning is an indication that there is something wrong with the location, not the compass. The compass is probably one of the most stable subsystems in your phantom and really never drifts or looses cal. I live in west central Ohio, have a pretty good idea what is and is not in the ground where I did my calibration and would be comfortable flying any where in continental US without doing another cal! One of my birds is over a year old and still works just fine on the initial calibration! Just like the pilot in a manned aircraft where the compass is calibrated once and the pilot never touches it (he does use the mag compass to periodically reset the gyro compass which does drift).

 

[John Locke]

I live in west central Ohio, have a pretty good idea what is and is not in the ground where I did my calibration and would be comfortable flying any where in continental US without doing another cal!

I think that's a stretch. I wouldn't recommend flying "anywhere in the US" on the same compass calibration, and I don't think many in this forum would either, regardless if it works most the time or not. I don't calibrate my compass much either, but if I'm more than 100mi east or west of my last calibration, I like to calibrate the compass.

 

[Meta4]

I think that's a stretch. I wouldn't recommend flying "anywhere in the US" on the same compass calibration, and I don't think many in this forum would either, regardless if it works most the time or not. I don't calibrate my compass much either, but if I'm more than 100mi east or west of my last calibration, I like to calibrate the compass.

I don't think it's a stretch at all.
DJI say nothing at all about calibrating if you travel 100 miles or any distance in their latest manuals.
I've experimented by flying 260 miles from home without recalibrating.
Then 430 miles, 1175 and finally 2265 miles from home and noticed no issues at all.
My P4 pro came from China and it's flown flawlessly straight-from-the-box without any compass calibration.
I'm convinced the whole 100 miles thing is a complete myth.

I cruised a yacht for 4 years back in a past life.
I fitted a new compass and had a licenced compass adjuster correct and compensate for the errors created by steel objects on the boat.
That's pretty well the analog version of what we do with a compass calibration.
After that, my compass was accurate anywhere in the world.
You don't hear of planes and boats needing to tinker with their compasses when they travel some distance from home.
Once your compass is good, it stays good.
When you calibrate it, you aren't doing any adjustment for your geographic location.
You are letting the compass know what magnetic influences it detects are due to the earth's magnetic field and what is part of the Phantom and caused by steel and/or electrical currents.

 

[John Locke]

I don't think it's a stretch at all.
DJI say nothing at all about calibrating if you travel 100 miles or any distance in their latest manuals.
I've experimented by flying 260 miles from home without recalibrating.
Then 430 miles, 1175 and finally 2265 miles from home and noticed no issues at all.
My P4 pro came from China and it's flown flawlessly straight-from-the-box without any compass calibration.
I'm convinced the whole 100 miles thing is a complete myth.

I cruised a yacht for 4 years back in a past life.
I fitted a new compass and had a licenced compass adjuster correct and compensate for the errors created by steel objects on the boat.
That's pretty well the analog version of what we do with a compass calibration.
After that, my compass was accurate anywhere in the world.
You don't hear of planes and boats needing to tinker with their compasses when they travel some distance from home.
Once your compass is good, it stays good.
When you calibrate it, you aren't doing any adjustment for your geographic location.
You are letting the compass know what magnetic influences it detects are due to the earth's magnetic field and what is part of the Phantom and caused by steel and/or electrical currents.

I agree, there's nothing that says to calibrate when moving any certain distance, however calibration is part of every drone, whether DJI, Yuneec or Autel. It's there for a reason. If one calibration was good anywhere, you shouldn't ever have to do it, and it wouldn't be part of the s/w app. So one has to decide, when do I calibrate? Sometimes the app will tell you to, and I believe that's based on location, assuming there's no magnetic anomaly at the launch site. That doesn't have often of course, and you can usually remove that warning my relocating the launch point 100' about 90% of the time. And if you don't move 100' to try and remove compass error first, and just calibrate there, you have a good chance of a bad calibration due to magnetic interference. So I never get in a hurry to recalibrate, just because I see a compass error during launch prep.

I have chosen 100 miles east or west to recalibrate, but that's me. You can take the risk of never calibrating, but I would lean more toward a routine of calibration when moving a distance, versus never calibrating as you suggest. My distance is 100mi because I don't move that far very often, so I seldom recalibrate.

I've had one compass error with my P3P, resulting in ATTI mode and the inability to enable RTH. The compass went wacky on the 3rd flight at the same spot, and that wasn't outside my 100mi rule, only 50mi. I never figured out why, but that's why I have my 100mi routine. With P4 and later craft I haven't had compass issues, I think due to the dual compass, that's my guess. I like my routine, and I feel it's safer, but neither of us have data to prove our cases either way. The fact that calibration is part of the software, and you're instructed to do it, means it's got to be done for a reason. The location is the only reasonable explanation I can think of, unless you have a more rational one.

 

[Meta4]

The fact that calibration is part of the software, and you're instructed to do it, means it's got to be done for a reason. The location is the only reasonable explanation I can think of, unless you have a more rational one.

It has nothing to do wth location.
If it did, you'd expect DJI to mention that in the manual - But they don't.
They don't even suggest you need to calibrate the Phantom before your first flight.
The calibration function is there so you can correct out any magnetic issues when you repair the Phantom or add electronc equipment or set up a new compass if you ever fit one.

 

[John Locke]

The calibration function is there so you can correct out any magnetic issues when you repair the Phantom or add electronc equipment or set up a new compass if you ever fit one.

Does it say that in the manual, or did DJI leave that out too? There's a lot of things left out of the manual. Does your insight come from DJI employees? Blade Strike or Tahoe Ed for instance? Just curious. Interesting thoughts.

 

[Meta4]

Does it say that in the manual, or did DJI leave that out too? There's a lot of things left out of the manual.

That's not in the manual - (it's very sparse) but makes sense.

Does your insight come from DJI employees? Blade Strike or Tahoe Ed for instance? Just curious.

No ... they aren't always a good source for tech details.

 

[John Locke]

That's not in the manual - (it's very sparse) but makes sense.

No ... they aren't always a good source for tech details.

Your conclusion is that because DJI left out the compass calibration protocol in the manual, you deem it unnecessary to recalibrate ever, right? Even though you admit the manual is sparse, which means they leave out helpful information, possibly compass calibration specifics. We all know DJI doesn't communicate well, agreed, so the absence of the calibration protocol in the manual doesn't surprise me, but I don't it's wise to use that omission to justify no calibrations.

Your compass protocol suggestions appears to be opinion, based on your other experiences, not data from DJI in any way. I assume you don't consider compass calibration protocols set by Yuneec and Autel as relevant either. And you don't believe prominent DJI employees (like BladeStrike or Tahoe Ed) either it appears.

In the P3P days conventional wisdom said to calibrate when the MOD values exceeded the 1400 to 1600 window. Are you saying that's wrong now? If you travel like I do, you know MOD values change beyond the recommended window when moving to locations far away, as little as 150mi, hence moving a few hundred miles usually always triggers P3P calibration. This experience in my past justifies calibrating when moving some distance, and my distance is 100mil.

Yes, I know the craft can fly OK sometimes when moving 1000mi away from last calibration, I've done that too, forgetting to calibrate. Others have said the craft flies crooked, as if the camera was skewed to the left or right. And, a compass calibration fix it, so they said. This could be another good reason to calibrate when moving a few hundred miles.

For the 60-90 seconds it takes to calibrate at a new distant location, I deem it good practice to calibrate if I move 100+mi away, assuming I remember , given the adrenaline of a new flight location . Calibrating that seldom doesn't increase my risk much IMO.

 

[Meta4]

Your conclusion is that because DJI left out the compass calibration protocol in the manual, you deem it unnecessary to recalibrate ever, right? Even though you admit the manual is sparse, which means they leave out helpful information, possibly compass calibration specifics. We all know DJI doesn't communicate well, agreed, so the absence of the calibration protocol in the manual doesn't surprise me, but I don't it's wise to use that omission to justify no calibrations.

Your compass protocol suggestions appears to be opinion, based on your other experiences, not data from DJI in any way.

My ideas about the compass are based on lots of flying over three years, an inquiring mind, a lifetime of compass experience, a science degree and 20 years as a professional scientist and the results of many other intelligent flyers.
It was worked out long ago that it is completely unnecessary to recalibrate every flight or new location.
DJI have finally changed the language in their latest manuals to reflect this.
DJI have never made any mention of 100 miles or any other distance. It's something made up by forum people and blindly accepted by many without any reasoning or testing.
Some users get a warm feeling from following rituals, thinking they are doing something to make them safer even though they have no understanding of what they are doing or the principles behind it.
Another word for that is superstition.
My understanding of the Phantom and it's system suggests that the 100 mile thing makes no sense, my testing confirms this and it fits with DJI's new compass text in the manuals.
That's good enough for me.

And you don't believe prominent DJI employees (like BladeStrike or Tahoe Ed) either it appears.

I've seen a number of times where they have given incorrect information. Often they are correct, sometimes they are not.

In the P3P days conventional wisdom said to calibrate when the MOD values exceeded the 1400 to 1600 window. Are you saying that's wrong now? If you travel like I do, you know MOD values change beyond the recommended window when moving to locations far away, as little as 150mi, hence moving a few hundred miles usually always triggers P3P calibration. This experience in my past justifies calibrating when moving some distance, and my distance is 100mil.

The mod value varies with what magnetic influences are nearby.
I suspect that proper testing would show that it doesn't vary with distance from a previous calibration point and that compass calibration has nothing to do with any geographic location.
In my testing I've never found anything to trigger a compass calibration at any distance except putting the Phantom down close to magnetic influences.
Compass calibration is all about eliminating magnetic and electromagnetic sources that are part of the Phantom so that it is only detecting the local geomagnetic environment.

Yes, I know the craft can fly OK sometimes when moving 1000mi away from last calibration, I've done that too, forgetting to calibrate. Others have said the craft flies crooked, as if the camera was skewed to the left or right. And, a compass calibration fix it, so they said. This could be another good reason to calibrate when moving a few hundred miles.

For the 60-90 seconds it takes to calibrate at a new distant location, I deem it good practice to calibrate if I move 100+mi away, assuming I remember , given the adrenaline of a new flight location . Calibrating that seldom doesn't increase my risk much IMO.

if my Phantoms wanted to fly a curved path rather than straight lines or exhibited slow spiraling when hovering, I'd do something about it.
But none have ever shown any of those tendencies.
Given the number of crashed or lost Phantom incidents I've investigated that begin with .. I calibrated the compass as I always do .....
...together with my experience and testing, combined with the results of many other flyers, I'd suggest that repeated compass calibration is unnecessary and increases the risk of getting a bad compass calibration with possible serious consequences.