What causes the Yaw error / Compass error?
I understand that a compass error occurs when the difference between Yaw and Magnetic Yaw is very large, right?
How big is this difference?

I tried examining some of the DATs here on the forum, in this case (taken from here https://forum.dji.com/forum.php? ... amp;fromuid=1065851)

at 312 the Yaw is 172 ° while MagYaw is -177 ° looks a big difference but in fact the difference is only 10 °, is it correct ?!



Same problem here at 312 the Yaw is 172 ° the MagYaw -171 ° = a difference of only 16 °



It looks like the system goes crazy when the Spark is between 170 ° and -170 °

Am I doing something wrong?
If you have any other DAT with Yaw error post it if you want

Thank you for analyzing my dat file . here is my tread with the more data https://forum.dji.com/forum.php? ... =1&extra=#pid979616 .The drone has not crashed when eror occured , i have continued to fly 6 minutes after error , and i flyed the second battery right after in same place .

You are welcome!
I'm trying to figure out if there is a common problem between the compass problems

Yes you are correct (note: 2nd picture you have a typo the 10 should be 16). No error at 20 & 19 but having errors at 10 & 16 is interesting. However the one thing that stands out is that the MagYaw line  should disappear at the top of the chart while appearing on the bottom but it does not always do that, the MagYaw lines are crossing the screen. Visualizing that it is rotating fully left and right without crossing the transition line, and it looks like it does that at the transition line only. So what this chart tells me is that system is measuring a yaw error of 344 degrees while in reality both points are only 10 or 16 degrees apart.
I have put the chart together in a different way to show what is happening.

Where these MagYaws oscillations come from is for DJI to explain as there is nothing in nature that could cause something like this. The only way to influence a compass this way is when a current passes and its passing quite frequently. But then going into the error and seeing a normal state after, and coming out of the error is like a mirror of the going in state it might just be that the algoritme or programming might need some debugging.

a little spark in Spark ?

Hecate Posted at 2017-9-30 10:34
Yes you are correct (note: 2nd picture you have a typo the 10 should be 16). No error at 20 & 19 but having errors at 10 & 16 is interesting. However the one thing that stands out is that the MagYaw line  should disappear at the top of the chart while appearing on the bottom but it does not always do that, the MagYaw lines are crossing the screen. Visualizing that it is rotating fully left and right without crossing the transition line, and it looks like it does that at the transition line only. So what this chart tells me is that system is measuring a yaw error of 344 degrees while in reality both points are only 10 or 16 degrees apart.
I have put the chart together in a different way to show what is happening.

Exactly!
From the chart it seems a big error while in reality are only 16 ° (you're right!) degrees of difference

And why Weak gps signal , gps health dropped from 5 to 0, but in dat file during the error period 19 satellites are still presents and coordinates are in good values ?  
https://forum.dji.com/forum.php? ... &fromuid=982278

djiuser_xLE6O03 Posted at 2017-10-1 01:36
And why Weak gps signal , gps health dropped from 5 to 0, but in dat file during the error period 19 satellites are still presents and coordinates are in good values ?  
https://forum.dji.com/forum.php?mod=redirect&goto=findpost&ptid=112713&pid=979616&fromuid=982278

Because when a compass error occurs, the system deliberately deactivates the GPS to be able to drive in ATTI mode
It's all right

Gps can be used without compass. If compass have error and is deactivated gps must remain activ , can be used for flying and rth.
I have flown Fpv  Rc AC at night based on osd gps display without compass on board from 10 years ago

Yes. A compass is needed to get the orientation before launching (if that is necessary at all)
When movement has started, the gps should not need the compass any more,

If compass error occur is a stupid thing to deactivate a working gps . It is the perfect recipe  for a fly away

I've always read that gps can not work without compass, if you say so then it does not make sense to disable gps  

Pirikitto Posted at 2017-10-1 04:42
I've always read that gps can not work without compass, if you say so then it does not make sense to disable gps

Gps can not work properly without compass no matter what above post tells you maybe in something as simple as a car it might, but not with a quad , gps needs to know where it is and where it’s going, Atti mode is the way to fly your AC when you lose or gps is dropped just because above posters can’t manage it doesn’t mean it can’t be done.

You keep repeating that. It's simply not true. GPS can and should work without a compass. It knows where it is, and if the AC initiates a short forward flight - GPS can also know where it's going via simple vector calculation. All it takes is to have that procedure in the firmware.
Then the AC, knowing its reference direction, can yaw toward the desired direction, presumably toward home. If an error has been introduced  during the initial orientation due to wind drift etc., do the procedure again after the first correction, and so on recursively. The error will decrease over time.
It may take some zigging and zagging, but it'll get to pretty much where it's supposed to go.

Here you go right from the AOPA 380029  Because when all is said and done, a GPS generates a latitude, longitude, altitude, direction, and speed. Aticle talks about integration of GPS for IFR and VFR

Gps itself does not need compass, but the drone needs to know which way it is facing so it can fly back to the desired GPS position. If the desired location is 5 meters away, it needs to know the direction the front of the drone is facing. So GPS mode does need a working compass to tell it that it needs to move 5 meters left, not right. Gps generates a direction/heading,
not the actual yaw position of te drone. The front can face the north, and if it drifts backwards the GLS will give south as the direction.

But why should the AC just let itself drift?
It can tell the difference between its nose and its tail, right?
So the AC should initiate a short forward flight, in the direction of the nose, whichever direction that is, while collecting GPS data. From multiple GPS points the AC can figure out its current heading, and it would know it's the same as its yaw position (because it knows it is flying head on), so the AC can now correct it.

djiuser_Kf4iPA3 Posted at 2017-10-3 14:49
But why should the AC just let itself drift?
It can tell the difference between its nose and its tail, right?
So the AC should initiate a short forward flight, in the direction of the nose, whichever direction that is, while collecting GPS data. From multiple GPS points the AC can figure out its current heading, and it would know it's the same as its yaw position (because it knows it is flying head on), so the AC can now correct it.

You could always open your spark and remove the compass and let us know how you get on flying without compass.

hallmark007 Posted at 2017-10-3 15:00
You could always open your spark and remove the compass and let us know how you get on flying without compass.

Yes, very clever answer......
I understand that right now that's how it's done - if compass gets lost, pretty much all nav systems  get lost and you go to ATTI mode. I don't dispute that's how things are now. Doesn't mean I accept the logic of that, because GPS is data is still there and it can be used.
The procedure I'm offering would work if it were part of the AC's firmware, and it should be, because GPS has that capability, and it's more reliable and more robust than a compass.

As a programmer/application developer (now a manager, so I've lost some IQ), I performed a thought experiment on how I as a developer would try and design software to fly only with GPS and no compass.  There's some challenges that I thought of, and not sure how they could be overcome except with a lot of CPU.  Suppose we have a craft with no compass data.  Suppose it's facing "north".  It doesn't know it's facing "north".  If it flies forward and detects a delta of movement to the north, it then can extrapolate that it's facing north.  EXCEPT:  suppose there's a force applied to it of 6mph winds to the east, and it attempts to propel itself 6mph forward (which happens to be) to the north.  It will travel NE.  We still can't rely or extrapolate on which direction it's facing.  Based on this delta, what the craft knows is that it went forward and traveled NE, and could extrapolate that it's facing NE when in fact it was facing N.  In order to make a determination as to the direction it's facing the craft would have to perform a series of movements in various directions and compare the deltas to determine which direction it's facing and the environment impacts in force upon it.  And if those environment impacts are not consistent (swirling wind), there's additional challenges.  The craft would always need to be in a state of constant "calibration" to adjust for changes to the environment.

It would be a computational challenge.  Not saying I couldn't do it, but that's a lot of data crunching.

yes, but if you do it recursively your error will decrease over time and over each iteration of flight-calculation-yawing. Even if the wind changes you would still be able to correct yourself. It ain't going to be a pretty flight, you will zig and zag, but you will converge toward your general direction after a few corrections.
Even if you don't hit home on the spot, you will have brought the craft closer to it and to its pilot. PLUS, you have GPS readings available all the way; even if worse comes to worst and you don't make it home and crash, you do it with updated GPS and at closer proximity to the pilot - making the search for the craft much easier.
It's definitely better than just letting the craft drift randomly and blindly.

Also, to add, my suggested algorithm is a little different. Let's use your numbers as an example.
For the sake of the discussion, let's suppose home is to the south (azimuth 180 deg) of where the craft is - but you can put any direction here and re-do the math.
The craft is facing north (0 deg) and moves forward. With the wind factor, it actually travels NE (45 deg), and that's where it thinks it's facing. It yaws 135 degrees to the right, thinking it has now faced itself south. But it has a 45 degree error (plus-minus some extra error picked up while yawing), however that's already in much better shape than the complete blindness it was in before. It actually faces SE (azimuth 135 deg) now.
2nd iteration - now it travels 6MPH facing SE, initially thinking it's facing south. In fact, the 6MPH wind factor will push it further to the east. If I've done my vector calculation correctly (haven't done it in a while...) then in fact the drone travels toward azimuth 112. The drone finds that out via GPS collection and vector calculation, and determines it has to yaw 68 degrees to the right to face south.
But in fact, its nose was facing toward 135. So an addition of 68 degrees will make it overshoot the south and face toward 203 deg. But hey, that's much closer to 180 now. The error has decreased to 23 degrees.

And so on and so forth, keep doing that in an iterative fashion.
If the wind changes you may need extra iterations, or replace the simple vector calculation with some (not too complicated) statistical calculation. But it's doable, and it converges.

My intuition is it would also not require as much CPU as you think, but if you need extra CPU/memory/etc. - you can kill some non-vital tasks to free up resources. After all, you are in an emergency, and your primary mission now is to get the craft home and save it.

djiuser_Kf4iPA3 Posted at 2017-10-9 04:44
yes, but if you do it recursively your error will decrease over time and over each iteration of flight-calculation-yawing. Even if the wind changes you would still be able to correct yourself. It ain't going to be a pretty flight, you will zig and zag, but you will converge toward your general direction after a few corrections.
Even if you don't hit home on the spot, you will have brought the craft closer to it and to its pilot. PLUS, you have GPS readings available all the way; even if worse comes to worst and you don't make it home and crash, you do it with updated GPS and at closer proximity to the pilot - making the search for the craft much easier.
It's definitely better than just letting the craft drift randomly and blindly.

I think you miss the point completely when AC drops gps it automatically goes to Atti mode this is fully controllable as we have seen with many here , it doesn’t just fly all over the place it only flys one way downwind, so all you need is to know which way the wind is blowing .what you are suggesting appears to be just as difficult if not more difficult to control , yes we may see the day when there are improvements as we know Chinese are already involved in Compass Navigation Satellite System.
But until you try out your theory or system , it’s just speculation , it maybe mathematically possible , but it’s only pie in the sky until it’s seen to be working.

really interesting post. im going to follow this.  

i just want to add that both sides are right about this GPS thing, technically speaking, GPS is still functional system as a standalone thing without a compass,however it is fairly "useless" system in short duration that would be used with these drones.  this is because for a GPS to find direction (this is over simplifying it by alot) it requires longer range of use. think about it like this, you're using a physical paper map and no compass, and tracking something, you have to set up pinpoints of where you passed and current are at on coordinates and make a line to form a good sense of direction, and even so, that line is far from absolute, much the same here with a GPS not connected to a compass.. just like that line being formed, any deviation off that course is hard to spot until much later and thus fairly wasteful.   

i however do agree that it is stupid dji semi disables GPS on lost compass...  because even without compass, a solid GPS lock and do a decent job at position holding specially with aid of  cameras and IMUs..

You don't get it, do you...
What I'm suggesting is not controlled flight, it's an autonomous return-to-home procedure in case of compass failure. The aim is to get the aircraft home, with as little margin of user error as possible in sub-optimal conditions.
Not everyone is as good a pilot as you and not everyone feels comfortable with ATTI mode. And if a compass error happens at the edge of your control range - which in Europe is not that far - and the wind happens to be blowing away from you, even LOS and your skills won't save you. Your drone is likely kaput.

That's the whole point - in an emergency, leave as little room for user error as possible, and make life easier even to the less experienced and less confident. I mean, with your logic, why have a return-to-home button at all? Let the pilot guide the drone home in all emergencies.
You can call it "speculation" all you like, I don't care. it's based on my knowledge of the technologies involved, and their capabilities - it's not a guess. and I haven't seen you show the technical knowledge of these technologies to grade my procedure. the other choice is to let drones of pilots not as good or experienced as yourself fly away in an emergency, as if that's inevitable destiny. it's not.
And letting the technology that's most sensitive and prone to interference overrule the system that's much more robust and reliable - that doesn't make even the slightest technical sense.

HereForTheBeer Posted at 2017-10-9 06:48
really interesting post. im going to follow this.  

i just want to add that both sides are right about this GPS thing, technically speaking, GPS is still functional system as a standalone thing without a compass,however it is fairly "useless" system in short duration that would be used with these drones.  this is because for a GPS to find direction (this is over simplifying it by alot) it requires longer range of use. think about it like this, you're using a physical paper map and no compass, and tracking something, you have to set up pinpoints of where you passed and current are at on coordinates and make a line to form a good sense of direction, and even so, that line is far from absolute, much the same here with a GPS not connected to a compass.. just like that line being formed, any deviation off that course is hard to spot until much later and thus fairly wasteful.   

Sorry, my last remark was not to you.
Regarding what you said, yes, errors will occur when you start the procedure. But what I'm suggesting here is an iterative procedure, not a one-shot. As I have shown in my example, over time and iterations the error will decrease. I don;t suggest collecting just two points in each iteration either - collect enough to make your collection statistically viable and reduce your error.
GPS is much more accurate than a line drawn on a map with a pencil. And when you take several points and perform a vector calculation, even more so - because much of the GPS error is the same for those points, so when performing vector calculation many of the errors of individual coordinates cancel out each other.

djiuser_Kf4iPA3 Posted at 2017-10-9 07:03
Sorry, my last remark was not to you.
Regarding what you said, yes, errors will occur when you start the procedure. But what I'm suggesting here is an iterative procedure, not a one-shot. As I have shown in my example, over time and iterations the error will decrease. I don;t suggest collecting just two points in each iteration either - collect enough to make your collection statistically viable and reduce your error.
GPS is much more accurate than a line drawn on a map with a pencil. And when you take several points and perform a vector calculation, even more so - because much of the GPS error is the same for those points, so when performing vector calculation many of the errors of individual coordinates cancel out each other.

no you are right, i was overly simplifying it for everyone else on the outside of basic understanding.  

but issue is short duration, on a RTH you need heading data asap and need it as accurate as possible, that's typically why without a compass a GPS seems fairly useless in most basic applications, sadly also seems to include this.  

Two points to that:
One, I think you are underestimating the capabilities of GPS. These days, for example, athletes such as soccer players wear GPS vests that accurately measure the distance and directions they run during a game - and that is measured on much shorter ranges.
Two, like i said, I don't expect it to behave as regular RTH. It can't. It'll be an ugly, zigzagging flight - but as my example shows, over time and iterations it will converge to the right direction. Anyway, even if it's only close to it, it's much better than blind drifting with the wind and having the pilot try to manually recover in ATTI mode.

djiuser_Kf4iPA3 Posted at 2017-10-9 07:17
Two points to that:
One, I think you are underestimating the capabilities of GPS. These days, for example, athletes such as soccer players wear GPS vests that accurately measure the distance and directions they run during a game - and that is measured on much shorter ranges.
Two, like i said, I don't expect it to behave as regular RTH. It can't. It'll be an ugly, zigzagging flight - but as my example shows, over time and iterations it will converge to the right direction. Anyway, even if it's only close to it, it's much better than blind drifting with the wind and having the pilot try to manually recover in ATTI mode.

all the better if Dji can stop ignoring data that exists and is being pipped in by multiple sats, i agree.   hell even if it used that data to position hold it and resets the compass or reboots it...or something.. even that is miles better than letting the drone just, fly away because of bad programming.

djiuser_Kf4iPA3 Posted at 2017-10-9 06:51
You don't get it, do you...
What I'm suggesting is not controlled flight, it's an autonomous return-to-home procedure in case of compass failure. The aim is to get the aircraft home, with as little margin of user error as possible in sub-optimal conditions.
Not everyone is as good a pilot as you and not everyone feels comfortable with ATTI mode. And if a compass error happens at the edge of your control range - which in Europe is not that far - and the wind happens to be blowing away from you, even LOS and your skills won't save you. Your drone is likely kaput.

Ok first let’s get things into perspective here, what you are suggesting is not available in dji drones that’s the first thing, your system is also not available in any other SUA’s, in fact apart from what’s in your head this system has never been tried or tested, so it doesn’t matter what you think your system does it has never done ,  and until it is it just remains your theory. Putting something on paper means dlddly squat until it’s tried and tested and it hasn’t.

As someone who has built many small quads and been around them for quite awhile, I fully understand the mechanics of how they work, and while I don’t profess to be an expert like you on all the technology, and I am very pragmatic and practical in my view. I do know what you are saying is only theory and theory never made anything work on its own.

And BTW in an emergency it’s not the job of pilot or AC to return home , it’s the job of the pilot to land the AC ASAP and as safe as possible.

hallmark007 Posted at 2017-10-9 07:26
Ok first let’s get things into perspective here, what you are suggesting is not available in dji drones that’s the first thing, your system is also not available in any other SUA’s, in fact apart from what’s in your head this system has never been tried or tested, so it doesn’t matter what you think your system does it has never done ,  and until it is it just remains your theory. Putting something on paper means dlddly squat until it’s tried and tested and it hasn’t.

As someone who has built many small quads and been around them for quite awhile, I fully understand the mechanics of how they work, and while I don’t profess to be an expert like you on all the technology, and I am very pragmatic and practical in my view. I do know what you are saying is only theory and theory never made anything work on its own.

Good idea, let's get some perspective here. Offering a viable procedure, based on technical knowledge and reasoning, is worth diddly squat; but ruling it out right off the bat, without any technical reasoning or merit - that's worth so much more! yeah, in fact, saying "not possible" without any reasoning is the attitude that has progressed humankind through the ages. Commendable!

Yes, it's a theory. every development starts with a theory. But it's not a guess like you try pointlessly to present it. It's a theory based on knowledge of the technology, its capabilities and its potential. Which is more than you can say when you disqualify it with no merit whatsoever.
Granted, I can't test it, I don't build drones and don't write drone firmware. But DJI does. My procedure would improve their product, raise its accessibility and improve the confidence of at least the more novice users; if my theory is no good, they (or anyone else) can come here and tell me why. Why it makes sense that the most sensitive apparatus should knock away the data of a much better system. Why the terrible procedure in place today is optimal and there's no going beyond it.
If you demand users to test every improvement they offer - as in, build and program it themselves - what's the point of having this forum anyway?

The others who have challenged my procedure have at least done so with reasoning. They pointed out possible technical difficulties that made sense, and i replied with technical ways to overcome of mitigate their effect. emphasis on "technical".
You do nothing of the sort. Your only reasoning is "they don't do it today, so it's impossible". You're the zealot waving a cross at my face yelling "blasphemy!"

and as for your BTW point - based on that logic, I suppose you suggest to abolish emergency RTH altogether then...

djiuser_Kf4iPA3 Posted at 2017-10-9 09:36
Good idea, let's get some perspective here. Offering a viable procedure, based on technical knowledge and reasoning, is worth diddly squat; but ruling it out right off the bat, without any technical reasoning or merit - that's worth so much more! yeah, in fact, saying "not possible" without any reasoning is the attitude that has progressed humankind through the ages. Commendable!

Yes, it's a theory. every development starts with a theory. But it's not a guess like you try pointlessly to present it. It's a theory based on knowledge of the technology, its capabilities and its potential. Which is more than you can say when you disqualify it with no merit whatsoever.

I suppose when others more qualified offered why your idea would not be possible you also refused to take that on board, it seems that everyone who disagreed with your theory is wrong.

You keep putting this theory forward as a safety measure, yet you are at the same time trying to find out if it’s safe to fly a drone out of a window and back in , which is very confusing because this is one of the most unsafe things you can do with a drone, yet you complain about the terrible procedure in place in dji drones today, hypocritical to say the least.

As someone who is interested in all things aeronautical I realize flying AC manned or unmanned depend on as many redundancies as is possible and this has been the way since the birth of aerial flying,  so with regards to RTH this has been one of the most important redundancies to be added to all new dji SUA’s and I look forward to every new redundancy that comes on board.

You are the one who is on almost every thread spouting your untested theory which many find not plausible and reasons why have already been pointed out to you, you don’t accept any of these that’s your opinion and I’m entitled to mine.

While you say gps is a better apparatus than compass, you won’t see any aircraft manned or unmanned and ship sailing boat and many other vehicles without compass it’s been around since god was a boy and I don’t see it being made redundant anytime soon.

Regarding you religious quote, go join the god forum.

Let's start by saying that I never discussed flying the aircraft out of a window. I asked whether i can fly it out of an open-air balcony, which is totally different. And even in that thread I wouldn't agree to suggestions that seemed too unsafe to me. But this isn't the first time you don't actually read what you're commenting to, so I don't expect an apology for calling me names with no basis except you not understanding what you're reading.

Yes, others have challenged my procedure, but unlike you they did it with reasoning - and got replies as to why my procedure can overcome or mitigate the effects of the difficulties they presented. That kind of discussion is fruitful and I welcome it, I'm happy to have that kind of discussion any time. But so far nobody has presented a difficulty that was uncovered by my procedure.

You talk about the need for RTH and the need for redundancy, I agree, redundancy is very important. My procedure enhances RTH to cover one more very important scenario, and enhances redundancy. And yet you insist, based on nothing at all, that it makes sense that the most sensitive navigational system should knock out the data from ALL navigational systems, including at least one system that is more reliable and more robust. Where's the redundancy there? there's no redundancy at all. It's a terrible procedure with a bad outcome, and yet you hang on to it tooth and nail with no reasoning at all.

And you seem to think, based on your penultimate paragraph, that I suggest to throw away the compass altogether. I don't and I never did. If you actually thought I did, that's another one of your misreads.
If the compass works, it's useful and should be used. But sometimes, it just doesn't... and you think that without the compass everything else must fail, and the potential of other technologies that already exist on the drone to overcome the lack of compass should be ignored. So much for the importance of redundancy...

Regarding the last quote - nothing I can do about that. When you come with no technical reasoning, and all you say can be summed up in "that's how they do it now, so that's the way it must be done and how dare you doubt that" - that's how it feels. Sorry.

djiuser_Kf4iPA3 Posted at 2017-10-9 11:02
Let's start by saying that I never discussed flying the aircraft out of a window. I asked whether i can fly it out of an open-air balcony, which is totally different. And even in that thread I wouldn't agree to suggestions that seemed too unsafe to me. But this isn't the first time you don't actually read what you're commenting to, so I don't expect an apology for calling me names with no basis except you not understanding what you're reading.

Yes, others have challenged my procedure, but unlike you they did it with reasoning - and got replies as to why my procedure can overcome or mitigate the effects of the difficulties they presented. That kind of discussion is fruitful and I welcome it, I'm happy to have that kind of discussion any time. But so far nobody has presented a difficulty that was uncovered by my procedure.

Your offering up a theory for what might happen when you have a compass problem, so what is your offering for when you lose gps which is much more common than compass problem. And while the pilot has some control over making sure he has a compass in working order he has no control for when loosing gps.
So tell us how do you solve the problem of loosing gps?

Oh changed the subject now have we? That's an entirely different subject now. And a much tougher one, in my view.
But I'll indulge you.
Let's start by saying that I hope you don't condone throwing away data from other navigation systems...

Are we talking about loss due to being obscured from the sky? or the craft is seeing satellites and not being able to acquire GPS?

hallmark007 Posted at 2017-10-9 11:31
Your offering up a theory for what might happen when you have a compass problem, so what is your offering for when you lose gps which is much more common than compass problem. And while the pilot has some control over making sure he has a compass in working order he has no control for when loosing gps.
So tell us how do you solve the problem of loosing gps?

I'd like to see an option for ATTI mode as seen on the Phantom line up. No idea why this was removed on the Mavic and Spark. Hopefully we'll see this added in future FW. It will surely help practice scenarios when GPS is lost and the AC switches to ATTI.

djiuser_Kf4iPA3 Posted at 2017-10-9 11:52
Oh changed the subject now have we? That's an entirely different subject now. And a much tougher one, in my view.
But I'll indulge you.
Let's start by saying that I hope you don't condone throwing away data from other navigation systems...

Look this is my last post to you, and while technology is not my strongest subject I will explain why your theories won’t work.

It seems simple but look at it this way:

You're blindfolded standing on a Segway in the middle of a dynamic obstacle course. You've got a group of 12 people standing around you to give you verbal directions on which way to go. Some of them see you clearly while some see a blurry version and some may be looking at you via mirrors etc. All of them are yelling at you turn left, turn right, speed up, slow down, back up.... You're trying to listen to everyone while navigating an obstacle course that is constantly moving around you. You have to calculate which ones are collectively telling you correct info and which ones to disregard. All while someone else is remotely trying to drive your Segway.

All of this is done "behind the curtain" while we are trying to learn to fly and not crash into things

Sorry, but your excuse for a fable is not related to the issue we've been discussing in any way shape or form.
In reality, it's the AC itself telling you which system is wrong - the compass. The whole thing starts with a "compass error". our issue is that GPS still works properly. You don't have to listen to 12 systems to replace the lost compass in telling your direction; just GPS. Doing something well within its capabilities.
If all you have left to contribute the discussion is unrelated fables, perhaps it's a good thing this is your last message in it. Leave the fables to Krylov or La Fontaine.

djiuser_Kf4iPA3 Posted at 2017-10-9 12:37
Sorry, but your excuse for a fable is not related to the issue we've been discussing in any way shape or form.
In reality, it's the AC itself telling you which system is wrong - the compass. The whole thing starts with a "compass error". our issue is that GPS still works properly. You don't have to listen to 12 systems to replace the lost compass in telling your direction; just GPS. Doing something well within its capabilities.
If all you have left to contribute the discussion is unrelated fables, perhaps it's a good thing this is your last message in it. Leave the fables to Krylov or La Fontaine.

I was right about nobody knows more than you, I’m glad I confused you you are just a narcissist.

The compass tells the drone which direction it's facing. The GPS data is used to find the latitude/longitude location.
Bear in mind that in a fluid such as air, Course (path across ground) and Heading (direction nose is pointed) are often different. Only in dead calm conditions would they be the same.
Same as a boat subject to the water currents or a car '

GPS only knows direction if it is moving. Take a handheld GPS and stop. You can turn the GPS and it will only display the proper direction after you start moving again. You need a compass to know what direction you are facing if you aren't moving.

And if you want anymore explanations. I can give you 10 more.