Lost mine today, RTH failed.

The problem with the suggestions to not recalibrate the compass is, when the app gives a compass error your choices are to recalibrate or not fly because it won't allow the motors to start until a successful recalibration is complete. Unfortunately this happened so often for me I considered it routine. It now seems to me that the app could be better designed by providing a "magnetic interference" warning instead of simply prompting to recalibrate. IMHO

Other than calibration, you have to choose the right take off point. If you're getting an error on a good calibration before take off, you're trying to take off in the wrong spot. If you're getting an error in the air, either your calibration is bad or you're close to a significant source of interference.
 
The problem with the suggestions to not recalibrate the compass is, when the app gives a compass error your choices are to recalibrate or not fly because it won't allow the motors to start until a successful recalibration is complete. Unfortunately this happened so often for me I considered it routine. It now seems to me that the app could be better designed by providing a "magnetic interference" warning instead of simply prompting to recalibrate. IMHO
The app does indeed warn you. Try and launch the quad from the hood of your car.....
 
The problem with the suggestions to not recalibrate the compass is, when the app gives a compass error your choices are to recalibrate or not fly because it won't allow the motors to start until a successful recalibration is complete. Unfortunately this happened so often for me I considered it routine. It now seems to me that the app could be better designed by providing a "magnetic interference" warning instead of simply prompting to recalibrate. IMHO
You are correct - DJI could word the notification better.
Too many people think Compass Error means there is something wrong with the compass and that calibration will fix it.
When actually the compass is fine but it's advising it has detected a magnetic field problem that needs fixing (usually by moving to a safer location)
 
I undestood what you said - hence my reply.

What I don't understand is "why?". Read my post again carefully and answer the questions in there.

If you believe you should always be able to see your quad the you really wasted a lot of money on your P3. A much better buy would have been a Solo or Blade with a half mile Wifi range.
I'm just saying. if I am flying with less than optimal conditions, or terrain than I 'm going to keep it insight per se.
 
You are correct - DJI could word the notification better.
Too many people think Compass Error means there is something wrong with the compass and that calibration will fix it.
When actually the compass is fine but it's advising it has detected a magnetic field problem that needs fixing (usually by moving to a safer location)
This is enlightening. I assumed if there is a compass error there was something wrong with the craft. It never dawned on me it could be the area, especially if I'm 50' high and over beach bushes, 150' horizontally from anything man-made. My "compass error" incident Monday happened with a good compass calibration, I had flown it about ten times since loading 1.6 when I calibrated the imu and compass just 15 miles away in an open field by my house. And on Monday I flew from the same spot an hour earlier with no problem. I kinda panicked because I had never had a compass error mid flight like that, only seconds after departing on the mission, so I didn't try continuing the flight, came right back too recalibrate. I'm unsure what caused my anomaly but it was a total surprise. I'm definitely going to calibrate the compass again before I fly next. I don't trust that asphalt calibration I did on Monday.



Sent from my iPad using PhantomPilots mobile app
 
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JKDSensei, thank you for asserting that I don't know what I'm doing, same goes for the moderator. No, I did not get it for Christmas and fly it right out of the box. I "brushed up" my knowledge quite a bit as I have been flying this thing for months quite successfully. Prior to ever flying it I watched every DJI video repeatedly, spent hours on the flight simulator, and have been enhancing my knowledge by reading this forum. I had come to fully trust RTH to bring it back to the area but don't allow it to auto-land per the drift of up to 12 feet in the landing point I mentioned in an earlier post.

Prior to this flight I was prompted to calibrate the compass. I was atop a parking structure so I suspected rebar in the concrete might have been a problem, on the third attempt it was successful, the error cleared and allowed the motors to start. I previously manually changed RTH altitude to 90 meters (high enough to clear any objects in the area), and had the green "safe to fly GPS mode" indicator on the app, steady green rear arm lights, and a verbal "return to home location set" notification.

During this flight RTH engaged once and worked fine. Once it was nearby I cancelled RTH and continued to fly. The second time RTH engaged I was near a tall building. It is very possible that the antenna array atop that building could have caused signal interference. So, if that is the case, is fly off a likely outcome, and could interference be the cause for the RTH fail?

Yes and yes.

No problem. Now that you took out much of what you originally posted (and added a lot more), it comes across differently. Before you heavily edited your posts you did sound like you didn't know what you were doing. Sorry, but it sounded that way as first posted. That was neither my fault nor the moderator's that you mentioned. Glad you changed it so your true knowledge is more apparent.

Another thing that can affect this is transmission towers. I have been as far as a mile away and have taken hits that caused me to lose connection. Some of those transmissions are highly directional and are concentrated into relatively narrow beams. But they all have one thing in common...they are EMF....Electro MAGNETIC Fields. And can affect the compass and GPS.
 
Yes and yes.
......
Another thing that can affect this is transmission towers. I have been as far as a mile away and have taken hits that caused me to lose connection. Some of those transmissions are highly directional and are concentrated into relatively narrow beams. But they all have one thing in common...they are EMF....Electro MAGNETIC Fields. And can affect the compass and GPS.
The only way that EMF could have an effect on a compass is if the frequency of the EMF is lower than the frequency response of the compass. Typically compasses have a frequency response around 25 Hz which is way below the 50 or 60 Hz EMF coming from a transmission line. If 60 Hz energy got coupled into the compass it would be evident in the compass data. At my location I routinely fly over some transmission towers and have never seen any indication of a 60 Hz signal in the compass data. The EMF coming from the corona discharge is even a higher frequency and even more impossible to cause compass errors.

Geomagnetic distortion caused by close proximity to the lines is probably not an issue either because they are usually made of aluminum. If they are steel re-enforced my sense is the P3 would have to be no further than 10 or 20 feet for it to be a problem. Towers should be avoided.

The real issue with transmission lines is the RF energy caused by any corona discharge which interferes with the receiver part of the GPS. Typically, this RF energy is small at GPS frequencies but if close enough can be a problem. When you say that you've had a problem at one mile I'm assuming that you meant the you and the controller are one mile away from the P3 which is close to the transmission lines. I'd find it very hard to believe there could be a GPS problem in a P3 one mile from a transmission line.
 
Other than calibration, you have to choose the right take off point. If you're getting an error on a good calibration before take off, you're trying to take off in the wrong spot. If you're getting an error in the air, either your calibration is bad or you're close to a significant source of interference.

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 its 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.
 
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The only way that EMF could have an effect on a compass is if the frequency of the EMF is lower than the frequency response of the compass. Typically compasses have a frequency response around 25 Hz which is way below the 50 or 60 Hz EMF coming from a transmission line. If 60 Hz energy got coupled into the compass it would be evident in the compass data. At my location I routinely fly over some transmission towers and have never seen any indication of a 60 Hz signal in the compass data. The EMF coming from the corona discharge is even a higher frequency and even more impossible to cause compass errors.

Geomagnetic distortion caused by close proximity to the lines is probably not an issue either because they are usually made of aluminum. If they are steel re-enforced my sense is the P3 would have to be no further than 10 or 20 feet for it to be a problem. Towers should be avoided.

The real issue with transmission lines is the RF energy caused by any corona discharge which interferes with the receiver part of the GPS. Typically, this RF energy is small at GPS frequencies but if close enough can be a problem. When you say that you've had a problem at one mile I'm assuming that you meant the you and the controller are one mile away from the P3 which is close to the transmission lines. I'd find it very hard to believe there could be a GPS problem in a P3 one mile from a transmission line.

Thanks Bud, excellent info. It wasn't transmission lines....it's a transmission tower and very repeatable. Goes nuts at the same altitude every time. Lost signal etc. Since I'm not an electrical engineer I assumed it was a very strong, very directional transmission from that tower and I was in the direct path of some powerful EMF transmission.....microwave etc.

The amount of knowledge available at this place is amazing.
 
Electrical wires can cause issues but they really have to be very high current to be noticeable. I flew at the LA river earlier this week. It's a jungle gym of 300KV regional distribution pylons and power lines. My MOD values were down to 800 in some places. It was scary but I had the finger on the ATTI switch ready to dump GPS at the first sign of trouble. It did get squirrelly a few times. The drone will twitch once in a while which means you're very close to having it go bezerk.

Normal local power lines are no issue. As long as you don't hit them!

The other week, I shot a commercial on a bridge above the LA river. Power lines galore. I was operating the X5 gimbal while my associate flew the Inspire. He had it go full tilt away from us twice as result of compass interference. He wrestled it back. We reset and tried again. Scary watching $6,000 try to kill itself!
 
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Yes and yes.

No problem. Now that you took out much of what you originally posted (and added a lot more), it comes across differently. Before you heavily edited your posts you did sound like you didn't know what you were doing. Sorry, but it sounded that way as first posted. That was neither my fault nor the moderator's that you mentioned. Glad you changed it so your true knowledge is more apparent.

Another thing that can affect this is transmission towers. I have been as far as a mile away and have taken hits that caused me to lose connection. Some of those transmissions are highly directional and are concentrated into relatively narrow beams. But they all have one thing in common...they are EMF....Electro MAGNETIC Fields. And can affect the compass and GPS.
I have not edited any of my posts in any way. Perhaps your comprehension was not properly calibrated. :)
 
I've lost signal in the past and it always returned. Same thing this time only it didn't come back. I calibrated the compass and had a green "safe to fly GPS mode" prior to takeoff. Rhoffart, It is my understanding that RTH is for when the controller loses communication with the craft.
you must not have set your home point did you recover your craft if so and you need it fixed call ALLTRONIX AT260-489-6892
 
I was referring to no one's post. Just a bit of general advice for the masses. I'm sure there are many of our new members who know their stuff.
There are definitely some of us noobs that have done a lot of reading. How new to the forum doesnt have to correlate with knowledge
 
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A small investment in a seperate gps system is a small price to pay compared to cost of Phantom 3. Why risk it. Trackimo is a great product and gives you peace of mind.
 
guys, I had a few days ago more or less the same issue : after 10 minutes flying I hovered the Phantom to think what I could manouvre next. Suddenly the Phantom started slowly landing.
Battery at 16%, distance 10 meters, hight 5 meters. Enough for 2 times RTH. The App showed me : communication loss. Took about 10 minutes to recover a communication. Around 200 Meters circle were no metall or radio equipments. The day before I did a RTH manually and automaticaly, as I am a newbee and have to train and get used to these things.
Nothing in my mind I made wrong. But that the Phantom did not made a RTH this time broke my trust.
I am living on an island. So I will fly very often over water. If the Phantom would have landed in water.... Landing right there, automatically could be fatal. So why not hovering until it gets communication again ? Yes crashing in a worse place after the battery is empty could happen, but there is a bigger chance to get communication back !
 
guys, I had a few days ago more or less the same issue : after 10 minutes flying I hovered the Phantom to think what I could manouvre next. Suddenly the Phantom started slowly landing.
Battery at 16%, distance 10 meters, hight 5 meters. Enough for 2 times RTH. The App showed me : communication loss. Took about 10 minutes to recover a communication. Around 200 Meters circle were no metall or radio equipments. The day before I did a RTH manually and automaticaly, as I am a newbee and have to train and get used to these things.
Nothing in my mind I made wrong. But that the Phantom did not made a RTH this time broke my trust.
I am living on an island. So I will fly very often over water. If the Phantom would have landed in water.... Landing right there, automatically could be fatal. So why not hovering until it gets communication again ? Yes crashing in a worse place after the battery is empty could happen, but there is a bigger chance to get communication back !
I think if you are near your quad when rth initiates it just lands. Not sure of the default distance. I think thats what happened, or maybe Im misunderstanding.

edit: I believe you can change the setting to hover instead of return to home. But you cant have both :D
 
From what I've read you need to do a compass calibration before every flight to be safe. You also want to make sure the rth attitude is set to clear any obstacles on the way back. RTH does not bring it in to where you took off from if it's within 30 meters it just lands where it is. Hopefully someone more knowledgeable can chime in.
You Read wrong, no where in the many does it state to calibrate compus before each flight, very misleading information that can cause more issues!
 
Androne,

Did you upload the flight data to healthydrones.com to analyze it? That is the first thing I would start with. It shows the path your Drone took until signal was lost and the strength of the GPS signal. It even shows the number of satellites being picked up. For example:
gps.png


Red is bad, orange is good. You need to look at your flight data and see the GPS data.

My guess is you encountered a loss of controller signal at the same time there was a GPS loss. The Drone would not be able to RTH at this point. It would eventually land right below this last location.
 
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I think if you are near your quad when rth initiates it just lands. Not sure of the default distance. I think thats what happened, or maybe Im misunderstanding.

edit: I believe you can change the setting to hover instead of return to home. But you cant have both :D

Androne,

Did you upload the flight data to healthydrones.com to analyze it? That is the first thing I would start with. It shows the path your Drone took until signal was lost and the strength of the GPS signal. It even shows the number of satellites being picked up. For example:
View attachment 39923

Red is bad, orange is good. You need to look at your flight data and see the GPS data.

My guess is you encountered a loss of controller signal at the same time there was a GPS loss. The Drone would not be able to RTH at this point. It would eventually land right below this last

It is a good tip - thanks ! I just registered at healthydrones.
Let me see if I can find the right data and I will upload it
 

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