Found the cause for my MP GPS failure...

[Drgnfli]

I just picked up my MP today from "DJI Arizona Powered by Innovative UAS" store located in Scottsdale, AZ. I had it repaired there because the GPS was turning off immediately after takeoff.

This is what was happening. Just prior to takeoff, I would have an RC green take off light & 12 to 16 GPS satellites & a flashing green tail light. Upon takeoff to the 4' altitude the GPS satellites went blank, RC green light turns to caution, & green tail light on Mavic turns to flashing red. I have hovered at 4' for approx 5 minutes with no changes.

I have calibrated the IMU & compass multiple times; I have updated & reinstalled firmware in the RC & Mavic & updated to the latest software on my tablet & phone. I have switched back & forth between the Pixel Xl phone & the Samsung Tab A many times but get the same errors on the drone & my RC. And no, I have not crashed this drone in months & I have taken off from this spot many dozens of times.

The technician at the DJI AZ store, where I got it repaired, told me that I may have flown to close to high voltage power lines after I told him when it first occurred. I remembered that I had been doing a "Follow Me" flight down a dirt road that was near power lines when my MP first started acting erratically. After I brought it home & attempted to fly from my back deck is when I noticed the lost GPS signal & the warning lights. The DJI AZ technician told me to stay at least 200' away from those power lines at all times. He said if you must fly over them, fly 200' above them & do not fly under them because you cannot stay 200' away. He stated that the power lines emitted EMI which 'toasted' the GPS module in the Mavic Pro.

I hope this helps a few of my fellow flyers on this forum...

 

[laurens23]

The DJI AZ technician told me to stay at least 200' away from those power lines at all times. He said if you must fly over them, fly 200' above them & do not fly under them because you cannot stay 200' away. He stated that the power lines emitted EMI which 'toasted' the GPS module in the Mavic Pro. .

This is not true. Cars (and phones) with GPS drive below power lines all the time.
I also flew my drone next to power lines without issues many times.
one time I accidentally flew between the wires. nothing happened.

Nearby power lines can reduce the signal quality (range) to the controller, but not block, disable or toast GPS.

 

[Kilrah]

It is very unlikely this is the reason, but hey gotta say something that makes the customer happy.

 

[kidroc]

I just picked up my MP today from "DJI Arizona Powered by Innovative UAS" store located in Scottsdale, AZ. I had it repaired there because the GPS was turning off immediately after takeoff.

This is what was happening. Just prior to takeoff, I would have an RC green take off light & 12 to 16 GPS satellites & a flashing green tail light. Upon takeoff to the 4' altitude the GPS satellites went blank, RC green light turns to caution, & green tail light on Mavic turns to flashing red. I have hovered at 4' for approx 5 minutes with no changes.

I have calibrated the IMU & compass multiple times; I have updated & reinstalled firmware in the RC & Mavic & updated to the latest software on my tablet & phone. I have switched back & forth between the Pixel Xl phone & the Samsung Tab A many times but get the same errors on the drone & my RC. And no, I have not crashed this drone in months & I have taken off from this spot many dozens of times.

The technician at the DJI AZ store, where I got it repaired, told me that I may have flown to close to high voltage power lines after I told him when it first occurred. I remembered that I had been doing a "Follow Me" flight down a dirt road that was near power lines when my MP first started acting erratically. After I brought it home & attempted to fly from my back deck is when I noticed the lost GPS signal & the warning lights. The DJI AZ technician told me to stay at least 200' away from those power lines at all times. He said if you must fly over them, fly 200' above them & do not fly under them because you cannot stay 200' away. He stated that the power lines emitted EMI which 'toasted' the GPS module in the Mavic Pro.

I hope this helps a few of my fellow flyers on this forum...

I really hate to hear that trained techs will go out and spread such blatant bull crap lies like this.. That man should be ashamed of himself..

 

[Drgnfli]

All I can say is that is when the crap started happening to my MP. I was within 200' of high voltage power lines when it started to fly away & yaw hard right. I was lucky to be able to bring it down on the road for a quick landing...

 

[ac0j]

A static discharge from something makes more sense. There is no way that there is that much emi around those lines.
I have an acquaintance that used to work on high voltage transfer lines in the mountains. OFTEN he was deployed right on the towers by helicopter. BUT, before he could exit the cabin, he had to suit up and discharge the static that builds up on the chopper to the tower. He told me they sometimes looked and sounded like lightning strikes.
Then again, he also told me they could throw a florescent tube light bulb in the air near the wires and they would glow.

 

[AgPhotoWings]

We have what they call a SWER line (Single Wire Earth Return) running down the middle of our property. I remember flying close to this line, forgetting it was there. The MP started to fly very erratically.....Then I realized it must be interference from the power line.

 

[Drgnfli]

We have what they call a SWER line (Single Wire Earth Return) running down the middle of our property. I remember flying close to this line, forgetting it was there. The MP started to fly very erratically.....Then I realized it must be interference from the power line.

I was thinking after some of these comments on my post that this was not the first time I had a problem with erratic flying but thinking back, it was often when I had passed over or under high powered lines. Plus why would a technician that works in this field "blow smoke" about the cause? It could be that the numerous times I was near the lines somehow accumulated & toasted my GPS module. It is just another point that DJI has not checked out or if they have, not informed the public. Personally, I am going to give those power lines a wide berth from now on...

 

[laurens23]

It could be that the numerous times I was near the lines somehow accumulated & toasted my GPS module.

No. the DJI rep just gave you wrong info. happens all the time and not just at DJI.

 

[caspian]

Drgnfli, speaking as an engineer with some knowledge of the subject, power lines will not disrupt GPS unless you're incredibly close to them. go and stand under power lines and open up the maps function on your phone, does it show your location inexplicably displaced? no.

DJI were shining you on, it's hardly unknown for a customer service rep to make something up to satisfy a customer. anyone working in a retail store is not a "technician" regardless of what DJI calls them to make it sound like you're dealing with someone expert. they're a customer service person who has been trained to operate the product and maybe use a screwdriver to swap broken parts if you are lucky.

 

[dewster]

Mag interference from metal structures?

 

[caspian]

possible i suppose, but gee you would have to be close. I would expect it to affect the compass before the GPS.

 

[sar104]

I was thinking after some of these comments on my post that this was not the first time I had a problem with erratic flying but thinking back, it was often when I had passed over or under high powered lines. Plus why would a technician that works in this field "blow smoke" about the cause? It could be that the numerous times I was near the lines somehow accumulated & toasted my GPS module. It is just another point that DJI has not checked out or if they have, not informed the public. Personally, I am going to give those power lines a wide berth from now on...

There's obviously no harm in staying away from the lines but, as has been mentioned above, they will have no effect at all on GPS reception. They also won't cause any magnetic interference with the compass unless you get really close and, even then, I would be very surprised to see an effect. Transmission lines are high-voltage, low-current, and the magnetic field strength is a linear function of the current, and is voltage independent.

 

[FatherXmas]

I work on the phones for a power company and routinely park my pick-up very close to 500KV switching equipment. None of my electronics ever does anything weird including my gps.

 

[caspian]

I fairly regularly work in a telco lab that's about 1/6th the size of a football field and is crammed to overflowing with high frequency electronics and high current power circuits. no effect on anything from cell phones to test and measurement gear.

including while standing in the RF testing section, which has stern signage not to enter while running if you would like to have children in the future.

 

[sparkorc]

Whilst its prudent not to fly your drone close to high tension power lines, they will not have any effect on the compass as a former linesman the company I worked for had drones for O/H line & transformer inspection, I have also tested this myself flying close with no effect with a dji phantom several years ago, but please don't put your local power supply at risk by causing a incident by testing your drone how close to power lines you can fly stay well away.

 

[Mossiback]

It may depend on how close you are to the power source. Closer to the generating plant I can hear crackling sounds from the power lines yet a few miles down the line there is no noise. It shouldn't affect the MP but perhaps the circuitry is not as robust as it should be.

 

[Drgnfli]

It may depend on how close you are to the power source. Closer to the generating plant I can hear crackling sounds from the power lines yet a few miles down the line there is no noise. It shouldn't affect the MP but perhaps the circuitry is not as robust as it should be.

That is what I am thinking. I have many times come close to the power lines (within 200' but not closer than 50') with no ill effects but maybe it'll affect the GPS module over time - could have been a fault waiting to happen. I have heard people complain that their teeth 'vibrate' or hurt when walking near the lines - who knows what it'll do at any given time...?

 

[Drgnfli]

Drgnfli, speaking as an engineer with some knowledge of the subject, power lines will not disrupt GPS unless you're incredibly close to them. go and stand under power lines and open up the maps function on your phone, does it show your location inexplicably displaced? no.

DJI were shining you on, it's hardly unknown for a customer service rep to make something up to satisfy a customer. anyone working in a retail store is not a "technician" regardless of what DJI calls them to make it sound like you're dealing with someone expert. they're a customer service person who has been trained to operate the product and maybe use a screwdriver to swap broken parts if you are lucky.

He seemed to be a "knowledgeable" guy!

 

[sparkorc]

Whilst this should not be attempted but to prove a point this guy flew close to power lines & transformers, but because the cameras fitted to our drones cannot see power lines easily you run the risk of crashing into them, apart from the risk of damaging your local power supply and getting a huge repair bill for any damage caused.

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