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Magnetic Interference - no GPS no ATTI no OPTI- work arounds

SkyScan

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I'm trying to get a shot in a magnetic hotspot - an abandoned building made up of steel and concrete with two large 13 story voids as its central features. These voids rise from the mezzanine up towards an open skylight.

35366245_10160600763215385_3297199114139205632_n.png

The idea for my shoot is to fly up the 13 floors looking down and then either out the skylight rising to 500 ft or to separate the flight into two (internal from the ground floor and external from the roof) with a clever edit to stitch them together.

But the magnetic interference means the GPS signal gets mangled and there is not enough light to fly in Opti (at least it reverts to Atti after being in Opti briefly) and in Atti it restricts the altitude to 30 ft (probably a good thing).

I tried to solve this issue by getting a GPS signal from the roof and flying the mavic into the building whilst hanging over the skylight with a rope. My rational here was that if it lost signal it would emergency land and that if the remote had a lock on GPS and I was pointing the antenna at the drone it would behave. Stupid I know....

The results are worth watching here as my drone drops in and takes a tumble on the 9th floor.

Benjamin Bush on Instagram: “Magnetic interference! This is what happens if you drop into a magnetic hot spot. Your RC goes from GPS mode to Atti to Opti before getting…”

So...

Does anyone have any ideas? I don't / can't risk my mavic but I want the shot. I also want to map the internal guts of the building so I need to be able to fly in there.

Does the craft need a GPS lock along with the RC in order to behave? And why can't I fly in Atti mode above 30 ft? Is it because it literally will go bat **** insane? If not can I hack the drone to allow it?

Do people use GPS relays to get GPS signals in hard to get to locals? (Too expensive an option for me here I think)

I'm interested to know from professional drone operators as I'm sure this is a common issue in construction UAV work and as I want to move into LIDAR applications I'd like to hear more. Does RTK solve issues like this?

Thanks in advance.

Sorry for the long post - I recommend watching the vid its pretty narly by my mavic standards! lol
 

Dronason

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Welcome

GPS relays would be useless and dangerous. The Mavic will think probably think it is at location of the antenna of the GPS relay, so very dangerous way.

Magnetic interference and GPS are not directly related. Metallic structure will influence the compass of the MP.
The structure can also obstruct the view to satellites and reduce the number of visible satellites. If there is only one building, should not be a big issue.

In the case of a building with a full metallic structure, as in the video, there is need for some space on the sides, user prop guards and train to fly in ATTI mode. Remain also a dangerous work.
The modes are GPS - OPTI - ATTI. GPS is the best, OPTI will use camera to stabilize horizontally, ATTI has no horizontal stabilization, pilot has to take care of horizontal position with the sticks.
In ATTI mode it is not easy to pilot it, especially in presence of wind.

If you keep your distance from the steel structure, there should not a be too big issue if there is not too much building around.
Better to use prop guards, train to fly in ATTI mode (you can try in a large underground garage), plan the flight for a day with no wind, insure there is no warning about magnetic interference, leave the MP get full GPS signals before taking off.
In case anything looks strange, better to increase the distance to the building and land.
Maybe you can train yourself on a smaller metallic structure.

Maybe some other pilots with more experience will give you good advise based on their experience.

Good luck.
 
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SkyScan

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Welcome

GPS relays would be useless and dangerous. The Mavic will think probably think it is at location of the antenna of the GPS relay, so very dangerous way.

Magnetic interference and GPS are not directly related. Metallic structure will influence the compass of the MP.
The structure can also obstruct the view to satellites and reduce the number of visible satellites. If there is only one building, should not be a big issue.

In the case of a building with a full metallic structure, as in the video, there is need for some space on the sides, user prop guards and train to fly in ATTI mode. Remain also a dangerous work.
The modes are GPS - OPTI - ATTI. GPS is the best, OPTI will use camera to stabilize horizontally, ATTI has no horizontal stabilization, pilot has to take care of horizontal position with the sticks.
In ATTI mode it is not easy to pilot it, especially in presence of wind.

If you keep your distance from the steel structure, there should not a be too big issue if there is not too much building around.
Better to use prop guards, train to fly in ATTI mode (you can try in a large underground garage), plan the flight for a day with no wind, insure there is no warning about magnetic interference, leave the MP get full GPS signals before taking off.
In case anything looks strange, better to increase the distance to the building and land.
Maybe you can train yourself on a smaller metallic structure.

Maybe some other pilots with more experience will give you good advise based on their experience.

Good luck.
Thank you so much for replying. I've really been at a loss with this one. Some issues however.. As soon as the mavic connects it pretty much engages ATTI mode.

When in ATTI it caps the altitude at 30ft which is a real problem as I need to fly the 13 stories internally. Any way I can overcome the cap on altitude you might know of? I'm confident flying in atti although there are some serious drafts running through the floors which make it risky and I need the shot to be steady.

The voids runs within the building like this: (photo attached)



I tried to overcome this two ways,

1 you can see in the video crash I tried flying from the roof with a GPS signal registered and then dropping through the Skylight. This turned out to be a terrible idea as I seemed to lose connection when 5 or so meters in and the drone either drifted or got caught in a wash as it stopped responding (my guess as it switched to Atti mode from GPS) and then smashing into the wall.

2. I tried flying off the 4th floor (most floors are open and exposed). So on the 4th I connected in atti mode but as soon as I flew off the balcony into the void it dropped to 30ft (which was below me) and then lost the ability to rise in altitude. As I had forced hoover mode on instead of RTH I had to emergency land on the nearest floor (which again was very risky).

Do you think there is a way I could force Opti mode? Maybe white markers on the balconies like in camera tracking for VFX compositing?

I've ordered a parabolic antenna guard but I doubt this will help. received_10160679933260385.jpeg
 

sar104

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Thank you so much for replying. I've really been at a loss with this one. Some issues however.. As soon as the mavic connects it pretty much engages ATTI mode.

When in ATTI it caps the altitude at 30ft which is a real problem as I need to fly the 13 stories internally. Any way I can overcome the cap on altitude you might know of? I'm confident flying in atti although there are some serious drafts running through the floors which make it risky and I need the shot to be steady.

The voids runs within the building like this: (photo attached)



I tried to overcome this two ways,

1 you can see in the video crash I tried flying from the roof with a GPS signal registered and then dropping through the Skylight. This turned out to be a terrible idea as I seemed to lose connection when 5 or so meters in and the drone either drifted or got caught in a wash as it stopped responding (my guess as it switched to Atti mode from GPS) and then smashing into the wall.

2. I tried flying off the 4th floor (most floors are open and exposed). So on the 4th I connected in atti mode but as soon as I flew off the balcony into the void it dropped to 30ft (which was below me) and then lost the ability to rise in altitude. As I had forced hoover mode on instead of RTH I had to emergency land on the nearest floor (which again was very risky).

Do you think there is a way I could force Opti mode? Maybe white markers on the balconies like in camera tracking for VFX compositing?

I've ordered a parabolic antenna guard but I doubt this will help. View attachment 41430
The advice @Dronason gave you is good. The only way to fly this is in ATTI mode which, realistically, would require you to modify the firmware to change the mode switch sport setting to ATTI. That's relatively easy. Then you still have to be able to fly the aircraft in a fairly tight space with no position hold which is going to require direct visual contact. At least there are unlikely to be lateral air currents in that space.
 
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Dronason

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...
Do you think there is a way I could force Opti mode? Maybe white markers on the balconies like in camera tracking for VFX compositing?
...
OPTI mode is fully automatic and it requires unfortunately a minimum level of light, I am afraid there is probably not enough light in your case.
 
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SkyScan

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Thank you both! OK I'll try and force atti by modifying firmware (I've seen a tutorial somewhere). But please do you know if that will solve the issue of the altitude ceiling at 30ft? Thank you
 

SkyScan

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Can a admin move this thread to the Mavic Pro section? I am new to the app so posted in the wrong place. Thanks
 

Lake_Flyer

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Thank you both! OK I'll try and force atti by modifying firmware (I've seen a tutorial somewhere). But please do you know if that will solve the issue of the altitude ceiling at 30ft? Thank you
If you force it into thrue Atti mode with the firmware mod there will be no alt limit of 30ft. That limit is only for Opti mode. The VPS sensors have a reach of 30ft.

As a professional I would not take the job, not with a Mavic anyway.
 
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SkyScan

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If you force it into thrue Atti mode with the firmware mod there will be no alt limit of 30ft. That limit is only for Opti mode. The VPS sensors have a reach of 30ft.

As a professional I would not take the job, not with a Mavic anyway.
Thanks that's good news. I should point out this is not a paid job. Its a cinematic / artistic experiment of my own volition. As I have access to the site and have an idea in mind which I believe will be effective I'm prepared to take a calculated risk. I'm confident even in Atti mode I won't crash again as I'll take a step by step approach from the ground up (no more Skylight downs!)

The shot has to be split into two anyhow due to the change in light from inside to outside and the need to change ISO and add an ND filter. I'll need to shoot the external "rise" separately with ND filters which means no reason to fly through the Skylight. This makes the flight a lot less risky.

What would you use as a professional and why? I asked in the original part about rtk and if that would allow accurate control in a magnetic environment.
 

Lake_Flyer

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What would you use as a professional and why?
Well, as a pro I wouldn't be allowed to temper with the firmware since it would not correlate with my operational manual. But I use an Inspire1 for anything that requires Atti mode.

I would have to see it for myself, difficult to judge from a picture. I might just not fly at all inside. For the vault I might think about lowering the I1 with two lines attached to the motor arms at the COG spot and use a winch of some sort. The camera stabilisation would still do its work. Or do the same but with an OSMO. For the outside shots I would just fly my Inspire1 in GPS or Atti, whatever is required to get the shots. I would prefer a day without wind at altitude of course.
 

SkyScan

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Well, as a pro I wouldn't be allowed to temper with the firmware since it would not correlate with my operational manual. But I use an Inspire1 for anything that requires Atti mode.

I would have to see it for myself, difficult to judge from a picture. I might just not fly at all inside. For the vault I might think about lowering the I1 with two lines attached to the motor arms at the COG spot and use a winch of some sort. The camera stabilisation would still do its work. Or do the same but with an OSMO. For the outside shots I would just fly my Inspire1 in GPS or Atti, whatever is required to get the shots. I would prefer a day without wind at altitude of course.
Excellent! Thanks. I was considering lowering on a pulley or similar but a bit of a ball ache to justify setting up thanks again. Next attempt on Sunday...
 

Dragonfly

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Excellent! Thanks. I was considering lowering on a pulley or similar but a bit of a ball ache to justify setting up thanks again. Next attempt on Sunday...
Personally I would use a stiff fishing rod with a game type reel and just lower the Mavic manualy down the tower from the top and wind it back up again while filming.
 
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HoozierDroneDaddy

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I'm trying to get a shot in a magnetic hotspot - an abandoned building made up of steel and concrete with two large 13 story voids as its central features. These voids rise from the mezzanine up towards an open skylight.

View attachment 41394

The idea for my shoot is to fly up the 13 floors looking down and then either out the skylight rising to 500 ft or to separate the flight into two (internal from the ground floor and external from the roof) with a clever edit to stitch them together.

But the magnetic interference means the GPS signal gets mangled and there is not enough light to fly in Opti (at least it reverts to Atti after being in Opti briefly) and in Atti it restricts the altitude to 30 ft (probably a good thing).

I tried to solve this issue by getting a GPS signal from the roof and flying the mavic into the building whilst hanging over the skylight with a rope. My rational here was that if it lost signal it would emergency land and that if the remote had a lock on GPS and I was pointing the antenna at the drone it would behave. Stupid I know....

The results are worth watching here as my drone drops in and takes a tumble on the 9th floor.

Benjamin Bush on Instagram: “Magnetic interference! This is what happens if you drop into a magnetic hot spot. Your RC goes from GPS mode to Atti to Opti before getting…”

So...

Does anyone have any ideas? I don't / can't risk my mavic but I want the shot. I also want to map the internal guts of the building so I need to be able to fly in there.

Does the craft need a GPS lock along with the RC in order to behave? And why can't I fly in Atti mode above 30 ft? Is it because it literally will go bat **** insane? If not can I hack the drone to allow it?

Do people use GPS relays to get GPS signals in hard to get to locals? (Too expensive an option for me here I think)

I'm interested to know from professional drone operators as I'm sure this is a common issue in construction UAV work and as I want to move into LIDAR applications I'd like to hear more. Does RTK solve issues like this?

Thanks in advance.

Sorry for the long post - I recommend watching the vid its pretty narly by my mavic standards! lol

Watch this video. I will show you how to modify the Mavic Pro (only) so that you can get true ATTI mode, not OPTI. Hope this helps.

 
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Antipodean

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Welcome

GPS relays would be useless and dangerous. The Mavic will think probably think it is at location of the antenna of the GPS relay, so very dangerous way.

Magnetic interference and GPS are not directly related. Metallic structure will influence the compass of the MP.
The structure can also obstruct the view to satellites and reduce the number of visible satellites. If there is only one building, should not be a big issue.

In the case of a building with a full metallic structure, as in the video, there is need for some space on the sides, user prop guards and train to fly in ATTI mode. Remain also a dangerous work.
The modes are GPS - OPTI - ATTI. GPS is the best, OPTI will use camera to stabilize horizontally, ATTI has no horizontal stabilization, pilot has to take care of horizontal position with the sticks.
In ATTI mode it is not easy to pilot it, especially in presence of wind.

If you keep your distance from the steel structure, there should not a be too big issue if there is not too much building around.
Better to use prop guards, train to fly in ATTI mode (you can try in a large underground garage), plan the flight for a day with no wind, insure there is no warning about magnetic interference, leave the MP get full GPS signals before taking off.
In case anything looks strange, better to increase the distance to the building and land.
Maybe you can train yourself on a smaller metallic structure.

Maybe some other pilots with more experience will give you good advise based on their experience.

Good luck.

Dronason, thanks for the info, it helps for beginners as myself. My question if I can gather more info on the magnetic interferences and how affects to drones, in this case, to be used for professional inspections of merchant ships cargo holds. Inside of those holds with all metallic environmentDSCN0976.JPG
 

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