My Mavic has suddenly gotten “weak GPS signal” while flying this week. Is this normal? Flight log pics included.

[Ejp1288]

That's not most "normal" surfaces.
That's just steel and reinforced concrete (because it's half steel) surfaces.
They don't cause you to lose GPS.
They can cause a yaw error which can end up badly.

But you haven't been moderating drone forums for the last few years.
I see similar cases every week

If they did, there would be a lot more crashes.

You could try passing a magnetic compass over the launch spot and observing it.
It's not an issue with your drone. It will be an issue with where you launched it.
No need to exchange it.

And how can you tell that?

Chances are that it was something within inches of your compass (like in the concrete).
It would have to be a much larger magnetic source if it was several feet away.

I guess I am just really frustrated this is happening to me. I will go out and get a Magnetic Compass. You suggest that in order to see if my sidewalk is the issue, then my compass on top of the concrete will start acting kinda crazy?

EDIT: Just went out there with my magnetic compass and put it on the ground where it happened and there was nothing special about it. The readings were very consistent, nothing weird happened at all.

 

[Ejp1288]

Here are the logs to my other Flight with the issues. Had compass error towards the beginning then was fine for 12 minutes and then got Yaw errors out of no where.

DJI Flight Log Viewer - PhantomHelp.com

 

[Live LA]

Hi all! Glad to find this place.

I got my Mavic last week and have flown it 4 days now. 2 of those days while I’m in the air, I’ve gotten “weak gps signal” completely out of no where and it goes until ALTI mode causing me to nearly crash. This has happened at the park and in a neighborhood.

Like I said, I have full bars and 17 satellites usually and then boom the bars go away and the weak gps signal happens.

Is this common? Or is something wrong with the drone? I have done a lot of calibrations btw.

Attached are flight log info with tons of error messages. I got Yaw error for a while along with other errors. Any ideas?

Thanks!

I dont know about common but yes I have had it return to home on me 2 times is really close proximity of about 500-800 ft at 150-200 alt. Havent heard much help on here other than “re calibrating” but Im with you, and I see there are others with the same problem

 

[Ejp1288]

I dont know about common but yes I have had it return to home on me 2 times is really close proximity of about 500-800 ft at 150-200 alt. Havent heard much help on here other than “re calibrating” but Im with you, and I see there are others with the same problem

Right, its very serious too just because it can drift away and damage property or something. This has happened far too much on just my practice runs so I am terrified to take it out to a client's place of business. I am hoping between this forum and DJI support, we will get this sorted out. I kinda hope its a bad drone and i get it replaced.

 

[Marko9219]

Maybe because they didn't want it to crack or break up easily?
In my part of the world, any concrete driveway is always going to be reinforced.

Fact is, it would be extremely rare to find a reinforced sidewalk.

 

[Marko9219]

To OP

META4 is right. Do not launch from concrete sidewalk. Why take risk? You won’t believe that on grass lawn with sprinkles system sometimes will cause calibration errors. Any DIY launch pad works good. I use a 3x4 plywood

I've personally never in my life seen a sprinkler system containing ferrous piping. I'm sure there's a few oddball antique systems where someone used galvanized piping, but I'm 64 and I've never once encountered it under a lawn. PVC and Poly is all that's been used in the last 40 years I've been involved in sprinkling systems. Even the old valves are brass. New ones are PVC. A few old homes still have iron pipes between the street and the home, but that's becoming scarce. In anything built in the last 40 years I've worked with, there is just no iron typically used anywhere underground.

 

[Montana John]

I am not alone! I get the same message when I use my Android phone or my Ipad. And both of them work fine tracking my position on google maps. The problem this "weak signal" causes is that I cannot use Return to Controller for my RTH option. Solutions, besides storming MJI?

 

[JDawg]

Here are the logs to my other Flight with the issues. Had compass error towards the beginning then was fine for 12 minutes and then got Yaw errors out of no where.

DJI Flight Log Viewer - PhantomHelp.com

This will be an interesting one I think.

 

[JDawg]

I dont know about common but yes I have had it return to home on me 2 times is really close proximity of about 500-800 ft at 150-200 alt. Havent heard much help on here other than “re calibrating” but Im with you, and I see there are others with the same problem

Ever posted your flight log and asked for help? With this being your second post on the forum my guess is no.

 

[JimCanada]

I've never seen a neighborhood sidewalk reinforced! Why would you reinforce a sidewalk? Even my driveway, where trucks and cars are parked, is not reinforced. I launch from my driveway and sidewalk constantly.

They use steel rebar in 90% of concrete

 

[JDawg]

They use steel rebar in 90% of concrete

That and steel mesh. Some local codes probably allow for there to be no reinforcement but that majority do. There are dozens of threads where the problem of a fly away or erratic behavior is reinforced concrete but some have to learn the hard way.

 

[Mossiback]

...I got my Mavic last week and have flown it 4 days now. 2 of those days while I’m in the air, I’ve gotten “weak gps signal” completely out of no where and it goes until ALTI mode causing me to nearly crash. This has happened at the park and in a neighborhood.

Like I said, I have full bars and 17 satellites usually and then boom the bars go away and the weak gps signal happens...

Is your Mavic maintaining a clear view of the sky when this happens? A sudden weakness of GPS signals could be from dropping into a confined space like in a canyon, next to a wall, in trees, etc. I do not think any magnetic interference like what has been discussed will cause a loss of GPS reception.

 

[Ejp1288]

Is your Mavic maintaining a clear view of the sky when this happens? A sudden weakness of GPS signals could be from dropping into a confined space like in a canyon, next to a wall, in trees, etc. I do not think any magnetic interference like what has been discussed will cause a loss of GPS reception.

No it was wide open space. One time it was next to some trees but wasn’t very thick trees or anything out of ordinary.

It’s a mix of GPS being lost, compass errors and yaw errors. It’s a mess.

 

[DanMan32]

They use steel rebar in 90% of concrete

Not with my experience.
If it's structural as for a building, then yes, it's likely. But not usually for sidewalks or driveways.
Heck, even homes built on slabs don't have rebar. No interference warnings on the floor of my home or my dad's for my M2 or my P3. I have gotten them in buildings I work in though.

 

[Ejp1288]

That and steel mesh. Some local codes probably allow for there to be no reinforcement but that majority do. There are dozens of threads where the problem of a fly away or erratic behavior is reinforced concrete but some have to learn the hard way.

How can you tell if concrete is going to cause a magnetic problem? I put my magnetic compass against the same sidewalk I used and it didn’t act weird or anything .

 

[JDawg]

How can you tell if concrete is going to cause a magnetic problem? I put my magnetic compass against the same sidewalk I used and it didn’t act weird or anything .

Not saying it is the case with you. If the direction arrow on your screen is not pointing in the same direction as your drone is pointed then you have a problem.
It will be interesting to see what Meta4 or sar104 has to say about your flight log, something weird is going on I think.

 

[Chip]

How can you tell if concrete is going to cause a magnetic problem? I put my magnetic compass against the same sidewalk I used and it didn’t act weird or anything .

Related question: can we not rely on mavic to tell us if it’s bad location with mag interference? Mine has done so on several occasions and I have assumed it’s reliable.

 

[Ejp1288]

Related question: can we not rely on mavic to tell us if it’s bad location with mag interference? Mine has done so on several occasions and I have assumed it’s reliable.

Well I get the GPS error while in the air and then it’s too late. If it told me not to launch because of Mag interference then that would be great.

 

[DanMan32]

Not saying it is the case with you. If the direction arrow on your screen is not pointing in the same direction as your drone is pointed then you have a problem.
It will be interesting to see what Meta4 or sar104 has to say about your flight log, something weird is going on I think.

Careful about that test. It requires that the device's compass running the app is accurate, and I've yet to come across a phone or tablet who's compass is accurate without having calibrated it at point of use.

 

[Ejp1288]

Some other updates:

1) I have never been in an actual Warning Zone according to the DJI app but every time I have launched a flight it tells me I am entering in an Airport Zone which is never correct.

2) It seems to always slowly pan to the right when hovering in the air no matter the altitude. It can be up 5 feet with no wind and it still slowly pans to the right. Very frustrating. I dont even necessarily get an error message when that happens.