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What are "polar areas"?

Grimbart55

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According to the Mavic Manual, flights in P-mode in "polar areas" are not possible (page 50). I was flying in northern Finland and experienced quite frequent drops from GPS to Atti mode in mid flight, and GPS was not recovered for 1-2 minutes - quite scary. Analysing the log files, I noticed GPS health problems, while there were still many satellites registered. Is this a consequence of this restriction? Anybody else had similar experiences? Can "polar areas" be defined more clearly, i.e. by latitude?
 
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msinger

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Red_Raven

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I'm located in Iceland, 66N. I fly both mavic and phantom without any complications.
 

Robbyg

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I think it has more to do with the low budget GPS system in the Mavic. This is probably a case where you definitely want to be running .0500 firmware and up as it makes the GPS lock with a lower signal quality level. From what I am reading older GPS units have problems in the polar regions but new ones work fine. I suspect the $25 GPS board in the Mavic is no better than an expensive older GPS module.

Rob
 

AlanTheBeast

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According to the Mavic Manual, flights in P-mode in "polar areas" are not possible (page 50). I was flying in northern Finland and experienced quite frequent drops from GPS to Atti mode in mid flight, and GPS was not recovered for 1-2 minutes - quite scary. Analysing the log files, I noticed GPS health problems, while there were still many satellites registered. Is this a consequence of this restriction? Anybody else had similar experiences? Can "polar areas" be defined more clearly, i.e. by latitude?

The physical problems with high latitudes are:

Mag compass.
For most of the world the magnetic lines are close to parallel with the surface of the earth, but bend in towards the poles. This makes the Mavic's on board mag compasses unable to determine mag north accurately when close to the magnetic north poles. Since DJI seem bent to make the mag compass the sole heading reference, it should refuse to fly. This is the "not possible" part.

Since mag north is not coincident with true north, latitude alone does not determine where it drops off. I usually associate "polar region as above 75°N/S - but one could decide that it is 66.5°N (roughly the arctic circle) if one prefers. I have no idea where DJI set it - and it might simply be decided by the mag compass s/w on the drone - where the vertical vector is too high, they refuse to fly.

Right now (ish) the mag north pole is opposite the north pole from Finland so it should have least effect where you are.

GPS. The DJI drones use a very sensitive receiver (at least for the GPS side - not sure about the GLONASS side). Too sensitive is a bad thing in GPS and can result in huge errors. In the polar regions this might mean a high sensitivity to charged particles diving down into the upper atmosphere (follows those magnetic lines). The over sensitive GPS of the Mavic might not be able to track sats well in these conditions. We're on the waning side of the solar cycle - so this might not be "it".

There are a lot of reports of GPS dropping out at all latitudes - whether you being in northern Finland makes that worse or not is hard to tell.
 
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AlanTheBeast

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I think it has more to do with the low budget GPS system in the Mavic. This is probably a case where you definitely want to be running .0500 firmware and up as it makes the GPS lock with a lower signal quality level. From what I am reading older GPS units have problems in the polar regions but new ones work fine. I suspect the $25 GPS board in the Mavic is no better than an expensive older GPS module.

Rob
I'd rather the GPS never lock on low signal quality. Aviation receivers, BTW, are very conservative in this regard - less is really more.
 

Phill B12

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According to the Mavic Manual, flights in P-mode in "polar areas" are not possible (page 50). I was flying in northern Finland and experienced quite frequent drops from GPS to Atti mode in mid flight, and GPS was not recovered for 1-2 minutes - quite scary. Analysing the log files, I noticed GPS health problems, while there were still many satellites registered. Is this a consequence of this restriction? Anybody else had similar experiences? Can "polar areas" be defined more clearly, i.e. by latitude?
When you were in northern Finland how far north of the Arctic Circle were you? I'll be taking my Mavic to northern Canada in March (working there) and I'll be about 200 miles north of the Arctic Circle.
 

Phill B12

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There are many different definitions of "polar regions". North of 60N? North of 65N? or north of 70N? And why is this restriction? There are lot's of GPS and GLONASS satellites in sight at high latitudes.
I'll be working at 69.32 N. Its a very cold and windy community so the weather could be a bigger factor than GPS issues. I'll find out.
 

Grimbart55

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Was flying at 69.5N. And last September also at the same latitude but in North-eastern Siberia on the Arctic sea coast. But I think it's the geomagnetic latitude that matters. For that you are in Canada worse off. I also noted a clear correlation with solar activity: The errors were much more frequent when the solar activity was high. I think the compasses get confused which somehow also impact how the GPS signal is interpreted by the AC navigation system. Had never such issues in lower latitudes.
 

ascension

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I suspect it is compass related as well.
Without going into great and boring detail, when you get really far north, true vs magnetic north becomes a real issue. Obviously, simple compass systems don't have the ability to figure that out.
When airliners fly northern routes they swap from magnetic to true calculations, and when really north, on what are called polar routes, they swap into what is called "grid" mode.
I doubt a drones really simple compass system can figure this out.
 

Rocky43

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Hi guys,

Im going to Svalbard, will the Mavic Pro fly though ?
 

Grimbart55

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Sure, it will fly. Just be careful in case it looses compass and/or GPS and you will have to manually fly it back.
 

Phill B12

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According to the Mavic Manual, flights in P-mode in "polar areas" are not possible (page 50). I was flying in northern Finland and experienced quite frequent drops from GPS to Atti mode in mid flight, and GPS was not recovered for 1-2 minutes - quite scary. Analysing the log files, I noticed GPS health problems, while there were still many satellites registered. Is this a consequence of this restriction? Anybody else had similar experiences? Can "polar areas" be defined more clearly, i.e. by latitude?
I've flown my Mavic Pro in Resolute Bay, Nunavut, (74'45" degrees north) and in Chesterfield Inlet, Nunavut(63' North). Both times were in winter conditions, colder than minus 30 Celsius. GPS Satellites weren't the problem, the cold was the greatest factor, both for the drone and the operator. Frozen fingertips don't work well on a touch screen, and the cold affected motor performance with a slight shimmy at takeoff until they warmed up. Flight duration was reduced due to battery temperatures. I picked up more GPS satellites up north than in southern Canada. I never had a problem with the GPS mode, however because every arctic community has an airport close to town or right in town the warning messages about the proximity of the runway caused the video feed to lock up so it appeared the drone wasn't moving when it was. With only two flights a day avoiding any potential conflict with aircraft is not a problem. A phone call to the Air Radio Station at the airport confirmed no flights within several hours of my planned flight times. Flying at low altitudes less than 100' AGL) avoided any stronger winds higher up and any possible conflict with aircraft. I've fixed the frozen fingertip problem with electric heated glove liners and a screen stylus.
 

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