mike.wildlight
lvl.4
Flight distance : 5623 ft
Australia
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That is precisely the point, without a bit of research it's easy to jump to the conclusion that "it knocked out something as big as a power grid. WOW if it can do that what can it do to my little quad!" Where in reality with a bit of research you come to the understanding that power grids are more susceptible to this phenomena than these little flying machines.
I started looking into the space phenomena as a genuine concern, but knowing many commercial pilots, people who earn their living with telemetry, and having commissioned and been involved with large UAV surveys, I was curious as to why I'd never heard it mentioned before. In fact I'm not aware of any DJI literature that mentions it as a risk (Have never gone looking for that in DJIs literature either).
This is some of the factual information I've come across:
http://www.swpc.noaa.gov/impacts/space-weather-and-gps-systems
It mentions GPS accuracy errors of 10s of meters during a severe space weather storm rather than catastrophic signal failures.
"The principal users affected by geomagnetic storms are the electrical power grid, spacecraft operations, users of radio signals that reflect off of or pass through the ionosphere, and observers of the aurora."
This is the official NOAA GPS dashboard which refers to a lot more than just Kp:
http://www.swpc.noaa.gov/communi ... community-dashboard
For an explanation of Kp, relationship to geomagnetic storms and their the effects have a look at the geomagnetic storm tab here:
http://www.swpc.noaa.gov/noaa-scales-explanation
Even at severe they refer to degradation of the system rather than "failure".
From this data use Kp 8 or more as your conservative threshold rather than the 5 that is commonly discussed.
At 9 or over the GPS satellites can shut down so yep that's gonna stuff it for GPS flight for sure.
http://www.sdr.gov/docs/185820_Space_FINAL.pdf
This document refers to the disaster risks associated with solar events. It describes in a very severe event back in 2006 which caused the loss of the WAAS system (which I'm pretty sure is not used by DJI anyway) for 10hours on two consecutive days and widespread GPS outages. In these conditions you would not get a GPS fix to start with in the affected areas or a significantly reduced number of satellites.
http://www.swpc.noaa.gov/impacts/space-weather-and-gps-systems
This page was the source of my earlier quote and states (more fully) "In calm conditions, single frequency GPS systems can provide position information with an accuracy of a meter or less. During a severe space weather storm, these errors can increase to tens of meters or more." Again though, 10s of meters is not going to cause catastrophic fly-ways, or be an explanation for signal losses.
http://hesperia.gsfc.nasa.gov/sftheory/spaceweather.htm
This also just refers to the degradation of GPS signals as discussed above.
So this may affect GPS signal but not the LOS telemetry or control systems. I use GPS a lot in both my personal and professional lives and never had anything other than temporary and minor glitches which can usually be attributed to terrain, vegetation or heavy cloud. I’m thinking that using Kp as a reason not to fly or an explanation for fly-aways in most circumstances is a bit of a stretch
I'm lucky enough to know some very smart people experienced in the professional use of telemetry and GPS, none of whom believe there is a significant risk with all but the most extreme events.
As far as I can see the science doesn't support the fear factor.
Looking at the science I can only come up with two scenarios.
1) The community has a disproportionate wariness of solar storms to the actual risk.
2) The DJI tech is unusually susceptible to issues related to solar storms.
Of these I believe the former is far more likely scenario.
I haven't noticed any formal literature from DJI suggesting the people check Kp and do not fly above a certain value.
I have a passion for science and the truth and I too frequently see the well intentioned, repeating what amounts to speculation as truth and fact. I seem to have a annoying (to me and probably to others) compulsion to correct that.
So I would say, do not spread fear, spread knowledge and make informed decisions.
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