K-index seems to be crucial

[CallMeAlan]

P2V.

Recent experiences lead me to believe that that silly old K-index is really quite important.

First experience: it just refused to calibrate, after telling me it needed it. Just wouldn't. I went home.
Later discovered that K was over 6 that day, possibly even 8.

Second experience: I now had a K-index app on my phone. It read 4 for the day. I needed to calibrate twice before it was happy, and the LEDs remained solid green, no slow flashing. 7 satellites. It flew, but I felt it was not really awfully happy about it, drifting a bit, slowly yawing without being told to.

Third, last Saturday. K-index was 2. 10 satellites. No calibration required, LEDs flashing slow green almost immediately, and it flew like a dream, as though it was on rails.

So, it seems to me we might need to make ourselves quite K-aware. Am I correct in my suppositions?

 

[Mal_PV2_Ireland]

I really haven't noticed any strange behaviour with mine and I always throw an eye to the k index. I've had a few flights while it was showing 6 and I didnt find anything strange.

 

[IrishSights]

I dont think K index affects the compass only the ability to lock satellites.

 

[HarryT]

P2V.

Recent experiences lead me to believe that that silly old K-index is really quite important.

First experience: it just refused to calibrate, after telling me it needed it. Just wouldn't. I went home.
Later discovered that K was over 6 that day, possibly even 8.

Second experience: I now had a K-index app on my phone. It read 4 for the day. I needed to calibrate twice before it was happy, and the LEDs remained solid green, no slow flashing. 7 satellites. It flew, but I felt it was not really awfully happy about it, drifting a bit, slowly yawing without being told to.

Third, last Saturday. K-index was 2. 10 satellites. No calibration required, LEDs flashing slow green almost immediately, and it flew like a dream, as though it was on rails.

So, it seems to me we might need to make ourselves quite K-aware. Am I correct in my suppositions?

No, you're not correct.

K-Index has absolutely nothing whatsoever to do with compass calibration. A high K-index will not affect either the necessity or the ability to calibrate the compass.

The effect of a high K-index is to increase the "uncertainty" of GPS positioning. The worst that can happen with a high K-index is that your Phantom's ability to hover in place might be degraded from wandering about within a 2m-radius circle to a 5m or even in extreme cases a 10m circle. But it won't affect the ability to get a GPS lock in the first place.

 

[N017RW]

Never paid attention, never had a problem.
YMMV

 

[Happyflyer]

.......K-Index has absolutely nothing whatsoever to do with compass calibration. A high K-index will not affect either the necessity or the ability to calibrate the compass.

The effect of a high K-index is to increase the "uncertainty" of GPS positioning. The worst that can happen with a high K-index is that your Phantom's ability to hover in place might be degraded from wandering about within a 2m-radius circle to a 5m or even in extreme cases a 10m circle. But it won't affect the ability to get a GPS lock in the first place.

Is there a record of these values online? I ask because on August 2nd I had a flight that the P2V acted up just as you stated. It wandered all over and was not in atti. Have not had that happen since.

 

[dmagnus]

FWIW: from NOAA

SPACE WEATHER AND GPS SYSTEMS
The use of single and dual frequency radio navigation systems, like GPS, has grown dramatically in the last decade. GPS devices are now in every cell phone and in many automobiles, trucks of all types, and any equipment that moves and needs precision location measurements. High precision GPS using dual frequencies are used for farming, construction, exploration, surveying, snow removal and many other applications.

There are several ways in which space weather impacts GPS. The GPS signal travels from the satellite to the receiver on the ground, and passes through the ionosphere. The ionosphere bends the path of the GPS signal similar to the way a lens bends the path of light. During quiet times, when there is no space weather activity, the GPS system can compensate for the ionosphere, removing much of its impact on the accuracy of the positioning information. When the ionosphere is disturbed due to space weather, however, the signals are delayed which introduces errors in the calculated position.

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. Dual frequency GPS systems can provide position information with accuracies of a few centimeters. In this case the two different GPS signals are used to better characterize the ionosphere and remove its impact on the position calculation. When the ionosphere becomes highly structured, though, the GPS system loses its lock on the satellite signal and then loses the ability to provide position information at all.

Geomagnetic storms create large scale features in the ionosphere. The currents and energy introduced by a geomagnetic storm enhances the ionosphere and increases the total height-integrated number of ionospheric electrons, or Total Electron Count (TEC). The GPS system cannot correct for this enhancement and so errors are introduced into the position calculations. This usually occurs at high latitudes, though major storms can produce large TEC enhancements and gradients at mid-latitudes as well.

Near the magnetic equator there are current systems and electric fields that create instabilities in the ionosphere. The instabilities are most severe just after sunset. These smaller scale (tens of kilometers) instabilities, or bubbles, can have a scintillating affect on the GPS signal, much like waves on the surface of a body of water will disrupt the path of light as it passes through them. Near the equator, dual frequency GPS systems often lose their lock on the GPS signal on a regular basis. These ionospheric scintillations are not associated with any sort of space weather storm, but are simply part of the natural equatorial ionosphere.