What is the KP Index, and why does it matter?
It’s important that all drone pilots understand the KP index.
It’s almost more important than the wind index as it affects the drones ability to know where it is and to take photos at the right time, at the right place. Most drone pilots experience dreaded “fly-aways” when the KP level is not being acknowledged and they decide to commence their flight mission anyway. But what is the KP index exactly? Let’s get into it…
In summary, the KP Index is a measurement of global geomagnetic activity expressed on a scale of 1-9. In general, anything lower than level 4 means the geomagnetic activity is “Quiet”. At level 4 the geomagnetic activity is called “disturbed” and anything more than level 4 means we are experiencing a magnetic storm.
This type of interference is in short caused by things like solar activity and has a huge impact on our abilities as drone pilots to safely operate our drones via GPS.
Solar Storm and Space Weather - NASA’s Frequently Asked Questions
Solar activity interferes with GPS signals basically due to disruptions in the ionosphere.
A sudden ionospheric disturbance (SID) is any one of several ionospheric perturbations (AKA deviations and fluctuations caused by an outside influence) resulting from abnormally high ionisation or plasma density in the D-region of the ionosphere, and caused by a solar flare and/or a solar particle event (SPE).
There are two main interference instances:
A decreases in the signal-to-noise ratio, affecting carrier frequency, causing the receiver to lose lock on some satellites. Instead of 9 satellites, one might lock onto only around 6, or the number might fluctuate from second to second.
A change in the propagation delay through the ionosphere, making GPS positioning grossly inaccurate even if the receiver has all satellites locked. In essence, causing loss of accurate positioning capabilities.
PS positioning is particularly important for technical drone surveys such as those AGMO conducts as each image (called a “tile”) taken with the any of the advanced camera sensors onboard, need to be accurately geo-tagged for streamlined image stitching in order to create accurate and precise orthomosaic maps prior to processing for detailed analytics.
It is often said that photogrammetry is more art than science. But we believe it is probably a healthy dose of both. Since there are multiple factors that help to determine the quality of a drone map, a lot need to go right, or it will all go wrong! Now factor in the actual flying of the drone itself to get the job done, with an epic magnetic storm on the boil. Think: preparing for a rocket launch. So many factors, so much to check, and so beautiful when it all goes right. Until it doesn’t.
The best thing we can do to prevent a KP Index related accident is to more prevention than cure - simply binge aware of the KP Index helps.
If your GPS signal degrades or fails entirely, you will be forced to complete the flight survey in ATTI mode - a flight mode where the GPS positioning and other visual positioning systems are disabled - basically flying “on manual”. Any pilot worth their salt needs to ensure they are comfortable navigating and landing their UAV’s in this mode, even if in high winds or operating in complicated terrain.
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