Space weather and GPS accuracy

Does anyone have knowledge about how space weather affects GPS accuracy? What is the L1 position error displayed in this chart? Global Positioning System (GPS) Community Dashboard | NOAA / NWS Space Weather Prediction Center because it’s large for mid-atlantic USA at some times. Do strong geomagnetic storms affect GPS performance (G4 (Severe) Geomagnetic Storm Alert on 24 March UTC-Day | NOAA / NWS Space Weather Prediction Center)?

@Yuri_Rage have you looked at this at all?

Thanks in advance-

I’ve paid little to no attention, and I’ll tell you why…though it’s a bit anecdotal.

In a previous life, we used to have the “space weather” guy show up to flight briefings, and he’d give this longwinded presentation about how much impact solar flares and such would have on GPS performance for the day. Even on the days where he showed a bunch of red all over the slides and preached doom and gloom about space weather impacts, we saw no tangible evidence of it. Eventually we stopped inviting him to talk!

I’m not saying there are no impacts at all, but it’s my estimation that this isn’t much of a consideration for our use cases, and we are better off spending time tuning the physical attributes rather than worrying about the ethereal.


There is the occasional post here warning of K-index catastrophe coming and I have not seen anything tangible materialize from it.

1 Like

Some of the survey folks I work with will talk about issues for their data. But they are working at sub 1cm accuracy so I can’t really argue with them about it.

For @Christopher_Milner and I, running Rovers over predefined patterns, repeatability is the key. When I settle into a routine with a stable tune and firmware version instead of chasing the latest and greatest gadgets and features, my mower wears ruts into the yard, rarely skips a spot (more accurately, always skips the same few spots), and always gives the same margin to obstacles I’ve planned around. It’s easily repeatable to well within 6 inches over the course of weeks if not months.

That repeatability is achieved via a moving baseline configuration of Zed-F9P modules from ArduSimple on the mower and another F9P as the fixed base, along with never accepting less than an RTK Fixed solution.

It might be interesting to verify that claim by setting up a nav mission and using a LIDAR at a fixed location/post to measure the mower’s repeatability on a known path, making measurements in varying space weather conditions. Of course, that would require me to stop changing the tune, chasing the elusive 4.3+ position controller settings.

Thanks @Yuri_Rage and I agree… 20" lawn mower tires (my rover weighs 420 lbs) leave marks in the yard when the rover drives exactly the same lines (within an inch or two) each time. Because of this I had to change my approach to have two missions for each yard I mow and to alternate between the two of them. If I ever see GPS degradation due to space weather I’ll report back to the group - but so far so good.


When the new nav controller was first introduced, I made a test mission “racetrack” of sorts and ran it repeatedly over the course of a few weeks of testing and tuning. You can see that pattern in more recent satellite imagery of my yard :rofl:

1 Like