The spectacular northern lights were visible to many in the Lower 48 last weekend, thanks to a well-publicized geomagnetic storm that was taking place over a 2-3 day span. But it was also very disruptive to activities in many places in the northern half of the U.S., including to growers who were in their fields working and relying on GPS signals.
According to the Space Weather Prediction Center, part of the National Oceanic and Atmospheric Administration (www.swpc.noaa.gov), “A geomagnetic storm is a major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding the Earth.” And that, according to the SWPC, can, “create strong horizontal variations in the ionospheric density that can modify the path of radio signals and create errors in the positioning information provided by GPS.”
Turns out that’s exactly what happened in some areas. For example, LandMark Implement, a multi-location dealership in Nebraska and Kansas, selling John Deere equipment, posted the following:
Saturday, May 11 - 9:00 a.m. Update:
Yesterday, we sent out a text message advising customers to turn off their RTK and use a grace period of SF2 or SF3. We believe that the SF2 and SF3 accuracy is also extremely compromised as well due to this storm. Due to the way the RTK network works, the base stations were sending out corrections that have been affected by the geomagnetic storm and were causing drastic shifts in the field and even some heading changes that were drastic. Because SF2 and SF3 do not receive all of these corrections, those signals weren’t affected as much, but we do suspect that the pass-to-pass accuracy is extremely degraded while still allowing customers to run. We strongly advise you to keep an eye on your guess rows. We experienced a pass where the guess row was 10 inches wide and the receiver was showing a PDOP value of 1.1 which would typically mean good accuracy. This can also affect your section control, but we don't expect it to create any excessively large overlaps or skips - however, the situation at hand is definitely not ideal.
The effects of this storm were more detrimental to the StarFire 3000 and 6000 receivers due to those models only having access to 2 satellite constellations. The StarFire 7000 and 7500s have access to 4 satellite constellations which allowed them to fight through these issues better, but they still lost accuracy. Upgrading to a StarFire 7000 or 7500 will provide an improvement, but is not a cure-all.
To be clear, this isn’t a problem with our RTK network. The RTK was affected more due to its ability to have more corrections and it is a higher accuracy system anyway. More corrections coming in that were “bad” created more inaccuracy than we saw in the other systems. The storm has affected all brands of GPS, not solely John Deere.
We are in search of tool to help predict this in the future so that we can attempt to give our customers an alert that this issue may be coming. We do believe this historic event and it isn’t something that we are going to have to continue to battle frequently.
When you head back into these fields to side dress, spray, cultivate, harvest, etc., over the next several months, we expect that the rows won't be where the AutoPath lines think they are. This will only affect the fields that are planted during times of reduced accuracy. It is most likely going to be difficult - if not impossible - to make AutoPath work in these fields as the inaccuracy is most likely inconsistent.
The entire team at LandMark is here to partner with you in this upcoming growing season as we work through this event together. We are committed to helping you find a solution to keep your operation running as smoothly and efficiently as possible. Again, we thank you for your patience as we work through this together.
Friday, May 10 - 6:30 p.m. Update:
Please be advised that there is significant solar flare and space weather activity currently affecting GPS and RTK networks. This severe geomagnetic storm is the worst since 2005 and is forecasted to continue throughout the weekend.
We have found that the best course of action at this time is to shut off RTK and use a grace period for SF2/SF3. This will eliminate the conflicting corrections that the machine is receiving from the base station due to the geomagnetic storm. GPS accuracy will still likely be reduced due to the storms.
We apologize for the inconvenience.
Friday, May 10 - 5:00 p.m. Update:
We are seeing GPS issues across our entire service area that are affecting RTK and all other levels of GPS. We are currently trying to determine a resolution.