Article By Jodi Boe
Farmers hoping to take advantage of a dry weekend for planting were met with a frustrating surprise: inoperable GPS guidance systems. The culprit? Powerful solar flares erupting from the sun.
Our sun goes through an 11-year cycle of activity, with the current cycle peaking right now. This peak brings increased solar activity, including sunspots and flares. A particularly strong flare on May 10th, 2024 the largest of this cycle, caused significant disruption to GPS signals.
GPS relies on satellites orbiting Earth that transmit signals to receivers on the ground. These signals travel through the Earth’s atmosphere, including the ionosphere. When a solar flare hits the Earth’s atmosphere, it energizes particles in the ionosphere, causing them to disrupt the path of GPS signals. This disrupts the calculations receivers make to determine location, rendering them inaccurate or unusable.
Photo source: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk-Keith
While the effects of the solar storm were temporary, they highlight the vulnerability of GPS to space weather events. While some correction systems exist, like WAAS (Wide Area Augmentation System) and RTK (real-time kinematic positioning), they can also be affected by strong solar flares, such as we saw during the May 10th solar storm.
Additional resources:
GNSS Basics https://www.youtube.com/watch?v=ktf9CLNVLg8
Trimble’s GNSS Planning Online: https://www.gnssplanning.com/#/settings