How Space Weather Affects GPS, RTK, and Survey Accuracy
Understanding why solar activity degrades GNSS positioning — and what it means for drone pilots and surveyors
Overview
Space weather — including solar flares, geomagnetic storms, and ionospheric disturbances — directly affects the accuracy and reliability of GPS and other GNSS systems. The most common impact is on the signals themselves: they must travel through Earth's ionosphere, which becomes unstable during solar activity. In extreme events, high-energy particles can also directly affect satellite electronics through radiation damage and single-event upsets.
For drone pilots and surveyors, this can mean degraded RTK performance, increased positioning error, loss of FIX solutions, or longer convergence times for PPP and static surveys.
The Key Problem: The Ionosphere
The ionosphere is a region of the upper atmosphere filled with charged particles created by solar radiation. GNSS signals must pass through it before reaching Earth's surface.
When solar activity increases, the ionosphere becomes turbulent and irregular. This introduces errors that GNSS correction systems cannot always fully compensate for.
Primary effects include:
- Increased signal delay
- Rapid signal fluctuations (scintillation)
- Loss of signal lock (cycle slips)
- Reduced satellite availability
How This Impacts GPS & GNSS Signals
GNSS positioning depends on extremely precise timing. Even tiny delays in signal travel time translate into measurable position errors.
During geomagnetic storms:
| Effect | What Happens | Operational Impact |
|---|---|---|
| Ionospheric Delay | Signal slows unevenly | Increased position error |
| Scintillation | Rapid signal fading | Receiver loses lock |
| Cycle Slips | Phase tracking breaks | RTK solution resets |
| Satellite Geometry Changes | Some signals unusable | Reduced accuracy |
Why RTK Breaks First
RTK systems depend on extremely stable carrier-phase tracking. Ionospheric disturbances cause rapid phase changes that the receiver cannot model correctly.
This leads to:
- FIX → FLOAT transitions
- Longer initialization times
- Loss of integer ambiguity resolution
Effects on Drone Operations
Drone mapping missions depend on consistent RTK performance for accurate georeferencing.
During high space weather activity, operators may experience:
- Mapping datasets with variable accuracy
- GCP mismatches
- Repeated RTK resets
- Increased post-processing corrections
Effects on Surveying & Static GNSS
Long-duration static surveys are more stable than RTK but still affected:
- PPP convergence times increase
- OPUS solutions — especially OPUS-RS (Rapid Static) — may fail or take longer
- Baseline repeatability decreases
Solar Flares vs Geomagnetic Storms
| Event Type | What It Does | GNSS Impact |
|---|---|---|
| Solar Flare | X-ray burst increases ionization instantly | Short-term signal degradation |
| Geomagnetic Storm | CME interacts with Earth's magnetic field | Widespread ionospheric disruption |
| Radio Blackout | HF comms disrupted | GNSS degraded at moderate levels (R1–R3); R4–R5 events can cause significant outages |
Key Takeaways for GNSS Professionals
- Space weather primarily distorts the medium signals travel through — though extreme events can also affect satellite hardware directly
- RTK systems are most vulnerable
- Static GNSS is more resilient but slower to stabilize
- Monitoring space weather is part of mission planning