GPS failures are becoming more frequent: causes and dangers
Global navigation systems under pressure
Global aviation now uses four different satellite navigation systems:
- GPS (USA)
- Galileo (EU)
- Glonass (Russia)
- Beidou (China)
While several systems are usually used in parallel in commercial aviation, many companies rely on Private aircraft exclusively to the American GPS. The problem: Interference and manipulation often specifically affect the GPS signalso that pilots can get into critical situations.
Causes of GPS faults
Since the beginning of the Russian war against Ukraine, the situation has worsened considerably. Especially in Eastern Europe, the Baltic Sea region and parts of Poland, Romania and Bulgaria there are repeated reports of GPS interference. Russia deliberately operates Jammers (jamming) in Kaliningrad and St. Petersburg.
There are two main methods of GPS interference:
- Jamming (interference signals)
- Powerful jamming transmitters are used to superimpose the actual satellite signal.
- Consequence: GPS navigation fails completelythe device reports "no signal".
- Spoofing (manipulation of the position)
- Here, a jammer transmits Fake GPS signalswhich deceive the on-board unit.
- Consequence: The aircraft is "placed" in the wrong positionwhich is particularly dangerous when autopilots react to it.
What happens in the event of a GPS failure in the cockpit?
In modern cockpits, GPS-based systems not only take over the pure Navigationbut also many Additional functions. A GPS failure can therefore have serious consequences:
✈ Failure of the moving map: The position is no longer displayed.
✈ Malfunction of the autopilot: If this is GNSS-controlled, it can make incorrect course corrections.
✈ Missing anti-collision warning: Systems such as TCAS or ADS-B may be affected.
✈ No terrain warning: The warning systems for terrain (TAWS) and obstacles only work to a limited extent.
✈ Inaccurate wind display: Without GPS, there is often no precise calculation of the wind offset.
It becomes particularly critical if the pilot is focussing heavily on Glass cockpit technology leaves. These modern systems often require GPS signals - a failure can therefore paralyse a large number of navigation and assistance systems.
How should private pilots prepare for GPS failures?
1. regularly check the NOTAMs
Before taking to the air, pilots should take a look at the current aeronautical reports (NOTAMs) throw. Areas with possible GPS interference are noted there.
One example: The NOTAM B0541/24 already warns of GPS unreliability in north-east Germany:
📌 "GPS UNRELIABLE AND MAY BE NOT AVAILABLE IN EASTERN PART OF FIR EDWW".
2. use online tools for GPS monitoring
Up-to-date information on GPS disruptions is available on special platforms:
🔗 GPSJAM - Shows current jamming zones worldwide.
🔗 Flightradar24 GPS Jamming Map - A map with GPS disturbances in aviation.
🔗 OPS Group - Daily updates on global aviation risks.
3. have alternative navigation methods ready
Even if Classic radio navigation (VOR/NDB) is being used less and less, it can be a valuable aid in the event of a GPS failure.
📡 VOR & DME Navigation:
- Europe still has a dense network of VOR stations.
- Pilots should consider the use of VOR/DME in their flight planning.
🗺️ Maps even without GPS:
- The Moving map function does not work without GPSbut the card can of course still be used.
- It is therefore advisable, continuously synchronise the landscape with the map.
🧭 Classic course calculation with compass and clock:
- The Compass always works - even in the event of a GPS failure.
- The Navlog with courses and flight times should be updated regularly.
4. plan alternative approach procedures
For instrument flights (IFR) GPS-based approaches (LPV, LNAV/VNAV) can no longer be used in the event of a failure.
Pilots should therefore ensure that they:
✅ Be able to select an alternative approach without GPS (e.g. ILS or VOR).
✅ Inform air traffic control of the cancellation.
✅ Be guided to the runway by radar vectors or radio navigation.
5. use additional technology on board
Interestingly enough Tablets and smartphones often less affected by GPS interference as certified aviation systems.
Why?
📌 Tablets and smartphones usually use several GNSS systems simultaneously (GPS, Glonass, Galileo).
📌 Certified avionics require higher signal quality and are therefore more sensitive.
🔹 Apps such as "NaviGuard" (from APG) recognise GPS faults and help with alternative navigation.
Conclusion: GPS failures are the new normal - preparation is key
GPS has become an indispensable part of modern aviation, but it remains vulnerable to Malfunctions and manipulations. Especially through the use of Jamming and spoofing in crisis areas incidents are becoming more frequent, which also have an impact on general aviation.
What should pilots do?
✅ Plan flights so that they are not dependent on GPS.
✅ Master classic navigation methods such as VOR/DME or map synchronisation.
✅ Use online tools to check for current GPS faults.
✅ Find out about alternative approach procedures.
✅ have tablets/smartphones on board as an additional navigation aid.
Source references:
Aviation magazine