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Dec 12 2019

GPS interference and possible jamming with potentially dangerous consequences is reportedly occurring in the Eastern Mediterranean in vicinity of Cyprus and the entrance to the Suez Canal since the beginning of 2018.  

However, since the second quarter of this year, similar observations of GPS interference and possible jamming were also received from vessels and aircraft operating in the Central Mediterranean. In the area bounded by Malta – Zuwarah (Libya) – Misratah (Libya), vessels and aircraft reported loss of GNSS (GPS/ GLONASS) signal, incorrect locations and interrupted reception of signal. This often affected other on board systems requiring GPS timing or positioning, such as (Satellite-) Communication and (weather-) Radar.


 On 24 SEP 19, the U.S. Maritime Administration issued a new Maritime Alert, MARAD 2019-013, now including GPS Interference in both the Eastern Mediterranean and Central Mediterranean. Multiple sources can cause GPS interference, including radio emissions in nearby bands, intentional or unintentional jamming, and weather conditions. The impact and origin of this interference is still under investigation, but it is likely vessels will and should adopt reversionary modes such as Radar, Chart, and Visual data to account for loss of GPS / GLONASS or inaccuracies encountered. While less effect in open waters, the impact may be felt more during confined navigational movement, or while entering port due to the increased workload on bridge teams.


We have also noted reports from both the Eastern Mediterranean and Central Mediterranean that ships are suppressing their static AIS data (name, next port of call, etc.) and switching to “receive only.” Whilst there may be valid reasons for masters doing this, overall it means a loss of situational awareness in the area. Commercial vessels operating in the MED are likely to receive special attention by warships in the region if adopting this practice. Ships should expect to be queried to ascertain why AIS is off or switched to inhibit. AIS suppression is a ploy often used by vessels to hide suspicious movement, therefore we advise against this practice.


It is recommended to prepare the crew for navigation using alternative methods to GPS / GLONASS. The problem could be mitigated by using anti-jamming GPS antenna that only point to the sky in order to make it more difficult to receive jamming by the land. 
Reporting. The NSC, in cooperation with the U.S. MARAD, continues to encourage all ships to report incidents of GPS jamming or other interference (i.e.use of false AIS, rogue GSM-towers).

A format to report interference, reactions taken, and the overall impact (if any) is available on the NSC’s website The NSC will continue to share the reports and findings with U.S. MARAD and update our website with the latest info. Any other incident reporting can be done on the NATO Shipping Website at For faster reporting, Email or phone our 24/7 Duty Officer at or +44 (0) 1923 956574.


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