This revised advisory cancels U.S. Maritime Advisory 2020-016

1. Reference: None.

2. Issue: Multiple instances of significant GPS interference have been reported worldwide in the maritime domain. This interference is resulting in lost or inaccurate GPS signals affecting bridge navigation, GPS-based timing, and communications equipment. Satellite communications equipment may also be impacted. Over the last six months, areas from which multiple instances have been reported include the eastern and central Mediterranean Sea, the Persian Gulf, and in the vicinity of the Suez Canal. The U.S. Coast Guard Navigation Center (NAVCEN) web page, go.usa.gov/xs6xa, contains a chronological list of recently reported GPS problems.

3. Guidance: Exercise caution when underway and prior to getting underway. The NAVCEN and NATO Shipping Center websites contain information regarding effective navigation practices for vessels experiencing GPS disruption. The information reaffirms safe navigation practices when experiencing GPS disruptions, provides useful details on reporting disruptions, and is intended to generate further discussion within the maritime community about other disruption mitigation practices and procedures. This guidance also recommends reporting such incidents in real time; noting critical information such as the location (latitude/longitude), date, time, and duration of the outage/disruption; and providing photographs or screen shots of equipment failures experienced to facilitate analysis. The NAVCEN information is available at: https://go.usa.gov/xQBaU.

4. Contact Information: Maritime GPS disruptions or anomalies should be reported immediately to the NAVCEN at https://go.usa.gov/xQBaw or via phone at 703-313-5900, 24-hours a day. NAVCEN will further disseminate reported instances of GPS interference in this region to the NATO Shipping Center.

5. Cancellation: This message will automatically expire on September 15, 2021.

For more information about U.S. Maritime Alerts and Advisories, including subscription details, please visit https://www.marad.dot.gov/MSCI.