Iran jams GPS on ships in Strait of Hormuz

August 9, 2019  - By

Ships sailing through the Strait of Hormuz and the Persian Gulf have been experiencing GPS interference that U.S. officials suspect is the work of the Iranians, according to CNN.

The U.S. Department of Transportation’s Maritime Administration issued an advisory on Aug. 7 to ships traveling in the Persian Gulf, Strait of Hormuz, Gulf of Oman, Arabian Sea and Red Sea. Ships have reported GPS interference, bridge-to-bridge communications spoofing and jamming, and other problems.

Iran’s goal is for ships and aircraft to wander into Iranian waters or airspace, justifying a seizure, a U.S. defense official told CNN. He said Iran has placed GPS jammers on Iran-controlled Abu Musa Island, which lies in the Persian Gulf close to the entrance of the Strait of Hormuz.

“Heightened military activity and increased political tensions in this region continue to pose serious threats to commercial vessels,” reads the advisory. “Associated with these threats is a potential for miscalculation or misidentification that could lead to aggressive actions. Vessels operating in the Persian Gulf, Strait of Hormuz, and Gulf of Oman may also encounter GPS interference, bridge-to-bridge communications spoofing, and/or other communications jamming with little to no warning.”

In at least two incidents, vessels reported GPS interference. One vessel reportedly shut off its Automatic Identification System (AIS) before it was seized, complicating response efforts.

Vessels have also reported spoofed bridge-to-bridge communications from unknown entities falsely claiming to be U.S. or coalition warships.

Since May 2019, the following maritime incidents have occurred in this region:

  • Six attacks against commercial vessels.
  • Shoot-down of U.S. Navy remotely piloted aircraft over international waters
  • Attempted at-sea interdiction of Isle of Man-flagged M/V British Heritage (oil tanker)
  • Seizure of ex-Panama-flagged M/V Riah (oil tanker)
  • Seizure of U.K.-flagged M/V Stena Impero (oil/chemical tanker)
  • Detention and subsequent release of Liberian-flagged M/V Mesdar (oil tanker).
Photo: Igor Grochev/

Photo: Igor Grochev/

About the Author: Tracy Cozzens

Senior Editor Tracy Cozzens joined GPS World magazine in 2006. She also is editor of GPS World’s newsletters and the sister website Geospatial Solutions. She has worked in government, for non-profits, and in corporate communications, editing a variety of publications for audiences ranging from federal government contractors to teachers.