Navy asks Raytheon to support ROTHR over-the-horizon surveillance radar system to monitor drug smuggling

March 1, 2021
ROTHR works with HF radar waves that bounce off the ionosphere to provide long-range over-the-horizon radar coverage, similarly to shortwave radio.

PHILADELPHIA – Long-range radar experts at Raytheon Technologies Corp. will continue to operate a U.S. Navy surveillance system designed to detect and track aircraft and surface ships all over the Caribbean from the Florida Coast to South America.

Officials of the Naval Supply Systems Command Fleet Logistics Center, Norfolk, Contracting Department, Philadelphia Office in Philadelphia announced a potential five-year $146.3 million contract to the Raytheon Intelligence & Space segment in Sterling, Va., to support the relocatable over-the-horizon radar at the Forces Surveillance Support Center in Chesapeake, Va.

The ROTHR over-the-horizon radar uses high-frequency radar waves that bounce off a layer of the atmosphere called the ionosphere to provide long-range over-the-horizon radar coverage. It achieves long ranges just like shortwave radio.

ROTHR uses high-frequency (HF) radio waves, which are particularly susceptible to interference from lightning almost anywhere in the world. HF signal reception also changes throughout the course of the day and the seasons, as well as at night, so ROTHR poses a particularly difficult digital signal processing (DSP) problem.

Related: Navy asks Raytheon to operate and maintain ROTHR over-the-horizon surveillance radar

ROTHR is designed to provide early warning of strikes against aircraft carrier task forces, and is suited especially for long-range surveillance of large open-water areas out to ranges as far as 2,500 nautical miles.

The U.S. Navy operates two ROTHR systems, one in Chesapeake, Va., and the other in Corpus Christi, Texas. Together, these radar systems cover most of the Caribbean, and extend into the Pacific coat of Central America and South America as far south as the Galapagos Islands.

As their name implies, the ROTHR systems can be moved, and have been redeployed for detection and monitoring of air traffic in the U.S. government's war against drugs, Raytheon officials say.

Related: Radar technology looks to the future

The ROTHR system has been operational with the U.S. government for more than 25 years, supporting the counter drug mission in the Caribbean and South America, and early warning detection for Navy vessels at sea.

ROTHR originally was developed to keep long-range watch for cruise missiles and other low-flying threats to the U.S. mainland well offshore. Eventually ROTHR took over monitoring drug smuggling in the Caribbean.

The radar provides more than 2.5 million square miles of coverage and detects more than 350,000 targets per year. It is currently the U.S. government's primary surveillance system for the counter-drug mission, Raytheon officials say.

Related: Aerostat-based over the horizon radar for cruise missile defense demonstrated by Raytheon

Raytheon has been upgrading the radars since the initial installations to improve performance and reliability. Performance improvements included state of the art computers and displays and enhanced software for more accurate tracking of small aircraft and boats.

On this contract Raytheon will do the work in Chesapeake, New Kent, and Fairfax, Va.; Freer, Premont, and Dallas, Texas; and in Juana Diaz and Vieques, Puerto Rico, and with options should be finished by April 2026.

For more information contact Raytheon Intelligence & Space online at, or the Naval Supply Systems Command Fleet Logistics Center at

About the Author

John Keller | Editor-in-Chief

John Keller is the Editor-in-Chief, Military & Aerospace Electronics Magazine--provides extensive coverage and analysis of enabling electronics and optoelectronic technologies in military, space and commercial aviation applications. John has been a member of the Military & Aerospace Electronics staff since 1989 and chief editor since 1995.

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