U.S. Navy Extends ROTHR Long-Range Radar to 2031 with $212M Raytheon Sustainment Contract.

Raytheon has secured a U.S. Navy contract worth up to $212.12 million to sustain the AN/TPS-71 ROTHR radar network covering the Caribbean and Gulf of Mexico through 2031. The award ensures continued long-range detection of air and maritime threats across the southern approaches, a critical gap area for U.S. homeland security and counter-trafficking missions.

Raytheon has secured a new Navy sustainment contract that keeps the AN/TPS-71 Relocatable Over-the-Horizon Radar watching the Caribbean, Gulf of Mexico, and the wider southern approaches to the United States, preserving one of Washington’s few persistent long-range wide-area surveillance layers for air and maritime detection. The award is worth $40.25 million for the base year and can reach $212.12 million if four option years are exercised, extending performance to April 2031. Announced in the Pentagon’s March 16 contract release, the deal is formally for operations and maintenance, but in capability terms it is a readiness contract for a national sensor network that U.S. Southern Command has described as its only persistent long-range aerial coverage for the southern approaches.

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Raytheon’s new Navy sustainment contract keeps the AN/TPS-71 Relocatable Over-the-Horizon Radar operational, preserving a long-range surveillance capability that helps the United States monitor air and maritime activity across the Caribbean, Gulf of Mexico, and southern approaches (Picture source: U.S. DoW).

ROTHR remains a distinctive radar in the U.S. inventory because it is not a conventional line-of-sight microwave system. The AN/TPS-71 is a land-based, high-frequency skywave radar that uses 5 to 28 MHz energy refracted by the ionosphere to illuminate targets far beyond the horizon, covering a 64-degree wedge at ranges of roughly 500 to 1,600 nautical miles. The Virginia sector alone has been described as surveying more than 2.2 million square miles. The network is organized around an operations control center in Chesapeake and three land-based bistatic Doppler radar sectors in Virginia, Texas, and Puerto Rico, with separate transmit and receive sites across the locations listed in the contract, including Chesapeake, New Kent, Freer, Premont, Juana Diaz, and Vieques.

The radar’s architecture explains why it is still operationally relevant. Each ROTHR receiver uses a 2.58-kilometer linear phased array of 372 twin-monopole elements, each paired with a receiver and analog-to-digital converter. A digital beamformer creates 18 beams, and Doppler processing helps separate moving aircraft or vessels from intense ground and sea clutter. Range resolution comes from a 25-kHz continuous frequency-modulated waveform, producing a surface resolution cell of roughly 6 kilometers in range by about 15 kilometers in azimuth under the conditions cited in technical descriptions. That does not make ROTHR a precision engagement radar, but it does make it a highly efficient wide-area detection and cuing sensor, exactly the kind of system needed to find sparse moving targets across enormous oceanic and littoral spaces.

Operationally and tactically, that matters because the system is built to do first detection, persistence, and handoff rather than final interception. Joint Interagency Task Force South’s mission is to detect and monitor illicit trafficking across domains and facilitate interdiction, and ROTHR gives that mission a broad-area radar tripwire that can spot suspicious air and maritime movement early enough to vector aircraft, cutters, or partner-nation assets onto the track. The radar is not perfect. GAO has previously noted that relocatable over-the-horizon radar does not provide altitude or exact target location, which makes downstream localization harder. But that limitation does not diminish its value. In practice, ROTHR compresses a huge search problem into a manageable one, allowing scarce interceptors and patrol assets to be used where the probability of contact is highest.

That is why this radar matters to the United States beyond its traditional counterdrug framing. ROTHR provides strategic depth at a fraction of the cost of maintaining continuous airborne patrols, and the Naval Research Laboratory has characterized HF over-the-horizon radar as the most cost-effective wide-area sensor available. Its lineage reaches back to NRL’s pioneering MADRE system and decades of U.S. work on exploiting ionospheric propagation for long-range warning. In today’s environment, that translates into a persistent homeland security and maritime domain awareness tool that can illuminate irregular air and surface traffic without consuming high-demand aircraft every hour of the day. It also explains why Raytheon is using its ROTHR experience as the foundation for next-generation OTH radar work tied to cruise missile warning and homeland defense architectures.

The contract is also important because it funds the mission-critical work that actually keeps a rare radar network alive. Government descriptions tied to the ROTHR support requirement include day-to-day operation of the operations control center and communications infrastructure, preventive and corrective maintenance of the radar and its subsystems, repair of transmit and receive HF antenna arrays and shelters, upkeep of air conditioning, electrical and fire-suppression systems, replacement of UPS and battery systems and cesium tubes, relay and antenna refurbishment, and technical engineering support for electrical and antenna systems. This sustainment layer sits alongside a separate June 2023 Navy contract, valued at $87.5 million, for software enhancements, software re-hosts, integration, testing, logistics, and engineering support through 2027. Together, the two efforts show the Navy is not merely keeping ROTHR on life support, but actively preserving and updating a specialized surveillance enterprise.

For the U.S. defense industrial base, the award also signals continuity in a niche sector where there are very few qualified performers. The Pentagon said the competition was run through SAM.gov and drew only one offer, a reminder that over-the-horizon radar operations combine rare HF radar engineering, site maintenance, software support, and an experienced operator cadre. With SOUTHCOM warning that encroachment, such as wind farm development, must not degrade ROTHR mission performance, and with Raytheon carrying more than 30 years of OTH radar integration and sustainment experience, the Navy’s decision is less about routine service contracting than about protecting an irreplaceable surveillance capability. This contract preserves a technically unique sensor that still gives U.S. commanders broad-area awareness across a strategically exposed arc where persistent detection remains hard, expensive, and operationally decisive.