Over-the-Horizon Backscatter Radar

Abstract

In FY 2024, PE 0102412F North Warning System (NWS) HLD-OTHR funds were realigned to PE 0102417F Over-the-Horizon Backscatter Radar to report all Department of the Air Force OTHR efforts in one R-1 line. Efforts funded in this PE focus on development, testing, and fielding, of a long-range early detection capability for airborne and surface targets of interest. Each line of effort acquires and fields a land based, high-frequency (HF) ionospheric backscatter radar for over the horizon detection and tracking of airborne and surface targets over wide geographic areas. Fielding of this capability will enable detection, tracking and reporting of airborne and surface targets that may be obscured from conventional line of sight radar systems by the curvature of the earth. Specific lines of effort funded include, but are not limited to, Tactical Multi-Mission Over the Horizon Radar (TACMOR), Homeland Defense Over the Horizon Radar (HLD-OTHR) and support for a classified EUCOM requirement. TACMOR capability is being developed for employment in the Republic of Palau (RoP) to provide enhanced Air Domain Awareness in the USINDOPACOM area of responsibility. TACMOR will be located in the RoP and operated by the United States in agreement with the RoP. Development, test and evaluation, and acquisition of the system and associated components will provide warfighters with the capability to close gaps in surveillance coverage in key regions of the Pacific area of interest to the United States and its Allies. The total cost of the TACMOR Middle Tier of Acquisition effort is 243.4 million, including RDT&E and procurement of prototype units. TACMOR is not fully funded across the Future Years Defense Program. The Department of the Air Force is assessing all options to address the funding shortfalls for MTA programs including additional funding in a future budget request, performance trades based on technical maturity, or transition to alternative pathways. HLD-OTHR efforts focus on the development, testing, and fielding of capabilities to extend current NWS surveillance of long-range early warning for North America in response to emerging threats. The primary mission of the new HLD-OTHR systems will be to provide long-range sensor coverage of potential air and cruise missile threats to North America, with secondary and tertiary capability against complex targets of interest (i.e, High Altitude Balloons) and maritime surface vessels and additional tasking as required. The system will be comprised of four OTHR systems and an Operational Control Center. HLD-OTHR data will be distributed and integrated into existing air, missile and maritime defense early warning networks, as applicable. This project will continue to focus investments to enhance capability for the Air and Cruise Missile Defense of the Homeland mission. The FY 2025 funding request was reduced by $1.647 million to account for the availability of prior year execution balances. This program element may include necessary civilian pay expenses required to manage, execute, and deliver weapon system capability. The use of such program funds would be in addition to the civilian pay expenses budgeted in PE 0605827F, 0605828F, 0605829F, 0605831F, 0605832F, 0605833F, 0605898F, 0606398F. In FY2023, $4.2M was expended for civilian pay expenses in this program element, and in FY2024, $4.3M is forecasted for civilian pay expenses in this program element. This program is in Budget Activity 7, Operational System Development because this budget activity includes development efforts to upgrade systems that have been fielded or have received approval for full rate production and anticipate production funding in the current or subsequent fiscal year This program is in Budget Activity 7, Operational System Development because this budget activity includes development efforts to upgrade systems that have been fielded or have received approval for full rate production and anticipate production funding in the current or subsequent fiscal year.

Document Details

• Document Type: R2 Budgetary Justification
• Publication Date: Oct 01, 2025
• Source ID: 0102417F_7_3600_PB_2025
• Change Summary Explanation: BPAC TACMOR Development provided $7.810 million in FY23 as an Omnibus Reprogramming source. Air Force internally realigned HLD OTHR $309.519M of Procurement and MILCON funding in FY25 to RDT&E to support the acquisition strategy.
• Service Agency Name: Air Force

Entities

Organizations

• United States Air Force

Tags

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