The United States utilizes radar systems for various domestic missions. These systems create the backbone of our nation’s defense, air traffic control (ATC), and weather detection capabilities. While these systems adequately accomplish the mission at hand, they are beginning to age, are prone to outages, and do not employ radio frequency spectrum efficient technologies that have been developed since their deployment. Concurrently, the world has seen an increase in consumer demand for wireless connectivity and broadband data. Emerging commercial technologies such as 5G networks, internet of things, and satellite internet constellations are being developed and deployed to satisfy these consumer needs. This increase in wireless coverage and capacity comes with a price of increased demand for spectrum. The Department of Defense supports a program that seeks to update domestic radar systems and facilitate the deployment of the latest commercial technologies.
Spectrum is a finite resource. To accommodate and encourage emerging technologies while protecting federal system operations, both government and industry are looking at options to either share or auction federal spectrum for commercial use. The Spectrum Pipeline Act of 2015 requires the Federal Communications Commission (industry representative) and the National Telecommunications and Information Administration (federal agency representative) to identify 30 MHz of spectrum under 3 GHz to either auction to nonfederal entities, share usage, or implement a combination of both approaches by July 2024. To accomplish this requirement, federal agencies are studying the feasibility of auctioning at least 30 MHz of spectrum in the 1300-1350 MHz federal band.
The Spectrum Efficient National Surveillance Radar (SENSR) program, led by The Federal Aviation Administration, and supported by the DoD and Department of Homeland Security, is taking steps to allow mobile broadband 5G operations in the 1300-1350MHz band. To accomplish this federal long-range surveillance and ATC radars currently operating in the 1300-1350 MHz band will be updated into the new SENSR radar system and relocated to other frequency band(s).
Federal agencies will work with industry to develop the SENSR system, which will feature either a single radar system to support multiple missions or a system of systems architecture. The systems of systems architecture makes use of multiple radar systems performing different missions that are interconnected using a standardized communication format working together as one system. Some examples of possible SENSR missions are long-range/short-range/near-range surveillance, air traffic control, and weather detection. SENSR will utilize updated spectrum efficient technology and techniques, allowing the radar to accomplish the required missions with a smaller overall spectrum footprint. Figure 1 illustrates the possible missions under the SENSR system.
The DON is providing support for acquisition activities, development of system requirements, and feasibility studies related to deploying 5G systems in the 1300-1350 MHz band. As noted below, in addition to studying the compatibility of 5G systems with other non-radar systems in the 1300-1350 MHz band. Feasibility studies must also address the compatibility of SENSR and other DoD non-radar systems relocated to other bands with incumbent systems operating in those bands.
There are currently two separate spectrum related feasibility efforts. One study will determine if 5G systems moving into the 1300-1350 MHz band can coexist with the DoD non-radar tactical, test, and training systems operating there. This study includes identifying any mitigation techniques required. If coexistence is not possible, the study will determine the feasibility of relocating those non-radar systems to another frequency band. Once potential band(s) are identified for SENSR, the other study will determine if the SENSR system(s) can coexist with incumbent systems operating there.
Since the specific operating frequency range of the SENSR components will be open-ended, industry developers have control on the types of technologies utilized to accomplish the new SENSR systems’ mission. However, this open-ended methodology could create challenges for the DON. Because SENSR may deploy in multiple frequency bands, the DON must consider the various types of incumbent radars in those bands to determine if those systems will need modifications to coexist with SENSR radar components.
Demand for wireless connectivity will continue to increase as new technologies enable enhanced products, systems, and services. To best meet national mission requirements of both commercial and federal entities, proposed spectrum reallocation impact must be thoroughly studied; spectrum efficient technologies must be deployed; and reliable spectrum sharing techniques must be developed.
The SENSR program aims to accomplish these objectives to help clear the path for commercial 5G and other emerging technologies while providing more efficient and effective domestic federal spectrum usage.
Joseph Crossin works for The Aerospace Corporation and is a member of the Department of the Navy SENSR Team.