The U.S. Army is amidst a multi-faceted effort to field a mobile battlefield network simultaneously modular, open, and secure from interference from enemy electronic warfare systems.
A significant part of that network, for ground troops, combat vehicles, command posts, and aviation assets, are software-defined radios built with open architectures that allow for rapid adaptation to enemy capabilities and efficient introduction of emerging technologies.
Standardized radio hardware that can be readily upgraded with new waveforms will allow U.S. forces to communicate among services within the in-development Joint All-Domain Command-and-Control environment (JADC2). Running multiple waveforms at once will allow U.S. troops, aircraft, and vehicles to emit and receive audio, video, and data without being spied on by opposition forces.
Russia’s war on Ukraine underscores the need for secure, multi-waveform battlefield communications. Ukrainian forces routinely target radio transmissions from commercial-grade radios and cell phone calls used by poorly trained and equipped Russian soldiers. Maj. Gen. Jeth B. Rey, director of the Network Cross-Functional Team within Army Futures Command, said the war in Ukraine validates the Army’s pursuit of secure communications capabilities.
“What we are seeing in Ukraine reinforces the need for secure communications and greater mobility and survivability,” Rey told the Armed Forces Communications & Electronics Association International (AFCEA) in a Q&A published in November. “There is also great innovation occurring with our soldiers who are supporting operations in Europe.”
Fielding secure communications technologies to large-scale military formations, installing them in thousands of vehicles and aircraft, and training soldiers to use them is hampered by the pace of technological innovation, Rey said. Following traditional Defense Department development and procurement pathways, through which a specific radio or waveform may take years to perfect and field, cannot keep up with the speed at which digital technologies emerge, Rey said.
“The network will always face challenges with the rapid evolution of commercial technology and how we can adapt it to military requirements and scale it appropriately across different elements of the Army,” Rey told AFECA. “Based on recent observations, the primary challenges to achieving network modernization supporting the Army of 2030 are fielding velocity—the pace of delivering new equipment to the force—and alignment of capabilities across echelons.”
Rey mentioned JADC2 as a “critical capability” based on a data-centric tactical data fabric. In 2023, the Army is focused on establishing its so-called network capability set 23, or CS23, which will align more than 40 individual communications systems ranging from handheld soldier radios to communications satellites and software-defined network operation systems into a single system that should boost overall security and capability. CS23 will introduce high-bandwidth satellite communication through commercial services while integrating EW, intelligence, targeting, and fire control capabilities into the system while easing sustainment, Rey said.
At the heart of those technologies are software-defined radios that feature reconfigurable, open-architecture hardware and software capable of digitally processing data. Software-defined radios can tune to any frequency band and use multiple waveforms through plug-and-play software applications built to published Army standards.
Mike Shepherd, who leads the FlexLink radio program at Collins Aerospace, now owned by Raytheon, said the Army wants to boost competition for communication software by establishing hardware architecture standards into which more and smaller companies can plug their applications and waveforms.
Aside from Raytheon, more than a dozen major defense and communications companies are working to develop SDR hardware, software, or both. They include Elbit Systems, L3 Harris, BAE Systems, General Dynamics, Thales, German firm Rohde & Schwarz, Chinese telecom giant Huawei, and Texas Instruments, to name several.
Shepherd said the Army intends to level the playing field not just for prime defense contractors but for smaller, more agile companies that may have unique waveforms or applications that could provide an operational advantage. Flexible, rapidly reconfigurable SDRs also boost capability without weighing down vehicles and taking up as much space as traditional communication equipment, Shepherd said. The real bargain is the balance between their ability and the size, weight, and power, or SWAP, they require of an aircraft, he said.
“If you've been on an Army vehicle lately, there's a lot of equipment, a lot of boxes,” Shepherd told Avionics in a recent interview. “So many boxes we call it ‘boxology,’ and it’s all new hardware. The software allows you to get multiple waveforms on a card. Army Aviation needs more waveforms than ground vehicles, for example, because they're doing air-to-air communications, air-to-space, and air-to-ground. The ground guys, by and large, don't need all that. So, it allows for mobility. It levels the playing field. It allows other smaller companies to play, not necessarily the big primes. They can provide a unique waveform, or they provide a card. So it's really, big picture, adding capability and being flexible and lowering costs and adapting to emerging threats.”
“The services, particularly in the Army because they're pretty active, have made it very clear,” Shepherd added. “No one company is going to build it all, whether it's the chassis, the cabling, cards, or software. They really want to level the playing field so that multiple suppliers can participate.”
The U.S. Army is engaging industry to create a reference architecture to establish parameters and how the industry may collectively begin to develop communications technologies that meet them. Multiple Cross-Functional Teams within Army Future’s Command besides Rey’s network CFT are working on the issue.
The network CFT at Aberdeen Proving Ground led by Gen. Rey is one. It is joined by the Future Vertical Lift CFT based at Redstone Arsenal in Alabama, the Precision Navigation and Timing CFT also at Redstone, and the Next-Generation Combat Vehicle FCT at the Detroit Arsenal.
The Army published a reference architecture RFI last year. Another final solicitation is expected in March, Shepherd said. Any open architecture approach to communications equipment development will only work if all the services comply so that they can communicate and share technology and data across the Air Force, Army, and Navy, he said.
During the Army's Project Convergence exercise late last year, Raytheon recently demonstrated several solutions to connect defense networks and simplify U.S. Army command-and-control systems. Among those technologies was FlexLink, an open-system radio technology developed by its Collins subsidiary, designed to connect multiple air and ground platforms.
During the exercise, FlexLink was installed on Army UH-60M helicopters and established a joint command-and-control network at distances exceeding 200 nautical miles, validating the Army’s contribution to the multi-service JADC2 network.
The demonstration integrated the first open-systems radio onto a legacy Black Hawk helicopter, which has been burdened with Shepherd’s “boxology” for decades as new technologies were bolted onto an airframe first fielded in 1979. Size, weight, and power are less of an issue with the Army’s new Future Long Range Assault Aircraft (FLRAA) and Future Attack Recon Aircraft (FARA), both of which are being developed with open architecture systems from the get-go. Shepherd said that the Army must run 11 simultaneous communication waveforms hosted on multiple SDR cards for those aircraft. The only way to achieve such a broad communication spectrum is with software-defined radios like FlexLink, he said.
Other services are equally interested in the flexibility and capability provided by SDRs. Boeing is integrating Rohde & Schwarz MR6000R multiband-capable airborne transceivers from the SOVERON software-defined radio family on the Air Force’s new T-7A Red Hawk pilot trainer. Weighing less than 9 pounds (4 kilograms), the MR6000R meets the SWAP requirements for the jet, of which the Air Force has ordered 351 to replace its 57-year-old fleet of T-38C Talons. It covers the frequency range from 30 MHz to 400 MHz and supports the NATO frequency algorithms HAVE QUICK II for interoperability and digital fast frequency hopping standard SATURN, according to Rohde & Schwarz.
“Along with updated technology and performance capabilities, the T-7A will be fitted with an enhanced radio communications suite, giving it an added benefit, preparing pilots for fifth-generation aircraft,” Michael Hostetter, vice president of Boeing Defense & Space, Germany, said in a statement.
Frank Dunn, President and CEO of Rohde & Schwarz USA (and Canada), said, “the airborne transceivers from the SOVERON radio family provide excellent RF characteristics suitable for applications in harsh military environments for all types of airborne platforms. As this is a software-defined radio, we can adapt it for further training opportunities.”
Rohde & Schwarz also recently delivered the 1000th AN/ARC-238 software-defined radio (SDR) to Lockheed Martin for integration on F-16 aircraft. The AN/ARC-238 consists of two airborne radios from the SOVERON radio family, namely the R&S MR6000R/L radios, and meets specific communication requirements while fully qualified on the F-16.
“To reach this milestone is a great privilege and showcases our team’s ability to continuously produce and distribute high-quality software-defined airborne radios in support of the F-16,” says Stefan Pleyer, vice president of the avionics market segment at Rohde & Schwarz. “I am confident that our SOVERON radios make the F-16 even more efficient. We are proud to work with Lockheed Martin, delivering the 1000th SDR.”
These are by no means the only military applications for SDRs. Thales, for instance, offers a wide range of open-system communication devices but is focused primarily on tactical radios for ground troops. It recently won a contract to provide combat network radios based on the AN/PRC-148 Joint Tactical Radio System Enhanced Multiband Inter/Intra Team Radio (IMBITR) that will be compatible with existing but outdated waveforms while allowing the Army to add new waveforms and enhanced capabilities to address evolving requirements.
As the U.S. military begins fielding JADC2 and its component communications technology, software-defined radios will be vital to keeping the network relevant as technology and threats evolve. Expect to see the rapid integration of new software capabilities, applications, and technology once the system comes online. That should also provide the communications industry, from top to bottom, an open door to doing business with the Defense Department.
