Tag Archives: DARPA

Einstein Box

Lockheed Martin Skunk Works and the Defense Advanced Research Projects Agency (DARPA) recently performed a series of flight tests demonstrating how a System of Systems (SoS) approach enables seamless – and rapid – integration across air, space, land, sea and cyber in contested environments.

DARPA, Lockheed Martin demonstrates technologies to enable a connected warfighter network
DARPA, Lockheed Martin demonstrates technologies to enable a connected warfighter network

The demonstrations held at the Naval Air Warfare Center in China Lake, California, were part of a five-year DARPA program called System of Systems Integration Technology and Experimentation (SoSITE). The flight tests demonstrated interoperability between a ground station, flying test bed, a C-12 and flight test aircraft, and proved the ability to transmit data between those systems using STITCHES, a novel integration technology.

The test used the Skunk Works developed Enterprise Open System Architecture Mission Computer version 2 (EMC2), known as the «Einstein Box», as the open computing environment, providing security protections between systems. The Einstein Box enables rapid and secure experimentation before deploying the capability to operational systems. The team successfully demonstrated four key capabilities:

  • The ability to automatically compose and transmit messages between systems, including those using legacy datalinks;
  • The first use of Non-Enterprise Data Links to create new, rich information exchanges in-flight through Link-16, enabling greater speed, agility, modernization and effectiveness;
  • The ability to link ground-based cockpit simulators with live aircraft systems in real time to demonstrate how a SoS approach reduces the data-to-decision timeline;
  • Integration between the APG-81 radar, currently used on the F-35, and DARPA’s Automatic Target Recognition software to reduce operator workload and to create a comprehensive picture of the battlespace.

Demonstrating rapid and affordable integration of mission systems into existing and new architectures, SoSITE will help U.S. forces maintain their advantage in today’s dynamic world.

«The successful demonstrations focused on advancing integration technologies to increase capabilities of systems in operation today, enabling our warfighters to use those systems in unexpected ways», said Justin Taylor, Lockheed Martin Skunk Works Mission Systems Roadmaps director. «The SoS approach is essential for allowing U.S. forces to rapidly reconfigure systems and prevail over any threat».

The project was led by Lockheed Martin Skunk Works in partnership with the U.S. Air Force and support from industry partners Apogee Research, Northrop Grumman, Lockheed Martin Missiles and Fire Control, BAE Systems, Phoenix Flight Test, General Dynamics and Rockwell Collins.

Skunk Works’ expertise in open system architecture spans more than a decade. The success of SoSITE is a critical step to enabling multi-domain operations and maintaining superiority in the future battlespace. In its 75th year, Lockheed Martin Skunk Works is proud to advance SoS integration in partnership with DARPA as they celebrate 60 years of creating breakthrough technologies and capabilities for national security.

Future combat vehicles

DARPA’s Ground X-Vehicle Technologies (GXV-T) program aims to improve mobility, survivability, safety, and effectiveness of future combat vehicles without piling on armor. Several Phase 2 contract awardees recently demonstrated advances on a variety of potentially groundbreaking technologies to meet the program’s goals.

GXV-T advances radical technology for future combat vehicles
GXV-T advances radical technology for future combat vehicles

«We’re looking at how to enhance survivability by buttoning up the cockpit and augmenting the crew through driver-assistance aids», said Major Amber Walker, the program manager for GXV-T in DARPA’s Tactical Technology Office. «For mobility, we’ve taken a radically different approach by avoiding armor and developing options to move quickly and be agile over all terrain».

Demonstrations, such as one in May at Aberdeen Test Center, have given potential military service transition partners an opportunity to observe technical progress on the GXV-T program, including:

 

Radically Enhanced Mobility

GXV-T envisions future combat vehicles that could traverse up to 95 percent of off-road terrain, including slopes and various elevations. Capabilities include revolutionary wheel-to-track and suspension technologies that would enable access and faster travel both on- and off-road, compared to existing ground vehicles.

Reconfigurable Wheel-Track (RWT)

Wheels permit fast travel on hard surfaces while tracks perform better on soft surfaces. A team from Carnegie Mellon University National Robotics Engineering Center (CMU NREC) demonstrated shape-shifting wheel-track mechanisms that transition from a round wheel to a triangular track and back again while the vehicle is on the move, for instant improvements to tactical mobility and maneuverability on diverse terrains.

Electric In-hub Motor

Putting motors directly inside the wheels offers numerous potential benefits for combat vehicles, such as heightened acceleration and maneuverability with optimal torque, traction, power, and speed over rough or smooth terrain. In an earlier demonstration, QinetiQ demonstrated a unique approach, incorporating three gear stages and a complex thermal management design into a system small enough to fit a standard military 20-inch/51-cm rim.

Multi-mode Extreme Travel Suspension (METS)

Pratt & Miller’s METS system aims to enable high-speed travel over rough terrain while keeping the vehicle upright and minimizing occupant discomfort. The vehicle demonstrator incorporates standard military 20-inch/51-cm wheels, advanced short-travel suspension of four-to-six inches, and a novel high-travel suspension that extends up to six feet – 42 inches/106.7 cm upward and 30 inches/76.2 cm downward. The demonstration in May showed off its ability to tackle steep slopes and grades by actively and independently adjusting the hydraulic suspension on each wheel of the vehicle.

 

Crew Augmentation

Traditional combat vehicle designs have small windows that improve protection, but limit visibility. GXV-T sought solutions with multiple onboard sensors and technologies to provide high-resolution, 360-degree situational awareness while keeping the vehicle enclosed.

Enhanced 360-degree Awareness with Virtual Windows

Honeywell International demonstrated its windowless cockpit in an All-Terrain Vehicle (ATV) with an opaque canopy. The 3-D near-to-eye goggles, optical head-tracker and wrap-around Active Window Display screens provide real-time, high-resolution views outside the vehicle. In off-road courses, drivers have completed numerous tests using the system in roughly the same time as drivers in All Terrain Vehicles with full visibility.

Virtual Perspectives Augmenting Natural Experience (V-PANE)

A tactical vehicle offers limited visibility and data for decision-making, especially when moving rapidly through unfamiliar territory. Raytheon BBN Technologies’ V-PANE technology demonstrator fuses data from multiple vehicle-mounted video and LiDAR cameras to create a real-time 3-D model of the vehicle and its nearby surroundings. In a final Phase 2 demonstration, drivers and commanders in a windowless recreational vehicle successfully switched among multiple virtual perspectives to accurately maneuver the vehicle and detect targets of interest during both low- and high-speed travel.

Off-Road Crew Augmentation (ORCA)

A second CMU NREC technology demonstration, ORCA aims to predict in real time the safest and fastest route and when necessary, enable a vehicle to drive itself off-road – even around obstacles. In Phase 2 testing, drivers using the ORCA aids and visual overlays traveled faster between waypoints and eliminated nearly all pauses to determine their routes. The team found autonomy improved either vehicle speed or risk posture, and sometimes both.

 

Walker said GXV-T performers are pursuing a variety of transition paths for the new technologies.

«DARPA’s excited about the progress made to date on the GXV-T program and we look forward to working with the Services to transition these technologies into ground vehicle technologies of the future», said Walker.

DARPA’s Ground X-Vehicle Technologies (GXV-T) program demonstrations show progress on technologies for traveling quickly over varied terrain and improving situational awareness and ease of operation

Drone swarms

Under DARPA’s Offensive Swarm-Enabled Tactics (OFFSET) program, Raytheon BBN Technologies is developing technology to direct and control swarms of small, autonomous air and ground vehicles. The technology includes:

  • a visual interface that allows «drag and drop» creation and manipulation of drone tactics;
  • a game-based simulator to evaluate those tactics;
  • a physical swarm testbed to perform live tactics evaluations.
The Coyote UAS is a low-cost, expendable system with a broad spectrum of capabilities
The Coyote UAS is a low-cost, expendable system with a broad spectrum of capabilities

«Operators use speech or gestures to control the swarm. This is a tremendous advantage during operations», said Shane Clark, Doctor of Philosophy (Ph.D.) and principal investigator on the program. «The system provides sensor feeds and mission status indicators for complete situational awareness».

The flexible, scalable programming software and simulation environment means users can coordinate drone behaviors in teams composed of different vehicle types that use various sensors.

Defense Advanced Research Projects Agency (DARPA) is inviting additional organizations to participate in OFFSET as «sprinters» through an open Broad Agency Announcement. Sprinters can create their own novel swarm tactics and the Raytheon BBN team will work with them to evaluate the tactics in simulation, and possibly field them for live trials.

In 2016, Raytheon, as part of the Office of Naval Research Low-Cost UAV Swarming Technology (LOCUST) program, conducted demonstrations that successfully netted together 30 Coyote Unmanned Aerial Vehicles (UAVs) in a swarm. Raytheon BBN Technologies is a wholly owned subsidiary of Raytheon Company.

Phase 1 Swarm

The Defense Advanced Research Projects Agency (DARPA) selected Northrop Grumman Corporation as a Phase 1 Swarm Systems Integrator for the Agency’s OFFensive Swarm-Enabled Tactics (OFFSET) program. As part of the program, Northrop Grumman will launch its first open architecture test bed and is seeking participants to create and test their own swarm-based tactics on the platform. Northrop Grumman is teamed with Intelligent Automation, Inc. (IAI) and the Interactive Computing Experiences Research Cluster, directed by Doctor Joseph LaViola at the University of Central Florida.

Northrop Grumman Launches First Open Architecture Test Bed to Support DARPAs OFFensive Swarm-Enabled Tactics OFFSET Program
Northrop Grumman Launches First Open Architecture Test Bed to Support DARPAs OFFensive Swarm-Enabled Tactics OFFSET Program

As part of the DARPA OFFSET program, Northrop Grumman serves as a swarm systems integrator, tasked with designing, developing and deploying a swarm-system, open-based architecture for swarm technologies in both a game-based environment and physical test bed. The team has been tasked to produce tactics and technologies to test on the architecture and is responsible for engaging a wider development and user audience through rapid technology-development exercises known as «swarm sprints».

Approximately every six months, DARPA plans to solicit proposals from potential “sprinters” in one of five thrust areas: swarm tactics, swarm autonomy, human-swarm teaming, virtual environment and physical test bed. Participants from academia, small business and large corporations are invited to join in these swarm sprints. Sprinters will work with the integration team to create and test their own novel swarm tactics within the test bed environment. The end of each sprint will coincide with live physical test experiments with DARPA, the systems integrator team and other sprinters.

The goal of the OFFSET program is to provide small-unit infantry forces with small Unmanned Aircraft Systems (UASs) or small Unmanned Ground Systems (UGSs) in swarms of 250 or more robots that support diverse missions in complex urban environments. OFFSET seeks to advance the integration of modern swarm tactics and leverage emerging technologies in swarm autonomy and human-swarm teaming.

«Cognitive autonomy has the potential to transform all defense and security systems. OFFSET will explore a variety of applications in relevant mission scenarios», said Vern Boyle, vice president, advanced technologies, Northrop Grumman Mission Systems. «We are applying cutting-edge technologies in robotics, robot autonomy, machine learning and swarm control to ultimately enhance our contributions to the warfighter».

MOCCA program

The U.S. Defense Advanced Research Projects Agency (DARPA) has awarded BAE Systems a $4.6 million contract for its Mobile Offboard Clandestine Communications and Approach (MOCCA) program. The MOCCA program’s goal is to enable submarines to detect other submerged vessels at greater distances, while minimizing the risk of counter-detection.

The company is working with DARPA to enable submarines to detect other submerged vessels at greater distances, while minimizing the risk of counter-detection
The company is working with DARPA to enable submarines to detect other submerged vessels at greater distances, while minimizing the risk of counter-detection

«Advances in maritime technology are critical to the Department of Defense and an area where the U.S. military can continue to strengthen its advantage», said Geoff Edelson, director of Maritime Systems and Technology at BAE Systems. «With the resurgence of near-peer competitors and an increasing number of submarines, MOCCA technology will provide Navy submariners with a vital asymmetrical advantage against a rapidly proliferating undersea threat».

To meet the MOCCA program’s ambitious Phase 1 goals, BAE Systems’ researchers will design efficient sonar capabilities to maximize detection range and improve target identification and tracking.

The MOCCA program demonstrates BAE Systems’ strength in innovation and its capability to design technologies for future combat scenarios. The research and development team at BAE Systems regularly works closely with DARPA and other defense research institutes to create and deliver capabilities that improve the competitive advantages of the U.S. armed forces.

Experimental Spaceplane

DARPA has selected The Boeing Company to complete advanced design work for the Agency’s Experimental Spaceplane (XS-1) program, which aims to build and fly the first of an entirely new class of hypersonic aircraft that would bolster national security by providing short-notice, low-cost access to space. The program aims to achieve a capability well out of reach today – launches to low Earth orbit in days, as compared to the months or years of preparation currently needed to get a single satellite on orbit. Success will depend upon significant advances in both technical capabilities and ground operations, but would revolutionize the Nation’s ability to recover from a catastrophic loss of military or commercial satellites, upon which the Nation today is critically dependent.

Phantom Express is envisioned as a highly autonomous experimental spaceplane, shown preparing to launch its expendable second stage on the top of the vehicle in this artist’s concept. The Defense Advanced Research Projects Agency is collaborating with Boeing to fund development of the Experimental Spaceplane (XS-1) program (Boeing rendering)
Phantom Express is envisioned as a highly autonomous experimental spaceplane, shown preparing to launch its expendable second stage on the top of the vehicle in this artist’s concept. The Defense Advanced Research Projects Agency is collaborating with Boeing to fund development of the Experimental Spaceplane (XS-1) program (Boeing rendering)

«The XS-1 would be neither a traditional airplane nor a conventional launch vehicle but rather a combination of the two, with the goal of lowering launch costs by a factor of ten and replacing today’s frustratingly long wait time with launch on demand», said Jess Sponable, DARPA program manager. «We’re very pleased with Boeing’s progress on the XS-1 through Phase 1 of the program and look forward to continuing our close collaboration in this newly funded progression to Phases 2 and 3 – fabrication and flight».

The XS-1 program envisions a fully reusable unmanned vehicle, roughly the size of a business jet, which would take off vertically like a rocket and fly to hypersonic speeds. The vehicle would be launched with no external boosters, powered solely by self-contained cryogenic propellants. Upon reaching a high suborbital altitude, the booster would release an expendable upper stage able to deploy a 3,000-pound/1,360-kg satellite to polar orbit. The reusable first stage would then bank and return to Earth, landing horizontally like an aircraft, and be prepared for the next flight, potentially within hours.

In its pursuit of aircraft-like operability, reliability, and cost-efficiency, DARPA and Boeing are planning to conduct a flight test demonstration of XS-1 technology, flying 10 times in 10 days, with an additional final flight carrying the upper-stage payload delivery system. If successful, the program could help enable a commercial service in the future that could operate with recurring costs of as little as $5 million or less per launch, including the cost of an expendable upper stage, assuming a recurring flight rate of at least ten flights per year – a small fraction of the cost of launch systems the U.S. military currently uses for similarly sized payloads. (Note that goal is for actual cost, not commercial price, which would be determined in part by market forces.)

To achieve these goals, XS-1 designers plan to take advantage of technologies and support systems that have enhanced the reliability and fast turnaround of military aircraft. For example, easily accessible subsystem components configured as line replaceable units would be used wherever practical to enable quick maintenance and repairs.

The XS-1 Phase 2/3 design also intends to increase efficiencies by integrating numerous state-of-the-art technologies, including some previously developed by DARPA, NASA, and the U.S. Air Force. For example, the XS-1 technology demonstrator’s propulsion system is an Aerojet Rocketdyne AR-22 engine, a version of the legacy Space Shuttle main engine (SSME).

Once Phantom Express reaches the edge of space, it would deploy the second stage and return to Earth. It would then land on a runway to be prepared for its next flight by applying operation and maintenance principles similar to modern aircraft (Boeing rendering)
Once Phantom Express reaches the edge of space, it would deploy the second stage and return to Earth. It would then land on a runway to be prepared for its next flight by applying operation and maintenance principles similar to modern aircraft (Boeing rendering)

Other technologies in the XS-1 design include:

  • Advanced, lightweight composite cryogenic propellant tanks to hold liquid oxygen and liquid hydrogen propellants;
  • Hybrid composite-metallic wings and control surfaces able to withstand the physical stresses of suborbital hypersonic flight and temperatures of more than 2,000º F/1,093º C;
  • Automated flight-termination and other technologies for autonomous flight and operations, including some developed by DARPA’s Airborne Launch Assist Space Access (ALASA) program.

XS-1 Phase 2 includes design, construction, and testing of the technology demonstration vehicle through 2019. It calls for initially firing the vehicle’s engine on the ground 10 times in 10 days to demonstrate propulsion readiness for flight tests.

Phase 3 objectives include 12 to 15 flight tests, currently scheduled for 2020. After multiple shakedown flights to reduce risk, the XS-1 would aim to fly 10 times over 10 consecutive days, at first without payloads and at speeds as fast as Mach 5/3,836 mph/6,174 km/h. Subsequent flights are planned to fly as fast as Mach 10, and deliver a demonstration payload between 900 pounds/408 kg and 3,000 pounds/1,360 kg into low Earth orbit.

Another goal of the program is to encourage the broader commercial launch sector to adopt useful XS-1 approaches, processes, and technologies that facilitate launch on demand and rapid turnaround – important military and commercial needs for the 21st century. Toward that goal, DARPA intends to release selected data from its Phase 2/3 tests and will provide to all interested commercial entities the relevant specs for potential payloads.

«We’re delighted to see this truly futuristic capability coming closer to reality», said Brad Tousley, director of DARPA’s Tactical Technology Office (TTO), which oversees XS-1. «Demonstration of aircraft-like, on-demand, and routine access to space is important for meeting critical Defense Department needs and could help open the door to a range of next-generation commercial opportunities».

Experimental Spaceplane (XS-1) Phase 2/3 Concept Video

VTOL X-Plane

DARPA has completed flight-testing of a sub-scale version of a novel aircraft design as part of its Vertical TakeOff and Landing (VTOL) X-Plane program, and is proceeding with work to develop a full-scale version of the groundbreaking plane. Developed and fabricated by Aurora Flight Sciences, the revolutionary aircraft includes 24 electric ducted fans – 18 distributed within the main wings and six in the canard surfaces, with the wings and canards tilting upwards for vertical flight and rotating to a horizontal position for wing-borne flight. The successful tests suggest there is a time in the not-so-distant future when VTOL aircraft could fly much faster and farther than any existing hover-capable craft, and take off and land almost anywhere.

VTOL X-plane hovering in place before transitioning to horizontal flight
VTOL X-plane hovering in place before transitioning to horizontal flight

Subscale testing began on the VTOL program in March of 2016 and the first phase of testing ended after six flights with demonstration of auto take off, sustained hover, directional and translational control (including lateral and rearward flight), waypoint navigation, and auto landing. Later, the aircraft wing and canard tilt mechanisms, tilt schedules, and wing-borne flight controls were enabled for testing. Four of the test flights featured an expanded flight envelope in which the vehicle experimented with increases in air speed until the wing generated most of the lift.

«The VTOL demonstrator was designed specifically to test the aerodynamic design of the aircraft, validate flight dynamics, and develop the flight and mission-systems controls for application to the full-scale vehicle», said Ashish Bagai, DARPA program manager. «The aircraft exhibited exceptional flight characteristics, with no loss in altitude even as it transitioned from vertical to horizontal flight. It also demonstrated aerodynamic effectiveness of the distributed propulsive system».

The subscale aircraft flight and mission control architectures will, for the most part, be carried over into the full-scale VTOL aircraft, but with a few additions and improvements. According to Bagai, the full-scale aircraft will incorporate a triple-redundant flight control system instead of a single system. A hybrid turboshaft engine driving electric generators to power the fan units, versus the demonstrator’s batteries, will power the full-scale aircraft. Finally, the full-scale aircraft fan units will be synchronized to the generators and turn at a constant RPM, but incorporate variable pitch, whereas the demonstrator’s fans are speed controlled.

Composite image of VTOL subscale test aircraft in horizontal flight
Composite image of VTOL subscale test aircraft in horizontal flight

In addition to serving as a flight controls systems developmental aircraft, the VTOL subscale demonstrator advanced a number of technologies such as 3D-printed plastics for flight structures and aerodynamic surfaces as well as embedded distributed electric propulsion. The subscale demonstrator also improved methods to develop the aerodynamic databases upon which the air-vehicle control system is modeled, and provided lessons for the flight control system.

With the subscale test flights completed, the aircraft will be preserved for possible additional tests in the future. Meanwhile, all ongoing-program efforts will focus on the development of the full-scale VTOL X-Plane aircraft, which now bears the official designation of XV-24A.

The XV-24A will weigh 12,000 pounds/5,443 kg compared to the demonstrator’s 322 pounds/146 kg, and will aim to demonstrate specific performance objectives stipulated by DARPA: flight speeds in excess of 300 knots/345 mph/555.6 km/h, full hover and vertical flight capabilities, and – relative to helicopters – a 25 percent improvement in hovering efficiency and 50 percent reduction in system drag losses during cruise.

«These are ambitious performance parameters», Bagai said, «which we believe will push current technologies to the max and enable a new generation of vertical flight operational capabilities».

DARPA Completes Testing of Subscale Hybrid Electric VTOL X-Plane

 

Aircraft carriers
in the sky

DARPA recently completed Phase 1 of its Gremlins program, which envisions volleys of low-cost, reusable Unmanned Aerial Systems (UASs) – or «gremlins» – that could be launched and later retrieved in mid-air. Taking the program to its next stage, the Agency has now awarded Phase 2 contracts to two teams, one led by Dynetics, Inc. (Huntsville, Alabama) and the other by General Atomics Aeronautical Systems, Inc. (San Diego, California).

DARPA’s Gremlins program seeks to develop innovative technologies and systems that would enable existing aircraft to launch volleys of low-cost, reusable unmanned aerial systems (UASs) and safely and reliably retrieve them in mid-air. In an important step toward that goal, DARPA has awarded Phase 2 contracts for Gremlins to teams led by Dynetics, Inc., and General Atomics Aeronautical Systems, Inc.
DARPA’s Gremlins program seeks to develop innovative technologies and systems that would enable existing aircraft to launch volleys of low-cost, reusable unmanned aerial systems (UASs) and safely and reliably retrieve them in mid-air. In an important step toward that goal, DARPA has awarded Phase 2 contracts for Gremlins to teams led by Dynetics, Inc., and General Atomics Aeronautical Systems, Inc.

«The Phase 1 program showed the feasibility of airborne UAS launch and recovery systems that would require minimal modification to the host aircraft», said Scott Wierzbanowski, DARPA program manager. «We’re aiming in Phase 2 to mature two system concepts to enable ‘aircraft carriers in the sky’ using air-recoverable UASs that could carry various payloads – advances that would greatly extend the range, flexibility, and affordability of UAS operations for the U.S. military».

Gremlins Phase 2 research seeks to complete preliminary designs for full-scale technology demonstration systems, as well as develop and perform risk-reduction tests of individual system components. Phase 3 goals include developing one full-scale technology demonstration system and conducting flight demonstrations involving airborne launch and recovery of multiple gremlins. Flight tests are currently scheduled for the 2019 timeframe.

Named for the imaginary, mischievous imps that became the good luck charms of many British pilots during World War II, the program envisions launching groups of UASs from multiple types of military aircraft – including bombers, transport, fighters, and small, unmanned fixed-wing platforms – while out of range of adversary defenses. When the gremlins complete their mission, Lockheed C-130 Hercules transport aircraft would retrieve them in the air and carry them home, where ground crews would prepare them for their next use within 24 hours.

The gremlins’ expected lifetime of about 20 uses could provide significant cost advantages over expendable unmanned systems by reducing payload and airframe costs and by having lower mission and maintenance costs than conventional manned platforms.

Collaborative Operations in Denied Environment (CODE) Phase 2 Concept Video

Undersea Network

DARPA’s Tactical Undersea Network Architecture (TUNA) program recently completed its initial phase, successfully developing concepts and technologies aimed at restoring connectivity for U.S. forces when traditional tactical networks are knocked offline or otherwise unavailable. The program now enters the next phase, which calls for the demonstration of a prototype of the system at sea.

Artist’s concept showing the TUNA architecture with an undersea fiber-optic backbone enabling a temporary communications network when traditional tactical data links are unavailable
Artist’s concept showing the TUNA architecture with an undersea fiber-optic backbone enabling a temporary communications network when traditional tactical data links are unavailable

TUNA seeks to develop and demonstrate novel, optical-fiber-based technology options and designs to temporarily restore radio frequency (RF) tactical data networks in a contested environment via an undersea optical fiber backbone. The concept involves deploying RF network node buoys – dropped from aircraft or ships, for example – that would be connected via thin underwater fiber-optic cables. The very-small-diameter fiber-optic cables being developed are designed to last 30 days in the rough ocean environment – long enough to provide essential connectivity until primary methods of communications are restored.

«Phase 1 of the program included successful modeling, simulation, and at-sea tests of unique fiber-cable and buoy-component technologies needed to make such an undersea architecture work», said John Kamp, program manager in DARPA’s Strategic Technology Office. «Teams were able to design strong, hair-thin, buoyant fiber-optic cables able to withstand the pressure, saltwater, and currents of the ocean, as well as develop novel power generation concepts».

Supplying power to floating buoy nodes on the open sea presents a particular challenge. During the first phase of the program, the University of Washington’s Applied Physics Lab (APL) developed a unique concept called the Wave Energy Buoy that Self-deploys (WEBS), which generates electricity from wave movement. The WEBS system is designed to fit into a cylinder that could be deployed from a ship or aircraft.

Having now entered its second and final phase, the program is advancing to design and implement an integrated end-to-end system, and to test and evaluate this system in laboratory and at-sea demonstrations. As a test case for the TUNA concept, teams are using Link 16—a common tactical data network used by U.S. and allied forces’ aircraft, ships, and ground vehicles.

DARPA wraps up first phase of program developing temporary underwater fiber-optics communications networks to ensure connectivity when tactical networks are unavailable

Underwater Radio

The Mechanically Based Antenna program could enable radio communication through seawater and the ground and directly between warfighters hundreds and ultimately thousands of kilometers apart.

A fundamentally new approach to building radio transmitters could open previously impossible communication channels for warfighters
A fundamentally new approach to building radio transmitters could open previously impossible communication channels for warfighters

Here’s something easy to forget when you are chatting on your cell phone or flipping channels on your smart TV: although wireless communication seems nothing short of magic, it is a brilliant, reality-anchored application of physics and engineering in which radio signals travel from a transmitter to a receiver in the form of electric and magnetic fields woven into fast-as-light electromagnetic waves. That very same physics imposes some strict limits, including ones that frustrate the Department of Defense (DoD). Key among these is that radio frequency signals hit veritable and literal walls when they encounter materials like water, soil, and stone, which can block or otherwise ruin those radio signals. This is why scuba buddies rely on sign language and there are radio-dead zones inside tunnels and caves.

With his newly announced A MEchanically Based Antenna (AMEBA) effort, program manager Troy Olsson of DARPA’s Microsystems Technology Office is betting on a little-exploited aspect of electromagnetic physics that could expand wireless communication and data transfer into undersea, underground, and other settings where such capabilities essentially have been absent. The basis for these potential new abilities are ultra-low-frequency (ULF) electromagnetic waves, ones between hundreds of hertz and 3 kilohertz (KHz), which can penetrate some distance into media like water, soil, rock, metal, and building materials. A nearby band of very-low-frequency (VLF) signals (3 KHz to 30 KHz) opens additional communications possibilities because for these wavelengths the atmospheric corridor between the Earth’s surface and the ionosphere – the highest and electric-charge-rich portion of the upper atmosphere – behaves like a radio waveguide in which the signals can propagate halfway around the planet.

«If we are successful, scuba divers would be able to use a ULF channel for low bit-rate communications, like text messages, to communicate with each other or with nearby submarines, ships, relay buoys, Unmanned Aerial Vehicles (UAVs), and ground-based assets, Through-ground communication with people in deep bunkers, mines, or caves could also become possible», Olsson said. And because of that atmospheric waveguide effect, VLF systems might ultimately enable direct soldier-to-soldier text and voice communication across continents and oceans.

To date, there’s been a huge and expensive rub to actually pulling off low-frequency radio communication in the versatile ways that Olsson has in mind. The wavelengths of VLF and ULF radio signals rival the distances across cities and states, respectively. And since longer wavelengths have required taller antennas, communications in these frequency bands have entailed the construction of enormous and costly transmitter structures. A VLF antenna that the U.S. Navy built on a remote peninsula in Cutler, Maine, in the heat of the Cold War just to send a trickle of data to submarines makes the point: the gargantuan transmitter complex occupies 2,000 acres/8 square kilometers, features 26 towers up to 1,000 feet/305 m high, and operates with megawatt levels of power.

With the AMEBA program, Olsson aims to develop entirely new types of VLF and ULF transmitters that are sufficiently small, light, and power efficient to be carried by individual warfighters, whether they are on land, in the water, or underground. Rather than relying on electronic circuits and power amplifiers to create oscillating electric currents that, when driven into antennas, initiate radio signals, the new low-frequency VLF and ULF antennas sought in the AMEBA program would generate the signals by mechanically moving materials harboring strong electric or magnetic fields.

In principle, this is as simple as taking a bar magnet or an electret – an insulating substance, such as a cylinder of quartz (silica) glass, in which positive and negative electric charges are permanently segregated to create an electric dipole – and moving it at rates that will generate ULF and VLF frequencies. To open up practical new capabilities in national security contexts, however, the challenges include packing more powerful magnetic and electric fields into smaller volumes with smaller power requirements than has ever been achieved before for a ULF or VLF transmitter. That will require innovations in chemistry and materials (new magnets and electrets), design (shapes and packing geometries of these materials), and mechanical engineering (means of mechanically moving the magnets and electrets to generate the RF signals).

«Mobile low-frequency communication has been such a hard-technological problem, especially for long-distance linkages, that we have seen little progress in many years», said Olsson. «With AMEBA, we expect to change that. And if we do catalyze the innovations we have in mind, we should be able to give our warfighters extremely valuable mission-expanding channels of communications that no one has had before».