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Laser Power Beaming to Sustain Small UAVs


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Directed Energy, Microelectronics, Integrated Network System of Systems The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Research and develop an innovative power beaming and receiver system to a small Unmanned Aircraft System (sUAS). Deliver a prototype demonstrating power beaming (PB) in a relevant outdoors environment. DESCRIPTION: Unmanned vehicles are playing increasingly central and sophisticated roles on the battlefield and fulfill many different missions during both peace and wartime. Small autonomous vehicles like Group 1 sUAS represent a top DoD and Army priority, and are common in military formations, with wide distribution to units across the Services and in civilian agencies. These sUAS play a critical role in communication, situational awareness, etc. for squads and individual Warfighters, yet their battery lifetimes are limited to the 30-minute range [1,2], which curtails their mission effectiveness; it is unrealistic and cognitively burdensome to swap out batteries by hand every half-hour in a contested battlespace. New laser and microwave directed energy technologies, including new receiver materials technology, enable “remote power”, where energy is transmitted to a vehicle’s receiver, using an intense, directed-energy beam [3-6]. The vehicle will be more mobile and lethal, not burdened by a heavy load of batteries and frequent battery swaps, and the unsustainable and vulnerable logistics load of extra batteries will be reduced or eliminated. Calculations, based on representative sUAS and onboard batteries, indicate that if 100 W could be continuously supplied to the sUAS batteries in-flight (implying > 100 W incident power on the sUAS receiver and even higher powers in the transmitted beam at the source), the mission lifetime of the sUAS could double to one hour, before the battery would need to be changed. If 200 W could be delivered onboard the sUAS to the battery, the sUAS could operate indefinitely, and the need for extra batteries greatly curtailed. Early demonstrations focused on a UAS relatively stationary in a wind tunnel [7]; a more applicable demonstration is needed. Beaming power to a sUAS is technically challenging: a powerful beam must be continuously aimed at and confined within the sUAS-borne receiver for a long time, despite atmospheric turbulence and sUAS motion. Eye safety and the effect of the receiver on sUAS motion must also be considered. Photovoltaic receivers have been proven to be lightweight and efficient, especially for space and portable power applications. Photovoltaic cells for PB must also maximize power output and handle some amount of movement (due to atmospheric turbulence, sUAS motion, etc.) of the incident beam, and they must be thermally stable, not heating and losing efficiency excessively under continuous illumination by a powerful beam whose centroid wanders. Rectennas or bolometers are also possible receivers, especially for wavelengths in the short-wave infrared regime or longer. In all cases, new materials, robust to temperature swings and capable of delivering power, must be designed or reconfigured. The goal of this Topic is to research and develop a novel PB system to extend the range of Group 1 sUAS (< 20 lb.) far beyond the current limitation of approximately one-half hour flying time for Group 1 sUAS, at least doubling it, while not negatively impacting mission (due to attached receiver) or generating significant safety issues (demonstrated outdoors in Phase II). Laser PB may be best for small Group 1 sUAS. PHASE I: NOTE THAT IN-HOUSE CONTRACTORS (ORISE POSTDOCTORAL ASSOCIATES) WILL ASSIST WITH PROPOSAL REVIEW Identifying, through early-stage experiments and modeling (not just modeling), a PB system that will provide at least 100 W continuous onboard a sUAS which is carrying out a simple mission (e.g., reconnaissance, or observing a fixed area), at a range of 500 m or more from the source. The PB system must have source, receiver, and sUAS technology with technical merit specified. The wavelength of the PB source and the receiver can be selected by the responding firm, as can the outdoors environment and mission scenario, but the sUAS must be “blue”; e.g., on the US government’s permitted acquisition list. Model, and conduct initial experiments informing understanding of, power beaming to a sUAS. In reports, comment on eye safety, range, aiming stability, sUAS type, mission and scaling to faster re-charge times. Predict and justify a technical and programmatic path, based on modeling and initial experiments (not just modeling), of extending mission lifetime, ideally by 30 minutes with less than 60 minutes of charging and range of at least 500 meters. Employ preliminary experimental data, for example using a relevant laser in a laboratory. PHASE II: NOTE THAT IN-HOUSE CONTRACTORS (ORISE POSTDOCTORAL ASSOCIATES) WILL ASSIST WITH PROPOSAL REVIEW Building on Phase I work, in Year 1 of Phase II: demonstrate a prototype, consisting of a full PB system and Group 1 sUAS with receiver, and demonstrate in a lab environment the power delivery to the sUAS batteries in an eyesafe manner. Also in Year 1, demonstrate receiver robustness under high power densities and interaction with a moving beam. In Year 2, demonstrate the full PB system outdoors in the relevant environment with the sUAS’ executing a simple mission, like reconnaissance (moving in a straight line) or hovering or circling a protected area. Power levels should be at least 100 W onboard (not incident on) a sUAS, and the power must be demonstrated over a distance of at least 500 meters continuously. At the end of Phase II, demonstrate onboard delivery of 100 W to the sUAS battery over a range of at least 500 meters outdoors. PHASE III DUAL USE APPLICATIONS: "Scale the technology demonstrated in Phase II up to a level that produces a full system that could be used for a sUAS mission, such as reconnaissance/situational awareness, in an operationally relevant environment for the Army, including probably larger range to 1 km and beyond. The technology must be of interest for the Warfighter and civilian (e.g., first responders) in challenging environments; for example, for reporting back to Warfighters and/or civilian emergency personnel situations in dangerous environments (battlefield, contaminated area, mines, etc.). Scale up the technology from Group 1 sUAS to much larger UAS that can travel across continents, especially where solar power cannot be relied on. Dual use potential comes from (1) the great commercial potential of sUAS and UAS in general to deliver commercial products in an efficient and targeted way (2) the application of sUAS and autonomous assets in general to penetrate dangerous environments unfit for humans for reconnaissance and retrieval purposes, especially where remote power is advantageous because it would be dangerous and inefficient to change sUAS batteries by hand (e.g., environments contaminated by toxic chemicals or pollutants) and (3) the similarity of power beaming to other directed energy applications where the sUAS is flying in an unauthorized area (e.g., near an airport), and where law enforcement or military needs additional tools to defend the area. It is envisioned that this technology will benefit from large emerging civilian markets where remote power is increasingly sought as UAS travel further and are required to carry larger payloads." REFERENCES: 1. Article/info sheet titeld "Skydio X2D uses unmatched AI to turn every operator into an expert pilot" 2. National Academies of Sciences, Engineering, and Medicine. 2018. CounterUnmanned Aircraft System [CUAS) Capability for Battalion-and-Below Operations: Abbreviated Version of a Restricted Report. Washington, DC: The National Academies Press. 3. Naval Research Laboratory Press Release (2019): “Researchers transmit energy with laser in historic power-beaming demonstration” 4. IEEE Spectrum News Article (2021): “New Optical Antennas Harvest 100 Times More Electricity from Heat” 5. Science v. 367 p. 1341 (2020; abstract only): “Electrical power generation from moderate-temperature radiative thermal sources” 6. Naval Research Laboratory Press Release (2022): “NRL Conducts Successful Terrestrial Microwave Power Beaming Demonstration” 7. Lockheed Martin News release; PR Newswire; Palmdale Calif.; July 11, 2012; KEYWORDS: Power beaming, Remote power, Unmanned Aerial Vehicles, Autonomy, Photovoltaic, Receiver, Near-Infrared, Short-wave infrared
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