Novel Radio Frequency Sensing Technologies | SBIR

OUSD (R&E) critical technology area(s): Integrated Sensing and Cyber

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 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: Develop, integrate, and flight-test a high-altitude (~40,000 ft), high-speed (~400 knots) airborne geologic sensing system. The system must be capable of providing rapid, stand-off 3D subsurface tomographic imaging to detect subterranean features such as metals and critical minerals.

Description: Detecting and mapping deep subsurface mineral deposits typically requires localized or low-altitude operations. Current state-of-the-art airborne subsurface radar systems are limited to relatively low-altitude and low-speed platforms due to the physical limitations of signal attenuation over distance. Increasing altitude and airspeed would allow for larger areas to be scanned in less time.

This topic seeks the rapid development of an advanced airborne system designed for the seamless integration onto high-altitude fixed-wing aircraft. Proposers must address the physical scaling laws of radar propagation through lossy media. According to the radar equations for small targets of a radar cross section of approximately one wavelength, the necessary transmit power scales as a function of range to the fourth power (R4). For instance, transitioning from a 10,000 ft baseline to a 40,000 ft operational altitude represents a 4x increase in distance, nominally demanding a 256x increase in radiated power to maintain equivalent subsurface imaging performance.

Due to the higher power requirements at higher altitudes, system designs must prioritize transmit power scaling, advanced antenna structure designs, and robust heat dissipation systems.

To facilitate rapid, modular deployment across diverse airframes without requiring permanent, costly aircraft modifications, the entire system must be designed as a fully self-contained payload. It must utilize independent, internal power generation and an edge computational architecture.

Key technical challenges that proposers must address include:

1. High-Power Transmitter & Power Scaling: Engineering and validating a highly reliable kW-class RF power amplifier.
2. Aerodynamic & Structural Antenna Design: Designing and reinforcing an externally deployable or structurally integrated antenna system capable of withstanding aerodynamic loads at relevant velocities (~400 knots) and altitudes (~40,000 ft).
3. Thermal Dissipation & Management: Integrating passive or active high-capacity heat dissipation systems to mitigate thermal loads under sustained high-power transmit cycles.
4. RF Shielding & Electromagnetic Compatibility (EMC): Implementing advanced RF shielding and electrical isolation to guarantee zero electromagnetic interference with the host aircraft’s flight navigation, control, and mission avionics.
5. Field-Programmable Gate Arrays (FPGAs) & Edge Processing: Selecting FPGAs and processing techniques that can handle increased signal propagation delays, modified waveforms, and real-time tomographic data processing at high standoff distances.

Phase I

This topic is soliciting Direct to Phase II (DP2) proposals only. Proposers must submit feasibility documentation in lieu of a Phase I proposal. Proposers must demonstrate that they have already developed, integrated, and validated an airborne subsurface radar or similar system in a physical environment (e.g., low-altitude, low-speed flight regimes up to 10,000 ft). Modeling and simulation data alone is not sufficient to prove feasibility.

The submitted feasibility documentation must include:

1. Empirical Flight Data: Representative 3D tomographic subsurface reconstructions, signal-to-noise ratio (SNR) calculations, and imagery demonstrating successful detection of underground mineral deposits.
2. Receiver Characterization: Technical documentation proving the receiver operates at a low thermal noise floor.
3. Analytical Scaling Models: Detailed physical, mathematical, and electromagnetic models validating the R4 scaling equations and mapping the exact architectural transition from a low-power baseline to a high-power, high-altitude design.

Proposals should contain preliminary data (published or unpublished) supporting the rationale for the development of the candidate product(s). Describe how the product will be usable in the operational continuum or the environmental setting(s) for which it is designed.

Phase II

Phase II is an accelerated hardware realization, integration, and flight-testing campaign. Fixed Payable Milestones for this program should include:

Base Period (18 Months)

• Month 2: Subsystem Engineering – Preliminary Designs for the power amplifier, motherboard, and high-efficiency heat dissipation structures. Initial report on updated firmware architecture.
• Month 4: Subsystem Design Completion - Finalized engineering designs for all major subsystems.
• Month 6: Structural Antenna Engineering Interim Report #1 – Manufacturing progress and initial benchtop testing for the power amplifier and antenna assembly to survive aerodynamic loads of ~400 knots.
• Month 9: FPGA and Compute Development Interim Report #2 – Progress on integrated systems testing, including initial results from tomographic reconstruction algorithms at the edge.
• Month 12: Safety and Test Readiness Review (TRR) Data Package – Comprehensive safety testing results on high-voltage and high-power RF emissions and flight clearances documentation.
• Month 15: High-Altitude Flight Campaign Interim Report #3 – Preliminary data from demonstration flights on a fixed-wing platform at ~40,000 ft and speed of ~400 knots, including measurements of radiated power and signal penetration.
• Month 18: Data Analysis and Final Base Period Report – Detailed analysis of flight data, fully reconstructed 3D subsurface tomograms of test sites and system performance evaluation.

Option Period (6 Months)

• Month 21: Interim Report #4 – Detailed data analysis, algorithm enhancement, and performance improvements of the prototype system.
• Month 24: Comprehensive Final System Assessment Report – Final evaluation of performance, including 3D subsurface tomogram data of relevant structures, against a low-altitude baseline and commercial viability analysis..

Phase III dual use applications

The high-altitude geological sensing system represents a highly disruptive dual-use technology:

• Military/DoD Applications: Identifying additional domestic sources of critical minerals is a national security imperative that will improve access to materials needed for advanced defense systems. This capability would strengthen U.S. supply chain for critical minerals.
• Commercial/Civil Applications: Acts as a highly scalable "MRI for the Earth." The system could map deep-seated geologic structures to rapidly locate critical mineral reserves and rare earth element deposits buried under hundreds of meters of geology. This significantly accelerates discovery timelines, increases exploratory extraction success rates from 1-in-200 to near certainty, and optimizes geologic risk management.

References

1. DoD Joint Sensor Integration Standards, "Electromagnetic Compatibility and RF Shielding Guidelines for High-Power Airborne Payloads (MIL-STD-461G)," 2019.

Keywords

Ground Penetrating Radar, Subsurface Tomography, Standoff Radar, High-Power RF, Airborne Geophysics, Subterranean Imaging, RF Shielding, Critical Minerals.

TPOC-1-PoC

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