RFEye in the Sky

Background:

Locating wireless signals outdoors is necessary for a variety of military, law enforcement, and civil applications. Acquiring such signals is the first step, which often requires patrolling large distances over varied terrain and can be limited if terrestrial methods such as autonomous vehicles, crowdsourcing or fixed receiver arrays are used. Also, the signal acquired by terrestrial means can be severely attenuated or impaired due to Non-Line-of-Sight (NLOS), shadowing and other unknown factors. Signal acquisition using UAVs can overcome such limitations but are constrained on resources such as power, RF front-end, antenna, processing capacity, and storage.

Technology Overview:

RFEye acquires signals from uncoordinated positions within a sphere of 1-meter radius at two nearby locations. It then formulates an asynchronous, distributed receiver beamforming at the UAV to compute the Direction of Arrival (DoA) from the unknown transmitter. This includes four steps:
1.    Blind detection and extraction of unique signature in the signal to be localized.
2.    Asynchronous signal acquisition and conditioning.
3.    DoA calculation by creating a virtual distributed antenna array at UAV.
4.    Obtaining position fix of emitter using DoA from two locations.
These steps are analyzed and compared with widely used signal subspace-based DoA estimation algorithms.

Advantages:

•    Requires only one UAV equipped with a single omnidirectional antenna.
•    Achieves a median accuracy of:
        •    1.03m in 2D and 2.5m in 3D for Wi-Fi.
        •    1.15m in 2D and 2.7m in 3D for Long Range waveforms.
•    Resistant to external factors such as wind and UAV position errors.
•    Avoids the limitations of patrolling large distances using terrain-based platforms.

Applications:

•    Locating illegal or unauthorized transmitters (for example unlicensed radio stations).
•    Precisely identifying the location of targets in search and rescue operations.
•    Tracking the movement of agents in electronic warfare.

Intellectual Property Summary:

This Intellectual Property is the subject of a US Patent Application.

Stage of Development:

TRL 4 - Technology validated in lab

Licensing Status:

This technology is available for licensing.