Wi²SAR | Drone-based Wilderness Search and Rescue

A Growing Crisis

Wilderness Search & Rescue Demands Are Escalating

0%

Annual Growth

Average increase in WiSAR incidents since 2016 [1]

0%

High Casualties Rate

Victims suffer injuries in wilderness emergencies [1]

Challenge

Visual Line-of-sight Obstruction

Tree canopy creates visual obstruction, even infrared is difficult to penetrate for identification [2]

Opportunity

Wi-Fi for Discovery & Identification

Find lost person through Wi-Fi device; identify via auto-connection

Wi²SAR Prototype

Key Techniques

Victim Discovery

Wi²SAR leverages the automatic reconnection behavior of modern Wi-Fi devices. By simulating a known network (e.g., home Wi-Fi), the drone elicits identifiable packets from the victim's device. This mechanism enables rapid discovery and identification of the target victim without requiring any prior app installation or active user cooperation.

Direction Finding

A custom 3D-printed Luneburg Lens is integrated to amplify directional signal strength differences. This passive optical device enables a novel RSS-only, long-range 3D Angle-of-Arrival (AoA) estimation method. It significantly extends the operational range and eliminates the need for complex phase calibration on moving drones.

Autonomous Navigation

The system employs an adaptive drone navigation scheme that guides the drone toward the target efficiently. It uses a dual-phase search strategy: an initial exploratory grid search to detect the signal, followed by a direction-guided approach that continuously refines the heading based on real-time AoA estimates to pinpoint the victim's location.