Aerial RF Mapping: Conducting Building Signal Surveys via Drone and SDR

I Mapped an Entire Building’s RF Footprint Without Walking Inside

V Splicer demonstrated an aerial RF mapping system using a DJI Mini 2 and an RTL-SDR dongle. The setup identified two rogue access points and GPS anomalies without requiring physical building access.

Why This Matters

Traditional RF site surveys rely on manual ground traversal, which is labor-intensive and blind to aerial propagation patterns. This approach proves that perimeter security is insufficient when low-cost SDRs can triangulate internal transmitters—such as unauthorized hotspots or spoofing devices—from the air, bypassing all physical access controls.

Key Insights

• Low-cost hardware can replace expensive surveys: A $235 build (DJI Mini 2, RTL-SDR V4) achieved results comparable to $8K professional site surveys.
• RF signal penetration allows aerial mapping: 2.4 GHz Wi-Fi and cellular signals penetrate drywall and concrete, enabling signal capture from 150–200 feet altitude.
• Automated classification improves data quality: A lightweight AI model running on a Raspberry Pi 4 allows real-time tagging of Wi-Fi, Bluetooth, Zigbee, LoRa, and cellular signals.

Practical Applications

• Physical Security Audits: Using lawnmower flight patterns to identify rogue APs or ‘Evil Twin’ SSIDs that ground-level sweeps miss.
• Interference Detection: Identifying unauthorized cellular boosters that cause signal conflicts with internal communication systems.

References:

• https://dev.to/numbpill3d/i-mapped-an-entire-buildings-rf-footprint-without-walking-inside-heres-how-4hjm