Whispers in the snow: harnessing LoRa technology for search and rescue operations

Venturing into the heart of avalanche search and rescue (SaR), our mission was clear: to study the potential of LoRa technology in localizing targets buried under an avalanche. With line-of-sight out of the equation, and environmental elements like temperature and humidity against us, we embarked on a challenging data collection campaign. Our setup consists of one transmitter and four receivers positioned on an open plateau located in Col de Mez, Dolomites, at 1850 m. Receivers have been strategically placed to cover a square region of 100m, replicating a typical avalanche field. Data have been collected considering two key factors: 1) the depth of the target and 2) the type of snow. Specifically, we collected data in winter with dry and cold snow conditions, as well as during the spring period characterized by wet snow, which degrades signal propagation. Through the frosty air, we collected and analyzed the Received Signal Strength (RSS) and Signal-to-Noise Ratio (SNR) parameters, unveiling the secrets of LoRa propagation under challenging conditions. But our journey didn't end there. We further investigated LoRa performance, determining the boundaries of distance to see just how far LoRa's whispers could travel from their snowy grave. And what we discovered was nothing short of groundbreaking: LoRa's potential to shine bright even in the harshest environments, up to 400m from the target point. Lastly, our dataset comprises measurements collected with a professional drone equipped with an omni-directional antenna, covering a square field of 100m side with 121 measurement points. The data we collected enables two possible lines of investigation. On one hand, we aim to characterize LoRa propagation under snow conditions, while on the other hand, we are interested in evaluating the possibility of adopting LoRa to localize a target using localization and proximity detection algorithms.