"Undetected" in that context means "undetected until they're nearby". They're far from quiet. They've deployed surprisingly long-range acoustic sensor nets, fo

"Undetected" in that context means "undetected until they're nearby". They're far from quiet. They've deployed surprisingly long-range acoustic sensor nets, for tracking them by their noise: - "Zvook’s detection ranges, though much shorter than radar, are nothing to sniff at. Drones, for example, can be detected up to 5km away. For cruise missiles, the range is about 7km. To pull this off, Zvook designed curved “acoustic mirrors” half a metre in diameter. These dishes concentrate sound waves on the microphones they cup. Most listening stations have two, for a coverage arc of about 200°. Processing takes place on an adjacent computer." https://www.economist.com/science-and-technology/2024/07/24/how-ukraines-new-tech-foils-russian-aerial-attacks https://www.economist.com/science-and-technology/2024/07/24/... (2024) https://archive.is/sQcFO https://archive.is/sQcFO