UNMANNED AIRCRAFT SYSTEMS IN CRITICAL INFRASTRUCTURE INSPECTION: A FIELD STUDY OF TELECOMMUNICATIONS BASE-STATION TOWERS
Telecommunications base-station towers support services that are indispensable to crisis communication, emergency response, public administration and economic continuity. Their dispersed location, height and lattice geometry make conventional close-access inspection hazardous, time-consuming and difficult to document consistently. This study evaluates the usefulness and limitations of uncrewed aircraft systems for inspecting steel lattice towers that form part of telecommunications critical infrastructure. A retrospective field study was conducted using records from inspections performed in 2022–2023 at 50 towers in three Polish provinces. More than 150 sorties were completed with a DJI Matrice 30T platform using optical zoom, thermal imaging, a laser rangefinder and georeferenced mission telemetry. Manual, column and spiral flight patterns were compared, while image sets were processed with photogrammetric software to support three-dimensional reconstruction and spatial localisation of defects. The observations show that uncrewed inspection is particularly effective for documenting coating damage, local corrosion, fastener deterioration, connection anomalies, snow or ice accretion and equipment requiring thermographic follow-up. Column flights generated the most detailed evidence but also the greatest processing burden; spiral flights were faster and better suited to screening and three-dimensional modelling. The study also identified important constraints: wind, battery endurance, vegetation, airspace restrictions, electromagnetic and navigation disturbances, and the need to protect sensitive infrastructure data. Uncrewed aircraft should therefore be treated as a risk-based screening and documentation tool integrated with engineering judgement and targeted close-contact or non-destructive testing, rather than as an unconditional replacement for statutory structural inspection.