Remotely Piloted Aircraft Systems (RPAS) for Monitoring Archaeological Sites in Nunavik in the Face of a Changing Climate

Over the last century, remote sensing has proven effective in recognizing and studying cultural heritage in various geographic and chronological contexts, and the use of Remotely Piloted Aircraft Systems (RPAS) has become an integral part of archaeological research. In this paper, we explore the potential of RPAS equipped with photogrammetry and LiDAR sensors to identify archaeological features covered by vegetation and produce high-resolution models to document sites threatened by climate change (i.e., coastal erosion, forest fires, and shrubification). In 2023, we conducted remote sensing surveys at seven archaeological sites located in two different areas of Nunavik (Northern Québec, Canada), producing orthomosaics, Digital Surface and Terrain Models (DSMs and DTMs), and 3D models. The analysis of such products highlights the effectiveness of photogrammetry in recording sites affected by coastal erosion and features recently cleared by forest fires. In addition, we show that LiDAR sensors can help to locate archaeological features hidden by shrubs; however, in cases where the vegetation is exceptionally dense, even LiDAR struggles to identify anthropogenic features.近一个世纪以来，遥感技术在不同地理与年代背景下的文化遗产识别与研究中已被证实成效显著，而遥控航空器系统（Remotely Piloted Aircraft Systems, RPAS）的应用也已成为考古研究中不可或缺的组成部分。本文探讨了搭载摄影测量与激光雷达（LiDAR）传感器的RPAS在识别植被覆盖下考古遗迹方面的潜力，以及构建高分辨率模型以记录受气候变化（即海岸侵蚀、森林火灾与灌丛扩张）威胁的遗址的可行性。2023年，我们在加拿大魁北克北部努纳维克地区的两个区域内的7处考古遗址开展了遥感勘测，生成了正射影像图、数字表面模型（Digital Surface Models, DSMs）与数字地形模型（Digital Terrain Models, DTMs）以及三维模型。对上述成果的分析表明，摄影测量技术在记录受海岸侵蚀影响的遗址以及森林火灾后裸露的遗迹方面效果显著。此外，我们证实激光雷达传感器可辅助定位被灌丛遮蔽的考古遗迹；但在植被异常茂密的情况下，即便激光雷达也难以识别人工遗迹。