Thermal and Multispectral UAV Remote Sensing in Archaeology: A Systematic Review of Sensors, Platforms, Acquisition Contexts, and Processing Workflows (2013–July 2026)

Unmanned aerial vehicles (UAVs, or drones) carrying thermal-infrared (TIR) and multispectral (MS) sensors have become established instruments of archaeological prospection. Both are indirect, surface-proxy methods: they record radiance emitted or reflected by the ground surface or the plant canopy, and reach buried features only through the anomalies those features induce at the surface. This systematic review, reported in accordance with PRISMA 2020, maps that literature. Scopus, OpenAlex, Semantic Scholar and Google Scholar were searched on 27 July 2026 with a single Boolean string and no filters (590 records); an exploratory track using two large-language-model (LLM)-assisted deep-research assistants (Claude, Anthropic; ChatGPT, OpenAI) returned 168 further records. After deduplication, 380 unique records were screened by one reviewer and 22 further publications were added through citation searching; 132 publications, corresponding to 122 distinct research projects, were included. Sensor deployment is governed by surface regime: thermal-only studies operate on bare or arid surfaces in 47.6% of cases against 5.2% for multispectral-only studies (p < 0.001), confirming that two physically distinct detection pathways coexist in this literature. Thermal instruments identifiable as radiometric are the majority from 2017 onward, at 73–80% of determinable cases; 77.2% of multispectral studies (88.6% of those for which the array is identifiable) fly red-edge-capable hardware. Ground-geophysical integration increased from 0% in 2013–2016 to 5.9% in 2017–2020 and 26.4% in 2021–2026; the increase between the latter two periods was significant (Fisher’s exact test, p = 0.012). Reporting completeness, however, does not improve (mean 1.82, 2.68, 2.30 of 4; p = 0.029), and reporting of acquisition month falls from 64.7% in 2017–2020 to 31.0% in 2021–2026 (χ2 = 10.15, p = 0.0014). Platforms migrated to factory-integrated systems, with DJI (Da-Jiang Innovations, Shenzhen, China) equipping 59% of identified platforms. A minimal reporting standard is proposed.