Emerging and established topics in drone research: Citation impact and knowledge flows across China, the United States, the EU, Ukraine, and Russia (2020-2025)

Abstract

This study examined emerging and established topics in drone research, focusing on citation impact and knowledge flows across China, the United States, the EU, Ukraine, and Russia between 2020 and 2025 using OpenAlex bibliographic data. The findings revealed that drone-related science is characterised by growing geopolitical asymmetries in scientific production, citation concentration, and international knowledge exchange. In particular, China increasingly dominated scientific production, fractional authorship contribution, and domestic citation circulation. In contrast, the United States and EU countries maintained comparatively more internationally distributed citation structures. However, China-affiliated publications became increasingly integrated into global citation networks, particularly through growing citation exchange with the United States and European countries. Notably, the interpretation of authorship and citation patterns was complicated by the high proportion of publications with unidentified affiliations, which reached 50% in 2025 within weak-signal topics. These findings underscore the importance of developing comprehensive national Research Organisation Registries (RORs). Although China demonstrated a citation advantage, this was partly driven by high internal domestic citation concentration rather than exclusively by global integration. Moreover, China still imported proportionally more knowledge from the EU-14 and the United States than it exported, with this asymmetry increasing over time. EU-14 countries maintained the strongest citation impact in weak-signal topics, suggesting a more prominent role in shaping emerging research directions. At the same time, China-affiliated publications cited the United States more frequently than the EU-14 in both strong- and weak-signal topics, with this pattern being particularly pronounced in weak-signal areas.