Fig. 1
Result of initial literature search in the research publication database Scopus_com, performed March 2020
| Search string | Total | Engineering | Social science | Management | Multi-disciplinary |
|---|---|---|---|---|---|
| (Autonomous OR unmanned) AND (surface OR underwater OR maritime) AND (system OR vehicle) | 30,167 | 20,960 (69%) | 1,163 (4%) | 292 (1%) | 239 (1%) |
| (Autonomous OR unmanned) AND (surface OR underwater OR maritime) AND (system OR vehicle) AND (military OR defence OR defence) | 1,700 | 1,309 (77%) | 69 (4%) | 124 (1%) | 11 (0.1%) |
| (concept development) | 3,763 | 1,574 (42%) | 746 (20%) | 282 (7%) | 13 (<0.01%) |
| (concept development) AND (military OR defence OR defence) | 127 | 81 (35%) | 18 (8%) | 12 (5%) | |
| Innovation AND military | 3,263 | 1,226 (23%) | 844 (16%) | 389 (7%) | 22 (<0.01%) |