TY JOUR TI Development of Visual Navigation Systems for Unmanned Aerial Vehicles in Environments Lacking GPS Signals KW visual navigation KW UAV KW GPS-denied environments KW simultaneous localization and mapping KW multiagent technologies JO Intellectual Technologies on Transport AU Zlobin, S.E. PY 2025 IS 0 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"