Research Progress on Short-Time Auxiliary Propulsion Technology for Micro Unmanned Aerial Vehicles

Abstract

Micro unmanned aerial vehicles extend aerial sensing into spaces that are too small, dangerous or improvised for conventional aircraft. Their most vulnerable phase, however, is often the initial seconds of flight. Limited wing area, low-Reynolds-number aerodynamics and strict mass budgets make it difficult to combine efficient cruise with reliable launch acceleration. Short-time auxiliary propulsion addresses this mismatch by providing a brief, high-impulse launch stage while leaving the cruise system optimized for the mission. This review examines rocket-assisted take-off (RATO) as the most compact implementation of this concept, covering launch dynamics, booster-airframe integration, rail effects, separation reliability and system-level design. The literature shows a clear shift from isolated trajectory estimation towards coupled modelling of the aircraft, booster, launcher, and control system. Yet practical deployment remains constrained by mass penalties, thrust-line errors, centre-of-gravity migration, low-speed attitude sensitivity, separation safety, and regulation. Future progress will depend less on thrust magnitude alone than on predictable, modular and verifiable launch architectures.