Launching unmanned aerial vehicles

A system for launching an unmanned aerial vehicle (UAV) to deliver goods to a destination, said system comprising:

• a lifting arrangement which is physically separate from the UAV and powered by a power source, the lifting arrangement being operable, before launch of the UAV, to vertically elevate the UAV to a selected altitude relative to a reference level;
• and
• a control system configured to calculate the selected altitude and provide a corresponding control signal for the lifting arrangement,
• wherein the control system is configured to calculate the selected altitude as a function of parameter data representing at least one of the UAV, the lifting arrangement, or surrounding conditions between the lifting arrangement and the destination, and
• wherein the parameter data comprises one or more of topography data for a region comprising the lifting arrangement and the destination, current ambient data of the region, current weight data for the UAV, current size data for the UAV, current energy content data of a local power source in the UAV, current energy content data of the power source, or elevation speed data of the lifting arrangement.