What is the purpose of a Ground Power Unit (GPU)?

The purpose of a Ground Power Unit (GPU) is primarily to provide electrical power to an aircraft while it is on the ground. This is particularly important for maintaining the aircraft's systems and supporting functions such as lighting, avionics, and environmental control when the aircraft's engines are not running. By supplying power externally, the GPU allows for various pre-flight checks, maintenance activities, and ground operations to take place without relying on the aircraft's own power sources, which conserves fuel and extends the lifespan of the aircraft's batteries.

Given this function, the other options do not align with the primary purpose of the GPU. Assisting in baggage delivery, conducting flight operations from the ground, and managing passenger boarding processes pertain to different operational aspects within airport logistics and do not involve the provision of power to aircraft systems.