What is crucial for the proper operation of GPS systems in aircraft?

The crucial factor for the proper operation of GPS systems in aircraft is clear access to the sky for satellite signals. GPS systems rely on signals transmitted from a constellation of satellites orbiting the Earth. These satellites communicate precise positioning information, which is essential for the GPS receiver to calculate its location accurately. If there are obstructions such as buildings, mountains, or even atmospheric conditions, the GPS receiver may not be able to receive strong signals from enough satellites, leading to inaccurate positioning or total loss of GPS functionality.

While maintaining communication with ground bases is important for some aspects of aviation, GPS technology fundamentally depends on satellite connectivity rather than direct ground communication. Regular software updates do help maintain accuracy and features of navigation systems, but they do not directly influence the immediate operation of GPS. Operational redundancy enhances safety and reliability within avionics systems but is not specific to the operation of GPS technology itself. Therefore, clear access to the sky for satellite signals is the defining factor that ensures GPS systems in aircraft function correctly.