What is the function of telemetry in a UAS?

Telemetry in a UAS plays a crucial role by enabling real-time transmission of flight data to the ground control station. This function allows operators to monitor various parameters such as altitude, speed, battery level, and location during a flight. The real-time data is essential for making informed decisions and adjustments while the aircraft is in operation, ensuring not only the efficiency of the flight but also the safety of the UAS and any surrounding entities.

In comparison to the other options, recording flight details for maintenance tracking is a valuable practice but is not the immediate function of telemetry. Telemetry focuses more on the live data transmission aspect rather than post-flight analysis. Categorizing airspace for safe navigation is a function of regulatory processes and air traffic control rather than telemetry itself. Lastly, providing a visual line of sight is important for the operator's control and legal compliance but is a separate aspect of UAS operations that does not involve the transmission of data. Thus, option B clearly captures the essence and primary role of telemetry within unmanned aircraft systems.