Which system component is used to reposition the antenna reflector based on error signals?

The Closed Loop Servo System is the correct answer because it is specifically designed to monitor and control the position of the antenna based on feedback from error signals. A servo system utilizes sensors to detect the position of the antenna and compares it to a desired position. If there is a discrepancy, the system processes this error signal and adjusts the antenna's position accordingly. This continuous monitoring and adjustment are what defines a closed-loop system, ensuring precise control over the antenna's alignment for optimal performance.

In contrast, while the Motor Controller Card and Tilt Drive Assembly play roles in operating the mechanical parts of the antenna system, they do not inherently provide the feedback loop necessary for real-time repositioning based on error signals. The Power Supply Inverter Group, on the other hand, is primarily responsible for providing the necessary power for the system's operations but does not directly involve the management of antenna positioning.