Instrument Rating Checkride Practice Test

What does FDE stand for in the context of GPS?

1. Fault Detection and Evaluation

2. Fault Detection and Exclusion

3. Frequency Detection and Exclusion

4. Function Data Evaluation

The correct answer is: Fault Detection and Exclusion

In the context of GPS, FDE stands for Fault Detection and Exclusion. This is a critical process used in satellite navigation systems to ensure the integrity of position information. When a GPS receiver calculates its position, it relies on signals from multiple satellites. If one of those signals is erroneous due to a fault in the satellite or in the signal itself, FDE is responsible for identifying and excluding that faulty satellite from the calculations. This process involves continuous monitoring of the signal characteristics received from the satellites and determining if any discrepancies indicate a fault. By excluding unreliable data, FDE helps maintain an accurate and reliable navigation solution for the user, which is of utmost importance, especially in safety-critical operations such as aviation. The other options do not accurately describe the function of FDE within GPS systems. For example, Fault Detection and Evaluation does not capture the specific action of excluding faulty data. Similarly, Frequency Detection and Exclusion and Function Data Evaluation do not pertain to the integrity monitoring aspect crucial for determining which GPS signals can be trusted. Therefore, recognizing FDE as Fault Detection and Exclusion is essential for understanding its role in ensuring reliable GPS performance.