Which of the following best describes GPS spoofing mitigations?

• A. RAIM/FDE
• B. Multi-sensor checks
• C. Cross-checks with other nav aids
• D. All of the above

Answer: (D)

Mitigating GPS spoofing relies on layered checks that validate GPS data from multiple angles. RAIM with fault-detection and exclusion provides integrity monitoring within the receiver by using redundant satellite signals to detect inconsistencies in the ranging measurements and, if needed, exclude the suspicious satellites to preserve a reliable solution. This creates a built-in mechanism to flag or reject corrupted GPS info when the geometry and measurements don’t add up.

Adding multi-sensor checks strengthens this further by comparing GPS-derived position and velocity with independent sensors, such as inertial navigation systems or other onboard sensors. If GPS data is spoofed, these other sensors often reveal discrepancies, raising a red flag or allowing the craft to rely more on the non-GPS inputs until integrity is reestablished.

Cross-checking with other navigation aids provides an external verification against GPS-only solutions. By validating against VOR/DME, true airspeed and heading from inertial references, or other compatible nav references, you can detect inconsistencies that indicate spoofed data.

Together, these approaches cover internal integrity, cross-sensor consistency, and cross-sensor corroboration with external aids. That’s why the most robust answer is all of the above. It’s the combination of checks that gives the best protection against spoofing.