What is a stepwise SEW response plan for GNSS spoofing during critical operation?

• A. Continue operation while ignoring spoofing signals.
• B. Stepwise plan: detect spoofing via RAIM and cross-check, switch to inertial navigation and alternative sensors, execute fail-safe procedures, coordinate with SDA, communicate with operators, log events.
• C. Shut down all navigation sensors and halt operations.
• D. Switch immediately to the strongest GNSS signal.

Answer: (B)

Handling GNSS spoofing in critical operations relies on a layered response: detect, mitigate, and maintain safety while preserving mission continuity. Start with integrity checks such as RAIM and cross-checks across available GNSS signals to determine if the received data is trustworthy. If spoofing is indicated, switch the navigation solution away from GNSS immediately to inertial navigation and other trusted sensors, so you aren’t relying on potentially corrupted position or timing data. Then execute predefined fail-safe procedures—degrade gracefully, switch to a safe operating mode, and use alternative timing sources as needed—to reduce risk without plunging the system into an unsafe state. Coordinating with Space Domain Awareness helps confirm the threat and re-task assets if required, while keeping operators informed ensures informed decision-making. Finally, log all events for post-event analysis and future improvement. This stepwise approach minimizes disruption, preserves control, and prevents acting on spoofed information, unlike continuing operations with spoofed data, shutting everything down, or blindly switching to the strongest GNSS signal.