GPS information may not be available at times due to which factors?

• A. Mountains shadowing satellites.
• B. Jamming.
• C. High dynamic maneuvers.
• D. All of the above.

Answer: (D)

GPS availability hinges on having a clear view of enough satellites and the receiver’s ability to track their signals reliably. Mountain terrain can block the line-of-sight to satellites, causing shadowing where no satellites are visible. Jamming or other interference can overwhelm or corrupt the signal, preventing a valid fix. High dynamic maneuvers introduce rapid changes in signal characteristics, like Doppler shifts, which can challenge the receiver’s tracking loops and momentarily break lock. Because any of these situations can prevent a reliable GPS fix, all of the above factors can lead to GPS information not being available.