Navigation General · GPS & GNSS
Which error source can cause a GPS position to appear displaced from its true location without any visible indication to the operator?
- ADilution of Precision (DOP) greater than 1
- BGPS spoofing, where false signals are transmitted to mimic genuine satellite signals✓ Correct
- CCold-start acquisition delay
- DLoss of WAAS/SBAS differential correction
Explanation
GPS spoofing involves broadcasting counterfeit GPS signals that a receiver processes as genuine, causing it to compute a false position with no alarm. DOP greater than 1 is not inherently a problem — poor geometry (high DOP) degrades accuracy but is usually visible to the operator via quality indicators. Loss of SBAS reduces accuracy but typically triggers a mode annunciation.
Authority: Bowditch (Pub. 9), Ch. 13
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