Navigation General · GPS & GNSS
The horizontal datum to which modern GPS positions are referenced is:
- ANAD 27
- BWGS-84✓ Correct
- CMean Lower Low Water
- DThe local harbor datum
Explanation
GPS positions are referenced to the WGS-84 datum. When plotting GPS positions on a chart drawn to a different datum (e.g., an old NAD 27 chart), the datum-shift note on the chart must be applied, or the position can be off by hundreds of meters.
Authority: GPS; chart datum notes
Practice the full Navigation General bank
Free spaced-repetition quizzing across 2190 USCG exam questions — it schedules your reviews so the ones you miss come back until they stick.
Related Navigation General questions
- GPS & GNSS
GPS determines a receiver's position by measuring:
- GPS & GNSS
Which error source can cause a GPS position to appear displaced from its true location without any visible indication to the operator?
- GPS & GNSS
Selective Availability (SA), the intentional degradation of GPS civilian signals, was:
- GPS & GNSS
Multipath error in GPS occurs when:
- GPS & GNSS
WAAS (and similar SBAS) improves GPS accuracy by:
- GPS & GNSS
A prudent navigator treats a GPS position as: