Radar Observer · Navigation — Target Identification
Before using a radar echo as a navigation fix reference, the navigator must:
- AUse only the echo nearest the center
- BAssume the strongest echo is the intended landmark
- CPositively identify the echo with a charted feature (and beware of low/poor radar targets and distorted coastlines)✓ Correct
- DSwitch to head-up orientation
Explanation
Coastlines on radar are distorted (low/sandy shores return weakly, the radar 'shoreline' may be inland of the true coast, and small craft or buoys make poor targets), so an echo must be positively correlated with a charted, radar-conspicuous feature before it is trusted for a fix. Racons and isolated steep features help.
Authority: Bowditch (Pub. No. 9), Radar Navigation
Practice the full Radar Observer bank
Free spaced-repetition quizzing across 2550 USCG exam questions — it schedules your reviews so the ones you miss come back until they stick.
Related Radar Observer questions
- Display — Motion
On a relative-motion radar display, your own ship is:
- Collision Avoidance — CPA
The closest point of approach (CPA) of a radar target is:
- Collision Avoidance — TCPA
TCPA on a radar/ARPA readout represents the:
- Controls — EBL
The electronic bearing line (EBL) on a radar is used to:
- Controls — VRM
The variable range marker (VRM) on a radar measures:
- Controls — Clutter
The anti-clutter sea (STC / sensitivity-time control) is adjusted to: