Radar Observer · Integration — AIS vs Radar
A sound practice when an AIS target and a radar/ARPA target for the same vessel are both available is to:
- AAcquire only targets with AIS
- BTrust AIS alone and stop using radar
- CIgnore AIS entirely
- DUse them together but treat radar as the primary anti-collision sensor, since AIS data depends on the other ship's correct input and transmission✓ Correct
Explanation
AIS adds identity and the other ship's reported course/speed, but it can be wrong (bad input, not transmitting, or absent on small craft), so it must not be the sole basis for collision avoidance. Radar/ARPA detects all reflective targets independently and remains the primary sensor; the two are best used to cross-check each other.
Authority: Navigation Rules Rule 7; IMO guidance on AIS
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: