CMRT Target Tracking & ARPA Flashcards

What initial data does ARPA require from its own-ship sensors to compute accurate target tracks?

Answer: Own ship's speed and heading

ARPA needs own-ship heading (from gyrocompass) and speed (from log or GPS) to resolve relative target motion into true target motion.

How long does IMO performance standard require an ARPA to establish a steady-state track on a new target?

Answer: Within 1 minute for 10 knots and within 3 minutes for all targets

IMO standards require ARPA to display a target's predicted motion within 1 minute for targets on steady courses at up to 10 knots, and within 3 minutes for all other targets.

A technician notices ARPA vectors consistently point in incorrect directions even though targets are correctly positioned. Which sensor is most likely faulty?

Answer: Gyrocompass heading sensor

Incorrect vector directions with correct target positions indicate a bad heading input, because the ARPA uses heading to convert relative to true bearings.

What does 'acquisition' mean in the context of ARPA?

Answer: The process of selecting a radar return and beginning to track it

Acquisition is the process by which the ARPA selects a radar echo (manually or automatically) and initiates a tracking algorithm on it.

In a sea-stabilized ARPA display, a target's vector shows the target moving directly toward your vessel. What does this indicate?

Answer: The target is on a collision course with zero CPA

A true vector pointing directly at own ship in sea-stabilized mode indicates the target is heading straight for you, yielding a CPA of zero.

What is the primary advantage of AIS integration with ARPA in a modern radar system?

Answer: AIS provides vessel identity and voyage data to correlate with tracked radar targets

Fusing AIS data with ARPA tracks allows the operator to associate a target's name, MMSI, and voyage info with the radar return.