ARPA

Question 1

How long does ARPA take to produce reliable information after acquisition?

Answer 1

2-3 minutes assuming constant course and speed

Question 2

What is the function of the Trial Manoeuvre?

Answer 2

Gives a good understanding of the results of intended actions under rule 8

Useful in heavy traffic areas

Reduces the need for multiple course and speed alterations

Still actively tracks targets

Question 2

Problems within ARPA

Answer 2

Relies heavily on its input feed (will not question faulty input data)

Still suffers from range and bearing discrimination

Ice and small targets etc may not be acquired

Suffers from target swap

Over reliance

Effected by clutter

Does not readily show a targets change in course and speed

Question 2

ARPA alarms

Answer 2

Target has breached user-set CPA and TCPA

Tracked target is lost

An input failure (gyro, speed etc)

A target enters a guard zone (one that is not already tracked)

Picture freeze

Question 3

6 Items in order ARPA will show

Answer 3

Range
Bearing
Predicted CPA
Predicted TCPA
Targets True course
Targets True speed

Question 4

10 items of the IMO ARPA performance standards

Answer 4

Target swap should be minimised by design

Course and speed displayed in vector or numerical form

Data should not obscure other data on the display

Must have a trial manoeuvre function

Target tracking for 20 targets automatically, or 10 manually

Range and bearing quickly displayed

Predicted CPA, TCPA, True Course and Speed data shown (BCR, BCT, CCRP, CCCP are additional)

Must have accuracy to at least 1-3 minutes

Must be at least as accurate as manual plotting

STW must be able to be fed into ARPA