CMRT CMRT Target Tracking & ARPA 1 — Questions and Answers
Question 1: What does ARPA stand for in the context of marine radar systems?
- Automatic Radar Plotting Aid (Correct answer)
- Advanced Radar Processing Algorithm
- Automated Range and Position Analyzer
- Analog Radar Processing Array
Correct answer: Automatic Radar Plotting Aid
ARPA stands for Automatic Radar Plotting Aid, a system that automatically tracks targets and computes their motion vectors.
Question 2: Which parameter does ARPA calculate to determine collision risk with a tracked target?
- Closest Point of Approach (CPA) (Correct answer)
- Maximum Range of Acquisition (MRA)
- Bearing Resolution Index (BRI)
- Pulse Repetition Frequency (PRF)
Correct answer: Closest Point of Approach (CPA)
ARPA calculates CPA (Closest Point of Approach) and TCPA (Time to CPA) to assess collision risk with each tracked target.
Question 3: What is the minimum number of targets an ARPA system complying with IMO Resolution MSC.192(79) must be capable of tracking simultaneously?
- 100 (Correct answer)
- 20
- 50
- 10
Correct answer: 100
IMO Resolution MSC.192(79) requires ARPA systems to track a minimum of 100 targets simultaneously.
Question 4: In ARPA terminology, what is 'target swap'?
- A tracking error where the system exchanges the identity of two nearby targets (Correct answer)
- A manual reassignment of a target to a different tracking channel
- A deliberate override of automatic acquisition
- A calibration procedure for the tracking algorithm
Correct answer: A tracking error where the system exchanges the identity of two nearby targets
Target swap occurs when two closely spaced targets pass near each other and the ARPA incorrectly exchanges their tracked identities.
Question 5: What is the purpose of the 'guard zone' feature in an ARPA/radar system?
- To automatically alarm when a target enters a defined range or sector (Correct answer)
- To block radar emissions in a specified direction
- To filter out sea clutter within a set distance
- To limit the radar's detection range for power saving
Correct answer: To automatically alarm when a target enters a defined range or sector
A guard zone triggers an alarm whenever a radar return or tracked target enters the user-defined range ring or sector area.
Question 6: Which ARPA display mode presents all tracked target vectors relative to the water rather than the ground?
- True Motion – Sea Stabilized (Correct answer)
- Relative Motion – North Up
- True Motion – Ground Stabilized
- Head-Up Unstabilized
Correct answer: True Motion – Sea Stabilized
Sea-stabilized true motion removes own-ship movement through the water, showing target vectors relative to the water mass.
CMRT CMRT Target Tracking & ARPA 1
What does ARPA stand for in the context of marine radar systems?