Subelement D: Display & Control Systems - 10 Key Topics – 10 Exam Questions— Topic 36: ARPA - CAS
Question 8-36D2
Element 8 (RADAR)What does the term ARPA/CAS refer to?
Explanation
ARPA (Automatic Radar Plotting Aid) and CAS (Collision Avoidance System) refer to advanced features integrated with marine radar systems. Their primary purpose is to assist navigators in preventing collisions by automating the process of target tracking.
These systems automatically **acquire and track targets** detected by the radar, calculating critical information such as the target's course, speed, closest point of approach (CPA), and time to CPA (TCPA). This processed data is then displayed visually, typically as vectors or symbols, on the radar indicator's CRT (or modern LCD screen), enabling the operator to quickly assess collision risks and make informed decisions.
Option A is incorrect because ARPA/CAS is an advanced *enhancement* to a basic radar system, not the basic system itself. Option B describes only a display function and is overly specific; ARPA/CAS's core is the processing and tracking. Option D is incorrect because ARPA/CAS provides crucial decision-making information to the human operator but does not automatically steer the vessel.
Related Questions
8-35D6 What is the primary purpose of display system memory?8-36D1 The ship’s speed indication on the ARPA display can be set manually, but does not change with changes in the vessel’s speed. What other indication would point to a related equipment failure?8-36D3 Which of the following would not be considered an input to the computer of a collision avoidance system?8-36D4 Which answer best describes a line on the display which indicates a target’s position. The speed is shown by the length of the line and the course by the direction of the line.8-36D5 What is the purpose or function of the “Trial Mode” used in most ARPA equipment?