Subelement D: Display & Control Systems - 10 Key Topics – 10 Exam Questions— Topic 36: ARPA - CAS
Question 8-36D4
Element 8 (RADAR)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.
Explanation
On a radar display, a **vector** is a graphical representation used to predict a target's future position. It originates from the target's current position marker. The *length* of the vector is scaled to represent the target's speed over a specific time interval, while the *direction* of the vector indicates the target's course or true bearing of movement. This allows operators to quickly assess potential collision risks or target trajectories.
An Electronic Bearing Line (EBL) is used to measure the bearing to a target from the observer's vessel. A Range Marker indicates distance from the observer, often as concentric circles or adjustable lines. A Heading Marker simply shows the direction your own vessel is pointed. None of these options convey a target's speed or course through the length and direction of a line originating from the target itself.
Related Questions
8-36D2 What does the term ARPA/CAS refer to?8-36D3 Which of the following would not be considered an input to the computer of a collision avoidance system?8-36D5 What is the purpose or function of the “Trial Mode” used in most ARPA equipment?8-36D6 The ARPA term CPA refers to:8-37D1 The display power supply provides the following: