Radar ARPA Automatic Radar Plotting Aid Explained by City Sailing

ARPA - Automatic Radar Plotting Aid ARPA Automatic Radar Plotting Aid is a marine radar system that automatically detects, tracks, and predicts the movement of other ships and objects, providing vital data like speed, course, and Closest Point of Approach (CPA) for collision avoidance, reducing watchkeeper workload by automating target plotting. It requires a stabilised display and can be set to true or relative motion, but for collision avoidance relative motion is preferred. Automatic Radar Plotting Aid (ARPA) is a maritime navigation system that automatically tracks radar targets, calculating their speed, course, and closest point of approach (CPA) to enhance collision avoidance and situational awareness. It provides real-time data to replace manual plotting, reducing navigator workload and improving safety in dense traffic. Key Features and Functions Automatic Tracking: Detects and tracks up to 50 targets, providing continuous, rapid, and accurate evaluation. Collision Avoidance Data: Calculates target course, speed, and CPA (Closest Point of Approach) or TCPA (Time to Closest Point of Approach). Vector Modes: Offers Relative Vector mode for immediate collision risk assessment and True Vector mode for calculating the actual target course and speed. Trial Maneuver: Allows operators to simulate the effect of own-ship maneuvers on collision risks. Alarms: Provides audible and visual alerts for target acquisition, loss of target, and CPA/TCPA breaches. Operational Benefits Improved Safety: Reduces human error and provides faster, more accurate data than manual plotting. Efficiency: Enables quick assessment of multiple potential hazards simultaneously. Integration: Often integrated with ECDIS (Electronic Chart Display and Information Systems) and AIS (Automatic Identification System) for a comprehensive picture. Limitations Data Reliability: The accuracy of ARPA depends entirely on the accuracy of the speed log and gyro inputs. Target Swap: In high-density traffic, the system may occasionally swap target tracking between two closely spaced vessels. Delayed Information: It can take up to 3 minutes for a target's vector to stabilize and become accurate after a course change. Join this channel to get ALL of the RYA course work: https://www.youtube.com/channel/UCHHQH6jcgluqGjkqQf5iLkw/join