True Vector vs Relative Vector: A Guide to Collision Prevention and Safe Navigation l Marine RADAR

This video shows how to interpret a displayed vector on the RADAR/ARPA for collision avoidance. It covers the True & Relative vectors when the radar is in Relative motion, Sea Stabilized mode.
True Vector displays the actual movement of a target in relation to a fixed point on Earth. It shows the true course and speed of the target, and it gives a real-world depiction of a vessel’s path over the ground.
Relative Vector represents the movement of a target in relation to the motion of the observing ship or own ship. It shows how the target is moving relative to your own ship’s position and speed. This is useful for collision avoidance, as it indicates how a target’s position changes with respect to your own vessel.
In short, True vector shows a target’s movement over the ground, while Relative vector shows how the target moves relative to your own vessel.
#radar
#colreg
#collisionregulation
#navigation
#passageplanning
#seamanship
#maritime
#seafarer
#seaman
#bsmt
#maritimestudents
• Radar Techniques: Grou...

[@mustaphakamikas2274]

well done sir , Thx !

[@nauticalacademy001]

You are welcome! Thanks.

[@rahulghosalkar8159]

Very nice video.
Please cover all other equipments also like Speed log, AIS etc for SIRE 2.0 consideration.

[@nauticalacademy001]

Thank you. I will try to make video of other equipment in the future. Thanks

[@searchformeaning85]

Do RADARs provide target "aspect" information?

[@nauticalacademy001]

Modern RADAR systems can provide target aspect information, but not all RADARs offer this feature directly. Aspect refers to the orientation of a target relative to your ship, essentially indicating whether the target is moving towards, away from, or across your position. RADAR systems equipped with Automatic Radar Plotting Aid (ARPA) or similar tracking capabilities can estimate the target's course and speed over ground, which can help you determine the target's aspect. However, this is often inferred from the tracking data, not a direct measurement from the RADAR.
In simpler RADAR systems without ARPA or advanced tracking, aspect information isn't directly provided, and you would need to manually interpret it based on the target's movement over time relative to your own ship's position.
In true vector mode, the vectors shown on the radar display represent the true course and speed of both your vessel and the targets relative to a fixed point (usually the Earth or a reference point on the ground). While this gives you the true motion of the target, aspect refers to the orientation of the target relative to your ship (i.e., whether the target is facing towards or away from your vessel). To determine the target's aspect, you would still need to analyze the target's course and compare it to your own vessel's position and movement. The radar’s true vector mode helps by providing accurate course and speed data, but it doesn’t directly display the target's aspect.
True vector mode gives you more precise information about the target's movement, which can assist you in determining its aspect, but it doesn't automatically display the aspect itself. You would still need to analyze the target's course and compare it to your own vessel's position and movement.

[@searchformeaning85]

@@nauticalacademy001 Thanks for your reply. Please, add more videos with scenarios on how to interpret and/or avoid misinterpretation of the PPI