e-navigation, ECDIS, training and consultancy

Renaissance for the radar overlay?

In the early days of electronic chart systems, before full GPS coverage, radar overlays were used to correct the ship’s position on an electronic map. It was used to compensate for the error using Loran C, Decca, or Transit satellite systems. The operator could simply align the map with an overlaid radar picture.

Today, the maritime community has warned against an “over-reliance on the GPS position on an ENC map.” This has resulted in a general requirement to create regular lines of position (LOPs) or optical bearings in the ECDIS. This task is a heavy-load working method that sometimes requires an extra navigation officer on the bridge.


Radaroverlay. Image credits: ECDIS900

The radar overlay can be used as a second positional input instead of optical bearings. It can provide the officer on watch with a high quality video image containing more than 1000 bearing (LOPs) with distances for each radar antenna rotation. All together, this will be a radar image overlaid on the ENC map that also gives the exact navigation error as it currently exists. Best of all, it is fully automatic and needs no extra navigation officer on duty.

Radar overlay has now been implemented into my training courses. Besides a general explanation of the principles of the PC Radar kit, how it works, and how to operate it, the students will be able to study two new practical exercises:

  1. Using the radar overlay to view the ship’s navigation instrument errors.
  2. Using the radar overlay in areas with high traffic density.

Obviously, the maritime community want ships to use more than one type of positioning system as input for the ECDIS. In fact, this may encourage a renaissance for products like the radar overlay. Methods like this give the ECDIS operator an easily understandable picture of the current location of the ship and the kind of navigation error that exist.

The radar simulator and the associated training will provide students with a better understanding of the features of the PC Radar Kit 6.0 and give them a high quality radar image to work on.

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