RADAR domes (or, radomes) describe self-contained units that emanate RADAR waves without exposing any moving parts, while "open array" systems describe larger units that sweep much larger arcs, so they tend to be more accurate than smaller self-contained radomes. Unfortunately, open array systems require a lot more open space so they can openly rotate, and they are much more suited to larger vessels or power boats where they can be easily mounted.

For more information, please read our FAQ on Radar