Radar and AIS are often discussed together because both can improve situational awareness, but they do different jobs. Radar detects returns from objects around the vessel. AIS receives and, depending on the equipment, transmits identification and navigation information exchanged by AIS-equipped vessels and stations. Understanding that difference explains why one is not simply a substitute for the other.
What radar tells you
Marine radar can show returns from objects in the surrounding area, subject to the equipment, conditions, setup and the characteristics of the target. That can include vessels, land and other objects that produce a detectable radar return.
In New England, radar can be particularly valuable when visibility is reduced, but using it effectively requires understanding the display and settings rather than treating it as an automatic collision-avoidance system.
What AIS tells you
AIS can provide useful information about participating vessels, such as identity, position, course and speed when that information is being transmitted and received correctly.
Its limitation is fundamental: not every object on the water is an AIS target. Small boats, floating objects and other hazards may not transmit AIS information.
Why the systems complement each other
Radar can detect targets that do not transmit AIS, while AIS can provide identity and movement information that is not available from a basic radar return alone. When correctly installed and understood, the two sources can give the operator different perspectives on surrounding traffic.
Modern integrated navigation systems may display AIS information and radar data alongside electronic charts, making it easier to build a coherent picture.
Training matters
Technology is most useful when the operator knows what it is showing and what it is not showing. Navtronics provides onboard training as part of its service and support offering, which can help owners become more confident with the systems already installed on their boats.
Does AIS replace radar?
No. AIS depends on transmitted AIS data and does not represent every object or hazard. Radar and AIS provide different information.
Does radar identify a vessel by name?
A radar return alone does not provide the same identity information as AIS. Integrated displays may overlay or associate multiple data sources.
Is radar useful in New England fog?
Radar is widely used as an aid to navigation and situational awareness in restricted visibility, but it must be properly operated and should be used as part of safe navigation practices.
Need help with the system?
If you are considering radar, AIS or an integrated navigation upgrade, Navtronics can assess the existing system and help design an installation around the way you actually use the boat across New England waters.
Explore Navtronics’ navigation systems.