Class B AIS

[JDCAVE]

I have just purchased the Sitex metadata Class B AIS unit. A Wikipedia article on the subject states "...Although the data output format supports heading information, in general units are not interfaced to a compass, so this [sic] data is seldom transmitted." Does this mean that ships in receipt of my signal will not receive my bearing information and vector? I would have thought that COG would be integrated from the vessel's GPS information.

I have an a AIS receive only unit and all ships signals I receive show heading information, unless that vessel is stationary. Surely some of the pleasure craft would have class B units.


Jim
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[N4712]

It will use COG if not heading data is available, mainly the heading is for when the boat is stationary so your showing correct orientation but it's not a big deal.

 

[ulysses]

Information obtained is from the GPS (Not Compass) usually providing your COG and SOG. It will provide a bearing and distance. There are both static and dynamic info. provided to other receivers If you are not moving the "dynamic" information is suspect and cannot be determined. In other words the gps does not know what direction you are pointed but does know where you are. Bear in mind that all of the internet tracking sites use contracted antenna either on other vessels or land based to receive their data which is effected by line of sight and locations. Other vessels within line of sight will received your data more readily than perhaps the land based or contracted ship antenna.

 

[JDCAVE]

Thanks guys. That confirms what I had previously thought.


Jim
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[twistedtree]

And you can feed heading into the AIS if you feel so motivated. Is the AIS N2K connected? If so, and if your heading sensor (likely from your AP) is also on N2K, then it should get to the AIS. The same is also possible via 0183 depending on how you connect the AIS info into your other devices. Happy to provide more guidance if you want to do this. It all depends on how your boat is wired up.