From the mailbag today:

quote:

REPORTS HAVE BEEN VERIFIED THAT SOME SAAB R3-AIS TRANSPONDERS, WHEN COMBINED WITH AN OLDER GPS RECEIVER, HAVE STOPPED WORKING WHILE GPS SATELLITE PRN32 IS IN VIEW. VESSELS AFFECTED ARE REPORTED BEING 'INVISIBLE' TO OTHER AIS EQUIPPED VESSELS IN ADDITION TO SOME AIS
EQUIPPED SHORE STATIONS. IT HAS BEEN REPORTED VESSELS EQUIPPED WITH THE SAAB R3-AIS TRANSPONDERS CONTINUE TO RECEIVE AIS INFORMATION FROM OTHER AIS EQUIPED VESSELS.

ALL VESSELS ARE ADVISED TO CHECK THE PROPER OPERATION OF THEIR AIS AND GPS EQUIPMENT. GPS PROBLEMS SHOULD BE REPORTED TO THE USCG NAVIGATION CENTER AT WWW.NAVCEN.USCG.GOV/GPS/USERINPUTGPS.HTM OR CONTACT THE USCG NAVIGATION INFORMATION SERVICE AT 703.313.5900.

I had rather seem stupid than continue to be stupid. What is AIS?

think IFF for boats, does that help?

Transponders, for posit/cse/spd and other things. Land units and other vessels with recievers can see your info independent of radar.

Helps a lot, Master Chief.

The ADS-B of the sea I suppose...

AIS stands for Automatic Identification System. It is a shipboard broadcast system that acts like a continuous and autonomous transponder, operating in the VHF maritime band. It allows ships to easily track, identify, and, exchange pertinent navigation information from one another or ashore; for collision avoidance, security and VTS reporting.

AIS technology relies on global navigation systems, navigation sensors, and digital communication equipment (i.e. transponders) operating according to standardized communication protocols that permit the voiceless exchange of navigation information between vessels and shore-side vessel traffic centers. AIS transponders on vessels can broadcast information about the vessel, such as its name or call sign, dimensions, type, position (derived from a global navigation system), course, speed, heading, navigation status and other pertinent navigation data. This information is continually updated, near real-time, and, received by all AIS-equipped stations in its vicinity. The advantage of this automatic exchange of information is that it is accessible to all, tailored to the mariner's needs, and greatly reduces voice radio exchanges. Through its national role in the International Maritime Organization (IMO), International Telecommunications Union (ITU), and participation in various other international working groups, including groups within the International Electrotechnical Commission (IEC), the Coast Guard has been a major contributor in the drafting and/or adoption of various technical standards (i.e. ITU-R M.1371, IEC 61993-2) required of a universal AIS.

On July 1, 2003, the Coast Guard published regulations, as required by the Maritime Transportation Security Act of 2002, requiring all vessels subject to the Safety of Life at Sea (SOLAS) convention and certain domestic vessels operating in Vessel Traffic Service (VTS) areas to install a ship-board AIS.

These following commercial domestic vessels, while transiting areas detailed below, must have an installed, operational AIS that complies with the standards for such devices adopted internationally and approved by the Coast Guard.

· Each self-propelled vessel of 65 feet or more in length, engaged in commercial service (including fishing)

· Each towing vessel of 26 feet or more in length and more than 600 horsepower

· Each vessel of 100 gross tons or more carrying one or more passengers for hire

· Each passenger vessel certificated to carry 50 or more passengers for hire