NB: Nedenstående engelske afsnit om AIS er hentet fra: http://www.myboatsgear.com/newsletter/2007120.asp

En fin artikel som også indeholder links til diverse udstyr

Panbo 
is a site written by Ben Ellison electronics writer for Power & Motoryacht. 

Ben goes into much greater detail on all forms of electronics than anyone else I know. He is a big proponent of AIS.

Read his section on AIS

USCG Equipment Approval

USCG Navcen
You can read about AIS at USCG's navcen. 

Here you will have your questions answered about what is AIS, how it works, how its broadcasts, and types of AIS.

USCG Navcen MMSI information

Explains MMSI numbers

UAIS.org

Fred Pot runs UAIS and here you can get information on AIS. Get copy of AIS conference for ship operators in Seattle Nov 2002.

Sperrymarine

This is a ship version of AIS

SailWX

Automatic Identification System AIS

One of the fastest and biggest growth areas in marine navigation is AIS. Having an automatic identification system AIS transponder unit onboard, will turn your boat into a radio beacon continuously transmitting speed and course. Conversely having an AIS receiver allows you to track a ships COG, SOG. This can be very important information for navigating in shipping lanes and channels.

quick links

what is AIS,  what equipment do you need,  Class A AIS,  Class B AIS,  Class B AIS transponders,  Software,  Other sources of AIS discussion,  Other Collision avoidance devices

What is AIS

How does AIS work?

AIS has been a legal requirement on ships over 300GT for a while. Yachts with receivers can see those  vessels on a radar type plot. 

There are two types of AIS class A & class B. Class A is for Commercial shipping and transmits via 2 channels and typically is fully integrated into the ships navigation systems. Class B is for smaller vessels.

You can choose to receive only or receive and transmit, the later will give ships or any AIS receiver in your VHF range your COG, SOG.

Having discussed AIS with maritime industry workers including ship Captains and Pilots, I can tell you they really like the system. So does Panbo's Ben Ellison and many others in the marine Industry. My discussions with the Pilots concluded that while they like the system and believe it should be on many recreational vessels, they worry about too many signals in crowded channels. They would have to deal with lots of targets on their plotters which could be confusing.

The Biggest Benefit for having AIS  is for you to be able to figure out if you are on a potential collision course (CPA) see above diagram. So the suggestion is for recreational vessels to have the receiver only. Since Blass B transponders are still not approved in the US (April 2007 and still no approval) its a moot point.

The Difference between Class A and Class B is the transmission rates. Class A broadcasts every 2 seconds, while Class B is only very 30 seconds. This means for fast moving craft like high speed ferries you will get a ping twice a minute. At 20 knots the high speed ferry has moved quite a distance.

For Merchant traffic to see you on radar you need a reflector. Radar does not give you the same information that AIS does, also it is harder to read, while the AIS signal gives you precise information on the approaching vessel.

What do you need

 Navigation Software developer Nobletec's diagram below shows the AIS setup using the AIS 100 engine, the same setup would be appropriate for any AIS engine. You need a VHF aerial, a GPS, software and display. If you already have the VHF and GPS and a plotter, then adding the AIS unit could cost as little as $200. The AIS engine will send NMEA information to any AIS capable receiver. 

The same hardware setup would be used for a chartplotter depending on whether you use chart cartridges for a plotter or software with a PC.

You could also use a stand alone AIS unit like the NASA (Si-Tex in the US) one here. The screen will show you the targets in your VHF range.

The stand alone unit costs about $350. Much cheaper than radar.

Uses your existing GPS and VHF aerial.

There are discussions on VHF aerials which hinge on whether to have a separate aerial or to use your existing VHF aerial. Many find it is just as effective to use a splitter on the existing aerial. 

Now to the manufacturers producing AIS units

Class A units

This just one example from Simrad

Connected to radar or an electronic chart system, the AI80 provides a detailed overview of the shipping in your area. The vessel's primary GPS receiver needs to be interfaced with the AIS and is used as the main positioning source. However, the AI80 also incorporates an "all-inview" GPS receiver, which can be used as back up for the primary GPS receiver. The cost for this class A is in the $4,000 region.

Class B units receivers only

SI-TEX-NASA
Si-Tex sells NASA in the US

NASA make an AIS engine which receives only and is single channel. The engine has been popular as many  examples are outr there and is revievd both by Panbo and Practical-Sailor below. The engine can be bought for around $220 while the stand alone unit costs $400. You will need a GPS and Aerial.

Other suppliers of AIS receivers include;

Sealinks

Milltech

Maritec

TrueHeading

SeaCas

The Safepassage 300 is a self contained dual channel AIS receiver plus 16 channel GPS. GPS and AIS revivers are built into a 51" tall fiberglass aerial. COG and SOG are updated every 10 seconds. Look at SeaCas list of compatible software and hardware, which is a list of who's who in the industry. Cost approx, $1,300.

Simrad A150

Simrad's new AIS class B, the A150 retails for £800 or $1,600. The first color AIS class B unit. This unit receives and transmits data (not in the USA) but is good in Europe. The daylight viewable color screen and easy interface with built in coastal maps make for simple watch keeping. Range rings allow for setting of alarms to warn of incoming traffic. The unit connects through NMEA 200 based SimNet marine network. For DSC capability connect to a SimNet equipped DSC radio and call via the MMSI number of the selected boat. Buddy tracking allows you to track 3 friends.

Standard Horizon

Standard Horizon Chartplotters are now AIS compatible. Previous models can be upgraded.

The CPV350 is capable of displaying AIS signals (when optional AIS receiver connected) as Targets on the chart page in relation to your position. In addition the CPV350 can be setup to alarm when a target ship is within a specific time or range zone, to alert you to avoid a collision. 

RayMarine

Raymarine, Inc. announced at the Miami International Boat Show its AIS250 Automatic Identification System Receiver Module.

Raymarine's AIS250 Receiver module is a "listen only" AIS receiver that easily integrates with an existing VHF antenna using a built in VHF splitter. The AIS250 then interfaces to Raymarine's displays, allowing nearby targets to be graphically overlaid in both the chartplotter and radar modes. The AIS250 also receives broadcasts from shore stations, including AIS alarm and safety-related messages from sources such as the U.S. Coast Guard. Raymarine's AIS250 features the ability to monitor both class A and B AIS broadcasts, and two NMEA 0183 input output ports with a built-in multiplexer. The AIS250 is expected to be available in May 2007. The AIS250 is a single reciever for $1,120.

Class B units Transponders

Note; Most class B transponder units are awaiting FCC approval. Comar below is one of the first to get class B certification in Europe.

There is still no FCC approval for transponders in the US. 10/12/07

update 7/1/08

Shine Micro may have a short term answer to the FCC

We have been waiting in the US for the FCC to allow Class B AIS units for some time. At present we can purchase receive only AIS units. This is still a good option as the AIS receive only units allow you to pick up any ships AIS broadcast in you area. The AIS broadcast will give you the ships COG and SOG which can be plotted on your chartplotter. Simple observation of the chartplotter gives you a handle on ships movement in your area. When Class B is allowed you can broadcast your AIS signal.

Shine Micro has come up with a solution for those waiting for Class B approval. By the RadarPlus now for $799 and when Class B is approved you can get it activated for an additional $200.

Shine Micro's Description

RadarPlus AIS-BX Class B AIS in Receive-Only Mode $799.00 USD

Class B AIS is a low cost safety of navigation aid. With the RADARPLUS® AIS-BX you can transmit vital data about your vessel while viewing the AIS transmissions of others in real-time. In addition, Shine Micro is an FCC approved issuer of the Maritime Mobile Service Identification number required for identifying your vessel, and provides this unique ID number free with your purchase. The assignment of your MMSI, or registration of an existing one, is online*; making activation easy. Transmit Your Position Operating an AIS-BX ensures you are seen by other AIS fitted vessels, including the U.S. Coast Guard, Search and Rescue Operations and most commercial ships. Safety Related Message If configured accordingly, the Safety Related Message button allows the user to transmit a distress alert quickly and easily to all vessels and base stations within range. By default the AIS-BX is programmed to engage "Silent Mode" when the "S" button is pressed. Note: The SRM feature is in addition to the international AIS specification and may not be monitored by all reception equipment. This feature does not replace use of normal VHF emergency procedures. Internal GPS The AIS-BX includes an integral 16 channel GPS. Standard NMEA Interface The AIS-BX can interface with any NMEA compatible GPS plotter or suitably configured PC. Water Resistance An IP65 rated aluminum case ensures that the AIS-BX is able to operate in harsh environments. Online Activation* *Assign or register your MMSI number and activate your transponder online at www.shinemicro.com, or contact us to receive the forms via email or fax.

Comar

Comar's new CSB200 Class B AIS. Connected to a compatible on board PC running a Navigation Program, or Chart Plotter, information received from other vessels or shore stations can also be displayed on screen giving the skipper or navigator a visual interpretation of the name, position, course and speed of vessels within VHF range. This information is updated every 3 seconds to 6 minutes depending on speed and rate of turn, enabling the track of the vessels in range to be plotted. Cost about $1,200. The receiver switches channels every minute. Comar has a single frequency AIS listener SLR100 for approx $540. 

ACR
Nauticast Class B AIS unit should cost in the $1,000 region once approval has been passed. 

The see through casing is interesting and I guess it allows the lights to be seen without compromising water tightness. Looks cool though. 

Software

Memory Map

AIS on your PDA that's cool, it will work on your PC also like other navigation  software. 

You will need an AIS receiver plus GPS and an aerial. 

See list of compatible hardware.

If you already have software check your manufacturer to see if they have AIS compatibility. I would think there is an upgrade.

Other discussions on AIS

Practical Sailor

Subscription required but highly recommended.

Each month many topics are covered and the February 2007 edition has a test of the NASA engine. They say it works as advertised but they would like to see improvements in some of the keys.

Yacht Valhalla

Terry Sargent has many articles on his site including a detailed account of his use of AIS. Very Interesting reading from a user. He discusses AIS engine,  software, antennas and antenna location. Plus some interesting experiences.

Other Collision Avoiding Products

Raymarine showing MARPA

MARPA is an acronym for Mini Automatic radar Plotting. If you have a suitably equipped Radar you place the cursor over the target and then tell the system to acquire the target. The radar will analyze the data and reproduce the target as a track on the screen showing COG, SOG and CPA.

Radar Flag

Link to AIS section

Scuttlebutt