AIS receivers provide much of the coverage on the AIS Fleet map. If you have one aboard your boat or on a shore mast, it can contribute reports to that network. Those reports help update vessel positions and departure and arrival notices, including in places with little other coverage.

AIS Fleet calls each receiver you share a station, and lists them under My Stations. Sharing is free on every plan, with no limit on how many you run.

What sharing grants, before you wire anything up

No other member sees the station. Its name, its position and even whether it exists stay hidden from them, and nothing on AIS Fleet says which station reported a vessel.

The vessels it hears become part of what AIS Fleet knows. They are drawn for every member, they feed the departure and arrival notices, and they are included in the vessel data we license to other software and to the partners we supply, as section 3 of the Terms sets out. That permission covers reports already sent and continues if you stop sharing.

Adding a station is also what the Terms are asking you to accept, which is why you may have been asked to read them again.

A station whose figures reach the bar for a month earns Plus or Pro for the month after; the bar and the counting are under How to get Plus or Pro for free.

Your phone as a station

If you use the AIS Fleet app on an iPhone on your boat's Wi-Fi, connect your receiver under You > AIS receivers and the app becomes a station of its own. Sharing is on as soon as you add your first receiver; on an iPhone where someone else added the receivers, sharing starts off when you sign in. To pause it on an iPhone, open You > AIS receivers there and switch off Share with AIS Fleet: that iPhone then sends nothing from its receivers to AIS Fleet, while the receivers and the chart keep working normally. Disconnecting or removing the receiver also stops its reports.

The app's station appears under My Stations, under the name the app gave it. On the website you can rename it or remove it. After a removal, sharing turns off on each iPhone the next time it tries to report, until you switch it back on there. The app's row cannot be switched off on the website: use Share with AIS Fleet on each iPhone.

The app reports everything it reads as one station, however many receivers are connected, and your account has just one app station. Signing out and back in keeps it, with its figures, and any other iPhone signed in to your account sends its reports to the same station while it is sharing. Each iPhone has its own Share with AIS Fleet switch, so switching sharing off on one leaves the others sharing. To stop all sharing from the app, switch off Share with AIS Fleet on every iPhone.

AIS Fleet on your phone covers what the app does with a receiver, including drawing what it hears directly rather than through the network.

Add a receiver

1. Open aisfleet.com/stations and sign in if asked. It is also My Stations in the account menu.
2. Choose Add a station, then An AIS receiver.
3. Under Connection, leave UDP chosen for a receiver, plotter, gateway or program that forwards NMEA 0183; choose API token for software of your own that sends reports itself (Your own software below).
4. Give it a name you will recognise, such as "Masthead" or "Shore mast", and choose Add receiver.

If your receiver's setup page opens Connect this receiver, check Signed in as before continuing. To choose another account, use Use another e-mail; Connect and Cancel wait while you are being signed out. If sign-out cannot be confirmed, the page keeps your entries and offers a retry.

A receiver connected this way receives its UDP address automatically, so there is nothing to type in. You can see the address under Settings on the station's page. The station's row under My Stations shows the receiver's serial number. When the receiver reports its firmware version, the row shows that as well. Settings shows both.

If UDP cannot be chosen, direct receiver forwarding is not enabled at that time. You can still connect a receiver through the iPhone app, or write to [email protected] for help.

A station can have both ways in. Under Settings on the station's page, Add a token gives a UDP receiver a token as well, and Add a UDP address gives a token station a port; either can be removed again as long as one remains. Whichever way the reports arrive, they count for the same station, so moving from one to the other keeps its figures and its history.

Point the receiver at us

The page now shows a host, a port and the protocol, UDP. Enter them in the network output settings of whatever holds your receiver's data. Any receiver, plotter, multiplexer or program that can forward NMEA 0183 sentences to a network address will do, and most can:

• An AIS receiver, a transponder or an NMEA Wi-Fi gateway with a network connection usually has a UDP output or send to setting. Enter the host and the port there.
• In OpenCPN, add a network connection of type UDP with the host and port, and turn on output for it.
• An AIS dispatcher program, or a small computer running a receiver of its own, takes the host and port as a UDP destination.
• On a Signal K server, a plugin does the forwarding. Signal K below has the steps.

Send the AIS sentences as they come from the receiver. They begin with !AIVDM, and with !AIVDO for your own boat when the receiver is a transponder; she counts as a vessel like any other. If your GPS sentences travel on the same feed, they tell us where the receiver is listening from, and no other member sees that position. Anything else on the feed, depth or wind for instance, is ignored.

The host and port are not secret the way a password is. Open the receiver under My Stations at any time to read them again. If you want a different port, remove the receiver and add another; a replacement counts toward a plan from its first full month, as described under How to get Plus or Pro for free.

Signal K

Signal K runs on a Raspberry Pi, inside a Victron GX device and on other boat computers. It forwards AIS through a plugin, and two plugins do different jobs:

• ais-forwarder relays what your receiver hears to your station, unchanged.
• AIS Reporter sends AIS sentences describing your own boat, for a boat with a receiver but no transponder of her own.

Forward what your receiver hears

ais-forwarder is a relay: it does not decode or re-encode anything, so the sentences that reach us are the ones your receiver produced. It forwards AIS and nothing else, so there is nothing to trim on the Signal K side, and no GPS sentences travel with them.

1. Open your Signal K server's admin page and go to the app store.
2. Search for ais-forwarder, listed there as "AIS data (NMEA0183) forwarder", and install it.
3. Open Plugin Config and find AIS data (NMEA0183) forwarder.
4. Under UDP endpoints to send updates, use + to add one row, and set the fields below.
5. Save, then restart the Signal K server.

An endpoint saved with the two forwarding switches still off transmits nothing, and the station stays on Waiting for the first data.

Restart after every later change to these settings as well. Saving the configuration again without a restart leaves the previous forwarding running too, so the same sentence goes out more than once until the server restarts.

If your receiver is a transponder, its own-ship sentences travel with the rest and set where the station is listening from. If it is not, nothing in this feed carries a position, and you can set one by hand: Where the receiver listens from.

A receiver with no transponder can be reported as quiet on a still night. Because nothing but AIS travels, a receive-only station that hears nothing for an hour sends nothing at all, and that reads here as an outage. The tip above, about keeping GPS sentences on for exactly this reason, has no equivalent setting in this plugin. A transponder on the same feed keeps the station reporting through the quiet hours; where there is none, you can turn those notices off under Your stations in Notification settings.

AIS that arrives over NMEA 2000 does not reach the forwarder on its own, because the forwarder reads sentences from NMEA 0183 connections. Install signalk-n2kais-to-nmea0183, which converts that traffic, and set NMEA 0183 Events to nmea0183,nmea0183out so both are read. Names and other static data come through the converter as well as positions.

Suppress nmea0183 event, a setting on a Signal K NMEA 0183 connection, hides that connection's sentences from the forwarder. Leave it off on the connection carrying your AIS.

Report your own boat

AIS Reporter forwards nothing. On a timer it builds AIS sentences describing your own boat, from what Signal K knows about her, and sends them to the same kind of host and port. It needs no AIS transmitting hardware, so a boat with a receiver but no transponder can still put her own position on the network.

It needs an MMSI under Server > Settings > Vessel; without one it does not start, and says so.

1. In the app store, search for AIS Reporter (the package is @signalk/aisreporter) and install it.
2. Open Plugin Config and find Ais Reporter.
3. Under UDP endpoints to send updates, add a row with UDP endpoint IP address set to your station's host and Port to its port.
4. Save.

The rest are timings, and the defaults are fine:

Her name, callsign, ship type and dimensions go out beside the position, taken from Signal K's vessel settings, so what is filled in there is what she looks like on the map.

She is reported as another vessel rather than as own ship, so this does not tell us where your receiver is listening from. If no GPS sentences reach us from that receiver either, set the station's position by hand.

Your own software

Software you write or run yourself, on a Raspberry Pi or a boat computer for instance, can report what a receiver hears without an NMEA forwarder in between. Add the receiver with API token as its connection: the page then shows the token and the address to send reports to, and both stay on the station's page under Settings whenever you need them again. The software sends the token as a bearer token with every report. What a report contains, how often to send one and what comes back are on The station API. For a receiver aboard a boat that moves, the software also includes the receiver's position in every report, and sends a report that carries only the position when nothing is in range. The station API has the details.

If the token may have leaked, or you are replacing the software, choose New token on the station's page. The station keeps its name and its figures; the previous token stops working the moment the new one exists, so software still sending it is refused until it has the new one. A token station's row shows the start of its token, sls_ and eight characters, so you can tell two apart and match a row to the software that holds the token; that part is not secret, and it names the station in a message to support without sending the token.

Is it working?

Each station's row tells you:

• Live, with the number of vessels heard in the last 24 hours, once data has arrived within the last ten minutes.
• Last data and a time, when it has gone quiet.
• Waiting for the first data, when nothing has arrived yet.

The page updates while it is open, and the first data usually shows within about a minute of your receiver starting to send. If it stays waiting, check the host and port, that the output is UDP rather than TCP, and that the receiver is forwarding AIS sentences; for your own software, that reports go to the address shown and carry the token. Live with a vessel count of zero means data is arriving but no vessel positions have been counted. That can happen in quiet water or when the feed contains GPS data without AIS; check the receiver's own display or output if vessels are nearby.

See what it hears on the map

Once you run a station, the map gains a Local AIS button under Traffic. It opens what all your stations are hearing right now, together:

• A switch that draws those vessels on the chart, on by default.
• A row per station saying whether it is reporting, how many vessels it has in range and how far it has heard today.
• The vessels themselves, grouped by whether they are under way or stopped, each with its distance from your nearest station, with the ones heard earlier in the day below.
• Show all on the map frames the heard boats and your stations together.

Navigation aids and other transmitters your receiver hears are listed under what they are rather than drawn as boats.

On the chart, each station is drawn as a receiver mark with a dashed ring for how far it has reached today, and the vessels your stations hear are named a zoom or two before the rest of the traffic. Tap any of them and the panel says your station heard her and when. Turn Traffic off and only what your stations hear stays, beside your own boats, which is the quickest way to watch your home waters from a shore mast. The Types panel gains a small legend for these marks, and a type you hide there hides the boats you heard too.

Two limits to keep in mind:

• A vessel drops out of the layer when your stations have not heard her for a while, so a report from earlier in the day does not keep a boat shown as in range. She may still be on the chart as ordinary traffic, and the panel keeps her under "Heard earlier today".
• Your stations report in batches, so this view runs a little behind the receiver itself. On a phone that gap is longer for a boat sitting still, so a moored neighbour can leave "in range" while she is still there. The app aboard hears the receiver directly and does not have this gap.

When a station goes quiet

When a station that used to report has sent nothing for an hour, you get an e-mail, and a second one if it is still quiet after 24 hours; nothing more is sent until data resumes, when one all-clear goes out. The same notices appear under Notifications, and you choose whether you get them under Your stations in Notification settings.

A phone is not counted as quiet when the app is closed, a station you switch off is silent on purpose and gets no notice, and a station that has been silent since long before we first saw it gets no outage notice.

Where the receiver listens from

A receiver's position is set automatically when GPS sentences or its own transponder are on the feed, or when your own software includes the position in its reports. A shore receiver without GPS has none, and you can set one by hand on the website, under the gear on the station's page. The position draws the receiver, and how far it reaches, on your own map, and marks the receiver on the station's coverage area. No other member sees it, and the figures on its page do not need it.

Enter the position in decimal degrees, with N or S and E or W beside each number; a comma works as the decimal point, and a pair copied from a map app fills both fields when you paste it into either. When you are beside the receiver, Use my current position fills both in from the device you are using.

A position set by hand stays until you clear it, and the receiver's own reports do not change it. A position of 0°, 0°, which a GPS can report when it cannot determine its position, is treated as no position.

Switching off and removing

Switch a receiver off when it is out of use for a season and on again when it returns; its record stays, and the months it was off read as time not spent hearing and as days with no boats. Anything sent to its address, or with its token, is ignored while it is off. For the app's station, use Share with AIS Fleet on each iPhone.

Remove it and its coverage record, including its statistics, goes with it, though the vessels it already reported stay on the map. A station added again afterwards is a new one and can first earn a plan in its first full month, so switch a receiver off rather than removing it if you mean to bring it back. Closing your account removes every station you were running.