Finland AIS Vessel Tracker

Source{{ resultSourceLabel }} Motion{{ selectedMotionLabel }} Position{{ selectedPositionLabel }}

Vessel identifier or name:

Blank retrieves the newest capped snapshot; a value narrows it before local filters run.

Match field:

The resolved match field is recorded in the audit and exports.

Vessel type:

Any is neutral; a type selection narrows both the provider query and canonical result.

Moving vessels only:

Turn this option on when moving vessels only is required.

Result cap:

vessels

Reference latitude:

Use decimal degrees from -90 to 90.

Reference longitude:

Use decimal degrees from -180 to 180.

Radius:

#	Vessel	Identity	Type	Motion	Voyage / position	Select	Copy
{{ row.rank }}	{{ row.name }}	{{ row.identity }}	{{ row.ship_type }}	{{ row.speed }} {{ row.heading }}	{{ row.destination }} {{ row.position }}

Check	Status	Evidence	Next action	Copy
{{ row.check }}	{{ row.status }}	{{ row.evidence }}	{{ row.next_action }}

The chart renderer is unavailable. Speed-band values remain available in the downloadable CSV.

Open OSM Open Google

The map renderer is unavailable. Coordinates and external map links remain available.

Automatic Identification System (AIS) messages let vessels broadcast identity, position, motion, and selected voyage information over maritime radio. Shore receivers collect those reports into traffic snapshots. The result is useful for finding a contact or reviewing nearby movement, but it is not a continuous radar picture and it is not cleared navigation guidance.

Different fields answer different questions. A Maritime Mobile Service Identity (MMSI) identifies the radio station and normally has nine digits. An IMO number identifies many regulated ships across changes of name or flag, while a callsign and vessel name are easier to recognize but less reliable for unique matching. Confirm more than one identity field when the distinction matters.

Position is a reported latitude and longitude with source and accuracy indicators that may be absent or stale.
Speed over ground and course over ground describe motion relative to Earth, not engine setting or where the bow points.
Heading describes the vessel's reported bow direction; course is used as a fallback when heading is unavailable.
Navigation status, destination, and estimated arrival are reported fields and can be outdated or entered incorrectly.

A nearby-contact search adds another approximation. Great-circle distance measures the shortest surface path between the reference coordinates and each reported position. It does not follow a channel, account for land, or describe safe passing distance. A vessel just inside a radius can also move outside it immediately after the snapshot.

Conflicting fields are a reason to refresh and cross-check. A vessel may report positive speed while its navigation status still says moored or at anchor, and a matching name can belong to more than one contact. Operational decisions require an appropriate navigation, port, or vessel-information source rather than a single public AIS record.

How to Use This Tool:

Choose between an identity lookup and a bounded traffic snapshot before adding filters.

Enter an MMSI, IMO number, callsign, or vessel name in Vessel identifier or name. Leave it blank to request the newest capped snapshot.
Keep Match field on auto for a nine-digit MMSI, seven-digit IMO number, or name search. Choose callsign or name explicitly when the text could be misclassified.
Open Advanced to restrict vessel type, require positive reported speed, or set a result cap. For a nearby search, provide both reference coordinates and then an optional radius.
Run the lookup and select the intended row. Compare Vessel snapshot with Signal audit; use the speed distribution and map as supporting context after identity and freshness checks.

Interpreting Results:

Start with MMSI, IMO number, callsign, and name. A partial identity match is weaker than agreement across several fields, and a name-containing search may return several vessels.

A mappable position means coordinates were returned, not that the report is current enough for navigation.
A speed/status mismatch is flagged when speed exceeds 0.5 knots while navigation status says at anchor, moored, or aground. Refresh before deciding which field is stale.
Destination and estimated arrival are self-reported voyage claims. Treat blanks and implausible values as missing evidence rather than proof of no destination.
When a reference point is supplied, rows with coordinates are ordered by calculated distance. Without one, rows are ordered by vessel name and then MMSI.

Technical Details:

A lookup requests a bounded set of records from a public Finnish AIS feature layer. Identifier, vessel-type, and moving-only conditions narrow the provider request. Records are then normalized, optionally measured against a reference point, filtered by radius, sorted, and capped for the displayed snapshot.

Lookup Core

AIS search resolution and filtering rules
Choice	Governing rule
Auto match	Exactly 9 digits resolves to MMSI; exactly 7 digits resolves to IMO; other nonblank text resolves to vessel name; blank requests the snapshot.
Explicit callsign or name	Case-insensitive contains match.
Moving vessels only	Keep records with reported speed over ground greater than 0 knots; zero and missing speed are excluded.
Vessel type	Use the reported AIS ship-type code groups, including passenger 60–69, cargo 70–79, and tanker 80–89.
Reference position	Latitude must be from −90 to 90 degrees and longitude from −180 to 180 degrees; both are required together.
Radius and cap	Keep distance ≤ the positive radius, up to 20,000 km, then return the first 1 to 200 rows.

Formula Core

Speed over ground is displayed in knots and converted to kilometres per hour with the exact factor 1.852.

v_{km/h} = v_{kn} \times 1.852

Radius filtering uses the haversine formula with a mean Earth radius of 6,371 km. Latitudes and longitudes are converted from degrees to radians before the calculation.

d = 2 R asin (\sqrt{\sin^{2} (\frac{φ_{2} - φ_{1}}{2}) + \cos (φ_{1}) \cos (φ_{2}) \sin^{2} (\frac{λ_{2} - λ_{1}}{2})})

Here, R is 6,371 km, φ is latitude in radians, and λ is longitude in radians. Distance is displayed to one decimal place; latitude and longitude are displayed to four decimal places, while copied coordinates use six decimal places.

Rule Core

The speed profile counts the retained rows after identity, type, moving-only, radius, ordering, and result-cap rules have run.

AIS speed band boundaries
Band	Reported speed over ground
Stationary	Exactly 0 kn
Harbour	> 0 and ≤ 5 kn
Coastal	> 5 and ≤ 12 kn
Underway	> 12 and ≤ 20 kn
Fast	> 20 kn
No speed	No numeric speed was returned

Heading and course values are normalized into 0 to less than 360 degrees. Reported heading is preferred; course over ground is substituted only when heading is missing. The nearest of eight compass labels is then selected for display.

Accuracy and Privacy Notes:

AIS is public traffic data, but the query still leaves the browser. The search term, match type, vessel-type filter, moving-only choice, and result cap are sent to the public data service. Reference coordinates and radius are used for local distance filtering after records return.

Reports can be delayed, absent, duplicated, or inconsistent. Position accuracy flags do not make a stale report current.
The position map loads third-party map tiles, and opening an external map sends the selected coordinates to that map provider.
Do not put private operational notes into the search field or a shareable page address.
Use authority-approved navigation and port systems for collision avoidance, clearance, or other safety-critical work.

References:

Marine traffic and AIS data fields, Digitraffic by Fintraffic.
Recommendation ITU-R M.1371: Technical characteristics for the automatic identification system, International Telecommunication Union.