AIS Operational Features
Attention
To display AIS targets on ENC — enable the AIS layer.
Enable |
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Menu path |
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No. |
Element |
Description |
|---|---|---|
1 |
Show AIS group |
AIS target display settings |
2 |
Guard zone group |
Guard zone settings |
3 |
Lost targets group |
Lost target monitoring settings |

No. |
Element |
Description |
|---|---|---|
1 |
Show AIS |
Enable AIS layer |
2 |
Show ARPA targets |
Enable ARPA layer |
3 |
ARPA and AIS association |
Enable ARPA and AIS target association |
4 |
Show associated targets as AIS |
Display associated targets as AIS targets |
5 |
Always show real AtoN purpose |
Always display real AtoN |

No. |
Element |
Description |
|---|---|---|
1 |
Guard zone |
Enable guard zone. |
2 |
Show guard zone |
Enable guard zone display. Targets entering the guard zone are assigned the status Dangerous target |
3 |
Guard zone radius |
Guard zone radius |
4 |
Lost zone |
Enable lost target control zone. Within the zone, alerts will be generated for lost AIS targets, ARPA targets, and synthetic targets |
5 |
Lost zone radius |
Lost target control zone radius |

No. |
Element |
Description |
|---|---|---|
1 |
Lost AtoN alert |
Generate alarm on AtoN loss |
2 |
Lost SART alert |
Generate alarm on SART loss |
3 |
Lost AtoN/SART distance |
AtoN and SART loss tracking distance. Beyond the set radius, ECDIS will not generate an alarm for AtoN and SART loss |
AIS display settings, processing criteria, and filtering
Menu path |
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No. |
Element |
Description |
|---|---|---|
1 |
AIS activation group |
AIS target activation and filtering settings group |
2 |
AIS Filtration group |
AIS target display type settings group |
3 |
ASM group |
ASM display settings group |

No. |
Element |
Description |
|---|---|---|
1 |
Auto activation |
Enables auto-activation of AIS targets |
2 |
Show auto activation range |
Display auto-activation radius (red color) |
3 |
Auto activation range circle |
Radius within which AIS targets are activated |
4 |
Max capacity AIS targets |
Maximum number of displayed AIS targets |
5 |
Max capacity AIS synth targets |
Maximum number of displayed synthetic AIS targets |
6 |
Max capacity ASM |
Maximum number of displayed ASM |

No. |
Element |
Description |
|---|---|---|
1 |
Filtration |
Sets all AIS targets to sleeping status |
2 |
Visibility by range |
Area radius within which AIS targets are displayed on the chart |
3 |
Visibility range |
AIS target visibility distance on the chart |
4 |
Show sleeping targets |
Enables display of sleeping targets within the visibility range with the specified filtering parameters: Class A, Class B, CPA, TCPA. The set filtering parameters will be displayed in the permanent indication area |
5 |
Show activated targets |
Enables display of activated targets |
6 |
Class A |
Enables/disables display of Class A sleeping targets |
7 |
Class B |
Enables/disables display of Class B sleeping targets |
8 |
AIS Base stations |
Enables/disables display of AIS base stations |
9 |
Real AtoN |
Enables/disables display of Aids to Navigation with AIS |
10 |
Virtual AtoN |
Enables/disables display of virtual Aids to Navigation with AIS |
11 |
SART |
Enables/disables display of AIS SART distress signals |
12 |
SAR Aircraft |
Enables/disables display of aircraft (helicopter) involved in search and rescue operations |
13 |
Synthetic target |
Enables/disables synthetic targets transmitted by a base station or as ASM |

No. |
Element |
Description |
|---|---|---|
1 |
Show ASM |
Enable display of AIS application specific messages |
2 |
Tidal window |
Tidal data: high water, low water, current tidal phase |
3 |
Water level |
Current sea level value |
4 |
Current |
Current surface current value |
5 |
Wind |
Current wind value, average wind and gust forecast |
6 |
Weather |
Current weather data for the specified period |
7 |
Sea State |
Sea state (wave conditions) |
8 |
Air Grap |
Current air gap height under an overhead crossing or bridge |
9 |
Area Notice |
Areas subject to warnings, alerts, and special information |
10 |
Berthing data |
Availability of port services at berths |
11 |
Routing |
Routes transmitted by addressed message (main, alternate, ice) |
12 |
Signal Station |
Current port dispatcher signal, the next signal, and its activation time |
Note
ASM are transmitted as both broadcast and addressed messages. The navigator manages the reception of addressed ASM independently. ECDIS only displays received messages.
After enabling the AIS layer display, all AIS targets, synthetic targets, and ASM within the AIS target visibility radius will be displayed on the chart.
Important
ECDIS supports displaying a limited number of targets. To avoid overloading the ECDIS computer, limits on displayed targets on the ENC must be set:
Max capacity AIS targets – no more targets than specified are displayed. AIS target filtering is performed by distance. When a new target appears, the most distant non-dangerous target is removed from display.
Max capacity AIS synth targets – no more synthetic targets than specified are displayed. Synthetic target filtering is performed by distance. When a new synthetic target appears, the most distant non-dangerous synthetic target is removed from display.
Max capacity ASM – no more ASM than specified are displayed. ASM filtering is performed by distance. When a new ASM appears, the most distant ASM is removed from display.
Load management is performed only within the set visibility radius.

No. |
Element |
Description |
|---|---|---|
1 |
Own ship |
Own ship symbol on the chart |
2 |
Sleeping target |
Non-activated AIS target within the visibility zone |
3 |
Guard zone |
Circle defining the target control area |
4 |
Dangerous target |
Target requiring the navigator’s attention |
5 |
Name of dangerous target |
Text label of the dangerous target on the chart |
6 |
Auto-activation zone |
Circle upon entering which targets are automatically activated |
7 |
Activated target |
Target under tracking with detailed information displayed |
8 |
Tracked target symbol |
Visual marker of the target selected for tracking and target data in the multifunction window |
9 |
Name |
Name of the tracked target |
10 |
Closest Point of Approach (CPA) to target |
Minimum distance at which the target will approach own ship |
11 |
Time to Closest Point of Approach (TCPA) to target |
Time to closest point of approach |
12 |
Course Over Ground (COG) of target |
Course Over Ground — direction of target movement over the Earth’s surface |
13 |
Speed Over Ground (SOG) of target |
Speed Over Ground — speed of target movement relative to the Earth’s surface |
14 |
Heading (HDG) of target |
Heading — compass heading, if transmitted |
15 |
Rate of Turn (ROT) of target |
Rate of Turn — rate of heading change, if transmitted |
16 |
Targets Table |
Opens the targets table |
17 |
Details |
Opens the extended target form |
18 |
Bearing (BRG) to target |
Bearing — Bearing to the target from own ship |
19 |
Distance (DIST) to target |
Distance — Distance to the target from own ship |
20 |
Target Coordinates |
Geographic coordinates of the target |
21 |
POS ACC |
AIS target position accuracy |
22 |
RAIM |
Navigation data integrity monitoring indicator in the AIS target |
23 |
Messages |
Opens the incoming messages table. When new messages are received from the target, a new incoming message symbol will be displayed to the right of the button |
24 |
Target MMSI |
Maritime Mobile Service Identity — unique vessel identifier |
25 |
Target call sign |
Vessel radio call sign |
26 |
Status — Navigation status of target |
Current navigation status of the vessel (under sail, at anchor, etc.) |
AIS targets are displayed in accordance with the configured filtration and activation settings. The coordinates, vectors, and trajectories of AIS targets are displayed on the ENC based on the data from their last received message, in accordance with ECDIS settings.
Depending on the AIS target type, the content of the target form may differ:
AIS target form transmitted by ARPA

Search and rescue aircraft AIS target form
Target Activation and Deactivation
Forced tracking of a target outside the auto-activation radius is performed manually.
In automatic mode, activation occurs if the target enters the auto-activation radius or becomes dangerous. Upon leaving the auto-activation radius or when the dangerous status is removed, the target is deactivated.
To forcibly activate a target — hover the cursor over the target, right-click (press and hold) to open the context menu, select Activate. The target will be placed under tracking.

To forcibly deactivate targets — hover the cursor over the target, right-click (press and hold) to open the context menu, select Deactivate. The target will be deactivated.

Target Information
Target information is displayed in the AIS window. To obtain target information — left-click (tap) on the target of interest.
The target will be highlighted with a frame. The information on the selected target will be displayed in the AIS window.

CPA/TCPA
Target monitoring by closest point of approach and time to closest point of approach.
Menu path |
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No. |
Element |
Description |
|---|---|---|
1 |
Don’t calculate CPA/TCPA |
Disables CPA/TCPA calculation in ECDIS |
2 |
CPA/TCPA alarm |
Enables target monitoring |
3 |
Closest point of approach |
Sets the closest point of approach distance |
4 |
Time to closest point of approach |
Sets the time to closest point of approach |
After enabling CPA/TCPA monitoring, all targets within the visibility zone will be monitored by CPA/TCPA. When the CPA/TCPA value is below the set threshold, targets will be automatically activated, marked as dangerous, and ECDIS will generate an appropriate alarm.
Lost Targets
When Lost target alert is enabled, targets from which no data is received within the specified timeout will be marked as lost. Lost targets are removed from the chart, and a lost target warning is generated.

Warnings are generated only for active targets.
If data stops being received from a dangerous target, the target will be marked as lost but will remain on the chart. ECDIS will generate a lost target warning. When the warning is acknowledged, the target will be removed from the chart.
Own Ship AIS
ECDIS can display data from the own ship AIS.
Menu path |
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No. |
Element |
Description |
|---|---|---|
1 |
AIS transmits |
Data transmitted by the AIS sensor over the air |
2 |
System data |
Current data set in ECDIS settings, to be sent to AIS |
3 |
Send data to AIS device — forced transmission |
of own ship data to AIS |
Data Transmission to AIS Transponder
Vessel data can be transmitted to AIS from ECDIS.
Data modification is performed in Registration data.
Data transmission is performed automatically with a 5-minute interval. If necessary, data can be sent forcibly:
Menu path |
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Data is transmitted in VSD and SSD sentences, which include the following information:
Cargo category (message 5)
Navigation status (messages 1, 2, 3)
Draught (maximum actual static, message 5)
Port of destination (message 5)
Estimated date and time (UTC) of arrival (message 5)
Number of persons on board the vessel (message 5)