## AIS Operational Features

```{attention}
To display AIS targets on ENC — enable the AIS layer.
```
| Enable |
|-------------|
| {{ btn_quick_settings }} → {{ ais_layer }} AIS Layer |
| Menu path |
| {{ menu }} → {{ settings }} → Targets → Settings |

![Description](images/Targets_Settings_1.png)

| 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 |

![Description](images/Targets_Settings_2.png)

| 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 |

![Description](images/Targets_Settings_3.png)

| 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 |

![Description](images/Targets_Settings_4.png)

| 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 |
|-------------|
| {{ menu }} → {{ settings }} → AIS → Filtration and activation |

![Description](images/AIS_Filtration_1.png)

| 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 |

![Description](images/AIS_Filtration_2.png)

| 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 |

![Description](images/AIS_Filtration_3.png)

| 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 |

![Description](images/AIS_Filtration_4.png)

| No. | Element | Description |
|---|---------|----------|
| **1** | **Show ASM** | Enable display of AIS {doc}`application specific messages </sections/sensors/ais/asm/index>` |
| **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.
```

![Description](images/AIS_2.png)

| 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.<br><br>

Depending on the AIS target type, the content of the target form may differ:

AIS target form transmitted by ARPA
![AIS form from ARPA](images/Radar_Target_1.1.png)

Search and rescue aircraft AIS target form
![SAR aircraft form](images/AIS_2.2.png)
<br><br>
#### 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.

![Description](images/image445.png) ![Description](images/image446.png)

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.

![Description](images/image447.png) ![Description](images/image448.png)<br><br>

#### 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.

![Description](images/AIS_2.3.png)<br><br>

#### CPA/TCPA

Target monitoring by closest point of approach and time to closest point of approach.
| Menu path |
|-------------|
| {{ menu }} → {{ settings }} → Targets → CPA/TCPA |

![Description](images/CPA_TCPA_1.png)

| 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.<br><br>

#### 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.

![Description](images/image452.png)

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.<br><br>

#### Own Ship AIS

ECDIS can display data from the own ship AIS.
| Menu path |
|-------------|
| {{ menu }} → {{ settings }} → Targets → AIS → Own ship |

![Description](images/image453.png)

| 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 |
<br><br>

#### Data Transmission to AIS Transponder

Vessel data can be transmitted to AIS from ECDIS.

Data modification is performed in **{doc}`Registration data </sections/vessel-settings/vessel-registration-data/index>`**.

Data transmission is performed automatically with a 5-minute interval. If necessary, data can be sent forcibly:
| Menu path |
|-------------|
| {{ menu }} → {{ settings }} → Targets → AIS → Own ship → Send data to AIS device |

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)
