## INS Messages

Depending on the manufacturer, protocol version implementation, or for other reasons, INS may not support or perform data integrity and reliability assessment.


### INS Warnings (for all data types)

| Text | Category | Condition |
|-------|-----------|---------|
| Sensor malfunction \<INS\> | Alarm | When data from the sensor stops being received according to the configurable timeout |
| Heading unreliable | Warning | Displayed in the alarm, warning, and caution area |
| Integrity of \<parameter name\> violated | Warning | Displayed in the alarm, warning, and caution area |
| Integrity of \<parameter name\> doubtful | Warning | Displayed in the alarm, warning, and caution area |
| \<parameter name\> unreliable | Warning | Displayed in the alarm, warning, and caution area |

```{important}
The navigator's response to INS warnings is determined by prevailing conditions and circumstances.
```

Additionally, the vessel speed generation mode is transmitted in the ``$INNSR`` sentence, which is displayed in the STW row of the **Navigational Panel**:

- **Normal operating mode** (Auto) — speed is determined based on direct measurements from the water-referenced speed sensor. The speed value is displayed without additional markings
- **Estimated mode** (**Estimated**) — speed is calculated without direct water-referenced measurements (e.g., via GNSS or inertial navigation). The system automatically marks such data to inform the navigator
- **Manual input** (**Manual**) — speed is entered manually from the INS control panel. Used when speed sensors fail or under special navigation conditions

```{note}
When operating in **Estimated** or **Manual** mode, it is recommended to regularly verify speed readings with alternative sources to ensure data accuracy.
```
