INS

Connection, setup, and operational features of INS as a data sensor

Purpose

INS receives data from various navigation sensors (GNSS, gyrocompass, log, echo sounder), performs processing, majority voting, evaluates data reliability, generates or relays navigation data, and performs simple dead reckoning and dead reckoning with total drift compensation.

The Integrated Navigation System (INS) is the source of the following data:

• vessel coordinates

• vessel heading

• vessel speed

• speed generation mode

• course over ground

• speed over ground

• depth

• time

When configuring sensors: Position, Heading, Speed, Depth, the connection to INS must be configured in accordance with ship documentation.

INS transmits a special sentence $INNSR (Integrated Navigation System Status Report), which contains:

• Data integrity information (Integrity) — reliability indicator for each navigation parameter

• Data quality indicator (Quality indicator) — assessment of data quality from the source

• Speed generation mode (Speed mode) — method of determining vessel speed (Auto, Estimated, Manual)

Note

The $INNSR sentence must be received by ECDIS for correct operation of the data quality monitoring system.

ECDIS, receiving data from INS, generates warnings and cautions about the status of data received from INS. Additionally, data statuses are displayed in the **Navigational Panel**.

INS Setup

The sensor connection and setup are performed in accordance with the procedure.

Depending on the architecture, INS may transmit data to a single port or to multiple ports to prevent communication channel overload.

Important

During sensor configuration, note that sensor coordinates are specified relative to CCRP (Center of Common Reference Point). If the ship documentation specifies coordinates relative to CCRS (Center of Common Reference System), coordinate recalculation is required. For more information on configuring sensor coordinates.

When creating sensors receiving data from INS, the following minimum set of NMEA sentences must be configured for reception. This is a mandatory requirement for correct ECDIS operation:

• Position:

  • $--GLL

  • $--DTM

  • $--VTG

  • $--ZDA

• Heading:

  • $--THS

• Speed:

  • $--VBW

  • $--VDR

• Depth:

  • $--DPT

All sensors connected to INS must receive the $INNSR sentence.

Hint

When the $INNSR sentence is selected, the user-defined sentence selection is automatically disabled, and the recommended sentence set is enabled as specified above.

Note

The navigator, based on console review, may enable reception of additional sentences from INS for the configured sensor type at their discretion.

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.