Heading Sensor Operational Features

The vessel heading is displayed in the following interface elements:

Navigational Panel
Off-scale Danger Indicators (Danger Course Indicator)
Log book in the Standard Position (Track) section

Navigation Panel

No.	Field	Description
1	Heading	Heading received from the heading sensor. Received from sentences: `$--HDG`, `$--HDT`, `$--THS`
	HDG	Navigation parameter name — heading
	Gyro_Prim	Name of the sensor providing the data
2	Rate of Turn	Rate of turn received from the heading sensor, if the sensor generates it. Received from sentences: `$--ROT`
	ROT	Navigation parameter name
	Gyro_Prim	Name of the sensor providing the data
3	–	Visual representation of heading on the heading scale of the off-scale danger indicator. Received from sentences: `$--HDG`, `$--HDT`, `$--THS`

Heading Discrepancy

When two or more heading sensors are connected to ECDIS, the discrepancy between the Primary and Secondary sensors will be calculated.

Misclousure POS

No.	Element	Description
1		Primary heading sensor with priority 0
2		Secondary heading sensor with priority 1
3	Discrepancy	Heading discrepancy between Primary and Secondary heading sensors

Important

When heading sensor data is absent, the vessel mark on the chart is displayed without heading line indication, and the vessel outline will not be displayed at ENC scale.

When heading data is available, the following tasks are performed:

total drift compensation;
wind calculation;
vessel movement with drift calculation and monitoring band construction;
anchor watch;
vessel outline construction at chart scale;
radar image overlay.

Heading Sensor Warnings

Operating mode messages (rows 2-5 of the table) are generated based on the Mode indicator field value in the THS message.

TEXT	CATEGORY	CONDITION
Heading sensor error: <sensor name>	Warning	When data from the sensor stops being received according to the configurable timeout.
Simulation mode: <sensor name>	Warning	Mode indicator field has value S — simulation mode.
Dead reckoning mode: <sensor name>	Warning	Mode indicator field has value E — dead reckoning mode.
Manual heading input: <sensor name>	Warning	Mode indicator field has value M — manual input.
Heading sensor data invalid: <sensor name>	Warning	Mode indicator field has value V — data unreliable.
Magnetic variation unknown: <sensor name>	Warning	Unable to obtain or calculate true heading. The HDG message is used for calculations and heading display in the system, but magnetic variation data is absent.