Position
This section describes the setup and operation of the positioning sensor — a critical component of the NSR ECDIS NES-3000 system that provides vessel coordinates from satellite navigation systems (GNSS).
Positioning Sensor Setup
Menu path |
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→ 
→ Sensors → Add sensor → PositionThe sensor connection and setup are performed in accordance with the procedure.
The source of coordinates can be the integrated navigation system **INS**.
ECDIS accounts for the GNSS antenna position relative to CCRP, therefore the GNSS antenna position in the ship’s coordinate system must be specified.
Ensure that received message processing is correctly configured in the sensor settings, i.e., processing of the corresponding headers and message types is enabled.
Some standard navigation data sentences may not include a checksum value in the transmitted data packet. A variant of incorrect checksum calculation by the GNSS (Global Navigation Satellite System) receiver is also possible.
To receive such data, ECDIS can verify or ignore the checksum (CRC — cyclic redundancy check) in incoming sentences.
CRC verification settings:
Verification disabled — all sentences will be considered valid
Verification enabled — only sentences that pass verification successfully will be processed
GNSS receivers work with multiple satellite navigation systems (SNS). Each SNS transmits data with a unique sentence header:
GN — Global navigation satellite system (GNSS);
GL — GLONASS positioning system;
GP — Global positioning system (GPS);
GA — Galileo positioning system;
GB — BeiDou positioning system;
GI — IRNSS positioning system;
GQ — QZSS positioning system;
SN — Electronic positioning system, other/general;
IN — Integrated navigation system.
Recommended Sentence Set for GNSS Receiver
Important
In ECDIS, it is possible to select sentences from any GNSS or from all simultaneously (see list above); to do this, configure the sentence filter by header. See section **Navigation Sensors (Sensors).**
Important
ECDIS system time is synchronized with UTC (Coordinated Universal Time) received from GNSS in the $--ZDA sentence each time ECDIS is started, and thereafter when the discrepancy between system time and received time exceeds 5 seconds.
If time synchronization data integrity is compromised, the current ECDIS computer system time is used in calculations until the time source is restored. The navigator cannot change the system time.
Positioning Sensor Operational Features
Positioning sensor data is recalculated by ECDIS taking into account the receiver offset relative to the vessel’s CCRP, and is displayed in the **Navigational Panel** and the **Log book**.
The vessel’s course vector is constructed from the positioning sensor data. For vector display settings, see the **Vectors and Trajectory** section. The course vector is constructed from the CCRP set in vessel dimensions.
If Differential receiver is enabled in the GNSS receiver settings, but the differential signal receiver is absent — ECDIS will generate a Differential signal lost warning (see table). The coordinate, COG, and SOG fields on the navigational panel will be highlighted in yellow.
No. |
Field |
Description |
|---|---|---|
1 |
Coordinates |
Coordinates received from the GNSS receiver. Coordinate system WGS 84. Received from sentences: |
POS |
Navigation parameter type — positioning |
|
GLONASS |
Name of the sensor providing the data |
|
Diff |
Sensor operating mode indicator |
|
2 |
Date/Time |
Ship date and ship time, adjusted for the time zone. Received from sentences: |
3 |
RMS |
Root mean square error of position determination. Received from sentence: |
Important
When switching to dead reckoning mode, it is recommended to calculate RMS and enter it manually after each manual observation
4 |
Course over ground |
Course over ground received from the GNSS receiver. Received from sentences: |
COG |
Navigation parameter name |
|
GLONASS |
Name of the sensor providing the data |
|
5 |
Speed over ground |
Speed over ground received from the GNSS receiver. Received from sentences: |
SOG |
Navigation parameter name |
|
GLONASS |
Name of the sensor providing the data |
Position Discrepancy
When two or more position sensors are connected to ECDIS, the discrepancy between the Primary and Secondary sensors will be calculated.
No. |
Element |
Description |
|---|---|---|
1 |
Primary position sensor with priority 0 |
|
2 |
Secondary position sensor with priority 1 |
|
3 |
Secondary position sensor coordinates |
|
4 |
Discrepancy |
Direction and distance between Primary and Secondary positions |
5 |
DR misclousure |
Display Secondary position on the ENC. Hide Secondary position — press again |
No. |
Element |
Description |
|---|---|---|
1 |
Primary position |
Based on data from Position sensor with priority 0 |
2 |
Secondary position |
Based on data from Position sensor with priority 1 |
Position Sensor Warnings
Text |
Category |
Condition |
|---|---|---|
Position (COG/SOG) error: <sensor name> |
Warning |
When data from the sensor stops being received according to the configurable timeout. |
HDOP exceeded: <sensor name> |
Caution |
When the HDOP (Horizontal Dilution of Precision) parameter value is greater than 4. Operates only when the GNSS receiver transmits |
No GNSS fix: <sensor name> |
Warning |
Mode indicator in the message has value N (No fix) for packets: |
Position lost: <sensor name> |
Alarm |
Positioning system mode indicator has value E in messages: |
Differential signal lost: <sensor name> |
Warning |
Positioning system mode indicator transitions from value D to any other value in messages: |
Differential corrections not applied: <sensor name> |
Warning |
Age of differential GPS data indicator. GNSS data staleness indicator in differential mode in |
GNSS data integrity violation: <sensor name> |
Warning |
If the sentence fails the CRC check. |
Coordinate discrepancy |
Warning |
If data from the |