Manual Observations

Manual Observations are designed for monitoring and refining the vessel position by visual or radar methods.

Menu path
→

Types of observations

The following types of observations are available:

• Position fixing by 2 or 3 bearings

• Position fixing by 2 or 3 distances

• Position fixing by bearing and distance to a single reference point

Important

When measuring navigational parameters, measure those parameters that change slowly first.

When measuring bearings:

• Measure bearings to reference points near the bow or stern bearings first

• Then those near the beam

When measuring distances:

• Measure distances to reference points near the beam first

• Then those near the bow or stern bearings

Important

When selecting reference points, choose those whose distance does not exceed 10 nautical miles. If the distance to any reference point exceeds 10 miles, the observation will not be calculated.

Performing an observation

1. Select the observation type

Tip

The observation method, reference points, and combination of reference points are selected by the navigating officer based on the current navigational situation.

Select the observation type from the dropdown list:

• Bearings — position fixing by 2 or 3 bearings

• Distances — position fixing by 2 or 3 distances

• Dist and bearing — position fixing by bearing and distance to a single reference point

The number of position lines is determined by the observed and positively identified reference points.

2. Select a reference point

Press Set ref. point, select a reference point on the chart.

The Objects under cursor table will display point objects on the chart located under the cursor, including the cursor position as a reference point.

Important

ECDIS scans objects located under the cursor. Object detection depends on the correct encoding of the ENC cell. When an object is detected and selected, the coordinates encoded in the object are used for calculations. If the navigating officer sets the cursor position as the reference point, the cursor coordinates are used for calculations. Higher priority should be given to chart objects.

3. Add an object to the reference points table

Select an object from the list and press the add button. The object will be added to the reference points table.

№	Element	Description
1	Reference point name (manual input)	Reference point name entered manually. During ENC encoding, some objects may be encoded without a name, or the object may not have a name (for example, a distinctive section of coastline)
2	Reference point name (automatic)	Reference point name populated automatically. Several objects or a composite object may be located under the cursor. In this case, the navigating officer must select the object independently
3	Sensor	The sensor from which measurements were taken. This may be a standard optical pelorus on the port or starboard side, or a radar. The sensor selection is taken into account when calculating the observed position coordinates
4	Measurement time	The time of the navigational parameter measurement. All measurements are reduced to the time of the last measurement
5	Navigational parameter	The value of the measured navigational parameter (bearing or distance)
6	Delete position line	Delete the navigational parameter. The navigating officer may delete a navigational parameter depending on the situation. Deletion of a navigational parameter is available only before solving the task
7	Positioning on reference point	Pan the chart to the selected reference point
8	Master mode	Black font labels — ECDIS in Master mode, observation can be accepted for dead reckoning
9	BackUp mode	Gray font labels — ECDIS in BackUp mode, only manual position fixing is available, but the observed position cannot be accepted for dead reckoning

Tip

Always add reference point names for subsequent analysis of observations.

Warning

To prevent navigational blunders, the **Pelorus** sensor or the **Radar** sensor must be configured.

4. Calculate the observed position

Press Calculate to calculate the observed position.

The observation will be plotted on the chart, and the results will be displayed in the Results window: observed coordinates and position discrepancy.

№	Element	Description
1	Position lines	Graphical display of position lines on the chart
2	Vessel track line	Display of the vessel track line up to the moment of observation
3	Vessel position by primary position source	Vessel position by the primary position source at the time of the manual observation (time of the last measurement)
4	Position from manual observation	Position obtained from the manual observation, indicating the method used
5	Observed position coordinates	Observed coordinates
6	Position discrepancy	Discrepancy from the position by the primary position source to the observed position

5. Accept the observation for dead reckoning

To accept the observation for dead reckoning, press Apply.

Confirm the selection in the dialog.

The vessel position will be shifted to the observed coordinates. ECDIS will switch to dead reckoning mode.

№	Element	Description
1	Manual observation accepted for dead reckoning	Display of the observed position accepted for dead reckoning
2	Track line segment	Track line segment along which the vessel was proceeding before accepting the observation for dead reckoning
3	Vessel position transfer	Transfer of the vessel position to the track line calculated from the observed position accepted for dead reckoning
4	Current dead reckoning position	Current dead reckoning position of the vessel after accepting the observation

Viewing observations in the navigational log

The observation result is automatically recorded in the navigational log.

Viewing the navigational log:

→ → Manual Observation

To view an observation in detail, double-click the selected record row.

Returning to GNSS position correction

To return to GNSS position correction, perform the following steps:

Menu path
→ → DR/Manual Input → Dead Reckoning → Off

Important

When fixing the vessel position by astronomical methods, the observed coordinates are entered in the **Manual Input and Correction** section, or the position can be plotted using **Mariner’s Objects**.