4 - Navigation Chart Display

The navigation chart display is centered on the ROV. It displays a plan view of the ROV and the surrounding area. The ROV position is estimated by VideoRay CoPilot's navigation system - the accuracy of which depends on the frequency and quality of the absolute navigation fixes.

The viewer is always pointing to magnetic north; however the ROV icon will rotate in the center of the screen to reflect the current ROV heading.

When in AUTOFLY mode, the ROV is controlled in X (Surge) and Yaw (Heading) in the navigation chart display using the mouse. A left-button mouse click changes the current target position to the new screen coordinates where the click occurred. The target waypoint is represented by a cross and a trajectory line is drawn between the current ROV position and the target waypoint. A right-button mouse click changes heading. The target heading is displayed by a line of fixed length from the current ROV position at the requested target heading. The target heading is also displayed as a number at the end of the target heading line.

The number of turns the ROV makes over its own axis is displayed on the left side of the navigation chart display. A clockwise turn is represented by a positive number, and an anti-clockwise turn is represented by a negative number.

The navigation chart also displays a grid as a form of reference. The grid square scale is specified by the grid size label.

In addition to a grid, the navigation chart is also capable of displaying a user-defined water current velocity. The navigation chart display is also responsible for displaying the heads-up display messages indicating various system states.

4.1 Navigation Chart Display Zoom Scale Control

The navigation chart display zoom scale allows the user to change the displayed size of objects in the viewable area. The scale of the viewable area is measured from the center of view to the right or left edge of the viewable area. The scales are set to pre-defined values of 2m, 5m, 10m, 20m, 50m, 100m,200m and 500m (or their equivalent values in feet).