COG bounce/ erratic

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Tom,

It is recommended that you verify that only one source of GPS data has been interfaced to the system. If so, then please note that some GPS sensors, including early Raymarine GPS sensors, will report COG when the vessel is stationary. By definition, a stationary vessel has no COG. Raymarine's latest generations of GPS sensors (i.e. Raystar 150 and Raystar 130) offered significant improvements in filtering to not produce COG for stationary vessels.
Should the movement of the Chart application's screen in response to COG not be desirable, when stationary or maneuvering, then it would be recommended that the Chart application page/pane being viewed be configured to North Up chart orientation and to have the vessel icon centered on the screen rather than be offset. Once underway and making way, the Chart application may be reconfigured to Head Up and any offset then applied.