Vessel motions are movements in the vertical and horizontal frames that are typically induced by wind, waves, turning and accelerating.

Boreas can provide position at four different points on a ship for heave, surge and sway respectively. The Boreas vessel motion filter is always on and fully automatic. After power on, Boreas requires approximately 5 minutes for its vessel motion filter to converge upon an accurate solution. Vessel motion works without a GNSS fix, however the best performance is achieved when Boreas has a GNSS fix from an external GNSS receiver.

By default Boreas provides heave, surge and sway from the point at which the Boreas unit is mounted, however it can provide vessel motion data at four different offset points on the ship. To configure Vessel Motion, see the Configuration Menu page in the web UI or use the Reference Position Offsets dialogue in the Boreas Manager.

Surge

Surge is the longitudinal (front-to-back) motion. Surge is outputted as a momentary position of the vehicle/vessel referenced to the mean position (the mean of the surge over a long period of time is always zero). Surge is measured positively forward along the X axis.

Sway

Sway is the transverse (side-to-side) motion. Surge is outputted as a momentary position of the vehicle/vessel referenced to the mean position (the mean of the sway over a long period of time is always zero). Sway is measured positively right along the Y axis.

Heave

Heave is the vertical (up/down) motion. Heave is outputted as a momentary position of the vehicle/vessel referenced to the mean position (the mean of the heave over a long period of time is always zero). Heave is measured positively down along the Z axis.