Buoy Directional Wave Measurements Using Magnetic Field Components

Directional wave data can be estimated using the heave, pitch and roll motion of a discus buoy, which are conventionally measured by a pitch-roll sensor. To reduce the size and cost, this study presents a method to determine the buoy's azimuth, pitch, and roll angles from the two magnetic field components along two orthogonal axes parallel to the deck of a buoy measures by a fixed magnetometer. An evaluation of three months of directional wave measurements from a 3-meter discus buoy is presented. The directional wave data from using the magnetic agree well with those derived from measurements by a pitch-roll sensor.