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ADCPtools

Beam to Earth coordinate transformations and other utilities for Acoustic Doppler Current Profiler (ADCP) data.

Convert profiles of along-beam velocity to Earth coordinates (east-north-up).

Convert raw along-beam velocity (positive toward transducer) time series (ntimes x nbins) to Earth-referenced velocity:

[u, v, w, w5] = janus5beam2earth(head, ptch, roll, theta, b1, b2, b3, b4, b5)

or, with all optional arguments specified,

[u, v, w, w5] = janus5beam2earth(head, ptch, roll, theta, b1, b2, b3, b4, b5, ...
                                 'uvwBeam5', true, 'Gimbaled', true, 'Binmap', 'linear', r, r5)

Where

  • b[1-5] are the along-beam velocity time series [ntimes x nbins] (positive toward transducer face).

  • u, v, w are the Earth-referenced (eastward, northward, upward) velocity time series [ntimes x nbins].

  • w5 is the vertical velocity calculated from the vertical beam only.

  • head, ptch and roll are the heading (rotation about the z-axis (beam 5), positive clockwise), pitch (rotation about the x-axis (beam 1), positive clockwise) and roll (rotation about the y-axis (beam 3), positive clockwise) angles measured by the ADCP, in degrees.

  • theta is the beam angle measured from beam 5's direction (vertical if the instrument is level), in degrees.

  • 'uvwBeam5' (true/false) indicates whether to use the vertical beam data to calculate u, v and w.

  • 'Gimbaled' (true/false) indicates whether the pitch and roll sensors were gimbaled (mounted on a free-swiveling platform as opposed to a rigid frame).

  • 'Binmap' ('none'/'nn'/'linear') indicates whether or not to perform bin-mapping on the raw beam velocities. Bin-mapping here means interpolating the velocities from all beams to the same horizontal plane before converting to instrument and then Earth coordinates. Defaults to 'none', i.e., the assumption that pitch and roll are zero at all times. 'linear' and 'nn' specify linear and nearest-neighbor interpolation, respectively.

  • r and r5 are vectors with the along-beam positions of the center of each bin for the Janus (#1-4) and vertical (#5) beams. Required only if 'Binmap' is not none.