SonTek RS5 User Manual (August 2020) 144
Appendix E. Matlab Export File Structure
IMPORTANT NOTES:
• The term “sample” refers to a single vertical profile, taken over a period of 1 s.
• For the four parameters containing Velocity data (BottomTrack.BT_Vel, Summary.Mean_Vel,
Summary.Boat_Vel, and WaterTrack.Velocity), the data are in the same coordinate system that
was selected in the software when the .mat file was exported.
For example:
BT_Vel when exported in ENU coordinates will be:
1. East Velocity (i.e. velocity to the East)
2. North Velocity
3. Up Velocity
4. Difference Velocity (aka Error Velocity; the difference between measuring the vertical com-
ponent of the velocity from the two pairs of opposing beams)
BT_Vel when exported in XYZ coordinates will be:
1. X Velocity
2. Y Velocity
3. Up Velocity
4. Difference Velocity
BT_Vel when exported in Beam coordinates will be:
1. Beam 1
2. Beam 2
3. Beam 3
4. Beam 4
• GPS Altitude (from the GGA string) is based on a proprietary, non-published geoid, and
referenced to the bottom-center of the antenna.
The basic order of the root structures is as follows. For the Size Column:
• NS is the number of samples;
• NC is the maximum number of cells;
• If the structure contains another structure inside it, or the parameter is a scalar, the size is NA.
Bottom Track Velocity, Depth and Frequency
variables (includes Vertical Beam)
General parameters pertaining to various
settings
GPS data and quality information.
The raw GPS data from either the internal GPS
or an external serially connected GPS system.
This data is stored in its raw format with the
same frequency that was output from the GPS
System settings, edge information and profile
extrapolation