RDI narrowband 153kHz ADCP

Each beam of the ADCP transmits an acoustic pulse and then measures the Doppler shift in the backscattered acoustic energy as a function of time.

The acoustic signal is scattered back toward the transducer by particles and plankton in the water that are assumed to be moving, on the average, with the ocean currents.

The time-gated frequency shift is then used to compute a beam-direction velocity component as a function of range (or distance from the transducer) for each beam.

Using compass measurements, the range-gated beam velocities are then converted into vertical profiles of zonal (east/west), meridional (north/south), and vertical velocities.