Long-range current profiling from moving vessels

Experiences over the last decade measuring upper-ocean current profiles from underway ships with acoustic Doppler current profilers (ADCPs) have demonstrated significant capabilities, but also identified serious limitations of existing ADCP systems. This paper describes recent advancements in shipboard ADCP technology that attempt to address these limitations such as range, accuracy, data robustness, reliability, and ease of use. New two dimensional phased array transducer technology, developed under the authors' sponsorship is combined with adaptable pulse-coherent "broadband" and pulse-incoherent "narrowband" digital signal processing within one unit. They describe these implementations and other improvements that deal with the limitations of current ADCPs, and predicted performance characteristics of 38, 75 and 150 kHz ADCP systems. Finally they present and discuss 38 and 150 kHz ADCP data collected in recent shipboard applications.