In the mid 1970s, acoustic Doppler techniques were first applied to the internal wave measurement problem. Since then, both pulse‐to‐pulse coherent (short‐range) and incoherent (long‐range) sonars have been developed. Recently, a 161‐kHz device that can operate in either mode, as well as a hybrid coded mode, has been created. In the hybrid mode, broadband pulses are transmitted. Doppler shift is estimated from the phase progression within individual returns. Incoherent averaging from pulse to pulse further improves the precision of the velocity estimate. Velocity error variance is reduced by a factor of 10 relative to uncoded pulses. The hybrid sonar was first operated in the Arctic, north of Svalbard, in conjunction with the 1989 ONR experiment, Cearex. While the under ice boundary layer was examined using a fully coherent operating mode, the large‐scale internal wave field was sampled to depths of 500 m using the hybrid transmission scheme. Strong baroclinic subinertial motions were seen at diurnal tidal frequency. These occasionally became unstable, producing borelike events with amplitudes in excess of 50 m. Toward the end of the experiment, an eddy drifted under the ice camp. The precision of the sonar was sufficient to resolve a “crown” of internal waves trapped to the dome of the eddy.