Recent development in Doppler sonar technology

There has been significant recent progress in the development of Doppler sonar systems for marine research. Major advances include the development of side-scan Doppler systems for surface wave, ship wake and Langmuir cell research, the development of coded pulses for improved sonar precision, and the development of phased array Doppler sonar for 3D (x, y, t,) imaging of flow fields. Perhaps surprisingly, the Arctic has emerged as a prominent testing ground for many of these new technologies. The combination of a stable platform (the sea-ice) and extremely low natural signal levels enables accurate quantification of system performance. In the first section of this work the authors outline an approach to pulse coding which they have been exploring, with the objective of improving sonar precision. The second section reviews experience gained in the 1989 Coordinated Eastern Arctic Experiment, CEAREX and the 1992 Beaufort Sea Experiment, LEADEX. A brief discussion of a new phased array system the authors are developing for three dimensional observations concludes the work