ABSTRACT
There are five main categories of survey system that form the basis of traditional shallow profiling site survey tools. These are echosounders, sidescan sonars, pinger/ profilers, boomers, and multi-electrode sparkers. In addition there are a number of systems that combine two of these instruments in a single unit. Sidescan sonar and pinger combined units are one example of this. Each of these bottom and subbottom profilers is suited to different conditions and it is essential to know what survey information is required so that the optimum combination of equipment can be used. The different systems also have different weather capabilities and hence the time of year and area of operation will influence the choice of system. The type of shallow geology expected is also an important consideration which influences the optimum combination of systems. Technical developments in the 1990s included echosounder and sonar-based swath bathymetry. At the Millennium there was intense interest in autonomous underwater vehicles (AUVs) for deep water work.
