Development projects in the parts of the Navy responsible for research with a more applied focus, the so-called 6.2 and 6.3 sectors of Navy research, could benefit from more frequent interaction with the academic oceanic electromagnetic community, whose experience is primarily in research with longer term application. The reverse is certainly true as well, and academic electromagnetism specialists would be better able to help Navy meet its needs if they were more aware of the Navy's requirements.
As interest in electromagnetic surveillance increases and more effort is expended on development of prototype systems, it is clear that a considerable base of knowledge on the electromagnetic environment in shallow water is absent. At the present time, no published data from water shallower than 1,500 meters appear in the open literature. The reason, in large part, is that the Office of Naval Research terminated its electromagnetics efforts about five years ago; thus there is no clear avenue for investigators to fund the necessary exploratory basic research. Although considerable information about the electromagnetic environment in deeper water is available, including identification of sources and understanding of interactions with the seafloor, the understanding is not immediately applicable to shallow water. What is needed is a focused program of basic research to understand the two primary sources, external (ionospheric and magnetospheric) and hydrodynamic types, along with their interactions with the continental shelf. It is not sufficient just to make a few measurements and extrapolate them because the shallow-water oceanographic and geological environment is highly variable and difficult to predict (a priori). Instead, it is important that the origins of the fields be understood; what is required is a multidisciplinary scientific approach that clearly lies in the basic research area. In the absence of basic information on and understanding of the noise environment, it is difficult to devise proper noise cancellation hardware and software, and the obvious tendency will be toward “overdesigning” surveillance systems, resulting in higher than necessary costs and possibly poor performance. It is in the Navy's interests to address the basic research issues in a timely fashion.
Further development of electromagnetic sensor technology for undersea use is clearly not a primary issue at present. All the available sensors (both electric and magnetic) are limited by environmental noise, and the major goals should be a better understanding of that noise so that it can be canceled effectively. Further,