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OCR for page 3
As identified by Navy speakers, new major systems under development include
fixed distributive systems, tactical and surveillance multi-scale low frequency active
sonars, new ASW patrol procedures, automated detection systems, and tactical
environmental forecasting (TESS).
· -—
· . —
Research examining the effect of the environment on acoustic signals has
particularly emphasized:
.
Sub-bottom propagation of very low frequency energy,
· Bohom, surface, and volume reverberation at 50-1 00 Hz,
· Matched-field processing, and accompanying descriptions of transmission
characteristics,
· Mesoscale environmental predictive models and accompanying acoustic
models,
· Tomography, a potential validation too! for the models and a technique for
determining propagation characteristics over large areas, and
· Fast acoustic performance prediction models.
The naval officers were optimistic about their improved detection ability,
particularly their ability to cletect new signal types. They emphasized that young,
inexperienced operators must be able to use tactical oceanographic systems in a
complex and confusing environment. Tactical oceanography products must be in
summary form and readily accessible (through personal computers or simple graphs)
to a busy non-scientist.
ACADEMIC-NAVY COOPERATION
Navy laboratory and academic representatives spoke at length about the
extensive shore-based environmental measurement and prediction systems and about
large-scale oceanographic experiments. These experiments are important in
producing the data for Navy operations as well as for defining system characteristics.
Although symposium participants were reminded that there was more to the
Navy than ASW, and more to ASW than acoustics, virtually all the talks reflected the
importance of ASW in Navy operations. Many speakers reiterated that the changed
Soviet threat has prompted greater interaction between acoustic and oceanographic
research communities than there has been for two to three decades, but this
collaboration could still be improved. Ocean physical and acoustic characteristics are
3
OCR for page 4
now reasonably connected in major moclels. However, it is still necessary to
encourage connections between acoustics and ocean biology, marine geology and
geophysics, coastal sciences, and marine meteorology.
When the significance of Soviet quieting was finally recognized,
oceanographers played a major role in setting new courses of action. The High Gain
Initiative, for example, was initially intended to define the limits on passive detection
through oceanographic studies. It was based on the hypothesis that at sufficiently low
frequencies, acoustic signals are scrambled by multi-path interference caused by
measurable or predictable mesoscale features, rather than by the unpredictable
internal wave field. Thus, the possibility of "unscrambling" the signal using
combinations of models and observations could be tested in a rational experimental
program. The continuing emphasis on acoustics is coupled with a need for a better
understanding of non-acoustic ocean parameters. Basically, ASW is a form of applied
oceanography; an operator or decision maker knowledgeable about ocean
characteristics and processes is better equipped to do his or her job.
lt was noted that, although 'tactical oceanography" signifies immediately
available decision aids, there are other significant immediate impacts of oceanographic
research upon Navy operations and decisions. Although the Soviets do not operate
with better knowledge of fronts and eddies than do U.S. forces at the present time,
our need to maintain a permanent invulnerability of our submarine nuclear force
requires that we maintain a scientific advantage in this field of study. The only
reasonable approach to resolving such problems is to develop a detailed
understanding of ocean characteristics and processes.
Both ASW and seagoing oceanographic research are based on extracting
information from the ocean. The tools used by naval and scientific practitioners have
common characteristics: for example, robustness, deployability, and covertness to
avoid disruption. Both kinds of practitioners need to deploy instruments in remote
areas, leave them in place for long periods of time, and relay data back to shore. As
resources become more limited, it will become increasingly important to examine
cooperation and sharing of platforms, instrumentation, and data between naval and
academic scientists. Prime examples of the operational Navy sharing with academic
researchers are the ONR large ship building program, FLIP, the GEOSAT altimetry
satellite, the ARGO/Medea remotely operated vehicle system, the large scale computer
at Bay St. Louis, acoustic sources for the Heard Island Experiment, and use of the
Integrated Undersea Surveillance System (lUSS) network to track SOFAR floats and
receive acoustic signals for ocean tomography experiments.
4
Representative terms from entire chapter:
acoustic signals
