[GrayOwl]

Sonalysts Game Design Notes:
The passive sonar modeling in Sub Command was modified from 688I in an
effort to upgrade the sonar detection and classification performance. Sub
Command models the individual variables in the passive sonar equation:

Passive Sonar Signal Excess = Radiated Noise - Propagation Loss - Interfering Noise - Recognition Differential


1. Radiated Noise is the initial source level of the signal that emanates
from the contact. Broadband radiated noise varies with speed, narrowband
radiated noise does not.

2. Propagation Loss is the amount of loss the source signal sustains as it
travels from the contact to the sonar. Sub Command calculates proploss on
the fly, accounting for the loss due to interaction of the signal with the
acoustic boundaries (surface, bottom, and thermal layer) and the
attenuation loss of the signal as a function of range.

3. Interfering Noise is a combination of background noise (sea state, rain,
shipping density) and self noise (noise emanating from the detecting ship)
that is a function of own ship speed..

4. Recognition Differential is how well a sonar system can differentiate a
signal from the background noise. Sub Command models separate sonar
Recognition Differentials depending on sonar type and model.

All these variables are modeled in Sub Command to determine whether or not
to display a signal on a sonar screen, and how brightly to display the signal.

Broadband radiated noise varies by platform class, and is adjusted for
target speed. Broadband radiated noise values are modeled for
representative frequencies in the 2 kHZ - 4kHZ range. ???!!!

Narrowband radiated noise is modeled by assigning a narrowband profile to each
appropriate platform - 5 discrete narrowband frequencies. The 5 discrete narrowband
lines range in frequency from 50 Hz - to - 2 kHZ. All U.S. built ships
will have a 60 HZ lines because the U.S. uses 60 cycle electrical
equipment. The rest of the world uses 50 cycle electrical equipment, so
their narrowband profile will have a 50 HZ line.

Low frequency signals propagate through water with much less loss than do
high frequency signals. Therefore, in most cases the best/initial
detection sensor will be the detection of narrowband lines on the towed
array. The window at the top of the Narrowband Station allows the user to
perform a narrowband search. Even though a signal is not visually apparent
in the search window, moving the cursor through all the bearings may
discover a narrowband contact line that will then be displayed in the
middle window. This occurs because the sonar system is able to pull a
signal out of the noise. This is the systems Recognition
Differential. This is the reason why an auto Sonarman will report a
contact that the player does not visually see on the Broadband screen.

The lower frequency lines will be detected first as the range between ships
closes, and the brightness of the lines will depend on the calculated
Signal Excess. The Broadband Station will generally detect after detection
has been made on the Narrowband Station. Towed arrayed broadband will
detect first over the spherical and cylindrical arrays because of it's
lower frequency band and better recognition differential. However,
spherical and cylindrical array detections eliminate the problem with the
ambiguous towed array detection.

The environmental inputs for each mission have a major effect on the sonar
detection performance. The inputs are environmental profile type (surface
duct, convergence zone, bottom limited), bottom type (rock, mud, sand), and
sea state (0-5). The depth of the water is also a major factor. These
inputs are available in the mission editor.===========================


All that is written above - complete false.
That that is declared, obviously does not work. To deceive very bad...


Damn It and more damn it!