What the sonar technician actually sees is a rather odd-looking display called a waterfall. It looks like a green television screen full of snow or 'noise.' The top of the display shows the bearing of a particular noise source or frequency being detected. The vertical scale shows that noise or frequency over time. The sonar technician is looking for something that stands out from the random pattern of background noise being displayed. Usually the sound contact appears as a solid line on the display screen. And this is where the hunt begins.
The technician reports the contact to the sonar watch supervisor and begins the process of classification and identification. The supervisor alerts the officer of the deck that a new sonar contact, called 'Sierra Ten,' for example (contacts are numbered progressively), has been detected and that the sonar team is working it. The conventions for naming contacts are:* Sierra-a sonar contact* Victor-a visual contact* Romeo-a radar contact* Mike-a contact combining one or more signals from different sensors
What is important now is patience and concentration. And much like my character Jonesy, these technicians pursue just as much an art as a science. As soon as the first sound line has established that a contact exists, the other technicians assist in the classification. Despite all that has been written before, there is no automatic classification mode in the boat's computers-one of the
Sometimes a frequency line is known to be unique to a particular power plant of a particular ship or submarine class. Other times, the effort to classify the target may require the technician to listen through headphones to try and make out what the signal on a particular bearing is. They can listen to tonal signals to determine whether the source is a surface ship or submarine. Each of the different sonars in the BSY-1 suite has its optimum frequency band, and if another sensor might be better at getting data on a particular signal, the technician is fully empowered to ask the officer of the deck to alter course to bring that sensor to bear. During this time the sonar watch team are the eyes and ears of the boat, and every other man aboard knows that his safety may depend on just how good the operators in the sonar room really are. There are set procedures to help guide the sonar technicians, but in the end it comes down to the individual skills of the technicians doing what must be a mind-bending job.
The sonar supervisor reports the best estimate of what and where the source is, and whether it could be a threat or not, to the officer of the deck (OOD). The OOD stations the fire control team to begin the localization/tracking process. This is a dual process utilizing both the manual plotting table as well as one of the fire control consoles. On
This takes time-sometimes, a lot. While you are trying to get all the information necessary to possibly shoot at a target, you must yourself remain undetected. Much of the data for the TMA process comes from the bearing rate, which is how fast the bearing of a target is changing, and monitoring the Doppler, which reveals whether a target is coming nearer or moving away; this is called the range rate. While the BSY-1 is helping the fire control team do its job, the manual plot team, assisted by a specially programmed Hewlett Packard 9020 desktop computer, is also working on its own TMA/range analysis. This little desktop computer has a program library that helps the manual plot team with the more intensive calculations and generates what can only be called instant ranges to the target. All the while the manual and automatic tracking solutions are checked, and data is crossfed between them. During the TMA process the boat would probably maneuver in a zigzag pattern to help the sonar crew establish better range and bearing rates for the TMA plots.
Some nations have chosen to eliminate the dual TMA process and depend only on an automatic system. But this can lead to ranging errors in critical situations, so the U.S. Navy continues to use manual plots and automatic systems just to be sure. Recently
The TMA process is continued until the commanding officer believes the tracking party has a good enough picture of the situation at hand. Every contact has to have a reliable TMA solution and must be currently tracked. Here lies the real value of the BSY-1 system. For while the earlier Los Angeles-class boats could keep track of only a few targets at one time, the BSY-1 can handle many more. And once the system has a good track running, it has a great ability to hold and maintain the quality of the tracks.
Eventually the target track(s) will be good enough to fire on, if that is the desired intention, and the time has come to set up a weapon for firing. The fire control technician begins the process by inputting the necessary presets into the chosen weapon. If it is a Mark 48, Harpoon, or Tomahawk antiship missile (TASM), this can be accomplished entirely at the BSY-1 console. Should a Tomahawk land attack missile (TLAM) need to be programmed, this is accomplished at the adjoining Command and Control System (CCS-2) console. For now, though, we will concentrate on the weapons programmed on the BSY-1 console.
If, for example, the desire is to launch an antiship missile, the technician must have a decent estimate of target course, speed, and range. It is also critical to know whether there is any neutral shipping traffic in the area. The technician programs in the route to the target, as well as any waypoints necessary to route the missile around neutral shipping traffic that might be in the way. In addition, the technician programs a search pattern for the seeker head of the missile to lock in. This mission plan can be loaded into any number of missiles, which are then fired from the weapons control console located to the right of the fire control consoles.
The process for firing torpedoes is somewhat more dynamic than that for missiles. First the fire control technician develops a fire control solution through a process called 'stacking the dots.' The screen where this is accomplished displays the target bearing versus time, similar to that back in the sonar room. On this display the target bearing is shown over a period of time as a series of dots. The technician fine-tunes the solution by adjusting the estimates of the target's range, course, and speed until the display shows a straight column of dots stacked on
