User Guide

Point C where the lines of bearing cross indicates the maximum range for lead course contact A
and a minimum range for lag course contact B.
As you can see in the drawing, you cannot initially be sure whether you are leading or lagging a
contact.You can determine this after you turn your ship to a course on the opposite side of the line
of bearing.
By changing your ship’s contribution to the bearing rate you can mathematically reduce the
number of possible solutions for the available data.You do this by changing the course and/or
speed of your submarine.The more you change your ship’s contribution to the bearing rate, the
more dramatic the change in the data. In most cases the leg with the larger bearing rate indicates
a lag course. For a broadband contact, this may be easier to see on the sonar waterfall display.
If the contact maintains its course and speed and the sonar bearings are very accurate (they may
not be for weak contacts), two or three Ownship maneuvers, or legs, will result in a single possible
solution if the maneuver produces a moderate change in bearing rate.
Use all available information when creating your trial solutions. If an intel message informs you the
contact is on a specific course or traveling at a specific speed, enter those values in the trial
solution fields. Knowing a second value, such as speed, eliminates a large number of possible
target solutions. Once a contact is classified, determine its speed using the DEMON function in
Sonar.
THE TMA BOARD
The TMA board is located in the upper left area of the TMA Station.The board displays a
representation of Ownship, a history of bearing data for a selected contact, a TMA ruler and an
T+10
T+8
T+6
T+4
T+2
T
T+12
T+14
T+16
SINGLE
SOLUTION
T+10
T+8
T+6
T+4
T+2
T
POSSIBLE SOLUTIONS
A
C
B
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