c. One Observer Reporting Azimuth and Flash-to-Bang Time (Polar
To determine the location of GZ when only one designated observer has
reported an azimuth and flash-to-bang time, plot the observer's location
and reported azimuth. The flash-to-bang time must then be converted to a
distance to GZ using the appropriate nomogram.
Using the yield
estimation nomogram (Figure A-2, page 3 of the Supplemental Booklet),
locate the reported flash-to-bang time on the center scale. Reading on
the other side of the same scale, determine the distance to GZ. This
procedure is used in the company, battalion, and brigade headquarters to
plot ground zero (Figure 1-3).
EXAMPLE: Flash-to-bang time is 20
seconds, distance to ground zero is 7 km. The distance to GZ can also be
determined by multiplying the flash-to-bang time by 0.35.
EXAMPLE: 20 X 0.35 = 7 km,
After determining the distance to GZ, measure that distance on the
Graphic Scale (1000 meters per kilometer) and transfer it to the azimuth
line, measuring from the observer's locations.
One-Observer Azimuth and Flash-to-Bang Time
EXAMPLE: Observer A (coordinates 115225) reported a measured azimuth of a
nuclear cloud as 20 Grid. The same observer reported a flash-to bang
time of 20 seconds. After plotting the observer's location and azimuth,
the distance to GZ was determined to be 7 km. When plotted on a map, GZ
is determined to be at 138289.