ATP-3-09-30 Observed Fires Download
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Adjustment of Fire 28 September 2017 ATP 3-09.30 5-25 5-84. The objective of the time portion of the precision registration is to correct the mean HOB of four rounds fired with the same data to 20 meters above the registration point. If the first round is a graze burst, a correction of UP 40 is given. Once the observer achieves a measurable airburst, the command is 3 ROUNDS REPEAT. After firing four rounds with the same data, end the registration with the appropriate correction to achieve a 20 meter HOB. 5-85. When four airbursts are spotted, correct the HOB to 20 meters. Determine the mean HOB by adding the four spottings (in mils), dividing by 4, expressing the sum to the nearest mil, and then multiplying by the observer-target factor. (This is the same technique used in determining deviation corrections.) The sum is then expressed to the nearest 5 meters and the appropriate correction is determined to achieve the desired 20 meter HOB; for example, UP 10, RECORD AS TIME REGISTRATION POINT, END OF MISSION, OVER. 5-86. When three airbursts and one graze burst are spotted, the HOB is correct. No correction is required. 5-87. With two airbursts and two graze bursts, the HOB correction sent is UP 10. 5-88. With one airburst and three graze bursts, the HOB correction sent is UP 20. 5-89. It is a good idea to fire check rounds to verify the validity of the time registration; however, it is not mandatory. If the first airburst is extremely high, the observer may make a down correction and fire one round. If that round is at a measurable HOB, the observer can then fire the additional three rounds. Quick and time registration examples are (figures 5-15 through 5-17 on pages 5-24 through 5-27):