ATP-3-09-30 Observed Fires Download
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Target Location and Identification 28 September 2017 ATP 3-09.30 3-7 3-34. Each observer should calibrate ones hand and fingers to determine the width in mils for the various combinations of finger and hand positions shown, since finger and hand width vary for each observer. Calibrate hand measurements by comparing measurements taken with the hand and measurements taken with a more accurate measuring device. 3-35. When using hand and fingers in measuring angular deviation, the observer should fully extend the arm (elbow locked) so that the hand and fingers are always the same distance from the eyes. The observer always points the palm of the hand toward the target area and holds the fingers as demonstrated in figure 3-5 on page 3-7. Anything that changes the method, such as wearing a glove or not keeping the fingers together, will affect the measurement. 3-36. Hand measurement is a field expedient method for measuring angular deviation. Use methods that are more accurate than hand measurement when available. Figure 3-5. Example hand measurement of angular deviation Note. The observer should memorize the width (in mils) of the fingers their hand, in Figure 3-5 are examples, and will vary depending on the size of an individual’s hand. Then, when shifts of 100 mils or more are required, the observer can use the hand instead of binoculars for determining shifts to place fires on the adjusting point as quickly as possible. Using a Compass 3-37. Using a declinated M2 or a lensatic compass on a tripod or other stable platform, the observer can measure direction to an accuracy of 10 mils. Take care when using a compass around electronic devices such as radios and computers, or large concentrations of metal such as vehicles. Observers should move about 50 meters away from vehicles to avoid incorrect readings. Observers will always convert magnetic direction to grid direction for the CFF request unless otherwise stated. Scaling From a Map 3-38. Using a protractor, the observer can scale direction from a map to an accuracy of 10 mils. Observers may also use automated imagery to determine direction.