ATP-3-09-30 Observed Fires Download
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Adjustment of Fire 28 September 2017 ATP 3-09.30 5-43 Figure 5-25. Determining the intercept point Example (See figure 5-21.) The distance measured between points A and B is 50 meters. The time interval between A and B is 10 seconds. Speed of the target is 50 meters in 10 Seconds, or 5 meters per second. Total processing time is 3 minutes (180 seconds). Time of flight is 20 seconds. The distance at which to plot the intercept point is 5 meters per second X 200 seconds, or 1,000 meters. The observer must convert minutes to seconds for this procedure to work. 5-130. Given the above example, the intercept point must be at least 1,000 meters in front of the target along the intended path of the target. The method of control should be observer control (at my command). Then use the intercept point grid in the call for fire as the target location. DETERMINE THE TRIGGER POINT 5-131. After determining the intercept point and sending the mission to the firing unit, the observer must determine a point at which to command the guns to fire. This point is determined to ensure both the rounds and the target arrive at the intercept point at the same time. When the target passes over or near the trigger point, the observer commands the guns to fire. 5-132. In determining the trigger point, the observer must consider the intended path of the target, target speed, time of flight, and call for fire transmission time. 5-133. The first step is to determine the distance from the planned target location or intercept point to the trigger point. The observer adds the transmission time (an average of 5 seconds) to the time of flight received in the MTO and multiplies this sum by the speed of the target.