The forward observer (FO), as the "eyes" of the indirect-fire team, has the primary mission of locating suitable targets and calling for and adjusting fire on these targets. He also has the mission of collecting intelligence information that can be derived from surveillance of his area of responsibility y. Such information is reported through charnels to higher headquarters.

To accomplish his primary mission, the FO must select an observation post (OP) from which he can obtain maximum observation of his area of responsibility and still have the necessary cover and concealment. (It is also desirable for the approach to the OP to have more than one covered and concealed route, so the FO cannot be observed by the enemy as he moves in or out of this OP.)

The forward observer, working as part of the indirect-fire team, functions as an effective part of the team if he understands and applies the procedures and techniques discussed below.

Target-Grid Method of Adjustment

Using the target-grid method of adjustment, anyone with a means of communication to an infantry or artillery fire direction center and who can read an azimuth can adjust fire on the targets he can see. From the forward observer's viewpoint, this method is much simpler than previous methods because he does not have to know the location of the guns and he does not have to compute as much data. It makes no difference how far he is off the gun-target line because the fire direction center (FDC) makes adjustments to keep the burst on the observer-target line. To place fire on the target, the forward observer follows three simple steps:

1. He establishes communication with the FDC.

2. He attempts to locate the target for the FDC.

3. If the initial round or rounds miss the target, he sends corrections to the FDC that will cause subsequent rounds to hit the target.

A trained FO or a communications expert is not necessary to observe and adjust fire for mortars; however, it helps to know communication procedures and the method of conducting fire as explained in this chapter.

The target-grid method of adjustment has the following advantages:

1. The FO enjoys freedom of movement on the battlefield since he is not concerned with the location of the mortar and the mortar-target line. This enables him to accompany the unit he is supporting, thereby giving it close and continuous fire support.

2. One forward observer can mass the fires of all mortar and artillery units within supporting range on a given target.

3. The combat Seabee can fill any gaps in the forward observer's field of view, thus giving better indirect fire support to infantry units.

4. It simplifies the work of the forward observer and places the burden of computing on personnel at the FDC who usually work under better conditions.

5. It eliminates the necessity of training a large number of forward observers to compute correction factors and requires only relatively few trained computers at the FDC.

6. The system does not depend entirely on the accuracy of the forward observer's azimuth to the target.

Errors as great as 100 mils can be made without having any appreciable effect on the adjustment. Larger errors throw the burst off the observer-target (OT) line; however, such errors are easily detected by the computer, and the correct azimuth can be quickly determined by connecting two on-line bursts on the plotting board and reading the azimuth of this line.