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071-329-1030 (SL1) - Navigate from One Point on the Ground to Another Point While Mounted

Standards: Directed the driver to the designated point(s) at a rate of nine kilometers per hour using terrain association and dead reckoning.

Conditions: Given a standard 1:50,000-scale topographic map of the area, a coordinate scale, a protractor, and a compass, while mounted in a vehicle with cross-country capability and tasked to move from a known start point to one or more distant points.

Note: See appendix C for related skills and knowledge supporting performance of this task.

Standards: Directed the driver to the designated point(s) at a rate of nine kilometers per hour using terrain association and dead reckoning.

Performance Steps

1.   Determine the effects of terrain on the vehicle when navigating mounted.

a. Vehicle speed and mobility.

(1)  Great distances may be covered quickly. Develop the ability to estimate the distance traveled. Meanwhile, use the odometer, which shows the distance traveled. Remember that .1 mile is roughly 160 meters, and 1 mile is about 1,600 meters or 1.6 kilometers.

(2)  Mobility is an advantage while navigating. When disoriented, mobility makes it easier to move and reorient.

b. Vehicle capabilities.

(1)  Most military vehicles can knock down a tree. Larger vehicles can clear more trees but cannot knock down several trees at once. Find paths between trees that are wide enough for the vehicle (figure 071-329-1030-1).

Figure 071-329-1030-1. Vehicle capabilities


CAUTION: During training, follow installation SOP or local guidelines concerning cross-country vehicle travel

(2)  Military vehicles are designed to climb 60-percent (30-degree) slopes if the surface is dry and firm. If gravel, vegetation, or mud is on the slope, the practical slope-climbing capability is about 40 percent (20 degrees) (figure 071-329-1030-2).

Figure 071-329-1030-2. Climbing slope and side slope capabilities


(a)   Determine the approximate slope by looking at the route selected on a map. One contour line in any 100 meters of map distance on that route indicates a 10-percent slope. Two contour lines indicate a 20-percent slope, and so forth. If there are four contour lines in 100 meters, look for another route.

Note. The above figures are true for a 10-meter or 20-foot contour interval. If the map has a different contour interval, adjust the arithmetic. For instance, if there is one contour line in 100 meters, a 10-meter interval would give a 10-percent slope.

(b)   The side slope is more important than the climbing slope. A 40-percent side slope is the maximum in good weather (figure 071-329-1030-2). Traverse a side slope slowly and without turning. Rocks, stumps, or sharp turns can cause a downhill track to be thrown under the vehicle, which is a major recovery task.

(3)  For tactical reasons, movement is often in draws or valleys due to the cover they provide. Side slopes make slow movement necessary.

2.   Know the effects of weather on vehicle movement.

a. Weather can halt mounted movement. Snow and ice are dangerous. Rain and snow affect soil load-bearing ability. Heavy rain may restrict cross-country vehicles to road movement.

b. Adjust the route to avoid flooded or muddy areas. A stuck vehicle hinders combat capability.

3.   Know both methods of navigation.

a. Terrain association. This is the most used method of navigation. The navigator plans the route for movement from one terrain feature to another. An automobile driver uses the same technique while driving along the streets in a city. He guides himself using intersections or other landmarks. Like a driver, the navigator selects routes, or "streets," between key points, or "intersections." These routes must sustain vehicle travel, and should be as direct and easy to follow as possible. In a typical move, the navigator determines his location and the location of his objective. He notes the position of each on his map and selects a route between the two.

(1)  Determine the start point and destination.

(2)  Draw or visualize a straight line between the two points on the map.

(3)  Inspect the terrain along that line for ease of movement, for features recognizable under predicted weather conditions, and for tactical considerations.

(4)  After analyzing the terrain, adjust the route by doing the following:

(a)   Consider tactical aspects. Avoid skylining, select key terrain for overwatch positions, and select concealed routes.

(b)   Consider ease of movement. Use the easiest possible route. Bypass difficult terrain. A difficult route is hard to follow, noisier, causes more wear to the vehicle (and possibly recovery problems), and takes more time. Tactical surprise is achieved by doing the unexpected. Try to select an axis or corridor and not a specific route. Allow room for vehicles to maneuver.

(c)   Use terrain features as checkpoints. Checkpoints must be easily recognizable, from a moving vehicle, under the current light and weather conditions. The best checkpoints are linear features that cross the route. Use perennial streams, rivers, hardtop roads, ridges, valleys, and railroads. The next best are elevation changes; hills, depressions, spurs, and draws. Look for two contour lines of change. Less than two lines of change cannot be spotted while mounted.

(d)   Follow terrain features. Movement and navigation along a valley floor or near or on the crest of a ridgeline are easiest.

(e)   Determine directions. Break the route into smaller segments and determine the rough direction that will be followed. The compass is not needed; use the main points of direction (north, northeast, east, for example). Before moving, note the location of the sun and the direction of north. Locate changes of direction, if any, at the checkpoints chosen.

(f)    Determine distance. Obtain the total distance to be traveled and the approximate distance between checkpoints. Plan to use the vehicle odometer to keep track of distance traveled.

Note. Convert map distance to ground distance by adding 20 percent for cross-country movement.

(g)   Make notes. Usually, mental notes are adequate. Imagine what the route will be like and remember it.

(h)   Plan. Restudy the route selected. Determine where problems may occur and how they may be avoided.

b. Dead reckoning. Dead reckoning means moving a set distance along a set line. It involves moving so many meters along a set line, usually an azimuth in degrees.

Note. There is no accurate method of determining direction in vehicles.

(1)  Dead reckoning with steering marks. This procedure is the same as it is for on foot travel.

(a)   Dismount from the vehicle.

(b)   Move away from the vehicle (about 50 meters).

(c)   Set the azimuth on the compass and choose a steering mark (rock, tree, hilltop) in the distance on that azimuth.

(d)   Remount and have the driver identify the steering mark. Proceed to it in as straight a line as possible.

(e)   On arrival at the steering mark or when direction is changed, repeat paragraphs (a) through (c) for the next leg of travel.

(2)  Dead reckoning without steering marks. Use this only in flat, featureless terrain.

(a)   Dismount from the vehicle, which has been positioned in the direction of travel. Move about 50 meters to the front of the vehicle.

(b)   Face the vehicle and read the azimuth to the vehicle.

(c)   By adding or subtracting 180 degrees, determine the forward azimuth (direction of travel).

(d)   Have the driver drive on a straight line toward you.

(e)   Remount the vehicle, hold the compass as it will be held while the vehicle is moving, and read the azimuth to the front.

(f)    The compass swings off the azimuth determined, but it should pick up a constant deviation. For instance, the azimuth to the steering mark was 75 degrees while you were away from the vehicle. When you remounted, and the driver drove straight forward, the compass showed 67 degrees. There is a deviation of minus 8 degrees. All that is needed is to hold the 67-degree heading.

(g)   At night, do the same thing without a steering mark. From the map, determine the azimuth of travel. Line the vehicle up on that azimuth, then move well in front of the vehicle. Be sure it is aligned correctly. Mount, have the driver move slowly forward, and note the deviation.

Note. If the vehicle has a turret, traversing the turret changes the deviation.

(3)  Turret alignment. If the vehicle has a stabilized turret, another method is alignment of the turret on the azimuth to be traveled. Switch the turret stabilization system ON. The gun tube remains pointed at the destination no matter which way the vehicle is turned.

CAUTION: If you have to take the turret off-line to engage a target, repeat the entire process

Note. This technique works, and it is not harmful to the stabilization system. However, the vehicle is subject to stabilization drift; therefore, use this technique for no more than 5,000 meters before resetting.

(4)  Distance factor. Computing the distance factor in dead reckoning is usually a simple process. Determine the map distance to travel and add 20 percent to convert to ground distance. Use the vehicle odometer to control the distance of travel.

4.   Learn to combine and use both methods.

a. Terrain association is fast and error-tolerant. It is the best method under most circumstances, and it can be used day or night.

b. Dead reckoning is accurate if done correctly-precision is a requirement. Dead reckoning is slow, but works in flat terrain.

c. Often, dead reckoning and terrain association are combined. Use dead reckoning to travel across a large, flat area to a ridge. Use terrain association for the rest of the move.

d. The ability to use both methods is required. Probable errors, in order of frequency, are as follows:

(1)  Failure to determine distance(s) to be traveled.

(2)  Failure to travel the proper distance.

(3)  Failure to properly plot or locate the objective.

(4)  Failure to select easily recognizable checkpoints or landmarks.

(5)  Failure to consider the ease of movement factor.

Evaluation Preparation: 

Setup: At the test site, provide the materials and equipment given in the task conditions. Select an area that has varying terrain and vegetation. The area must be large enough to have three to five points that are 1,000 meters to 5,000 meters apart. Each point is on or near an identifiable terrain feature and is marked on the ground with a sign containing a letter or number. Place dummy signs not less than 100 meters or more than 200 meters to the right and left of the correct point. Clearly mark all correct points on the map. Prepare a sheet of paper giving the azimuth and distance for each leg of the course. Have pencils available for the soldier.

Brief Soldier:

1. Terrain association. Give the soldier the map and tell him to direct the driver and vehicle over the course recorded on the map. Tell the soldier to record the letter or number at the end of each leg of the course. Tell the soldier the course will be covered using terrain association.

2. Dead reckoning with steering marks. Give the soldier a protractor, a compass, and a sheet of paper with the azimuth and distance for each leg of the course. Maps are not used. Tell the soldier to direct the driver and vehicle over the course recorded on the paper. Tell the soldier to record the letter or number at the end of each leg to the course. Tell him the course will be covered using steering marks.

Performance Measures



1.   Terrain association. Wrote the correct letter or number found at the end of each leg of the course.



2.   Dead reckoning.



a. Moved away from the vehicle.



b. Set azimuth on compass and selected steering mark.



c. Had the driver identify the steering mark.



d. Wrote the correct letter or number found at the end of each leg of the course.



e. Repeated steps in performance measure 2a, b, and c for each leg of the course.



Evaluation Guidance:  Score the soldier GO if all performance measures are passed. Score the soldier NO GO if any performance measure is failed. If the soldier fails any performance measure, show what was done wrong and how to do it correctly.







FM 3-25.26



FM 90-3