TAR 713 Land Navigation Techniques Flashcards
Dead Reckoning
The process of following an established azimuth for a specified distance
Dead Reckoning Steps
- Locate the starting point of each leg
- Use resection, intersection, and attack points
- On your map, determine azimuth from starting point to finish point, then convert the grid azimuth to a magnetic azimuth
- Determine the horizontal distance to that point on your map and convert it to a pace count
Resection
The method of locating one’s position on a map by determining the grid azimuth to at least two well defined locations that can be pinpointed
Resection: Map and Compass Steps
- Orient the map using the compass
- Identify two or three known distance locations on the ground and Mark them on the map
- Measure the magnetic azimuths
- Convert to grid azimuths
- Use a protractor to draw back azimuth lines
The intersection is your location
Magnetic Azimuth
The arc between the point on the horizon and the direction of magnetic north
Grid Azimuth
The angle between grid north and a line drawn on a map
True North
North according to earth’s axis, not magnetic north
GM Angle
The angular distance between grid north and magnetic north
- Expressed to nearest 1/2 degree
Declination
The difference between the three types of north
Magnetic North
North as determined by earth’s magnetic field
Grid North
North as determined on a flat map
- Parallel lines that do not converge
Convert Grid to Magnetic
- Add if westerly
- Subtract if easterly
- LARS (Left Add, Right Subtract)
Convert Magnetic to Grid
- Subtract if westerly
- Add if easterly
- RALS (Right Add Left Subtract)
LARS
Left Add, Right Subtract
Attack Point
An easily identifiable and recognizable feature on the map and on the ground
- Preferably 300m or less from your objective
Steering Mark
A well defined object on the ground in the direction of travel toward which the navigator must steer
Deliberate Offset
A process of intentionally offsetting to a particular direction when your objective is located on a linear feature
- One degree offset equals 17m for every 1,000m traveled
Number of MILS in Compass
6,400
RALS
Move right add, move left subtract
RALS Rule
- Used to bypass obstacles or enemy positions by detouring around them and still staying oriented to them by moving at right angles for specified distances
- At night, hold compass and turn until center of the E or W is under the luminous light
Collecting Features
- Features you plan to cross at any particular leg of a course
- Checkpoints to your objective
- Ideally 3+ per leg
- Check azimuths as you cross
Limiting/Stopping Feature
- A feature, preferably linear, beyond the objective
- Indicates you’ve traveled too far
Drift
The tendency to veer from the planned path
Factors that Affect Drift
- Terrain
- Obstacles
- Error in holding compass
- Compass error