text: Appendix B
  COMMON REFERENCE SYSTEMS
  B-6. Airspace element personnel work with several references systems such as military grid, latitude and
  longitude, area grid reference systems, and several altitude reference systems. For planning and immediate
  execution, these common reference systems require simple, widely distributed, and integrated platforms and
  weapons systems. Common reference systems are also a means to “digitize” operational environments and
  provide a two-dimensional construct from which three-dimensional control and coordination measures can
  be constructed at the operational level.
  POINT REFERENCE SYSTEMS
  B-7. Airspace element personnel use the World Geodetic System 1984, Military Grid Reference System,
  and geographic coordinates as point reference systems.
  World Geodetic System 1984
  B-8. The World Geodetic System 1984 (WGS 84) is the official Department of Defense positional reference
  system. The earth is an ellipsoid, not a sphere. It’s flattened slightly at the poles and bulging somewhat at the
  equator. Datums are reference surfaces that consider the curvature of the earth for the mathematical creation
  of geodetic and cartographic data. Numerous datum exists. In unilateral and joint operations, U.S. military
  forces use the WGS 84 horizontal coordinates and height (height above ellipsoid) unless the commander
  determines that the use of other position reference systems (such as horizontal, vertical, or both datum) is
  mission critical. Universal use of the WGS 84 positional reference system (datum) eliminates confusion
  regarding which system to use in reporting positions.
  Military Grid Reference System
  B-9. The Military Grid Reference System (MGRS) is an alpha-numeric system for expressing Universal
  Transverse Mercator (UTM) universal polar stereographic coordinates. A single alpha-numeric value
  references an area unique for the entire earth. The number 15SWC8081751205 illustrates a MGRS
  coordinate. The first two characters represent the 6-degree wide UTM zone. The third character is a letter
  designating the band of latitude. The fourth and fifth characters are a pair of letters designating one of the
  100,000-meter grid squares within the grid zone. The remaining characters consist of the numeric easting
  and northing values within the 100,000-meter grid square. Ten numeric characters equal a one meter
  refinement. Eight numeric characters equal a 10-meter refinement. Six numeric characters equal a 100 meter
  refinement. Four numeric characters equal a 1,000 meter refinement. The MGRS is the most commonly used
  point reference system by Soldiers.
  Geographic Coordinates
  B-10. The use of geographic coordinates as a system of reference is accepted worldwide. It is based on the
  expression of position by latitude (parallels) and longitude (meridians) in relation to the equator (north and
  south) and a prime meridian (east and west). The map scale and the accuracy requirements for plotting and
  scaling influence the degree of accuracy of a geographic reference. The U.S. military uses two formats to
  show location that sometimes leads to confusion for airspace element personnel. The Army generally
  expresses position in degrees, minutes (60 to a degree), and seconds (60 to a minute). An example of a
  geographic reference referenced to degrees, minutes, and seconds of latitude and longitude found in an
  operation order is: 40°21’12” N 132°14’18” E. Joint and civil aviation express geographic reference position
  using the sexagesimal system using degrees, minutes, and decimal minutes (DDMM.mmmm). The same
  location given in the previous example is found in air tasking order or ACO expressed as 40°21.2000 N
  132°14.3000 E. Army digital airspace systems translate between methods automatically. For manual data
  entry into a digital system, the operator just needs to select the correct format. If an airspace Soldier needs to
  convert locations manually from one format to another, the conversion is simple. There is no change to the
  degrees or whole minutes, only the seconds or decimal portion of the decimal minute are converted. To
  convert seconds to decimal minutes divide the seconds by 60 (for example, 12/60=.2). The product is the