MIL-PRF-89500A, PERFORMANCE SPECIFICATION: WORLD MAGNETIC MODEL (WMM) (30-OCT-2015) [SUPERSEDING MIL-W-89500]

MIL-PRF-89500A, PERFORMANCE SPECIFICATION: WORLD MAGNETIC MODEL (WMM) (30-OCT-2015) [SUPERSEDING MIL-W-89500]., This specification is designed to provide guidelines for the preparation and use of the World Magnetic Model (WMM) and the charts and grid tables derived from the model. This specification also provides guidelines for the preparation and use of computer programs and subroutines that compute the model magnetic field elements, namely the declination (D), inclination (I), total intensity (F), horizontal intensity (H), northerly component (X), easterly component (Y), downward component (Z), and grid variation (GV) at given locations and times