ATP-3-09-02 Field Artillery Survey Download
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Ellipsoids and Datums 16 February 2016 ATP 3-09.02 C-3 except that the second degree zonal used is that of the WGS-84 gravitational model instead of the notation J 2 used for GRS-80. Because of that difference, the ellipsoid parameters differ slightly between GRS-80 and WGS-84. These differences are insignificant from a practical application standpoint; therefore, it has been accepted that GRS-80 and WGS-84 are the same and their associated datums are based on the same ellipsoid. Even so, it must be understood that WGS-84 is datum within the WGS-84 ellipsoid, and NAD-83 is a datum referenced to the GRS-80 ellipsoid. C-7. WGS-84 is the preferred ellipsoid and datum for all mapping, charting, and geodetic products. Some areas of the world can still be covered by other systems. DATUM TRANSFORMATION TABLES C-8. Datum transformation tables (figures C-2 on page C-4) include the following information: Continent name. Local geodetic datum name and code. The datum name as it appears in Defense Mapping Agency (DMA) TR 8350.2. In cases where a datum has more than one name, the second name is listed in parentheses. Reference ellipsoids and parameter differences, to include: Ellipsoid name. ∆a, which is the difference between the semimajor axes of the local reference ellipsoid and WGS-84. ∆f x 10 4 which is the difference between the flattening of the local reference ellipsoid and WGS-84 multiplied by 10 4 . Note. Both ∆a and ∆f x 10 4 are necessary for the user-defined option in the AN/PSN-11 (PLGR) Version V04b.2. Transformation parameters, to include: Cycle number. A cycle number of zero indicates that the set of parameters is as it was published in DMA TR 8350.2, Second Edition, 1 September 1991 including Insert 1, 30 August 1993 or that the parameters are new to this edition (1997 Publication Date). A cycle number of one indicates that the current parameters have replaced outdated parameters that were in the previous edition. Publication date. ∆X axis. Intersection of the International Earth Rotation Service Reference Meridian and the plane passing through the origin and normal to the Z-axis. ∆Y axis. Completes a right-handed, Earth-Centered Earth-Fixed orthogonal coordinate system. ∆Z axis. The direction of the International Earth Rotation Service Reference Pole. This direction corresponds to the direction of the Bureau International de l’Heure Conventional Terrestrial Pole.