EPHEMERIS FILE

Ephemeris data will be written in 32-bit positive integer form (31 data bits with the MSB set to O). Offset and bias values will be provided to convert the positive integer values to true units. For altitudes less than 3 earth radii, the data will occur at a rate of once per minute. For higher altitudes, the rate will be once per 5 minutes.

To convert the 32-bit positive integer data into proper units, a table of offset and bias values will be provided.

                  WORD           DESCRIPTION

    1           JULIAN DATE (DAYS)
    2           UT (MILLISECONDS)
   3            X, SATELLITE POSITION,  ECI  (KM)
   4            Y, SATELLITE POSITION,  ECI  (KM)
   5            Z, SATELLITE POSITION,  ECI  (KM)
   6            VX,  SATELLITE VELOCITY,  ECI  (KM/SEC)
   7            VY,  SATELLITE VELOCITY,  ECI  (KM/SEC)
   8            VZ,  SATELLITE VELOCITY,  ECI  (KM/SEC)
   9            RADIUS, EARTH CTR TO SATELLITE (KM)
   10           ALTITUDE (KM)
   11           LATITUDE (DEG)
   12           LONGITUDE (DEG)
   13           VELOCITY (KM/SEC)
   14           LOCAL TIME (HR)
   15           RADIUS, MAG (EMR)
   16           LATITUDE, MAG (DEG)
   17           LONGITUDE, MAG (DEG)
   18           RADIUS, SM (EMR)
   19           LATITUDE, SM (DEG)
   20           LOCAL TIME, SM (HR)
   21          RADIUS, GSM (EMR)
   22          LATITUDE, GSM (DEG)
   23          LOCAL TIME, GSM (HR)
   24          B, (nT)
   25          BX,  ECI  (nT)
   26          BY,  ECI  (nT)
   27          BZ,  ECI  (nT)
   28          MAGNETIC LOCAL TIME (HR)
   29          SOLAR ZENITH ANGLE (DEG)
   30          INVARIANT LATITUDE (DEG)
   31          B100N LATITUDE   (DEG)
   32          B100N LONGITUDE  (DEG)
   33          B100S LATITUDE   (DEG)
   34          B100S LONGITUDE  (DEG)
   35          L-SHELL   (EMR)
   36          BMIN   (nT)
   37          BMIN LATITUDE    (DEG)
   38          BMIN LONGITUDE   (DEG)
   39          BMIN ALT (KM)
   40          BCONJ LATITUDE (DEG)
   41          BCONJ LONGITUDE (DEG)
   42          BCONJ ALT (KM)
   43          X SUN POSITION-ECI  (KM)
   44          Y SUN POSITION-ECI  (KM)
   45          Z SUN POSITION-ECI  (KM)
   46          X MOON POSITION- ECI (KM)
   47          Y MOON POSITION-ECI (KM)
   48          Z MOON POSITION-ECI (KM)
   49          RIGHT ASCENSION OF GREENWICH
   50          B100N MAG FIELD (nT)
   51          B100S MAGNETIC FIELD (nT)
   52          Mx DIPOLE MOMENT-ECI (nT)
   53          My DIPOLE MOMENT-ECI (nT)
   54          Mz DIPOLE MOMENT-ECI (nT)
   55          Dr DIPOLE OFFSET-ECI (KM)
   56          Dy DIPOLE OFFSET-ECI (KM)
   57          Dz DIPOLE OFFSET-ECI (KM)
   58-60       VACANT

(A)   MAG - MAGNETIC COORDINATES; THE Z AXIS IS PARALLEL TO THE DIPOLE, AND THE SOUTH GEOGRAPHIC POLE IS IN THE +X,Z PLANE.

(B)   SM - SOLAR MAGNETIC COORDINATES; THE Z AXIS IS PARALLEL TO THE DIPOLE, AND THE SUN IS IN THE +X,Z PLANE.

(C)   GSM - GEOCENTRIC SOLAR MAGNETOSPHERIC COORDINATES; THE X-AXIS IS PARALLEL TO THE EARTH - SUN LINE, AND THE EARTH'S DIPOLE IS IN THE X,+Z PLANE.

(D)   EMR P 6371.2 KM

(E)   THE EQUATORIAL RADIUS IS DEFINED AS 6378.135 R~, AND THE FLATTENING IS 298.26.