ID |

PRN of the SVN |

Health |

000=usable |

Eccentricity |

This shows the amount of the orbit deviation from circular
(orbit). It is the distance between the foci divided by the length of the
semi-major axis (our orbits are very circular). |

Time of Applicability |

The number of seconds in the orbit when the almanac was
generated. Kind of a time tag. |

Orbital Inclination |

The angle to which the SV orbit meets the equator (GPS is
at approximately 55 degrees). Roughly, the SV's orbit will not rise above
approximately 55 degrees latitude. The number is part of an equation: # =
π/180 = the true inclination. |

Rate of Right Ascension |

Rate of change in the measurement of the angle of right
ascension as defined in the Right Ascension mnemonic. |

SQRT(A) Square Root of Semi-Major Axis |

This is defined as the measurement from the center of the
orbit to either the point of apogee or the point of perigee. |

Right Ascension at Time of Almanac (TOA) |

Right Ascension is an angular measurement from the vernal
equinox ((OMEGA)_{0}). |

Argument of Perigee |

An angular measurement along the orbital path measured from
the ascending node to the point of perigee, measured in the direction of the
SV's motion. |

Mean Anomaly |

Angle (arc) traveled past the longitude of ascending node
(value = 0±180 degrees). If the value exceeds 180 degrees, subtract
360 degrees to find the mean anomaly. When the SV has passed perigee and
heading towards apogee, the mean anomaly is positive. After the point of
apogee, the mean anomaly value will be negative to the point of
perigee. |

a_{f0} |

SV clock bias in seconds. |

a_{f1} |

SV clock drift in seconds per seconds. |

Week |

GPS week (0000–1023), every 7 days since 1999 August 22. |