AMSAT Keplerian Format

The Radio Amateur Satellite Corporation (AMSAT) developed its own verbose Keplerian element format.  This format was developed to be convenient for relay over amateur radio and for clarity. Early amateur satellite tracking was manual to some degree.

AMSAT Format:

Satellite: ISS (ZARYA)
Catalog number: 25544
Epoch time:      00225.77853128
Element set:     954
Inclination:       51.5750 deg
RA of node:      210.9643 deg
Eccentricity:    0.0011506
Arg of perigee:  237.0618 deg
Mean anomaly:    183.7134 deg
Mean motion:   15.71169901 rev/day
Decay rate:      4.6489e-4 rev/day^2
Epoch rev:           9881
Checksum:              307

The AMSAT Keplerian format is essentially a labeled subset of the TLE Keplerian format.  The AMSAT format does not have the TLE's International Designator, Ephemeris Type, or its nddot/6 or Bstar drag terms.  The decay rate is the ndot/2 drag term.

The AMSAT format has a single check sum computed by adding all the Keplerian element's digits, a "+1" for each negative (-) sign, and a "+2" for each plus (+) sign. Note that the digits used for computing the check sum include all characters whether they are the orbital parameters themselves or the labels (such as the "2" in the decay units label).


The AMSAT Keplerian elements give most of the information contained in the TLE Format

This format is more verbose, but labels the elements