The orbital parameters provided by Dundee Satellite Receiving Station are formatted as 14-element records, one per line. Each record describes the orbit at a particular moment in time (the epoch).

1. and 2. Day at Epoch (iyr, epoch)
Epoch day of year in GMT (1 <= epoch day < 367), the date of the specified orbital elements. [Integer, Real]
3. Number of revolutions per 24 hours (rev)
[Real]
4. Eccentricity (ecc)
The shape of the orbit where zero defines a circular orbit and higher values indicate a more elliptical orbit (0 <= eccentricity < 1 for Earth orbit). [Real]
5. Argument of perigree at epoch (arpoch)
The angle in the orbital plane from the ascending node to the point of perigee in the direction of the satellite's motion. Perigee is the point in the orbit closest to the Earth's center for an elliptical orbit. [Real: degrees]
6. Inclination of orbit to equatorial plane (einc)
The angle at which the orbit plane crosses the equatorial plane, measured counter-clockwise from east. [Real: degrees]
7. Rate of change of argument of perigee (rargp)
[Real: degrees per day]
8. Right ascension of ascending node (ascnd)
The angle on the equatorial plane from the vernal equinox eastward to the orbit ascending node, the point where the satellite crosses the equator on an ascending pass. The vernal equinox is the ascending node of the Earth's orbit around the Sun. [Real: degrees]
9. Drag term for SGP4 orbital model (bstar)
The drag term for SGP4 orbital model, used for calculating decay constants for altitude, eccentricity etc. The bstar term is only available when source was two-line data, otherwise set to 0 for TBUS data.
10. Orbit number (norb)
The current revolution number. The value is incremented when a satellite crosses the equator on an ascending pass.
11. Mean anomaly at epoch (mnan)
The angle on the orbital plane from the point of perigee to the position of the satellite in the direction of the satellite's motion. [Real: degrees]
12. Greenwich hour angle (aries)
Celestial longitude of Greenwich Meridian at epoch time. [Real: degrees]
13. Semimajor Axis (smjaxs)
Half the size of the major axis of the orbit ellipse. [Real: km]
14. Rate of change of Right Ascension (rascn)
Celestial longitude of satellite when it crosses the equator on an ascending (northbound) pass. [Real: radians per minute] Dundee Satellite Receiving Station Home Page Send Us A Comment 