SGP4 Element Preview/Modify
Preview or modify the GP element information that is used to propagate the SGP4 satellite.
Preview is available if you are using automatic update.
If you are previewing the information you can not edit any values.
Modify is available if you are using Define/Import Elements.
A list of elements are displayed. Highlight an element to preview or modify its details. Displayed on the panel are the following items.
| Item | Description |
|---|---|
| Source | The source from which the GP element data is obtained. |
| Last Updated | The date that the GP element data was updated. |
| Switching Method | The method used to switch between elements, when multiple elements are used. |
| Start Time | The transition time to the selected element determined by the Switching Method. |
| Range | The range between ephemerides produced using this element and the previous element at this element's start time. |
| TLE | The orbital elements of the two-line element. These elements are further described in the following table. |
The following table describes the orbital elements.
| Element | Description |
|---|---|
| Orbit Epoch | The UTC epoch for the elements. The format is YYDDD.DDDDDDDD. The greyed-out field that appears beneath the Orbit Epoch displays the TLE data format, which is YYDDD.<decimal equivalent of day>. |
| Mean Motion | A measure of the osculating period of the orbit, expressed as an angular rate. |
| Eccentricity | Describes the shape of the ellipse. A value of 0 represents a circular orbit; values greater than 0 but less than 1 represent ellipses of varying degrees of ellipticality. |
| Inclination | The angle between the angular momentum vector (perpendicular to the plane of the orbit) and the inertial Z-axis. |
| Argument of Perigee | The angle from the ascending node to the eccentricity vector (lowest point of orbit) measured in the direction of the satellite's motion. The eccentricity vector points from the center of the Earth to perigee with a magnitude equal to the eccentricity of the orbit. |
| RAAN | The angle from the inertial X-axis to the ascending node. The ascending node is the point where the satellite passes through the inertial equator moving from south to north. Right ascension is measured as a right-handed rotation about the inertial Z-axis. |
| Mean Anomaly | The angle from the eccentricity vector to a position vector, where the satellite would be if it always moved at its average angular rate. |
| Mean Motion Dot | The first time derivative of mean motion. |
| Motion Dot Dot | The second time derivative of mean motion. |
| Classification | A one-letter classification indicator.
|
| Bstar | The drag term for the satellite. |
| Rev. Number | The pass number of the object at the orbit epoch shown. |
| Int'l Designator | The international designation of the satellite |