Data Provider Groups | Data Provider Elements

Brouwer-Lyd Mean Short

These are the Mean Elements considering just the short-period terms from the Brouwer-Lyddane theory, which only include J2 zonal harmonics perturbations. These elements are not time averages of the osculating values but are the results of a specific averaging procedure defined by the theory. In the Brouwer theory, a variation of Delaunay elements are averaged and are therefore the actual mean elements. Other "mean" elements are derived using of osculating orbit element conversions on the computed mean elements. Mean elements are computed in the selected reference frames by first transforming the osculating state to the selected frame and then applying the mean element conversion.

Available for these objects: Satellite

Type: Time-varying data.

Availability: Reports | Graphs | Dynamic Displays | Strip Charts

Data Provider Groups

Data can be requested in a variety of coordinate systems, where the origin of the coordinate system is the object's central body. The available coordinate systems depend on the object's central body. Nominally, the systems Fixed, Inertial, J2000, TrueOfDate, and MeanOfDate are supported, although some central bodies (notably the Earth and Sun) have more.

The following lists the systems available for Earth.

Name	Description
ICRF	International Celestial Reference Frame. The ICRF axes are defined as the inertial (i.e., kinematically non-rotating) axes associated with a general relativity frame centered at the solar system barycenter (often called the BCRF).
MeanOfDate	The mean equator mean equinox coordinate system evaluated at the requested time.
MeanOfEpoch	The mean equator mean equinox coordinate system evaluated at the epoch of the object.
TrueOfDate	The true equator true equinox coordinate system evaluated at the requested time.
TrueOfEpoch	The true equator true equinox coordinate system evaluated at the epoch of the object.
B1950	The mean equator mean equinox coordinate system evaluated at the beginning of the Besselian year 1950 (31 December 1949 22:09:46.866 = JD 2433282.4234591).
TEMEOfEpoch	The true equator mean equinox coordinate system evaluated at the epoch of the object.
TEMEOfDate	The true equator mean equinox coordinate system evaluated at the requested time.
AlignmentAtEpoch	The nonrotating coordinate system coincident with the Fixed system evaluated at the object's coordinate reference epoch.
J2000	The mean equator mean equinox coordinate system evaluated at the J2000.0 epoch (2000 January 1.5 TDB = JD 2451545.0 TDB).

Data Provider Elements

Name	Dimension	Type	Description
Time	Date	Real Number or Text	Time.
Mean Semi-major Axis	Distance	Real Number	Semi-major axis computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include semi-major axis, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean Eccentricity	Unitless	Real Number	Eccentricity computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include eccentricity, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean Inclination	Angle	Real Number or Text	Inclination computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include inclination, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean RAAN	Longitude	Real Number or Text	Right ascension of the ascending node computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include RAAN, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean Arg of Perigee	Angle	Real Number or Text	Argument of periapsis computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include argument of periapsis, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean Mean Anomaly	Angle	Real Number or Text	Mean anomaly computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include mean Anomaly, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean Nodal Period	Time	Real Number	Mean nodal period computed based on the mean element rates for the specified mean element theory. Nodal period is defined time between consecutive crossings of the ascending node.
Mean Arg of Latitude	Angle	Real Number or Text	Argument of latitude computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include argument of latitude, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean Longitude of Perigee	Longitude	Real Number or Text	Longitude of perigee computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include longitude of perigee, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.
Mean Mean Longitude	Longitude	Real Number or Text	Mean longitude computed from mean elements associated with the specified mean element theory. If the elements associated with the mean theory do not include mean longitude, it is computed from the elements associated with the mean element theory using normal osculating orbit element conversions.