The Astrodynamic Standards were developed to ensure interoperability for users of the Joint Space Operations JSpOC satellite catalog. In order to obtain the most accurate prediction, users need to apply the same propagator models that were used to generate the satellite catalog. The accuracy of an Astrodynamic Standard algorithm is primarily a function of its underlying physics model and the accuracy and compatibility of the data it uses. It is easy to understand that the "better" the underlying physics model or the more accurate the data, the more accurate the algorithm's calculation. However, it is not as intuitively obvious that the prediction model must also be compatible with those models generating the orbital data that it uses as input. The bottom line is, if you are a user of the JSpOC satellite catalog (either TLEs or Vector Covariance Messages (VCMs)), you should use the same propagators that were used to generate the TLEs or VCMs in order to get the most accurate prediction.
DSoft Technology is well-versed in using and integrating Astrodynamic Standards, having worked with the standards and Air Force Space Command since 2003. Since then we have performed configuration management, testing, integration, and distribution of the Astrodynamic Standards and understand the complexity of their integration and use. We can assist authorized clients to integrate the standard DLLs into other applications using a C# wrapper.
The following describes each standard in more detail:
AOF computes when overhead satellites can see a particular location on the earth. AOF uses both SGP4 and SP for ephemeris generation.
Breakup Analysis Model
This program assists in determining the time and location of a satellite breakup.
Batch Differential Correction
Performs a least squares batch differential correction of orbital elements using tracking data and both the SGP4 and SP propagator. The BatchDC now combines the old SGP4DC and SPDC.
Computation of Coplaner Orbits
This program compares one elset against other elsets to find coplanar orbits.
Computation of Miss Between Orbits
Computes close approaches between satellites using both SGP4 and SP for ephemeris generation.
Element Set Comparisons
This program compares element sets.
Field of View
FOV determines times in which orbiting satellites fly through a ground based observer's conical field of view. The field of view can be defined by a constant azimuth and elevation, a constant right ascension and declination, or as a line-of-site to another orbiting satellite. FOV uses both SGP4 and SP for ephemeris generation.
Generalized Element Conversion
Converts element sets or vectors of one of three theories (SGP4, SALT, or SP) to element sets or vectors of a selected theory (SGP4, SALT, or SP).
Initial Orbit Generation; Name carried over from Initial Orbit Module
Computes an initial set of orbital elements from three observations.
Look Angles Generation, name carried over from Look Angles Module algorithm
Computes sensor (ground based or space based) viewing opportunities (so-called "look angles") for earth centered satellites. LAMOD uses both SGP4 and SP for ephemeris generation.
Associates observations against satellite element sets.
Satellite Attack Assessment Program
This program determines possible direct ascent windows. A zenith centered outreach cone is erected about a lat/lon point and geometries of satellite penetrations of the cone are examined.
Semi-Analytic Liu Theory
Is a semi-analytic method of providing ephemerides and orbital lifetime analysis for satellites in earth-centered orbits.
Sequential Differential Correction
Performs a series of least-squares differential corrections (DC). These differential corrections are computed in a sequential mode, which uses one or more observations or tracks while retrieving former covariance information from a prior DC. SEQDC uses both SGP4 and SP for ephemeris generation.
Simplified General Perturbations #4
Is an analytic method of generating ephemerides for satellites in earth-centered orbits.
SGP4 Differential Correction
Performs a least squares differential correction of orbital elements using tracking data and the SGP4 propagator.
Is an algorithm, which uses numerical integration to generate ephemerides for satellites in earth-centered orbits.
SP Differential Correction
Performs a least squares differential correction of orbital elements using tracking data and the SP propagator.
List of Standards
Click on the list to the left to view more information about the standards that DSoft has worked with.