## Area Overflight

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.

## Report/Observation Association

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.

## Special Perturbations

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.