Solar Radiation Pressure

To model solar radiation pressure (SRP), select Use and then select the SRP model that you want to use. The available models are described in the following table:

Model	Description
GPS_BlkIIA_AeroT20	Aerospace T20 solar radiation pressure model for GPS block IIA.¹
GPS_BlkIIR_AeroT30	Aerospace T30 solar radiation pressure model for GPS block IIR.¹
GPS_BlkIIA_GSPM04a	Bar-Sever GPS Solar Pressure Model 04a for block IIA.²
GPS_BlkIIR_GSPM04a	Bar-Sever GPS Solar Pressure Model 04a for block IIR.²
GPS_BlkIIA_GSPM04ae	Bar-Sever GPS Solar Pressure Model 04ae for block IIA.³
GPS_BlkIIR_GSPM04ae	Bar-Sever GPS Solar Pressure Model 04ae for block IIR.³
Spherical SRP	Solar radiation pressure model that assumes a spherical spacecraft.

^1. O’Toole, James W., "Mathematical Description of the OMNIS Satellite Orbit Generation Program (OrbGen)", NSWCDD/TR-02/118, May 2004.

Fliegel, H.F., Gallini, T.E., Swift, E.R., "Global Positioning System Radiation Force Model for Geodetic Applications", Journal of Geophysical Research, Volume 97, No. B1, January 1992.

Fliegel, H.F., Gallini, T.E., "Solar Force Modeling of Block IIR Global Positioning System Satellites", Journal of Spacecraft and Rockets, Volume 33, No. 6, November-December 1996.

^2. Bar-Sever, Y., Kuang, D., "New Empirically Derived Solar Radiation Pressure Model for Global Positioning System Satellites", IPN Progress Report 42-159, November 15, 2004.

^3. Bar-Sever, Y., Kuang, D., "New Empirically Derived Solar Radiation Pressure Model for Global Positioning System Satellites During Eclipse Seasons", IPN Progress Report 42-160, February 15, 2005.

GPS SRP Model Parameters

The following parameters pertain to GPS SRP models:

Parameter	Description
K1	Defines the K1 (scale) value.
K2	Defines the K2 (Y bias) value.

Spherical SRP Model Parameters

The following parameters pertain to the Spherical SRP model:

Parameter	Description
Cr	Defines the solar radiation pressure coefficient.
Area/Mass Ratio	Defines the area-to-mass ratio to be used in SRP calculations.

General SRP Parameters

The following parameters pertain to all SRP models:

Parameter	Description
Shadow Model	The type of shadow to be used in determining the lighting condition for the satellite. None. Choosing this option turns off all shadowing of the satellite. Cylindrical. The cylindrical model assumes the Sun to be at infinite distance so that all light coming from the Sun moves in a direction parallel to the Sun to satellite vector. Dual Cone. The dual cone model uses the actual size and distance of the Sun to model regions of full, partial (penumbra) and zero (umbra) sunlight. The visible fraction of the solar disk is used to compute the acceleration during penumbra. The primary central body is always considered as an eclipsing body except for the case where the primary central body is the Sun. Additional central bodies to be evaluated for shadowing effects are determined using parent, child and sibling relationships. The hierarchical order in the solar system consists of the Sun, which is the parent of the planets, which in turn are the parents of their moons. The set of eclipsing bodies contains the parent of the primary body (unless the parent is the Sun), the siblings of the primary body (unless the parent is the Sun) and the children of the primary body (unless the primary is the Sun). For example, if either the Earth or the Moon is the primary body then both the Earth and Moon are considered as eclipsing bodies.
Use Boundary Mitigation	The state of the satellite after crossing a shadow boundary is corrected for errors that may have been introduced by the sudden change in the SRP which occurred during the integration step.

Parameter

Description

Shadow Model

The type of shadow to be used in determining the lighting condition for the satellite.

None. Choosing this option turns off all shadowing of the satellite.

Cylindrical. The cylindrical model assumes the Sun to be at infinite distance so that all light coming from the Sun moves in a direction parallel to the Sun to satellite vector.

Dual Cone. The dual cone model uses the actual size and distance of the Sun to model regions of full, partial (penumbra) and zero (umbra) sunlight. The visible fraction of the solar disk is used to compute the acceleration during penumbra.

The primary central body is always considered as an eclipsing body except for the case where the primary central body is the Sun. Additional central bodies to be evaluated for shadowing effects are determined using parent, child and sibling relationships. The hierarchical order in the solar system consists of the Sun, which is the parent of the planets, which in turn are the parents of their moons. The set of eclipsing bodies contains the parent of the primary body (unless the parent is the Sun), the siblings of the primary body (unless the parent is the Sun) and the children of the primary body (unless the primary is the Sun). For example, if either the Earth or the Moon is the primary body then both the Earth and Moon are considered as eclipsing bodies.

Use Boundary Mitigation

The state of the satellite after crossing a shadow boundary is corrected for errors that may have been introduced by the sudden change in the SRP which occurred during the integration step.

Additional options for modeling SRP can be accessed by clicking the More Options... button.