Centrifugal Effect Model

Implement mathematical representation of centrifugal effect for planetary gravity

Library

Environment/Gravity

Description

The Centrifugal Effect Model block implements the mathematical representation of centrifugal effect for planetary gravity. The gravity centrifugal effect is the acceleration portion of centrifugal force effects due to the rotation of a planet. This block implements this representation using planetary rotation rates. You use centrifugal force values in rotating or non-inertial coordinate systems.

Dialog Box

Planet model

Specify the planetary model. From the list, select Mercury, Venus, Earth, Moon, Mars, Jupiter, Saturn, Uranus, Neptune, or Custom. The block uses the rotation of the selected planet to implement the mathematical representation of the centrifugal effect.

Selecting Custom enables you to specify your own planetary model. This option enables the Planetary rotational rate (rad/sec) and Input planetary rotation rate parameters.

Planetary rotational rate (rad/sec)

Specify the planetary rotational rate in radians per second.

If you want to specify the planetary rotational rate as an input to the block, see the Input planetary rotation rate parameter.

Selecting the Input planetary rotation rate check box disables the Planetary rotational rate (rad/sec) parameter.

Input planetary rotation rate

Select this check box to enable a block input. You can then input a planetary rotation rate as a block input. When you select this check box, the block mask updates to display an input port for the rotation rate.

Selecting the Input planetary rotation rate check box disables the Planetary rotational rate (rad/sec) parameter.

Inputs and Outputs

This block accepts only scalar inputs (m=1).

InputDimension TypeDescription

First

m-by-3 matrixContains planet-centered planet-fixed coordinates from the center of the planet. If Planet model has a value of Earth, this matrix contains Earth-centered Earth-fixed (ECEF) coordinates. The block does not use explicit units.

OutputDimension TypeDescription

First

m-by-3 arrayContains gravity values in the x-axis, y-axis and z-axis of the planet-centered planet-fixed coordinates in input distance units per second squared.

References

Vallado, D. A., Fundamentals of Astrodynamics and Applications, McGraw-Hill, New York, 1997.

NIMA TR8350.2: Department of Defense World Geodetic System 1984, Its Definition and Relationship with Local Geodetic Systems.

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