struct

Kozai::SGP4::GravityModel

Inherits Struct < Value < Object

The gravitational constants the propagator is defined on.

NOTE: use .wgs72. The others exist so that the choice is explicit and so that the consequences of getting it wrong can be demonstrated in a test, not because there is ever a reason to prefer them. SGP4's coefficients were derived against WGS-72 and the element sets in circulation are fitted with it; using WGS-84 here introduces an error of several kilometres while looking like an upgrade.

Constructors

new(mu : Float64, radius_km : Float64, j2 : Float64, j3 : Float64, j4 : Float64)
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wgs72

WGS-72. The model SGP4 is defined on, and the correct choice.

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wgs84

WGS-84. Provided for comparison only; do not propagate with it.

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Instance methods

j2

Second zonal harmonic.

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j3

Third zonal harmonic.

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j3oj2

j3 divided by j2.

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j4

Fourth zonal harmonic.

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mu

Gravitational parameter, km³/s².

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radius_km

Equatorial radius, km.

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tumin

Minutes in one time unit.

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xke

Square root of mu in earth radii per minute.

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