Path: CubeSat/Simulation
% Environment calculations for the CubeSat dynamical model.
Uses the J70 atmosphere model or AtmDens2 if the data required by J70 is
absent. Computes sun location with SunV1 and accounts for eclipses from the
Earth via Eclipse. All environment constants including gravity are defined
here.
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Form:
env = CubeSatEnvironment % data structure
env = CubeSatEnvironment( x, t, d )
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Inputs
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x (14,1) State, [r;v;q;w;b]
t (1,1) Time, sec
d (.) Data structure
.jD0 Julian date of epoch
.att (.) Attitude
.atm (.) optional; empty to skip J70 and use AtmDens2
.surfData (.) optional; empty to skip drag/optical calcs
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Outputs
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env (.) Environmental data
.r (3,1) ECI position (km)
.v (3,1) ECI velocity (km/s)
.q (4,1) ECI to body quaternion
.mu (1) Gravitational constant (km3/s2)
.radiusPlanet (1) Radius of the planet (km)
.radiation (1) Planetary radiation at h=0 (W/m2)
.albedo (1) Planet bond albedo fraction
.vRel (3,1) Velocity relative to the atmosphere (km/s)
.rho (1) Atmospheric density (kg/m3)
.uSun (3,1) Sun unit vector (ECI)
.rSun (1) Sun distance (km)
.solarFlux (1) Solar flux at position (W/m2)
.nEcl (1) Eclipse fraction (source intensity, 0-1)
.bField (3,1) Magnetic field, ECI frame (T)
.planetAlb (3,1) Planetary albedo (ECI) (W/m2)
.planetRad (3,1) Planetary radiation (ECI) (W/m2)
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See also SunV1, Eclipse, AtmDens2, AtmJ70, BDipole
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