Code covered by the BSD License
atan3 (a, b)
four quadrant inverse tangent
brent (f, x1, x2, rtol)
solve for a single real root of a nonlinear equation
eqxra (tjd, k)
this function computes the intermediate right ascension
erot (date1, date2)
this function returns the value of the earth rotation angle
etilt1 (tjd)
this function computes quantities related to the orientation
funarg (t)
this function computes fundamental arguments (mean elements)
gast4 (tjdh, tjdl, k)
this function computes the greenwich sidereal time
get_utc_time
interactive request and input of universal coordinated time
getdate
interactive request and input of calendar date
getoe(ioev)
interactive request of classical orbital elements
gravity (t, y)
first order equations of orbital motion
julian (month, day, year)
Julian date
kepler1 (manom, ecc)
solve Kepler's equation for circular,
kozai1 (iniz, t, oev1)
analytic orbit propagation
nut2000_lp (t)
low precison nutation based on iau 2000a
obliq(t)
function to compute mean obliquity of the ecliptic in arcseconds
orb2eci(mu, oev)
convert classical orbital elements to eci state vector
readgm(fname)
read gravity model data file
repeat_eqm (t, y)
first order equations of orbital motion
rkf78 (deq, neq, ti, tf, ... solve first order system of differential equations
rpt2func(x)
rz objective function
rpt4fun1 (x)
delta-fundamental interval objective function
sun2 (jdate)
precision ephemeris of the Sun
times_novas (tdbjd)
this function computes the terrestrial time (tt) julian date
repeat1.m
repeat2.m
repeat3.m
repeat4.m
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Repeating Ground Track Orbit Design
by
David Eagle
19 Nov 2012
(Updated
06 Sep 2013 )
Four MATLAB scripts for designing and analyzing repeating ground track orbits.
rpt2func(x)
function fx = rpt2func(x)
% rz objective function
% required by repeat2.m and repeat4.m
% Orbital Mechanics with MATLAB
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
global tiwrk yi yfinal
% number of differential equations
neq = 6;
% step size guess
h = 60.0;
% integrate from tiwrk to requested time = x
tetol = 1.0e-10;
yfinal = rkf78('repeat_eqm', neq, tiwrk, x, h, tetol, yi);
% compute current value of z component of position vector
fx = yfinal(3);
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