Dawn-Dusk SSO eclipse calculations

The Sun-Sync orbit is unique in that the node precesses at a regular rate throughout the year. To analyze the eclipses we therefore need a loop that includes dates for the year and increments the node.

Since version 11.

See also: SunSyncInclination, SunSyncNode, EarthEclipseDuration

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%	 Copyright (c) 2012 Princeton Satellite Systems, Inc.
%    All rights reserved.
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% Main orbit parameters
% h: altitude of the circular orbit
% LTAN: local time of the ascending node
% jD0: epoch
%----------------------------------------
h = 660;
LTAN = 6;
jD0 = Date2JD;

% Compute the corresponding inclination and node
%-----------------------------------------------
e    = 0;
sma  = h + 6378;
inc  = SunSyncInclination( sma, e );
W0   = SunSyncNode( LTAN, jD0 );

% Create the arrays for the year
%-------------------------------
days = 0:364;
jD   = jD0 + days;
W    = W0 + linspace(0,2*pi,length(days));

dMax = zeros(1,length(days));
for k = 1:length(days)
  [d,dMax(k)] = EarthEclipseDuration([sma inc W(k) 0 e 0],jD(k));
end

Plot2D(days,dMax/60,'Days','Eclipse (min)','Eclipse Duration - Dawn-Dusk SSO')


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% PSS internal file version information
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Published with MATLAB® R2020a