MLDesign Technologies, Inc.

% Demo: EOS satellite in emergency mode
%
% This demo simulates an EOS satellite in emergency
% mode. The satellite is rotated about its y-axis
% by 55 deg and is spinning about its x-axis with
% a rate of 1 rpm
%

removeAll;
clearGraphic();
setSimEpoch(2000,3,21,12,0,0);
addEpoch('equinox',2000,3,21,12,0,0);
noon   = 0;
six_am = -90;
addSatellite('EOS Sat',7171,0,98,six_am,0,0,'equinox');

%earthstation
earth0 = "Frankfurt";
addStation('Frankfurt', I_earth, 10, 50.05, 8.4, 0.1);
dtime = 4;
alphaleft = 55 *d2r;
t = 0:dtime:2000*dtime;
fleft0 = roty(alphaleft)*[ 0
                           1
                           0 ];

setSimTime(0);
setSimStepSize(dtime);

%
% Solar Panel: current(temperature, voltage) for a 
% reference flux of 1353

z_matrix = 
[   0 26.75 27.25 27.75 28.25 28.75 29.25 29.75 30.25 30.75 31.25
  100 12.39 12.23 12.14 12.14 11.95 10.64 10.51 10.33 10.14  9.94
   90 12.67 12.59 12.50 12.39 12.26 11.76 11.68 11.36 11.48 11.36
   80 12.77 12.73 12.68 12.63 12.57 12.31 12.27 12.22 12.17 12.11
   70 12.78 12.76 12.74 12.71 12.68 12.55 12.53 12.51 12.48 12.45
   60 12.74 12.73 12.72 12.71 12.69 12.63 12.62 12.61 12.60 12.68
   50 12.68 12.68 12.67 12.67 12.66 12.63 12.63 12.62 12.62 12.91
   40 12.61 12.61 12.61 12.61 12.60 12.59 12.59 12.79 12.88 13.18
   30 12.53 12.53 12.53 12.53 12.53 12.53 12.57 12.63 12.73 12.72
   20 12.46 12.45 12.45 12.45 12.45 12.45 12.45 12.45 12.65 12.45
   10 12.38 12.38 12.38 12.38 12.38 12.38 12.38 12.38 12.58 12.38
    0 12.30 12.30 12.30 12.30 12.30 12.30 12.30 12.30 12.40 12.30
  -10 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22
  -20 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14
  -30 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06
  -40 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98
  -50 11.70 11.84 11.90 11.90 11.90 11.90 11.90 11.90 11.90 11.90
  -60 11.32 11.62 11.72 11.82 11.82 11.82 11.82 11.82 11.82 11.82
  -70 11.14 11.24 11.44 11.64 11.74 11.74 11.74 11.74 11.74 11.74
  -80 10.95 10.95 11.35 11.45 11.65 11.65 11.65 11.65 11.65 11.65 ];

j         = 0;
templeft  = 0;
solarflux = 1420;
alpha     = 0.65;
epsilon   = 0.81;
albedo    = 0.3;
sigma     = 5.67e-8;
capacity  = 660;
qir       = 0;

num_of_strings = 36;
eview = 0.045;
dt    = 60;
gamma = 0;
reference_flux_si = 1353;
voltage = 28;
current = zeros(size(t));

for i=t,
    j=j+1;
    
    stepSim;
    [d,r,a,e,v] = PlanetPosition();
    gamma = i/30*pi;
    fleft = rotx(gamma) * fleft0;
    theta = fleft` * unitvector(a(2),e(2));
    theta = theta*v(2);
    theta = max(0,theta);
    templeft = templeft+((((theta*solarflux*alpha)
               + (theta*solarflux*albedo*alpha*eview))
               - (epsilon*(templeft^4)*sigma)+theta*qir)
               * (dt/capacity));
    current(j) = ( (num_of_strings*theta)
                  *table(z_matrix,(templeft-273.15),voltage)
                  *((solarflux/reference_flux_si)/12));
endfor

average = sum(current*voltage)/prod(size(t));

erase
window('111');
plot(t,current*voltage,
     t,ones(size(t))*average, 'grid');
title('6 a.m. Power in emergency mode')
ylabel('P [Watt]');
xlabel('t [sec]')