Contents

3-axis spacecraft with an IMU simulation

%--------------------------------------------------------------------------
%   Copyright (c) 2016 Princeton Satellite Systems, Inc.
%   All rights reserved.
%--------------------------------------------------------------------------
%   Since 2016.1
%--------------------------------------------------------------------------


% Time
nDays = 0.1;
dT    = 0.5;
tEnd	= nDays*86400;
n     = ceil(tEnd/dT);

Initialize

With LN-200S parameters

d                       = RHSSpacecraftWithIMU;
d.iMU.randomWalk1Sigma	= [0;0;0;0.07;0.07;0.07];
d.iMU.wideband1Sigma    = [35;35;35;0;0;0]; % micro-g
d.iMU.sampleFrequency   = 1/dT;

% Gyro properties
d.iMU.rho           = [0.5;0.5;0.5];


% Circular orbit
r     = 7000;
v     = sqrt(d.mu/r);
omega = [0.1;0;0];
d.iMU = IMU('initialize',d.iMU);

Assemble the state vector and simulate

x     = [r;0;0;0;v;0;omega;[1;0;0;0];zeros(9,1)];
xP    = zeros(length(x)+6,n);

for k = 1:n

  % Get the acceleration vector
  xDot    = RHSSpacecraftWithIMU(x,0,d);

  % IMU output [accel;rate]
  iMUO    = IMU('output',xDot,x,d.iMU);

  % Plotting
  xP(:,k)	= [x;iMUO];

  % State propagation
  x       = RK4(@RHSSpacecraftWithIMU,x,dT,0,d);
end

Plot

[t,tL] = TimeLabl((0:(n-1))*dT);

yL     = {'a_x' 'a_y' 'a_z' '\theta_x','\theta_y','\theta_z'};
Plot2D(t,xP(23:28,:),tL,yL,'IMU output')


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Published with MATLAB® R2019a