Designs earth sensor noise filters for the ComStar satellite.

These filter earth sensor roll and pitch measurements. Earth sensors tend to be very noisy which is a problem for high bandwidth loops. Saves the filter to the mat-file NoiseF.

------------------------------------------------------------------------- See also CButter, StatePrp, ComStar, Plot2D, WriteCM -------------------------------------------------------------------------

Simulation parameters
Filter parameters
Call like this to get a plot
Get the discrete time equations
If requested save and dump the controller matrices

%-------------------------------------------------------------------------------
%	 Copyright 1994-1996 Princeton Satellite Systems, Inc. All rights reserved.
%  Since version 2.
%-------------------------------------------------------------------------------

Simulation parameters

%----------------------
nSim      = 1000;
cMatrices = 'yes'; % If yes will dump matrices to a file and display them

Filter parameters

%------------------
tSamp     = 0.5;
wCutoff   = 1;
nOrder    = 2;

Call like this to get a plot

%-----------------------------
CButter(nOrder,wCutoff);

Get the discrete time equations

%--------------------------------
[a,b,c,d] = CButter(nOrder,wCutoff,tSamp,'Delta');

x     = zeros(length(a),1);
yPlot = zeros(1,nSim);
u     = ComStar('ESA Roll Std')*randn(1,nSim);

for k = 1:nSim
  [yPlot(k),x] = StatePrp(a,b,c,d,x,u(k),'Delta');
end

fprintf(1,'Filter Order       = %12i          \n',nOrder);
fprintf(1,'Filter Cutoff      = %12.8f rad/sec\n',wCutoff);
fprintf(1,'Sampling Period    = %12.8f sec    \n',tSamp);
fprintf(1,'Mean               = %12.8f        \n',mean(yPlot));
fprintf(1,'Attenuation        = %12.8f        \n', std(yPlot)/std(u));

Plot2D(1:nSim,[u;yPlot],'Step','Output','Response to White Noise');

[aN,bN,cN,dN] = CButter(nOrder,wCutoff);

fPath = fileparts(which(mfilename));
save(fullfile(fPath,'NoiseF'),'aN','bN','cN','dN','-v6')

Filter Order       =            2          
Filter Cutoff      =   1.00000000 rad/sec
Sampling Period    =   0.50000000 sec    
Mean               =  -0.00066414        
Attenuation        =   0.43095041

If requested save and dump the controller matrices

%---------------------------------------------------
if( strcmp(cMatrices,'yes') )
  fID           = fopen(fullfile(fPath,'ESANoise.txt'),'w');
  [aD,bD,cD,dD] = CButter(nOrder,wCutoff,tSamp,'Delta');
  WriteCM(fID,'A Matrix','fRollAMatrix',reshape(aD',1,length(aD)^2),12,20,3);
  WriteCM(fID,'B Matrix','fRollBMatrix',bD,12,20,3);
  WriteCM(fID,'C Matrix','fRollCMatrix',cD,12,20,3);
  WriteCM(fID,'D Matrix','fRollDMatrix',dD,12,20,3);
  WriteCM(fID,'A Matrix','fPitchAMatrix',reshape(aD',1,length(aD)^2),12,20,3);
  WriteCM(fID,'B Matrix','fPitchBMatrix',bD,12,20,3);
  WriteCM(fID,'C Matrix','fPitchCMatrix',cD,12,20,3);
  WriteCM(fID,'D Matrix','fPitchDMatrix',dD,12,20,3);
  fclose(fID);
  disp('Noise Filter Matrices')
  disp(aD);
  disp(bD);
  disp(cD);
  disp(dD);
end


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% PSS internal file version information
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