
% CometPosition: Make observations of the Comet position at
% certain times and with a certain noise level.
%
function [ CometPosition ]=CometObservation( Time , NoiseLevel );

%
% Default value for the NoiseLevel
%
  if nargin<2
      NoiseLevel=0.5*10^-2;
  end
  
% Create a set of observation of the Comet position at certain times.
% At time t=0 the comet is positioned at "angle theta=0" and it 
% travels with a constant angle-velocity. 
  
  CometAngleVelocity=0.57;
  theta=Time*CometAngleVelocity;
  P=[3,1;-2,4]*[sin(theta);cos(theta)];
  P=P+NoiseLevel*randn(size(P));
  CometPosition=P+[10,0;0,-3]*ones(size(P));

end