function testperf
x=rand(36,1); P=rand(36); P=P'*P; n=10;
y0=rand(n,1); h0=rand(n,1); H0=rand(n,35); R0=diag(rand(n,1));
tic
for m=1:86400*2
    i=[1:5,11:21]; y=y0; h=h0; H=H0(:,i); R=R0;
    [x(i),P(i,i)]=filterekf(x(i),P(i,i),y-h,H,R,0);
end
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