diff --git a/mr/ub9/loc_framework/ukf_correction.m b/mr/ub9/loc_framework/ukf_correction.m
index b526e96..aaa2a1f 100644
--- a/mr/ub9/loc_framework/ukf_correction.m
+++ b/mr/ub9/loc_framework/ukf_correction.m
@@ -9,7 +9,9 @@
 for i =1:size(X,2)
     Z(:,i)= measurement(X(:,i));
 end
-[expX,covX]=ukf_estimate_normal( X, w );
+expX=pred_mean;
+covX=pred_cov;
+%[expX,covX]=ukf_estimate_normal( X, w );
 [expZ,CovOfIn]=ukf_estimate_normal( Z, w );
 CovOfIn = CovOfIn+Q;
 
diff --git a/mr/ub9/loc_framework/ukf_estimate_normal.m b/mr/ub9/loc_framework/ukf_estimate_normal.m
index d59915a..47fa26d 100644
--- a/mr/ub9/loc_framework/ukf_estimate_normal.m
+++ b/mr/ub9/loc_framework/ukf_estimate_normal.m
@@ -20,7 +20,7 @@
 for i =1:n
     cov = cov+ w(i)*(S(:,i)-mu)*(S(:,i)-mu)';
 end
-    
+ 
 
 % YOUR CODE END HERE:
 
diff --git a/mr/ub9/loc_framework/ukf_sigma_points.m b/mr/ub9/loc_framework/ukf_sigma_points.m
index a185737..afda9c4 100644
--- a/mr/ub9/loc_framework/ukf_sigma_points.m
+++ b/mr/ub9/loc_framework/ukf_sigma_points.m
@@ -24,6 +24,11 @@
 w(1)=1/3;
 w(2:n)=(1-w0)/(2*nx);
 
+if (sqrtm(cov)^2 ~= cov)
+    cov
+    sqrtm(cov)^2
+end
+
 RootN= sqrt(nx/(1-w0))*sqrtm(cov);
 
 for i =1:nx