Index: mttroot/mtt/lib/control/PPP/ppp_int_obs.m
==================================================================
--- mttroot/mtt/lib/control/PPP/ppp_int_obs.m
+++ mttroot/mtt/lib/control/PPP/ppp_int_obs.m
@@ -1,6 +1,6 @@
-function [x_new,y_new] = ppp_int_obs (x,y,U,A,B,C,D,A_u,delta,L)
+function [x_new,y_new,error] = ppp_int_obs (x,y,U,A,B,C,D,A_u,delta,L)
 
   ## usage: x_new = ppp_int_obs (x,y,U,A,B,C,D,A_u,delta,L)
   ##
   ## Intermittent observer for PPP
   ##
@@ -20,8 +20,9 @@
   
   ## Predictor
   [y_p,us,x_p] = ppp_ystar (A,B,C,D,x,A_u,U,delta);
 
   ## Corrector
-  x_new = x_p - L*(y_p-y);
+  error = (y_p-y);
+  x_new = x_p - L*error;
   y_new = C*x_new;
 endfunction