diff --git a/owlps-positioning/src/stock.cc b/owlps-positioning/src/stock.cc
index e258180..5b7d7a4 100644
--- a/owlps-positioning/src/stock.cc
+++ b/owlps-positioning/src/stock.cc
@@ -678,7 +678,10 @@ closest_calibration_request(const Request &request)
       // No non-AP reference point was found, we are forced to consider
       // the AP reference points
       if (i == calibration_requests.end())
-        ignore_aps = false ;
+        {
+          i = calibration_requests.begin() ;
+          ignore_aps = false ;
+        }
     }
 
   float distance = i->ss_square_distance(request) ;