diff --git a/owlps-positioner/positioning.cc b/owlps-positioner/positioning.cc
index aaa14e5..e083822 100644
--- a/owlps-positioner/positioning.cc
+++ b/owlps-positioner/positioning.cc
@@ -18,7 +18,10 @@
 #include "frbhmbasic.hh"
 #include "interlinknetworks.hh"
 #include "nss.hh"
+#include "request.hh"
+#include "result.hh"
 #include "resultlist.hh"
+#include "timestamp.hh"
 #include "configuration.hh"
 #include "posexcept.hh"
 #include "stock.hh"
@@ -128,17 +131,12 @@ void Positioning::loop()
 {
   vector<PositioningAlgorithm*>::const_iterator algo ;
 
-  float filter_max_speed =
-    Configuration::float_value("positioning.filter.max-speed") ;
-
   while (! input.eof() && owl_run)
     {
       const Request &request = input.get_next_request() ;
       if (! request)
         continue ;
 
-      const Mobile *const mobile = request.get_mobile() ;
-
       Point3D real_position ;
       bool compute_error = false ;
       ResultList results(&request) ;
@@ -147,7 +145,6 @@ void Positioning::loop()
           const string &algo_name = (*algo)->get_name() ;
 
           Result res ;
-
           try
             {
               res = (*algo)->compute(request) ;
@@ -161,43 +158,8 @@ void Positioning::loop()
               continue ;
             }
 
-          // Apply filter if the filter is enabled and that it is not the
-          // first result we compute for this mobile
-          if (filter_max_speed > 0
-              && ! mobile->get_last_results().empty()
-              && algo_name != "Real") // don't filter the real position
-            {
-              const ResultList &last_results = mobile->get_last_results() ;
-              const Result &prev_res =
-                last_results.get_result_for_algo(algo_name) ;
-
-              // Calculate the travel time (duration)
-              const Timestamp &timestamp =
-                res.get_request()->get_time_sent() ;
-              const Timestamp &prev_timestamp =
-                last_results.get_request()->get_time_sent() ;
-              Timestamp duration = prev_timestamp.elapsed(timestamp) ;
-
-              // Get the current and previous coordinates
-              const Point3D &pos = res.get_position() ;
-              const Point3D &prev_pos = prev_res.get_position() ;
-
-              // Recompute the result by interpolation
-              Point3D filtered_pos(
-                prev_pos.interpolate(pos, filter_max_speed, duration)) ;
-              if (filtered_pos != pos)
-                {
-                  if (Configuration::is_configured("verbose"))
-                    cerr
-                        << "Filtering (algorithm " << algo_name << "): "
-                        << "for request sent at " << timestamp
-                        << " by mobile " << mobile->get_mac_addr()
-                        << ", " << pos
-                        << " was replaced by " << filtered_pos
-                        << ".\n" ;
-                  res.set_position(filtered_pos) ;
-                }
-            }
+          // Apply filtering if needed
+          filter(request, res) ;
 
           if (compute_error)
             res.compute_error(real_position) ;
@@ -212,9 +174,68 @@ void Positioning::loop()
 
       // If filtering is enabled, update the last known position(s) of
       // the current mobile
-      if (filter_max_speed > 0)
-        const_cast<Mobile*>(mobile)->set_last_results(results) ;
+      bool do_filter =
+        Configuration::float_value("positioning.filter.max-speed") > 0 ;
+      if (do_filter)
+        {
+          const Mobile *const mobile = request.get_mobile() ;
+          const_cast<Mobile*>(mobile)->set_last_results(results) ;
+        }
 
       output.write(results) ;
     }
 }
+
+
+/**
+ * @param[in] request The request from which `result` has been computed.
+ * @param[in,out] result The unfiltered Result, that will be updated by
+ * this function if needed.
+ */
+void Positioning::filter(const Request &request, Result &result)
+{
+  // Don't apply filter if filtering is disabled
+  float max_speed =
+    Configuration::float_value("positioning.filter.max-speed") ;
+  if (max_speed <= 0)
+    return ;
+
+  // Don't apply filter if it is the first result we compute for this
+  // mobile (hence we don't have previous results to compare to)
+  const Mobile *const mobile = request.get_mobile() ;
+  const ResultList &last_results = mobile->get_last_results() ;
+  if(last_results.empty())
+    return ;
+
+  // Don't apply filter if the "algorithm" is the real position
+  string algo_name = result.get_algorithm() ;
+  if (algo_name == "Real")
+    return ;
+
+  const Result &prev_result = last_results.get_result_for_algo(algo_name) ;
+
+  // Calculate the travel time (duration)
+  const Timestamp &timestamp = result.get_request()->get_time_sent() ;
+  const Timestamp &prev_timestamp =
+    last_results.get_request()->get_time_sent() ;
+  Timestamp duration = prev_timestamp.elapsed(timestamp) ;
+
+  // Get the current and previous coordinates
+  const Point3D &pos = result.get_position() ;
+  const Point3D &prev_pos = prev_result.get_position() ;
+
+  // Recompute the result by interpolation
+  Point3D filtered_pos(prev_pos.interpolate(pos, max_speed, duration)) ;
+  if (filtered_pos != pos)
+    {
+      if (Configuration::is_configured("verbose"))
+        cerr
+            << "Filtering (algorithm " << algo_name << "): "
+            << "for request sent at " << timestamp
+            << " by mobile " << mobile->get_mac_addr()
+            << ", " << pos
+            << " was replaced by " << filtered_pos
+            << ".\n" ;
+      result.set_position(filtered_pos) ;
+    }
+}
diff --git a/owlps-positioner/positioning.hh b/owlps-positioner/positioning.hh
index 8e6b10c..25c9ab0 100644
--- a/owlps-positioner/positioning.hh
+++ b/owlps-positioner/positioning.hh
@@ -16,6 +16,8 @@
 #define _OWLPS_POSITIONING_POSITIONING_HH_
 
 class PositioningAlgorithm ;
+class Request ;
+class Result ;
 
 #include "input.hh"
 #include "output.hh"
@@ -33,6 +35,8 @@ protected:
 
   void initialise_algorithms(void) ;
   void loop(void) ;
+  /// Sets a new filtered position in `result`
+  void filter(const Request &request, Result &result) ;
 
 public:
   Positioning(void) ;