diff --git a/TODO b/TODO
index 970004d..a20adb3 100644
--- a/TODO
+++ b/TODO
@@ -1,6 +1,9 @@
 * Global
 
-- Use -D DEBUG in makefiles instead of #defines.
+- Makefiles:
+   ° Use -D DEBUG instead of #defines.
+   ° Use echo instead of echo -e.
+   ° Translate comments & help.
 - Use string for network exchanges?
 - Mark arguments as const in function headers if needed
    That is done in the owlps-positioning C++ code, but not constantly
diff --git a/owlps-aggregator/Makefile b/owlps-aggregator/Makefile
index 74abb2a..e2d6985 100644
--- a/owlps-aggregator/Makefile
+++ b/owlps-aggregator/Makefile
@@ -1,6 +1,6 @@
 # Source version
 ifndef OWLPS_VERSION
-	OWLPS_VERSION = $$(git describe || echo 'UNKNOWN_VERSION')
+	OWLPS_VERSION := $(shell git describe 2>/dev/null || echo 'UNKNOWN_VERSION')
 endif
 
 # Répertoire d'installation
diff --git a/owlps-ardrone/owlps-drone.c b/owlps-ardrone/owlps-drone.c
index 355da1c..8fdea39 100644
--- a/owlps-ardrone/owlps-drone.c
+++ b/owlps-ardrone/owlps-drone.c
@@ -711,7 +711,7 @@ void string2data(char* string_data)
   int count_algo= 0 ;
   int count_print = 0 ;
   int onetime = 0 ;
-
+  int error = 0 ;
 
   while(onetime<1)
     {
@@ -761,6 +761,8 @@ void string2data(char* string_data)
       ptr = strtok(NULL, delims) ;
       if(ptr==NULL) break ;
       sscanf(ptr, "%s", results[count_algo].algo) ;
+      if(!strcmp(results[count_algo].algo,"Real"))
+        error=1;
 
       //Lecture du point X
       ptr = strtok(NULL, delims) ;
@@ -815,10 +817,50 @@ void string2data(char* string_data)
             }
         }
       results[count_algo].z = atof(ptr) ;
+  if(error==1)
+        {
+          //Lecture du message Error
+          ptr = strtok(NULL, delims) ;
+          if(ptr==NULL)
+            {
+              if(count_algo==0)
+                {
+                  print_error ("trame");
+                  break ;
+                }
+              else
+                {
+                  print_error ("algo");
+                  count_algo--;
+                  break ;
+                }
+            }
+          results[count_algo].check = ptr ;
+
+          //Lecture valeur Error
+          ptr = strtok(NULL, delims) ;
+          if(ptr==NULL)
+            {
+              if(count_algo==0)
+                {
+                  print_error ("trame");
+                  break ;
+                }
+              else
+                {
+                  perror ("algo");
+                  count_algo--;
+                  break ;
+                }
+            }
+          results[count_algo].err = atof(ptr) ;
 
 
-      count_algo++;
+          count_algo++;
+        }
 
+      else
+        count_algo++;
     }
 
   for(count_print=0;count_print<count_algo;count_print++)
diff --git a/owlps-ardrone/owlps-drone.h b/owlps-ardrone/owlps-drone.h
index 28b2ed0..424cf07 100644
--- a/owlps-ardrone/owlps-drone.h
+++ b/owlps-ardrone/owlps-drone.h
@@ -70,6 +70,7 @@ struct result
   float x;
   float y;
   float z;
+  char *check;
   float err;
 };
 
diff --git a/owlps-client/Makefile b/owlps-client/Makefile
index dd00660..accff24 100644
--- a/owlps-client/Makefile
+++ b/owlps-client/Makefile
@@ -1,6 +1,6 @@
 # Source version
 ifndef OWLPS_VERSION
-	OWLPS_VERSION = $$(git describe || echo 'UNKNOWN_VERSION')
+	OWLPS_VERSION := $(shell git describe 2>/dev/null || echo 'UNKNOWN_VERSION')
 endif
 
 # Répertoire d'installation
@@ -45,17 +45,17 @@ dynamic : $(TARGET)
 static : $(TARGET).static
 all : dynamic static
 
-% : %.o
+# Cancel implicit make rule
+%: %.c
+
+%: %.o
 	$(CC) $(LDFLAGS) $(STRIPFLAGS) $(XCFLAGS) -o $@ $^ $(LIBS)
-%.o : %.c $(HEADER)
+%.static: %.o
+	$(CC) $(STRIPFLAGS) $(XCFLAGS) -o $@ $^ \
+		$(LDFLAGS) $(LIBS) $(STATIC_LIBS) -static
+%.o: %.c $(HEADER)
 	$(CC) $(XCFLAGS) $(OWLPSFLAGS) -c $<
 
-# Compilation du programme
-$(TARGET) : $(TARGET).o $(HEADER)
-
-$(TARGET).static : $(TARGET).c $(HEADER)
-	$(CC) $(LDFLAGS) -static $(STRIPFLAGS) $(XCFLAGS) -o $@ $^ $(LIBS) $(STATIC_LIBS)
-
 
 ## Installation / désinstallation ##
 
diff --git a/owlps-client/Makefile_atheros b/owlps-client/Makefile_atheros
index 8cb08e9..89fbb3c 100644
--- a/owlps-client/Makefile_atheros
+++ b/owlps-client/Makefile_atheros
@@ -1,6 +1,6 @@
 # Source version
 ifndef OWLPS_VERSION
-	OWLPS_VERSION = $$(git describe || echo 'UNKNOWN_VERSION')
+	OWLPS_VERSION := $(shell git describe 2>/dev/null || echo 'UNKNOWN_VERSION')
 endif
 
 # Emplacement de la suite de cross-compilation
diff --git a/owlps-client/Makefile_atheros_openwrt-10.03 b/owlps-client/Makefile_atheros_openwrt-10.03
index 9b57248..27545d2 100644
--- a/owlps-client/Makefile_atheros_openwrt-10.03
+++ b/owlps-client/Makefile_atheros_openwrt-10.03
@@ -1,6 +1,6 @@
 # Source version
 ifndef OWLPS_VERSION
-	OWLPS_VERSION = $$(git describe || echo 'UNKNOWN_VERSION')
+	OWLPS_VERSION := $(shell git describe 2>/dev/null || echo 'UNKNOWN_VERSION')
 endif
 
 # Emplacement de la suite de cross-compilation
diff --git a/owlps-listener/Makefile b/owlps-listener/Makefile
index fd217dd..1c7f66b 100644
--- a/owlps-listener/Makefile
+++ b/owlps-listener/Makefile
@@ -1,6 +1,6 @@
 # Source version
 ifndef OWLPS_VERSION
-	OWLPS_VERSION = $$(git describe || echo 'UNKNOWN_VERSION')
+	OWLPS_VERSION := $(shell git describe 2>/dev/null || echo 'UNKNOWN_VERSION')
 endif
 
 # Répertoire d'installation
diff --git a/owlps-listener/Makefile_atheros b/owlps-listener/Makefile_atheros
index 2604b04..bf5260e 100644
--- a/owlps-listener/Makefile_atheros
+++ b/owlps-listener/Makefile_atheros
@@ -1,6 +1,6 @@
 # Source version
 ifndef OWLPS_VERSION
-	OWLPS_VERSION = $$(git describe)
+	OWLPS_VERSION := $(shell git describe 2>/dev/null || echo 'UNKNOWN_VERSION')
 endif
 
 # Emplacement de la suite de cross-compilation
diff --git a/owlps-listener/owlps-listenerd.c b/owlps-listener/owlps-listenerd.c
index e26898a..dd9f4e4 100644
--- a/owlps-listener/owlps-listenerd.c
+++ b/owlps-listener/owlps-listenerd.c
@@ -741,7 +741,8 @@ void read_packet(u_char *args, const struct pcap_pkthdr *header,
   owl_bool uses_autocalibration_request_port = FALSE ;
   int i ; // Iterator
 
-  memset(request.mobile_ip_addr_bytes, 0, 4) ; // Blank the IP
+  // Blank the request:
+  memset(&request, 0, sizeof(request)) ;
 
   /* Common treatements */
 
@@ -837,14 +838,6 @@ void read_packet(u_char *args, const struct pcap_pkthdr *header,
   memcpy(request.ap_mac_addr_bytes, my_mac_bytes, ETHER_ADDR_LEN) ;
   // Capture time is in the pcap header (net-endian):
   request.start_time = owl_timeval_to_timestamp(header->ts) ;
-  // Transmission time on the mobile is unknown (unless the packet is
-  // an explicit request):
-  memset(&request.request_time, 0, sizeof(owl_timestamp)) ;
-  // Blank position data:
-  request.direction = 0 ;
-  request.x_position = 0 ;
-  request.y_position = 0 ;
-  request.z_position = 0 ;
 
   /* Active mode */
   if (is_explicit_packet
@@ -1065,7 +1058,8 @@ void read_packet(u_char *args, const struct pcap_pkthdr *header,
              owl_mac_bytes_to_string(request.mobile_mac_addr_bytes),
              request_time_str,
              start_time_str,
-             request.antenna_signal_dbm - 0x100,
+             check[RTAP_ANTENNASIGNALDBM] ?
+             request.antenna_signal_dbm - 0x100 : 0,
              owl_ntohf(request.x_position),
              owl_ntohf(request.y_position),
              owl_ntohf(request.z_position),
diff --git a/owlps-positioning/Doxyfile b/owlps-positioning/Doxyfile
index 107a93d..1ccfe40 100644
--- a/owlps-positioning/Doxyfile
+++ b/owlps-positioning/Doxyfile
@@ -31,7 +31,7 @@ PROJECT_NAME           = "OWLPS Positioning"
 # This could be handy for archiving the generated documentation or
 # if some version control system is used.
 
-PROJECT_NUMBER         = 0.9.1
+PROJECT_NUMBER         = $(OWLPS_VERSION)
 
 # The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute)
 # base path where the generated documentation will be put.
diff --git a/owlps-positioning/Makefile b/owlps-positioning/Makefile
index 5545c48..ba8433b 100644
--- a/owlps-positioning/Makefile
+++ b/owlps-positioning/Makefile
@@ -1,6 +1,6 @@
 # Source version
 ifndef OWLPS_VERSION
-	OWLPS_VERSION = $$(git describe || echo 'UNKNOWN_VERSION')
+	OWLPS_VERSION := $(shell git describe 2>/dev/null || echo 'UNKNOWN_VERSION')
 endif
 
 # Directories & files
@@ -24,7 +24,7 @@ MKDIR = mkdir -pv
 # Other tools
 STYLE = astyle --style=gnu --formatted
 CPPCHECK = cppcheck --quiet --enable=all
-DOXYGEN = doxygen >/dev/null
+DOXYGEN = OWLPS_VERSION=$(OWLPS_VERSION) doxygen >/dev/null
 
 # Compilation tools
 COLORGCC := $(shell which colorgcc >/dev/null 2>&1 ; echo $$?)
@@ -133,6 +133,8 @@ $(OBJ_DIR)/%.o: $(SRC_DIR)/%.cc $(SRC_DIR)/%.hh
 	$(LD) $(LDFLAGS) -o $@ $^
 
 # Dependencies
+$(OBJ_DIR)/point3d.o: \
+	$(OBJ_DIR)/posexcept.o
 $(OBJ_DIR)/posutil.o: \
 	$(OBJ_DIR)/posexcept.o
 $(OBJ_DIR)/owlps-positioning.o: \
@@ -243,7 +245,9 @@ $(OBJ_DIR)/output.o: \
 $(OBJ_DIR)/multilaterationalgorithm.o: \
 	$(SRC_DIR)/positioningalgorithm.hh \
 	$(OBJ_DIR)/minmax.o \
-	$(OBJ_DIR)/mobile.o
+	$(OBJ_DIR)/mobile.o \
+	$(OBJ_DIR)/configuration.o \
+	$(OBJ_DIR)/posexcept.o
 $(OBJ_DIR)/cartographyalgorithm.o: \
 	$(SRC_DIR)/positioningalgorithm.hh \
 	$(OBJ_DIR)/referencepoint.o
diff --git a/owlps-positioning/TODO b/owlps-positioning/TODO
index edec94a..f61eaa2 100644
--- a/owlps-positioning/TODO
+++ b/owlps-positioning/TODO
@@ -1,20 +1,24 @@
 
+- Multithread algorithm calls.
+
 - Write a class for Request::type?
    CalibrationRequest::direction uses a dedicated class Direction, why
    not Request::type? That would simplify writing of the type to
    streams (no need to cast each time anymore).
 
-- Interface utilisateur
-   ° Pour plus de souplesse, comparer les chaînes sans tenir compte de
-   la casse.
+- User interface
+   ° Case-insensitive string comparison (for algorithm names, etc.).
+   ° Use a prefix for configuration files (search for config files set
+   with relative path in owlps-positioning.cfg in the same directory).
 
-- Tests unitaires
+- Unit tests
    ° Update tests (currently unmaintained).
-   ° Finir le test de InputDataReader.
-   ° Finir le test de Input.
-   ° Finir le test de Output.
-   ° Finir le test de Positioning.
-   ° Tester InterlinkNetworks::compute() ?
+   ° Unfinished tests:
+   .   InputDataReader
+   .   Input
+   .   Output
+   .   Positioning
+   ° Test InterlinkNetworks::compute() ?
 
 - Revoir le diagramme UML
    ° Associations : devraient êtres représentées par des attributs
@@ -33,7 +37,6 @@
 
 - MinMax
    ° Différencier le pas pour X, Y et Z ?
-   ° Régler le start & stop dans MultilaterationAlgorithm.
 
 - Renommages de membres
    ° InputMedium :
diff --git a/owlps-positioning/cfg/listerers.csv b/owlps-positioning/cfg/listerers.csv
new file mode 100644
index 0000000..f773f5d
--- /dev/null
+++ b/owlps-positioning/cfg/listerers.csv
@@ -0,0 +1,10 @@
+# Listeners' physical description file.
+#
+# Each line follows this format:
+#   MAC address;X;Y;Z;Channel (Hz);Antenna gain (dBi);Trx power (dBm)
+#
+# Blank lines are ignored. Commented lines must have a sharp (#) as
+# their FIRST character.
+
+# Example listener:
+#00:11:22:33:44:55;4;0.5;7.95;2417000000;5.0;20.0
diff --git a/owlps-positioning/cfg/minipc.csv b/owlps-positioning/cfg/minipc.csv
deleted file mode 100644
index 0422be5..0000000
--- a/owlps-positioning/cfg/minipc.csv
+++ /dev/null
@@ -1,20 +0,0 @@
-# Fichier de configuration pour les AP.
-# Chaque ligne est de la forme :
-#   MAC;X;Y;Z;Fréquence d'émission (Hz);Gain d'antenne (dBi);Puissance d'émission (dBm)
-# Les lignes vides ou commençant par un # sont ignorées. Les
-# commentaires doivent obligatoirement être en début de ligne.
-
-# mini5 (Laseldi) 
-00:13:CE:95:E1:6F;4.93;25.81;3.55;2417000000;5.0;20.0
-
-# mini6 (Laurent / Wassim)
-00:13:CE:95:DE:7E;4.83;10.88;3.78;2417000000;5.0;20.0
-
-# mini4 (Incubateur)
-00:13:CE:97:78:79;20.05;28.31;3.74;2417000000;5.0;20.0
-
-# mini3 (Dominique)
-00:13:CE:8F:77:43;4.13;7.085;0.80;2417000000;5.0;20.0
-
-# mini1 (Adrien)
-00:13:CE:8F:78:D9;5.74;30.35;2.04;2417000000;5.0;20.0
diff --git a/owlps-positioning/cfg/owlps-positioning.cfg b/owlps-positioning/cfg/owlps-positioning.cfg
index 02f555e..5ad76b5 100644
--- a/owlps-positioning/cfg/owlps-positioning.cfg
+++ b/owlps-positioning/cfg/owlps-positioning.cfg
@@ -1,15 +1,21 @@
 # Sample configuration file for OWLPS Positioning
 
-# Miscellaneous options
+# [Miscellaneous options]
+
 #flush-output-files = true
 
 [data-input]
 
-#ap-medium = CSV
-ap-csv-file = cfg/access_points.csv
+# Description of the machines running the listeners.
+ap-medium = CSV
+ap-csv-file = cfg/listeners.csv
 
-topology-medium = CSV
-areas-csv-file = cfg/topo.csv
+# Description of deployment area topology.
+# You probably don't need a full description of the topology, see the
+# topology example file for details.
+# Uncomment the following line to activate the topology reading.
+#topology-medium = CSV
+areas-csv-file = cfg/topology.csv
 waypoints-csv-file = cfg/waypoints.csv
 
 #reference-points-medium = CSV
@@ -32,10 +38,24 @@ csv-file = /tmp/owlps-positioning.log
 
 [positioning]
 
+# Uncomment lines to activate one or more algorithm.
+#algorithm = Real
+#algorithm = InterlinkNetworks
+#algorithm = FBCM
+#algorithm = RADAR
 #algorithm = FRBHMBasic
 
+# Start and stop coordinates for the MinMax multilateration method.
+# Since MinMax is currently the only multilateration method implemented
+# in OwlPS, you should define these parameters if you use any of the
+# multilateration-based algorithms (InterlinkNetworks, FBCM, FRBHM).
+# They are declared as strings (X;Y;Z). Do not quote!
+#minmax-start = -2;-2;0
+#minmax-stop = 20;30;6
+
 [output]
 
+# This is the default output if none is specified.
 #medium = Terminal
 
 #medium = CSV
diff --git a/owlps-positioning/cfg/topo.csv b/owlps-positioning/cfg/topo.csv
deleted file mode 100644
index 2c606d2..0000000
--- a/owlps-positioning/cfg/topo.csv
+++ /dev/null
@@ -1,48 +0,0 @@
-# Liste des bâtiments et de leurs zones homogènes (pièces).
-# Chaque ligne définit une zone, de la forme :
-#   Nom du bâtiment;Nom de la pièce;X1;Y1;X2;Y2;Z1;Z2
-
-
-### Rez-de-chaussée ###
-#
-Numerica;0140;1.00;7.28;6.05;3.70;0.00;2.99
-Numerica;0130;1.00;10.88;6.05;7.28;0.00;2.99
-Numerica;0120;1.00;14.48;6.05;10.88;0.00;2.99
-Numerica;0110;1.00;18.12;6.05;14.48;0.00;2.99
-Numerica;0100;1.00;21.66;6.05;18.12;0.00;2.99
-Numerica;0090;1.00;25.32;6.05;21.66;0.00;2.99
-Numerica;0080;1.00;29.00;6.05;25.32;0.00;2.99
-Numerica;0070;1.00;32.00;6.05;29.00;0.00;2.99
-Numerica;WC N0;8.20;5.30;10.00;0.50;0.00;2.99
-Numerica;0085;8.20;9.00;10.00;5.30;0.00;2.99
-Numerica;0075;8.20;10.88;10.00;9.00;0.00;2.99
-Numerica;Palier N0;5.00;3.70;8.20;0.50;0.00;2.99
-Numerica;Couloir N0 A;6.05;30.00;8.20;3.70;0.00;2.99
-Numerica;Couloir N0 B;8.20;16.50;10.00;10.88;0.00;2.99
-Numerica;Couloir N0 C;8.20;24.80;10.00;22.60;0.00;2.99
-
-
-### Escaliers N0 / N1 ###
-#
-# TODO : affiner la hauteur, etc.
-Numerica;Escalier N0-N1 A;8.20;22.60;10.00;16.50;0.00;6.00
-Numerica;Escalier N0-N1 B1;2.50;2.00;5.00;0.50;0.00;6.00
-Numerica;Escalier N0-N1 B palier;1.00;3.70;2.50;0.50;1.50;6.00
-Numerica;Escalier N0-N1 B2;2.50;3.70;5.00;2.00;1.50;6.00
-
-
-### Premier étage ###
-#
-Numerica;1100;1.00;7.28;6.05;3.70;3.00;6.00
-Numerica;0190;1.00;10.88;6.05;7.28;3.00;6.00
-Numerica;0180;1.00;14.48;6.05;10.88;3.00;6.00
-Numerica;1070;1.00;18.12;6.05;14.48;3.00;6.00
-Numerica;1060;1.00;25.32;6.05;18.12;3.00;6.00
-Numerica;1050;1.00;31.40;6.05;25.32;3.00;6.00
-Numerica;WC N1;8.20;9.00;10.00;0.50;3.00;6.00
-Numerica;1105;8.20;10.88;10.00;9.00;3.00;6.00
-Numerica;1095;8.20;29.30;10.00;24.80;3.00;6.00
-Numerica;Palier N1;5.00;3.70;8.20;0.50;3.00;6.00
-Numerica;Couloir N1 A;6.05;29.50;8.20;3.70;3.00;6.00
-Numerica;Couloir N1 B;8.20;16.50;10.00;10.88;3.00;6.00
-Numerica;Couloir N1 C;8.20;24.80;10.00;22.60;3.00;6.00
diff --git a/owlps-positioning/cfg/topology.csv b/owlps-positioning/cfg/topology.csv
new file mode 100644
index 0000000..9eac23f
--- /dev/null
+++ b/owlps-positioning/cfg/topology.csv
@@ -0,0 +1,36 @@
+# Description of deployment area topology (rooms).
+#
+# IMPORTANT:
+#   You need a precise topology description if you use algorithms that
+#   handle it. Since none of them are currently implemented, you
+#   probably can save a lot of time by skipping the topology (and
+#   waypoints) description.
+#
+# ALSO IMPORTANT (EVEN IF YOU DON'T DESCRIBE THE TOPOLOGY):
+#   If you use the MinMax multilateration method, you should provide
+#   minmax-start and minmax-stop parameters that match the deployment
+#   area. That is, the cuboid formed by these two points should include
+#   the whole deployment area.
+#
+# This file lists the buildings and their "homogeneous areas" (rooms).
+#
+# Each line defines an area, using the following format:
+#   Building name;Room name;X1;Y1;Z1;X2;Y2;Z2
+
+
+### First floor ###
+#
+#My Building;Entrance;1.00;7.28;6.05;3.70;0.00;2.99
+#My Building;Corridor A;6.05;30.00;8.20;3.70;0.00;2.99
+
+
+### 1st/2nd floor staircase ###
+#
+#My Building;Staircase;2.50;2.00;0.00;5.00;0.50;6.00
+#My Building;Staircase landing;1.00;3.70;1.50;2.50;0.50;6.00
+#My Building;Staircase;2.50;3.70;1.50;5.00;2.00;6.00
+
+
+### Second floor ###
+#
+#My Building;My desk;1.00;7.28;6.05;3.70;3.00;6.00
diff --git a/owlps-positioning/cfg/waypoints.csv b/owlps-positioning/cfg/waypoints.csv
index a53bc24..42f8a09 100644
--- a/owlps-positioning/cfg/waypoints.csv
+++ b/owlps-positioning/cfg/waypoints.csv
@@ -1,124 +1,19 @@
-# Liste des points de passage.
-# Chaque ligne définit les trois coordonnées d'un point, de la forme :
-#   X;Y;Z;Nom du bâtiment 1;…;Nom du bâtiment n
-# Chaque point doit appartenir au moins à un bâtiment.
+# Description of deployment area topology (waypoints).
+#
+# IMPORTANT:
+#   Maybe you don't want to define any waypoint. Please read the
+#   topology example file before losing time.
+#
+# This file lists the waypoints linking the areas defined in the
+# topology file (doors, etc.).
+#
+# Each line defines a waypoint, using the following format:
+#   X;Y;Z;Building1 name;…;BuildingN name
+# Each point must belong to at least one building.
+#
+# Note: for the non-convex rooms (which are defined by several areas in
+# the topology file), and for wide gates, you should define one waypoint
+# each 1m or 1.5m.
 
-# Note : pour les zones appartenant à la même pièce non-convexe (ex :
-# Couloir N0 A et Couloir N0 B), on définit un point tous les 1,50 m.
-# Idem pour les portes très larges.
-
-### Rez-de-chaussée ###
-
-# 0140
-6.05;6.50;0.00;Numerica
-
-# 0130
-6.05;7.50;0.00;Numerica
-
-# 0120
-6.05;13.50;0.00;Numerica
-
-# 0130 / 0120
-3.00;10.88;0.00;Numerica
-
-# 0110
-6.05;14.50;0.00;Numerica
-
-# 0100
-6.05;21.00;0.00;Numerica
-
-# 0090
-6.05;22.25;0.00;Numerica
-
-# 0080
-6.05;28.50;0.00;Numerica
-
-# 0070
-6.05;29.50;0.00;Numerica
-
-# WC N0
-8.20;5.00;0.00;Numerica
-
-# 0085
-8.20;8.50;0.00;Numerica
-
-# 0075
-8.20;9.50;0.00;Numerica
-
-# Couloir N0 A / B
-8.20;11.50;0.00;Numerica
-8.20;13.00;0.00;Numerica
-8.20;14.50;0.00;Numerica
-8.20;16.00;0.00;Numerica
-
-# Couloir N0 A / C
-8.20;23.70;0.00;Numerica
-
-# Palier N0
-7.50;3.70;0.00;Numerica
-
-
-### Escaliers N0 / N1 ###
-
-# Couloir N0 C / Escalier NO-N1 A
-8.95;22.60;0.00;Numerica
-
-# Escalier NO-N1 A / Couloir N1 B
-8.95;16.50;3.00;Numerica
-
-# Palier NO / Escalier N0-N1 B1
-5.00;1.25;0.00;Numerica
-
-# Escalier N0-N1 B1 / Escalier N0-N1 B palier
-2.50;1.25;1.50;Numerica
-
-# Escalier N0-N1 B palier / Escalier N0-N1 B2
-2.50;2.75;1.50;Numerica
-
-# Escalier N0-N1 B2 / Palier N1
-5.00;2.75;3.00;Numerica
-
-
-### Premier étage ###
-
-# 1100
-6.05;6.50;3.00;Numerica
-
-# 0190
-6.05;7.50;3.00;Numerica
-
-# 0180
-6.05;13.50;3.00;Numerica
-
-# 0190 / 0180
-3.00;10.88;3.00;Numerica
-
-# 1070
-6.05;14.50;3.00;Numerica
-
-# 1060
-6.05;21.00;3.00;Numerica
-
-# 1050
-6.05;27.75;3.00;Numerica
-
-# WC N1
-8.20;5.00;3.00;Numerica
-
-# 1105
-8.20;9.50;3.00;Numerica
-
-# 1095
-8.20;26.00;3.00;Numerica
-
-# Couloir N1 A / B
-8.20;11.50;3.00;Numerica
-8.20;13.00;3.00;Numerica
-8.20;14.50;3.00;Numerica
-8.20;16.00;3.00;Numerica
-
-# Couloir N1 A / C
-8.20;23.70;3.00;Numerica
-
-# Palier N1
-7.50;3.70;3.00;Numerica
+# Example waypoint:
+#1.5;4;0;My Building
diff --git a/owlps-positioning/csv/README b/owlps-positioning/csv/README
index 2a16689..56bc5e2 100644
--- a/owlps-positioning/csv/README
+++ b/owlps-positioning/csv/README
@@ -1,5 +1,5 @@
-Ce répertoire sert à stocker les fichiers d'entrée de GuiNuMo-server.
-Vous pouvez trouver des fichiers d'exemple sur :
+This directory is for storing the owlps-positioning input files.
+You can find example data files at:
 	http://pif.pu-pm.univ-fcomte.fr/~mcyprian/mesures/
 
--- Vous pouvez supprimer ce fichier sans danger. --
+-- You can safely delete this file. --
diff --git a/owlps-positioning/log/README b/owlps-positioning/log/README
index 36d2b8f..083529a 100644
--- a/owlps-positioning/log/README
+++ b/owlps-positioning/log/README
@@ -1,3 +1,3 @@
-Ce répertoire sert à stocker les fichiers de destination de GuiNuMo-server.
+This directory is for storing the owlps-positioning output files.
 
--- Vous pouvez supprimer ce fichier sans danger. --
+-- You can safely delete this file. --
diff --git a/owlps-positioning/src/accesspoint.hh b/owlps-positioning/src/accesspoint.hh
index d5fc517..5919766 100644
--- a/owlps-positioning/src/accesspoint.hh
+++ b/owlps-positioning/src/accesspoint.hh
@@ -127,7 +127,7 @@ inline void AccessPoint::set_channel(const unsigned int channel)
  * control is done, so you should pass a correct value.
  *
  * Note that set_channel() is more secure because a wrong channel
- * number will cause #frequency to be nullified.
+ * number will cause #frequency to be set to zero.
  */
 inline void AccessPoint::set_frequency(const unsigned long _frequency)
 {
diff --git a/owlps-positioning/src/accesspointsreadercsv.cc b/owlps-positioning/src/accesspointsreadercsv.cc
index b6c7508..a33aa52 100644
--- a/owlps-positioning/src/accesspointsreadercsv.cc
+++ b/owlps-positioning/src/accesspointsreadercsv.cc
@@ -38,7 +38,7 @@ void AccessPointsReaderCSV::process_access_point_line()
   if (! file.read_point3d(coord))
     throw malformed_input_data("Cannot read access point coordinates!") ;
 
-  long frequency ;
+  unsigned long frequency ;
   if (! file.read_field(frequency))
     throw malformed_input_data("Cannot read access point frequency!") ;
 
diff --git a/owlps-positioning/src/area.cc b/owlps-positioning/src/area.cc
index e176b85..ce02aa7 100644
--- a/owlps-positioning/src/area.cc
+++ b/owlps-positioning/src/area.cc
@@ -83,7 +83,7 @@ void Area::reorder_coordinates()
     }
 
   // First point is South-West
-  // (or other cases such as null coordinates)
+  // (or other cases such as coordinates equal to zero)
   else
     {
       // We swap nothing
diff --git a/owlps-positioning/src/calibrationrequest.cc b/owlps-positioning/src/calibrationrequest.cc
index bfd1bb4..cb33471 100644
--- a/owlps-positioning/src/calibrationrequest.cc
+++ b/owlps-positioning/src/calibrationrequest.cc
@@ -6,7 +6,8 @@
 /* *** Constructors *** */
 
 
-CalibrationRequest::CalibrationRequest(uint_fast8_t _type):
+CalibrationRequest::
+CalibrationRequest(uint_fast8_t _type = OWL_REQUEST_AUTOCALIBRATION):
   reference_point(NULL), direction(Direction())
 {
   type = _type ;
@@ -16,8 +17,8 @@ CalibrationRequest::CalibrationRequest(uint_fast8_t _type):
 CalibrationRequest::
 CalibrationRequest(const Request &source,
                    ReferencePoint *_reference_point = NULL,
-                   const Direction &_direction,
-                   uint_fast8_t _type):
+                   const Direction &_direction = Direction(),
+                   uint_fast8_t _type = OWL_REQUEST_AUTOCALIBRATION):
   Request(source), reference_point(_reference_point),
   direction(_direction)
 {
diff --git a/owlps-positioning/src/calibrationrequest.hh b/owlps-positioning/src/calibrationrequest.hh
index 4d85529..d0a26eb 100644
--- a/owlps-positioning/src/calibrationrequest.hh
+++ b/owlps-positioning/src/calibrationrequest.hh
@@ -16,14 +16,16 @@ protected:
   Direction direction ;
 
 public:
-  CalibrationRequest(uint_fast8_t _type = OWL_REQUEST_AUTOCALIBRATION) ;
+  CalibrationRequest(uint_fast8_t _type) ;
+
   CalibrationRequest(const CalibrationRequest &source):
     Request(source), reference_point(source.reference_point),
     direction(source.direction) {}
+
   CalibrationRequest(const Request &source,
                      ReferencePoint *_reference_point,
-                     const Direction &_direction = Direction(),
-                     uint_fast8_t _type = OWL_REQUEST_AUTOCALIBRATION) ;
+                     const Direction &_direction,
+                     uint_fast8_t _type) ;
 
   ~CalibrationRequest(void) {}
 
diff --git a/owlps-positioning/src/inputcsv.cc b/owlps-positioning/src/inputcsv.cc
index fc4a6ff..db5ebe6 100644
--- a/owlps-positioning/src/inputcsv.cc
+++ b/owlps-positioning/src/inputcsv.cc
@@ -10,6 +10,8 @@
 using namespace std ;
 using std::tr1::unordered_map ;
 
+#define DEBUG
+
 
 
 /* *** Operations *** */
@@ -39,18 +41,28 @@ const Request& InputCSV::get_next_request()
   // Read Mobile MAC field
   string mac_mobile ;
   if (! file.read_field(mac_mobile)) // Wrong number of fields
-    return *current_request ;
+    {
+#ifdef DEBUG
+      cerr << "InputCSV: cannot read mac_mobile.\n" ;
+#endif // DEBUG
+      return *current_request ;
+    }
   const Mobile &mobile = Stock::find_create_mobile(mac_mobile) ;
   current_request->set_mobile(&mobile) ;
 
   // Read request type
   uint8_t type ;
-  if (! file.read_field(type))
+  uint16_t type_r ;
+  if (! file.read_field(type_r))
     {
       // Wrong number of fields: blank current request
       current_request->clear() ;
+#ifdef DEBUG
+      cerr << "InputCSV: cannot read type.\n" ;
+#endif // DEBUG
       return *current_request ;
     }
+  type = type_r ;
   current_request->set_type(type) ;
 
   // Read Timestamp field
@@ -59,6 +71,9 @@ const Request& InputCSV::get_next_request()
     {
       // Wrong number of fields: blank current request
       current_request->clear() ;
+#ifdef DEBUG
+      cerr << "InputCSV: cannot read timestamp.\n" ;
+#endif // DEBUG
       return *current_request ;
     }
   current_request->set_time_sent(timestamp) ;
@@ -69,6 +84,9 @@ const Request& InputCSV::get_next_request()
     {
       // Wrong number of fields: blank current request
       current_request->clear() ;
+#ifdef DEBUG
+      cerr << "InputCSV: cannot read coordinates.\n" ;
+#endif // DEBUG
       return *current_request ;
     }
 
@@ -79,6 +97,9 @@ const Request& InputCSV::get_next_request()
     {
       // Wrong number of fields: blank current request
       current_request->clear() ;
+#ifdef DEBUG
+      cerr << "InputCSV: cannot read direction.\n" ;
+#endif // DEBUG
       return *current_request ;
     }
   if (direction_int != 0)
@@ -95,6 +116,9 @@ const Request& InputCSV::get_next_request()
         {
           // Wrong number of fields: blank current request
           current_request->clear() ;
+#ifdef DEBUG
+          cerr << "InputCSV: cannot read mac_ap.\n" ;
+#endif // DEBUG
           return *current_request ;
         }
       const AccessPoint &ap = Stock::find_create_ap(mac_ap) ;
@@ -108,15 +132,17 @@ const Request& InputCSV::get_next_request()
   if (type == OWL_REQUEST_CALIBRATION ||
       type == OWL_REQUEST_AUTOCALIBRATION)
     {
-      current_request_to_calibration_request(type) ;
-      CalibrationRequest *request =
-        static_cast<CalibrationRequest*>(current_request) ;
-      request->set_direction(direction) ;
       ReferencePoint position(pos) ;
       const ReferencePoint &reference_point =
         Stock::find_create_reference_point(position) ;
-      request->set_reference_point(&reference_point) ;
+      current_request_to_calibration_request(&reference_point,
+                                             direction, type) ;
     }
 
+  // We set the real coordinates (if found) only for non-calibration
+  // requests
+  else if (pos)
+    current_request->set_real_position(pos) ;
+
   return *current_request ;
 }
diff --git a/owlps-positioning/src/inputdatareader.cc b/owlps-positioning/src/inputdatareader.cc
index 4ca8062..cec622c 100644
--- a/owlps-positioning/src/inputdatareader.cc
+++ b/owlps-positioning/src/inputdatareader.cc
@@ -175,12 +175,12 @@ void InputDataReader::read_from_reference_points_media()
     {
       while (! (*i)->eof())
         {
-          Request &request =
-            const_cast<Request&>((*i)->get_next_request()) ;
+          const Request &request = (*i)->get_next_request() ;
           if (! request)
             continue ;
           CalibrationRequest *calibration_request =
-            dynamic_cast<CalibrationRequest*>(&request) ;
+            dynamic_cast<CalibrationRequest*>(
+              const_cast<Request*>(&request)) ;
 
           if (calibration_request == NULL)
             cerr << "Warning! Invalid calibration request at line "
diff --git a/owlps-positioning/src/inputmedium.cc b/owlps-positioning/src/inputmedium.cc
index 4fa7d56..e424633 100644
--- a/owlps-positioning/src/inputmedium.cc
+++ b/owlps-positioning/src/inputmedium.cc
@@ -24,18 +24,27 @@ InputMedium::~InputMedium()
 
 
 void InputMedium::
-current_request_to_calibration_request(uint_fast8_t request_type)
+current_request_to_calibration_request(
+  const ReferencePoint *const reference_point,
+  const Direction &direction,
+  const uint_fast8_t request_type)
 {
-  if (dynamic_cast<CalibrationRequest*>(current_request) != NULL)
+  CalibrationRequest *calibration_request =
+    dynamic_cast<CalibrationRequest*>(current_request) ;
+  if (calibration_request != NULL)
     {
-      current_request->set_type(request_type) ;
+      calibration_request->set_reference_point(reference_point) ;
+      calibration_request->set_direction(direction) ;
+      calibration_request->set_type(request_type) ;
       return ;
     }
 
   Request *tmp = current_request ;
   current_request = NULL ;
-  current_request = new CalibrationRequest(*tmp) ;
-  current_request->set_type(request_type) ;
+  current_request =
+    new CalibrationRequest(*tmp,
+                           const_cast<ReferencePoint*>(reference_point),
+                           direction, request_type) ;
   delete tmp ;
 }
 
diff --git a/owlps-positioning/src/inputmedium.hh b/owlps-positioning/src/inputmedium.hh
index a08d26c..c4a7571 100644
--- a/owlps-positioning/src/inputmedium.hh
+++ b/owlps-positioning/src/inputmedium.hh
@@ -1,6 +1,9 @@
 #ifndef _OWLPS_POSITIONING_INPUTMEDIUM_HH_
 #define _OWLPS_POSITIONING_INPUTMEDIUM_HH_
 
+class ReferencePoint ;
+class Direction ;
+
 #include "request.hh"
 
 /// Super class of all input media
@@ -51,7 +54,9 @@ public:
 
   /// Converts #current_request into a CalibrationRequest
   void current_request_to_calibration_request(
-    uint_fast8_t request_type = OWL_REQUEST_CALIBRATION) ;
+    const ReferencePoint *const reference_point,
+    const Direction &direction,
+    uint_fast8_t request_type) ;
   /// Clears (reallocates to Request if needed) #current_request
   void clear_current_request(void) ;
 
diff --git a/owlps-positioning/src/inputudpsocket.cc b/owlps-positioning/src/inputudpsocket.cc
index d2028bf..2776542 100644
--- a/owlps-positioning/src/inputudpsocket.cc
+++ b/owlps-positioning/src/inputudpsocket.cc
@@ -144,18 +144,25 @@ const Request& InputUDPSocket::get_next_request()
   if (request.type == OWL_REQUEST_CALIBRATION ||
       request.type == OWL_REQUEST_AUTOCALIBRATION)
     {
-      current_request_to_calibration_request(request.type) ;
-      CalibrationRequest *calib_request =
-        static_cast<CalibrationRequest*>(current_request) ;
-
-      calib_request->set_direction(Direction(request.direction)) ;
-
       ReferencePoint position(owl_ntohf(request.x_position),
                               owl_ntohf(request.y_position),
                               owl_ntohf(request.z_position)) ;
       const ReferencePoint &reference_point =
         Stock::find_create_reference_point(position) ;
-      calib_request->set_reference_point(&reference_point) ;
+      current_request_to_calibration_request(&reference_point,
+                                             Direction(request.direction),
+                                             request.type) ;
+    }
+
+  // We set the real coordinates (if found) only for non-calibration
+  // requests
+  else
+    {
+      Point3D pos(owl_ntohf(request.x_position),
+                  owl_ntohf(request.y_position),
+                  owl_ntohf(request.z_position)) ;
+      if (pos)
+        current_request->set_real_position(pos) ;
     }
 
   return *current_request ;
diff --git a/owlps-positioning/src/multilaterationalgorithm.cc b/owlps-positioning/src/multilaterationalgorithm.cc
index 3dae101..85d5fba 100644
--- a/owlps-positioning/src/multilaterationalgorithm.cc
+++ b/owlps-positioning/src/multilaterationalgorithm.cc
@@ -1,6 +1,8 @@
 #include "multilaterationalgorithm.hh"
 #include "minmax.hh"
 #include "mobile.hh"
+#include "configuration.hh"
+#include "posexcept.hh"
 
 using namespace std ;
 using std::tr1::unordered_map ;
@@ -14,10 +16,20 @@ MultilaterationAlgorithm::MultilaterationAlgorithm():
   request(NULL)
 {
   // Will be changed when other multilateration methods will be
-  // implemented
-  multilateration_method = new MinMax(Point3D(-0.5, -0.5, 0),
-                                      Point3D(10, 31.5, 6)) ;
-  // FIXME: minmax start and stop
+  // implemented.
+
+  if (! Configuration::is_configured("positioning.minmax-start") ||
+      ! Configuration::is_configured("positioning.minmax-stop"))
+    throw missing_configuration(
+      "You want to use MinMax, but either positioning.minmax-start or"
+      " positioning.minmax-stop is not defined!") ;
+
+  Point3D minmax_start(
+    Configuration::string_value("positioning.minmax-start")) ;
+  Point3D minmax_stop(
+    Configuration::string_value("positioning.minmax-stop")) ;
+
+  multilateration_method = new MinMax(minmax_start, minmax_stop) ;
 }
 
 
diff --git a/owlps-positioning/src/point3d.cc b/owlps-positioning/src/point3d.cc
index aff35bf..e496f00 100644
--- a/owlps-positioning/src/point3d.cc
+++ b/owlps-positioning/src/point3d.cc
@@ -1,8 +1,33 @@
 #include "point3d.hh"
+#include "posexcept.hh"
 
 #include <sstream>
 #include <boost/functional/hash.hpp>
 
+using namespace std ;
+
+
+
+/* *** Constructors *** */
+
+
+Point3D::Point3D(const string &source)
+{
+  float pos[3] ;
+  istringstream iss(source) ;
+
+  for (int i = 0 ; i < 2 ; ++i)
+    {
+      iss >> pos[i] ;
+      if (iss.get() != ';')
+        throw malformed_input_data(
+          "Point3D(string): cannot extract coordinates!") ;
+    }
+  iss >> pos[2] ;
+
+  set_coordinates(pos) ;
+}
+
 
 
 /* *** Distance operations *** */
@@ -84,16 +109,29 @@ bool Point3D::operator<(const Point3D &source) const
 }
 
 
-Point3D::operator std::string(void) const
+Point3D::operator string(void) const
 {
-  std::ostringstream oss ;
+  ostringstream oss ;
   oss << *this ;
   return oss.str() ;
 }
 
 
+/**
+ * @return \em true if either #x, #y or #z is non-zero.
+ * @return \em false if #x, #y and #z are defined to 0.
+ */
+Point3D::operator bool(void) const
+{
+  return
+    x != 0 &&
+    y != 0 &&
+    z != 0 ;
+}
 
-std::ostream& operator<<(std::ostream &os, const Point3D &p)
+
+
+ostream& operator<<(ostream &os, const Point3D &p)
 {
   os << "(" << p.x << ";" << p.y << ";" << p.z << ")" ;
   return os ;
diff --git a/owlps-positioning/src/point3d.hh b/owlps-positioning/src/point3d.hh
index f3f5652..c820afd 100644
--- a/owlps-positioning/src/point3d.hh
+++ b/owlps-positioning/src/point3d.hh
@@ -1,6 +1,7 @@
 #ifndef _OWLPS_POSITIONING_POINT3D_HH_
 #define _OWLPS_POSITIONING_POINT3D_HH_
 
+#include <string>
 #include <ostream>
 #include <cmath>
 
@@ -22,6 +23,8 @@ public:
   Point3D(const float source[3]):
     x(source[0]), y(source[1]), z(source[2]) {}
 
+  Point3D(const std::string &source) ;
+
   virtual ~Point3D(void) {}
 
   /** @name Read accessors */
@@ -69,6 +72,7 @@ public:
   bool operator>(const Point3D &source) const ;
   bool operator<=(const Point3D &source) const ;
   bool operator>=(const Point3D &source) const ;
+  operator bool(void) const ;
   operator std::string(void) const ;
   //@}
 
diff --git a/owlps-positioning/src/positioning.cc b/owlps-positioning/src/positioning.cc
index 52844a2..38480e0 100644
--- a/owlps-positioning/src/positioning.cc
+++ b/owlps-positioning/src/positioning.cc
@@ -51,7 +51,11 @@ void Positioning::initialise_algorithms()
        i != algo_names.end() ; ++i)
     {
       if (*i == "Real")
-        algorithms.push_back(new RealPosition) ;
+        /* In order to compute the errors of the other algorithms,
+         * Real must be the first for each request, so we add it at
+         * the begining.
+         */
+        algorithms.insert(algorithms.begin(), new RealPosition) ;
 
       else if (*i == "FBCM")
         {
@@ -87,10 +91,23 @@ void Positioning::loop()
       if (! request)
         continue ;
 
+      Point3D real_position ;
+      bool compute_error = false ;
       ResultList results(&request) ;
       for (algo = algorithms.begin() ; algo != algorithms.end() ;
            ++algo)
-        results.add((*algo)->compute(request)) ;
+        {
+          Result res((*algo)->compute(request)) ;
+          if (compute_error)
+            res.compute_error(real_position) ;
+          else if ((*algo)->get_name() == "Real")
+            {
+              compute_error = true ;
+              real_position = res.get_position() ;
+            }
+          results.add(res) ;
+        }
+
       output.write(results) ;
     }
 }
diff --git a/owlps-positioning/src/positioningalgorithm.hh b/owlps-positioning/src/positioningalgorithm.hh
index daf8387..748cf54 100644
--- a/owlps-positioning/src/positioningalgorithm.hh
+++ b/owlps-positioning/src/positioningalgorithm.hh
@@ -16,7 +16,18 @@ public:
     name(_name) {}
   virtual ~PositioningAlgorithm(void) {}
 
+  const std::string& get_name(void) const ;
+
   virtual Result compute(const Request &request) = 0 ;
 } ;
 
+
+
+inline const std::string& PositioningAlgorithm::get_name() const
+{
+  return name ;
+}
+
+
+
 #endif // _OWLPS_POSITIONING_POSITIONINGALGORITHM_HH_
diff --git a/owlps-positioning/src/realposition.cc b/owlps-positioning/src/realposition.cc
index 98d7281..2de435f 100644
--- a/owlps-positioning/src/realposition.cc
+++ b/owlps-positioning/src/realposition.cc
@@ -6,16 +6,18 @@
 
 Result RealPosition::compute(const Request &request)
 {
+  const Point3D *coordinates = NULL ;
+
   const CalibrationRequest *calibration_request =
     dynamic_cast<const CalibrationRequest*>(&request) ;
 
   if (calibration_request != NULL)
-    {
-      Point3D *coordinates =
-        static_cast<Point3D*>(
-          calibration_request->get_reference_point()) ;
-      return Result(*coordinates, name) ;
-    }
+    coordinates = static_cast<Point3D*>(
+                    calibration_request->get_reference_point()) ;
+
+  coordinates = request.get_real_position() ;
+  if (coordinates)
+    return Result(*coordinates, name) ;
 
   return Result(name) ;
 }
diff --git a/owlps-positioning/src/realposition.hh b/owlps-positioning/src/realposition.hh
index 783d440..97dc42b 100644
--- a/owlps-positioning/src/realposition.hh
+++ b/owlps-positioning/src/realposition.hh
@@ -11,7 +11,7 @@
 class RealPosition: public PositioningAlgorithm
 {
 public:
-  RealPosition(void): PositioningAlgorithm("RealPosition") {}
+  RealPosition(void): PositioningAlgorithm("Real") {}
 
   Result compute(const Request &request) ;
 } ;
diff --git a/owlps-positioning/src/request.cc b/owlps-positioning/src/request.cc
index 4ef2dc4..ef3afdc 100644
--- a/owlps-positioning/src/request.cc
+++ b/owlps-positioning/src/request.cc
@@ -22,6 +22,25 @@ Request::~Request()
 /* *** Write accessors *** */
 
 
+inline void Request::clear_real_position()
+{
+  if (real_position)
+    {
+      delete real_position ;
+      real_position = NULL ;
+    }
+}
+
+
+void Request::set_real_position(const Point3D &_real_position)
+{
+  if (real_position)
+    *real_position = _real_position ;
+  else
+    real_position = new Point3D(_real_position) ;
+}
+
+
 /// Reinitialises all attributes
 /**
  * - #mobile is NULLified, but the value it pointed to is not deleted.
@@ -34,6 +53,7 @@ void Request::clear()
   mobile = NULL ;
   time_sent.clear() ;
   measurements.clear() ;
+  clear_real_position() ;
 }
 
 
@@ -51,6 +71,10 @@ const Request& Request::operator=(const Request &source)
   time_sent = source.time_sent ;
   measurements = source.measurements ;
 
+  clear_real_position() ;
+  if (source.real_position)
+    real_position = new Point3D(*source.real_position) ;
+
   return *this ;
 }
 
@@ -60,7 +84,13 @@ bool Request::operator==(const Request &source) const
   if (this == &source)
     return true ;
 
+  bool real_position_equal =
+    real_position &&
+    source.real_position &&
+    *real_position == *source.real_position ;
+
   return
+    real_position_equal &&
     type == source.type &&
     mobile == source.mobile &&
     time_sent == source.time_sent &&
@@ -72,8 +102,10 @@ bool Request::operator==(const Request &source) const
 ostream& operator<<(ostream &os, const Request &r)
 {
   // Timestamp
-  os
-      << "At " << r.time_sent << "; " ;
+  os << "At " << r.time_sent << "; " ;
+
+  if (r.real_position)
+    os << " Real coordinates : " << *r.real_position << "; " ;
 
   // MAC address
   os
@@ -88,9 +120,7 @@ ostream& operator<<(ostream &os, const Request &r)
   else
     for (unordered_map<string, Measurement>::const_iterator i
          = r.measurements.begin() ; i != r.measurements.end() ; ++i)
-      {
-        os << '\n' << i->first << ": " << i->second ;
-      }
+      os << '\n' << i->first << ": " << i->second ;
 
   return os ;
 }
@@ -107,8 +137,10 @@ size_t hash_value(const Request &source)
 
   boost::hash_combine(seed, source.type) ;
   boost::hash_combine(seed, source.time_sent) ;
-  if (source.mobile != NULL)
+  if (source.mobile)
     boost::hash_combine(seed, source.mobile->get_mac_addr()) ;
+  if (source.real_position)
+    boost::hash_combine(seed, source.real_position) ;
 
   return seed ;
 }
diff --git a/owlps-positioning/src/request.hh b/owlps-positioning/src/request.hh
index 59fb421..f057162 100644
--- a/owlps-positioning/src/request.hh
+++ b/owlps-positioning/src/request.hh
@@ -26,6 +26,11 @@ protected:
   /** Note that this is not a pointer list, values are actually stored.
       The \em string parameter is the MAC address of the AP. */
   std::tr1::unordered_map<std::string, Measurement> measurements ;
+  /// \brief Real coordinates of the request (normally unavailable for a
+  /// standard positioning request)
+  Point3D *real_position ;
+
+  void clear_real_position(void) ;
 
 public:
   Request(const Mobile *_mobile = NULL,
@@ -35,12 +40,12 @@ public:
             std::tr1::unordered_map<std::string, Measurement>()):
     type(OWL_REQUEST_UNDEFINED),
     mobile(const_cast<Mobile*>(_mobile)), time_sent(_time_sent),
-    measurements(_measurements) {}
+    measurements(_measurements), real_position(NULL) {}
 
   Request(const std::tr1::unordered_map<std::string, Measurement>
           &_measurements):
     type(OWL_REQUEST_UNDEFINED),
-    mobile(NULL), measurements(_measurements) {}
+    mobile(NULL), measurements(_measurements), real_position(NULL) {}
 
   Request(const Timestamp &_time_sent,
           const std::tr1::unordered_map<std::string, Measurement>
@@ -48,12 +53,12 @@ public:
             std::tr1::unordered_map<std::string, Measurement>()):
     type(OWL_REQUEST_UNDEFINED),
     mobile(NULL), time_sent(_time_sent),
-    measurements(_measurements) {}
+    measurements(_measurements), real_position(NULL) {}
 
   Request(const Request &source):
     type(source.type),
     mobile(source.mobile), time_sent(source.time_sent),
-    measurements(source.measurements) {}
+    measurements(source.measurements), real_position(NULL) {}
 
   virtual ~Request(void) ;
 
@@ -64,6 +69,7 @@ public:
   const Timestamp& get_time_sent(void) const ;
   const std::tr1::unordered_map<std::string, Measurement>&
   get_measurements(void) const ;
+  const Point3D* get_real_position(void) const ;
   //@}
 
   /** @name Write accessors */
@@ -73,6 +79,7 @@ public:
   void set_time_sent(const Timestamp &_time_sent) ;
   void set_measurements(const std::tr1::unordered_map
                         <std::string, Measurement> &_measurements) ;
+  void set_real_position(const Point3D &_real_position) ;
   void clear(void) ;
   //@}
 
@@ -122,6 +129,12 @@ Request::get_measurements(void) const
 }
 
 
+inline const Point3D* Request::get_real_position(void) const
+{
+  return real_position ;
+}
+
+
 
 /* *** Write accessors *** */
 
@@ -164,7 +177,8 @@ inline bool Request::operator!=(const Request &comp) const
 
 /**
  * @return \em false if the Request is empty.
- * @return \em true if at least one attribute is initialised.
+ * @return \em true if at least one attribute (other than #type) is
+ * initialised.
  */
 inline Request::operator bool() const
 {
diff --git a/owlps-positioning/src/result.cc b/owlps-positioning/src/result.cc
index 1173b0c..7645b3e 100644
--- a/owlps-positioning/src/result.cc
+++ b/owlps-positioning/src/result.cc
@@ -7,6 +7,28 @@ using namespace std ;
 
 
 
+/* *** Constructors *** */
+
+
+Result::Result(const Point3D &_position, const std::string &_algorithm,
+               const Point3D &real_position):
+  position(_position), algorithm(_algorithm)
+{
+  compute_error(real_position) ;
+}
+
+
+
+/* *** Write accessors *** */
+
+
+void Result::compute_error(const Point3D &real_position)
+{
+  error = position.distance(real_position) ;
+}
+
+
+
 /* *** Operators *** */
 
 
@@ -42,7 +64,9 @@ const string Result::to_csv() const
       << algorithm
       << ';' << position.get_x()
       << ';' << position.get_y()
-      << ';' << position.get_z() ;
+      << ';' << position.get_z()
+      << ';' << "Error"
+      << ';' << error ;
 
   return csv_line.str() ;
 }
@@ -54,5 +78,7 @@ std::ostream& operator<<(ostream &os, const Result &r)
   os
       << "The result of the algorithm " << r.algorithm
       << " is: " << r.position ;
+  if (r.error >= 0)
+    os << ", error = " << r.error << " m" ;
   return os ;
 }
diff --git a/owlps-positioning/src/result.hh b/owlps-positioning/src/result.hh
index ac7f223..5861633 100644
--- a/owlps-positioning/src/result.hh
+++ b/owlps-positioning/src/result.hh
@@ -9,20 +9,33 @@
 class Result
 {
 protected:
+  /// Computed coordinates of the mobile
   Point3D position ;
+  /// Algorithm used to compute the position
   std::string algorithm ;
+  /// Distance error between the real coordinates and the computed point
+  /** The error is set to -1 if the real coordinates are unknown. */
+  float error ;
 
 public:
   Result(const std::string &_algorithm = "UnknownAlgorithm"):
-    algorithm(_algorithm) {}
+    algorithm(_algorithm), error(-1) {}
   Result(const Point3D &_position, const std::string &_algorithm):
-    position(_position), algorithm(_algorithm) {}
+    position(_position), algorithm(_algorithm), error(-1) {}
+  Result(const Point3D &_position, const std::string &_algorithm,
+         const Point3D &real_position) ;
   ~Result(void) {}
 
   /** @name Read accessors */
   //@{
   const std::string& get_algorithm(void) const ;
   const Point3D& get_position(void) const ;
+  float get_error(void) const ;
+  //@}
+
+  /** @name Write accessors */
+  //@{
+  void compute_error(const Point3D &real_position) ;
   //@}
 
   /** @name Operators */
@@ -59,6 +72,12 @@ inline const Point3D& Result::get_position() const
 }
 
 
+inline float Result::get_error() const
+{
+  return error ;
+}
+
+
 
 /* *** Operators *** */
 
diff --git a/owlps-positioning/src/timestamp.hh b/owlps-positioning/src/timestamp.hh
index d1a8e5b..de2ae8e 100644
--- a/owlps-positioning/src/timestamp.hh
+++ b/owlps-positioning/src/timestamp.hh
@@ -228,7 +228,7 @@ inline bool Timestamp::operator>=(const uint64_t source) const
 
 inline Timestamp::operator bool() const
 {
-  return static_cast<uint64_t>(*this) > 0 ;
+  return timestamp.tv_sec > 0 || timestamp.tv_nsec > 0 ;
 }
 
 
diff --git a/owlps-positioning/src/userinterface.cc b/owlps-positioning/src/userinterface.cc
index 4e96d09..ed1c7e5 100644
--- a/owlps-positioning/src/userinterface.cc
+++ b/owlps-positioning/src/userinterface.cc
@@ -14,7 +14,8 @@ namespace po = boost::program_options ;
 
 /* *** Default value definitions *** */
 
-#define DEFAULT_CONFIG_FILE_NAME "cfg/owlps-positioning.cfg"
+#define DEFAULT_CONFIG_FILE_NAME \
+  "/usr/local/etc/owlps/owlps-positioning.cfg"
 
 
 
@@ -171,6 +172,12 @@ void UserInterface::fill_positioning_options()
    "Algorithms used to compute positions. You can specify \
 this option more than once (but at least once). Allowed: Real, FBCM, \
 FRBHMBasic, InterlinkNetworks, RADAR.")
+  ("positioning.minmax-start", po::value<string>(),
+   "Coordinates of the start point of the MinMax multilateration \
+method (string format: \"X;Y;Z\").")
+  ("positioning.minmax-stop", po::value<string>(),
+   "Coordinates of the stop point of the MinMax multilateration \
+method (string format: \"X;Y;Z\").")
   ;
 
   file_options->add(options) ;