diff --git a/sw/lib/python/pprz_msg/message.py b/sw/lib/python/pprz_msg/message.py
index 1e2d4ca1fc0..c37bfd3a5cc 100644
--- a/sw/lib/python/pprz_msg/message.py
+++ b/sw/lib/python/pprz_msg/message.py
@@ -8,6 +8,7 @@
 import json
 import struct
 from . import messages_xml_map
+# import messages_xml_map
 
 
 class PprzMessageError(Exception):
@@ -33,6 +34,7 @@ def __init__(self, class_name, msg):
             self._id = messages_xml_map.get_msg_id(class_name, msg)
         self._fieldnames = messages_xml_map.get_msg_fields(class_name, self._name)
         self._fieldtypes = messages_xml_map.get_msg_fieldtypes(class_name, self._id)
+        self._fieldcoefs = messages_xml_map.get_msg_fieldcoefs(class_name, self._id)
         self._fieldvalues = []
         # set empty values according to type
         for t in self._fieldtypes:
@@ -73,6 +75,11 @@ def fieldtypes(self):
         """Get list of field types."""
         return self._fieldtypes
 
+    @property
+    def fieldcoefs(self):
+        """Get list of field coefs."""
+        return self._fieldcoefs
+
     def fieldbintypes(self, t):
         """Get type and length for binary format"""
         data_types = {
diff --git a/sw/lib/python/pprz_msg/messages_xml_map.py b/sw/lib/python/pprz_msg/messages_xml_map.py
index 3d5ec2d37d5..14f716a506c 100755
--- a/sw/lib/python/pprz_msg/messages_xml_map.py
+++ b/sw/lib/python/pprz_msg/messages_xml_map.py
@@ -13,6 +13,7 @@
 
 message_dictionary = {}
 message_dictionary_types = {}
+message_dictionary_coefs = {}
 message_dictionary_id_name = {}
 message_dictionary_name_id = {}
 
@@ -39,6 +40,7 @@ def parse_messages(messages_file=''):
             message_dictionary_name_id[class_name] = {}
             message_dictionary[class_name] = {}
             message_dictionary_types[class_name] = {}
+            message_dictionary_coefs[class_name] = {}
         for the_message in the_class.xpath("message[@name]"):
             message_name = the_message.attrib['name']
             if 'id' in the_message.attrib:
@@ -56,11 +58,17 @@ def parse_messages(messages_file=''):
             # insert this message into our dictionary as a list with room for the fields
             message_dictionary[class_name][message_name] = []
             message_dictionary_types[class_name][message_id] = []
+            message_dictionary_coefs[class_name][message_id] = []
 
             for the_field in the_message.xpath('field[@name]'):
                 # for now, just save the field names -- in the future maybe expand this to save a struct?
                 message_dictionary[class_name][message_name].append(the_field.attrib['name'])
                 message_dictionary_types[class_name][message_id].append(the_field.attrib['type'])
+                try:
+                    message_dictionary_coefs[class_name][message_id].append(float(the_field.attrib['alt_unit_coef']))
+                except KeyError:
+                    # print("no such key")
+                    message_dictionary_coefs[class_name][message_id].append(1.)
 
 
 def get_msgs(msg_class):
@@ -121,6 +129,18 @@ def get_msg_fieldtypes(msg_class, msg_id):
         print("Error: msg_class %s not found." % msg_class)
     return []
 
+def get_msg_fieldcoefs(msg_class, msg_id):
+    if not message_dictionary:
+        parse_messages()
+    if msg_class in message_dictionary_coefs:
+        if msg_id in message_dictionary_coefs[msg_class]:
+            return message_dictionary_coefs[msg_class][msg_id]
+        else:
+            print("Error: message with ID %d not found in msg_class %s." % (msg_id, msg_class))
+    else:
+        print("Error: msg_class %s not found." % msg_class)
+    return []
+
 
 def test():
     import argparse