diff --git a/conf/modules/geo_mag.xml b/conf/modules/geo_mag.xml
index d3df1e1c0a..c672d7ff96 100644
--- a/conf/modules/geo_mag.xml
+++ b/conf/modules/geo_mag.xml
@@ -3,8 +3,9 @@
 <module name="geo_mag" dir="geo_mag">
   <doc>
     <description>
-      Geo Mag modell
-      by Sergey Kruskowski
+      GeoMagnetic field vector.
+      Calculation of the normalized geomagnetic field vector (saved to ahrs_impl.mag_h) at startup using GPS fix.
+      Based on the WMM2010 model (http://www.ngdc.noaa.gov/geomag/models.shtml).
     </description>
   </doc>
   <header>
@@ -12,10 +13,9 @@
   </header>
   <init fun="geo_mag_init()"/>
   <periodic fun="geo_mag_periodic()" freq="1"/>
-  <event fun="geo_mag_event()"/><!---->
+  <event fun="geo_mag_event()"/>
   <makefile>
     <file name="geo_mag.c"/>
-    <define name="USE_GEO_MAG"/>
     <file name="pprz_geodetic_wmm2010.c" dir="math"/>
   </makefile>
 </module>
diff --git a/sw/airborne/modules/geo_mag/geo_mag.c b/sw/airborne/modules/geo_mag/geo_mag.c
index aa5f60a105..88fd068b69 100644
--- a/sw/airborne/modules/geo_mag/geo_mag.c
+++ b/sw/airborne/modules/geo_mag/geo_mag.c
@@ -21,8 +21,8 @@
 
 /**
  * @file modules/geo_mag/geo_mag.c
- * @brief Calculation of the Geomagnetic field vector based on current GPS fix.
- * This module based on the WMM2010 modell (http://www.ngdc.noaa.gov/geomag/models.shtml).
+ * @brief Calculation of the Geomagnetic field vector from current GPS fix.
+ * This module is based on the WMM2010 model (http://www.ngdc.noaa.gov/geomag/models.shtml).
  */
 
 #include "modules/geo_mag/geo_mag.h"
@@ -42,13 +42,13 @@ void geo_mag_init(void) {
 }
 
 void geo_mag_periodic(void) {
-  if(gps.fix == GPS_FIX_3D && !geo_mag_vect.ready && !autopilot_motors_on)
+  if (gps.fix == GPS_FIX_3D && !geo_mag_vect.ready && !autopilot_motors_on)
     geo_mag_calc_flag = TRUE;
 }
 
 void geo_mag_event(void) {
 
-  if(geo_mag_calc_flag) {
+  if (geo_mag_calc_flag) {
     double gha[MAXCOEFF]; // Geomag global variables
     int32_t nmax;
 
diff --git a/sw/airborne/modules/geo_mag/geo_mag.h b/sw/airborne/modules/geo_mag/geo_mag.h
index 14a4304616..b752d785e7 100644
--- a/sw/airborne/modules/geo_mag/geo_mag.h
+++ b/sw/airborne/modules/geo_mag/geo_mag.h
@@ -21,8 +21,8 @@
 
 /**
  * @file modules/geo_mag/geo_mag.h
- * @brief Calculation of the Geomagnetic field vector based on current GPS fix.
- * This module based on the WMM2010 modell (http://www.ngdc.noaa.gov/geomag/models.shtml).
+ * @brief Calculation of the Geomagnetic field vector from current GPS fix.
+ * This module is based on the WMM2010 model (http://www.ngdc.noaa.gov/geomag/models.shtml).
  */
 
 #ifndef GEO_MAG_H