diff --git a/sw/airborne/subsystems/nav.c b/sw/airborne/subsystems/nav.c
index b3d07a2815..e3cab5e156 100644
--- a/sw/airborne/subsystems/nav.c
+++ b/sw/airborne/subsystems/nav.c
@@ -139,7 +139,7 @@ void nav_circle_XY(float x, float y, float radius) {
     (dist2_center > Square(abs_radius + dist_carrot)
      || dist2_center < Square(abs_radius - dist_carrot)) ?
     0 :
-    atan((*stateGetHorizontalSpeedNorm_f())*(*stateGetHorizontalSpeedNorm_f()) / (GRAVITY*radius));
+    atan((*stateGetHorizontalSpeedNorm_f())*(*stateGetHorizontalSpeedNorm_f()) / (NAV_GRAVITY*radius));
 
   float carrot_angle = dist_carrot / abs_radius;
   carrot_angle = Min(carrot_angle, M_PI/4);
diff --git a/sw/airborne/subsystems/nav.h b/sw/airborne/subsystems/nav.h
index 14dd78a2ff..9bb7b544f0 100644
--- a/sw/airborne/subsystems/nav.h
+++ b/sw/airborne/subsystems/nav.h
@@ -41,7 +41,7 @@
 #include "subsystems/navigation/common_flight_plan.h"
 #include "subsystems/navigation/common_nav.h"
 
-#define GRAVITY 9.806
+#define NAV_GRAVITY 9.806
 #define Square(_x) ((_x)*(_x))
 #define DistanceSquare(p1_x, p1_y, p2_x, p2_y) (Square(p1_x-p2_x)+Square(p1_y-p2_y))