diff --git a/apps.json b/apps.json
index e768c0dc6..385463fd7 100644
--- a/apps.json
+++ b/apps.json
@@ -361,7 +361,7 @@
   { "id": "gpsnav",
     "name": "GPS Navigation",
     "icon": "icon.png",
-    "version":"0.03",
+    "version":"0.04",
     "description": "Displays GPS Course and Speed, + Directions to waypoint and waypoint recording, now with waypoint editor",
     "tags": "tool,outdoors,gps",
     "readme": "README.md",
diff --git a/apps/gpsnav/ChangeLog b/apps/gpsnav/ChangeLog
index d28ad53ac..ee8b61d7b 100644
--- a/apps/gpsnav/ChangeLog
+++ b/apps/gpsnav/ChangeLog
@@ -1,4 +1,4 @@
 0.01: New App!
 0.02: Add SCREENACCESS interface
 0.03: Add Waypoint Editor
-
+0.04: Fix great circle formula
diff --git a/apps/gpsnav/app.js b/apps/gpsnav/app.js
index 1e70b0cd3..3bbc756b7 100644
--- a/apps/gpsnav/app.js
+++ b/apps/gpsnav/app.js
@@ -93,9 +93,8 @@ function bearing(a,b){
 }
 
 function distance(a,b){
-  var x = radians(a.lon-b.lon) * Math.cos(radians((a.lat+b.lat)/2));
-  var y = radians(b.lat-a.lat);
-  return Math.round(Math.sqrt(x*x + y*y) * 6371000);
+  var dsigma = Math.acos(Math.sin(radians(a.lat))*Math.sin(radians(b.lat))+Math.cos(radians(a.lat))*Math.cos(radians(b.lat))*Math.cos(radians(a.lon-b.lon)));
+  return Math.round(dsigma*6371000);
 }
 
 var selected = false;