diff --git a/ogn/commands/dbutils.py b/ogn/commands/dbutils.py
index 070d7fc..99bfaf3 100644
--- a/ogn/commands/dbutils.py
+++ b/ogn/commands/dbutils.py
@@ -6,7 +6,7 @@ from sqlalchemy.sql import null
 from sqlalchemy.orm import sessionmaker
 
 from ogn.model import AircraftBeacon, ReceiverBeacon
-from ogn.utils import wgs84_to_sphere
+from ogn.utils import haversine_distance
 
 
 os.environ.setdefault('OGN_CONFIG_MODULE', 'config.default')
@@ -33,9 +33,16 @@ def update_receiver_childs(name):
                      AircraftBeacon.radius == null()))
 
     for aircraft_beacon in aircraft_beacons_query.all():
-        [radius, theta, phi] = wgs84_to_sphere(last_receiver_beacon,
-                                               aircraft_beacon)
-        aircraft_beacon.radius = radius
+        location0 = (last_receiver_beacon.latitude, last_receiver_beacon.longitude)
+        location1 = (aircraft_beacon.latitude, aircraft_beacon.longitude)
+        alt0 = last_receiver_beacon.altitude
+        alt1 = aircraft_beacon.altitude
+
+        (flat_distance, phi) = haversine_distance(location0, location1)
+        theta = atan2(alt1 - alt0, flat_distance) * 180 / pi
+        distance = sqrt(flat_distance**2 + (alt1 - alt0)**2)
+
+        aircraft_beacon.radius = distance
         aircraft_beacon.theta = theta
         aircraft_beacon.phi = phi
     session.commit()
diff --git a/ogn/utils.py b/ogn/utils.py
index 698ef68..a8f546d 100644
--- a/ogn/utils.py
+++ b/ogn/utils.py
@@ -62,22 +62,16 @@ def get_country_code(latitude, longitude):
     return country_code
 
 
-def wgs84_to_sphere(receiver_beacon, aircraft_beacon):
-    from math import pi, asin, sqrt, sin, cos, atan2
-    deg2rad = pi / 180
-    rad2deg = 180 / pi
+def haversine_distance(location0, location1):
+    from math import asin, sqrt, sin, cos, atan2, radians, degrees
 
-    lat1 = receiver_beacon.latitude * deg2rad
-    lon1 = receiver_beacon.longitude * deg2rad
-    alt1 = receiver_beacon.altitude
+    lat0 = radians(location0[0])
+    lon0 = radians(location0[1])
+    lat1 = radians(location1[0])
+    lon1 = radians(location1[1])
 
-    lat2 = aircraft_beacon.latitude * deg2rad
-    lon2 = aircraft_beacon.longitude * deg2rad
-    alt2 = aircraft_beacon.altitude
+    distance = 6366000 * 2 * asin(sqrt((sin((lat0 - lat1) / 2))**2 + cos(lat0) * cos(lat1) * (sin((lon0 - lon1) / 2))**2))
+    print(distance)
+    phi = degrees(atan2(sin(lon0 - lon1) * cos(lat1), cos(lat0) * sin(lat1) - sin(lat0) * cos(lat1) * cos(lon0 - lon1)))
 
-    distance = 6366000 * 2 * asin(sqrt((sin((lat1 - lat2) / 2))**2 + cos(lat1) * cos(lat2) * (sin((lon1 - lon2) / 2))**2))
-    theta = atan2(alt2 - alt1, distance) * rad2deg
-    phi = atan2(sin(lon1 - lon2) * cos(lat2), cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(lon1 - lon2)) * rad2deg
-
-    radius = sqrt(distance**2 + (alt2 - alt1)**2)
-    return radius, theta, phi
+    return distance, phi
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 8a18173..c722b67 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,7 +1,7 @@
 import unittest
 
-from ogn.utils import get_ddb, get_trackable, get_country_code, wgs84_to_sphere
-from ogn.model import AddressOrigin, Beacon
+from ogn.utils import get_ddb, get_trackable, get_country_code, haversine_distance
+from ogn.model import AddressOrigin
 
 
 class TestStringMethods(unittest.TestCase):
@@ -44,51 +44,27 @@ class TestStringMethods(unittest.TestCase):
         country_code = get_country_code(latitude, longitude)
         self.assertEqual(country_code, None)
 
-    def test_wgs84_to_sphere(self):
-        receiver_beacon = Beacon()
-        receiver_beacon.latitude = 0
-        receiver_beacon.longitude = 0
-        receiver_beacon.altitude = 0
-
+    def test_haversine_distance(self):
         # delta: one latitude degree
-        aircraft_beacon = Beacon()
-        aircraft_beacon.latitude = -1
-        aircraft_beacon.longitude = 0
-        aircraft_beacon.altitude = 0
-        [radius, theta, phi] = wgs84_to_sphere(receiver_beacon, aircraft_beacon)
-        self.assertAlmostEqual(radius, 60 * 1852, -2)
-        self.assertEqual(theta, 0)
+        location0 = (0, 0)
+        location1 = (-1, 0)
+
+        (distance, phi) = haversine_distance(location0, location1)
+        self.assertAlmostEqual(distance, 60 * 1852, -2)
         self.assertEqual(phi, 180)
 
         # delta: one longitude degree at the equator
-        aircraft_beacon.latitude = 0
-        aircraft_beacon.longitude = -1
-        aircraft_beacon.altitude = 0
-        [radius, theta, phi] = wgs84_to_sphere(receiver_beacon, aircraft_beacon)
-        self.assertAlmostEqual(radius, 60 * 1852, -2)
-        self.assertEqual(theta, 0)
+        location0 = (0, 0)
+        location1 = (0, -1)
+
+        (distance, phi) = haversine_distance(location0, location1)
+        self.assertAlmostEqual(distance, 60 * 1852, -2)
         self.assertEqual(phi, 90)
 
-        # delta: 1000m altitude
-        aircraft_beacon.latitude = 0
-        aircraft_beacon.longitude = 0
-        aircraft_beacon.altitude = 1000
-        [radius, theta, phi] = wgs84_to_sphere(receiver_beacon, aircraft_beacon)
-        self.assertAlmostEqual(radius, 1000, 3)
-        self.assertEqual(theta, 90)
-        self.assertEqual(phi, 0)
+        # delta: 29000m
+        location0 = (48.865, 9.2225)
+        location1 = (48.74435, 9.578)
 
-        # receiver
-        receiver_beacon.latitude = 48.865
-        receiver_beacon.longitude = 9.2225
-        receiver_beacon.altitude = 574
-
-        # aircraft beacon
-        aircraft_beacon.latitude = 48.74435
-        aircraft_beacon.longitude = 9.578
-        aircraft_beacon.altitude = 929
-
-        [radius, theta, phi] = wgs84_to_sphere(receiver_beacon, aircraft_beacon)
-        self.assertAlmostEqual(radius, 29265.6035812215, -1)
-        self.assertAlmostEqual(theta, 0.694979846308314, 5)
+        (distance, phi) = haversine_distance(location0, location1)
+        self.assertAlmostEqual(distance, 29265.6035812215, -1)
         self.assertAlmostEqual(phi, -117.1275408121, 5)