diff --git a/tests/e2e/test_coord.py b/tests/e2e/test_coord.py
index 19345fa..8ae0eee 100644
--- a/tests/e2e/test_coord.py
+++ b/tests/e2e/test_coord.py
@@ -23,14 +23,14 @@ def test_ecef_north_pole():
     assert alt == pytest.approx(0.0, abs=1e-2)
 
 
-def test_ecef_known_point_munich():
-    # Munich, Germany: lat≈48.1351, lon≈11.5820, alt≈520 m
-    # ECEF from standard converter:
-    #   X ≈ 4177789.3, Y ≈ 855098.1, Z ≈ 4727807.9
+def test_ecef_known_point_near_munich():
+    # Input ECEF (4177789.3, 855098.1, 4727807.9) m — point near Munich, Germany.
+    # Reference geodetic (Heikkinen closed-form, cross-checked vs Bowring iterative):
+    #   lat≈48.14141°, lon≈11.56740°, alt≈570.75 m.
     lat, lon, alt = ecef_to_wgs84(4177789.3, 855098.1, 4727807.9)
-    assert lat == pytest.approx(48.1351, abs=1e-3)
-    assert lon == pytest.approx(11.5820, abs=1e-3)
-    assert alt == pytest.approx(520.0, abs=2.0)
+    assert lat == pytest.approx(48.14141, abs=1e-4)
+    assert lon == pytest.approx(11.56740, abs=1e-4)
+    assert alt == pytest.approx(570.75, abs=1.0)
 
 
 def test_ecef_vpair_sample_point():