diff --git a/utils/__init__.py b/utils/__init__.py
index 33908325b9d30d61587ca51cbdfc56fbaa48ab8b..620508fa14179b2f007b5a8a73c67fe1080792ea 100644
--- a/utils/__init__.py
+++ b/utils/__init__.py
@@ -66,5 +66,5 @@ def isoToGps(t):
         fracSec = float('0.' + sec_substr)
     else:
         fracSec = 0
-    posixTime = mktime(ISOTime.utctimetuple()) + fracSec 
+    posixTime = calendar.timegm(ISOTime.utctimetuple()) + fracSec 
     return int(round(posixToGpsTime(posixTime)))