diff --git a/python/adeunisrf.py b/python/adeunisrf.py
index 605694c..94cce45 100644
--- a/python/adeunisrf.py
+++ b/python/adeunisrf.py
@@ -21,27 +21,33 @@ import lorautil
 # sodaq: lat=46.9699219 lon=9.0391764
 # google:    46.969943,     9.038999
 
-known_devices = [ "0018B20000000C58", "0018B20000000C37", "0018B20000000C59", "0018B20000000CD0" ]
+log = logging.getLogger("adeunis")
+log.setLevel(logging.DEBUG)
 
+known_devices = [ "0018B20000000C58", "0018B20000000C37", "0018B20000000C59", "0018B20000000CD0" ]
 
 def get_gps(deveui, payload):
     res = []
     if not int(payload[0:2], 16) & (2**7):
         return res
 
-    lat_deg = float(payload[4:6])
-    lat_min = float(payload[6:8])
-    lat_sec = float(payload[8:10])
-    lat_frac_sec = float(payload[10:11])
-    lat = lat_deg + lat_min/60.0 + lat_sec/3600.0 + lat_frac_sec/36000.0
+    try:
+        lat_deg = float(payload[4:6])
+        lat_min = float(payload[6:8])
+        lat_sec = float(payload[8:10])
+        lat_frac_sec = float(payload[10:11])
+        lat = lat_deg + lat_min/60.0 + lat_sec/3600.0 + lat_frac_sec/36000.0
 
-    long_deg = float(payload[12:15])
-    long_min = float(payload[15:17])
-    long_sec = float(payload[17:19])
-    long_frac_sec = float(payload[19:20])
-    long = long_deg + long_min/60.0 + long_sec/3600 + long_frac_sec/36000.0
+        long_deg = float(payload[12:15])
+        long_min = float(payload[15:17])
+        long_sec = float(payload[17:19])
+        long_frac_sec = float(payload[19:20])
+        long = long_deg + long_min/60.0 + long_sec/3600 + long_frac_sec/36000.0
 
-    pos = ":lat={:.6f} long={:.6f}".format(lat, long)
+        pos = ":lat={:.6f} long={:.6f}".format(lat, long)
+
+    except ValueError as e:
+        log.info("GPS decode error: {}:{} {}".format(deveui, payload, e))
 
     res = [ deveui + pos ]