diff --git a/iridiumtk/reassembler/mtpos.py b/iridiumtk/reassembler/mtpos.py
index f61ad7d..41ff46c 100644
--- a/iridiumtk/reassembler/mtpos.py
+++ b/iridiumtk/reassembler/mtpos.py
@@ -72,7 +72,7 @@ def consume(self, q):
 
         if time >= self.last_output + self.intvl:
             self.last_output = time
-            self.mt_pos = [x for x in self.mt_pos if x['ts'] > time - 60]
+            self.mt_pos = [x for x in self.mt_pos if x['ts'] > time - self.exptime]
 
             ofile=config.output
             if ofile is None: