diff --git a/include/IMU_Processing.h b/include/IMU_Processing.h
index 4552b51c..ec170ad8 100644
--- a/include/IMU_Processing.h
+++ b/include/IMU_Processing.h
@@ -18,6 +18,7 @@ which is included as part of this source code package.
 #include <condition_variable>
 #include <nav_msgs/Odometry.h>
 #include <utils/so3_math.h>
+#include <fstream>
 
 const bool time_list(PointType &x,
                      PointType &y); //{return (x.curvature < y.curvature);};
@@ -87,4 +88,4 @@ class ImuProcess
   bool exposure_estimate_en = true;
 };
 typedef std::shared_ptr<ImuProcess> ImuProcessPtr;
-#endif
\ No newline at end of file
+#endif