diff --git a/sw/airborne/filters/low_pass_filter.h b/sw/airborne/filters/low_pass_filter.h
index 4d6d6a2bb3..92f0f476a0 100644
--- a/sw/airborne/filters/low_pass_filter.h
+++ b/sw/airborne/filters/low_pass_filter.h
@@ -28,6 +28,7 @@
 #define LOW_PASS_FILTER_H
 
 #include "std.h"
+#include "math/pprz_algebra_int.h"
 
 #define INT32_FILT_FRAC  8