diff --git a/sw/airborne/sim/sys_time_hw.h b/sw/airborne/sim/sys_time_hw.h
index 6b1119d061..298203de36 100644
--- a/sw/airborne/sim/sys_time_hw.h
+++ b/sw/airborne/sim/sys_time_hw.h
@@ -4,10 +4,7 @@
 #include <unistd.h>
 
 #define SYS_TICS_OF_SEC(x) (x)
-#define SYS_TICS_OF_USEC(x) (x)
-#define SYS_TICS_OF_NSEC(x) (x)
 #define SIGNED_SYS_TICS_OF_SEC(x) (x)
-#define SIGNED_SYS_TICS_OF_USEC(x) (x)
 
 #define SEC_OF_SYS_TICS(st) (st)
 #define MSEC_OF_SYS_TICS(st) (st)