diff --git a/conf/firmwares/subsystems/fixedwing/autopilot.makefile b/conf/firmwares/subsystems/fixedwing/autopilot.makefile
index bb7c3104d5..309581e472 100644
--- a/conf/firmwares/subsystems/fixedwing/autopilot.makefile
+++ b/conf/firmwares/subsystems/fixedwing/autopilot.makefile
@@ -70,7 +70,7 @@ endif
 PERIODIC_FREQUENCY ?= 60
 $(TARGET).CFLAGS += -DPERIODIC_FREQUENCY=$(PERIODIC_FREQUENCY)
 $(TARGET).srcs   += mcu_periph/sys_time.c $(SRC_ARCH)/mcu_periph/sys_time_arch.c
-$(TARGET).CFLAGS += -DUSE_SYS_TIME -DSYS_TIME_RESOLUTION='(1./$(PERIODIC_FREQUENCY).)'
+$(TARGET).CFLAGS += -DUSE_SYS_TIME
 
 #
 # InterMCU & Commands