AHRS using invariant filter. ahrs_common,@imu,@mag ahrs ifdef SECONDARY_AHRS ifneq (,$(findstring $(SECONDARY_AHRS), invariant float_invariant)) # this is the secondary AHRS $(TARGET).CFLAGS += -DAHRS_SECONDARY_TYPE_H=\"modules/ahrs/ahrs_float_invariant_wrapper.h\" $(TARGET).CFLAGS += -DSECONDARY_AHRS=ahrs_float_invariant else # this is the primary AHRS $(TARGET).CFLAGS += -DAHRS_TYPE_H=\"modules/ahrs/ahrs_float_invariant_wrapper.h\" $(TARGET).CFLAGS += -DPRIMARY_AHRS=ahrs_float_invariant endif else # plain old single AHRS usage $(TARGET).CFLAGS += -DAHRS_TYPE_H=\"modules/ahrs/ahrs_float_invariant_wrapper.h\" endif