Multiplicative Linearized Kalman Filter in quaternion formulation. Estimates the gyro bias and needs magnetometer to update all 3 axes. Not suitable for fixedwings! Suitable for rotorcraft. The magnetometer is used and needs to be well calibrated. Estimates attitude and heading. Does not use GPS.
Add to your firmware section: This example contains all possible configuration options, not all of them are mandatory!
<!DOCTYPE module SYSTEM "module.dtd">
<module name="ahrs_float_mlkf" dir="ahrs" task="estimation">
<doc>
<description>
AHRS using MLKF filter.
Multiplicative Linearized Kalman Filter in quaternion formulation.
Estimates the gyro bias and needs magnetometer to update all 3 axes.
Not suitable for fixedwings!
Suitable for rotorcraft. The magnetometer is used and needs to be well calibrated. Estimates attitude and heading. Does not use GPS.
</description>
<configure name="AHRS_ALIGNER_LED" value="1" description="LED number to indicate AHRS alignment, none to disable (default is board dependent)"/>
<define name="AHRS_MAG_UPDATE_ALL_AXES" value="FALSE|TRUE" description="Use magnetometer to update all axes and not only yaw"/>
<define name="AHRS_MLKF_IMU_ID" value="ABI_BROADCAST" description="ABI sender id of IMU to use"/>
<define name="AHRS_MLKF_MAG_ID" value="ABI_BROADCAST" description="ABI sender id of magnetometer to use"/>
</doc>
<settings>
<dl_settings>
<dl_settings NAME="AHRS">
<dl_setting var="ahrs_mlkf.mag_noise.x" min="0.0" step="0.02" max="1.0" module="modules/ahrs/ahrs_float_mlkf" shortname="mag_noise_x" param="AHRS_MAG_NOISE_X" type="float" persistent="true"/>
<dl_setting var="ahrs_mlkf.mag_noise.y" min="0.0" step="0.02" max="1.0" module="modules/ahrs/ahrs_float_mlkf" shortname="mag_noise_y" param="AHRS_MAG_NOISE_Y" type="float" persistent="true"/>
<dl_setting var="ahrs_mlkf.mag_noise.z" min="0.0" step="0.02" max="1.0" module="modules/ahrs/ahrs_float_mlkf" shortname="mag_noise_z" param="AHRS_MAG_NOISE_Z" type="float" persistent="true"/>
</dl_settings>
</dl_settings>
</settings>
<dep>
<depends>ahrs_common,@imu,@mag</depends>
<provides>ahrs</provides>
</dep>
<makefile target="!sim|fbw">
<configure name="USE_MAGNETOMETER" default="1"/>
<define name="USE_MAGNETOMETER" cond="ifeq (,$(findstring $(USE_MAGNETOMETER),0 FALSE))"/>
<file name="ahrs_float_mlkf.c"/>
<file name="ahrs_float_mlkf_wrapper.c"/>
<test>
<define name="PRIMARY_AHRS" value="ahrs_mlkf"/>
<define name="AHRS_TYPE_H" value="modules/ahrs/ahrs_float_mlkf_wrapper.h" type="string"/>
</test>
<raw>
ifdef SECONDARY_AHRS
ifneq (,$(findstring $(SECONDARY_AHRS), mlkf float_mlkf))
# this is the secondary AHRS
$(TARGET).CFLAGS += -DAHRS_SECONDARY_TYPE_H=\"modules/ahrs/ahrs_float_mlkf_wrapper.h\"
$(TARGET).CFLAGS += -DSECONDARY_AHRS=ahrs_mlkf
else
# this is the primary AHRS
$(TARGET).CFLAGS += -DAHRS_TYPE_H=\"modules/ahrs/ahrs_float_mlkf_wrapper.h\"
$(TARGET).CFLAGS += -DPRIMARY_AHRS=ahrs_mlkf
endif
else
# plain old single AHRS usage
$(TARGET).CFLAGS += -DAHRS_TYPE_H=\"modules/ahrs/ahrs_float_mlkf_wrapper.h\"
endif
</raw>
</makefile>
</module>