Unexpected heading acquired during navigation using AHRS GX5

[FLaiRobotics]

We are facing an issue while using the orientation data for inferring the absolute heading of an autonomous ground vehicle from an 3DM-GX5-AHRS IMU. As shown in the image below, when navigating concentric square paths we see odometry alternating acute and obtuse angles where there appears to be a missing transformation or incorrect parameter configuration causing unexpected heading calculations at the turns.

Raw magnetometer data from /mag and raw orientation datum from IMU data from /imu/data/orientation gave similar results. We have calibrated the IMU (also hard and soft iron) using SensorConnect.

When tested with a different 9DOF IMU, we were able to track a square shaped path.

Environment:

• Ubuntu 20.04 LTS
• Architecture: x86_64
• ROS Version: Noetic
• Sensor: 3DM-GX5-AHRS

Appreciate your support investigating this issue.

Best, Debjit Ghosh

Listed below are the contents of params.xml:

# Standalone example params file for GX3, GX4, GX/CX5, RQ1 and GQ7 series devices
# Note: Feature support is device-dependent and some of the following settings may have no affect on your device.
# Please consult your device's documentation for supported features

# ****************************************************************** 
# NOTE: This file is formatted to work with ROS and will not work if specified as the params_file argument in ROS2.
#       If you want to override parameters for ROS2, start with https://github.com/LORD-MicroStrain/microstrain_inertial/blob/ros2/microstrain_inertial_driver/config/empty.yml
# ****************************************************************** 

# ****************************************************************** 
# General Settings 
# ****************************************************************** 

# port is the main port that the device will communicate over. For all devices except the GQ7, this is the only available port.
# aux_port is only available for the GQ7 and is only needed when streaming RTCM corrections to the device from ROS, or if you want to publish NMEA sentences from this node
port        : "/dev/ttyUSB0"
aux_port    : "/dev/ttyACM1"
baudrate    : 115200
debug       : False
diagnostics : False

# If set to true, this will configure the requested baudrate on the device.
# Note that this will be set on both USB and serial, but will only actually affect the baudrate of a serial connection.
set_baud : False

# Frame IDs used in the different messages. By default these are set to arbitrary strings as not to interfere with other ROS services.
# For more information on common frame IDs, check out: https://www.ros.org/reps/rep-0105.html
#
# filter_frame_id and filter_child_frame_id are specifically useful as the node will also publish a transform to the /tf topic
# that contains the transform between these two frames. Many ROS tools such as RViz will use the /tf topic to display things like robot position.
imu_frame_id          : "robot_footprint"
gnss1_frame_id        : "gnss1_antenna_wgs84"
gnss2_frame_id        : "gnss2_antenna_wgs84"
filter_frame_id       : "robot_footprint"
filter_child_frame_id : "robot_footprint"
nmea_frame_id         : "nmea"

# Waits for a configurable amount of time until the device exists
# If poll_max_tries is set to -1 we will poll forever until the device exists
poll_port      : False
poll_rate_hz   : 1.0
poll_max_tries : 60

# Number of times to attempt to reconnect to the device if it disconnects while running
# If configure_after_reconnect is true, we will also reconfigure the device after we reconnect
#      NOTE: It is strongly recommended to configure after reconnect unless device_setup is set to false
#            as the device will likely initialize in a different state otherwise
reconnect_attempts : 0
configure_after_reconnect : True

# Controls if the driver outputs data with-respect-to ENU frame
#      false - position, velocity, and orientation are WRT the NED frame (native device frame)
#      true  - position, velocity, and orientation are WRT the ENU frame
use_enu_frame : True

# Controls if the driver-defined setup is sent to the device
#      false - The driver will ignore the settings below and use the device's current settings
#      true  - Overwrite the current device settings with those listed below
device_setup : True

# Controls if the driver-defined settings are saved
#      false - Do not save the settings
#      true  - Save the settings in the device's non-volatile memory
save_settings : False

# Controls if the driver uses the device generated timestamp (if available) for timestamping messages
#      false - Use PC received time for timestamping
#      true  - Use device generated timestamp
use_device_timestamp : False

# Controls if the driver uses ROS time for timestamping messages. Can be useful when running under simulation.
# NOTE: This can be used in conjunction with use_device_timestamp in which case, the device timestmap will be used for sensor_msgs/TimeReference messages, and ROS time will be used for all other messages
#       false - Use PC received time for timestamping
#       true  - Use ROS time for timestamping all non sensor_msgs/TimeReference messages
use_ros_time : False

# Controls if the driver creates a raw binary file
#      false - Do not create the file
#      true  - Create the file
#
#      Notes: 1) The filename will have the following format -
#                model_number "_" serial_number "_" datetime (year_month_day_hour_minute_sec) ".bin"
#                example: "3DM-GX5-45_6251.00001_20_12_01_01_01_01.bin"
#             2) This file is useful for getting support from the manufacturer
raw_file_enable : False

# (GQ7/CV7 only) Controls if the driver requests additional factory support data to be included in the raw data file
#      false - Do not request the additional data
#      true  - Request the additional channels (please see notes below!)
#
#      Notes: **We recommend only enabling this feature when specifically requested by Microstrain.**
#      
#      Including this feature increases communication bandwidth requirements significantly... for serial data connections
#      please ensure the baudrate is sufficient for the added data channels.     
raw_file_include_support_data : False

# The directory to store the raw data file (no trailing '/')
raw_file_directory : "/home/your_name"

# ****************************************************************** 
# IMU Settings 
# ****************************************************************** 
imu_data_rate : 100

# The speed at which the individual IMU publishers will publish at.
#      If set to -1, will use imu_data_rate to determine the rate at which to stream and publish
#      If set to 0, the stream will be turned off and the publisher will not be created
imu_raw_data_rate              : -1  # Rate of imu/data topic
imu_mag_data_rate              : -1  # Rate of mag topic
imu_gps_corr_data_rate         : -1  # Rate of gps_corr topic
                                     # Note that for philo devices (GX5, CV5, CX5), this will be published at the highest IMU data rate if "use_device_timestamp" is set to true
imu_overrange_status_data_rate : -1  # Rate of imu/overrange_status topic

# Static IMU message covariance values (the device does not generate these) 
# Since internally these are std::vector we need to use the rosparam tags 
imu_orientation_cov : [0.01, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.01]
imu_linear_cov      : [0.01, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.01]
imu_angular_cov     : [0.01, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.01]

# ****************************************************************** 
# GNSS Settings (only applicable for devices with GNSS) 
# ****************************************************************** 
gnss1_data_rate : 2

# The speed at which the individual GNSS1 publishers will publish at.
#      If set to -1, will use gnss1_data_rate to determine the rate at which to stream and publish
#      If set to 0, the stream will be turned off and the publisher will not be created
#
#      Note: The parameters' "gnss1_nav_sat_fix_data_rate", "gnss1_odom_data_rate" associated ROS messages share several MIP fields,
#            so if more than one is set to stream, and they are set to stream at different rates, messages will be published on both topics, at the higher rate
gnss1_nav_sat_fix_data_rate        : -1  # Rate of gnss1/fix topic
gnss1_odom_data_rate               : -1  # Rate of gnss1/odom topic
gnss1_time_reference_data_rate     : -1  # Rate of gnss1/time_ref topic
                                         # Note that on philo devices, if use_device_timestamp is set to true, this will be streamed at the highest GNSS rate
gnss1_fix_info_data_rate           : -1  # Rate of gnss1/fix_info topic
gnss1_sbas_info_data_rate          : -1  # Rate of gnss1/sbas_info topic
gnss1_rf_error_detection_data_rate : -1  # Rate of gnss1/rf_error_detection topic

# Antenna #1 lever arm offset vector
#     For GQ7 - in the vehicle frame wrt IMU origin (meters)
#     For all other models - in the IMU frame wrt IMU origin (meters)
#     Note: Make this as accurate as possible for good performance
gnss1_antenna_offset : [0.0, -0.7, -1.0]

# GNSS2 settings are only applicable for multi-GNSS systems (e.g. GQ7) 
gnss2_data_rate : 2

# The speed at which the individual GNSS2 publishers will publish at.
#      If set to -1, will use gnss2_data_rate to determine the rate at which to stream and publish
#      If set to 0, the stream will be turned off and the publisher will not be created
#
#      Note: The parameters' "gnss2_nav_sat_fix_data_rate", "gnss2_odom_data_rate" associated ROS messages share several MIP fields,
#            so if more than one is set to stream, and they are set to stream at different rates, messages will be published on both topics, at the higher rate
gnss2_nav_sat_fix_data_rate        : -1  # Rate of gnss2/fix topic
gnss2_odom_data_rate               : -1  # Rate of gnss2/odom topic
gnss2_time_reference_data_rate     : -1  # Rate of gnss2/time_ref topic
gnss2_fix_info_data_rate           : -1  # Rate of gnss2/fix_info topic
gnss2_sbas_info_data_rate          : -1  # Rate of gnss2/sbas_info topic
gnss2_rf_error_detection_data_rate : -1  # Rate of gnss1/rf_error_detection topic

# Antenna #2 lever arm offset vector (In the vehicle frame wrt IMU origin (meters) )
# Note: Make this as accurate as possible for good performance 
gnss2_antenna_offset : [0.0, 0.7, -1.0]

# (GQ7 Only) Enable RTK dongle interface
# Note: Enabling this will cause the node to publish on one of two topics depending
#       on the version of the RTK dongle connected to the GQ7
# Note: This is also required to be True in order to publish NMEA from the aux port
rtk_dongle_enable : False

# Speed at which RTK data will be published if an individual topic data rate is not specified
rtk_data_rate: 1

# The speed at which the individual RTK publishers will publish at.
#      If set to 0, the stream will be turned off and the publisher will not be created
rtk_status_data_rate : 1  # Rate of rtk/status or rtk/status_v1 topics

# (GQ7 Only) Allow the user to send RTCM messages to this node, and stream those messages to the GQ7
subscribe_rtcm : False
rtcm_topic     : "/rtcm"

# (GQ7 Only) Send NMEA sentences out on a ROS topic
# Note: Prior to version 3.0.0, this would only publish NMEA sentences from the aux port.
#       This option may now be used to publish NMEA sentences from the main port as well.
# Note: If the main port is configured to stream NMEA sentences, and the aux port is also connected,
#       this will publish NMEA sentences from both the main and aux port on the same topic.
publish_nmea   : False

# ****************************************************************** 
# Kalman Filter Settings (only applicable for devices with a Kalman Filter) 
# ****************************************************************** 
filter_data_rate : 10

# The speed at which the individual Filter publishers will publish at.
#      If set to -1, will use filter_data_rate to determine the rate at which to stream and publish
#      If set to 0, the stream will be turned off and the publisher will not be created
#
#      Note: The parameters' "filter_odom_data_rate", "filter_imu_data_rate", "filter_relative_odom_data_rate" associated ROS messages share several MIP fields,
#            so if more than one is set to stream, and they are set to stream at different rates, messages will be published on both topics, at the higher rate
#      Note: The parameters' "filter_navsatfix_data_rate", and "filter_aiding_status_data_rate" associated ROS messages share several MIP fields,
#            so if more than one is set to stream, and they are set to stream at different rates, messages will be published on both topics, at the higher rate
filter_status_data_rate                     : -1  # Rate of nav/status topic
filter_heading_data_rate                    : -1  # Rate of nav/heading topic
filter_heading_state_data_rate              : -1  # Rate of nav/heading_state topic
filter_navsatfix_data_rate                  : -1  # Rate of nav/fix topic
filter_odom_data_rate                       : -1  # Rate of nav/odom topic
filter_imu_data_rate                        : -1  # Rate of nav/filtered_imu/data
filter_relative_odom_data_rate              : -1  # Rate of nav/relative_pos topic and the transform between filter_frame_id and filter_child_frame_id
                                                  # Note that this data rate will also control the rate at which the transform between "filter_frame_id" and "filter_child_frame_id" will be published at
filter_aiding_status_data_rate              : -1  # Rate of gnss1/aiding_status and gnss2/aiding_status topics
filter_antenna_offset_correction_data_rate  : -1  # Rate of gnss1/antenna_offset_corection and gnss2/antenna_offset_correction topics
filter_gnss_dual_antenna_data_rate          : -1  # Rate of nav/dual_antenna_status topic
filter_aiding_measurement_summary_data_rate : -1  # Rate of nav/aiding_summary topic

# Sensor2vehicle frame transformation selector
#     0 = None, 1 = Euler Angles, 2 - matrix, 3 - quaternion
#     Notes: These are different ways of setting the same parameter in the device.
#            The different options are provided as a convenience.
#            Support for matrix and quaternion options is firmware version dependent (GQ7 supports Quaternion as of firmware 1.0.07)
#            Quaternion order is [i, j, k, w]
filter_sensor2vehicle_frame_selector : 1

filter_sensor2vehicle_frame_transformation_euler      : [0.0, 0.0, 0.0]
filter_sensor2vehicle_frame_transformation_matrix     : [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
filter_sensor2vehicle_frame_transformation_quaternion : [0.0, 0.0, 0.0, 1.0]

# Controls if the Kalman filter is reset after the settings are configured
filter_reset_after_config : True

# Controls if the Kalman filter will auto-init or requires manual initialization
filter_auto_init : True

# (All, except -10, and -15 products) Declination Source 1 = None, 2 = magnetic model, 3 = manual 
# Note: When using a CV7, this MUST be changed to either 1, or 3 or the node will not start
filter_declination_source : 2
filter_declination        : 0.23

# (All, except GQ7, CV7, -10, and -15 products) Heading Source 0 = None, 1 = magnetic, 2 = GNSS velocity (note: see manual for limitations)  
# Note: When using a -10/-AR product. This MUST be set to 0 or the node will not start
filter_heading_source : 1

# (GX5 and previous,-45 models only) Dynamics Mode 1 = Portable (default), 2 = Automotive, 3 = Airborne (<2Gs), 4 = Airborne High G (<4Gs) 
filter_dynamics_mode : 1

# Controls what kind of linear acceleration data is used in the Filter IMU message.
#      If this is set to true, the acceleration will not factor out gravity, if set to false gravity will be filtered out of the linear acceleration.
filter_use_compensated_accel : True

# ZUPT control 
filter_velocity_zupt_topic : "/moving_vel"
filter_angular_zupt_topic  : "/moving_ang"
filter_velocity_zupt       : True
filter_angular_zupt        : True

# (GQ7/CV7 full support, GX5-45 limited support) Adaptive filter settings
#      Adaptive level: 0 - off, 1 - Conservative, 2 = Moderate (default), 3 = agressive
#      Time limit: Max duration of measurement rejection prior to recovery, in milliseconds - default = 15000 
filter_adaptive_level         : 2
filter_adaptive_time_limit_ms : 15000

# (GQ7/CV7 only) Aiding measurement control 
filter_enable_gnss_pos_vel_aiding     : True
filter_enable_gnss_heading_aiding     : True
filter_enable_altimeter_aiding        : False
filter_enable_odometer_aiding         : False
filter_enable_magnetometer_aiding     : False
filter_enable_external_heading_aiding : False

#  External GPS Time Update Control
#      Notes:    filter_external_gps_time_topic should publish at no more than 1 Hz.
#                gps_leap_seconds should be updated to reflect the current number
#                of leap seconds.
filter_enable_external_gps_time_update : False
filter_external_gps_time_topic         : "/external_gps_time"
gps_leap_seconds                       : 18.0

# External Speed Control. This node will subscribe on this topic only if filter_enable_odometer_aiding is set to true
#      Notes: This subscription will be disabled if enable_hardware_odometer is set to true
filter_external_speed_topic : "/external_speed"

# Velocity frame control.
#      If set to false, the velocity will be reported in the NED/ENU frame
#      If set to true, the velocity will be reported in the vehicle frame
filter_vel_in_vehicle_frame : True

# (GQ7 Only) Reference point lever arm offset control.
#   Note: This offset will affect the position and velocity measurements in the following topics: nav/odom, nav/relative_pos/odom
#   Note: This offset is in the vehicle reference frame.
filter_lever_arm_offset: [0.0, 0.0, 0.0]

# (GQ7 Only) Hardware Odometer Control
enable_hardware_odometer : False
odometer_scaling         : 0.0
odometer_uncertainty     : 0.0

#  (GQ7/CV7 only) GPIO Configuration
#    Notes:    For information on possible configurations and specific pin options
#              refer to the MSCL MipNodeFeatures command, supportedGpioConfigurations.
#
#    GQ7 GPIO Pins =
#    1 - GPIO1 (primary port pin 7) - Features = 0 - Unused, 1 - GPIO, 2 - PPS, 3 - Encoder
#    2 - GPIO2 (primary port pin 9) - Features = 0 - Unused, 1 - GPIO, 2 - PPS, 3 - Encoder
#    3 - GPIO3 (aux port pin 7)     - Features = 0 - Unused, 1 - GPIO, 2 - PPS, 3 - Encoder
#    4 - GPIO4 (aux port pin 9)     - Features = 0 - Unused, 1 - GPIO, 2 - PPS, 3 - Encoder
#
#    CV7 GPIO Pins =
#    1 - GPIO1 (pin 7)  - Features = 0 - Unused, 1 - GPIO, 2 - PPS
#    2 - GPIO2 (pin 9)  - Features = 0 - Unused, 1 - GPIO, 2 - PPS
#    3 - GPIO3 (pin 6)  - Features = 0 - Unused, 1 - GPIO, 2 - PPS
#    4 - GPIO4 (pin 10) - Features = 0 - Unused, 1 - GPIO, 2 - PPS
#
#    Feature:
#    0 - Unused   - Behaviors = 0 - unused
#    1 - GPIO     - Behaviors = 0 - unused, 1 - input, 2 - output low, 3 - output high
#    2 - PPS      - Behaviors = 0 - unused, 1 - input, 2 - output
#    3 - Encoder  - Behaviors = 0 - unused, 1 - enc A, 2 - enc B
#
#    GPIO Behavior:
#    0 - Unused
#    1 - Input
#    2 - Output Low
#    3 - Output High
#
#    PPS Behavior:
#    0 - Unused
#    1 - Input
#    2 - Output
#
#    Encoder Behavior:
#    0 - Unused
#    1 - Encoder A
#    2 - Encoder B
#
#    Pin Mode Bitfield:
#    1 - open drain
#    2 - pulldown
#    4 - pullup
gpio_config    : False

gpio1_feature  : 0
gpio1_behavior : 0
gpio1_pin_mode : 0

gpio2_feature  : 0
gpio2_behavior : 0
gpio2_pin_mode : 0

gpio3_feature  : 0
gpio3_behavior : 0
gpio3_pin_mode : 0

gpio4_feature  : 0
gpio4_behavior : 0
gpio4_pin_mode : 0

# (GQ7 only) Filter Initialization control

#   Init Condition source =
#   0 - auto pos, vel, attitude (default)
#   1 - auto pos, vel, roll, pitch, manual heading
#   2 - auto pos, vel, manual attitude
#   3 - manual pos, vel, attitude
#
#   Auto-Heading alignment selector (note this is a bitfield, you can use more than 1 source) =
#   Bit 0 - Dual-antenna GNSS
#   Bit 1 - GNSS kinematic (requires motion, e.g. a GNSS velocity)
#   Bit 2 - Magnetometer
#
#   Reference frame =
#   1 - WGS84 Earth-fixed, earth centered (ECEF) position, velocity, attitude
#   2 - WGS84 Latitude, Longitude, height above ellipsoid position, NED velocity and attitude
filter_init_condition_src              : 0
filter_auto_heading_alignment_selector : 1
filter_init_reference_frame            : 2
filter_init_position : [0.0, 0.0, 0.0]
filter_init_velocity : [0.0, 0.0, 0.0]
filter_init_attitude : [0.0, 0.0, 0.0]

# (GQ7 only) Relative Position Configuration
#   Reference frame =
#   1 - Relative ECEF position
#   2 - Relative LLH position
#
#   Source =
#   0 - Position will be reported relative to the base station. filter_relative_position_ref will be ignored
#   1 - Position will be reported relative to filter_relative_position_ref
#
#   Reference position - Units provided by reference frame (ECEF - meters, LLH - deg, deg, meters)
#   Note: prior to firmware version 1.0.06 this command will fail for non-positive heights.  1.0.06 fixes this)
filter_relative_position_config : False
filter_relative_position_frame  : 2
filter_relative_position_source : 1
filter_relative_position_ref    : [0.0, 0.0, 0.01]

# (GQ7 only) Speed Lever Arm Configuration
#   Lever Arm - In vehicle reference frame (meters)
filter_speed_lever_arm : [0.0, 0.0, 0.0]

# (GQ7 only) Wheeled Vehicle Constraint Control
#    Note: When enabled, the filter uses the assumption that velocity is constrained to the primary vehicle axis.
#          By convention, the primary vehicle axis is the vehicle X-axis
filter_enable_wheeled_vehicle_constraint : False

# (GQ7 only) Vertical Gyro Constraint Control
#    Note: When enabled and no valid GNSS measurements are available, the filter uses the accelerometers to track
#          pitch and roll under the assumption that the sensor platform is not undergoing linear acceleration.
#          This constraint is useful to maintain accurate pitch and roll during GNSS signal outages.
filter_enable_vertical_gyro_constraint : False

# (GQ7 only) GNSS Antenna Calibration Control
# Note: When enabled, the filter will enable lever arm error tracking, up to the maximum offset specified in meters.
filter_enable_gnss_antenna_cal     : True
filter_gnss_antenna_cal_max_offset : 0.1

# (GQ7/CV7 only) PPS Source
#    PPS Source =
#    0 - Disabled
#    1 - Reciever 1 (default)
#    2 - Reciever 2
#    3 - GPIO (provided by external source if supported). Use the GPIO config above to further configure
#    4 - Generated from system oscillator
filter_pps_source : 1

# (GQ7 only) SBAS options
sbas_enable: True
sbas_enable_ranging: False
sbas_enable_corrections: True
sbas_apply_integrity: False

# (GQ7 only) SBAS included PRNs
#  Note: ROS2 can't handle empty arrays in a yml file, so uncomment this line and fill it in if you want to specify PRNs
#sbas_included_prns: []

# (GQ7 only) NMEA message format. If set to false, all NMEA message configuration will not have any affect
nmea_message_config: False

# Allow NMEA messages with the same talker IDs on different data sources (descriptor sets)
# In most cases, this should be set to False, as multiple messages of the same type with the same talker ID from a different descriptor set could cause confusion when parsing.
nmea_message_allow_duplicate_talker_ids: False

# NMEA messages in the sensor (IMU) descriptor set
# In order to enable a message, set nmea_message_config to true, and then change the 'data_rate' of the sentences you want to the desired rate in hertz
# Note: In order to publish, 'publish_nmea' must also be set to True
imu_nmea_prkr_data_rate: 0

# NMEA messages in the GNSS1 descriptor set
# In order to enable a message, set nmea_message_config to true, and then change the 'data_rate' of the sentences you want to the desired rate in hertz
#
# Note: In order to publish, 'publish_nmea' must also be set to True
#
# Note: gnss1_nmea_talker_id can be any of the follwing numeric values:
#         1 - Sentences will start with GN
#         2 - Sentences will start with GP
#         3 - Sentences will start with GA
#         4 - Sentences will start with GL
#       The purpose of the talker ID is to differentiate when the same message_id comes from different data sources (descriptor sets)
#       The gnss1_nmea_talker_id will be applied to all NMEA messages from the GNSS1 descriptor set
gnss1_nmea_talker_id: 1
gnss1_nmea_gga_data_rate: 0
gnss1_nmea_gll_data_rate: 0
gnss1_nmea_gsv_data_rate: 0  # Note that this message_id will not use the gnss1_talker_id since the talker ID will come from the actual constellation the message originates from
gnss1_nmea_rmc_data_rate: 0
gnss1_nmea_vtg_data_rate: 0
gnss1_nmea_hdt_data_rate: 0
gnss1_nmea_zda_data_rate: 0

# NMEA messages in the GNSS2 descriptor set
# In order to enable a message, set nmea_message_config to true, and then change the 'data_rate' of the sentences you want to the desired rate in hertz
#
# Note: In order to publish, 'publish_nmea' must also be set to True
#
# Note: gnss2_nmea_talker_id can be any of the follwing numeric values:
#         1 - Sentences will start with GN
#         2 - Sentences will start with GP
#         3 - Sentences will start with GA
#         4 - Sentences will start with GL
#       The purpose of the talker ID is to differentiate when the same message_id comes from different data sources (descriptor sets)
#       The gnss2_nmea_talker_id will be applied to all NMEA messages from the GNSS2 descriptor set
gnss2_nmea_talker_id: 2
gnss2_nmea_gga_data_rate: 0
gnss2_nmea_gll_data_rate: 0
gnss2_nmea_gsv_data_rate: 0  # Note that this message_id will not use the gnss1_talker_id since the talker ID will come from the actual constellation the message originates from
gnss2_nmea_rmc_data_rate: 0
gnss2_nmea_vtg_data_rate: 0
gnss2_nmea_hdt_data_rate: 0
gnss2_nmea_zda_data_rate: 0

# NMEA messages in the filter descriptor set
# In order to enable a message, set nmea_message_config to true, and then change the 'data_rate' of the sentences you want to the desired rate in hertz
#
# Note: In order to publish, 'publish_nmea' must also be set to True
#
# Note: filter_nmea_talker_id can be any of the follwing numeric values:
#         1 - Sentences will start with GN
#         2 - Sentences will start with GP
#         3 - Sentences will start with GA
#         4 - Sentences will start with GL
#       The purpose of the talker ID is to differentiate when the same message_id comes from different data sources (descriptor sets)
#       The filter_nmea_talker_id will be applied to all NMEA messages from the filter descriptor set
filter_nmea_talker_id: 3
filter_nmea_gga_data_rate: 0
filter_nmea_gll_data_rate: 0
filter_nmea_rmc_data_rate: 0
filter_nmea_hdt_data_rate: 0
filter_nmea_prka_data_rate: 0  # Note that this message_id will not have any talker ID on it since it is proprietary and can only come from the filter descriptor set

[robbiefish]

Hi @FLaiRobotics,

A couple things to note:

1. The hard and soft iron calibration needs to be done with the unit mounted on the robot. If you did the calibration in your hand or another way please redo it while mounted on the robot
2. Dynamic magnetic interference is common in mobile robots due to the proximity of electric motors and other sources. A good way to check interference is to have the sensor mounted on the robot with the robot off. Record the magnetometer output. Turn the robot on and while preventing it from moving, spin up the motors or other potential interference sources (gimbals, lidars, etc.) Stop the recording and plot the magnetometer output... did it change drastically? If so, the unit should be moved to a place on the robot that minimizes interference.

[FLaiRobotics]

Hi @robbiefish,

Thanks for your response.

Yes, we did perform soft and hard calibration with the sensor mounted on the robot.

Given the consistent pattern at each turn, could it be possible that the magnetometer/on-board sensors may be damaged or that the sensor is not using the stored calibrations (or) I am not configuring the params correctly?

Best, Debjit Ghosh

[robbiefish]

The parameters appear to be correct as far as I can tell.

It is always possible that the sensor is damaged in some way, but are you able to attempt number 2 from my comment above? I would like to rule out external magnetic interference first

[FLaiRobotics]

Hi @robbiefish,

No drastic change in values found: +/- 0.01

See comparison of x/y/z raw magnetometer readings; blue/green motors, etc. turned off/on:

Best, Debjit Ghosh

[github-actions[bot]]

This issue is stale because it has been open for 2 weeks with no activity. If the issue is still not resolved, please leave a comment describing what is still not working

[github-actions[bot]]

This issue was closed because it has been inactive for 2 weeks since being marked as stale. If the issue is still not resolved, please reopen the issue, and leave a comment describing what is still not working