# Copyright (C) 2016-2021 Swift Navigation Inc.
# Contact: https://support.swiftnav.com
#
# This source is subject to the license found in the file 'LICENSE' which must
# be distributed together with this source. All other rights reserved.
#
# THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
# EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.

package: swiftnav.sbp.imu
description: Inertial Measurement Unit (IMU) messages.
stable: True
public: True
include:
  - types.yaml
definitions:

 - MSG_IMU_RAW:
    id: 0x0900
    short_desc: Raw IMU data
    desc: >
      Raw data from the Inertial Measurement Unit, containing accelerometer and
      gyroscope readings. The sense of the measurements are to be aligned with
      the indications on the device itself. Measurement units, which are
      specific to the device hardware and settings, are communicated via the
      MSG_IMU_AUX message. If using "time since startup" local time tags, the
      receiving end will expect either a MSG_GNSS_TIME_OFFSET or MSG_PPS_TIME
      to establish the relationship between IMU time and GNSS time.
      
      Regardless of the timestamping mode, the timestamp is required to roll
      over to zero when reaching one week (604800 seconds, or 604800000 milliseconds).

      The time-tagging mode should not change throughout a run.
    fields:
        - tow:
            type: u32
            fields:
              - 30-31:
                  desc: Time status
                  values:
                      - 0: Reference epoch is start of current GPS week
                      - 1: Reference epoch is time of system startup
                      - 2: Reference epoch is unknown
                      - 3: Reference epoch is last PPS
              - 0-29:
                  desc: Time since reference epoch in milliseconds
            desc: >
              Milliseconds since reference epoch and time status.
        - tow_f:
            type: u8
            units: ms / 256
            desc: >
              Milliseconds since reference epoch, fractional part
        - acc_x:
            type: s16
            desc: Acceleration in the IMU frame X axis
        - acc_y:
            type: s16
            desc: Acceleration in the IMU frame Y axis
        - acc_z:
            type: s16
            desc: Acceleration in the IMU frame Z axis
        - gyr_x:
            type: s16
            desc: Angular rate around IMU frame X axis
        - gyr_y:
            type: s16
            desc: Angular rate around IMU frame Y axis
        - gyr_z:
            type: s16
            desc: Angular rate around IMU frame Z axis

 - MSG_IMU_AUX:
    id: 0x0901
    short_desc: Auxiliary IMU data
    desc: >
      Auxiliary data specific to a particular IMU. The `imu_type` field will
      always be consistent but the rest of the payload is device specific and
      depends on the value of `imu_type`.
    fields:
        - imu_type:
            type: u8
            desc: IMU type
            fields:
              - 0-7:
                  desc: IMU Type
                  values:
                      - 0: Bosch BMI160
                      - 1: ST Microelectronics ASM330LLH
                      - 3: TDK ICM-42670
                      - 4: Murata SCHA634-D03
                      - 5: TDK IAM-20680HP
        - temp:
            type: s16
            desc: Raw IMU temperature
        - imu_conf:
            type: u8
            desc: IMU configuration
            fields:
              - 4-7:
                  desc: Gyroscope Range
                  values:
                      - 0: +/- 2000 deg / s
                      - 1: +/- 1000 deg / s
                      - 2: +/- 500 deg / s
                      - 3: +/- 250 deg / s
                      - 4: +/- 125 deg / s
                      - 5: +/- 300 deg / s
              - 0-3:
                  desc: Accelerometer Range
                  values:
                      - 0: +/- 2g
                      - 1: +/- 4g
                      - 2: +/- 8g
                      - 3: +/- 16g
                      - 4: +/- 6g

 - MSG_IMU_COMP:
    id: 0x0905
    short_desc: Compensated IMU data
    desc: >
      Data from the Inertial Measurement Unit, containing accelerometer and
      gyroscope readings compensated for estimated errors and constant 
      physical effects. The output is valid for inertially referenced center 
      of navigation (IMU body frame) represented in vehicle body frame.
    fields:
        - time:
            type: u64
            units: microseconds
            desc: Microseconds since reference epoch
        - flags:
            type: u16
            desc: Contains the applied compensation parameters and time synchronization mode
            fields:
              - 7-15: 
                  desc: Reserved     
              - 6: 
                  desc: Gyroscope-errors-compensated      
              - 5: 
                  desc: Accelerometer-errors-compensated      
              - 4: 
                  desc: Coriolis-effect-compensated     
              - 3: 
                  desc: Earth-roration-rate-compensated     
              - 2: 
                  desc: Earth-gravity-compensated  
              - 0-1:
                  desc: Time status
                  values:
                    - 0: Reference epoch is start of current GPS week
                    - 1: Reference epoch is time of system startup
                    - 2: Reference epoch is unknown
                    - 3: Reference epoch is last PPS  
        - acc_comp_x:
            type: s32
            units: 1e-6 m/s^2
            desc: Compensated acceleration X axis
        - acc_comp_y:
            type: s32
            units: 1e-6 m/s^2
            desc: Compensated acceleration Y axis
        - acc_comp_z:
            type: s32
            units: 1e-6 m/s^2
            desc: Compensated acceleration Z axis
        - gyr_comp_x:
            type: s32
            units: 1e-6 deg/s
            desc: Compensated angular rate X axis
        - gyr_comp_y:
            type: s32
            units: 1e-6 deg/s
            desc: Compensated angular rate Y axis
        - gyr_comp_z:
            type: s32
            units: 1e-6 deg/s
            desc: Compensated angular rate Z axis