simu-expr.md

MI-Calib: Multiple IMUs Spatiotemporal Calibrator

3.1 Simulation Test

We have already deployed a a program for generating simulation data. Just go to mi_calib/launch folder . Then we launch:

roslaunch mi_calib mi-calib-simu.launch

this would generate a simulated rosbag and some related ground-truth files:

• simu_imus.bag: the simulated rosbag:

  path:        simu_imus.bag
  version:     2.0
  duration:    7.9s
  start:       Jan 01 1970 08:00:01.00 (1.00)
  end:         Jan 01 1970 08:00:08.90 (8.90)
  size:        114.4 MB
  messages:    320000
  compression: none [148/148 chunks]
  types:       sensor_msgs/Imu [6a62c6daae103f4ff57a132d6f95cec2]
  topics:      /imu0/frame    3200 msgs    : sensor_msgs/Imu
               /imu1/frame    3200 msgs    : sensor_msgs/Imu
               /imu10/frame   3200 msgs    : sensor_msgs/Imu
               /imu11/frame   3200 msgs    : sensor_msgs/Imu
               /imu12/frame   3200 msgs    : sensor_msgs/Imu
               ...

• truth_align_to_imu0.yaml: the ground-truth spatiotemporal parametrer yaml-format file:

  CalibParam:
    EXTRI:
      SO3_BiToBr:
        - key: /imu0/frame
          value:
            qx: 0.0
            qy: 0.0
            qz: 0.0
            qw: 1
        - key: /imu1/frame
          value:
            qx: -0.8706789279833405
            qy: -0.1293033655598108
            qz: -0.3325697572013143
            qw: 0.338520605895337
         # ...
      POS_BiInBr:
        - key: /imu0/frame
          value:
            r0c0: 0
            r1c0: 0
            r2c0: 0
        - key: /imu1/frame
          value:
            r0c0: -0.9831585041044272
            r1c0: -1.350980588523048
            r2c0: 3.099204623917251
         # ...
    TEMPORAL:
      TIME_OFFSET_BiToBr:
        - key: /imu0/frame
          value: 0
        - key: /imu1/frame
          value: 0.001
        # ...
    INTRI:
      # ...
    GRAVITY:
      r0c0: 0
      r1c0: 0
      r2c0: -9.80

To perform calibration for the simulated data, you should change field 'config_path' in 'mi_calib/launch/mi-calib-prog.launch' to:

$(find mi_calib)/output/simu/config-simu.yaml

The file 'config-simu.yaml' is a configure file for 'MI-Calib', which could be found in folder 'mi_calib/output/simu'. The detail configure information could determined be by yourself. Then, we launch 'MI-Calib':

roslaunch mi_calib mi-calib-prog.launch

The calibration results would be output as a file named param.yaml.