The external imu of r3live drifts, but the effect of fast-lio is better

[fanshixiong]

Hello, thank you very much for your work. When I use r3live, there is a lot of drift, especially at the corners. The straight line is not bad, but the same parameter configuration has achieved good results in fast-lio2.
My r3live version is the version with external imu rotation added, the warehouse is here: @tiny442 https://github.com/tlin442/r3live
The lidar I use is livox mid-70 with external imu, mynt-D1000 camera and imu, and the modified livox driver.
My computer is ubuntu20.04.
Here is my config file:

Lidar_front_end:
   lidar_type: 1   # 1 for Livox-avia, 3 for Ouster-OS1-64
   N_SCANS: 6
   using_raw_point: 1
   point_step: 1
   lidar_imu_rotm:
      # LiDAR is mounted rotated by 90 deg
      #[1, 0, 0,
      # 0, 0, 1,
      # 0, -1, 0]
      [ 0.016511, -0.999700,  0.018083,
       0.057071,  0.018999,  0.998189,
       -0.998234, -0.015449,  0.057368]
   lidar_imu_tranm: 
      [0.039342, 0.077608, 0.037443]

r3live_common:
   if_dump_log: 0                   # If recording ESIKF update log. [default = 0]
   record_offline_map: 1            # If recording offline map. [default = 1]
   pub_pt_minimum_views: 3          # Publish points which have been render up to "pub_pt_minimum_views" time. [default = 3]
   minimum_pts_size: 0.01           # The minimum distance for every two points in Global map (unit in meter). [default = 0.01] 
   image_downsample_ratio: 1        # The downsample ratio of the input image. [default = 1]
   estimate_i2c_extrinsic: 1        # If enable estimate the extrinsic between camera and IMU. [default = 1] 
   estimate_intrinsic: 1            # If enable estimate the online intrinsic calibration of the camera lens. [default = 1] 
   maximum_vio_tracked_pts: 600     # The maximum points for tracking. [default = 600]
   append_global_map_point_step: 4  # The point step of append point to global map. [default = 4]

   res_path: "/home/frans/code/r3live_proj/catkin_ws_r3live/src/r3live_/res"

r3live_vio:
   image_width: 1280
   image_height: 720
   camera_intrinsic:
       [655.005, 0, 679.029,
       0, 656.097, 358.596,
      0, 0, 1]
   camera_dist_coeffs: [-0.238605, 0.0435143, 0.000366211, -0.00272751, 0]  #k1, k2, p1, p2, k3
   
   # Fine extrinsic value. form imu2camera calibration.
   camera_ext_R:
         [0.999998,  0.00183758, 0.000849753,
         0.00184018,   -0.999994, -0.00307635,
         0.000844095,  0.00307791,   -0.999995]
   camera_ext_t: [0.0993128, 0.0117891, -0.176605] 

   
r3live_lio:        
   lio_update_point_step: 4   # Point step used for LIO update.  
   max_iteration: 2           # Maximum times of LIO esikf.
   lidar_time_delay: -0.092132       # The time-offset between LiDAR and IMU, provided by user. 
   filter_size_corner: 0.30   
   filter_size_surf: 0.30
   filter_size_surf_z: 0.30
   filter_size_map: 0.30

[stale]

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