Coordinate System and Topic Relationship

odom coordinate system is not fixed; its origin is the robot's initial position.

base_link坐标系 是机器人本体的坐标系，固定在机器人中心（如底盘）。当机器人移动时，/odom话题发布机器人运动数据，base_link坐标系会相对于odom坐标系移动。

laser_link and imu_link coordinate systems The position between base_link is static, so when base_link moves, other sub-coordinate systems will also move accordingly.

The odom coordinate system is the robot's estimated starting position based on data fed back from the robot's motor encoders or odometry, and it generally drifts.

The map coordinate system is the position at which the robot starts, estimated through algorithms using sensors such as LiDAR.

However, since using a tree-structured TF is recommended, we usually take the map coordinate frame as the root coordinate frame, so in this case map does not move in rviz2, and odom serves as the downstream coordinate frame of the map coordinate frame. (You can listen to Teacher Zhao's ROS1 course; it is explained very well here.)