  Recently, multi-sensors fusion has achieved significant progress in the field
of automobility to improve navigation and position performance. As the
prerequisite of the fusion algorithm, the demand for the extrinsic calibration
of multi-sensors is growing. To calculate the extrinsic parameter, many
researches have been dedicated to the two-step method, which integrates the
respective calibration in pairs. It is inefficient and incompact because of
losing sight of the constrain of all sensors. With regard to remove this
burden, an optimization-based IMU/Lidar/Camera co-calibration method is
proposed in the paper. Firstly, the IMU/camera and IMU/lidar online
calibrations are conducted, respectively. Then, the corner and surface feature
points in the chessboard are associated with the coarse result and the
camera/lidar constraint is constructed. Finally, construct the co-calibration
optimization to refine all extrinsic parameters. We evaluate the performance of
the proposed scheme in simulation and the result demonstrates that our proposed
method outperforms the two-step method.
