I am currently trying to do 3D SLAM with two 2D Lidars and possibly additional IMU in ROS. However, there seems to be no ROS package available to meet my needs. The closest one would be laser_pipeline stack, but the documentation only tells me about fusioning LaserScans from "one source" although what I need is fusioning vertical scan and horizontal scan into one 3D PointCloud2. So I currently need another package to fusion scans from different sources. Anybody have an idea how to solve this problem?