This video shows some results for autonomous 3D outdoor mapping using two 2D lidars, an IMU, and a GPS. This taken with a Clearpath Husky outside the Clearpath office in Waterloo, Ontario. It uses my GPS waypoint navigation package in ROS to perform the autonomous navigation.
You can find the waypoint_nav software here: https://github.com/nickcharron/waypoint_nav
This demo also uses the mandala-mapping software to perform the 3D mapping. This package can be found here: https://github.com/nickcharron/mandala-mapping
Also see: https://www.youtube.com/watch?v=gpJlrqSyIJo&feature=youtu.be
See the full tutorial from Clearpath Robotics: http://www.clearpathrobotics.com/assets/guides/husky/HuskyGPSWaypointNav.html