S-FAST_LIO

Simplified Implementation of FAST_LIO

S-FAST_LIO is a simplified implementation of FAST_LIO (Xu, Wei, et al. "Fast-lio2: Fast direct lidar-inertial odometry."), which is modified from FAST_LIO. This code is clean and accessible. It is a reference material for SLAM beginners.The main modifications are as follows:

• The Sophus is used to define the state variables, instead of the complicated IKFOM
• The gravity component is directly defined by a Vector3d, thus the complicated calculation of two-dimensional manifold can be omitted
• The code structure has been optimized, and the unnecessary codes have been deleted
• Detailed Chinese notes are added to the code
• Support for Robosense LiDAR has been added

In addition, the following links are also my previous works. I strongly recommend reading them, since they are the interpretation and detailed equation derivation of FAST-LIO paper: FAST-LIO论文解读与详细公式推导(知乎)

FAST-LIO论文解读与详细公式推导(CSDN)

1. Prerequisites

1.1 Ubuntu and ROS

Ubuntu >= 16.04.

1.2. PCL && Eigen

PCL >= 1.8, Eigen >= 3.3.4.

1.3. livox_ros_driver

Follow livox_ros_driver Installation.

Source：Add the line source $Licox_ros_driver_dir$/devel/setup.bash to the end of file ~/.bashrc, where $Licox_ros_driver_dir$ is the directory of the livox ros driver workspace (should be the ws_livox directory if you completely followed the livox official document).

1.4. Sophus

We use the old version of Sophus

git clone https://github.com/strasdat/Sophus.git
cd Sophus
git checkout a621ff
mkdir build
cd build
cmake ../ -DUSE_BASIC_LOGGING=ON
make
sudo make install

2. Build S-FAST_LIO

Clone the repository and catkin_make:

cd ~/catkin_ws/src
git clone https://github.com/zlwang7/S-FAST_LIO.git
cd ../
catkin_make
source ~/catkin_ws/devel/setup.bash

3. Rosbag Example

3.1 Livox Avia Rosbag

Here we provide some additional Avia Rosbags. They are collected by Arafat-ninja.

Files: Can be downloaded from google drive. You can also directly use the Avia Rosbags provided by FAST_LIO (google drive).

Run:

roslaunch sfast_lio mapping_avia.launch
rosbag play YOUR_DOWNLOADED.bag

3.2 RS-LiDAR Rosbag

Datasets are collected by a RS-Helios LiDAR and an Xsens IMU.

Files: Can be downloaded from google drive.

Run:

roslaunch sfast_lio mapping_rs.launch
rosbag play YOUR_DOWNLOADED.bag

4. Directly Run

The same as FAST_LIO.

5.Acknowledgements

Thanks for the authors of FAST-LIO.