安装LIO-SAM.md

安装LIO-SAM

part1：安装依赖功能包

sudo apt-get install -y ros-melodic-navigation 
sudo apt-get install -y ros-melodic-robot-localization 
sudo apt-get install -y ros-melodic-robot-state-publisher 

**part2:**安装gtsam

git clone https://github.com/borglab/gtsam.git 
mkdir build && cd build 
cmake -DGTSAM_BUILD_WITH_MARCH_NATIVE=OFF .. 
sudo make install -j4 

part3:安装lio-sam

mkdir ~/lio-sam_ws/src 
cd ~/lio-sam_ws/src 
git clone https://github.com/TixiaoShan/LIO-SAM.git 
cd ../ 
catkin_make