0.前言

由于需要在GitHub下载代码，而国内访问受限，可能会出现一些问题，这里建议使用github国内镜像，参看：GitHub国内镜像网站，当然下面会给出具体解决方案。

1.步骤

1.1下载源码：git clone https://github.com/PX4/PX4-Autopilot.git

注意：
若该步骤出错，使用镜像,也就是运行：git clone https://hub.fastgit.xyz/PX4/PX4-Autopilot.git
或者使用gitee镜像：git clone https://gitee.com/robin_shaun/PX4_Firmware(注意使用这个方法时的源码文件名是PX4_Firmware)

1.2 切换到源码文件夹：cd PX4-Autopilot

1.3 更新工程子模块git submodule update --init --recursive

注意：
若该步骤出错，归根到底还是因为github访问不稳定。解决方案如下：
(方案的总体原则就是改变源码里面各个.gitmodules文件里的下载地址，需要注意的是源码位置，我这里是将源码放在主文件夹下，也就是 ~/PX4_Autopilot)

(1)源码主文件夹下

1. cd ~/PX4_Autopilot
2. gedit .gitmodules
   (注意：这里主要是为了修改文件，我用的是gedit编辑器，也可以用vim, nano，vs code之类的,后面相同)
   将 .gitmodules 中的内容更换为：

[submodule "mavlink/include/mavlink/v2.0"]  path = mavlink/include/mavlink/v2.0  url = https://gitee.com/robin_shaun/c_library_v2.git  branch = master [submodule "src/drivers/uavcan/libuavcan"]  path = src/drivers/uavcan/libuavcan  url = https://gitee.com/robin_shaun/uavcan.git  branch = px4 [submodule "Tools/jMAVSim"]  path = Tools/jMAVSim  url = https://gitee.com/robin_shaun/jMAVSim.git  branch = master [submodule "Tools/sitl_gazebo"]  path = Tools/sitl_gazebo  url = https://gitee.com/robin_shaun/sitl_gazebo.git  branch = master [submodule "src/lib/matrix"]  path = src/lib/matrix  url = https://gitee.com/robin_shaun/Matrix.git  branch = master [submodule "src/lib/ecl"]  path = src/lib/ecl  url = https://gitee.com/robin_shaun/ecl.git  branch = master [submodule "boards/atlflight/cmake_hexagon"]  path = boards/atlflight/cmake_hexagon  url = https://gitee.com/robin_shaun/cmake_hexagon.git  branch = px4 [submodule "src/drivers/gps/devices"]  path = src/drivers/gps/devices  url = https://gitee.com/robin_shaun/GpsDrivers.git  branch = master [submodule "src/modules/micrortps_bridge/micro-CDR"]  path = src/modules/micrortps_bridge/micro-CDR  url = https://gitee.com/robin_shaun/micro-CDR.git  branch = px4 [submodule "platforms/nuttx/NuttX/nuttx"]  path = platforms/nuttx/NuttX/nuttx  url = https://gitee.com/robin_shaun/NuttX.git  branch = px4_firmware_nuttx-9.1.0+ [submodule "platforms/nuttx/NuttX/apps"]  path = platforms/nuttx/NuttX/apps  url = https://gitee.com/robin_shaun/NuttX-apps.git  branch = px4_firmware_nuttx-9.1.0+ [submodule "platforms/qurt/dspal"]  path = platforms/qurt/dspal  url = https://gitee.com/robin_shaun/dspal.git [submodule "Tools/flightgear_bridge"]  path = Tools/flightgear_bridge  url = https://gitee.com/robin_shaun/PX4-FlightGear-Bridge.git  branch = master  [submodule "Tools/jsbsim_bridge"]  path = Tools/jsbsim_bridge  url = https://gitee.com/robin_shaun/px4-jsbsim-bridge.git [submodule "src/examples/gyro_fft/CMSIS_5"]  path = src/examples/gyro_fft/CMSIS_5  url = https://gitee.com/mirrors/CMSIS_5 

3. git submodule update --init

(2) libuavcan文件夹

1. cd ~/PX4_Autopilot/src/drivers/uavcan/libuavcan
2. gedit .gitmodules
   将 .gitmodules 中的内容更换为：

[submodule "dsdl"]  path = dsdl  url = https://gitee.com/robin_shaun/dsdl  branch = legacy-v0 [submodule "libuavcan/dsdl_compiler/pyuavcan"]  path = libuavcan/dsdl_compiler/pyuavcan  url = https://gitee.com/robin_shaun/pyuavcan [submodule "libuavcan_drivers/kinetis"]  path = libuavcan_drivers/kinetis  url = https://gitee.com/robin_shaun/libuavcan_kinetis.git 

3. git submodule update --init

(3) jMAVSim文件夹

1. cd ~/PX4_Autopilot/Tools/jMAVSim
2. gedit .gitmodules
   将 .gitmodules 中的内容更换为：

[submodule "jMAVlib"]  path = jMAVlib  url = https://gitee.com/robin_shaun/jMAVlib  branch = master 

3. git submodule update --init

(4) sitl_gazebo文件夹

1. cd ~/PX4_Autopilot/Tools/sitl_gazebo
2. gedit .gitmodules
   将 .gitmodules 中的内容更换为：

[submodule "external/OpticalFlow"]  path = external/OpticalFlow  url = https://gitee.com/robin_shaun/OpticalFlow 

3. git submodule update --init

(5) dspal文件夹

1. cd ~/PX4_Autopilot/platforms/qurt/dspal
2. gedit .gitmodules
   将 .gitmodules 中的内容更换为：

[submodule "cmake_hexagon"]  path = cmake_hexagon  url = https://gitee.com/robin_shaun/cmake_hexagon 

3. git submodule update --init

(6) pyuavcan文件夹

1. cd ~/PX4_Autopilot/src/drivers/uavcan/libuavcan/libuavcan/dsdl_compiler/pyuavcan
2. gedit .gitmodules
   将 .gitmodules 中的内容更换为：

[submodule "dsdl"]  path = dsdl  url = https://gitee.com/robin_shaun/dsdl 

3. git submodule update --init

(7) OpticalFlow文件夹

1. cd ~/PX4_Autopilot/Tools/sitl_gazebo/external/OpticalFlow
2. gedit .gitmodules
   将 .gitmodules 中的内容更换为：

[submodule "external/klt_feature_tracker"]  path = external/klt_feature_tracker  url = https://gitee.com/robin_shaun/klt_feature_tracker 

3. git submodule update --init

(8)终于修改完了，可以再次运行下这句命令

git submodule update --init 

1.4 编译

cd ~/PX4_Firmware make px4_sitl_default gazebo 

注意：
这一步可能会报错：ninja: build stopped: subcommand failed.

不要慌！

1. 先看看子模块是否更新成功。执行命令：git submodule update --init --recursive
   linux哲学，没有消息就是好消息，如果没有出现任何内容，说明子模块更新成功（看不懂什么是子模块也没问题，意思就是到此为止，没问题）。
2. 接下来清理下make环境就ok了：make clean
3. 最后再执行一次编译命令：make px4_sitl_default
   以下是我成功的界面
   

2. 打开gazebo make px4_sitl_default gazebo

注意：
如果gazebo出不来，可以这么做：

1. 清理一下：make distclean
2. 重新安装：sudo apt-get install ros-melodic-gazebo-dev
3. 再次运行：make px4_sitl_default gazebo
   

2. 祝你配置顺利！如有问题，欢迎讨论！