How learning without GFW

Reference Links

Open links below in sequence.
(Things you need to learn, or following Overall Steps below but get nothing )
Some are combined by same web page.

ROS Tutorials

PX4 User Guide
PX4 Development Guide

Initial Setup

Ubuntu Development Environment
PX4 Buliding(Alternative)

Companion Computer

MAVLink
MAVROS Installation
MAVLink Router(Alternative)

VIO Introduction

MAVLink Interface
T265
VIO Git
VIO Dependence
Realsense-ros
Vision_to_Mavros

MAVLink Inspector
Flight Analysis which is really important.
(Matlab is available of course)

cnROS_T

cnPX4_UG
cnPX4_DG

PX4 User/Development Guide & ROS Tutorials in Chinese.
(Recommend BUT Reference)

QGC User Guide
Flight Modes
Flight Modes Setup
Vehicle Status Notifications !!! MUST Remember and Check before each Flying Mission !!!

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Notes

1. How to install Java & Ant correctly.(if using Flightplot)
2. connection between PX4 & Up Board

Overall Steps Beta

Capable in 20.04 tutorial has released. Please check at the end of the article.

Already have drones and a PC installed QGC?

Disarm your propellers First !
ESC Calibration
After ESC Calibration, press SWITCH button

Step 1. Choose Companion Computer

Intel NUC or Up Board (both used in my development) or others, with Ubuntu18.04 Mate or 16.04 (18.04 is officially recommend).

Step 2. PX4 Tool Chain

Set on the computer that using QGC for PX4 firmware upgrade.
CC is recommend.
Here’s reference with his notes

git clone https://github.com/PX4/Firmware.git --recursive
bash ./Firmware/Tools/setup/ubuntu.sh
reboot

sudo apt upgrade libignition-math2		//In case of (gazebo: symbol lookup error: xxx_xxx...)


//*************************
//QGC Linux Installtion

sudo usermod -a -G dialout $USER
sudo apt-get remove modemmanager -y
sudo apt install gstreamer1.0-plugins-bad gstreamer1.0-libav gstreamer1.0-gl -y
sudo apt install libqt5gui5 -y

/**Download QGC from Link above**/

chmod +x ./QGroundControl.AppImage
./QGroundControl.AppImage

//**************************
//Test if Tool Chain successfully configured
//Run QGC first

cd Firmware/
make px4_sitl_default jmavsim /*(or gazebo)*/		//Run Simulation

commander takeoff
commander land

Step 3. Basic Environment Setting: Ros Melodic installed. (or 16.04 & kinetic)

Before Ros installed (python2.7 for 18.04)

sudo apt install python2.7
sudo ln -s /usr/bin/python2.7 /usr/bin/python

Step 4. Install Mavros

MAVROS Installation

mavros is a ROS (1) package that enables MAVLink extendable communication between computers running ROS1 for any MAVLink enabled autopilot, ground station, or peripheral. MAVROS is the “official” supported bridge between ROS1 and the MAVLink protocol.

The easiest way to setup PX4 simulation with ROS on Ubuntu Linux is to use the standard installation script that can be found at Development Environment on Linux > Gazebo with ROS.

wget https://raw.githubusercontent.com/PX4/Devguide/master/build_scripts/ubuntu_sim_ros_melodic.sh

bash ubuntu_sim_ros_melodic.sh

or

sudo apt-get install ros-melodic-mavros ros-melodic-mavros-extras

//For 'wget' below
sudo apt-get install openssl
sudo apt-get install libssl-dev

wget https://raw.githubusercontent.com/mavlink/mavros/master/mavros/scripts/install_geographiclib_datasets.sh
sudo bash ./install_geographiclib_datasets.sh

Step 5. VIO Dependencies

1. ROS in step1.
2. Librealsense
   build it from source or following below bash code

export http_proxy="http://<proxy>:<port>"	//In case the public key cannot be retrieved

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-key F6E65AC044F831AC80A06380C8B3A55A6F3EFCDE || sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-key F6E65AC044F831AC80A06380C8B3A55A6F3EFCDE

sudo add-apt-repository "deb https://librealsense.intel.com/Debian/apt-repo $(lsb_release -cs) main" -u

sudo apt-get install librealsense2-dkms
sudo apt-get install librealsense2-utils

sudo apt-get install librealsense2-dev
sudo apt-get install librealsense2-dbg
/*Reconnect the Intel RealSense depth camera and run: 
	realsense-viewer
to verify the installation.*/

//sudo apt install python-catkin-tools

Step 6. T265 Dependencies

// realsense2_camera
sudo apt-get install ros-melodic-realsense2-camera
sudo apt install ros-melodic-cv-bridge ros-melodic-image-transport ros-melodic-tf ros-melodic-diagnostic-updater ros-melodic-ddynamic-reconfigure


//**************************
//Realsense SDK
git clone https://github.com/IntelRealSense/librealsense.git

cd librealsense
mkdir build
cd build

cmake ../ -DCMAKE_BUILD_TYPE=Release -DBUILD_EXAMPLES=true \
-DFORCE_RSUSB_BACKEND=ON -DBUILD_WITH_TM2=false -DIMPORT_DEPTH_CAM_FW=false

sudo make uninstall && make clean && make  && sudo make install


//**************************
//realsense-ros
mkdir -p ~/catkin_ws/src
cd ~/catkin_ws/src

git clone -b 2.2.7 https://github.com/IntelRealSense/realsense-ros.git
sudo apt-get install ros-melodic-ddynamic-reconfigure

catkin_init_workspace
cd ..

catkin_make clean

/****
There might be a "...find_if... ...suggested alternative: In file included from...from..." error while below catkin_make

vim /home/xxl/catkin_ws/src/realsense-ros/realsense2_camera/src/base_realsense_node.cpp +1854
//Then add 'std::' before 'find_if'
***/

catkin_make -DCATKIN_ENABLE_TESTING=False -DCMAKE_BUILD_TYPE=Release
catkin_make install

gedit ~/.bashrc
source ~/catkin_ws/devel/setup.bash
export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:~/catkin_ws/

Step 7. Vision_to_Mavros

This is vision_to_mavros project original, you may get something useful.

T265 POSE

mkdir -p ~/vision_ws/src
cd ~/vision_ws/src
git clone https://github.com/thien94/vision_to_mavros.git
catkin_init_workspace
cd ..
catkin_make

gedit ~/.bashrc
source ~/vision_ws/devel/setup.bash
export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:~/vision_ws/

cd vision_ws/src/vision_to_mavros/launch
vim t265_all_nodes.launch
//TURN <include file="$(find mavros)/launch/apm.launch"/> TO <include file="$(find mavros)/launch/px4.launch"/>

//***
If there is timesync warning during below step, you can

sudo vim /opt/ros/melodic/share/mavros/launch/px4_config.yaml

CHANGE line 12
/
timesync_rate: 0.0
/
/***

Step 8. VIO Installation

cd ~/catkin_ws/src
git clone https://github.com/Auterion/VIO.git

sudo apt install ros-melodic-mavros ros-melodic-mavros-extras		//melodic

cd ~/catkin_ws
catkin build px4_realsense_bridge

source ~/catkin_ws/devel/setup.bash
roslaunch px4_realsense_bridge bridge_mavros.launch		//This launch file starts the mavros node as well.

Step 8. QGC Parameter Setup

Set up Step2. computer’s QGC
Official

here’s my addition

Parameter name	Set the value
MPC_XY_VEL_MAX (X/Y Direction maximum speed limit )	0.50m/s(1.12mph)
MPC_Z_VEL_MAX_DN (Z Shaft lowering speed limit )	0.500m/s(1.12mph)
MPC_Z_VEL_MAX_UP (Z Shaft rising speed limit )	0.500m/s(1.12mph)
PWM_MAX Upper limit of channel frequency	2000us
PWM_MIN Lower limit of channel frequency	1000us
CBRK_USB_CHK	197848 ( Ban USB Check )
EKF2_AID_MASK ()	24 ( Visual peripheral number )
EKF2_HGT_MODE ( Height source )	Vision
SENS_TEL2_BAUD (TELEM2 Baud rate setting )	921600 8N1

Step 9. Connection CC with PX4

Official
...
...
...
Flight_Modes

USE FTDI FT232

sudo chmod 777 /dev/ttyUSB0
sudo vim /opt/ros/melodic/share/mavros/launch/px4.launch

//*****************
/CHANGE/

<arg name="fcu_url" default="/dev/ttyACM0:57600" />

/TO/

<arg name="fcu_url" default="/dev/ttyUSB0:460800" />
*****************//

UDEV<--------MUST DO IT

Step 10. Check Everything

roscore
rosrun turtlesim turtlesim_node
rosrun turtlesim turtle_teleop_key
/**********************************************/

roslaunch realsense2_camera demo_t265.launch
/***********************************************/

roslaunch mavros px4.launch
/***********************************************/

roslaunch realsense2_camera rs_t265.launch
roslaunch mavros px4.launch
roslaunch vision_to_mavros t265_tf_to_mavros.launch
/************************************************/

roslaunch vision_to_mavros t265_all_nodes.launch
rostopic echo mavros/vision_pose/pose

Step 11. Others

Ros launch automatically. (rm_bringup is recommend)
Easy way.
System Setting -----> login window ----> automatic login

vim start.sh
" #! /bin/bash source /opt/ros/melodic/setup.bash source ~/catkin_ws/devel/setup.bash source ~/vision_ws/devel/setup.bash roslaunch vision_to_mavros t265_all_nodes.launch "

sudo chmod 777 start.sh

Add start.sh to System Startup Application

Now Enjoy

Arm your paddle
RC----POSITION MODE

roslaunch vision_to_mavros t265_all_nodes.launch

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Capable in 20.04