1. FPGA baed platforms（Field－Programmable Gate Array）即现场可编程门阵列
1)Phenix Pro(RobSense Tech公司开发, 固件开源为：基于自主定制的无人机实时操作系统（UOS）)
It is built on reconfigurable (可重构) System on a Chip (SoC) designed and developed by RobSense Tech, founded in 2015 and located in Hangzhou China.
The flight controller is equipped with the real-time operating system and Linux-based Robot Operating System(ROS).The flight platform supports 20+ interfaces includeing on-board sensors, mmWave radar, thermal camera,ultra-vision HD video transceiver via software defined radio,etc. In addition,its hardware(FPGA) acceleration(硬件加速能力) enables computer vision and Deep Neural Network algorithms applications. It runs FreeRTOS based UAV real-time operating system(PhenOS) that contains a built in multi-task scheduling, and ROS for intelligent algorithms and hardware resources management. Fig. 2-a shows Phenix Pro flight controller and Fig. 2-b shows its circuit board. The schematic of this platform is closed-source, however, the project's software is open under The GNU General Public License(GPL)v3 license.
Phenix Pro 搭载业界首创的基于SoC（ARM+FPGA）架构的无人机实时操作系统（UOS）和优秀的飞行控制算法。ARM双核处理器提供实时的自动控制与人机交互性能的同时，FPGA可以实现计算机视觉、卷积神经网络等算法的硬件加速并降低功耗。三余度IMU+三余度GPS.
2)OcPoC(Octagonal Pilot on Chip):(Aerotenna公司开发, 运行固件为APM)
It is developed by Aerotenna Company, founded in 2015 and located in Bioscience and Technology Business Center, University of Kansas, USA. OcPoC expands its input and output capabilities to include fully programmable PWM, PPM, and GPIO pins to integrate with a vast number of different sensor additions. It also include many other standardized connectors for peripherals(外围设备) such as GPS, CSI camera link, and SD card. It runs ArduPilot software platform.
Fig. 3-a shows OcPoC flight controller and Fig. 3-b shows its circuit board. The schematic of this platform is closed-source.
2. ARM-based platforms
1) PIXHAWK/PX4:(苏黎世大学的 Computer Vision and Geometry Lab and Autonomous System Lab，固件为PX4和APM)
It is a computer vision research based flight control designed by Computer Vision and Geometry Lab of ETH Zurich and Autonomous System Lab. It is an evolution of the PX4 flight controller system(i.e., enclosure(密集化) and perhaps modified connections(改进接口)). It consists of a PX4-Flight Management Unit(FMU) controller and a PX4-IO integrated(集成) on a single board with additional IO, Memory and other features. In addition, it works closely with the Linux Foundation DroneCode project.
Fig. 4-a shows PIXHAWK flight controller and Fig. 4-b shows its main circuit board; PX4. The project is available under the Berkeley Software Distribution(BSD) license.
2) PIXHAWK 2:(PX4 and ArduPilot 团队，固件为PX4和APM)
It grows from the Pixhawk Hardware Project and done as a group effort by the PX4 and ArduPilot teams. It is a small cube , has triple redundant(三倍冗余) IMU's, and up to 3 GPS modules. All connection (I/Os) to the cube is in one single DF17 connector. Its carrier has an interface to Intel Edition (works as a companion computer(伴随的电脑)).重点
Fig. 5-a shows PIXHAWK 2 enclosure and Fig. 5-b shows its circuit board. The Pixhawk 2 schematics(电路图) are open under the CC-BY-SA-3.0 license.
3) Paparazzi & Chimera:(ENAC Lab，固件为 Paparazzi autopilot system)
It is the first and the oldest open-source drone hardware and softeware project. It is developed in Ecole Nationale de I'Aviation Civil (ENAC) UAV Lab since 2003. It encompasses(集成) autopilot systems and ground station software for multicopters/multirotors, fixed-wing, helicopters and hybrid aircrafe ("Flexible open architecture for UASs integration(集成) into the airspace: Paparazzi autopilot system", in 2016 IEEE/A-IAA 35th Digital Avionics Systems Conference(DASC), Sept 2016, pp.1-7.). In March 2017, ENAC Lab released a new autopilot named Chimera that is based on the latest STM32F7 Microcontroller Unit (MCU). (配备ARM® Cortex®-M7内核的超高性能STM32F7系列)Fig. 6 shows Paparazzi Chimera circuit board. The hardware and sofeware of the project are available under the GPL licence.
4) CC3D & Atom:(OpenPilot/LibraPilot公司，固件为：OpenPilot/LibraPilot firmware)
They are two flight controller s have the same functionalities but defferent in size. They are developed by OpenPilot which became LibraPilot recently. The CC3D and Atom flight controllers have all types of stabilizations hardware which run the OpenPilot/LibraPilot firmware. They can be configured (安装配置) to fly any airframe from fixed-wing to an octocopter using the OpenPilot/LibraPilot. The hardware and the sofeware of the project are available under the GPLv3 license. Fig. 7-a and b show CC#D and Atom circuit boards, respectively.
3. Atmel-based platforms
1) Ardupilot Mega(APM):(DIY Drones community开发，运行固件为ArduPilot)
It is an Arduino Mega-based autopilot system developed by DIY Drones community as an upgrade of ArduPilot flight control. It is able to control autonomous multicopters, fixed-wing aircraft, traditional helicopters, ground rovers and antenna trackers. Fig. 8-a shows ArduPilot Mega(APM) v2.8 unit and Fig. 8-b shows its circuit board. The project is open under GPLv3 license.
The design of FlyMaple is based on the maple, which is an Arduino style ARM processor. Fig. 9 shows Flymaple flight controller board. The project is under GPLv3 license.
4. Raspberry Pi based platforms(由Erle Robotics公司开发)
1) Erle-Brain 3:
It is Linux based open pilot for drones developed by Erle Robotics, Spain. It combines an embedded Linux computer (Raspberry Pi) and a daughter board (PXFmini) containing several sensors, IO and power electronics. The PXFmini is an open hardware autopilot shield for making robots and drones meant for the Raspberry Pi family. It is build on top of the Dronecode Foundation technologies.
Fig. 10-a shows Erle-Brain 3 autopilot and Fig. 10-b shows lts parts (PXFmini + Raspberry Pi). The PXFmini schematics are open under the Creative Commons Attribution-NonCommercial-ShareAlike (CC BY-NC_SA) license.
重要信息提取：
1. STM32F7 Microcontroller Unit (MCU). (配备ARM® Cortex®-M7内核的超高性能STM32F7系列)。
2. FPGA（Field－Programmable Gate Array），即现场可编程门阵列，非常先进的技术。
1) Phenix Pro便是基于该处理器，运行固件为基于SoC（ARM+FPGA）架构的无人机实时操作系统（UOS）。
2) ARM双核搭配FPGA硬件加速，令计算机视觉、神经网络等人工智能技术在无人机上实时运算成为可能，效能比超GPU同类型方案两个数量级以上。
3) Phenix Pro支持智能感知环境、闪避障碍物、全自主飞行。
4) Phenix Pro可以轻松兼容20种以上不同设备（传感器）同时接入。
3. PIXHAWK/PX4: It is a computer vision research based flight control designed by Computer Vision and Geometry Lab of ETH Zurich and Autonomous Systems Lab.竟然是基于飞控的计算机视觉研究，并没有发现这点，之后在仔细研究一下，究竟是哪个地方体现了计算机视觉。
4. PIXHAWK 2:
1) All connection (I/Os) to the cube is in one single DF17 connector.(只有一个接口).
2) Its carrier board has an interface to Intel Edison (works as a companion computer). (竟然还可以附带一个微型计算机Intel Edison)
运行Linux系统！运行Linux系统！运行Linux系统！重要的事说三遍，我好像看到了什么！