Unmanned Systems Data Protocol and Format
For this week’s discussion, I am addressing the data format, protocols, and storage methods of an unmanned system, along with its onboard sensors, power, and storage requirements. The unmanned aerial system (UAS) that I have selected is the DJI Inspire 2 quadcopter with Zenmuse X5S camera and Lightbridge 2 video transmission.
Air Vehicle and Camera System
The DJI Inspire 2 is a quadcopter UAS that is capable of operating multiple payloads. It is typically paired with a gimballed camera, and is also equipped standard with downward and forward vision systems and an upward infrared sensor for obstacle avoidance (Inspire 2–Power Beyond Imagination, 2017). It is powered by a 4280 mAh battery that has a maximum power output of 22.8 V and 97.58 Wh, providing a maximum flight time of 25 minutes (Inspire 2 - TB50 Intelligent Flight Battery, 2017). The upward and downward obstacle avoidance systems are able to detect hazards at up to 5 m and 10 m, respectively, while the forward vision system is effective at up to 30 m. None of these three systems store or transmit data. Serving as the primary payload for the Inspire 2, the Zenmuse X5S camera system is a gimballed, 3-axis stabilized, high resolution camera system that is capable of recording video at a maximum resolution of up to 5.2K/30 frames per second. It records in the FAT32 file format, allowing video to be transferred directly to a computer without any additional software. When recording at maximum resolution, the Inspire 2’s control station can store up to 15 minutes of continuous recording, and reducing the resolution can increase storage up to 71 minutes (Inspire 2–Power Beyond Imagination, 2017).
Data Transmission
DJI’s Lightbridge 2 system is a truly innovative technology for transmitting data back to the user on the ground. The system operates in two frequency ranges: 5.725-5.825 GHz, and 2.400-2.483 GHz, broadcasting 1080p definition video out to a range of up to 5 km. The system can autonomously switch channels in order to reduce signal interference, and is able to simultaneously transmit up to two video streams from the same UAS using a picture in picture display, allowing the operator to see both the first person view (FPV) and the view from the main camera (DJI Lightbridge 2 – Specs, FAQ, Tutorials and Downloads, 2017). Additionally, and perhaps most importantly, the system can be enable to autonomously reduce its data transmission rate, reducing latency to as little as 50 micro seconds, which is up to 8 times faster than many WiFi systems (Locke, 2016). This speed aids the operator in flying the UAS via FPV in that he or she is seeing that the aircraft sees in near real time. The final innovation of the Lightbridge 2 technology is that it is fully integrated into the UAS’s ground control station (GCS), which reduces the amount of equipment that is needed to view the feed. The operator can fly and control the payload through the GCS, and the video from the selected camera, either the main, the FPV, or both, is viewed on either a smart phone or tablet, which can be mounted on the GCS handset. Additional video displays can be slaved off of the GCS, allowing others to not only view the feed, but to control the payload and aircraft as required as well. These slave systems connect wirelessly as well, at a distance of up to 50 m from the GCS (What Is Lightbridge 2 And How Does It Work?, 2014).
Overall, this combination of systems, while still quite expensive, provides excellent video and still picture resolution, combined with high data transmission rates and very low latency. In addition, its simplicity of design and relative few hardware components enable even novice users to easily set up and operate the entire system. One improvement that would enhance the experience for users of this system would be to increase the number of systems that can receive the video. Currently, only three video screens can be slaved off of the master via wireless connection. The addition of a wireless hub that is connected to the GCS could not only increase the number of users, but provide additional storage space for image and video capture.
References:
DJI Lightbridge 2 – Specs, FAQ, Tutorials and Downloads. (2017). Retrieved April 15,
2017, from http://www.dji.com/lightbridge-2/info#specs
Inspire 2 - TB50 Intelligent Flight Battery. (2017). Retrieved April 15, 2017, from
http://store.dji.com/product/inspire-2-intelligent-flight-battery#/?_k=05q62p
Inspire 2–Power Beyond Imagination. (2017). Retrieved April 15, 2017, from https://www
.dji.com/inspire-2
Locke, J. (2016, June 23). Comparing the DJI Phantom 4's Lightbridge vs. Yuneec
Typhoon H's WiFi – Drone Compares. Retrieved April 15, 2017, from http://
www.dronecompares.com/dji-phantom-4s-lightbridge-vs-yuneec-typhoon-hs-wifi/
What Is Lightbridge 2 And How Does It Work? (2014, September 11). Retrieved April 15,
2017, from http://myfirstdrone.com/news/dji-lightbridge-explained/