Overview of Data Storage and Transmission format in UAVs
Unmanned systems handle data storage and processing in three primary ways: onboard only, onboard and livestreaming, and livestreaming only. Their data storage and transmission design include internal storage, removable and or external storage through livestreaming to a computing infrastructure such as the ground control station (GCS) or cloud computing. Internal and removable storage can be achieved using solid state storage (SSD) technologies including micro secure digital (microSD). System logs contain readings from onboard internal and external sensor, operating parameters and various system execution states collected over time and are generally stored internally. Remote sensing data or mission specific data captured using mission specific sensors can also be stored internally depending on a number of factors that include system power requirements, mission type (time-sensitive or not), sensor type and data format and storage requirements.
The mission type normally dictates the design solution for the data format, protocol or storage scheme. For time-sensitive missions such as intelligence, reconnaissance and surveillance (ISR) activities where the timeliness of the data is critical to the success of the mission, the data is transmitted via a data link to a processing unit, ground control station or command center (Marshall et al., 2011). For example, the data collected in tracking a fire front is of no use to forest fire fighters if the data is even several minutes old. In such a scenario, the quality of the image is not as important as its timeliness and relevancy. On the other hand, remote-sensing application or where the value lies in quality of the data then the data can be stored internally. Generally, each sensor suite, for an unmanned system comes equipped with its own data storage, either fixed internally or removable (Marshall et al., 2011). The remainder of this paper summarizes the data storage and processing scheme employed by the C-Astral Bramor ppX unmanned aerial vehicle.
C-Astral Bromor ppX
The Bramor ppX unmanned aerial vehicle (UAV) is a fixed wing unmanned aerial system (UAS) that is ideal for real-time remote sensing applications. The airframe is designed to support multiple sensor suite payloads such as visible light optical flow cameras, thermal infrared cameras and multispectral cameras. Each sensor suite has a standard interface port that allows the onboard processing unit to directly control it. In addition, each sensor suite uses a universal serial bus (USB) connection to send its captured data to the UAV. The UAV maintains a secure internet protocol (IP) wireless connection as its data link to a ground control station or terminal with up to 40km line of sight range (C-Astral, n.d). It transmits the sensor data to the ground control station in real-time.
The ground control station is made up of proprietary communication hardware with standard communication interfaces to a tablet computer and a laptop that runs C3P Software. The C3P Software is the purpose build ground control software that is built for the C-Astral line of UAVs. It features standard mission planning, organizing and UAV control tools. It also annotates a live geo map with data streaming from the UAV to provide telemetry, vehicle status and other relevant information about the vehicles progress during a mission. Furthermore, it allows the operator to switch between the map view and live video stream.
There is no information provided on the compression or the quality of the video. However, it can be assumed that for real-time viewing at a distance of up to 40km, the image data could be compressed to decrease latency of the transmission to the ground control station. The internal storage of the laptop and the table computer are used in also storing the streaming data. The stored data can be exported to formats that can be used by leading photogrammetry software and video analytics packages. Finally, the software serves as a gateway to an online (cloud) flight logbook and data processing.
C-Astral Bramor ppX is a UAV best suited for ISR and continuous scanning mission. It has been used in various applications around the world for border monitoring, wildlife control, rangeland inspection and monitoring, precision agriculture and asset management (C-Astral, n.d). For data storage and processing, the Bramor ppX uses a high-speed IP link to its ground control station infrastructure to transmit data. Parts of the transmitted data is processed live by the C3P Software software to provide the pilot with important information on the mission. The data also stored on the tablet or laptop control that makes part of the ground control station. More importantly, further data processing capabilities and storage capacity is added through the use of online or cloud computing platforms.
C-Astral. (n.d). Enduring-Precision. Retrieved from http://www.c-astral.com/media/uploads/file/c-astral_2018_katalog_feb-WEB.pdf
Marshall, D. M., Barnhart, R. K., Hottman, S. B., Shappee, E., & Most, M. T. (Eds.). (2011). Introduction to unmanned aircraft systems. Retrieved from http://ebookcentral.proquest.com