Designing Unmanned Aerial Systems (UAS) Ground Control Stations (GCS) that replicate the sensory cues of manned aircraft is challenging, especially for small vehicles (Department of Defense Group 1-3) that return limited streams of telemetry data. A compilation of accident studies by Marshall, Barnhart, Shappee, and Most (2016) highlights that 32-69% of events involved human factors. While analysis varied by study, a clear theme emerged that improvements to the human-machine interface could mitigate training shortfalls, poor decision making, and perception errors. The following paper investigates the Optimum Solutions Transportable Ground Station from a human factors perspective.
Functional Analysis
The Transportable Ground Station (TGS) is a portable UAS GCS that provides mission management, command & control (C2), and sensor feedback, in a 70lb Pelican-style case with self-contained power supply (Optimum Solutions, 2016). Mission management is enabled by a laptop computer driving two monitors that are configurable for planning, telemetry, or data exploitation displays. The default planning software is Piccolo Command Center (PCC), due to the popularity of the Piccolo family of small autopilots, although any Windows-compatible third party software can be installed. PCC is used to create missions for autonomous flight path execution, terrain awareness, and perform simulations.
Figure 1. Optimum Solutions Transportable Ground Station (TGS) overview (left) and payload control stick detail (right). Copyright Optimum Solutions, 2016.
TGS C2 capabilities are facilitated by L, S, or C-band datalinks with several common physical interfaces available for reconfiguration in the field. TGS transmits uplinks with standard Frequency Modulation (FM), or Coded Orthogonal Frequency Division Multiplexing (COFDM), which has superior resistance to interference and multi-path effects (Keithley Instruments, 2008). Telemetry is downlinked from the vehicle, processed by PCC and displayed on horizontal map, pseudo “heads-up”, or numeric tables in the Windows interface. PCC enables updates to autonomous flight paths and the operator can make manual inputs via the trainer interface on Futaba remote controls. Payload C2 is designed primarily for video sensors, with separate joysticks and monitors providing payload command and feedback respectively (Figure 1, right).
Negative Human Factors Issues and Solutions
Two negative human factors deficiencies were identified on the TGS. On the pilot side, there are no means to build situational awareness of the vehicle’s immediate surroundings. Several stand-alone systems are available, however a solution should be consistent with the all-in-one theme of the TGS. FlightAware has teamed up with the Raspberry Pi community to exploit Automatic Dependent Surveillance-Broadcast (ADS-B) signals for less then $100 (FlightAware, 2016). The FlightAware Pro Stick software-defined radio is used inline with a compatible antenna and Raspberry Pi project computer to feed the PiAware desktop application. This provides pilots with real-time air traffic and weather data from stations within 200-300 miles on one of the two TGS mission planning monitors. The open Raspberry Pi architecture could also be used to export the data stream to the mission planning application for fusion with aircraft telemetry, increasing the crew’s SA.
On the payload side, the independent sensor joystick has a poor ergonomic effect on the operator. The portable nature of TGS means that the operator may not have the benefit of a seat conveniently aligned with the stick, which could lead to arm discomfort and tracking errors if the TGS is not positioned at their approximate elbow height (Human Solutions, 2017). Additionally, the payload function buttons are located directly aft of the stick in a likely forearm resting location, so that an operator needs to move one arm to make function inputs with the other, possibly inducing undesired payload movements. Lastly, the TGS may be located outside, where solar glare will likely degrade the operator’s perception of the picture, causing suboptimal settings to be applied. These deficiencies could be eliminated by replacing the fixed joystick and monitors with a video-game-style hand controller and first person view (FPV) goggles. For example, the SQDeal gaming controller with wired serial interface is infinitely adjustable in position with the same number of function buttons, and Fat Shark Dominator v3 goggles would provide a truer display for applying the proper sensor settings.
Conclusion
This short essay investigated the Optimum Solutions TGS UAS control station and revealed two human factors deficiencies. The first involved crew SA of vehicle environment and the second highlighted ergonomic problems with the sensor operator interface. The proposed solutions were installation of an open-standard ADS-B receiver and software, gaming controller, and FPV goggles.
References
FlightAware. (2016). Pro Stick and Pro Stick Plus - FlightAware's USB ADS-B and MLAT receiver ✈ FlightAware. Retrieved from http://flightaware.com/adsb/prostick/
Human Solutions. (2017). Calculate the ideal height for your ergonomic desk, chair and keyboard. Retrieved from http://www.thehumansolution.com/ergonomic-office-desk-chair-keyboard-height-calculator.html
Keithley Instruments, Inc. (2008). An Introduction to Orthogonal Frequency Division Multiplex Technology. Retrieved from http://www.ieee.li/pdf/viewgraphs/introduction_to_orthogonal_frequency_division_multiplex.pdf
Marshall, D. M., Barnhart, R. K., Shappee, E., & Most, M. (2016). Introduction to unmanned aircraft systems. Retrieved from http://site.ebrary.com.ezproxy.libproxy.db.erau.edu/lib/erau/detail.action?docID=10508871
Optimum Solutions. (2016). Transportable UAV GROUND STATION. Retrieved from http://www.optimumsolution.com/item16.html
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