History of Unmanned Aerial Systems

History of UAS

Early Design: Ryan Model 147

The U.S. Army Ryan Model 147 “Lightning Bug”, derived from the early Firebee model, was in use from 1965 to 1975 and performed over 3400 reconnaissance missions (Blom, 2010). Most of these sorties were flown during the Vietnam War, where the Lightning Bug conducted visual and electronic signals intelligence gathering in both high and low altitude regimes. During the operational periods where the 147 was used, flight programs were uploaded nearly two weeks prior to launch and the only changes that could be made in the field were wind calculations (Blom, 2010). Many of the unmanned aerial vehicles (UAV) crashed, were subject to critical navigation errors, made unpredicted turns, and some even failed to switch to remote control prior to landing and would fly until running out of fuel (Blom, 2010).

Contemporary Design: MQ-1 Predator

The MQ-1 Predator is a widely recognized, capable and proven UAS that is undoubtedly a predecessor of the infamous “Firebee” and “Lightning Bug” aerial vehicles (Ehrhard, 2010). Initially designated as RQ-1 in the late 1990’s, the Predator has evolved into a multi-mission platform capable of intelligence, surveillance and reconnaissance (ISR) missions, laser designation, and air-to-ground strikes (Clausen, 2016). The Predator is able to execute pre-programmed flight routes, gather and send near real-time data feeds to operators, and safely conduct launch and recovery evolutions at an airfield or prepared surface using remote control or automated sequences (Clausen, 2016). 

Comparing and Contrasting the Designs

Designing variants and types. Typically with modern UAS, there are only a few variants of the same platform operational and development of new variants take significant amounts of time, however the 147 underwent a very rapid and “ad-hoc” development scheme to improve performance and make design changes. Figure 1 below illustrates the timeline of the changes made to the 147 airframe, with mission capabilities building over time. Additionally, instead of developing system enhancements and adding them to the existing airframe, Ryan engineers decided to make specific variants that were only used for certain missions and conditions. For example, cloud cover was obscuring image quality and degrading the photo capabilities for the Bravo variant, but the Charlie variant hosted a new technology to fly at low altitudes called the barometric low altitude control system (BLACS) (Ehrhard, 2010).

The level of control between the 147 and MQ-1 is different, in that the 147 had a “fire and forget” mentality where the UAV would be launched, and once it would return (or be recovered) then the data would be extracted and later analyzed. In terms of the MQ-1, the level of human-to-machine interface has greatly increased, with remote ground stations able to process the data feed and make rapid tactical decisions based on the ever changing battlespace environment (Clausen, 2016).

Launch and recovery. At the most basic level, the method of launch and recovery is vastly different when comparing the two airframes. With the Lightning Bug, a C-130 airframe would airlift the drone to a prescribed altitude and then release it, or would utilize jet-assisted takeoff (JATO) boosted capabilities from a land-base or ship (Blom, 2010). The reliability rates for a successful landing or recovery for the 147B model was approximately 62%, whereas the MQ-1 utilizes much more refined automated landing sequences with better global positioning system (GPS) fidelity to execute a more accurate and consistent recovery (Ehrhard, 2010). As the systems evolved, the needs for fulfilling mission requirements (i.e. overcoming cloud cover, launch and recovery constraints, better communication systems) became more clear, and the Lightning Bug paved the way for future UAS programs. The early programs provided the benefits of ad-hoc engineering design, valuable lessons learned for launch and recovery operations, and the need for rapid delivery of flight telemetry and intelligence data using sophisticated communications networks (Ehrhard, 2010). Determining the need for refining telemetry based on the early drone experimentation with altimeters, timer-programmers, and gyrocompasses enabled future UAS programs to develop a better navigation system which aided in higher vehicle recovery success rates (Ehrhard, 2010).

 

Figure 1. Ryan Model 147 Variants List. Retrieved from unmanned aerial systems: a historical perspective. Copyright US Army Combined Arms Center, 2010.

 

Influencing the Future based on New Technology

New technology such as wireless energy transfer using line of sight (LOS) systems can greatly increase the payload capacity for each airframe, in that extra space and storage previously occupied by heavy batteries and/or jet propulsion can be used for adjunct sensors (Morris, 2016). Additionally, when considering the use of power transmission over short-ranges, the capacitive power transmission (CPT) yields advantages such as minimizing the problem of electromagnetic interference (EMI) and greatly reducing power losses due to the operating environment (Mustafa, Muharam & Hattori, 2017). This new technological enhancement that allows for more usable space on UAS yields some distinct advantages that might influence the future evolution for UAV design. System enhancements would also need to be made to the ground stations to monitor power transmissions, and ensure that LOS is constantly maintained in order to provide adequate power for the vehicle under all operational conditions/flight regimes.

 

References

Blom, J. D. (2010, September). Unmanned aerial systems: A historical perspective. Aerial Reconnaissance: Drone Aircraft, 2(37), 1-353. 

Clausen, C. (2016, December 15). The evolution of the combat RPA. Retrieved from http://www.acc.af.mil/News/Article-Display/Article/1031490/the-evolution-of-the-combat-rpa/

Ehrhard, T. P. (2010, July). Air Force UAV’s: The secret history. Retrieved from http://www.dtic.mil/dtic/tr/fulltext/u2/a525674.pdf

Morris, D. Z. (2016, September 24). Demo shows drone flying under wireless power. Retrieved from http://fortune.com/2016/09/24/drone-flies-wireless-power/

Mostafa, T. M., Muharam, A., & Hattori, R. (2017, May 20). Wireless battery charging system for drones via capacitive power transfer. 2017 IEEE PELS Workshop: Emerging Technologies – Wireless Power Transfer. doi: 10.1109/WoW.2017.7959357