UAS Streamflow Monitoring

Streamflow monitoring is a unique application of UAS. In many mountainous regions the water found in streams and creeks is a vital resource for farms where other sources of water is difficult to obtain. These lands rely on water from mountain sources to provide for agricultural needs as well as for human consumption. In the state of Colorado land owners have what are called water rights. These land owners who have water rights are entitled to a measured amount of water from naturally occurring sources such as rivers, streams, and creeks. To measure this flow, sensors are in place by the Colorado Division of Water Resources, however these sensors only monitor major waterways leaving land owners responsible for monitoring their own streams. This is typically accomplished with Parshall flumes – a device that is placed in the streamflow and can accurately measure the volume of water traveling through it (CSU, 2014). Often these water gauges are located in difficult to reach areas due to the natural terrain conditions of mountainous regions. This is where the use of UAS can be of benefit as it allows the land owners to monitor streamflow without having to travel along the difficult and often dangerous terrain. Additionally, the ability for UAS to operate with relatively low noise pollution gives UAS a much needed benefit in environments where domestic animals and wildlife reside. Three platforms that are ideally suited for streamflow monitoring are the DJI S900, the Lockheed Martin Indago, and the Aerovironment Qube UAS. As small VTOL UAS they are ideally suited for imaging tasks in mountainous regions.
DJI S900
The DJI S900 is a vertical takeoff and landing (VTOL) hexacopter. It is purpose built specifically for imaging payloads and is marketed towards photographers and videographers. However, because the target of streamflow monitoring is a visual gauge, the S900 is a capable platform for this task. Also because it is built with photography and videography in mind it is a very stable imaging platform. It is designed with arms eight degrees in inversion, and 3 degrees inclination (DJI, 2014) – creating a dihedral effect and making the platform more stable compared to a traditional helicopter configuration.
Lockheed Martin Indago
The Lockheed Martin Indago is a purpose built VTOL quadcopter. Designed with military and search and rescue in mind, the Indago is lightweight and portable yet rugged to meet professional applications. The entire system can be stored in a small briefcase, making this ideal for Water Resource personnel to travel with. Additionally, the ground control station (GCS) is weather resistant (Lockheed Martin, 2014) so as to maintain situational awareness even in poor environmental conditions, a benefit in mountain areas where weather is often unpredictable.
Aerovironment Qube
The Aerovironment Qube is also a quadcopter, and has been developed with search and rescue as its primary application. This makes it rugged and portable similar to the Lockheed Martin Indago. However, the Qube has a distinct commercial application advantage in the GCS – a system capable of being used on a touch-enabled tablet computer. This interface may prove to reduce the learning curve and attract a larger market of potential civilian operators.
Application Considerations
There are advantages to using small UAS (sUAS) for streamflow monitoring, such as portability, storage, and maneuverability. These are all needed elements in mountainous environments where the UAV may have to navigate small spaces, such as between trees, valleys, and boulders. Their agility is a benefit, however the drawback to these sUAS is flight time. By having to use small VTOL UAS, the battery life on these electric powered systems offers relatively little flight time, approximately 40 minutes for both the Indago and Qube, and 18 minutes for the S900. Additionally, there are legal barriers as directed by the Federal Aviation Administration (FAA) that limit UAS operation in the National Airspace System (NAS) to line of sight (LOS) only. Beyond line of sight (BLOS) is prohibited without authorization (FAA, 2014), this can be a challenge to operating in mountainous regions where there are many visual obstacles and hills to block view.


References:
DJI (2014). DJI Spreading Wings S900 (2014). Retrieved from:
http://www.dji.com/product/spreadingwings-s900/feature

Lockheed Martin (2014). Indago VTOL Quad Rotor (2014). Retrieved from:
http://www.lockheedmartin.com/us/products/procerus/quad-vtol.html

Aerovironment (2014). Qube UAS (2014). Retrieved from: https://www.avinc.com/public
safety/qube

Federal Aviation Administration (2014). Model Aircraft Operations Limits (2014). Retrieved
from:  https://www.faa.gov/uas/publications/model_aircraft_operators/

Colorado State University (2014). Father of the Flume: Ralph Parshall (2013). Water Resources
Archive. Retrieved from: http://lib.colostate.edu/archives/water/parshall/flume.html

UAS in the NAS

One of the great hurdles to unmanned aircraft system (UAS) integration into the national airspace system (NAS) is coordination – both with air traffic control (ATC) and other manned and unmanned aircraft. Safety is always priority, and the successful integration of manned and unmanned systems is dependent on keeping the skies safe regardless of the type of aircraft being flown. One way to ensure this safety is met is to treat unmanned systems as though they were manned. Vice president of the Airline Pilots Association Sean Cassidy stated that UAVs, “…should be certified in the same way manned aircraft are and that pilots should receive equivalent training. (Defense News, 2013).” This shows the mindset of aerospace professionals, and serves as good direction. To that end, UAS should be treated as any other aircraft, and should be equipped with similar technologies that facilitate positive ATC interactions. Transponders and sense-and-avoid capabilities are two technologies that medium to large UAS need in order to function safely with other aircraft. Maintenance should be on par if not greater than manned systems to set high standards and ensure accidents are not directly attributed to poor maintenance practices. This is especially important at the early stages of UAS NAS integration where UAS are already being looked at with concern and being introduced with much resistance from professionals and the general public alike. Every step needs to be taken to ensure an oversight is not to blame, especially during the early stages of integration.

Another area of importance to NAS integration are situational awareness issues. It is the nature of UAS to be lacking in naturally occurring situational awareness aids found in manned pilots, therefore, attempts should be made to mitigate this deficiency through integrated technology and on-board sensory payloads. The goal being to provide ground control stations (GCS) with all the situational awareness possible in an attempt to avoid in air collisions as well as maintain environmental awareness.

Lastly, all UAS need to have an emergency procedure with lost-link controls in place. Lost-link issues can be devastating to equipment and surroundings as is; add in a public setting in NAS and the results are potentially catastrophic. To avoid such scenarios, all UAS need to have multiple layers of safety and technologies to aid in the event of lost-link. Many companies are working toward lost-link technologies and the FAA and MITRE Corporation have come up with one device known as the Intelligent Analyzer. The goal of MITRE and the Intelligent Analyzer is to aid not only the ground pilots but ATC and other pilots in the area surrounding the UAS. The device transmits a message to ATC and pilots through emergency frequencies alerting them of the intent of the aircraft (MITRE, 2012). It is through these types of advancements that UAS will eventually fly safely with manned systems without negatively impacting controller workload and ATC operations.

References:
Defense News (2014). How a Large U.S. Navy UAV Crashed in Maryland, from 18,000 feet
(2013). Retrieved from: http://www.defensenews.com/article/20130107/C4ISR02/301070006/
MITRE Corporation (2014). Unmanned Aircraft System Airspace Integration: Intelligent
Analyzer (2012). Center for Advanced Aviation System Development. Retrieved from: https://www.mitre.org/sites/default/files/publications/Unmanned_Aircraft_System_Airspace_Integration_Intelligent_Analyzer.pdf