UAS (Unmanned Aerial System) Mission Planning

Introduction:

Unmanned aerial systems (UAS) are an increasingly prevalent technology that are used to accomplish a wide range of tasks. UAS often get associated with military operations, and often the word "drone" is used incorrectly to describe just one aspect of UAS. As the correct name implies, UAS consist of much more than just an unmanned vehicle. The consist of a platform, or flying device, a sensor, a ground station, radio control, and sometimes autopilot hardware. There are a number of other parts that can be included in UAS depending on it's use.

Not only does the word "drone" have a negative connotation, it also inaccurately describes UAS, implying that they are unmanned, unpiloted robots that operate free of human input. This is false, and the truth is that UAS should always be piloted, whether that be computationally or manually. Best practice for UAS is to have a 3 person team, consisting of a Pilot In Command, who mans the physical controls of the unmanned aerial vehicle (UAV), a Pilot At Controls, who operates sensors, and monitors from a computer, and an engineer/spotter who keeps close watch of the UAV, providing assistance to the PAC and PIC as needed.

UAS often are associated with miliary utility, but it is important to recognise their usefulness in many different situations. In geography, they can be used to assist in research providing aerial imagery, atmospheric monitoring, and many other remote sensing data. It can be a good alternative for other remote sensing utilities because it provides high spatial resolution, rapid results and possibly higher temporal resolution, at a reasonable price.

In this exercise, I looked at some unmanned aerial vehicles, and used a flight simulator software to get a better understanding of the different types of UAV's before acting as a consultant in various situations, recommending a UAS for assistance in various types of research.

Methods:

The first component to this exercise was to use a flight simulator to log flight time on a number of different types of UAV to get to know the strengths and weaknesses associated with each, and ultimately begin to understand some of the possible situations in which they could be used. Doing this, we used RealFlight 7.65 with real UAS remote controllers to try different platforms, utilizing a number of different flight views.

The first platform that I demoed was the Hexacopter 780. This is a multi-rotor platform with 6 propellers that is quite stable, and capable of slow flight speeds, which would allow for high spatial resolution aerial imagery and other remotely sensed data. However, multi-rotor platforms can't manage a very heavy payload, and since they have so many rotors, their battery life time suffers.

I logged around 30 minutes of flight time on the hexacopter on an ocean map with a shipwreck and a number of obstacles. I kept the wind low, as this was my first simulation, and the controls were hard enough as they were. I had five crashes in my 30 minutes of fly time, most of them involving crashes after attempted landings, or collisions with obstacles. 

The next platform I demoed was a fixed wing UAV called the Slinger. Fixed wing platforms are often useful for managing heavy payloads over large study areas. One main detriment to fixed wing UAVs is that they can only slow down to a point (where they will no longer provide lift), and thus cannot achieve as detailed remotely sensed image data as multi-rotored systems.

This is the Slinger, a common fixed wing platform. The controls were very different from the hexacopter, with much higher speed and touchy turns. I demoed this UAV at the Sierra Nevada map, experimenting with heavy winds. It was affected quite significantly by the presence of winds, making potential sampling impossible with adverse conditions. The chase view was the most fun of the different camera views, but I used the fixed view as well, which required some critical thinking about the relative controls. I had 6 crashes in the ~30 minutes that I tested this platform. Most of which were due to my overconfidence, testing maneuvers that would not be acceptable in the field.  

Next, I tested a Quadcopter X platform. This is a multi-rotor platform with just four rotors. The fewer rotors a UAV has, the less stable it is, especially in adverse conditions. However, it can have a longer battery life than multi-rotor platforms with more rotors.

I flew the quadcopter on the junkyard map, for about 30 minutes, experimenting with different views, including the 1st person view. This view allows you to have the perspective as if you were on the nose of the craft. This technology is widely used in real UAS scenarios. I had trouble with the fixed view, crashing four times within the first couple of minutes I attempted takeoff. I also found that succesfully landing the quadcopter was very difficult and required a very light touch with the accelerator joystick. I had a whopping total of 12 crashes in my half hour of flight time. 

Finally, I used the P-51 mustang platform for testing. This is another fixed wing craft, but it is significantly larger than the slinger model, and takes off from a runway on the ground. This model is also gas-powered which allows for longer flights.

I tested the P-51 Mustang on the Junkyard environment, and used the fixed view, chase cam, and cockpit cam for flights. With the Mustang I was able to achieve successful landings! I only had one or two successful landings with the other crafts, but this one I was able to land repeatedly. The controls were less touchy than the slingers', and it flew faster. I only crashed four times in the half hour of flight time logged.  

The final part of this exercise was to use our acquired knowledge to provide consultation for some scenarios created by our professor about possible use of UAS'.

Scenario 1: An atmospheric chemist is looking to place an ozone monitor, and other meteorological instruments onboard a UAS. She wants to put this over Lake Michigan, and would like to have this platform up as long as possible, and out several miles if she can.

Since she wants to cover a large area with a long flight time, this is a good scenario to use a fixed wing craft in. Though I only tested a couple of fixed-wing crafts, I believe that a larger one with a high payload would be advisable to accommodate multiple meteorological instruments. With this in mind, perhaps using a larger, gas-powered UAV would be in her best interest to increase flight time and distance. This would be more expensive, but necessary to accommodate her daunting task of mapping a large chunk of lake Michigan.

Scenario 6: An oil pipeline running through the Niger River delta is showing some signs of leaking. This is impacting both agriculture and loss of revenue to the company.

Depending on the magnitude of the oil leak at hand, a number of different UAS could be used. Since the scenario reads that the pipeline is showing signs of leaking, I will assume that the company is unsure of the problem and its whereabouts. This implies that there is a large area that must be covered to monitor the potential problem, and that sounds best suited for a fixed wing aircraft. Its low flight capabilities, long flight times and speed of data retrieval definitely demonstrate its preferability to satellite imagery, and because of this scenario's large geographic extent, a fixed wing craft is better suited for the task than a rotorred or multi-rotor system.

Conclusion:

This exercise was a valuable introduction to the growing field of UAS technology. These systems facilitate data collection for many different tasks, many of which are directly applicable to geography and geospatial data. Knowing the basics of what these unmanned aerial systems consist of (and what they don't consist of) is important in knowing ways in which we can solve geographic problems. More generally, being able to communicate our knowlege to a potential client is an important skill for workers in the geospatial field, as many clients aren't familiar with the technology. It is important to be able to look at a problem, and find a way to quantify it and collect data.

Sources:

http://www.iupac.org/publications/pac/special/0199/pdfs/engelhardt1.pdf