Unmanned Aerial System Mission Planning

Introduction

The objective of this weeks activity was to learn about and evaluate various UAS platforms. One part of the activity was to use  Real Flight 7.5 to test fly 4 different platforms. The next part of the activity was to look at different scenarios and give a recommendation and justification for what platform we think would work best for the specified project.  This part of the activity is of particular importance because this is a valuable skill to have. The goal of this activity, like our other activities is to gain skills that can be applied to real world situations.

Having an understanding of UAS is important because there are many applications of remote sensing that can be done using UAVs.  They are not without issues, legally and ethically speaking, but they are almost certainly going to continue to have a large impact on geospatial information systems. 

UAS platforms

UAS stands for Unmanned Aerial Systems.  Describing it as a system is more complete than just talking about UAVs- Unmanned Aerial Vehichles.  UAVs are part of a system, but they are not the only part.  There is also the software used to control the UAVs.  There is additional hardware involved which varies on what type of sensor you need to use.  Then there is also the software needed to compile and analyze the data collected by UAVs. 

In this activity we were largely focused on the role that UAVs played in Unmanned Aerial Systems.  UAVs are useful in that they can be cheaper than traditional aircraft, the can fly lower to the ground, and they can collect more detailed information because of this.  Costs of UAVs continue to decrease as time goes on.

UAVs can be divided into two general categories, fixed wing and multirotor.  There are trade offs in choosing one type over another, as both have properties that can be ideal for different situation.  A quick table of general comparisons between these two UAV types can be seen below.

Figure 1. Comparison of UAVproperties

Real Flight 7.5

Using a flight simulation is a great way to get some level of experience with flying UAV without the risk of destroying one.  The program Real Flight 7.5 offers a wide range of different UAVs and different airfields that can be used for practice.  Each of the airfields was unique, and gave you the opportunity to adjust conditions such as windspeed and direction, and visability.

Figure 2. Description of the Japenese Temple Airfield in Real Flight 7.5

There are also different obstacle courses and challanges that are offered within the program.  An example of one of these challanges that I tried was the baloon challange.  In this challange, the onbjective is to pop all of the baloons as quickly as possible.

Figure 3. Baloon challange with a fixed wing UAV in Real Flight 7.5 

One of the objectives was to log 30 minutes of flight time on 4 different UAV platforms (2 fixed wing, and 2 multirotor).  Shown below are the UAVs that I chose, the descriptions given in Real Flight 7.5, as well as my personal experiences with them.



Figure 4.  Quadcopter 1260 in Real Flight 7.5

I thought that for the most part the Quadcopter was easy to take off and land.  It moved slower compared to the fixed wings that I tried, but was much easier to hover.  The viewpoints fixed position, and nose were both relatively easy to use.  The most difficulties I had was when I tried incresing the wind, which made it more difficult to move.

Figure 5.  Ultra Sport in Real Flight 7.5

I generally found the fixed wing UAVs harder to fly compared with the multirotor UAVs.  The Ultrasport was relatively easy to fly during take off, but I had great difficulty when trying to sucessfully land it.  The Ultrasport seemed to be less affected by incresed wind speeds, was faster than the Quadcopter, and unable to hover.  It was easiest to fly using the nose viewpoint, and hardest to fly when using fixed position.

Figure 6. L-39 streamer cut in Real Flight 7.5 

The L-39 streamer cut was similar to the Ultrasport, but I found it harder to fly.  I wasn't able to switch direction as easily which led to crashing more often.  This plane was faster, and also much more tolerant of heavy wind conditions.  The viewpoint that I found most useful for this was chase, although I belive this is one of the least realistic viewpoints, because it would be rare to have that in a real world situation.

Figure 7. Tricopter 900 in Real Fligth 7.5

The tricopter 900 was similar to the quadcopter, but I found it to be less stable, and less tolerant of varying wind conditions.  The fixed position viewpoint was the easiest to use, and I found the nose viewpoint to be extremely disorienting.

During the time I was flying these UAVs in the flight simulator, I kept a log to record how long each flight lasted, as well as any other details of the flight that I thought would be important to mention. 

Figure 8. Flight log part 1

Figure 9.  Flight log part 2

Scenarios

The next part of this activity was to consider 2 situations and determine if they could benefit from using some type of UAS platform and then if so making a reccomendation for what this platform could potentially be. 

Methods

For each of the scenarios I tried to start by thinking of what needed to be done, and what were the characteristics needed in both the sensors and the UAVs.  My next step was to look up information that would be specific or relevant to the scenario. For example, when trying to make a reccomendation for the pinapple plantation I looked up studies of monitoring pinapple health and saw if any of these could also be related to remote sensing and aerial images.  I found that when I looked for it, I could find examples that were extremely relevant to the scenarios, and these helped me for my reccomendations for each of them.

Discussion 

Recommendations

1)  A power line company spends lots of money on a helicopter company monitoring and fixing problems on their line. One of the biggest costs is the helicopter having to fly up to these things just to see if there is a problem with the tower. Another issue is the cost of just figuring how to get to the things from the closest airport.

Using an unmanned aerial system would most liklely be of great benifit to this company in terms of saving costs.  At one point in time helicopters were probably the best monitoring solution, but now there are cheaper alternatives that could be utilized. 

There are already power companies that are using UAVs for inspections with great success. Finnish Energy Industries used UAVs with advanced sensors as part of a research project conducted with the Electricity Research Pool and saw a 50% reduction in costs compared with their traditional aerial survey methods.

I would recommend using essentially the same system that they did because of its proven effectiveness.  A helicopter or a quadcopter UAV should give you the stability to get high quality photos.  A high resolution camera would be enough to show any major problems with the powerline, but I would also reccomend having a laser scanner in order to get a 3-D model of the power lines and their surrounding terrains.  Having this might allow for more preventative work to be done, identifying potential problem areas, and avoiding those problems altogether.

Source:Transmission and Distribution World Magazine

2)  A pineapple plantation has about 8000 acres, and they want you to give them an idea of where they have vegetation that is not healthy, as well as help them out with when might be a good time to harvest.

I think that what will give you the best information about this field will be to have take a normalized difference vegetation index.  Although an NDVI can be done with ordinary aerial photos and satellite images, the resolution would not be very high. 

8000 acres is a relatively large area, so using a helicopter or quadcopter UAV would probably not be as efficient as using some form of fixed wing UAV.  As for the sensor that you should use, a research study on pinapple plantations in Malaysia found that an optical sensor called Greenseeker prduced by the tech company trimble was an effective way to get NDVI measurements.

Sources:  Pinapple Study  Greenseeker info
 

Conclusions

The activity was useful in acheiving the objectives that were set out.  I learned more about, and was able to evaluate the usefulness of various unmanned aerial systems in different situations.  The Real Flight simulator was great for actually getting a sense of what it would feel like to fly them, and the scenarios given were a great opportunity to do some additional research and develop a reccomendation based on our current knowledge of UAS.