Activity 12: Introduction Unmanned Aerial Systems

Introduction

This week for field methods we did something a little bit different than the normal activities. This week was more a show and tell and step by step demonstration of how to use an Unmanned Aerial System (UAV). Professor Hupy and myself gave the class a demo of pre-flight procedures, data collection, and post flight procedures. The class learned how a typical day flying and collecting data goes from the arrival on the cite and taking weather conditions to UAV inspection and post flight data processing. professor Hupy and myself stressed safety precautions and following our flight plan to ensure a safe and productive demonstration for the class. We were again out at the Priory just south of town. The two UAV platforms we flew were the Matrix (Figure 1) and Iris (Figure 2).

Figure 1 is an IRIS made by 3D Robotics. This is an out of the box ready to fly UAV that costs around $700.

Figure 2 is the Matrix by Turbo Ace. This is an image of the one we flew for this exercise. It is a more do it yourself kind of platform that requires a lot of assembly and much more mechanical knowledge to construct. This is about 4 to 5 thousand dollars with all the electronics on it.

Methods

I was involved in this activity to help demonstrate so my steps and methods may be different from others in the class who got to take notes and watch the demo.I will base my methods section off of the flight procedure checklist and what a normal data collection mission would be like when I do my research with professor Hupy. Again this whole procedure is used in order to eliminate human error during set up, increase flight safety and prevent damage to our vehicles and sensors that are on board collecting data.

Step 1 Study Area

The first step to collecting data with a UAV is have a study area or a location that you are going to fly. When selecting an area to fly there are some things that need to be considered. The first is am I going to be close to people or putting others in danger by flying this area. We usually fly in areas of low population away from houses and people. Large open parks are ideal for flying. Another thing to consider is where can I take off and land from. It is good to have a flat open area with little to no vegetation on it. This reduces the risk of the UAV crashing into something like a tree or bush during take off and landing. Avoiding areas with power lines and cell towers is also important. The current flowing through the power lines and the signal coming off the tower can create electromagnetic pulses which can cause the compass and/or the GPS on the UAV to malfunction which could lead to a crash. In figure 3 you can see our study area in the yellow rectangle for our demonstration flight at the Priory. If you look at the map you can see the areas where my navigation points are from a previous week is very heavy tree cover and steep elevation. That is not a good area to land and take off in. The yellow rectangle is over an area that is flat with very few trees, no power lines and from this area you could see the UAV in the air at all times which is another study area consideration that needs to be thought about. Figure is a view from the take off location for our demonstration and also a ground shot of the yellow rectangle in Figure 3. You can see how open the area what that we were flying in, which is ideal.

Figure 3 is a map of the Priory property from a previous exercise but I choose it for this one as well to contrast some things.  You can see the contrast in vegetation cover in the areas where the red navigation points are compared to the yellow rectangle where we flew the demonstration flight.  The less large vegetation the better, at least for this flight.

Figure 4 is a photo taken from the ground of the yellow rectangle area in Figure 3.

Step 2 Mission Planning

Once you have your study area chosen and travel to that location the next thing to do is create your flight path and data collection mission. In order to do this we use a program call Mission Planner made by 3D Robotics. This software communicates with the auto pilot on board the UAV and tells it where to fly. There are many other parameters that can be set in this program as well such as altitude, flight speed, how often to collect a picture, and what to do at each way point ascend, descend, land etc. To draw a flight path you draw a rectangle with a mouse on the screen and then based on the parameter you have set Mission Planner fills in the flight grid. You can also manually enter the way points like I have done in figure 5. Once it creates the grid it will tell you an estimated flight time which is good to know because these vehicles do have a limit on flight time. Once you have your mission drawn you can get ready to fly with the next step.

Figure 5 is a screenshot of Mission Planner. I have manually drawn out a flight path for a mission over the soccer park here in Eau Claire.  You can see at the bottom of the image where you can set all the parameters for each point in the flight. If I were connected to an aircraft it would also tell me an estimated air time for this flight. It is important that these flight lines are close enough together to ensure the correct amount of image overlap. We shoot for 30% overlap and this program will adjust the flight path to accommodate that depending on which sensor you are using.

Step 3 Pre-Flight Checklist and Notes

This next step is the most important. Professor Hupy and I after some crashes and other growing pains in our research with UAV's came up with a pretty extensive checklist to go through prior to putting any of the UAV's in the air. Once the mission is created and the UAV is assembled going through the checklist is essential. We use the checklist shown in figure 6. We check the weather, all connections both frame and electrical, prop and motor check, battery and antenna check, controller and command center, battery voltage, number of satellites, mission sent to UAV, check takeoff area for people and then clear for launch. I haven't read the whole list but this gives you an idea of how many things we check. We check everything we can think of every time we fly. This is the golden rule of using UAV's. It is over looked many times and that leads to accidents which cost money and can damage property or even kill someone. Notice how the majority of this checklist happens before the aircraft is powered up, there is a reason for that. Once the UAV is powered up reducing the time someone is around it adjusting things the better. An accidental arming of aircraft could result in loss of fingers or worse depending on the platform. After every flight we take notes about the flight in a log book we have created as well. This is more to do with battery charging, post flight maintenance of the vehicles if needed and data processing. Figure 7 is a screen shot of the other excel sheet we use to keep track of all of our flight data.

Figure 6 is the pre-flight checklist we go through before every flight.  We do not fly until there is a check by each  row.  Like I stated earlier this helps us to fly safely which is many times overlooked because people think UAV;s are just toys and that they aren't dangerous. We know the dangers and use our checklists!

Figure 7 is the spreadsheet where we keep all the information about each flight. We record battery voltages, weather info, maintenance needs and suggestions for what to do better on the next flight. 

Step 4 Mission Execution

Once the the pre-flight checklist is complete the next step is to fly the mission. Part of the checklist is sending the mission to the UAV's auto pilot. Once this is done the aircraft is armed. After we are sure the area is safe we prefer to take off manually to about 10 meters height and do a stability and normal function test. We place it into loiter to see if it is functioning properly and can hold its position, if everything looks good it is flipped to auto pilot and it begins to fly the previously created flight path. During the flight there are a couple different jobs the crew flying the UAV need to perform. One is the pilot at the controls who has the controller in there hands and is piloting the aircraft. Another is the spotter who keeps an eye on the UAV at all times while it is in the air to make sure it is flying normally. The third person is the pilot in command. This person sits at the command station and watches the diagnostics on the Mission Planner screen (Figure 9). The person watching the laptop watches diagnostics like battery voltage, number of satellites, altitude, air speed, pitch, yaw, roll and that the aircraft is following the planned flight path. If anything looks suspicious this is the person who can abort a mission. When we flew the Matrix at the Priory for this activity we aborted a mission and safety landed the aircraft. I was at the laptop and saw that the UAV was deviating from the flight path and the spotter observed it acting rather strange in the air. I made the decision to say abort mission and the pilot at the controls, professor Hupy, said aborting mission and put the aircraft in RTL mode. RTL mode stands for return to launch. If at any time during the mission this switch is flipped the UAV stops whats it is doing and returns to where it took off from and lands itself. The mission may not have needed to be aborted however the class was relatively close to where the UAV was flying and as a safety precaution I decided to abort. 

Figure 9  is the display that the Pilot in Command watches as the UAV is in the air. You can see altitude, speed, battery voltage and other vital information is displayed here. If there is a catastrophic failure on board the UAV it will tell you on this display. If the GPS failed for example where it says DISARMED on the screen it would say NO GPS or GPS FAILURE in big red letters at which the mission would be aborted. 

Discussion

Stressing safety and common sense while flying a UAV is very important. UAV's are very useful and economic solution to perform a wide variety of tasks, however they get a bad reputation from people who use them improperly.I think this activity showed the class how important safety is and how much we are trying to stress it and emphasize it when we fly for research here at UWEC. I hope the class found this activity interesting, It can be a lot of fun flying UAV's and it is a good hobby to have I think but it is going beyond just the hobby and attaching cameras and sensors to the UAV to make it a system which can collect valuable data. When we flew this activity at the Priory we were using a special sensor made for us in the Twin Cities by a small private company. It contains two cameras, one RGB and one near infrared. With this camera we can take normal aerial imagery and look at vegetaion health at the same time. To give you an idea what the imagery looks like that we collected at the Priory I've included a few samples in figures 10 and 11. Figure 12 is a short video of the IRIS UAV.

Figure 10 is an image of  the data we collected during the aborted mission with the Matrix. The sensor we are using saves the images to a USB drive which is plugged into the command laptop where the images are quick mosaic together so that we can see if we have images of everything we wanted before heading back to the lab.

Figure 11 is a RGB image taken by the Matrix during its short flight at the Priory last week. You can see the parking lot and the students looking up at the UAV. Hundreds of images like this one get combined or mosaic to make up one big image of a study area.

 Conclusion

I really enjoyed this activity. Helping with the demonstration was fun too. I look forward to doing similar activities next semester with professor Hupy in his UAV class. It is rare to have a class like that offered at the undergraduate level especially when you can combine it with an already impressive GIS program. These classes will allow a student to learn how to go out and collect data with the UAV and then be able to their own data analysis with the GIS skills they are learning. This combination of skills will be very desirable to employers when the students graduate and they can continue to use their skills in this field for one of the hundreds of uses for UAV's and spatial data analysis. 

Activity 11:Navigation with a GPS device using a UTM Coordinate System

Introduction

This weeks activity was an addition to the activity last week of orienteering using a compass. In Activity 10 we used a compass to conduct an orienteering exercise out at the Priory which is just south of Eau Claire. This week Dr.Hupy wanted us to use a GPS unit to do a similar activity. He wanted us to see how helpful a GPS could be or how difficult it could be to use the unit because of lack of satellite signal and other issues caused by the elevation changes and heavy vegetation on the property. Dr.Hupy  also thought it would be interesting to have each group create their own orienteering course. He will be using these courses we created in the coming years for compass orienteering exercises. We used our same groups of three people from the previous weeks activity. Each person had a different task just like last week. This time one person was operating the GPS unit, a second was relating the GPS and navigation map and the third person was in charge of using the compass for orienteering and finding easier paths through the woods. Each group created and navigation their new course marking 5 trees with pink tape along the way.,

Study Area

The weather was again perfect for an outdoor activity. It was sunny with an air temperature in the mid to upper 70's and a slight breeze. The pollen content was high because trees and flowers we budding which made my allergies pretty miserable but otherwise it was a perfect day. (see Activity 10 for further study area details). We were in the same general area of the priory property for this activity however the groups spread out quite a bit to create a navigation course on each part of the property and not have them overlap too much if at all. Our course we created ended up being through a lot of very thick brush and brambles.Walking was very difficult even more so than the previous week on the property. Our course was more in the northern part of the property which has a very steep slope down into a much flatter area where our points are located. This was a much more mature forest than other parts of the property. The trees were much larger in diameter than other parts of the property and the tree canopy is pretty thick though this portion of the property which caused some problems for us with our GPS.

Methods

Before we went out we went out into the field for this activity there was some pre-planning and preparation that has to be done. One thing that had to be done was to set up a GPS unit to use in the field. For this activity like many others this semester we used a Trimble Juno GPS unit (Figure 1). This unit allows the user to load a whole map document onto the GPS. This is nice because that gives you a base map for reference as well as the ability to created layers or feature classes to the map while out in the field. We used our GPS unit mostly for keeping track and tracking what direction we were moving in and then collecting points where we taped the trees for our course. Another thing we had to do before going out in the field was to plot points where we would mark trees to create our course (Figure 2). In order to do this we went into an ArcMap document and created a new layer. It was a point file where we could place points wherever we wanted on the map. We tried to space our points about 150 meters apart to make the course a bit challenging. Once we had the layer created all we had to do is deploy the document to the Juno, When we got out in the field we looked at these points on the Juno and the little locator circle on the screen which tells you where you are and when the points we laid out were covered by this locator circle we found a large tree to place our tape and point numbers on for our course. 

Figure 1 is an image a Trimble Juno GPS unit. This is what we used to conduct this activity. This unit gives you the option of loading a whole map document onto it and editing that document right on the GPS.

 Figure 2 is the an image of the map we created with our new course location points on it. We loaded this document onto the Juno unit to aid in navigation to these points.

Before leaving the parking lot at the priory to mark our trees each group picked a part of the property to place there course in so that the courses did not overlap and most of the property had courses created on it. Once the areas were decided we plotted our points on our paper navigation maps just like we did in activity 10 the previous week. From this point on the activity this week was very similar to the one the week before. We used the compass to find our bearing keeping 'red in the shed' and 'following Fred' to find our new locations for a course. Like I said before we used also used our Juno unit to track the direction we were traveling and hep us get close to the points we previously plotted in ArcMap. This activity was also of test of how well the GPS units would do in the deep valleys and heavy canopy cover on the property. For the most part the GPS unit worked pretty (or so I thought) well which surprised me a bit. While in the field creating our course it looked liked the GPS had plenty of satellites and good signal but as I will explain later this wasn't the case. 

The process of places our points in the woods was easy. We got our bearing walked to the point we had on our Juno map and put a piece of pink marking tape around the tree. We then wrote the group number and point number on the tape so Dr.Hupy knew which group made each course and which points were part of each course. We places five points for our course and figures 3-12 are pictures of those locations.

Figure 3  This is the first point marked
 1:1 for group 1 point number 1.

Figure 4 This is the location of the first point.
It is on a rather large tree in a fairly open area.

Figure 5 This is the second point
marked 1:2 for group 1 point 2.

   

Figure 6 This is the location of the second 

point. It is on a medium size tree in another 

pretty open area.

Figure 8 This is the location of third point.
It is on a bigger tree with a large knot on
the side. This tree is in a thicker vegetation
area of the forest.

Figure 7 This is the third points
marked 1:3 for group 1 point 3.

Figure 9 is the fourth point in
 our course.It is labeled 1:4 for
group 1 point 4.

Figure 10 This is the location of the fourth point.
On another medium size tree in an open area where
it is easily visible.

Figure 12 This is the location of the fifth and final
point. It is fairly close to the parking lot and close to a
large clearing, It is on the only large tree in the area.

Figure 11 is the fifth and final point
 in the course. It is marked like the
other  1:5 for group 1 and point 5.

Discussion

As I mentioned before, when we were out in the field placing the markers and recording the GPS location of the 5 points I though the GPS was working well and collecting accurate data. When we got back and I put the collected locations of the new course points into ArcMap they are not accurate at all. There are 3 of the points that are in the general area but the other two points are way way out of place. Figure 13 is the map I created with the collected GPS points which are supposed to be where we marked trees for the navigation map but I would not trust these GPS locations at all. One reason for this awful GPS accuracy is the change in elevations throughout the Priory property as well as the thick vegetation canopy. The e combination of these two factors makes it very difficult for the GPS to record accurate information. The signal from the satellites gets bounced around off of trees and elevation above you causing large error in the collected data. For all of the locations where we collected this makes sense because we were down in a large gully that was at least 20 meters lower in elevation than the upper part of the property. I also mentioned that the area we were walking through had very thick vegetation. There was low ground vegetation just above our heads and another layer of tree top canopy. Both of these vegetation layers cause interference with the GPS readings. Another reason for possible error was that we could not get the GPS to collect points while we had our navigation map open on the unit. To fix this we manually collected the GPS locations for each point by looking at the GPS which gives latitude and longitude all the time for your current location. The lat long was collected in a cell phone memo sheet and later put into an Excel spreadsheet (Figure 14). Once it was in that Excel sheet it was then imported into ArcMap and assigned a coordinate system. This was much more time consuming and frustrating than it would have been if we had been able to just record the locations with the GPS itself and load the locations into ArcMap with a coordinate system and everything all set up.

Figure 13 This is a map of the location that we collected with the GPS of where our navigation course points were supposed to be. Points 2,3 and 4 are fairly close, within 10 meter or so of where they should be however points 1 and especially 5 are way out of place. This could be caused by high interference with the GPS signal or possible human error when we were collecting the points. The green box on the map is around the Priory property so you can see that the points were not even close to that property.

Figure 14 is the Excel table that I created with the Latitude and Longitude of the points we collected. What you see is not lat long but decimal degrees which are used with UTM system. Using an online converter I was able to take the lat long and get the decimal degrees for each point.

This data that we collected in figure 13 will most likely have to be recollected using a different GPS unit. In order to do this we will have to use our orienteering skills previously learned in this class to essentially run our own course we created and find our points. An accurate GPS location will be collected so that Dr.Hupy can actually use this course and know where the points are in the woods on the property. Figure 15 is a map showing the comparison of the plotted points and the GPS locations we collected. These points should be exactly the same or at least very close but they are not even close and that is why the locations need to be recollected.

Figure 15 This is just a map of both sets of points to show how far off our GPS collected points were.

 Conclusion

This activity was good because it made us use multiple skill sets we have learned during the semester. We used our knowledge of a Trimble Juno unit along with ArcMap, our orienteering knowledge from last week as well the process of creating a navigation map again with our plotted course points. Again the pre planning came into play more than other activities this semester and we see again how technology does not always make things easier. Human error and attention to detail were also important to the success of this activity. It appears as though our group may have made some mistakes in data recording but it is also possible that our GPS unit failed us. The only way to know is to take another GPS unit to the location and repeat the collection of the new course points. 

Activity 10: Field Navigation Using Orienteering Methods

Introduction

The activity this week made use of navigation maps the class made earlier in the year in Activity 3 The maps were used to navigate a course set out by Dr. Hupy at the University Wisconsin Eau Claire Priory. 5 points through out the wooded area of the property were found by using orienteering techniques which were learned when we constructed our navigation maps about a month and a half ago. Each group was assigned a different order of the 5 points so group wouldn't just follow each other around.

We were split up into groups of three which is the ideal number when doing orienteering exercises. Each person in the group has a different task which included the bearing finder holding the compass, a pace counter and a runner. Before heading into the woods we were given the UTM and lat/long positions of each point which we then placed on our navigation maps. All the groups started from the same location and took pictures of each stop to prove they had been there. The points were marked with pink tape around birch trees. 

Study Area 

The Priory (Figures 1,2) is a large piece of property owned by UW-Eau Claire about ten minutes away from the main campus and 3 miles south of Eau Claire. At the current time it is serving as a children s daycare center and dormitories for UWEC students. The majority of the property is heavily wooded and rather hilly which made navigation rather difficult. There is lots of buck thorn and brambles as well as downed trees and other obstacles to navigate around. While navigating between points we tripped and stumbled on logs and stumps and slid down steep embankments which made collecting an accurate pace count difficult. Although the terrain is somewhat challenging the other field conditions were perfect. It was a sunny spring day with hardly any clouds and a air temperature in the mid 70s. There was a slight breeze which kept us cool while trudging through the woods and the navigation area was dry with no mud to slip on. We heard horror stories of past years when this activity was done with snow on the ground so I am thankful that was not the case for our activity. The nice weather made this activity easier and more enjoyable.

Figure 2 This sign at the Priory entrance.

Figure 1 is a view of the front of the main
building on the Priory property where the child's
daycare and college  dormitories are located.

Methods

Upon arrival at the Priory Dr. Hupy gave each group of three people as set of 5 coordinates,each set being in a different order. Each group was then told to plot these points on the previously created navigation maps. The groups used UTM grids and meter increments given them to plot the points (Figures 3, 4). Our group right away recognized that the scale on the UTM grid was incorrect. The scale was too large and did not include enough decimal points to differentiate between each grid line. This significantly decreased the plotting locations accuracy which made the navigation to each point more difficult as well. We knew general ballpark of the points but we were off by roughly 10 to 15 meters on each point. Thankfully the trees did not have leaves on them and the pink tape stood out and was easy to see.

     

Figure 3 This is the 5 points we were given to plot. Text boxes and the bad scale on our map made it difficult to accurately plot the points, which did create problems for us later on in the exercise.  

Figure 4 is a map showing the Priory property. The red box is  where the navigation exercise was supposed to take place but as you can see the course ended up being slightly outside that area.

After each group had the points plotted Zach Hilgendorf, a classmate with knowledge on orienteering went over the a review of materials and basic procedure we had read about previous to coming in the field. He did a demonstration of how to properly use distance-bearing navigation to navigate from one point to the next.The first thing to do is assign each group member a job. Again the three roles are the bearing locator, pace counter and runner. In order to find a bearing you use a compass(Figure 5). You align the edge with the point where you are currently located and the next location. The direction of travel arrow on the compass always needs to be pointed at the point you want to go to next. Then spinning the dial on the compass and pointing it to true north on the map the bearing line will show you the direction of travel (Figure 6,7). Then remove the compass from the map and line the red north arrow up with the red arrow outline in the bezel of the compass. This is referred to as putting red in the shed. As long as you keep the red in the shed the direction of travel arrow will always point you to your next location failure to do so will lead to incorrect navigation headings and a lot of wasted time.

Figure 5 is an orienteering compass similar to the ones we used for this exercise. You can see all the different parts labeled above. Knowing how to use this device properly is the key to this exercise. 

Figure 6 shows a student setting
up the bearing on the compass. Setting north
 on the compass to true north on the map 
to get the bearing direction.

Figure 7 is Dr. Hupy giving instructions
on how to plot points to the groups of 3 and
giving final instructions before we headed into 
the woods.

Next the runner the is sent out to a set landmark or recognizable point in the exact bearing of the next location. Once the runner reaches this point the pace counter walks in a straight line to the runner recording how many paces he/she takes to get a rough estimate of distance traveled. Comparing this pace count to measured lengths on the map tells you approximately how far it is between the points. This process is repeated for each location.

Once this demonstration was over we were given the OK to start navigating to the first point. We started at a light pole just off of the parking lot (Figure 8) and set our bearing based on our map towards the first point. The runner was sent to the edge of the woods to a large tree in the bearing direction followed by the pace counter recording the distance. This was repeated again and in a short time the first point (Figure 9) was found on the edge of an open area. The location of this point was very visible so navigation right to the point was not necessary because it could be seen from a ways away. This navigation only took 5 minutes or so.

Figure 8 is the light pole from which each group
 began  their navigation to the other 5 points.

Figure 9 is a picture of point 1 proving that
we were there.

The next point was more difficult and the error of locations on our navigation map came into play. We followed the bearing and estimated the distance but overshot the point. We actually ended up finding point number three instead (Figure 10) about 20 minutes later. We then back tracked from point 3 to 2 which were fairly close together. We had missed point two the first time by a good 20 meters again because of the bad scale on our map. Point 3 to 2 (Figure 11) took about 10 minutes to navigate.

Figure 10 is a picture of point 3 proving that 
we were there.

Figure 11 is a picture of point 2 proving that 
we were there.

We then navigated from 2 to 4. Point 4 (Figure 12) was pretty easy to find. We had a good bearing and had a pretty accurate idea of distance but simply went too far. It was hidden over the side of a bank which we walked right past and failed to look down the embankment.  We only had to backtrack about 4 meters to find the point so we were very close with our calculations. Had we not overshot the point it wouldn't have taken as long to find but it took about 15 minutes because of that mistake.

Figure 12 is a picture of point 4 proving that we were there.

The final point (Figure 13) was rather difficult. Our bearing for this point was not spot on again caused by the map scale and this sent us into some very thick brush where our pace count got very skewed. For most of the navigation we figured that 85 paces would be close to 100 meters in distance but in this area it was more like 100 paces equaled 100 meter because of the small steps through thick brush. For this point we got our bearing and then split up and moved in a line in that bearing direction. This helped us to covered a wider area and increase our chances of finding the final point. This strategy worked. I crested a hill and down on the other side was the final point. The bad bearing and thick brush made this the longest navigation of about 25 minutes.

Figure 13 is a picture of point 5 proving that we were there.

Discussion

This excise had components that worked well and others that did not. It was quite difficult to use this technique in the heavily wooded and brush areas of the Priory. I did not expect it to be that difficult but all those obstacles really add up. It was hard for the runner to find a good distinguished position in line with the bearing because of all the brush and branches in the way. The pace count is what was effected the most by the terrain and study area features. Some places you could walk easily using the 65 paces per 100 meter measure but other places struggling through brush is almost 100 paces for 100 meters. Changes in elevation also greatly effected the accuracy of the pace count. Our map scale also made this exercise more difficult than it had to be. If we had had a better map scale we would have been more spot on with our bearings, cutting down on the time it took to find the points.

Even with these difficulties we were still able to find all 5 of our points in a relatively short time finishing before the other teams and finding points from previous years exercises that were still in the woods which Dr. Hupy was searching for using a GPS unit. 

Conclusion

This activity went quite well overall. The weather and lack of leaves on the trees were huge contributors to this result. The preparation in class for this exercise in previous weeks was also very helpful in the execution. All the groups found all of their points in order for the most part. This coming week we will be creating our own orienteering course at the priory using GPS units and Arcmap to plot the points on a map and then go into the woods find the locations and mark the trees for future classes to navigate. It will interesting to see how well the GPS units do in the woods with leaf cover and large elevation changes throughout the property.