Introduction
For this assignment the class was
given a real set of issues that have arisen and have been assisted with UAS. The
class was challenged to think like a geographer to solve these issues. The
scenarios that were given were detection of desert tortoise near a military
testing range, monitoring of power lines, observing a pineapple plantation for
health and harvesting, looking at a leaking oil pipeline in the Niger River
Delta and its impact on agriculture, and measuring a mining company’s mine and
how much is removed on a weekly basis. Solutions to these issues are to be
solved by using hypothetical UAS ideas.
Desert Tortoise
The desert tortoise is a
threatened species in the United States and is federally protected. This causes
problems for military testing facilities. The facilities must plan out all
exercises around the tortoise. This planning is usually in the form of
ground-based surveys. The survey area is large and ground based surveys are
cost ineffective and tedious. To make this easier we will use UAS to help out
with the surveying.
The desert tortoise’s habitat is
predominantly desert (ergo its name). The tortoise will build burrows for
shelter and protects them from the heat of the desert. These burrows are
usually found near vegetation, near or underneath shrubs or bushes. The burrow
has a distinct crescent moon feature which also be something to look for. These are the features that will be looked for
when using the UAS.
There are a few options that will
be used with our UAS. A fixed wing UAS
type is chosen over a rotary UAS. The choice was made based on a few
observations. These being the size of the area, and the potential for digital
modeling and Lidar. All these have been taken into consideration for the
project.
The definitive pieces on the UAS
will be a GPS and hyperspectral camera. The possibility for a Lidar sensor is
out there but that depends on the cost. The hyperspectral camera will include
the visible spectrum for the human eye as well as near-infrared and infrared
bands. The camera will take a picture every second with a high overlap so that we
have a high accuracy. The GPS will tag coordinates to our images for closer
observation. The flyover will take the images at each of the bands of the
camera.
Our first option is the
hyperspectral camera. As our flyover ends we will analyze the returned data
from our hyperspectral camera. The image will be viewed in a remote sensing
software program. What we are looking for is similar features throughout the
area. These features are the distinct shape of the burrow and the vegetation
that the tortoises usually build around. Once we have found these features and
similar features a supervised classification will be used. A supervised
classification is a process used in remote sensing in which a feature from an
image is selected and that feature returns a certain color signature. All areas
with similar returned spectral signatures will appear on the image. To verify
that these areas are burrows some ground surveying may have to be done for as
high an accuracy as possible.
The second option is to use a
Lidar sensor. The Lidar sensor will be placed on the UAS just like the
hyperspectral camera. The Lidar sends down light in a laser and collects the
return values. The return values are calculated by the time it takes for the
light to return to the sensor. This will give a 3D digital elevation model in
our end process with some very accurate features. Lidar can penetrate foliage as
well which will help with the location of burrows underneath the vegetation.
When we collect our data we can place the X, Y, and Z values into a GIS program
and get a 3D image of our area. With this we can see distinct features like the
burrows.
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| Figure 1: A Leica ALS70 LiDAR scanner. Similar to one that would be used when taking an airborne survey. Source for scanner |
These are the steps and processes
that would be taken to help out with finding these burrows. Multiple flyovers
may have to be done to assure for high accuracy. The best option would be to
use the hyperspectral camera plus small ground based surveys.
Power Line
Using a UAS for power line
inspection is a better solution than hiring a helicopter company to fly in from
a distant airport. Use of a UAS will cut costs that would be factored in for
fuel and transportation of the helicopter. The current process is to get as
close to the power line as possible and have a person lean out and capture
images. A technique which not only could result in poor images, but also cause serious
injury and even death. With a UAS the risk for human injury is eliminated.
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| Figure 2: Here is an example of a rotary wing UAS that can be used. The site attached has many option on what to use. Rotary Wing |
The rotary wing UAS uses blades
to navigate around. The blades propel the UAS up from almost anywhere. It does
not need space to gain speed like that of a fixed wing UAS. With the ability to
start from anywhere this eliminates the cost of having to fly in a helicopter.
The UAS can move around the power line and its components very smoothly due to
the stability of the blades. It can move in to take a closer picture of the
power line and can hover to allow for accurate pictures. A camera is placed on
the body of the UAS. It has the capabilities of taking video and still images.
The video can be relayed back to a controller for immediate viewing of the
condition of the power line.
The best option is to use a
rotary wing UAS with a high resolution camera with video and image capabilities.
The rotary wing is recommended because of the small area that is being viewed
and the means of having to be able to get within a close proximity of the power
lines which is helped by using the UAS’s hovering capabilities. We are
eliminating the risk of human injury by removing the dangers that are presented
with helicopter use. We are also eliminating helicopter transportation costs
that are factored in with the choice of airport and high fuel costs. The only
negative that is found is the timeframe that we are allotted. We must move
quickly because of the rotary wing’s small window for fly time.
Where to find rotary wing: Rotary Wing info
Pineapple Plantation
In consulting your plantation’s
operation it is my best recommendation that you would look into using the USGS’s
Landsat program. The Landsat program is a satellite operation that captures images
of the Earth using multispectral band imagery. The current satellite is Landsat
8 which captures an image every 16 days. That means that it flies over a spot every
16 days and takes that image. The imagery of Landsat is free to download, but
to use advanced systems one would need a photogrammetry/remote sensing software
program. I suggest Erdas.
To download an image of your
plantation you would navigate to the USGS global visualization viewer at http://glovis.usgs.gov/. Next is to find the
area that is your plantation. Once that is found I suggest choosing from the
Landsat 8 collection and setting your resolution to 240 meters for a closer
view. Adding that to your cart is done by highlighting your area and selecting
add at the bottom of the page. You must
register with the site first, which is free. The image will either be
downloaded directly or start to be process in which you would receive it at a
further date by email. The file will download a Zip file which needs to be
extracted. That will breakdown the Zip file into TIFF files. There will be 11
or so images files. If you are using Erdas you would want to add layers 2
through 10 and combine those as a layer stack. The image band that will work
best is the short wave infrared band which is band 6 and 7. These will show
your healthy vegetation as a white color. This will also help you to determine
when to harvest.
If the 16 day wait period is too
much for you I suggest that you used a fixed wing UAS. This will cost more, but
you will have a shorter wait time to view your plantation. I suggest placing a
multispectral/hyperspectral camera on the UAS if you choose this path. The
process is very similar to Landsat as the camera has bands as well.
The least cost effective path is
to use the free downloads from GLOVIS, but if you are looking at time
constraints using a UAS may work best.
Explanation of Landsat bands: https://landsat.usgs.gov/best_spectral_bands_to_use.php
Oil Pipeline
The Niger River Delta is one of
the most polluted waterways in the world and with nearby agriculture being
effected I suggest that using a UAS to monitor the situation is best. Knowing
that the area is also very dangerous this only backs up my suggestion. With the
potential of having your pipeline leaking I suggest that a rotary wing UAS be
used.
Since you are looking for the
leak in a specific area the rotary wing works best. The UAS can maintain
contact remotely within miles of the controller. This is a benefit as we know
of the dangers of the delta. The UAS operates with blades that balance the body
which usually holds a camera that can take pictures or record videos. The UAS
operates like helicopter which takes off vertically. Unlike a helicopter the maneuvering
is very simply as one can move freely around objects. This allows for movement
around the oil pipeline which allows for better observation for the like. Once
the leak is found then the UAS can take a video or images. I suggest a high
resolution camera for this task as it will best to have a small level of uncertainty
in this project.
I hope this has helped out.
Mine
I have looked at the options for
understanding the operation in which you are partaking. For this it is in my
best judgment that for your mine you should consider using a fixed wing UAS. I
understand that you do not have the funds for a LiDAR sensor. My suggestion is that
you look into a point cloud system on a UAS. Point Cloud is a system which
takes points of a surface and measures that surface using elevation.
I have suggested fixed wing because
of your spatial area. I know that this mining operation is quite large and
doing a quick fly over will suffice. With your fixed wing system I have
suggested a point cloud feature. By doing this on a weekly basis you can measure
how much you have removed by using a formula with the elevation difference. The
process should be done using a DEM or digital elevation model. This model will
be a 3D representation of your mine and again you can see what the changes are.
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