Introduction:
This lab three member group effort to better understand Unmanned Aerial Systems (UAS) by talking five real world problems. The problems required critical thinking and research. As most the students in the class were unframiliar with UASs, often called UAVs (Unmanned Aerial Vehicles), research into the components of a UAS was a must to understand how the drone could be used, ultimately, in the solution to the geospatial problems created for this exercise.UAV Overview
An Unmanned Aerial Vehicle (UAV) is an aircraft that has the capability of autonomous flight, without a pilot in control. Amateur UAVs are non-military and non-commercial. They typically fly under “recreational” exceptions to FAA regulations on UAVs, so long as the pilots/programmers keep them within tight limits on altitude (below 400 feet above ground level for recreational use) and distance. Usually the UAV is controlled manually by Radio Control (RC) at take-off and landing, and switched into GPS-guided autonomous mode only at a safe altitude.
- Operator must have a Civil UAS certificate
- Shows airworthiness proficiency
- Operator must have a Public UAS permit
- Enabling the operator to fly in civil air space
- NOTE: Current law prohibits the flying of UAS over airports, cities, and private air space.
What do you need to make a UAV?
1) RC plane, multicopter, or helicopter. Can buy them ready to fly,
including autopilot.
2) Autopilot, such as APM 2.6
- APM 2.6 autopilot: the electronics, including twin processors,
gyros, accelerometers, pressure sensors, GPS and more. Retail $179.
- APM 2 is an open source,
Arduino-compatible, pro-quality autopilot.
- APM 2 supports any kind of
vehicle with a one-click change of code.
- Available codes include:
- ArduPlane (fixed wing)
- ArduCopter (rotary wing)
- ArduRover (ground
vehicles)
- Provides an entire UAV
control system with scriptable missions with:
- 3D waypoints
- In-flight uploading of
commands
- Powerful ground station
software.
- Autopilot software:
- Arduplane: for fixed-wing aircraft
- Features included in arduplane
- Return to launch with a
flick of your RC toggle switch or a mouse click in the graphical Ground
Station
- Unlimited 3D GPS
waypoints
- Built-in camera control
- Fully-scriptable missions
- One-click software load,
and easy point-and-click configuration in the powerful Mission Planner.
NO programming required.
- Replay recorded missions
and analyze all the data with a graphing interface
- Supports two-way
telemetry with Xbee wireless modules.
- Point-and-click waypoint
entry or real-time mission commands while the UAV is in the air
- Fly with a joystick or
gamepad via your PC-no need for RC control
- Built-in failsafe will
return the aircraft in case of radio failure
- Arducopter: for rotary-wing aircraft
- ArduRover: for any ground- or water-based vehicle
4) “Payload,” such as a digital camera,
video transmission equipment, or other optional sensors.
Fixed wing craft:
Budget of craft - $1000 with: telemetry kit (wireless
communication), 3 batteries, and the OSD/FPV kit (enable the viewing of live streaming
video). http://store.3drobotics.com/products/3DR-ARF-APM:Plane
Advantages -
More forgiving (than rotary
craft) in the event of mechanical failure and/or pilot error do to their
natural ability to glide without power. Can carry greater payloads
for longer distances on less power. Have longer flight time than the helicopters (Gas: around 10 hours, Electric: around 45-60 minutes).
Disadvantages -
Cannot hover over one spot,
meaning they cannot provide the same level of precision, for point
specific scenarios. Cannot perform vertical
takeoff
Helicopter – Single Rotary Craft
About:- 1-2 blades to generate lift
- Maintain directional control by varying blade pitch
- Gas or electric
- Medium range
Advantages
- Vertical liftoff with ability to hover.
- This allows for increased detail in hard to reach situations.
- Real-time feedback
- Can carry various sensors:
- Day
- Low-light
- Night vision
- IR sensors
- Strong, fast and efficient
- Some can be weatherized
Disadvantages
- Range: limited on payload
- Fuel Type and flight time:
- Electric: 20min - 90min
- Gas: 4-5 hours
- More
limited flight time and payload capacity when compared to a fixed-wing
craft
Multicopter
About:- Excellent for surveying
smaller areas at high levels of detail.
- Can hover in place when greater detail and zoom is required.
- Utilizes differential thrust management of independent motor units to provide lift and directional control.
- Simple mechanical design, large degree of design flexibility.
- Allows many options for mounting payload.
- Carries a decent payload in strong wind conditions.
- Multiple arms decreases the risk of serious injury.
- Battery life ~20 minutes max.
- Typically, more arms = less battery life
The copter compensates for gusts of wind by tilting automatically against the direction of the disturbance.
Multicopter system: http://copter.ardupilot.com/wp-content/uploads/sites/2/2013/07/copter-diagram.png
The Quadcopter is simplest, most popular, and most reliable. If you are inexperienced, start small. The quadcopers are easier to fly, light, tough, relatively safe, and survive mishaps well.
Multicopters are highly stressed systems and require that all components match compatibility:
Projected weight, performance, flight time, and payload require balancing to achieve good results.
Frame size, weight, power requirements, and payload are important to consider
Good starter: http://traxxas.com/products/models/heli/6208qr1
Highly recommended system complete with pre-mission software: http://store.3drobotics.com/products/iris
Scenarios:
#1
(Brielle ) A military testing range is having problems engaging in
conducting its training exercises due to the presence of desert tortoises. They
currently spend millions of dollars doing ground based surveys to find their
burrows. They want to know if you, as the geographer can find a better solution
with UAS.Questions to ask:
Where are the turtles?
herbivores, feed on grasses/wildflowers/cactus pads (http://www.defenders.org/desert-tortoise/basic-facts)
97% of borrows associated with shrub vegetation (FS)
Deep
burrows under large/near large boulders (FS)
95% of
life spent in burrows (https://www.desertusa.com/reptiles/desert-tortoise.html)
The presence of soil suitable for digging burrows is a
limiting factor to Desert Tortoise distribution (desert usa). Soil that crumbles
easily during digging and is firm enough to resist collapse (http://www.fs.fed.us/database/feis/animals/reptile/goag/all.html#Soil)
Commonly use sites with sandy loam soils with
varying amounts of gravel and clay (FS). Avoid sands (FS).
Dig basins to collect rain water (desert usa)
What sensors can locate the burrows/turtles?
How big
are they? 3-6ft deep (defenders).
How are
they capable of being located? temp? Vegetation
When
turtles move, how far? Do they stay in one burrow?
Stay in
burrows in torpor from November-February (defenders)
Most
active in Spring (defenders)
Is burrow
count accurate to turtle numbers? Single tortoise may have dozens of borrows
across range (desert usa)
Do
turtles return to same burrow? no/possible
Where are
the closest natural areas?
How large
is the testing range?
Are there
multispectral satellite images available?
Are
training exercises continual or scheduled for certain time spans?
How often
are the exercises conducted
How often
do the tortoise surveys need to be done
Possible
solutions:
Landsat-Resolution
isn’t fine (60m)
NIR
scanner for vegetation detection Landsat 8 ban; Landsat(4 or 5) band4
Thermal
image for burrow entrances? Landsat(4 or 5) band 6; Landsat 8 band 10/11
Soil
maps- Landsat(4 or 5) band 5 or 6
Fixed wing craft-large area
NIR
scanner-vegetation detection
Thermal
imager-burrow entrances
Short-wave
infrared scanner-soil signatures
Duration:
due to large area, longer duration; gas powered more reliable
#2 (Tim) 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.
Questions
to ask:
How often do problems occur along the power lines?
How much does it cost to get the helicopter out to inspect the line? Are the
lines accessible to ground crews to get close enough quickly enough? What type
of area are the power lines in, populated or rural?
Possible
solutions:
A multi-copter would be a good option to perform
this task. A ground crew with the multicopter would get close enough to the
power lines that they wish to examine in order to use a multicopter The UAV
multicopter should be installed with a high quality camera and should be able
to operate at a relatively low noise level to prevent disturbing wildlife or
cattle that may be in the area. It would also be advantageous to have some way
for the copter to detect changes in the electrical field around it so it could
detect anything that may be wrong with the power lines.
The
multicopter at the link below is one of the standard and typical multicopters
used for this type of work. It has a high payload capacity (3kg) for high
definition imagery, has it’s rotors covered for safety when flying near power
lines, is equipped with excellent crash/accident avoidance technology such as
its “coming home” function, is very stable when holding position for excellent
imagery, and comes with some of the best pre-mission programming. It will cost
around $30,000 per multicopter but this will pay off in the long run when
considering that the company is paying thousands upon thousands of dollars EACH
time the helicopter has to go out to check the power lines. It’s a cheap start
up cost but will pay off in the end, as this is a very reliable model.
It
may be a good idea to have a UAV helicopter along as well, this way, if a power
line needs to be looked at rapidly due to some sort of emergency, the
helicopter drone can be launched from further away due to it’s longer range.
The same considerations regarding weight, noise level, image quality, and
maneuverability would need to be taken into consideration for the helicopter
drone as for the multicopter.
The Black Eagle designed by steady copter is a solid option that can hover within 5 meters of the power line and has a 3kg capacity. It will cost around $10,000. This start up cost is less than that of the Aibot x6 multicopter above so this may be a better option if the company decides that it would be too difficult to get close to the power lines.
Both
the Aibot multicopter and the Black Eagle helicopter UAVs would be good options
for this job. I think that recommending both to the company and pointing out
the benefits/drawbacks of both would be a good option.
#3 (Tim) 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.
Questions
to ask:
What type of area is the pineapple plantation in?
What is currently being done to assess these
problems?
Possible
solution:
UAV helicopter equipped with NIR camera sensor
which will detect higher reflectance of healthy vegetation. This UAS would
require a pre mission software that would allow it to track and cover the whole
field recording data spatially. Ideally this would be done during the day when
there is the highest amount of NIR reflection.
A gas helicopter would be a good option for this,
perhaps the Sniper with a NIR camera mounted on it. This is because the field
is too large for the flight time of a multi-copter but needs the focus and
maneuverability of a helicopter. http://www.uavsi.uk.com/docs/UAVSI_SNIPER_Heli-UAV_Brochure.pdf
The near infrared camera can be used to tell
whether vegetation is healthy or not. There is a high range of difference in
the NIR (720nm-1300nm) reflectance of healthy vegetation and unhealthy
vegetation. Healthy vegetation reflects significantly more NIR waves. This
means that in NIR images the healthy vegetation will appear more prominently
than the unhealthy vegetation. http://flightriot.com/nir-and-vegetation/
Pineapple plants are read to harvest when they are
in the late stages of their development. This means that they have over 1/3 of
their peel as a yellow color but they haven’t lost all of their green yet.
NIR reflection has been tested to see whether or
not it can be used to detect ripeness of a plant, as the plant gets riper, the
NIR tends to decrease. This fact combined with the fact that when pineapples
are ready to harvest they shouldn’t be ripe yet and shouldn’t be harvested
until their skin is 1/3 yellow and 2/3 green can help determine the best time
to harvest the pineapple. Using a multi-spectral approach with both visible
wavelengths to try and determine color and NIR wavelengths to determine health
and whether the plant is ready to harvest.
How big
is the range of possible leakage in the pipe?
Will
there be any restricted areas to avoid?
Risk of
fire hazard?
Will the
UAS be flying over any populated areas?
What time
of year will the surveying take place?
Possible solution:
Because
this is dealing with such a large area you will need a UAS with a large antenna
which will allow for longer flight time. Also, you will be sensing expansive
areas, without the need for high definition, so the precision brought on by a
multicopter is not needed. The best type of craft for this mission would be a
gas powered fixed-wing craft. Given the fact that they are recruiting you from
half a world away, it is fair to assume that the $1,000 price tag for an
intermediate plane is not to high.
The main
sensor on the plane would be a small thermal imaging camera, to fly
autonomously along the pipeline, just after sunset, to record the thermal
images of the ground, from which one can deduce the thermal heat capacity of
the ground, around the pipeline.
Just
after sunset, there will be a drop in temperature, just as there will be an
increase after sunrise, and one can interpret the thermal images, to estimate
the heat capacity of the ground. If these images are taken once a day, one
should be able to detect leakage from any of the pipeline joints because of the
change in heat capacity of the ground given the event of a leaking leaking
joint.
One
should have a time dependent view of the changes. This suggested approach rests
on the heat capacity of the oil and the ground being different from that of the
ground alone.
What is needed to accomplish this?
What is needed to accomplish this?
- Construct a 3D computer based thermal model of the buried pipeline and surrounding soil.
- Heat capacity of properly functioning pipeline
- Thermal conductivity data. For the materials (land, water, vegetation, etc.) in the immediate areas to the pipeline.
- Would also need to monitor the temperatures at various depths along the pipeline. To determine the heating effect of the sun’s rays during day time. The rate of cooling. As a function of depth and location along the pipeline, during the night time.
- With a combination of the computer model and measurement information, one would relate the minimum sensitivity of a thermal imaging system to the size of the leak that could be detected. The measurement information would also be used to determine the best time to perform the thermal imaging, likely, just after sunset.
Barnard
Microsystems. A Suggested Way to Detect Oil Leakage. http://www.barnardmicrosystems.com/UAV/pipeline_monitoring/detect_oil_leakage.html
Questions
to ask:
What is
your budget for the project?
How
expansive is your mining operation?
Is your
mine an open pit mine?
- Install the Photosynth application
- Install Image Composite Editor
- Use SynthExport to extract the point cloud as well as camera parameter data of your synth on Photosynth.
- Supported Point Cloud formats
- OBJ (no vertex colors stored)
- Polygon file format (ASCII and binary)
- VRML
- X3D
- Use a product like Meshlab to generate a mesh surface from the point cloud.
Once you
have created a 3D surface, say in ArcMap, you could use the “Surface Volume”
tool (3D Analyst Extension).
The Surface Volume tool calculates the area and volume of a raster or TIN surface above or below a given reference plane.
The Surface Volume tool calculates the area and volume of a raster or TIN surface above or below a given reference plane.
Using this tool you could set the plane at a control depth; which, would stay the same each week. Then you would calculate the volume of the ground each week. Theoretically the volume of that ground would decrease each week as the ground is excavated. This change in volume would be the amount of material mined each week.
Take an abundance of photos with sufficient overlap (>60%)
Photosynth picks out identifiables points that are common to multiple photos, then uses the different distances, angles and relative sizes of the points in the images to work out the 3D arrangement of the actual points on the real object, which it generates a point cloud from. http://diydrones.com/forum/topics/making-digital-elevations
The
number of photos taken from a fixed-wing plane may not be enough to get a dense
mesh.
Using a kite might actually work better.
Perk of using a Kite:
You can collect data as long as the wind is blowing
Much cheaper than buying the small UAV and all the systems that go along with it.
Imagery must have at least 60% in-track overlap and should have at least 40% cross-track/orthogonal overlap. Imagery must be shot in sequence. Imagery includes overlap.
Sources used in research:
Drone Mapper, Hints & Tips
Making Inexpensive Digital Elevation models
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