Natural disasters strike unexpectedly, often taking countless
lives and causing significant economic impact on the affected areas. Time is a
critical factor when it comes to the emergency recovery missions. Unmanned
aerial systems (UAS) applications during disaster recovery missions offer many
valuable advantages for the emergency personnel. UAS has been utilized in several
search and rescue missions during hurricane recovery efforts (Nitti, 2011). The National
Astronautics and Space Administration (NASA) together with National Oceanic and
Atmospheric Administration (NOAA) employed a Global Hawk UAS to collect data on
hurricane Matthew, which recently affected the east coast of the United States (Vanian, 2016). The Ikhana UAS
was deployed during wildfires in California. It was collecting temperature data
and mapping fire locations. This UAS transmitted fire spot information to
multiagency management centers and emergency workers on the ground helping the firefighting
operations (National
Astronautics and Space Administration [NASA], 2010).
UAS can also serve as a communication relay or wireless “hot spots”
in case of communication infrastructure damage in the area. In fact, Verizon
has tested this application utilizing a UAS as a mobile hot spot for its cell phone
network. This capability can help first responders communicate and have access
to online resources. This technology is even more valuable in remote locations
where the wireless is damaged or destroyed or even in areas that currently have
wireless service. (Hamblen,
2016).
For this paper the author selected the UAS that can be used in hurricane
recovery missions. First, let’s discuss some of the baseline and derived
requirements for this type of UAS. The time line for design, development,
testing, and deployment of this UAS would be approximately one year. The
vehicle platform should be small enough to be easily transported to the
disaster area and launched on the moment’s notice. It will require high definition
still camera and video sensors to provide the recovery workers with complete
picture of the area. The sensory payload would also include a thermal sensor
and a night vision sensor to aid in location of stranded persons during poor
visibility and low light operations. The UAS should be capable of providing
imagery of the area supplemented with the GPS location tags for quick position
reference. The vehicle should be able to withstand moderate wind gusts since it
may need to be deployed immediately after storm passage. Therefore, the base
and derivative requirements will include the following parameters:
1.
Air vehicle
element shall be able to house all required systems, payload equipment, and
provide sound aerodynamic flight capabilities.
1.1 The
UAS shall be able to operate at altitudes of 300 feet above ground level.
1.2 The
UAS shall be able to offer one-hour endurance.
1.3 The
UAS shall be able to cover a range of 3 nautical miles.
1.4 The
UAS shall be able to hover.
1.5 The
UAS shall be hand launched.
1.6 The
UAS shall be able to perform landing without requiring runway or approved
landing area.
1.7 The
UAS shall have a sufficient physical dimension to incorporate all required
payload equipment.
1.8 The
UAS shall be equipped with sufficient power system to sustain flight operations
and support payload equipment.
1.9 The UAS shall be able to operate during
wind speeds of 30 miles per hour.
1.10
The UAS shall be able to withstand wind gusts up to 30
miles per hour.
1.11
The UAS shall be able to be prepared for launch within
20 minutes.
1.12
The UAS shall feature a robust design for operations in
the adverse weather condition.
1.13
The UAS shall have a waterproof design to protect the
vehicle and sensors from the elements during operations in precipitations.
1.14
The UAS shall incorporate both autonomous and manual
operational capabilities.
2.
Payload element.
Payload sensors shall provide means for an area inspection and for victim
location.
2.1 The Payload shall be
capable of color motion video recording up to 300 feet.
2.2 The Payload shall
incorporate an infrared (IR) sensor.
2.3 The Payload shall
incorporate a thermal sensor.
2.4 The Payload shall
utilize the main power system of the UAS.
2.5 The Payload shall be
able to communicate acquired data via datalink to the ground control station
(GCS) in real time.
3. The communication (data-link) shall provide a robust connection
between the UAS and the GCS. It shall enable The UAS to receive commands from
the GCS and downlink sensory data and UAS status to the operator.
3.1 It shall incorporate
lost- link contingency procedures.
3.2 It shall be able to provide uninterrupted communication within
a 3 miles’ radius.
3.3 It shall provide a means of real-time video transmission to
the GCS.
3.4 It shall provide a means of still pictures transmissions to
the GCS.
3.5 I shall provide real-time vehicle telemetry and “health”
status.
3.6 It shall be powered by the UAS power system.
3.7 I shall accommodate a means of redundancy for the C3 systems.
Now that base and derived requirements are defined, it is
important to discuss some of the testing requirements that can be used to
validate and verify that base parameters have been met (Torun, 1999).
1.
Testing requirements.
1.1 Vehicle
element
1.1.2 Test aerodynamic
capabilities of the UAS using wind tunnel testing.
1.1.3 Test wind
tolerance, gust tolerance during all cruise, takeoff, and landing conditions in
the wind tunnel.
1.1.4 Test if the
platform is waterproof using various precipitation levels.
1.1.5 Test the take-off
and landing capabilities.
1.1.6 Test the hover/
orbiting capabilities of the vehicle.
1.1.7 Test that the vehicle
platform will have sufficient space for all sensor payload and subsystems by
physically incorporating each system into the vehicle.
1.1.8 Ensure proper
center of gravity location.
1.1.9 Conduct manual
flight testing in a real- world scenarios.
1.1.10 Conduct automated
flight testing.
1.2 Payload
1.2.1 Bench test payload
equipment to determine if the UAS power system will provide sufficient power
for the payload operation.
1.2.2 Test various
commercial-off-the-shelf (COTS) sensor options available and compare their
size, weight, and power requirements.
1.2.3 Test the GPS data
tags accuracy using predetermined locations on the ground.
1.2.4. Test the payload interoperability
with C2 and the data-link subsystems.
1.3 Communications (data-link).
1.3.1 Test the communication
range of the UAS in different geophysical setting, such as flat terrain,
mountainous areas, hilly areas to determine how the topography will affect communications.
1.3.2 Assess lost-link
procedures and vehicle performance during lost communication scenarios.
1.3.3 Test functionality
of the redundant communication channels.
1.3.4 Test the procedure
for switching to the redundant means of communication.
1.3.5 Test data uplink
channel volume and speed of communications.
1.3.6 Test down-link
channel volume of speed of communications.
1.3.7 Test if
communication subsystem has sufficient power provided from the vehicle element.
Now, that testing requirements have been established, it is
important to note, that the UAS test site may need to be reserved well in
advance to enable on-time testing and ensure seamless transition between
design, development, and testing phases of the project (Austin, 2010). It is important
to develop a time line for the design project, that will include various stages
of the design and the time allocated for each phase (Figure 1). It is
advantageous to maintain a detailed record of any change made during the design
process (Gurd, 2013).
Traceability is extremely important, since even a minor change in any of the
UAS sub-systems may affect other system design and may compromise the entire
project (Austin, 2010).
Also, it is imperative to assign specific tasks to each personnel to maintain
accountability. Each person must also define
a level of authority thought the entire project to ensure a timely completion
Figure 1. The UAS project planner and timeline. This chart was created
using a Microsoft Excel Gantt Chart.
Another important step is the UAS certification. The appropriate regulatory agencies, such as
the Federal Aviation Administration (FAA) should be contacted in the early
stages of the UAS design. The assigned UAS company representative shall
maintain close communication with the Agency in order to receive any feedback
and incorporate any required changes into the design process to help speed up
the certification process after project completion (Austin, 2010).
Since hurricane recovery missions are never standard, the UAS
platform shall have a modular design that allows it to incorporate
interchangeable payloads (Torun,
1999). It is advisable to use COTS products to meet this requirement. COTS
products can present a significant advantage for designers especially in the selection
of sensors and camera equipment. COTS will save time on development, and less
expensive than customized payload design. Another advantage of modular design
and the use of COTS systems is the possibility of future upgrades and further
customization. As technology progresses and sensor capabilities improve, new
payloads may be incorporated in the existing UAS platform.
As we can see, the UAS design process is a complex task, which
requires careful planning, constant control, continuous adaptation to changes,
and rigorous testing. After the UAS is built, tested, certified, and released
to the customer, it will need to be supported, maintained, and possibly
upgraded to maintain its efficiency, reliability, and safety. By carefully
outlining the base and derivative requirements, including accountability,
traceability and adhering to the timeline, the UAS project will be successful
and produce a marketable product.
References
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