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September 2010, these unmanned ground vehicles
had performed 125 000 tasks, including suspicious
target identification, road cleaning, and positioning
and removal of improvised explosive devices
(IEDs). The U.S. Army, Navy, and Marine Corps
explosive demolition teams have used unmanned
ground vehicles to detect and destroy more than 11
000 IEDs.
From 2010, the development of UVs entered a
new phase because many automobile manufacturers
and IT companies started to switch their attention to
this field. Mercedes-Benz, BMW, Volkswagen, Ford,
and independent prototype companies have launched
new R&D programs for UVs. Google’s UVs
(Markoff, 2010), which are the representative
models, are already on the road legally in California,
Nevada, Florida, and Michigan, USA. On December
22, 2014, Google officially announced the
completion of the first fully functional prototype of a
UV, and started official road testing in 2015. Since
then they have tested vehicles over 1.4 million miles.
Tesla’s UV with wireless firmware upgraded to
version 7.1.1, has accumulated 780 million miles of
test data, and can collect one million miles of data
every 10 h. Mobileye, an Israeli intelligent driving
technology equipment manufacturer, announced
early in 2013 that the company’s equipment would
be available for automatically driving a car on the
road in 2016. Its C2-270 intelligent traffic warning
systems, a successful application of the company’s
products, would be launched with its product
upgrade. Apple also started an internal development
program called ‘Titan’.
Chinese companies have also been attracted to
the boom in UVs. The Chinese search engine giant
Baidu has released its first UV-related project. In
cooperation with the Hefei Institutes of Physical
Science, the Guangzhou Automobile Group has
developed a renewable energy UV. Other native
Chinese automobile manufacturers such as BYD,
Yutong, and SAIC are also actively exploring the
development and industrialization of UV
technologies.
Despite the progress in UVs, there are still
considerable problems that need to be solved,
including situational awareness in real-time
environments, intelligent decision making, high-
speed motion control, precision driving maps,
unmanned system evaluation and assessment
methods, and system reliability.
4 Trends in unmanned aerial vehicle
development
4.1 Overview of unmanned aerial vehicles
An unmanned aerial vehicle (UAV), commonly
known as a drone, is an unmanned aircraft system
(Wikipedia, 2016a). Therefore, it is a typical kind of
advanced autonomous unmanned system. In general,
UAVs can be used to collect data and perform
monitoring, surveillance, investigation, and
inspection (Nagaty et al., 2013). According to their
different areas of applications, UAVs can be divided
into two major categories, civilian and military
(Valavanis, 2007).
Military UAVs, a kind of weapon, are used
mainly for surveillance, reconnaissance, electronic
countermeasures, and attack and damage assessment
in battles. Compared with military uses, civilian
UAVs have a wider range of application including
environmental monitoring, resource exploration,
agricultural surveying, traffic control, weather
forecasting, aerial photography, disaster search and
rescue, and transmission line and railway line
inspections.
4.2 Status of military unmanned aerial vehicles
UAVs were first introduced by the U.S. military
during World War I (1917) (OSD, 2002). Military
requirements gave birth to a variety of UAVs. Many
of them were involved in wars, such as the World
War II, the Vietnam War, the Middle East Conflict,
and the Kosovo War, in which they played important
roles (Wikipedia, 2016b). These wars promoted the
rapid development of UAV technologies. So far, the
most advanced and well known military UAVs
include the X47-B, Predator, Global Hawk, and Fire
Scout, which are already capable of autonomous
takeoff and landing, and following autonomous
flight routes. Some of them can partly adapt to flight
faults or condition variations. However, according to
the ‘Unmanned Aircraft System Roadmap 2005–
2030’ published by the U.S. Defense Department in
2005, the current autonomous level of military
UAVs is lower than level 3 (OSD, 2005). They do