CHAPTER TWO
AUTONOMOUS VEHICLES (AQUATIC ROBOTS) USED IN MONITORING AND DETECTING HARMFUL ALGAE BLOOMS
There are some autonomous plate forms used for detecting and monitoring harmful algae bloom. These plate forms can be equipped with a wide range of sensors and varying levels of autonomy. Environmental sensory networks will often employ a combination of severs different plate forms to
achieve the best results (Mellinger, 2012). Some of this autonomous plate forms are: Autonomous under water vehicles (AUVs), Autonomous surface vehicles (ASVs), Unmanned aerial vehicles (UAVs), sensors etc.2.1 Autonomous Underwater Vehicles (AUV)
Autonomous underwater vehicles (AUV) are remarkable machines that revolutionized the process of gathering ocean data. AUVs come on multiple shapes and sizes to fulfill a wide verity of roles from oceanographic data collection to ship hull inspection the torpedo AUV is the standard design for oceanographic work where straight line performance is prioritized over maneuverability (Lucieer, 2011). This robotic device is driven through the water by a propulsion system, controlled and piloted by an on board computer. Sensors on board the AUV samples the ocean for harmful algae bloom as AUV mores through it, providing ability to make both spatial and time sense measurements AUV travels underwater without requiring input from an operator. With miniature sensors and computers allow the AUV to be equipped for missions on including undersea archeology and exploration, environmental monitoring and acoustic surveillance (Lucieer, 2011). The AUV from ocean server are primarily used for measuring water properties with their in-situ chemical sensors. The chemical sensors on the AUV are able to measure turbidity, dissolved oxygen, rhodamine, chlorophyll, blue-green algae (phycoerythin), pH, temperature and salinity. One man-portable ocean server 1yer 2 a six diameter torpedo shaped and found at on end of the can operate for several hours in shallow (<100m) coastal waters while equipped with standard sensors such as a CTD or ADCP. At the other extreme are deep water AUVs capable of operating several thousand milers deep for a day or more, these AUVs can carry advanced button scanning sonar or tow multi-transducer arrays (Curton and Bellinghan, 2001).
2.2 Autonomous Sure Ace Vehicles (ASVs)
Autonomous surface vehicles (ASVs) are for operations in habours, lakes and shallow coastal zoned. They provide pay load and computation capabilities similar to larger AUVs while being much cheaper and easier to operate capable of speeds of several meters per second, they can operate on much stronger currents than many AUVs (Achtelik, 2009). Their case of use combined with availability of RF communications also makes then an ideal plate form for the development of control and autonomy software. The ideal of monitoring several metes of ocean water with AUVs and UAVs in constant communication led the development of swordfish ASV. The scout (surface craft for ocean graphic and under a testing) is an ASV built around a standard kayask hill. Initially developed at MIT on 2004, the scout was designed independently or in conjunction with AUVs (Curcio, 2005). It has since been commercialized and had been used in wide variety of field trials from ocean graphic studies to experimental hydrodynamic research (Zheng, 2009). Equipped with a winch, the vehicle can deploy oceanographic sensors a various depths a providing an AUVs data product for shallow waters without the usual hassle and expense (McGillivary et al., 2006).
2.3 Unmanned Aerial Vehicle (UAV)
Unmanned aerial vehicle (UAV) can fill the gap between remote sensory satellite systems and in-site observation plate forms. They can also provide surveys of inaccessible or rough terrain UAVS can target biosecurity application that can be observed only above or that require sampling of areca environment.
The primary types of UAV are fixed wing rotary wing and lighter than air (LTA). LTA autonomous airship have potentially the longest mission times and can have for extended periods of time over an area of interest, however they more at slow speeds than air planes or helicopter. Fixed-wing UAVS tend to be the fastest alternative and here potentially the longest mission range but can neither hover not operate very close to the surface. Helicopter, due to their high controllabity, can be used for prose nap-of-the-earth flying as well as hovering but have shorter mission time and ranges UAU plat forms for civilian use cost typically one to two orders of magnitude less than manual aircraft in their category and are also much chapter to operate. As a result UAVs are being deployed in increasing numbers around the world for a growing number of applications. UAVs operate over a spatial scale of the order of 1-10 resolution of centimeters to tens of meters depending on the flight altitude and the sensor pay load. All three of UAV can perform surveys of areas of interest at regular time intervals (typically minutes to hours) and airships and rotary-wing craft can hover over a given area for longer prior as of time to allow persistent temporal monitoring of a process of interest. Sensor pay loads on UAVs for biosecurity survey can red-green-blue (RGB), thermal, multispectral and/or hyper spectral imaging sensors, lidars and/or radar for characterization of the 3D environment below the aircraft environmental and weather sensors and a combined GPS and inertial navigation system (INS) unit for accurate localization of sensor observation. High value applications of UAVs in biosecurity survey such as limonlogical and var-shove ocean surveys for harmful algal blooms (HABS).
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