Thursday, March 21, 2019

Sensors used in UAVs


Sensors used in UAVs are mostly categorized into Navigation Sensors and Sensors used for missions. Most of the sensors used for navigations on UAVs comprise of sensors such as Global Navigation Satellite Systems (GNSS) which includes the Global Positioning Systems and the Inertial Navigation System. GPS and INS complement each to the point that they are the preferred sensors for the majority of autopilot systems (Mejias, Lai, & Bruggemann 2015)
Other sensors used for navigations or surveillance include the Electro-Optical (EO) Sensors and Radio- Wave Sensors
Electro Optical (EO) Sensors;
i.                    Visible Spectrum: These are either digital still cameras or machine vision webcams that are used to take pictures or provide a continuous stream of images respectively. This type of sensor cameras is mostly used in aerial photography.
ii.                  Infrared sensors:  Infrared cameras that are sensitive to light at a long wavelength and form images using infrared radiation in the spectrum at wavelengths of 14,000nm.
iii.                Hyperspectral Imaging:  these are sensors that acquire image data simultaneously in multiple adjacent spectral bands. This type of sensor is mostly used for identifying different compositions of materials
Radio- Wave Sensors
Airborne Radio Detection and Ranging (Radar) and Light Detection and Ranging (Lidar) systems are used to determine the range, altitude, direction and speed of objects by measuring signal return time of transmitted controlled radio pulses. Radar sensors such as the Ground Proximity Warning Systems (GPWS) have been widely used in the aviation world. Radars are also recently being used in the automotive industry for collision warning systems. ( Mejias, Lai, & Bruggemann 2015)
Exteroceptors (External) and Proprioceptors(Internal)
Exteroceptors are sensors that allow the robot of unmanned systems to perceive or interact with its environment whole Proprioceptors sensors measure the internal kinematic and dynamic parameters of the unmanned system. Such parameters include the amount of torque exerted by the actuator. Exteroceptors are grouped into contact and non-contact sensors. The contact sensors perceive their environment by touching the objects and shaped in its environment while non-contact sensors obtain information about its environments without physical contact. Such non-contact sensors include pneumatic sensors, ultrasonic sensors, and optical sensors (Gupta, Arora, & Wescott, 2016)
Sensor Review
 https://ieeexplore-ieee-org.ezproxy.libproxy.db.erau.edu/xpls/icp.jsp?arnumber=4772754
For the sensor review, I have selected the journal article that uses the Miniature Strapdown Inertial Navigation System (mini INS) with inertial microelectromechanical systems (MEMS) for control of different UAVs in the autopilot mode. Inertial Navigation System sensors as noted earlier are used for navigation. The Miniature Strapdown Inertial Navigation System (mini INS suit this mission as it is low cost with small overall dimensions and consumes very low power. The sensor can provide the required accuracy of determining the attitude, position, and velocity of the UAV. The use of the inertial system as the main component of the autopilot provides the required flying accuracy with the capability of UAV destination to the desired waypoint at a given time and tracking the predefined path. (Kortunov, Dybska, Proskura, & Kravchuk, 2009)
The disadvantage of using this system in an autonomous mode is hampered since the instability of MEMS sensor characteristics causes fast accumulation of errors in the determination of navigation data. The effective approach to solving this problem is the integration of mini INS with different external measuring devices like GPS navigation, which is considered as the most precise facilities of determination of moving object position, magnetic compass, and air data sensor (Kortunov, Dybska, Proskura, & Kravchuk, 2009)

References
Gupta, A. K., Arora, S. K., & Wescott, J. R. (2016). Industrial automation and robotics: An introduction., 390-401. Retrieved from https://ebookcentral-proquest-com.ezproxy.libproxy.db.erau.edu/lib/erau/reader.action?docID=4895078&query=industrial+automation+and+robotics%C2%A0(Links%20to%20an%20external%20site.)#
Kortunov, V. I., Dybska, I. Y., Proskura, G. A., & Kravchuk, A. S. (2009). Integrated mini INS based on MEMS sensors for UAV control. Retrieved from https://ieeexplore-ieee-org.ezproxy.libproxy.db.erau.edu/xpls/icp.jsp?arnumber=4772754
Mejias, L., Lai, J., & Bruggemann, T. (2015). Sensors for missions Springer, Dordrecht. Retrieved from https://search.credoreference.com/content/entry/sprunmanned/sensors_for_missions/0



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