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Title: Development of a power based angle of arrival system for tracking of bee utlilising a miniature vibration energy harvester for a battery-less transmitter
Author: Shearwood, Jake
ISNI:       0000 0004 9358 6222
Awarding Body: Bangor University
Current Institution: Bangor University
Date of Award: 2020
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The thesis presents the adaption of radio telemetry technology to allow for the tracking of the world’s most economically beneficial insect, the honeybee. Currently no technology is available to efficiently enable the long-term evaluation of navigation loss of bees exposed to potentially harmful pesticides such as neonicotinoids. The research aims at developing a self-sustained radio tracking device which can be attached to insects as small as the honeybee. The research presented within the thesis acts as a proof of principle for long range autonomous tracking of bees using a modified radio telemetry. To allow for compatibility of radio telemetry tags with smaller tags were designed and fabricated which implements a micro-generator that harvests electrical energy from the bee’s body vibrations which powers radio-wave transmission from a miniaturized antenna attached to the bees’ thorax. The use of lead zirconate titanate (PZT) allowed for sufficient power generation to replace the battery, whilst an increased operation frequency in comparison to current state of the art allowed for sufficient antenna size reduction. Both factors contributed to a significant weight reduction allowing for compatibility with honeybees. The successful transmission of the selfpowered radio telemetry tags is shown whilst outlining the effects of the battery replacement and increased frequency on the link budget of the system. A review of localisation systems for radio telemetry systems was performed in which alternative methods were investigated to allow for autonomous localisation of the radio telemetry tag with a single receiver. A compact phased array antenna affords angle of arrival (AOA) estimation and bee localisation through a received signal strength indicator approach (RSSI). The phased array antenna is capable of scanning +/-50° in azimuth and elevation. Additionally, a reflection type phase shifter capable of a 360° phase shift was designed and fabricated. Initial tests of the system were conducted in controlled environments and highlighted the system’s ability to detect and determine the AoA of a tagged bee within a 20m range. Further tests demonstrated the systems unobtrusive nature when monitoring the foraging times of tagged bees whilst recording their initial flight trajectories. Commercial applications of the system are shown in which the system is mounted within a polytunnel to monitor plant visitations and pollinator services on strawberry plants. To overcome the 20m detection range and achieve long range tracking of tagged bees the receiver unit was integrated to a drone in which the AOA estimate is autonomously fed into the control system of a drone, allowing for continuous position updates. The drone interprets the estimate in which a bearing is calculated before the drone autonomously moves towards the position of the AoA estimate. The experimental results show proof of concept towards autonomous tracking of tagged bees.
Supervisor: Cross, Paul ; Palego, Cristiano Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Energy harvesting ; Localisation ; Phased arrays ; RSSI ; Telemetry