Tethered aerial vehicle for remote soil moisture sensing.

Efficiently managing soil moisture content on large farms can be a complicated and expensive task that if not done correctly, will have adverse affects on the health of crops. Soil moisture sensing can be achieved through terrestrial and airborne methods where the latter can achieve large coverage areas at a low cost. Two differ- ent Low Altitude Platforms (LAPs) are proposed where their main goal is to ensure the soil moisture sensing system can be reliably retained at some altitude Above Ground Level (AGL). A Tethered Balloon System (TBS) was developed to provide a simple and low cost platform that could be deployed in remote locations. This thesis develops a minimal model for a tethered spherical balloon where the focus is towards the effect of wind speed on the balloons altitude. Experimental testing of this system showed that it successfully operated for time periods up to 48 hours and had potential for operating over much longer time periods. A LAP using a Unmanned Aerial Vehicle (UAV) is proposed to enable longer flight times than that of the TBS. The research is focused towards developing a Power over Tether (PoT) system that power the platform from the ground. The PoT system was experimentally tested with multi-rotor UAV where it was found to successfully maintain hovered flight for time periods up to 30 minutes. A remote soil moisture sensing system was developed to identify locations of bare or dead grass patches on a farm. The system uses a standard camera and multi- spectral camera to compare the advantages of both imaging methods. The standard camera produced reliable results and contained several features that overcame some major limitations seen with multispectral cameras. Thus, a standard camera is bet- ter suited to this soil moisture sensing application. A georeferencing algorithm was developed to provide the physical location for any point within the image and with an error of approximately 2 m