17 resultados para Quadrotor. Variable reference control. Position and orientation control. UAV s
Resumo:
This paper explores the literary representation of Iceland and Norway in two short stories by contemporary German writer Judith Hermann. It analyses both the depiction of these countries as part of the globalised western world and the redemptive power they are tentatively ascribed by the author. Continuing a long German tradition of looking at Scandinavia from an almost colonial perspective, Hermann on the one hand presents these northern countries as a mere extension of central Europe, largely devoid of distinguishing national characteristics. At the same time she makes reference to the topos of the north as a vast and empty space and highlights both the specific arctic nature of the environment and the effect it has on her urban characters, who find themselves on a search for meaning and orientation in a postmodern fragmented world. Despite Hermann's overall sceptical attitude towards her characters' quest for happiness, these northern locations ultimately appear as potential places of self-realisation and enlightenment.
Resumo:
This research develops a low cost remote sensing system for use in agricultural applications. The important features of the system are that it monitors the near infrared and it incorporates position and attitude measuring equipment allowing for geo-rectified images to be produced without the use of ground control points. The equipment is designed to be hand held and hence requires no structural modification to the aircraft. The portable remote sensing system consists of an inertia measurement unit (IMU), which is accelerometer based, a low-cost GPS device and a small format false colour composite digital camera. The total cost of producing such a system is below GBP 3000, which is far cheaper than equivalent existing systems. The design of the portable remote sensing device has eliminated bore sight misalignment errors from the direct geo-referencing process. A new processing technique has been introduced for the data obtained from these low-cost devices, and it is found that using this technique the image can be matched (overlaid) onto Ordnance Survey Master Maps at an accuracy compatible with precision agriculture requirements. The direct geo-referencing has also been improved by introducing an algorithm capable of correcting oblique images directly. This algorithm alters the pixels value, hence it is advised that image analysis is performed before image georectification. The drawback of this research is that the low-cost GPS device experienced bad checksum errors, which resulted in missing data. The Wide Area Augmented System (WAAS) correction could not be employed because the satellites could not be locked onto whilst flying. The best GPS data were obtained from the Garmin eTrex (15 m kinematic and 2 m static) instruments which have a highsensitivity receiver with good lock on capability. The limitation of this GPS device is the inability to effectively receive the P-Code wavelength, which is needed to gain the best accuracy when undertaking differential GPS processing. Pairing the carrier phase L1 with the pseudorange C/A-Code received, in order to determine the image coordinates by the differential technique, is still under investigation. To improve the position accuracy, it is recommended that a GPS base station should be established near the survey area, instead of using a permanent GPS base station established by the Ordnance Survey.