On Parameter Estimation : Applications in Radio Astronomy and Power Networks

Abstract: Signal processing is a common part of the modern society used to obtain high functionality in a vast number of applications. As the development of advanced electronics and powerful computers continue, the limit of the functionality in many systems is increased. Furthermore, as the signal processing can be performed on digitalized signals more advanced methods and algorithms can be employed and enhance the results. In radio-based astronomy a new window of discovery against space has opened using digitally based antenna array systems to observe signals with spectral contents ranging up to a major part of the VHF-band. This enables a high degree of flexibility and incorporates several areas e.g. radio astronomy, signal processing and advanced electronic design, in the development and construction of the technology. The usage of digital signal processing is also seen in power networks to control and monitor the state of the system. The power network is a complex and vital construction for the population that demand a high degree of security and reliability. Methods for monitoring and diagnostics are needed. If a fault can be found with high accuracy the time spent on repairs can be kept low reducing the cost and the consumers discontent. This thesis concerns parameter estimation within radio-based astronomy and fault localization on power lines. In this thesis the connection between the two areas is the use of electromagnetic modelling of underlying physical properties, parameter estimation and digitally based equipment used for advanced signal processing. The first area concerns the estimation of properties of electromagnetic waves e.g. direction of arrival and state of polarization, using an antenna array consisting of Tripole antennas. The properties of this antenna and the corresponding array configuration are investigated in part I-III of this thesis. The second area concerns fault localization on power lines using frequency modulated radar techniques. Part IV and V of this thesis present the concept and properties of this fault locator.