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Analysis of Effective Parameters in Localization Accuracy of Positioning Systems

Sadeghi, Mohammad | 2021

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 54681 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Behnia, Fereidoon
  7. Abstract:
  8. Target localization using positioning systems has long been considered by researchers in various fields.One of the important issues in localizing a target is the accuracy of its determined position. There are several parameters in the accuracy of position estimation. In a comprehensive view, these parameters can be divided into three general factors,including the relative geometry of the transmitters/receivers with respect to the target, the accuracy of measurements, and the type of target position estimator.The first factor, i.e. the relative geometry between the target and the transmit/receive antennas, plays an important role in localization accuracy. In the first part of this thesis, the effect of this relative geometry on the accuracy of localization is evaluated and the best geometry to achieve the best accuracy is examined. To this end, first, a comprehensive analysis of the effect of antenna geometry on coherent and non-coherent MIMO radars is presented; then, considering operational constraints such as geographical and communication limitations, the optimal sensor geometry in several types of positioning systems, is determined.The second factor, the accuracy of the measurements, depends on parameters such as transmitted and received signal power, operating frequency, transmitted signals bandwidth, and observation time. One approach to increase accuracy and reduce measurement error is to improve these parameters depending on the type of measurements. Improving these parameters usually comes with some implementation costs. Another approach to reduce the measurement errors is filtering and utilizing noise reduction methods after completion of the measurement. Based on the second approach, in the second part of this thesis, a suitable noise reduction method based on the savitzky-golay filter is presented and, the optimal parameters of the filter are calculated.The third factor limiting localization accuracy is the accuracy of the estimators. In any positioning system, according to the system parameters and the relative geometry between the antennas and target, a minimum level of error can be achieved. This minimum error is determined based on the Cramer-Rao lower bound (CRLB). The objective of all estimators is to bring down their estimation errors as close as possible to this bound. In the third part of this thesis, two efficient estimators are proposed for two practical issues related to the field of satellite, including determining the satellite position and localizing maritime targets using satellites; in such a way that the error of these estimator achieves the Cramer-Rao lower bound
  9. Keywords:
  10. Target Localization ; Fisher Information Matrix ; Estimation Accuracy ; Optimal Sensor Placement ; Cramer-Rao Bound ; Positioning ; Satellite Attitude Control

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