Open Access Theses and Dissertations

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You searched for subject:(Spatial Interference Mitigation). Showing records 1 – 3 of 3 total matches.

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University of Oklahoma

1. Irazoqui, Robin. An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/319751 

Fully digital arrays offer significant advantages in terms of flexibility and performance, however they suffer from dynamic range issues when used in the presence of in-band interferers. Higher dynamic range components may be used, but are more costly and power-hungry, making the implementation of such technology impractical for large arrays. This paper presents a way to mitigate those interferers by creating a spatial notch at the RF front-end with an antenna agnostic circuit placed at the feeding network of the antenna. This circuit creates a steerable null in the embedded element pattern that mitigates interferers at a specified incoming angle. A full mathematical model and closed-form expressions of the behavior of the circuit are obtained and compared to simulated and measured results. Up to 20 dB null in the embedded element pattern of a 1x8 array is achieved with less than 1.5 dB of insertion loss. A steerable null using phase shifters is shown to prove real-time changes in the null placement. Phase shifters are substituted by tunable filters and enable a significant boost in the overall performance. To further validate the concept, a real case scenario is set up with a desired signal and an interferer that is initially saturating the receiver. The receiver successfully demodulates the signal after the null is placed in the direction of the interferer. The circuitry is then expanded to a planar array to fully optimize the interferer-free scanning volume. Advisors/Committee Members: Fulton, Caleb (advisor), Palmer, Robert (committee member), Goodman, Nathan (committee member), Sigmarsson, Hjalti (committee member), Remling, Christian (committee member).

Subjects/Keywords: Radar; Spatial Interference Mitigation; RF Spatial Filtering; Nulling the Embedded Element Pattern

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Irazoqui, R. (2019). An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/319751

Chicago Manual of Style (16th Edition):

Irazoqui, Robin. “An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed March 08, 2021. http://hdl.handle.net/11244/319751.

MLA Handbook (7th Edition):

Irazoqui, Robin. “An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays.” 2019. Web. 08 Mar 2021.

Vancouver:

Irazoqui R. An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/11244/319751.

Council of Science Editors:

Irazoqui R. An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/319751


Delft University of Technology

2. Boonstra, A.J. Radio Frequency Interference Mitigation in Radio Astronomy.

Degree: 2005, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad  ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad 

The next generation of radio telescopes is expected to be one to two orders of magnitude more sensitive than the current generation. Examples of such new telescopes are the Low Frequency Array (LOFAR), currently under construction in the Netherlands, and the Square Kilometer Array (SKA), currently in a concept study phase. Another trend is that technological advances in the fields of electronics and communications systems have led to a vast increase in radio communication applications and systems, and also to an increasing demand for radio spectrum. These two trends, more sensitive telescopes and a much denser spectrum use, imply that radio astronomy will become more vulnerable to interference from radio transmitters. Although protection criteria exist for radio astronomy, it becomes increasingly difficult to keep the radio astronomy frequency bands free from interference. In order to mitigate interference in radio astronomical data, filtering techniques can be used. In this thesis, modern array signal processing techniques have been applied to narrow-band multichannel interference detection and excision, and to narrow-band spatial interference filtering. By investigating the subspace structure of the telescope array output covariance matrices, new results were found, such as upper limits on interference residuals after excision and spatial filtering. The effect of bandwidth, extendedness of the interfering sources, and multipath effects on the detection and spatial filter effectiveness were studied as well. The advantage of a multichannel approach over a single telescope approach was demonstrated by using experimental data from the Westerbork Synthesis Radio Telescope (WSRT). As the performance of mitigation algorithms can be improved by calibration of the telescope gains and noise powers, calibration algorithms were developed. These algorithms were verified both for single and dual polarised arrays. Finally, a LOFAR interference mitigation strategy was developed. Advisors/Committee Members: van der Veen, A.J..

Subjects/Keywords: interference; interference mitigation; radio astronomy; array signal processing; calibration; spatial filtering; excision

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Boonstra, A. J. (2005). Radio Frequency Interference Mitigation in Radio Astronomy. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad

Chicago Manual of Style (16th Edition):

Boonstra, A J. “Radio Frequency Interference Mitigation in Radio Astronomy.” 2005. Doctoral Dissertation, Delft University of Technology. Accessed March 08, 2021. http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad.

MLA Handbook (7th Edition):

Boonstra, A J. “Radio Frequency Interference Mitigation in Radio Astronomy.” 2005. Web. 08 Mar 2021.

Vancouver:

Boonstra AJ. Radio Frequency Interference Mitigation in Radio Astronomy. [Internet] [Doctoral dissertation]. Delft University of Technology; 2005. [cited 2021 Mar 08]. Available from: http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad.

Council of Science Editors:

Boonstra AJ. Radio Frequency Interference Mitigation in Radio Astronomy. [Doctoral Dissertation]. Delft University of Technology; 2005. Available from: http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; urn:NBN:nl:ui:24-uuid:caa1942c-4180-4a17-88db-cec359490aad ; http://resolver.tudelft.nl/uuid:caa1942c-4180-4a17-88db-cec359490aad


Virginia Tech

3. Bharadwaj, Vivek. Ultra-Wideband for Communications: Spatial Characteristics and Interference Suppression.

Degree: MS, Electrical and Computer Engineering, 2005, Virginia Tech

URL: http://hdl.handle.net/10919/33183 

Ultra-Wideband Communication is increasingly being considered as an attractive solution for high data rate short range wireless and position location applications. Knowledge of the statistical nature of the channel is necessary to design wireless systems that provide optimum performance. This thesis investigates the spatial characteristics of the channel based on measurements conducted using UWB pulses in an indoor office environment. The statistics of the received signal energy illustrate the low spatial fading of UWB signals. The distribution of the Angle of arrival (AOA) of the multipath components is obtained using a two-dimensional deconvolution algorithm called the Sensor-CLEAN algorithm. A spatial channel model that incorporates the spatial and temporal features of the channel is developed based on the AOA statistics. The performance of the Sensor-CLEAN algorithm is evaluated briefly by application to known artificial channels. UWB systems co-exist with narrowband and other wideband systems. Even though they enjoy the advantage of processing gain (the ratio of bandwidth to data rate) the low energy per pulse may cause these narrow band interferers (NBI) to severely degrade the UWB system's performance. A technique to suppress NBI using multiple antennas is presented in this thesis which exploits the spatial fading characteristics. This method exploits the vast difference in fading characteristics between UWB signals and NBI by implementing a simple selection diversity scheme. It is shown that this simple scheme can provide strong benefits in performance. Advisors/Committee Members: Buehrer, R. Michael (committeechair), Bostian, Charles W. (committee member), Reed, Jeffrey Hugh (committee member).

Subjects/Keywords: Ultra-wideband; selection diversity; interference mitigation; spatial channel modeling; deconvolution; antenna array

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bharadwaj, V. (2005). Ultra-Wideband for Communications: Spatial Characteristics and Interference Suppression. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/33183

Chicago Manual of Style (16th Edition):

Bharadwaj, Vivek. “Ultra-Wideband for Communications: Spatial Characteristics and Interference Suppression.” 2005. Masters Thesis, Virginia Tech. Accessed March 08, 2021. http://hdl.handle.net/10919/33183.

MLA Handbook (7th Edition):

Bharadwaj, Vivek. “Ultra-Wideband for Communications: Spatial Characteristics and Interference Suppression.” 2005. Web. 08 Mar 2021.

Vancouver:

Bharadwaj V. Ultra-Wideband for Communications: Spatial Characteristics and Interference Suppression. [Internet] [Masters thesis]. Virginia Tech; 2005. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/10919/33183.

Council of Science Editors:

Bharadwaj V. Ultra-Wideband for Communications: Spatial Characteristics and Interference Suppression. [Masters Thesis]. Virginia Tech; 2005. Available from: http://hdl.handle.net/10919/33183

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