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Dissertations / Theses on the topic 'Antenna processing'
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1
Sabbar, Bayan M. "High resolution array signal processing." Thesis, Loughborough University, 1987. https://dspace.lboro.ac.uk/2134/27193.
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This study is concerned with the processing of signals received by an array of sensor elements which may range from acoustic transducers in a sonar system to microwave horns in a radar system. The main aim of the work is to devise techniques for resolving the signals arriving from closely spaced sources in order to determine the presence and direction of these sources.
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Wennerholm, Lucas, and Adam Alenius. "Antenna Characterization with Autonomous UAV and Software Defined Radio." Thesis, Uppsala universitet, Signaler och System, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-355444.
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A measurement equipment with the purpose of measuring the radiation pattern of antennas in the frequency interval 30-300 MHz was constructed. To perform the necessary measurements the equipment needs to be mounted on a UAV, a necessity that demands a low weight from the measurement equipment. These kinds of measurements are today done with equipment that is mounted on helicopters, making the equipment smaller and fitting it on an UAV will save cost for the persons or companies that need to utilize this service. To ensure that the system is easy to use for anyone who wants to characterize an antenna efforts were made to make the software application user friendly. The system visualizes measurement results in 2D diagrams that are simple to analyze. Since the equipment has size restrictions the computer in the system needs to be small and light. The single board computer used has computational limitations and therefore the digital signal processing must be carefully designed to both be fast and generate good measurement data. To verify the performance of the system tests and theoretical simulations where performed and compared. The tests were performed both in an echo free antenna chamber and in realistic outdoor environments with an UAV. The finished system performed well and the measurement results showed clear similarities with the theoretical simulations. The outdoor environment clearly influences the shape of an antennas radiation pattern and the need to characterize antennas in a realistic environment became clear.
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Shapoury, Alireza. "Ultra wideband antenna array processing under spatial aliasing." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1495.
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Bengtsson, Mats. "Antenna array signal processing for high rank data models." Doctoral thesis, KTH, Signaler, sensorer och system, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2903.
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Chakravorti, Mark F. J. "CMOS analog signal processing for a smart antenna system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/MQ49671.pdf.
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Kaiser, Julius A. "RETRODIRECTIVE ANTENNA SYSTEM." International Foundation for Telemetering, 1995. http://hdl.handle.net/10150/608421.
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International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada<br>Two retrodirective antenna systems that autonomously point high gain beams to a
signal source without requiring a priori knowledge of location are described. The first
is a stationary phased array requiring no phase shifters or switches for its operation.
The second is a steerable platform with a thinned receive array for signal acquisition
and platform pointing and dish(es) to satisfy the high gain function.
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Kogon, Stephen Michel. "Adaptive array processing tecniques for terrain scattered interference mitigation." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/14927.
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Alam, Fakhrul. "Space Time Processing for Third Generation CDMA Systems." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/29669.
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The capacity of a cellular system is limited by two different phenomena, namely multipath fading and multiple access interference (MAI). A Two Dimensional (2-D) receiver combats both of these by processing the signal both in the spatial and temporal domain. An ideal 2-D receiver would perform joint space-time processing, but at the price of high computational complexity. In this dissertation we investigate computationally simpler technique termed as a Beamformer-Rake. In a Beamformer-Rake, the output of a beamformer is fed into a succeeding temporal processor to take advantage of both the beamformer and Rake receiver. Wireless service providers throughout the world are working to introduce the third generation (3G) cellular service that will provide higher data rates and better spectral efficiency. Wideband CDMA (WCDMA) has been widely accepted as one of the air interfaces for 3G. A Beamformer-Rake receiver can be an effective solution to provide the receivers enhanced capabilities needed to achieve the required performance of a WCDMA system. This dissertation investigates different Beamformer-Rake receiver structures suitable for the WCDMA system and compares their performance under different operating conditions. This work develops Beamformer-Rake receivers for WCDMA uplink that employ Eigen-Beamforming techniques based on the Maximum Signal to Noise Ratio (MSNR) and Maximum Signal to Interference and Noise Ratio (MSINR) criteria. Both the structures employ Maximal Ratio Combining (MRC) to exploit temporal diversity.
MSNR based Eigen-Beamforming leads to a Simple Eigenvalue problem (SE). This work investigates several algorithms that can be employed to solve the SE and compare the algorithms in terms of their computational complexity and their performance. MSINR based Eigen-Beamforming results in a Generalized Eigenvalue problem (GE). The dissertation describes several techniques to form the GE and algorithms to solve it. We propose a new low-complexity algorithm, termed as the Adaptive Matrix Inversion (AMI), to solve the GE. We compare the performance of the AMI to other existing algorithms. Comparison between different techniques to form the GE is also compared. The MSINR based beamforming is demonstrated to be superior to the MSNR based beamforming in the presence of strong interference.
There are Pilot Symbol Assisted (PSA) beamforming techniques that exploit the Minimum Mean Squared Error (MMSE) criterion. We compare the MSINR based Beamformer-Rake with the same that utilizes Direct Matrix Inversion (DMI) to perform MMSE based beamforming in terms of Bit Error Rate (BER). In a wireless system where the number of co-channel interferers is larger than the number of elements of a practical antenna array, we can not perform explicit null-steering. As a result the advantage of beamforming is partially lost. In this scenario it is better to attain diversity gain at the cost of spatial aliasing. We demonstrate this with the aid of simulation.
Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier technique that has recently received considerable attention for high speed wireless communication. OFDM has been accepted as the standard for Digital Audio Broadcast (DAB) and Digital Video Broadcast (DVB) in Europe. It has also been established as one of the modulation formats for the IEEE 802.11a wireless LAN standard. OFDM has emerged as one of the primary candidates for the Fourth Generation (4G) wireless communication systems and high speed ad hoc wireless networks. We propose a simple pilot symbol assisted frequency domain beamforming technique for OFDM receiver and demonstrate the concept of sub-band beamforming. Vector channel models measured with the MPRG Viper test-bed is also employed to investigate the performance of the beamforming scheme.<br>Ph. D.
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Wang, Xudong. "Microwave Photonic Signal Processing." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10087.
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A new single-wavelength coherence-free microwave photonic notch filter is presented. The concept is based on a dual Sagnac loop structure that functions with a new principle in which the two loops operate with different free spectral ranges. Experimental results demonstrate a notch filter with a narrow notch width, a flat passband, and high stopband attenuation of over 40 dB. A new multiple-tap microwave photonic notch filter structure that can simultaneously realise a frequency-independent group delay together with a narrow notch filter response and large free spectral range is presented. The concept is based on using multiple wavelengths circulating in a Sagnac loop. Experimental results demonstrate a notch filter with a flat passband, a narrow notch width, a high rejection level of over 40 dB, and an extremely low group delay ripple of less than ±25 ps. A new photonic microwave phase shifting structure that can realise a continuous 0o to 360o phase shift with only little frequency dependent amplitude and phase variation over a wide frequency range is presented. It is based on controlling the wavelengths of two phase modulated optical signals into an optical filter with a nonlinear phase response. The new photonic microwave phase shifter has been experimentally verified showing the continuous 0o to 360o phase shifting operation with less than 3 dB amplitude variation over a wide frequency range. A new microwave photonic phase shifter structure is presented. It is based on the conversion of the optical carrier phase shift into an RF signal phase shift via controlling the carrier wavelength of a single-sideband RF modulated optical signal into a fibre Bragg grating. Experimental results demonstrate a continuous 0o to 360o phase shift with low amplitude variation of < 2 dB and low phase deviation of < 5o over a wideband microwave range.
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Hicks, James Edward. "Novel Approaches to Overloaded Array Processing." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/28670.
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An antenna array is overloaded when the number of cochannel signals in its operating environment exceeds the number of elements. Conventional space-time array processing for narrow-band signals fails in overloaded environments. Overloaded array processing (OLAP) is most difficult when signals impinging on the array are near equal power, have tight excess bandwidth, and are of identical signal type. Despite the failure of conventional beamforming in such environments, OLAP becomes possible when a receiver exploits additional signal properties such as the finite-alphabet property and signal excess-bandwidth. This thesis proposes three approaches to signal extraction in overloaded environments, each providing a different tradeoff in performance and complexity. The first receiver architecture extracts signals from an overloaded environment through the use of MMSE interference rejection filtering embedded in a successive interference cancellation (SIC) architecture. The second receiver architecture enhances signal extraction performance by embedding a stronger interference rejection receiver, the reduced-state maximum aposteriori probability (RS-MAP) algorithm in a similar SIC architecture. The third receiver fine-tunes the performance of spatially reduced search joint detection (SRSJD) with the application of an energy focusing transform (EFT), a complexity reducing front-end linear pre-processor. A new type of EFT, the Energy Focusing Unitary Relaxed Transform (EFURT) is developed. This transform facilitates a continuous tradeoff between noise-enhancement and error-propagation in an SRSJD framework. EFURT is used to study the role of this tradeoff for SRSJD receivers in a variety of signal environments. It is found that for the environments studied in this thesis, SRSJD enjoys an aggressive reduction in interference at the expense of possible noise-enhancement.<br>Ph. D.
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Jusoh, Tajudin Mohd Taufik. "Study and design of reconfigurable antennas using plasma medium." Phd thesis, Université Rennes 1, 2014. http://tel.archives-ouvertes.fr/tel-01060295.
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Plasma is the 4th state of matter with complex permittivity that can be exploited to give advantages in communication system. Its negative permittivity has been studied in many research papers and it was proven to have similar characteristics as metal material in terms of electrical conductivity. While keeping permeability in the positive region, plasma will respond to electromagnetic waves in the similar manner as metal. Therefore, this thesis aimed to use plasma as an alternative to metal in the construction of reconfigurable antennas. The first part of this thesis is dedicated to characterize a plasma model based on the commercially available plasma source. Since there are many type of plasma source in terms of their electrical properties and physical shapes, it is important to characterize a particular plasma source so that it can be modeled in simulations to construct other types of plasma antennas. The second part presents the realization of plasma reflector antennas. Two types of plasma reflector antennas have been simulated, fabricated and measured at 2.4 GHz. The first one is are round reflector antenna (RRA) and the second one is corner reflector antenna (CRA). The performances of RRA have been validated and it was proven to provide beam shaping and beam scanning capability. The measured radiation patterns are in a good agreement with simulation ones. The capability of RRA is exceptional since it can steer its main beam from 0° up to 360°. Moreover, the scanning gain remains the same as the main beam is being moved from one direction to another. The CRA that has been introduced in this thesis is a novel design since it integrates two corner-reflector antennas on a single ground plane. The CRA offers three beam shapes which are electrically switchable from one shape to another. The CRA was simulated, fabricated and finally its performances were validated throughout a series of agile measurements. The measured reflected radiation patterns are in good agreements with the simulation ones. The measured gains of the RRA and CRA are 5 dB higher than the gain of classical monopole antenna with an identical size of finite ground plane. The fourth part deals with plasma as radio waves radiator. Two plasma antennas using commercially available U-shaped compact fluorescent lamp (CFL) have been fabricated and measured and it was proven that these antennas can be to radiate radio signal. The last part discusses about radar cross section performance of the plasma reflector antennas. The two plasma reflector antennas (RRA and CRA) were tested and measured for their RCS performance.
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Glenn, Dickins, and glenn dickins@dolby com. "Applications of Continuous Spatial Models in Multiple Antenna Signal Processing." The Australian National University. Research School of Information Sciences and Engineering, 2008. http://thesis.anu.edu.au./public/adt-ANU20080702.222814.
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This thesis covers the investigation and application of continuous spatial models for multiple antenna signal processing. The use of antenna arrays for advanced sensing and communications systems has been facilitated by the rapid increase in the capabilities of digital signal processing systems. The wireless communications channel will vary across space as different signal paths from the same source combine and interfere. This creates a level of spatial diversity that can be exploited to improve the robustness and overall capacity of the wireless channel. Conventional approaches to using spatial diversity have centered on smart, adaptive antennas and spatial beam forming. Recently, the more general theory of multiple input, multiple output (MIMO) systems has been developed to utilise the independent spatial communication modes offered in a scattering environment.¶
Underlying any multiple antenna system is the basic physics of electromagnetic wave propagation. Whilst a MIMO system may present a set of discrete inputs and outputs, each antenna element must interact with the underlying continuous spatial field. Since an electromagnetic disturbance will propagate through space, the field at different positions in the space will be interrelated. In this way, each position in the field cannot assume an arbitrary independent value and the nature of wave propagation places a constraint on the allowable complexity of a wave-field over space. To take advantage of this underlying physical constraint, it is necessary to have a model that incorporates the continuous nature of the spatial wave-field. ¶This thesis investigates continuous spatial models for the wave-field. The wave equation constraint is introduced by considering a natural basis expansion for the space of physically valid wave-fields. This approach demonstrates that a wave-field over a finite spatial region has an effective finite dimensionality. The optimal basis for representing such a field is dependent on the shape of the region of interest and the angular power distribution of the incident field. By applying the continuous spatial model to the problem of direction of arrival estimation, it is shown that the spatial region occupied by the receiver places a fundamental limit on the number and accuracy with which sources can be resolved. Continuous spatial models also provide a parsimonious representation for modelling the spatial communications channel independent of specific antenna array configurations. The continuous spatial model is also applied to consider limits to the problem of wireless source direction and range localisation.
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Predoehl, Andrew M. "Time domain antenna pattern measurements." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-11072008-063651/.
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LIU, HUAZHOU. "DIGITAL DIRECTION FINDING SYSTEM DESIGN AND ANALYSIS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060976413.
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Sayyah, Jahromi Mohammad Reza Information Technology & Electrical Engineering Australian Defence Force Academy UNSW. "Efficient broadband antenna array processing using the discrete fourier form transform." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Information Technology and Electrical Engineering, 2005. http://handle.unsw.edu.au/1959.4/38690.
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Processing of broadband signals induced on an antenna array using a tapped delay line filter and a set of steering delays has two problems. Firstly one needs to manipulate large matrices to estimate the filter coefficients. Secondly the use of steering delays is not only cumbersome but implementation errors cause loss of system performance. This thesis looks at both of these problems and presents elegant solutions by developing and studying a design method referred to as the DFT method, which does not require steering delays and is computationally less demanding compared to existing methods. Specifically the thesis studies and compares the performance of a time domain element space beamformer using the proposed method and that using an existing method, and develops the DFT method when the processor is implemented in partitioned form. The study presented in the thesis shows that the processors using the DFT method are robust to look direction errors and require less computation than that using the existing method for comparable performance. The thesis further introduces a broadband beamformer design which does not require any steering delays between the sensors and the tapped delay line section as is presently the case. It has the capability of steering the array in an arbitrary direction with a specified frequency response in the look direction while canceling unwanted uncorrelated interferences. The thesis presents and compares the performance of a number of techniques to synthesize an antenna pattern of a broadband array. These techniques are designed to produce isolated point nulls as well as broad sector nulls and to eliminate the need for the steering delays. Two of the pattern synthesis techniques presented in the thesis allow optimization against unwanted interferences in unknown directions. The techniques allow formulation of a beamforming problem such that the processor is not only able to place nulls in specified directions but also able to cancel directional interferences in unknown directions along with a specified frequency response in the look direction over a band of interest. The thesis also presents a set of directional constraints such that one does not need steering delays and an array can be constrained in an arbitrary direction with a specified frequency response. The constraints presented in the thesis are simple to implement. Based on these constraints a pattern synthesis technique for broadband antenna array is also presented.
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Astély, David. "Spatial and spatio-temporal processing with antenna arrays in wireless systems /." Stockholm, 1999. http://www.lib.kth.se/abs99/aste0601.pdf.
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Jackson, Ronald Edward Ramadoss Ramesh. "MEMS based tunable microstrip patch antenna fabricated using printed circuit processing techniques." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/JACKSON_RONALD_51.pdf.
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Abewardana, Wijenayake Chamith K. "Multi-dimensional Signal Processing And Circuits For Advanced Electronically Scanned Antenna Arrays." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1415358304.
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Bangsgaard, Christian, Tobias Erlandsson, and Alexander Örning. "EXTREME PROCESSORS FOR EXTREME PROCESSING : STUDY OF MODERATELY PARALLEL PROCESSORS." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-194.
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<p>Future radars require more flexible and faster radar signal processing chain than commercial radars of today. This means that the demands on the processors in a radar signal system, and the desire to be able to compute larger amount of data in lesser time, is constantly increasing. This thesis focuses on commercial micro-processors of today that can be used for Active Electronically Scanned Array Antenna (AESA) based radar, their physical size, power consumption and performance must to be taken into consideration. The evaluation is based on theoretical comparisons among some of the latest processors provided by PACT, PicoChip, Intrinsity, Clearspeed and IBM. The project also includes a benchmark made on PowerPC G5 from IBM, which shows the calculation time for different Fast Fourier Transforms (FFTs). The benchmark on the PowerPC G5 shows that it is up to 5 times faster than its predecessor PowerPC G4 when it comes to calculate FFTs, but it only consumes twice the power. This is due to the fact that PowerPC G5 has a double word length and almost twice the frequency. Even if this seems as a good result, all the PowerPC´s that are needed to reach the performance for an AESA radar chain would consume too much power. The thesis ends up with a discussion about the traditional architectures and the new multi-core architectures. The future belongs with almost certainty to some kind of multicore processor concept, because of its higher performance per watt. But the traditional single core processor is probably the best choice for more moderate-performance systems of today, if you as developer looking for a traditional way of programing processors.</p>
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Schodorf, Jeffrey Brian. "Array processing techniques for interference suppression in mobile communications systems." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/12971.
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Yildirim, Gokhan. "Antenna Patterns For Detecting Slowly Moving Targets In Two Channel Gmti Processing." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12612152/index.pdf.
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Ground Moving Target Indicator (GMTI) is a well-known and widely used signal processing method in airborne and spaceborne radars. In airborne radar and GMTI literature, many radar designs and signal processing techniques have been developed to increase the detection and estimation performance under heavy interference conditions. The motion of the aircraft on which the radar is mounted, high altitudes and ranges, targets with low radar cross sections and slowly moving targets complicates the problem of localization and observation of moving targets on a huge area of interest. In order to overcome these problems, engineers developed more complex radar hardwares with many receiver channels and signal processing algorithms. Multi-channel receivers provide adaptive digital beam-forming and adaptive Doppler processing capabilities. However, designing a cost efficient and light multi-channel receiver and a signal processing unit, which can handle a huge amount of received data from multi channels, is a difficult task to accomplish. Therefore, this thesis aims to propose non-adaptive antenna beams to reduce the number of channels to two in GMTI processing. This reduction yields a simplification both in receiver structure and signal processing unit. The measure of excellence of these propositions will be the ability to detect slowly moving targets with nearly optimum performance.
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Jahan, Adil Shah. "Improved antenna array processing and service enhancements for 3G systems and beyond." Thesis, King's College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440466.
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Hicks, James. "Overloaded Array Processing with Spatially Reduced Search Joint Detection." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/9611.
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An antenna array is overloaded when the number of cochannel signals in its operating environment exceeds the number of elements. Conventional space-time array processing for narrow-band signals fails in overloaded environments. Overloaded array processing (OAP) is most difficult when signals impinging on the array are near equal power, have tight excess bandwidth, and are of identical signal type. In this thesis, we first demonstrate how OAP is theoretically possible with the joint maximum likelihood (JML) receiver. However, for even a modest number of interfering signals, the JML receiverà Âs computational complexity quickly exceeds the real-time ability of any computer. This thesis proposes an iterative joint detection technique, Spatially Reduced Search Joint Detection, (SRSJD), which approximates the JML receiver while reducing its computational complexity by several orders of magnitude. This complexity reduction is achieved by first exploiting spatial separation between interfering signals with a linear pre-processing stage, and second, performing iterative joint detection with a (possibly) tail-biting and time"-varying trellis. The algorithm is sub-optimal but is demonstrated to well approximate the optimum receiver in modest signal to interference ratios. SRSJD is shown to demodulate over 2M zero excess bandwidth synchronous QPSK signals with an M element array. Also, this thesis investigates a temporal processing technique similar to SRSJD, Temporally Reduced Search Joint Detection (TRSJD), that separates co-channel, asynchronous, partial response signals. The technique is demonstrated to separate two near equal power QPSK signals with r= .35 root raised-cosine pulse shapes."<br>Master of Science
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Wortham, Cody. "Space-Time Processing for Ground Surveillance Radar." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14468.
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As the size of an adaptive antenna array grows, the system is able to resist interference signals of increasing bandwidth. This is a result of the transmit pattern gain increasing, which raises the target's return power, and a greater number of degrees of freedom. However, once the interference signal decorrelates completely from one channel to the next, increasing array size will cease to improve detection capability. The use of tapped delay-line processing to improve correlation between channels has been studied for smaller arrays with single element antennas, but previous analyses have not considereded larger systems that are partitioned into subarrays.
This thesis quantifies the effect that subarrays have on performance, as measured by the interference bandwidth that can be handled, and explains how tapped delay-line processing can maintain the ability to detect targets in an environment with high bandwidth interference. The analysis begins by deriving equations to estimate the half-power bandwidth of an array with no taps. Then we find that a single delay with optimal spacing is sufficient to completely restore performance if the interference angle is known exactly. However, in practice, the tap spacing will never be optimal because this angle will not be known exactly, so further consideration is given to this non-ideal case and possible solutions for arbitrary interference scenarios are presented. Simulations indicate that systems with multiple taps have more tolerance to increasing interference bandwidth and unknown directions of arrival. Finally, the tradeoffs between ideal and practical configurations are explained and suggestions are given for the design of real-world systems.
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Ponnekanti, S. "Efficient antenna based interference cancellation systems for narrowband and broadband signals." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282764.
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Koike, Toshiaki. "Space-time-frequency signal processing for spectrum-efficient multiple-antenna wireless transmission systems." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144509.
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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(情報学)<br>甲第11908号<br>情博第180号<br>新制||情||40(附属図書館)<br>23688<br>UT51-2005-N742<br>京都大学大学院情報学研究科通信情報システム専攻<br>(主査)教授 吉田 進, 教授 酒井 英昭, 教授 佐藤 亨<br>学位規則第4条第1項該当
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Tung, Tai-Lai, Kung Yao, and Don Whiteman. "MULTIPLE-ANTENNA SPATIO-TEMPORAL PROCESSING FOR OFDM COMMUNICATIONS OVER FREQUENCY-SELECTIVE FADING CHANNELS." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606486.
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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California<br>In this paper, we propose applying the spatio-temporal signal processing and OFDM techniques to
a multiple-antenna system in order to achieve high data rate and high performance transmission
capability. In order to perform real time processing for this system, we also propose a complexity
reduced QR beamforming algorithm. The performance of the proposed system has been investigated
for a two-ray frequency-selective fading model by extensive computer simulations. These results
show that significant benefits can be realized in terms of lower bit error rate and higher data
transmission rate.
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Rundquist, Victor Frederic. "Weak signal reception using software defined radios and a two-element antenna array." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/RUNDQUIST_VICTOR_6.pdf.
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Mackenzie, Donald, and Richard Fielding. "Control of a Remote Receiving Station and Data Processing at RA Range Hebrides." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/611665.
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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California<br>The Royal Artillery Range (RA Range) is the British Army's weapons practice range in the Outer Hebrides of Scotland. The large sea range is also used by the Royal Air Force and Royal Navy for new weapons system evaluation and in service practice firing. This paper describes the telemetry facility comprising of two prime sites separated by 40 miles of open sea. Tracking antennas and receivers are at the remote island site of St Kilda with data processing and control at the Range Control Base (RCB), Benbecula. To improve operational capabilities and effectiveness, full remote control and monitoring of the multiple receivers and combiners has been installed. Radar tracking outputs are processed in the telemetry computer to produce individual antenna pointing demands.
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Bayram, Saffet. "Overloaded Array Processing: System Analysis, Signal Extraction Techniques, and Time-delay Estimation." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/36039.
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In airborne communication systems such as airborne cell-extender repeaters the receiver faces the challenge of demodulating the signal of interest (SOI) in the presence of excessive amounts of Co-Channel Interference (CCI) from a large number of sources. This results in the overloaded environment where the number of near-equal power co-channel interferers exceeds the number of antenna array elements. This thesis first analyzes the interference environment experienced by an airborne cellular repeater flying at high altitudes. Link budget analysis using a two-ray propagation model shows that the antenna array mounted on an airborne receiver has to recover the SOI out of hundreds of co-channel interfering signals. This necessitates use of complex overloaded array signal processing techniques. An extensive literature survey on narrowband signal extraction algorithms shows that joint detection schemes, coupled with antenna arrays, provide a solution for narrowband overloaded array problem where as traditional beamforming techniques fail. Simulation results in this thesis investigates three "promising" overloaded array processing algorithms, Multi-User Decision Feedback Equalizer (MU-DFE), Iterative Least Squares with Projection (ILSP), and Iterative Least Squares with Enumeration (ILSE). ILSE is a non-linear joint maximum-likelihood detector, is shown to demodulate many more signals than elements even when the users are closely spaced and the channel is blindly estimated.
Multi-user time delay estimation is one of the most important aspects of channel estimation for overloaded array processing. The final chapter of the thesis proposes a low-complexity data-aided time-delay estimation structure for embedding in a Per Survivor Processing (PSP) trellis for overloaded array processing. An extensive analysis proves that the multi-user delay estimation is separable, which leads to the proposed multi-user algorithm that estimates the user delays with a bank of simple data-aided synchronization loops to reduce the complexity. This thesis shows simulation results for the single-user case where the low-complexity Delay Locked Loop (DLL) structure, working at a low oversampling rate of 2 samples per symbol, estimates and compensates for any integer or non-integer sample delay within ±Tsym(symbol period).
Two extensions to this technique are proposed to provide efficient multi-user delay estimation. The first multi-user structure employs a bank of DLLs, which compensate for the timing offset of each user simultaneously. This multi-user algorithm is suitable for CDMA-type applications, where each user has a distinct PN-code with good auto- and cross-correlation properties. We show that for spreading gain of 31, the presence of an interpolator enables us to reduce the oversampling factor from 4 to 2 samples per chip. Thus, the requirements of the A/D converter are relaxed without sacrificing system performance. Furthermore, we show that the proposed scheme meets the requirements of multi-user interference cancellation techniques for residual worst-case timing errors, i.e., residual timing error < 0.2 Tc, as reported in [200]. Finally, the thesis recommends a similar multi-user structure for narrowband TDMA-type system, which is based on bank of DLLs with whitening pre-filters at the front end of each branch.<br>Master of Science
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Hyberg, Per. "Antenna array mapping for DOA estimation in radio signal reconnaissance." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-130.
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Bae, Kyung Kyoon. "Analytical Framework for the Performance Analysis of Multiple Antenna Systems." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29212.
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There has been great interest in antenna array processing (diversity, beamforming, null steering, and spatial multiplexing) to enhance the received signal quality and the capacity of
wireless communications systems. However, in order to properly exploit the characteristics of different array processing techniques, understanding trade-offs among different techniques and parametric investigation, which offers an insight as to what parameters determine system performance under different situations
is necessary. In this study, we present analytical framework which can facilitate the performance analysis of systems with antenna
array.
Five original contributions to the performance analysis of antenna array processing are presented in this study. First, we present theoretical outage probability of a system equipped with an array which suppresses a few dominant interering signals in TDMA cellular networks when the fading statistics of interfering
signals are independent but non-identically distributed. Most of the related previous works assumed either independent and identically distributed fading statistics among cochannel
interferences (CCI) or Rayleigh fading when CCI signals are subject to i.n.d. fading statistics. Secondly, the performance of multi-branch predetection equal gain combiner for different
modulation techniques in equally correlated Nakagami-$m$ fading is presented through analytical analysis. Specifically, the
characteristic function (CHF) and the moment generating function (MGF) of EGC output with correlated inputs are derived and used to evaluate the average symbol error probability (ASEP) and the outage probability performance, respectively. Thirdly, we derived analytical expression which can be used to analyze the
performance of different types of diversity techniques in equally correlated Nakagami-m or Rice fading channels. Fourthly, asymptotic analysis on different types of diversity combiners in generalized fading channels is presented in a unifying way. Finally, we investigate and present the impact of transmit
diversity at handsets on the reverse link DS/CDMA systems in terms of capacity and coverage over generalized fading channels through analytical approaches. Then, we validate the analytical results with simulation results and investigate practical issues which are hard to capture through analytical analysis using system level
simulator we developed.
Although we have mainly focused on applying the analytical framework we have derived in this work to the performance analysis of physical layer algorithms such as spatial diversity and
adaptive null steering, the framework can be extended to assist the analysis and design of wireless communication systems such as,
to name a few, distributed multiple input multiple output (MIMO) system in cooperative wireless networks, multipath routing protocol analysis in wireless fading channels, and antenna
selection problems in MIMO system.<br>Ph. D.
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Sakarya, Fatma Ayhan. "Passive source location estimation." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/13714.
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Salam, Naser. "Signal processing for multiple receive antenna systems in the presence of multiple access interference." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26761.
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In wireless communications systems employing DS-CDMA, the base stations with multiple antennas receive signals from different mobiles that are affected by fading and noise as well as interference from other users, thus diminishing the capacity. This dissertation considers a base station with multiple receive antennas which are weighted spatially by using maximal ratio combining. Moreover, at the transmitter side, the thesis examines the use of pilot signals along with the data stream for channel estimation purpose. For each user, the pilot signals are transmitted in parallel with the data signal using orthogonal signature waveforms to those of the data signal. The proposed receiver in this thesis uses a decorrelator detector to not only to decorrelate the data signal from the MAI components, but also to decorrelate the pilot signal to achieve good channel gain estimation. The study shows that the proposed system has a good resistance toward the near-far problem, give good space receiver performance efficiency comparing it with conventional space receivers and it has Less power assigned to the pilot power stream to obtain best channel estimation within a certain fading rate.
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Choudhary, Vipin. "Nondestructive testing and antenna measurements using UWB radar in industrial applications." Licentiate thesis, KTH, Teknisk informationsvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291129.
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Many industries are rapidly substituting the manual test operations and move towards automated operations using modern technologies.Modern technologies such as digital cameras, sonic sensors, infrared sensors, and radar and lidar systems are used for non-destructive testingoperations. Among all the different sensors, radar systems have theability to penetrate built structures (dielectric materials), which makes them flexible and suitable for a wide range of industrial and military applications in non-destructive sensing. Such examples are the detection of damages in goods manufacturing, monitoring the health of manystructures, object detection through the wall for security purposes, etc.In particular, ultra-wide-band (UWB) radar systems are beneficial inproviding high measurement accuracy and simultaneously reduced sensitivityto passive interference (such as rain, smoke, mist etc.), immunity to external radiation and noise.The objectives of this thesis are: I) to investigate electrically small concealed structures using synthetic aperture radar (SAR), II) to determinethe complex refractive index of objects using an UWB radar system,and III) to answer to the question how we can reduce the mutual coupling (cross talk) in an UWB radar system with collocated transmitand receive antennae. In objective I, the aim is non-destructive testing of built structures, such as in concrete slab manufacturing or for use in the renovation process. In addition electrically small periodic meshes,and their orientation, could not be distinguished in conventional SAR images. The proposed polarimetric analysis method demonstrates the usefulness of the singular value decomposition (SVD) using back projection algorithm (BPA) in extracting information about shape and for classifying an electrically small object. Further in this thesis for objective II, a new method for determining the complex refractive index (or equivalently the complex relative permittivity) of objects with planar interfaces is presented. The proposed method is relatively insensitive to hardware-impairments such as frequency-dependence of antennas and analog front end. The objects can be finite in size and at a finite distance. The limits in size and distance for the method to be valid are experimentally investigated. Hence, the method is designed for industrial in-line measurements onobjects on conveyor belts. Furthermore, in the following parts of this thesis −objective III− we investigate and show how a microwave metamaterial based absorber can be used to improve the performance of aradar system for short range applications, when positioned between the transmit and receive antennas. As results, the error in estimated target distance is reduced and clutter reduction is improved.<br>Många branscher ersätter snabbt de manuella testoperationerna och går mot automatiserad drift med modern teknik. Modern teknik såsom digitalkameror, soniska sensorer, infraröda sensorer och radar och lidarsystem används för i icke-förstörande tester. Bland alla olika sensorerhar radarsystem förmågan att tränga igenom byggda strukturer (dielektriskmaterial), vilket gör dem flexibla och lämpliga för ett brettspektrum av industriella och militära applikationer vid icke-förstörande avkänning. Sådana exempel är upptäckt av skador vid tillverkning av varor, övervakning av hälsa hos många strukturer, detektering av objekt genom väggen av säkerhetsskäl etc. Speciellt är radarsystem med ultrabredband (UWB) fördelaktiga då de ger hög mätnoggrannhet och samtidigt minskad känslighet mot passiva störningar (såsom regn, rök,dimma etc.), och immunitet mot yttre strålning och buller. Syftet med denna avhandling är : I) att undersöka elektriskt små dolda struktur med syntetisk bländaradar (SAR), II) att bestämma komplex brytningsindex för objekt som använder UWB radarsystem, ochIII) att svar på frågan hur vi kan minska den ömsesidiga kopplingen(överhörning) i ett UWB radarsystem med sändar- och mottagarantenner nära varandra. I mål I, är målet icke-förstörande provning avbyggda struktures såsom vid tillverkning av betongplattor eller vid renovering. I tillägg kunde inte elektriskt små strukturer och deras inre struktur urskiljas i konventionella SAR-bilder. Den föreslagna polarimetriskaanalysmetoden visar på hur användbar singulärvärdesuppdelning(SVD) med bakåtprojektion (BPA) är för att få information om och för att klassificera elektriskt små objekt.Vidare i denna avhandling visas för mål II en ny metod för att bestämma komplexa brytningsindex (eller motsvarande komplexa relativa permittiviteten) hos objekt med plana ytor. Den föreslagna metoden är relativt okänslig för svagheter hos hårdvaran, såsom frekvensberoende hos antennener och analog front-end. Objekten kan vara av ändlig storlek och på ändligt avstånd. Begränsningarna i storlek och avstånd för metoden att vara giltig undersöktes experimentellt. Sålunda är metoden utformad för industriella mätningar på föremål på transportband. I de följande delarna av avhandlingen - mål III - undersöker och visar vi dessutom hur en absorbator för mikrovågor, baserad på metamaterial, kan användas för att förbättra prestanda hos ett radarsystem för korta avstånd, när absorbatorn placeras mellan sändar- och mottagantenner. Resultatet blir att felet i det bestämda avståndet till målet minskar och undertryckning av klotter ökar.<br><p>QC 20210309</p>
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Abusultan, Monther Younis. "Digital implementation of direction-of-arrival estimation techniques for smart antenna systems." Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/abusultan/AbusultanM0510.pdf.
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Adaptive antenna arrays use multiple antenna elements to form directional patterns in order to improve the performance of wireless communication systems. The antenna arrays also have the ability to detect the direction of incoming signals. These two capabilities allow a smart antenna system to adaptively beamform to more efficiently communicate between nodes. The direction-of-arrival estimation is a crucial component of the smart antenna system that uses open-loop adaptive approach. Historically this estimation has been accomplished using a personal computer. Implementing the estimation in the digital domain has the potential to provide a low cost and light weight solution due to recent advances in digital integrated circuit fabrication processes. Furthermore, digital circuitry allows for more sophisticated estimation algorithms to be implemented using the computational power of modern digital devices. This thesis presents the design and prototyping of direction-of-arrival (DOA) estimation for a smart antenna system implemented on a reconfigurable digital hardware fabric. Two DOA estimation algorithms are implemented and the performance tradeoffs between a custom hardware approach and a microprocessor-based system are compared. The algorithms were implemented for a 5.8 GHz, 8-element circular antenna array and their functionality was verified using a testbed platform. The implementation and analysis presented in this work will aid system designers to understand the tradeoffs between implementing algorithms in custom hardware versus an embedded system and when a hybrid approach is more advantageous.
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Bouktache, Essaid. "Analysis of an adaptive antenna array with intermediate-frequency weighting partially implemented by digital processing /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260135357046.
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Fuster, Joel J. "A hardware architecture for real-time beamforming." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0005060.
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Qian, Rongrong. "The electronically steerable parasitic array radiator antenna for wireless communications : signal processing and emerging techniques." Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/3001.
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Smart antenna technology is expected to play an important role in future wireless communication networks in order to use the spectrum efficiently, improve the quality of service, reduce the costs of establishing new wireless paradigms and reduce the energy consumption in wireless networks. Generally, smart antennas exploit multiple widely spaced active elements, which are connected to separate radio frequency (RF) chains. Therefore, they are only applicable to base stations (BSs) and access points, by contrast with modern compact wireless terminals with constraints on size, power and complexity. This dissertation considers an alternative smart antenna system the electronically steerable parasitic array radiator (ESPAR) which uses only a single RF chain, coupled with multiple parasitic elements. The ESPAR antenna is of significant interest because of its flexibility in beamforming by tuning a number of easy-to-implement reactance loads connected to parasitic elements; however, parasitic elements require no expensive RF circuits. This work concentrates on the study of the ESPAR antenna for compact transceivers in order to achieve some emerging techniques in wireless communications. The work begins by presenting the work principle and modeling of the ESPAR antenna and describes the reactance-domain signal processing that is suited to the single active antenna array, which are fundamental factors throughout this thesis. The major contribution in this chapter is the adaptive beamforming method based on the ESPAR antenna. In order to achieve fast convergent beamforming for the ESPAR antenna, a modified minimum variance distortionless response (MVDR) beamfomer is proposed. With reactance-domain signal processing, the ESPAR array obtains a correlation matrix of receive signals as the input to the MVDR optimization problem. To design a set of feasible reactance loads for a desired beampattern, the MVDR optimization problem is reformulated as a convex optimization problem constraining an optimized weight vector close to a feasible solution. Finally, the necessary reactance loads are optimized by iterating the convex problem and a simple projector. In addition, the generic algorithm-based beamforming method has also studied for the ESPAR antenna. Blind interference alignment (BIA) is a promising technique for providing an optimal degree of freedom in a multi-user, multiple-inputsingle-output broadcast channel, without the requirements of channel state information at the transmitters. Its key is antenna mode switching at the receive antenna. The ESPAR antenna is able to provide a practical solution to beampattern switching (one kind of antenna mode switching) for the implementation of BIA. In this chapter, three beamforming methods are proposed for providing the required number of beampatterns that are exploited across one super symbol for creating the channel fluctuation patterns seen by receivers. These manually created channel fluctuation patterns are jointly combined with the designed spacetime precoding in order to align the inter-user interference. Furthermore, the directional beampatterns designed in the ESPAR antenna are demonstrated to improve the performance of BIA by alleviating the noise amplification. The ESPAR antenna is studied as the solution to interference mitigation in small cell networks. Specifically, ESPARs analog beamforming presented in the previous chapter is exploited to suppress inter-cell interference for the system scenario, scheduling only one user to be served by each small BS at a single time. In addition, the ESPAR-based BIA is employed to mitigate both inter-cell and intracell interference for the system scenario, scheduling a small number of users to be simultaneously served by each small BS for a single time. In the cognitive radio (CR) paradigm, the ESPAR antenna is employed for spatial spectrum sensing in order to utilize the new angle dimension in the spectrum space besides the conventional frequency, time and space dimensions. The twostage spatial spectrum sensing method is proposed based on the ESPAR antenna being targeted at identifying white spectrum space, including the new angle dimension. At the first stage, the occupancy of a specific frequency band is detected by conventional spectrum-sensing methods, including energy detector and eigenvalue-based methods implemented with the switched-beam ESPAR antenna. With the presence of primary users, their directions are estimated at the second stage, by high-resolution angle-of-arrival (AoA) estimation algorithms. Specifically, the compressive sensing technology has been studied for AoA detection with the ESPAR antenna, which is demonstrated to provide high-resolution estimation results and even to outperform the reactance-domain multiple signal classification.
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Caba, Wilson Ariel. "Application of antenna synthesis and digital signal processing techniques for active millimeter-wave imaging systems." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4532.
Full textAbstract:
Millimeter-wave imaging has gathered attention in recent years for its ability to penetrate clothing, thin layers of soils, and certain construction materials. However, image quality remains a challenge that needs to be addressed. One way of improving image quality is by increasing the dimensions of the collecting aperture. A sparse array can be used to synthesize a larger aperture with a limited set of relatively small detectors. In this research we design, build, and test a test-bed having an active source at 94 GHz and an array of coherent detectors, mounted on arms that extend radially on a rotary table. Using this test bed a circular area with a maximum diameter of 900 mm can be scanned. The signal is down-converted using heterodyne receivers with digital in-phase and quadrature detection. Signal correlation is performed using the digitized data, which is stored for post-processing, electronic focusing, and image reconstruction. Near-field imaging using interferometric reconstructions is achieved using electronic focusing. Imaging tests show the ability of the system to generate imagery of concealed and unconcealed objects at distances between 400 and 700 mm. A study of the effects of redundant and non-redundant configurations on image quality for 4 common detector configurations is presented. In this document we show that an active sparse-aperture imaging system using digital correlators is a viable way to generate millimeter-wave images.<br>ID: 029050356; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2010.; Includes bibliographical references (p. 125-129).<br>Ph.D.<br>Doctorate<br>Optics and Photonics
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Quist, Britton T. "Improved Channel Probing for Secret Key Generation with Multiple Antenna Systems." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3554.
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Establishing secret keys from the commonly-observed randomness of reciprocal wireless propagation channels has recently received considerable attention. In this work we propose improved strategies for channel estimation between MIMO or beamforming systems for secret key generation. The amount of mutual information that can be extracted from the channel matrix estimates is determined by the quality of channel matrix estimates. By allocating increased energy to channel estimation for higher gain beamforming combinations at the expense of low-gain combinations, key establishment performance can be increased. Formalizing the notion of preferential energy allocation to the most efficient excitations is the central theme of this dissertation. For probing with beamforming systems, we formulate a theoretically optimal probing strategy that upper bounds the number of key bits that can be generated from reciprocal channel observations. Specifically, we demonstrate that the eigenvectors of the channel spatial covariance matrix should be used as beamformer weights during channel estimation and we optimize the energy allocated to channel estimation for each beamformer weight under a total energy constraint. The optimal probing strategy is not directly implementable in practice, and therefore we propose two different modifications to the optimal algorithm based on a Kronecker approximation to the spatial covariance matrix. Though these approximations are suboptimal, they each perform well relative to the upper bound. To explore how effective an array is at extracting all of the information available in the propagation environment connecting two nodes, we apply the optimal beamformer probing strategy to a vector current basis function expansion on the array volume. We prove that the resulting key rate is a key rate spatial bound that upper bounds the key rate achievable by any set of antenna arrays probing the channel with the same total energy constraint. For MIMO systems we assume the channel is separable with a Kronecker model, and then for that model we propose an improved probing strategy that iteratively optimizes the energy allocation for each node using concave maximization. The performance of this iterative approach is better than that achieved using the traditional probing strategy in many realistic probing scenarios.
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Johnson, Sandra Gomulka. "Antenna array output power minimization using steepest descent adaptive algorithm." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000561.
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Zhu, Danny. "Source localization within a uniform circular sensor array /." Online version of thesis, 2007. http://hdl.handle.net/1850/4628.
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Hedlund, Richard. "Design of a UAV-based radio receiver for avalanche beacon detection using software defined radio and signal processing." Thesis, Uppsala universitet, Signaler och System, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-377025.
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A fully functional proof of concept radio receiver for detecting avalanche beacons atthe frequency 457 kHz was constructed in the work of this master thesis. The radioreceiver is intended to be mounted on an unmanned aerial vehicle (UAV or drone)and used to aid the mountain rescue teams by reducing the rescue time in findingavalanche victims carrying a transmitting beacon. The main parts of this master thesisinvolved hardware requirement analysis, software development, digital signalprocessing and wireless communications. The radio receiver was customized to receive low power signal levels becausemagnetic antennas are used and the avalanche beacon will operate in the reactive nearfield of the radio receiver. Noise from external sources has a significant impact on theperformance of the radio receiver. This master thesis allows for straightforward further development and refining of theradio receiver due to the flexibility of the used open-source software development kitGNU Radio where the digital signal processing was performed.
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Haustein, Thomas. "Real time signal processing for Multi-Antenna systems and experimental verification on a reconfigurable Hardware test bed." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982095287.
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Wilzeck, Andreas. "A software defined radio approach for high data rate multi-antenna wireless communications with frequency domain processing." Aachen Shaker, 2009. http://d-nb.info/997951338/04.
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SHI, YU. "Enhanced SAR Image Processing Using A Heterogeneous Multiprocessor." Thesis, Linköping University, Department of Computer and Information Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11517.
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<p>Synthetic antenna aperture (SAR) is a pulses focusing airborne radar which can achieve high resolution radar image. A number of image process algorithms have been developed for this kind of radar, but the calculation burden is still heavy. So the image processing of SAR is normally performed “off-line”.</p><p>The Fast Factorized Back Projection (FFBP) algorithm is considered as a computationally efficient algorithm for image formation in SAR, and several applications have been implemented which try to make the process “on-line”.</p><p>CELL Broadband Engine is one of the newest multi-core-processor jointly developed by Sony, Toshiba and IBM. CELL is good at parallel computation and floating point numbers, which all fit the demands of SAR image formation.</p><p>This thesis is going to implement FFBP algorithm on CELL Broadband Engine, and compare the results with pre-projects. In this project, we try to make it possible to perform SAR image formation in real-time.</p>
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Flint, Keith D., Gregory P. Mathis, and Tom G. Cronauer. "The Phillips Laboratory's Mobile Ground Telemetry Station (MGTS) Configuration and Operations." International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/611830.
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International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada<br>In support of the various programs that the Phillips Laboratory's Space Experiments Directorate is conducting for the Ballistic Missile Defense Organization (BMDO), the Range Operations Division is developing a mobile telemetry processing system as part of the Mobile Ground Telemetry Station (MGTS) program. The MGTS program's goals are to develop a mission-dedicated telemetry system to supplement current test range capabilities by receiving, processing and recording multiple data streams, sometimes exceeding 10 Mbps. The system will support airborne and suborbital vehicles as well as customized satellite downlinks designed for spacecraft bus State-of-Health monitoring and sensor payload observations. Autonomy and off-road capabilities are also important factors since some of the operations envisioned require deployment to remote field locations where no telemetry processing capabilities currently exist to support the unique data handling requirements. The Phillips Laboratory has completed, with support from Wyle Laboratories and Systems Engineering and Management Company (SEMCO), a "proof-of-concept" mobile telemetry processing system referred to as MGTS #2. Demonstration of the system has been accomplished with the successful deployment and operational support provided to both BMDO's Lightweight Exo-Atmospheric Projectile (LEAP) sub-orbital missions and Miniature Sensor Technology Integration (MSTI) satellite program. MGTS #2 has deployed and is scheduled for further deployment to various operating sites including: White Sands Missile Range (WSMR), NM; Air Force Flight Test Center (AFFTC), Edwards AFB, CA; Vandenberg AFB, CA; and NASA's Wallops Island Flight Facility, VA. While deployed MGTS #2 processes, records and rapidly distributes the critical mission telemetry data conforming to both IRIG and SGLS standards. This paper will describe the evolution of the MGTS program, current hardware configurations and the various mission scenarios that have been supported by the MGTS team.
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Bansal, Mayur. "DIGITAL CONTROL BOARD FOR PHASED ARRAY ANTENNA BEAM STEERING IN ADAPTIVE COMMUNICATION APPLICATIONS." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1113.
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The application of adaptive communication techniques for mobile communications has attracted considerable interest in the last decade. One example of these techniques is spatial filtering through planar antenna array beam forming.
This thesis describes the development of a digital system that adaptively controls a phased array antenna. The radiating structure of the phased antenna array is tetrahedral-shaped and contains four antenna elements on each of its three faces. The overall system comprises of a digital control board with an external computer interface, an RF control board, and the phased antenna array. The RF controls the main lobe direction on the phased array antenna. This thesis describes the design and implementation of the digital control board.
The digital control board`s primary responsibilities are implementing inter- faces between the external computer and the RF board, which results in two operational modes: the MATLAB graphical user interface (GUI) mode and the adaptive receive mode. The GUI mode allows users to input parameters that provide interactive control of the phased antenna array by interfacing with an external computer and the RF control board. The adaptive receive mode im- plements an algorithm for an adaptive receive station. This algorithm uses a 58-point scanning technique that locates the maximum receive power direction.
Test results show that the digital control board successfully manages the RF board control voltage with an nominal error of less than 1%, which subsequently allows for precise control of the antenna`s active face. Additionally, testing of the GUI demonstrated the successful interactive application of various system control parameters.
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Alkhafaji, Nasr Nomas Hussein. "UHF and Microwave Phase-Modulated Scattering Array." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/4998.
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This dissertation investigates the use an array of active nonlinear elements, with particular emphasis on controlling distortion products generated by nonlinear elements in space rather than using conventional ways such as transmission lines, waveguides, and power dividers and combiners. The nonlinear elements are made of assemblies of antennas and electronic switches, called modulated scatterers (MSs). These so-called MSs elements are utilized in a wide variety of applications such as radio frequency identification (RFID) systems, microwave imaging, Internet-of-Things sensors, etc. However, no research work has been reported in the literature regarding exploiting and controlling several distortion products generated by MSs at the same time according to the best of authors' knowledge. To facilitate controlling distortion products which means suppressing or enhancing distortion products in space, we present a nonlinear array with elements that are MSs instead of conventional antennas. MSs are switched ON-OFF at different times by modulation signals having the same frequency. The time delay of the switching process between array elements represents a relative phase shift difference in the frequency domain. Thus, the presented structure is called the phase-modulated scattering array (PMSA). The PMSA has a similar layout of phased arrays, but it does not have a feeding network and is fed by an external source called the illuminating source. Because our system does not need a feeding network and phase shifters, it is potentially easier to implement with low cost. Two different signals which are the illuminating (incident) and modulation signals interact inside switches to generate a huge number of distortion products due to the nonlinearity of switches and the periodic nature of the presented system. Distortion products then leave the presented PMSA to space again (i.e., scattering distortion products). The PMSA is able to treat distortion products and achieve beamforming functions.
The operation mechanism of the PMSA is explained by developing two different mathematical models. Communication signal processing perspectives are the basis of the first mathematical model developed to show the spatial characteristics of distortion products generated by our presented PMSA. Its root is originated from a mathematical model of the widely-used polyphase multipath technique in RF communication circuits. However, the adopted technique is suitable only for communication circuits with a single output and parameters prescribed in advance. Thus, the model is further developed to circumvent all the problems mentioned above and to be able to detect the spatial characteristics of distortion products at any point in space. Static impacts of the measurement environment, real radiation patterns of actual antennas utilized in prototypes, and phase and gain errors among paths have been taken into account as well. In the model, every single scatterer is represented by a single separate path. Furthermore, the modified model is extended to include single, two, and multi tones modulation signals. Simulation results have been obtained before and after the modification for a different number of paths and modulation signals with different tones. Results show that the modified model can quantify spatial characteristics of distortion products at any point in space where specific distortion products are enhanced, and others are canceled. Because distortion products are independent in their nature (i.e., each single distortion product has different frequency and phase), they have independent radiation patterns (scattered beams). Therefore, the second mathematical model based on phased antenna array perspectives is developed. The relationship between the two models states that a distortion product which is enhanced at a certain point in space has a maximum scattered beam at that point. Also, the second mathematical model being similar to mathematical models of phased arrays considers effects of all distortion products resulting from single, two, and multi tones modulation signals, and it states that each single distortion component has its particular scattered beam.
Next, sub-models for some properties and applications of the presented PMSA such as a diffraction grating-like behavior, nonreciprocity, beamforming, a tool for distortion product analysis of phased arrays and multi-input multi-output (MIMO systems), a reconfigurable-spatial harmonic generator, and a direction finding technique are derived depending on the two main mathematical models. All parts are simulated and results validate all proposed functionalities.
Single antennas, antenna arrays, electronic switches (modulators), and a 4-to-8 phase transformer kit using only resistors have been designed, simulated, fabricated, assembled, and tested.
Eventually, different structures of the presented PMSAs working at 432MHz and 2.3GHz are tested inside the anechoic chamber. Both frequencies are downconverted to the band 2-22kHz. Modulation signals used in the experimental setups are single and two tones. Data are measured using the commercial software SigView running on a laptop and a spectrum analyzer. Both spatial characteristics and scattered beams of distortion products are measured. Comparisons have been made between measured received responses of scattered signals and theoretical results. They are in good agreement although limitations and challenges are encountered with each round of measurement. Measured results confirm practically that as a number of scatterers increases, more distortion products are controlled at the same time. The distortion product rejection ratio DPRR is more than 15dB for all measured distortion products supposed to be canceled. Directions of scattered beams are found at expected locations with errors less than 3%. Furthermore, directions of illuminating signals or distances separating between PMSA elements are varied to change directions of scattered beams when prescribed values of parameters governing the overall performance are being broken. In other words, the beamforming functionality has been validated practically. Different elements of 8*1-PMSA are turned-off at measurements in order to find fault tolerances of the presented system. Measured results show that when two elements are failed simultaneously, responses can be accepted to some extent.