Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: This thesis describes the development of attitude sensors required for the Attitude Determination and Control System (ADCS) for a Cubesat. The aim is to find the most suitable sensors for use on a small picosatellite by implementing miniaturised sensors with available commercial-off-the-shelf (COTS) technology. Specifically, the algorithms, hardware prototypes, software and filters required to create accurate sensors to determine the 3-axis orientation of a CubeSat are discussed. / AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die ontwikkeling van oriëntasiesensors wat benodig word vir die oriëntasiebepaling en -beheerstelsel (Engels: ADCS) van ’n CubeSat. Die doelwit is om sensors te vind wat die geskikste is om in ’n klein picosatelliet te gebruik, deur miniatuursensors met kommersiële maklik verkrygbare tegnologie (Engels: COTS technology) te implementeer. Daar word in die bespreking veral aandag geskenk aan die algoritmes, hardewareprototipes, programmatuur en filters wat benodig word om akkurate sensors te skep wat op hul beurt 3-as oriëntasie van die CubeSat kan bepaal.

The Cal Poly CubeSat Laboratory (CPCL) is currently facing unprecedented engineering challenges—both technically and programmatically—due to the increasing cost and complexity of CubeSat flight missions. In responding to recent RFPs, the CPCL has been forced to find commercially available solutions to entire mission critical spacecraft subsystems such as propulsion and attitude determination & control, because currently no in-house options exist for consideration. The commercially available solutions for these subsystems are often extremely expensive and sometimes provide excessively good performance with respect to mission requirements. Furthermore, use of entire commercial subsystems detracts from the hands-on learning objectives of the CPCL by removing engineering responsibility from students. Therefore, if these particular subsystems can be designed, tested, and integrated in-house at Cal Poly, the result would be twofold: 1) the space of missions supportable by the CPCL under tight budget constraints will grow, and 2) students will be provided with unique, hands-on guidance, navigation, and control learning opportunities. In this thesis, the CPCL’s attitude determination and control system design and analysis toolkit is significantly improved to support in-house ADCS development. The toolkit—including the improvements presented in this work—is then used to complete the existing, partially complete CPCL ADCS design. To fill in missing gaps, particular emphasis is placed on guidance and control algorithm design and selection of attitude actuators. Simulation results show that the completed design is competitive for use in a large class of small satellite missions for which pointing accuracy requirements are on the order of a few degrees.

In der vorliegenden Arbeit wird eine modulare Reaktionssequenz von zwei aufeinanderfolgenden chemoselektiven Umwandlungen vorgestellt: Es wird gezeigt, dass Vinyl- und Ethynylphosphonamidate chemoselektiv mit Cysteinen von Proteinen und Antikörpern reagieren. Weiterhin wird gezeigt, dass elektrophile Phosphonamidate durch eine vorhergehende chemoselektive Staudinger-Phosphonit Reaktion zwischen Aziden und ungesättigten Phosphoniten in das gewünschte Molekül eingebaut werden können. Hierbei wird ein elektronenreiches Phosphonit in ein elektronenarmes Phosphonamidat umgewandelt, welches somit für die nachfolgende Thiol-Addition aktiviert wird. Die beschriebene Methode erweitert das bestehende Repertoire von Biokonjugationen durch die Einführung eines neuen Konzepts: Eine chemoleselektive Reaktion, die Reaktivität für eine nachfolgende Biokonjugation induziert. Da Phosphonamidat-Konjugationen an Cysteine herausragende Eigenschaften, wie hohe Selektivität für Cysteine, saubere Reaktionsprodukte und eine hervorragende Stabilität mitbringen, wird im zweiten Teil beschrieben wie Phosphonamidate für die Anbindung von zytotoxischen Wirkstoffen an tumor-bindende Antikörper genutzt werden können um Antikörper-Wirkstoff-Konjugate (ADCs) herzustellen. Ein einfaches Syntheseprotokoll für die Herstellung, ausgehend von einem nicht gentechnisch veränderten Antikörper mit nur geringen Überschüssen des Wirkstoffs wird vorgestellt. Phosphonamidat-verbundene ADCs zeigen im direkten Vergleichen zum zugelassenen, Maleimid-verbundenen Adcetris überlegende Eigenschaften, wie eine erhöhte Stabilität in Serum und eine erhöhte in vivo Wirksamkeit in einem Tumor Mausmodel. Zusammenfassend verbindet die hier vorgestellte Methode einen einfachen synthetischen Zugang mit hoher Selektivität, überragender Konjugat-Stabilität und der Möglichkeit hochwirksame Wirkstoffkonjugate herzustellen und wird daher aller Voraussicht nach einen großen Beitrag zum Gebiet der zielgerichteten Therapie leisten. / The present work introduces a modular reaction sequence of two chemoselective manipulations in a row. It is shown that vinyl- and ethynylphosphonamidates react selectively with cysteine residues on proteins and antibodies. Most importantly, those electrophilic phosphonamidates can be incorporated into a given molecule in another preceding chemoselective Staudinger-phosphonite reaction (SPhR) from unsaturated phosphonites and azides. During this reaction, an electron-rich phosphonite is transformed into an electron-deficient phosphonamidate that is thereby activated for the subsequent thiol addition. The described technique thereby extends the existing repertoire of bioconjugations by introducing a new concept in protein synthesis: A chemoselective reaction that induces reactivity for a subsequent bioconjugation. Since phosphonamidate conjugations to cysteine hold outstanding features such as high selectivity for cysteine, clean reaction products and excellent stability of the protein adducts in biological environments, it is described in the second part of the present work how ethynylphosphonamidates can be employed for the conjunction of tumor-sensing antibodies and cytotoxic drugs to generate Antibody-Drug-Conjugates (ADCs). A simple synthetic protocol starting from unengineered antibodies, using only a slight excess of the desired drug in a one-pot synthesis protocol is introduced. In a direct comparison to the maleimide containing FDA-approved Adcetris, phosphonamidate linked ADCs show a superior behaviour in terms of linkage stability in serum, combined with an increased in vivo efficacy in a tumor xenograft mouse model. Taken together, the method described herein combines simple synthetic access with high selectivity, superior conjugate stability and the possibility to synthesize highly efficacious drug conjugates and is therefore likely to have a great contribution to the field of targeted therapeutics.

[pt] Sistemas de múltiplas antenas de larga escala são técnicas fundamentais para sistemas de comunicação sem fio do futuro, que deverão servir dezenas de usuários por estação rádio-base. Neste contexto, um problema chave é o aumento do consumo de energia à medida que o número de antenas cresce. Recentemente, CADs de baixa resolução têm atraído grande interesse de pesquisa. Em particular, CADs de 1 bit são adequados para sistemas de larga escala devido ao seu baixo custo e consumo de energia. Nesta tese, CADs de 1 bit são usados em três diferentes abordagens de projeto, que operam a taxa de Nyquist e a taxas superiores a taxa de Nyquist com estratégias de amostragem uniforme e dinâmica. Nos sistemas operando a taxa de Nyquist, algoritmos de estimação de canal que exploram o conhecimento da baixa resolução e um novo esquema de detecção e decodificação iterativas são propostos, em que códigos low-density paritycheck de bloco curto são considerados para evitar alta latência. Nos sistemas operando a taxas superiores a taxa de Nyquist com sobreamostragem uniforme, algoritmos eficientes de estimação de canal e de detecção com janela deslizante com exploração da baixa resolução são propostos. Além disso, são deduzidas expressões analíticas associadas aos limitantes de Cramér-Rao para os sistemas com sobreamostragem. Resultados numéricos ilustram o desempenho dos algoritmos de estimação de canal propostos e existentes e os limitantes teóricos deduzidos. Nos sistemas operando com sobreamostragem dinâmica, duas abordagens de projeto são desenvolvidas: uma técnica baseada na maximização da soma das taxas e uma técnica baseada na minimização do erro médio quadrático. Em seguida, três algoritmos de redução de dimensão são apresentados e investigados. Resultados de simulações mostram que os sistemas com sobreamostragem dinâmica têm melhor desempenho do que os sistemas com sobreamostragem uniforme em termos de soma das taxas alcançáveis e de taxa de erro de símbolos, enquanto o custo computacional das técnicas examinadas é comparável. / [en] Large-scale multiple-antenna systems are a key technique for future wireless communications, which will serve tens of users per base station (BS). In this scenario, one problem faced is the large energy consumption as the number of receive antennas scales up. Recently, low-resolution analogto-digital converters (ADCs) have attracted much attention. Specifically, 1-bit ADCs in the front-end are suitable for such systems due to their low cost and low energy consumption. In this thesis, 1-bit ADCs are applied in three different system designs, which operate at the Nyquist rate and faster than Nyquist rates along with uniform and dynamic strategies. In the Nyquist-sampling system, low-resolution-aware channel estimation algorithms and a novel iterative detection and decoding scheme are proposed, where short block length low-density parity-check codes are considered for avoiding high latency. In the faster than Nyquist rates with uniform oversampling system, lowresolution-aware channel estimation and sliding window based detection algorithms are proposed due to their low computational cost and high detection accuracy. Particularly, analytical expressions associated with the Bayesian Cramér-Rao bounds for the oversampled systems are presented. Numerical results are provided to illustrate the performance of the proposed channel estimation algorithms and the derived theoretical bounds. In the dynamic-oversampling system, two different system designs are devised, namely, sum rate and mean square error based. Three different dimension reduction algorithms are presented and thoroughly investigated. Simulation results show that the systems with the proposed dynamic oversampling outperform the uniformly oversampled system in terms of the computational cost, achievable sum rate and symbol error rate performance.

A comprehensive and scalable solution for high-performance switched capacitor amplification is presented. Central to this discussion is the concept of ring amplification. A ring amplifier is a small modular amplifier derived from a ring oscillator that naturally embodies all the essential elements of scalability. It can amplify with accurate rail-to-rail output swing, drive large capacitive loads with extreme efficiency using slew-based charging, naturally scale in performance according to process trends, and is simple enough to be quickly constructed from only a handful of inverters, capacitors, and switches. In addition, the gain-enhancement technique of Split-CLS is introduced, and used to extend the efficacy of ring amplifiers in specific and other amplifiers in general. Four different pipelined ADC designs are presented which explore the practical implementation options and design considerations relevant to ring amplification and Split-CLS, and are used to establish ring amplification as a new paradigm for scalable amplification. / Graduation date: 2012 / Access restricted to the OSU Community, at author's request, from July 19, 2012 - July 19, 2013

La thèse présente le développement de CPS (CMOS Pixel Sensors) intégré avec CAN au niveau du pixel pour les couches externes du détecteur de vertex de l’ILD (International Large Detector). Motivé par la physique dans l’ILC (International Linear Collider), une précision élevée est nécessaire pour les détecteurs. La priorité des capteurs qui montre sur les couches externes est une faible consommation d’énergie en raison du rapport élevé de couverture de la surface sensible (~90%) dans le détecteur de vertex. Le CPS intégré avec CAN est un choix approprié pour cette application. L’architecture de CAN de niveau colonne ne fournit pas une performance optimisée en termes de bruit et la consommation d’énergie. La conception de CAN au niveau du pixel a été proposée. Bénéficiant des sorties de pixels tout-numérique, CAN au niveau des pixels présentent les mérites évidents sur le bruit, la vitesse, la zone sensible et la consommation d’énergie. Un prototype de capteur, appelé MIMADC, a été implémenté par un processus de 0.18 μm CIS (CMOS Image Sensor). L’objectif de ce capteur est de vérifier la faisabilité du CPS intégré avec les CAN au niveau des pixels. Trois matrices sont incluses dans ce prototype, mais avec deux types différents de CAN au niveau de pixel: une avec des CAN à registre à approximations successives (SAR), et les deux autres avec des CAN à une seule pente (Single-Slope, SS) CAN. Toutes les trois possédant les pixels de la même taille de 35×35 μm2 et une résolution de 3-bit. Dans ce texte, des analyses théoriques et le prototype sont présentés, ainsi que la conception détaille des circuits. / This thesis presents the development of CMOS pixel sensors (CPS) integrated with pixel-level ADCs for the outer layers of the ILD (International Large Detector) vertex detector. Driven by physics in the ILC (International Linear Collider), an unprecedented precision is required for the detectors. The priority of the sensors mounted on the outer layers is low power consumption due to the large coverage ratio of the sensitive area (~90%) in the vertex detector. The CPS integrated with ADCs is a promising candidate for this application. The architecture of column-level ADCs, exists but do not provide an optimized performance in terms of noise and power consumption. The concept of pixel-level ADCs has been proposed. Benefiting from the all-digital pixel outputs, pixel-level ADCs exhibit the obvious merits on noise, speed, insensitive area, and power consumption. In this thesis, a prototype sensor, called MIMADC, has been implemented by a 0.18 μm CIS (CMOS Image Sensor) process. The target of this sensor is to verify the feasibility of the CPS integrated with pixel-level ADCs. Three matrices are included in this prototype but with two different types of pixel-level ADCs: one with successive approximation register (SAR) ADCs, and the other two with single-slope (SS) ADCs. All of them feature a same pixel size of 35×35 μm2 and a resolution of 3-bit. In this thesis, the prototype is presented for both theoretical analyses and circuit designs. The test results of the prototype are also presented.

Over recent years, the research and studies have focused on innovative solutions in various aspects and phases related to the high demands on data rate and energy for fifth-generation and beyond (B5G). This thesis aims to improve the energy efficiency, error rates, low-resolution ADCs/DACs, antenna array structures and sum-rate performances of a single cell downlink broadband millimetre-wave (mmWave) systems with orthogonal frequency division multiplexing (OFDM) modulation and deploying multi-user massive multiple inputs multiple outputs (MU mMIMO) by applying robust beamforming techniques and detection algorithms that support multiple streams per user (UE) in various environments and scenarios to achieve low complexity system design with reliable performance and significant improvement in users perceived quality of service (QoS). The performance of the four 5G candidate mmWave frequencies, 28 GHz, 39 GHz, 60 GHz, and 73 GHz, are investigated for indoor/outdoor propagation scenarios, including path loss models and multipath delay spread values. Results are compared to confirm that the received power and delay spread is decreased with increasing frequency. The results were also validated with the measurement findings for 60 GHz. Then several proposed design models of beamforming are studied and implemented modified algorithms of Hybrid Beamforming (HBF) approaches in indoor/outdoor scenarios over large scale fading wideband mmWave /Raleigh channels. Firstly, three beamforming based diagonalize the Equivalent Virtual Channel Matrix (EVCM) schemes with the optimal linear combining methods are presented to overcoming the self-interference problems in Quasi-Orthogonal-Space Time Block Code (QO-STBC) systems over narrowband mmWave Single-User mMIMO (SU mMIMO). The evaluated results show that the proposed beamforming based- Single Value Decomposition (SVD) outperforms the conventional beamforming and standard QO-STBC techniques in terms of BER and spectrum efficiency. Next, the proposed HBF algorithm approaches with the fully/ partially connected structures are developed and applied for sum-rate and symbol error rate (SER) performance maximization MU mMIMO-OFDM system, including HBF based on block diagonalization (BD) method Constraint/Unconstraint RF Power, Codebook, Kalman schemes. In addition, the modified near optimal linear HBF-Zero Forcing (HBF-ZF) and HBF-Minimum Mean Square Error (HBF MMSE) schemes, considering both fully-connected and partially-connected structures. Finally, Simulation results using MATLAB platform, demonstrate that the proposed HBF based codebook and most likely HBF based-unconstraint RF power algorithms achieve significant performance gains in terms SER and sum-rate efficiency as well as show high immunity against the deformities and disturbances in the system compared with other HBF algorithm schemes. / Ministry of Higher Education and Scientific Research, the Republic of Iraq