Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

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<p> Detection and estimation of multiple unresolved targets with a monopulse radar is a challenging problem. For ideal single bin processing, it was shown in the literature that at most two unresolved targets can be extracted from the complex matched filter output signal. In this thesis, a new algorithm is developed to jointly detect and track more than two targets from a single detection. This method involves the use of tracking data in the detection process. For this purpose, target states are transformed into the detection parameter space, which involves high nonlinearity. In order to handle this, the sequential Monte Carlo (SMC) method, which has proven to be effective in nonlinear non-Gaussian estimation problems, is used as the basis of the closed loop system for tracking multiple unresolved targets. In addition to the standard SMC steps, the detection parameters corresponding to the predicted particles are evaluated using the nonlinear monopulse radar beam model. This in turn enables the evaluation of the likelihood of the monopulse signal given tracking data. Hypothesis testing is then used to find the correct detection event. The particles are updated and resampled according to the hypothesis that has the highest likelihood (score). A simulated amplitude comparison monopulse radar is used to generate the data and to validate the extraction and tracking of more than two unresolved targets.</p> / Thesis / Master of Applied Science (MASc)

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / This thesis documents the design and implementation of an S-band receiver for phasecomparison monopulse radar. The design and evaluation of the various sub-systems involved in realizing the receiver are discussed in detail. The designed sub-systems are connected via low loss coaxial cables to form the complete phase-comparison monopulse radar receiver. The performance of the receiver is evaluated and compared with the theoretical results, in terms of frequency response, gain and noise figure. The designed receiver is finally connected to an existing antenna system, and a preliminary test of the complete radar is performed. The initial results show that the design is successful, but the boresight-axis of the radar has shifted in angle and requires pre-comparator phase shifting in order to obtain accurate tracking. ii

As part of the processing of tracking targets, surveillance radars detect the presence of targets and estimate their locations. This dissertation re-examines some of the often ignored practical considerations of radar tracking. With the advent of digital computers, modern radars now use sampled versions of received signals for processing. Sampling rates used in practice result in the bin-straddling phenomenon, which is often treated as an undesired loss in signal power. Here, a signal model that explicitly models the sampling process is used in the derivation of the average loglikelihood ratio test (ALLRT), and its detection performance is shown to defeat the bin-straddling losses seen in traditional radar detectors. In monopulse systems, data samples are taken from the sum and difference channels, by which a target direction-of-arrival (DOA) estimate can be formed. Using the same signal model, we derive new estimators for target range, strength, and DOA and show performance benefits over traditional monopulse techniques that are predominant in practice. Since tracking algorithms require an error variance report on target parameter estimates, we propose using the generalized Cramer-Rao lower bound (GCRLB), which is the CRLB evaluated at estimates rather than true values, as an error variance report. We demonstrate the statistical efficiency and variance consistency of the new estimators. With several parameter estimates collected over time, tracking algorithms are used to compute track state estimates and predict future locations. Using agile- beam surveillance radars with programmable energy waveforms, optimal scheduling of radar resources is a topic of interest. In this dissertation, we focus on the energy management considerations of tracking highly maneuverable aircraft. A comparison between two competing interacting multiple model (IMM) filter configurations is made, and a recently proposed unbiased mixing procedure is extended to the case of three modes. Finally, we introduce the radar management operating curve (RMOC), which shows the fundamental tradeoff in radar time and energy, to aid radar designers in the selection of an overall operating signal-to-noise level.

Cross-eye jamming is an Electronic Attack (EA) technique that induces an angular error in the radar being jammed. The main benefit of cross-eye jamming is that it is effective against monopulse tracking radars, which are largely immune to other forms of jamming. The objective of this research is to gain a complete understanding of cross-eye jamming so that systems that might be developed in future can be properly specied. The main contribution of this work is a comprehensive mathematical and experimental study of retrodirective cross-eye jamming. The mathematical analysis considers all aspects of an isolated, single-loop, retrodirective cross-eye jamming engagement, thereby avoiding the approximations inherent in other cross-eye jamming analyses. Laboratory experiments that accurately represent reality by using the radar for both transmission and reception, and simulating a true retrodirective cross-eye jammer were performed to validate the theoretical analysis. Lastly, the relationship between the angular error induced in the radar being jammed and the matching required from a cross-eye jammer system is explored. The most important conclusion of this work is that the traditional analyses of cross- eye jamming are inaccurate for the conditions under which cross-eye jammers operate. These inaccuracies mean that the traditional analyses are overly conservative, particularly at short ranges and for high cross-eye gains, suggesting that practical cross-eye jammers can be realised more easily than is generally believed. / Thesis (PhD)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted

The development of millimeter-wave (30-300 GHz) sensors and communications systems has a long history of interest, spanning back almost six decades. In particular, mm-wave radars have applications as automotive radars, in remote atmospheric sensing applications, as landing radars for air and spacecraft, and for high precision imaging applications. Mm-wave radar systems have high angular accuracy and range resolution, and, while susceptible to atmospheric attenuation, are less susceptible to optically opaque conditions, such as smoke or dust. This dissertation document will present the initial steps towards a new approach to the creation of a mm-wave radar system at 94 GHz. Specifically, this dissertation presents the design, fabrication and testing of various components of a highly integrated mm-wave a 94 Ghz monopulse radar transmitter/receiver. Several architectural approaches are considered, including passive and active implementations of RF monopulse comparator networks. These architectures are enabled by a high-performance three-dimensional rectangular coaxial microwave transmission line technology known as PolyStrataTM as well as silicon-based IC technologies. A number of specific components are examined in detail, including: a 2x2 PolyStrata antenna array, a passive monopulse comparator network, a 94 GHz SiGe two-port active comparator MMIC, a 24 GHz RF-CMOS 4-port active monopulse comparator IC, and a series of V- and W-band corporate combining structures for use in transmitter power combining applications. The 94 GHz cavity-backed antennas based on a rectangular coaxial feeding network have been designed, fabricated, and tested. 13 dB gain for a 2 x 2 array, as well as antenna patterns are reported. In an effort to facilitate high-accuracy measurement of the antenna array, an E-probe transition to waveguide and PolyStrata diode detectors were also designed and fabricated. AW-band rectangular coaxial passive monopulse comparator with integrated antenna array and diode detectors have also been presented. Measured monopulse nulls of 31.4 dB in the ΔAZ plane have been demonstrated. 94-GHz SiGe active monopulse comparator IC and 24 GHz RF-CMOS active monopulse comparator RFIC designs are presented, including detailed simulations of monopulse nulls and performance over frequency. Simulations of the W-band SiGe active monopulse comparator IC indicate potential for wideband operation, with 30 dB monopulse nulls from 75-105 GHz. For the 24-GHz active monopulse comparator IC, simulated monopulse nulls of 71 dB and 68 dB were reported for the azimuthal and elevational sweeps. Measurements of these ICs were unsuccessful due to layout errors and incomplete accounting for parasitics. Simulated results from a series of rectangular coaxial power corporate power combining structures have been presented, and their relative merits discussed. These designs include 2-1 and 4-1 reactive, Wilkinson, and Gysel combiners at V- and W-band. Measured back-to-back results from Gysel combiners at 60 GHz included insertion loss of 0.13 dB per division for a 2-1 combination, and an insertion loss of 0.3 dB and 0.14 dB for "planar" and "direct" 4-1 combinations, respectively. At 94 GHz, a measured insertion loss of 0.1 dB per division has been presented for a 2-1 Gysel combination, using a back-to-back structure. Preliminary designs for a solid-state power amplifier (SSPA) structure have also been presented. Finally, two conceptual monopulse transceivers will be presented, as a vehicle for integrating the various components demonstrated in this dissertation. / Ph. D.