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Gps-Denied Navigation Using Synthetic Aperture Radar, Tucker Hathaway

All Graduate Theses and Dissertations, Fall 2023 to Present

In most modern navigation systems, GPS is used to determine the precise location of the vehicle; however, GPS signals can easily be blocked, jammed, or spoofed. These signals can be blocked by canyons or tall buildings. Additionally, adversaries can transmit signals that either make GPS signals difficult to interpret or that imitate real GPS signals and cause a navigation system to think it is somewhere other than its true location. GPS-denied (GPS-D) navigation is the process of navigating in the absence of GPS.

Many methods of performing GPS-D navigation have been proposed and explored. One such method is to use …

An 8-Bit Analog-To-Digital Converter For Battery Operated Wireless Sensor Nodes, Marvin Wayne Suggs Jr.

Graduate Theses and Dissertations

Wireless sensing networks (WSNs) collect analog information transduced into the form of a voltage or current. This data is typically converted into a digital representation of the value and transmitted wirelessly using various modulation techniques. As the available power and size is limited for wireless sensor nodes in many applications, a medium resolution Analog-to-Digital Converter (ADC) is proposed to convert a sensed voltage with moderate speeds to lower power consumption. Specifications also include a rail-to-rail input range and minimized errors associated with offset, gain, differential nonlinearity, and integral nonlinearity. To achieve these specifications, an 8-bit successive approximation register ADC is …

Computational_Electromagnetic Modeling (Cem) Of Foliage Penetration (Fopen), Monica R. Jaramillo

Electrical and Computer Engineering ETDs

Foliage penetration (FOPEN) radar at lower frequencies (UHF, VHF) is a well-studied area with a wide set of contributions. However, there is growing interest in using higher Ku-band frequencies (12-18 GHz frequency range) for FOPEN. In particular, the reduced wavelength sizes (centimeters range) provide some key saliencies for developing more optimized foliage detection solutions. The disadvantage is that exploiting Ku-band for FOPEN is complicated because higher frequencies have much more pronounced scattering effects due to their smaller wavelengths. Despite these challenges, certain foliage characteristics and signal parameters can help improve electromagnetic (EM) wave penetration in the Ku-band such as foliage …

Cmos Design Of An 8-Bit 1ms/S Successive Approximation Register Adc, Ameya Vivekanand Ganguli

Master's Theses

Rapid evolution of integrated circuit technologies has paved a way to develop smaller and energy efficient biomedical devices which has put stringent requirements on data acquisition systems. These implantable devices are compact and have a very small footprint. Once implanted these devices need to rely on non-rechargeable batteries to sustain a life span of up to 10 years. Analog-to-digital converters (ADCs) are key components in these power limited systems. Therefore, development of ADCs with medium resolution (8-10 bits) and sampling rate (1 MHz) have been of great importance.

This thesis presents an 8-bit successive approximation register (SAR) ADC incorporating an …

Insar Simulations For Swot And Dual Frequency Processing For Topographic Measurements, Gerard Masalias Huguet

Masters Theses

In Earth remote sensing precise characterization of the backscatter coefficient is important to extract valuable information about the observed target. A system that eliminates platform motion during near-nadir airborne observations is presented in this thesis, showing an improvement on the accuracy of measurements for a Ka- band scatterometer previously developed at Microwave Remote Sensing Laboratory (MIRSL). These very same results are used to simulate the reflectivity of such targets as seen from a spaceborne radar and estimate height errors based on mission-specific geometry. Finally, data collected from a dual-frequency airborne interferometer com- prised by the Ka-band system and an S-band …

Analysis Of Human Emf Exposure In 5g Cellular Systems, Imtiaz Nasim

Electronic Theses and Dissertations

Increasing concerns of communications at a frequency spectrum higher than 6 GHz have gained international alarm that suggests more research is needed before it is deployed successfully. In this context, in the first part of this thesis, we investigated the human electromagnetic field (EMF) exposure in indoor and outdoor environments from fifth-generation (5G) downlink communications and compared its impacts with the present cellular technologies considering the features that the 5G will likely adopt. The second part focuses on mitigation of human exposure for both indoor and outdoor environments with two different methods adopted. Our simulation results suggest that while the …

Microwave Detection Of Surface Breaking Cracks In Metallic Structures Under Heavy Corrosion And Paint, John Robert Gallion

Masters Theses

"We live in the world of "aging infrastructures". In this environment, critical and heavily utilized infrastructure, i.e. ships, planes, bridges, etc., are operating at or beyond their designed age. Replacement is no longer an option and "retirement for cause" is the current approach to maintenance and replacement. Consequently, there is an ever-increasing demand for efficient and robust nondestructive evaluation (NDE) methods that can determine the physical health of these structures. Large structures, which are primarily made of metals, either steel or aluminum, are susceptible to high-stress cracking and corrosion. Stress-induced cracks in heavily corroded steel, used in bridges, railroads, storage …

Leveraging 3d Models For Sar-Based Navigation In Gps-Denied Environments, Zachary A. Reid

Browse all Theses and Dissertations

This thesis considers the use of synthetic aperture radar (SAR) to provide absolute platform position information in scenarios where GPS signals may be degraded, jammed, or spoofed. Two algorithms are presented, and both leverage known 3D ground structure in an area of interest, e.g. provided by LIDAR data, to provide georeferenced position information to airborne SAR platforms. The first approach is based on the wide-aperture layover properties of elevated reflectors, while the second approach is based on correlating backprojected imagery with digital elevation imagery. Both of these approaches constitute the system we have designated: SARNAV. Building on 3D backprojection, localization …

Impact Of Near-Field-To-Far-Field Transformation On Sar Images Formed In An Indoor Non-Anechoic Environment, Jacob D. Compaleo

Browse all Theses and Dissertations

This work investigates the impact of the near-field-to-far-field transformation (NFFFT) algorithm on phase history measurement collections completed in the Sensors and Signals Exploitation Laboratory (SSEL). SSEL is an indoor non-anechoic environ- ment that is at risk to some measurement interferences such as multiple bounces. Complete 360-degree phase history measurements of scale model aircraft are con- ducted at varying range values within the near-field limit. These measurements are calibrated with the Mie series scattering solution for a sphere. After calibration, the measurements are transformed using the NFFFT, with radar cross-section (RCS) estimated. RCS of the transformed data is compared with the …

Design And Simulation Of An 8-Bit Successive Approximation Register Charge-Redistribution Analog-To-Digital Converter, Sumit K. Verma

Electrical Engineering Theses

The thesis initially investigates the history of the monolithic ADCs. The next chapter explores the different types of ADCs available in the market today. Next, the operation of a 4-bit SAR ADC has been studied. Based on this analysis, an 8-bit charge-redistribution SAR ADC has been designed and simulated with Multisim (National Instruments, Austin, TX). The design is divided into different blocks which are individually implemented and tested. Level-1 SPICE MOSFET models representative of 5μm devices were used wherever individual MOSFETs were used in the design. Finally, the power dissipation during the conversion period was also estimated. The supply voltage …

Kasi: A Ka-Band And S-Band Cross-Track Interferometer, Gerard Ruiz Carregal

Masters Theses

A dual-frequency system is needed to better understand natural processes that constitute the environment and seasonal cycles of the Earth. A system working at two different wavelengths acquiring data simultaneously will give a valuable dataset since the conditions on the ground will be exactly the same. Hence, elements such as wind, soil moisture or any other changes on the ground will not interfere in the mea- surements. This thesis explains how an S-band radar was built and tested. Moreover, the experiments done with a Ka-band radar used as a scatterometer are explained as well as the data processing and analysis. …

Effects Of The Kinematic Model On Forward-Model Based Spotlight Sar Ecm, David T. Pyles

Browse all Theses and Dissertations

Spotlight synthetic aperture radar (SAR) provides a high-resolution remote image formation capability for airborne platforms. SAR image formation processes exploit the amplitude, time, and frequency shifts that occur in the transmitted waveform due to electromagnetic propagation and scattering. These shifts are predictable through the SAR forward model which is dependent on the waveform parameters and emitter flight path. The approach to develop an electronic countermeasure (ECM) system that is founded on the SAR forward model implies that the ECM system should alter the radar's waveform in a manner that produces the same amplitude, time, and frequency shifts that a real …

Scaled Synthetic Aperture Rader Development, Jason Garvey Schray

Master's Theses

Several previous Cal Poly thesis projects involve synthetic aperture radar (SAR), automatic target recognition (ATR), and tracking. SAR data was either accessed from a publicly available database or generated using complex computer modeling software. The motivation for this dual thesis project is to design and construct a scaled SAR system to support Cal Poly radar projects. Ideally this is a low-cost, high resolution SAR architecture that produces raw range Doppler data for any desired target area. To that end, a scaled SAR system was successfully designed, built, and tested. The current SAR system, however, does not perform azimuthal compression and …

Scaled Synthetic Aperture Radar System Development, Ryan K. Green

Master's Theses

Synthetic Aperture Radar (SAR) systems generate two dimensional images of a target area using RF energy as opposed to light waves used by cameras. When cloud cover or other optical obstructions prevent camera imaging over a target area, SAR can be substituted to generate high resolution images. Linear frequency modulated signals are transmitted and received while a moving imaging platform traverses a target area to develop high resolution images through modern digital signal processing (DSP) techniques. The motivation for this joint thesis project is to design and construct a scaled SAR system to support Cal Poly radar projects. Objectives include …

Synthetic Aperture Radar: Rapid Detection Of Target Motion In Matlab, Daniel S. Kassen

Master's Theses

Synthetic Aperture Radar (SAR) has come into widespread use in several civilian and military applications. The focus of this paper is the military application of imaging point targets captured by an airborne SAR platform. Using the traditional SAR method of determining target motion by analyzing the difference between subsequent images takes a relatively large amount of processing resources. Using methods in this thesis, target motion can be estimated before even a single image is obtained, reducing the amount of time and power used by a significantly large amount. This thesis builds on work done by Brain Zaharri and David So. …

Uav Navigation And Radar Odometry, Eric Blaine Quist

Theses and Dissertations

Prior to the wide deployment of robotic systems, they must be able to navigate autonomously. These systems cannot rely on good weather or daytime navigation and they must also be able to navigate in unknown environments. All of this must take place without human interaction. A majority of modern autonomous systems rely on GPS for position estimation. While GPS solutions are readily available, GPS is often lost and may even be jammed. To this end, a significant amount of research has focused on GPS-denied navigation. Many GPS-denied solutions rely on known environmental features for navigation. Others use vision sensors, which …

Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham

Theses and Dissertations

Opportunities to use synthetic aperture radar (SAR) in scientific studies and military operations are expanding with the development of small SAR systems that can be operated on small unmanned air vehicles (UAV)s. While the nimble nature of small UAVs make them an attractive platform for many reasons, small UAVs are also more prone to deviate from a linear course due autopilot errors and external forces such as turbulence and wind. Thus, motion compensation and improved processing algorithms are required to properly focus the SAR images. The work of this dissertation overcomes some of the challenges and addresses some of the …

Monostatic Airborne Synthetic Aperture Radar Using Commercial Wimax Transceivers In The License-Exempt Spectrum, Kai Liu

Electronic Thesis and Dissertation Repository

The past half-century witnessed an evolution of synthetic aperture radar (SAR). Boosted by digital signal processing (DSP), a variety of SAR imaging algorithms have been developed, in which the wavenumber domain algorithm is mature for airborne SAR and independent of signal waveforms. Apart from the algorithm development, there is a growing interest in how to acquire the raw data of targets’ echoes before the DSP for SAR imaging in a cost-effective way. For the data acquisition, various studies over the past 15 years have shed light on utilizing the signal generated from the ubiquitous broadband wireless technology – orthogonal frequency …

Recursive-Ransac: A Novel Algorithm For Tracking Multiple Targets In Clutter, Peter C. Niedfeldt

Theses and Dissertations

Multiple target tracking (MTT) is the process of identifying the number of targets present in a surveillance region and the state estimates, or track, of each target. MTT remains a challenging problem due to the NP-hard data association step, where unlabeled measurements are identified as either a measurement of an existing target, a new target, or a spurious measurement called clutter. Existing techniques suffer from at least one of the following drawbacks: divergence in clutter, underlying assumptions on the number of targets, high computational complexity, time-consuming implementation, poor performance at low detection rates, and/or poor track continuity. Our goal is …

Low Voltage Cmos Sar Adc Design, Ryan Hunt

Electrical Engineering

This project centers on the design of a single ended 10-bit successive approximation register analog to digital converter (SAR ADC for short) that easily interfaces to a micro-controller, such as an Arduino. With micro-controller interfacing in mind, the universal data transfer technique of SPI proved an easy way to communicate between the ADC and the micro-controller. The ADC has a range of 1V (highest code value) to 0V (lowest code value) and operates from a single voltage rail value of 1.8V. Typical SPI clock speeds run on the order of 2MHz and with a 10-bit ADC this means a sampling …

Applications Of Artificial Neural Networks To Synthetic Aperture Radar For Feature Extraction In Noisy Environments, David James Roberts

Master's Theses

It is often that images generated from Synthetic Aperture Radar (SAR) are noisy, distorted, or incomplete pictures of a target or target region. As the goal for most SAR research pertains to automatic target recognition (ATR), extensive filtering and image processing is required in order to extract the features necessary to carry out ATR. This thesis investigates the use of Artificial Neural Networks (ANNs) in order to improve upon the feature extraction process by laying the foundation for ANN SAR ATR algorithms and programs. The first technique investigated is that of an ANN edge detector designed to be invariant to …

Synthetic Aperture Radar Rapid Detection Of Range And Azimuth Velocities Implemented In Matlab, Cheuk Yu David So

Master's Theses

The Synthetic Aperture Radar (SAR) algorithm processes multiple radar returns from the target space to generate a single high-resolution image. Targets moving through the target space during the capture sequence will appear distorted on the final image. In addition, there is no velocity information that is calculated as part of the processing. The objective of this thesis is to develop techniques to determine the azimuth and range velocities of moving objects in the target space in the early stages of SAR processing. The typical SAR processing steps are Range Compressed, Range Doppler, and final image generation. The range velocity of …

An Investigation Into Ground Moving Target Indication (Gmti) Using A Single-Channel Synthetic Aperture Radar (Sar), Joseph W. Winkler

Theses and Dissertations

Synthetic aperture radar (SAR) was originally designed as an airborne ground-imaging radar technology. But it has long been desired to also be able to use SAR imaging systems to detect, locate, and track moving ground targets, a process called Ground Moving Target Indication (GMTI). Unfortunately, due to the nature of how SAR works, it is inherently poorly suited to the task of GMTI. SAR only focuses targets and image features that remain stationary during the data collection. A moving ground target therefore does not focus in a conventional SAR image, which complicates the process of performing GMTI with SAR systems. …

Uhf-Sar And Lidar Complementary Sensor Fusion For Unexploded Buried Munitions Detection, Randy S. Depoy Jr.

Browse all Theses and Dissertations

Given the UHF bands properties of foliage and round penetration, a UHF-SAR image contains both above- and below-surface scatterers. The problem of detecting sub-surface objects is problematic due to the presence of above-surface scatterers in the detection images. In case of a single-pass anomaly image or a two-pass change image, the resulting anomalies or changes are due to scatterers above and below the surface, where the above surface anomalies/changes act as confusers. LIDAR digital elevation models (DEM) provide georegistered information about the above-surface objects present in the UHF-SAR scene. Detection of the above-surface objects in the LIDAR domain is used …

Extension Of Polar Format Scene Size Limits To Squinted Geometries, Matthew Steven Horvath

Browse all Theses and Dissertations

The Polar Format Algorithm (PFA) is an often used algorithm to image synthetic aperture radar (SAR) phase history data. The algorithm relies on a far-field approximation wherein the curved wavefront of the transmitted pulses is approximated as a planar wavefront, introducing spatially variant phase errors in the phase history. While allowing for faster image formation compared to more exact imaging algorithms such as convolution backprojection, these phase errors lead to the distortion and defocus of point targets, degrading the quality of the resulting imaged scene.

Historically, a Taylor expansion has been used to approximate the phase errors leading to distortion …

Sar Map Of Gel Phantom In A 64mhz Mri Birdcage By Fiber-Optic Thermometry And Fdtd Simulation, Chirag Mukesh Patel

Master's Theses

As implantable medical devices are being used more often to treat medical problems for which pharmaceuticals don’t suffice, it is important to understand their interactions with commonly used medical modalities. The interactions between medical implants and Magnetic Resonance Imaging machines have proven to be a risk for patients with implants.

Implanted medical devices with elongated metallic components can create harmful levels of local heating in a Magnetic Resonance Imaging (MRI) environment [1]. The heating of a biological medium under MRI is monitored via the Specific Absorption Rate (SAR). SAR, defined as power absorbed per unit mass (W/kg), can be calculated …

High Resolution Simulation Of Synthetic Aperture Radar Imaging, Cindy G. Romero

Master's Theses

The goal of this Master’s thesis is to develop a more realistic simulation of Synthetic Aperture Radar (SAR) that has the ability to image detailed targets, and that can be used for Automatic Target Recognition (ATR). This thesis project is part of ongoing SAR ATR research at California Polytechnic State University (Cal Poly) sponsored by Raytheon Space & Airborne Systems and supervised by Dr. John Saghri.

SAR is a form of radar that takes advantage of the forward motion of an antenna mounted on a moving platform (such as an airplane or spacecraft) to synthetically produce the effect of a …

Multi-Aperture Coherent Change Detection And Interferometry For Synthetic Aperture Radar, David D. Madsen

Theses and Dissertations

Interferometry and coherent change detection (CCD) utilize phase differences between complex SAR images to find terrain height and to detect small changes between images, respectively. A new method for improving interferometry and CCD using multiple sub-apertures is proposed. Using backprojection processing, multiple sub-aperture images are created for a pair of flights. An interferogram and coherence map is made from each sub-aperture. For CCD, each sub-aperture coherence map offers an independent estimate of the coherence over the same area. By combining coherence maps, low coherence areas associated with residual motion errors are reduced, shadowed areas are minimized, and the overall coherence …

Low Cost/ High Precision Flight Dynamics Estimation Using The Square-Root Unscented Kalman Filter, Trevor H. Paulsen

Theses and Dissertations

For over a decade, Brigham Young University's Microwave Earth Remote Sensing (MERS) team has been developing SAR systems and SAR processing algorithms. In order to create the most accurate image reconstruction algorithms, detailed aircraft motion data is essential. In 2008, the MERS team purchased a costly inertial measurement unit (IMU) coupled with a high precision global positioning system (GPS) from NovAtel, Inc. In order to lower the cost of obtaining detailed motion measurements, the MERS group decided to build a system that mimics the capability the NovAtel system as closely as possible for a much lower cost. As a first …

Synthetic Aperture Radar Imaging Simulated In Matlab, Matthew Schlutz

Master's Theses

This thesis further develops a method from ongoing thesis projects with the goal of generating images using synthetic aperture radar (SAR) simulations coded in MATLAB. The project is supervised by Dr. John Saghri and sponsored by Raytheon Space and Airborne Systems. SAR is a type of imaging radar in which the relative movement of the antenna with respect to the target is utilized. Through the simultaneous processing of the radar reflections over the movement of the antenna via the range Doppler algorithm (RDA), the superior resolution of a theoretical wider antenna, termed synthetic aperture, is obtained. The long term goal …