The Fundamentals of Radar with Applications to Autonomous Vehicles

Radar systems can be extremely useful for applications in autonomous vehicles. This paper seeks to show how radar systems function and how they can apply to improve autonomous vehicles. First, the basics of radar systems are presented to introduce the basic terminology involved with radar. Then, the topic of phased arrays is presented because of their application to autonomous vehicles. The topic of digital signal processing is also discussed because of its importance for all modern radar systems. Finally, examples of radar systems based on the presented knowledge are discussed to illustrate the effectiveness of radar systems in autonomous vehicles

A Low Cost Remote Sensing System Using PC and Stereo Equipment

A system using a personal computer, speaker, and a microphone is used to detect objects, and make crude measurements using a carrier modulated by a pseudorandom noise (PN) code. This system can be constructed using a personal computer and audio equipment commonly found in the laboratory or at home, or more sophisticated equipment that can be purchased at reasonable cost. We demonstrate its value as an instructional tool for teaching concepts of remote sensing and digital signal processing.Comment: Accepted for publication in American Journal of Physic

Millimeter-wave Communication and Radar Sensing — Opportunities, Challenges, and Solutions

With the development of communication and radar sensing technology, people are able to seek for a more convenient life and better experiences. The fifth generation (5G) mobile network provides high speed communication and internet services with a data rate up to several gigabit per second (Gbps). In addition, 5G offers great opportunities of emerging applications, for example, manufacture automation with the help of precise wireless sensing. For future communication and sensing systems, increasing capacity and accuracy is desired, which can be realized at millimeter-wave spectrum from 30 GHz to 300 GHz with several tens of GHz available bandwidth. Wavelength reduces at higher frequency, this implies more compact transceivers and antennas, and high sensing accuracy and imaging resolution. Challenges arise with these application opportunities when it comes to realizing prototype or demonstrators in practice. This thesis proposes some of the solutions addressing such challenges in a laboratory environment.High data rate millimeter-wave transmission experiments have been demonstrated with the help of advanced instrumentations. These demonstrations show the potential of transceiver chipsets. On the other hand, the real-time communication demonstrations are limited to either low modulation order signals or low symbol rate transmissions. The reason for that is the lack of commercially available high-speed analog-to-digital converters (ADCs); therefore, conventional digital synchronization methods are difficult to implement in real-time systems at very high data rates. In this thesis, two synchronous baseband receivers are proposed with carrier recovery subsystems which only require low-speed ADCs [A][B].Besides synchronization, high-frequency signal generation is also a challenge in millimeter-wave communications. The frequency divider is a critical component of a millimeter-wave frequency synthesizer. Having both wide locking range and high working frequencies is a challenge. In this thesis, a tunable delay gated ring oscillator topology is proposed for dual-mode operation and bandwidth extension [C]. Millimeter-wave radar offers advantages for high accuracy sensing. Traditional millimeter-wave radar with frequency-modulated continuous-wave (FMCW), or continuous-wave (CW), all have their disadvantages. Typically, the FMCW radar cannot share the spectrum with other FMCW radars.\ua0 With limited bandwidth, the number of FMCW radars that could coexist in the same area is limited. CW radars have a limited ambiguous distance of a wavelength. In this thesis, a phase-modulated radar with micrometer accuracy is presented [D]. It is applicable in a multi-radar scenario without occupying more bandwidth, and its ambiguous distance is also much larger than the CW radar. Orthogonal frequency-division multiplexing (OFDM) radar has similar properties. However, its traditional fast calculation method, fast Fourier transform (FFT), limits its measurement accuracy. In this thesis, an accuracy enhancement technique is introduced to increase the measurement accuracy up to the micrometer level [E]

Non-contact Vital Signs Monitor

An apparatus for measuring simultaneous physiological parameters such as heart rate and respiration without physically connecting electrodes or other sensors to the body. A beam of frequency modulated continuous wave radio frequency energy is directed towards the body of a subject. The reflected signal contains phase information representing the movement of the surface of the body, from which respiration and heartbeat information can be obtained. The reflected phase modulated energy is received and demodulated by the apparatus using synchronous quadrature detection. The quadrature signals so obtained are then signal processed to obtain the heartbeat and respiratory information of interest.Georgia Tech Research Corporatio

Development and application of spread-spectrum ultrasonic evaluation technique

A new approach to ultrasonic NDE called spread-spectrum ultrasonic evaluation (SSUE) is investigated. It regards the ultrasonic nondestructive evaluation as an acoustic-impulse-response estimation and characterization problem. This problem has been compared with the analogous problems of radio-detection-and-ranging from communications field and the seismic exploration problem of geophysics. Out of the various options for the impulse response estimation, the continuous pseudorandom signal correlation method has been shown to be the optimum for peak-power limited systems such as the ultrasonic NDE systems. The problem of self-noise and its consequences in pseudorandom correlation systems is investigated, followed by the development of various optimum and sub-optimum approaches to self-noise elimination. After verifying the theoretical results through computer simulations, a lab-grade SSUE instrument was developed and analyzed. Also, a new, efficient method for the implementation of DSP-based correlator is developed. The application of SSUE technique to various practical NDE situations like, flaw detection, velocity/thickness measurements, attenuation measurement, global integrity assessment, etc., was investigated through various laboratory experiments. It is concluded that the SSUE technique holds great promise for all ultrasonic NDE applications where high signal attenuation results into the loss of signal-to-noise ratios beyond workable limits;SSUE employs a non-traditional approach to ultrasonic NDE that makes it more robust and powerful. One significant feature of the SSUE technique is that it overcomes the maximum average power limitation of the existing techniques. Conventional pulsed ultrasonic NDE systems are peak power limited by the transducer breakdown voltage and the average power is limited by the narrow pulse duration which is important to maintain good resolution. In certain NDE applications there are factors other than the transducer peak power limitation, which limit the amplitude of the transmitted signal. In case of medical ultrasound devices, for example, the peak power limit arises from the risk of causing tissue damage. For such kind of applications, SSUE has a direct solution to increasing the average power while maintaining the resolution. Ultrasonic NDE instrument in a field or industrial environment is subject to all kinds of acoustic and electromagnetic interferences. This results into a degradation of instrument sensitivity and reliability. SSUE technique, by virtue of its robust operating principal, is capable of interference rejection to a much larger extent

AGV RAD: AGV positioning system for ports using microwave doppler radar

Automation and intelligence have become an inevitable trend in the development of container terminals. The AGV (Automated Guided Vehicle) positioning is a primary problem to build the automated ports. Although the existing Ultra-High Frequency(UHF) RFID technology has good measurement accuracy and stability in the port AGV positioning, the exposed magnetic tags are easy to damage under the common heavy load, and its construction and maintenance cost is unbearable to most ports. Among the candidate technologies for the AGV positioning, microwave Doppler radar has a strong penetrating ability, and can work well in a complex environment (day and night, foggy, rainy). Therefore, the microwave Doppler radar-based AGV positioning system has attracted a lot of attention. In this thesis, a test system using the above technique was established, together with a NI myRIO real-time Wi-Fi compatible computation platform. Several computation algorithms were implemented to extract the accurate values of range and velocity. Wavelet denoising with the adapted threshold function was considered to filter noise contained in radar signals. In the frequency domain analysis, FFT and Chirp-Z Transform (CZT) joint algorithm was proposed to suppress the influence of fence effects and also improves real-time performance. In addition, 2D-FFT is used to calculate velocity of AGV. According to the port-like environment, the suitable AGV positioning algorithm and communication method based on microwave Doppler radars and NI myRIO-1900s also be proposed. The effectiveness of the proposed system was experimentally tested and several results are included in this thesis.Automação e inteligência artifical tornaram-se uma tendência inevitável no desenvolvimento dos terminais dos contentores. O posicionamento do VAG (Veículo Autónomo Guiado) é um dos problemas principais para construir as portas automatizadas. Embora a tecnologia RFID de frequência ultra-alta (UHF) existente tenha uma boa precisão e estabilidade de medição no posicionamento VAG dos portos, as etiquetas magnéticas expostas são fáceis de danificar sob a comum carga pesada e o seu habitual custo de construção e manutenção é insuportável para a maioria das portos. Entre as tecnologias para o posicionamento VAG, o radar Doppler de microondas possui uma forte capacidade de penetração e pode funcionar bem em ambientes complexos (dia, noite, nevoeiro e chuva). Portanto, o sistema de posicionamento VAG baseado em radar Doppler de microondas atraiu muita atenção. Nesta tese, foi estabelecido um sistema de teste usando a técnica acima mencionada, juntamente com uma plataforma de computação em tempo real, NI myRIO compatível com Wi-Fi. Vários algoritmos de computação foram envolvidos para extrair os valores precisos de distancia e velocidade. O “denoising” de wavelets com a função de limiar adaptado foi utilizado para filtrar o ruído nos sinais de radar. Na análise do domínio da frequência, o algoritmo conjunto FFT e Chirp-Z Transform (CZT) foi proposto para suprimir a influência dos efeitos de resolução e também melhorar o desempenho em tempo real. Além disso, o algoritmo 2D-FFT é usado para calcular a velocidade do VAG. De acordo com o ambiente dos portos, o algoritmo de posicionamento VAG e o método de comunicação adequado baseados em radares Doppler de microondas e NI myRIO-1900s também serão propostos. A eficiência do sistema proposto foi testada experimentalmente e vários resultados estão descritos nesta dissertação

The Development of an Independent Frequency Modulated Continuous Wave Radar for Perimeter Security

The accessibility of Frequency Modulated Continuous Wave (FMCW) radars has provided several diverse industries with a microwave sensor that can be utilized reliably for many different applications. The research specified in this thesis focuses primarily on the perimeter security industry with the application of detecting human targets through the use of FMCW radar. The foundational efforts that this research entails is the development of an FMCW radar where every component of the radar will eventually end up as independently user designed. The purpose of achieving the independent hardware design is pave the way for further hardware and software improvements without being hampered by the currently cumbersome and limited hardware setup. The achievement of an independent setup will open a lot more options to modifying and improving the FMCW radar. As of now, the FMCW radar setup is composed of pre-built hardware that was purchased and constructed together in the Microwaves Lab. Using this purchased hardware, an algorithm is made to process the data in order to create a full functional FMCW radar. The experiments relating to the algorithm is presented and documented as a troubleshooting guide. Once the algorithm is completed, alternative pre-built hardware is used as an indicator for the algorithm’s capability with other hardware. This information will validate the compatibility of the algorithm for the hardware that is going to be designed in the Microwaves Lab. Once the several experiments with the algorithm are completed, an approach to the independent design of the FMCW radar will be introduced. In this thesis, this approach will introduce the antenna design portion of the FMCW radar. The antenna design is primarily focusing on factors that would contribute to human detection. The preliminary simulation of the antenna is intended to be developed further upon until a fabrication of the antenna is achieved. Once a fully capable FMCW radar can be realized for each component of the setup, significant improvements can be achieved on the radar setup. These improvements can be: improving the number of targets that can be tracked simultaneously (as related to the antenna design), minimizing the physical size of the hardware (which is the result of transitioning the code from MATLAB to C++), and experimenting this completed setup with other hardware to potentially extend the range of the radar without increasing the power (from the usage of the reflectarray attachment). Some of these future works can extend the application of FMCW radars to other industries outside of perimeter security