Ieee transactions on antennas and propagation

An efficient, low-loss, low sidelobe, high dynamic range phased-array radar antenna system is disclosed that uses metamaterials, which are manmade composite materials having a negative index of refraction, to create a biconcave lens architecture (instead of the aforementioned biconvex lens) for focusing the microwaves transmitted by the antenna. Accordingly, the sidelobes of the antenna are reduced. Attenuation across microstrip transmission lines may be reduced by using low loss transmission lines that are suspended above a ground plane a predetermined distance in a way such they are not in contact with a solid substrate. By suspending the microstrip transmission lines in this manner, dielectric signal loss is reduced significantly, thus resulting in a less-attenuated signal at its destination.

Phased array metamaterial antenna system

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Advanced Digital Signal Processing And Noise Reduction

Estimation theory with applications to communications and control

Detection of road boundaries and obstacles is essential for autonomous vehicle navigation. In this paper, we propose a road boundary and obstacle detection method using a downward-looking light detection and ranging sensor. This method extracts line segments from the raw data of the sensor in polar coordinates. After that, the line segments are classified into road and obstacle segments. To enhance the classification performance, the estimated roll and pitch angles of the sensor relative to the scanning road surface in the previous time step are then used. The classified road line segments are applied to track the road boundaries, roll, and pitch angles by using an integrated probabilistic data association filter. The proposed method was evaluated with the autonomous vehicle A1, which was the winner of the 2010 Autonomous Vehicle Competition in Korea organized by the Hyundai-Kia automotive group. The proposed method using the estimated roll and pitch angles can detect road boundaries and roadside, as well as road obstacles under various road conditions, including paved and unpaved roads and intersections.

Enhanced Road Boundary and Obstacle Detection Using a Downward-Looking LIDAR Sensor

This paper presents a statistical analysis of the radar detection characteristics of FMCW based automotive radar in the presence of FMCW interference. The characteristics of interference are investigated and compared with Gaussian noise by determining the distribution and probability of detection for different waveform parameters. The majority of cases show that interference in the victim receiver has a low correlation value and a probability density function close to a Gaussian distribution, with some specific cases demonstrating a sinusoidal distribution. The analysis is validated by experimental results for specific case performance in a controlled laboratory environment.

Statistical Analysis of Automotive Radar Interference

This paper considers methods and results on designing a reduced redundancy Multiple-Input, Multiple-Output (MIMO) ultrasonic sensor array to provide high-resolution, short-range sensing in front of a platform, while simultaneously reducing the amount of sensors required even further than a co-located MIMO array. The method proposed maximises the MIMO virtual aperture size rather than the conventional method of finding redundant physical elements to remove. This is done through adopting a Simulated Annealing and Genetic Algorithm for this problem, to optimise placement for a fixed and small number of sensor elements. The resulting array occupies less physical space than a conventional array of the same beamwidth, making it potentially attractive for small, mobile autonomous platforms. Analytical methods and simulation results are presented, and experimentally confirmed at the proof-of-concept level using a custom-built array. The experimental results verify that the proposed technique can reduce the amount of required sensor elements by 35% compared to a conventional MIMO array.

/pdf/design-and-verification-of-reduced-redundancy-ultrasonic-ma7rotdnxy.pdf

Design and Verification of Reduced Redundancy Ultrasonic MIMO Arrays Using Simulated Annealing & Genetic Algorithms

The transfer of the forward scatter concept to passive coherent location systems provides an emerging area of research. This paper investigates aspects of such a system through analysis and discussion of previous dedicated forward scatter radar research, showing that indeed the addition of a forward scatter channel to existing passive systems would enhance the current capabilities.

Forward scatter radar mode for passive coherent location systems

In this paper, we compare the common remote sensing technologies in terms of their application for road surface classification. The presence of surface classification system in a vehicle will increase the safety of driving, especially in adverse weather conditions, as well as when driving offroad. The paper presents an overview of the application of optical, laser, ultrasonic, and microwave sensors for surface classification. From the analysis it follows that sensor data fusion allows obtaining more accurate and reliable results.

Sensors for Automotive Remote Road Surface Classification

Th e development of Forward Scatter Radar (FSR) for use in maritime applications requires a fundamental understanding of the operating environment. Presently, there is insufficiency of published experimental FSR sea clutter data at near zero grazing angle over the sea. Such data is fundamental for the development of FSR systems for maritime applications. Therefore clutter experiments have been undertaken and data has been recorded at frequencies of 7.5 GHz and 24 GHz with static, medium gain antennas for low sea state 1-3 on the Douglas scale. Analysis of forward scatter propagation phenomena is presented, and spectral and statistical analysis of forward scatter clutter is performed. This paper is continuation of previous published work (5- 10) and it presents the results of clutter studies of an FSR. Essentially this type of radar does not have range/angular resolution (3, 5), clutter is picked up from the large surface area illuminated by Tx/Rx antennas. FSR is clutter, rather than noise, limited (11) and therefore, for estimation of FSR performance, the characteristics of sea clutter in the forward scattering direction at near zero grazing angles must be understood. For this reason, intensive measurements have been conducted in sea conditions, over a range of frequencies and radar parameters of the FSR system. The results discussed here are obtained at frequencies of 7.5 GHz and 24 GHz with grazing angles between 0.05° and 0.7° at different FSR system ranges (800-3300m) and sea states 1-3 by Douglas scale (15). Spectral and statistical analysis of the sea clutter data have been made and will be presented in the paper. Sea clutter has been discussed previously in (8-10) where it was shown that the clutter statistics obey mainly Rayleigh distribution while the spectra been demonstrated to be limited from above by 1Hz and the slopes were of 20 - 35 dB per decade. These results are in good agreement with numerical simulation of near-zero grazing angle FS performed in (13) where spectral and statistical properties of clutter were discussed. In this paper distribution of clutter will be considered as a function of antenna beamwidth, polarization and antenna height.

http://ieeexplore.ieee.org/iel7/6975272/6986107/06991220.pdf

Edward Hoare

Papers

Statistical Analysis of Automotive Radar Interference

Design and Verification of Reduced Redundancy Ultrasonic MIMO Arrays Using Simulated Annealing & Genetic Algorithms

Forward scatter radar mode for passive coherent location systems

Sensors for Automotive Remote Road Surface Classification

Radar Parameters Influence on the Clutter in Maritime Forward Scatter Radar