Vehicular traffic surveillance and road lane detection using radar interferometry

Speed enforcement on public roadways is an important issue in order to guarantee road security and to reduce the number and seriousness of traffic accidents. Traditionally, this task has been partially solved using radar and/or laser technologies and, more recently, using video-camera based systems. All these systems have significant shortcomings that have yet to be overcome. The main drawback of classical Doppler radar technology is that the velocity measurement fails when several vehicles are in the radars beam. Modern radar systems are able to measure speed and range between vehicle and radar. However, this is not enough to discriminate the lane where the vehicle is driving on. The limitation of several vehicles in the beam is overcome using laser technology. However, laser systems have another important limitation: They cannot measure the speed of several vehicles simultaneously. Novel video-camera systems, based on license plate identification, solve the previous drawbacks, but they have the problem that they can only measure average speed but never top-speed. This paper studies the feasibility of using an interferometric linear frequency modulated continuous wave radar to improve top-speed enforcement on roadways. Two different systems based on down-the-road and across-the-road radar configurations are presented. The main advantage of the proposed solutions is they can simultaneously measure speed, range, and lane of several vehicles, allowing the univocal identification of the offenders. A detailed analysis about the operation and accuracy of these solutions is reported. In addition, the feasibility of the proposed techniques has been demonstrated with simulations and real experiments using a Ka-band interferometric radar developed by our research group.

Desarrollo de Técnicas Interferométricas para Radares de Alta Resolución en Milimétricas

En esta tesis doctoral se aborda el desarrollo de técnicas interferométricas para radares de alta resolución en milimétricas. Específicamente, se centra en el desarrollo de técnicas para radares terrestres y en concreto aquellas relacionadas con el seguimiento, clasificación y generación de imágenes de blancos móviles. Aparte del desarrollo teórico y simulación de las diferentes técnicas, uno de los grandes retos de esta tesis es la verificación experimental de las mismas. Para este propósito, se empleará un prototipo de sensor radar interferométrico de muy alta resolución y de ondas milimétricas. El primer capítulo de la tesis realiza una pequeña introducción a las técnicas interferométricas y presenta los objetivos, motivación y organización del presente trabajo. El segundo capítulo hace una pequeña introducción a los radares interferométricos de alta resolución en milimétricas y presenta el sensor radar experimental con el que se llevarán a cabo la validación de las distintas técnicas presentadas. El tercer capítulo recoge las distintas técnicas interferométricas desarrolladas para el seguimiento y cálculo de la altura de blancos móviles en radares de alta resolución. Entre ellas se encuentran: el seguimiento de blancos móviles en sucesión de imágenes ISAR, el cálculo de altura de blancos en imágenes radar bidimensionales distancia-tiempo y su equivalente en imágenes distancia-Doppler. El cuarto capítulo presenta una aplicación de las técnicas interferométricas para la vigilancia de tráfico en carreteras. Se describirán dos configuraciones radar que permiten calcular la velocidad de todos los blancos iluminados por el radar identificando de manera unívoca a los blancos en función del carril por el que circulen. El quinto capítulo presenta técnicas interferométricas aplicadas a la vigilancia en entornos marítimos basadas en la generación de imágenes interferométricas. Para demostrar la viabilidad del uso de estas imágenes se ha desarrollado un simulador de blancos móviles extensos realistas. Abstract This Ph. D thesis deals with the development of radar interferometry techniques for high-resolution millimeter wave sensors. It focuses on the development of techniques for ground-based radars and specifically those related to monitoring, classification and imaging of moving targets. Apart from the theoretical development and simulation, another major technical challenge of this thesis is the experimental verification of the different techniques. For that purpuse, a very high resolution interferometric millimeter wave radar sensor is used. The first chapter of the thesis makes a brief introduction to the interferometric techniques and shows the goals, motivation and organization of this work. The second chapter provides a brief introduction to high resolution interferometric radars in millimeter waves and presents the experimental radar sensor which will be used for the validation of the various techniques presented. The third chapter presents the different interferometric techniques developed for monitoring and obtaining the height of moving targets in high resolution radars. Among them are: tracking of moving targets in a succession of ISAR images, targets height calculation using bidimensional range-time radar images and the equivalente technique using range-Doppler images. The fourth chapter presents the application of interferometric techniques for road traffic monitoring. Two radar configurations are described. Both of them are able to obtain the speed for simultaneuslly illuminated targets, and univocally identify each target based on the detected road lane. The fifth chapter presents the application of interferometric techniques to maritime surveillance based on interferometric imaging. To demonstrate the feasibility of the presented techniques a realistic simulator of extended moving targets has been developed.

Ice volume estimates from ground-penetrating radar surveys, Wedel Jarlsberg Land glaciers, Svalbard

One of the aims of the SvalGlac project is to obtain an improved estimate, with reliable error estimates, of the volume of Svalbard glaciers and their potential contribution to sea level rise. As part of this work, we present volume calculations, with detailed error estimates, for eight glaciers on Wedel Jarlsberg Land, southern Spitsbergen, Svalbard. The volume estimates are based upon a dense net of GPR-retrieved ice thickness data collected over several field campaigns spanning the period 2004-2011. The total area and volume of the ensemble are 502.9±18.6 km2 and 80.72±2.85 km3, respectively. Excluding Ariebreen (a tiny glacier, menor que 0.4 km2 in area), the individual areas, volumes and average ice thickness lie within 4.7-141.0 km2, 0.30-25.85 km3 and 64-183 m, respectively. The maximum recorded ice thickness, ca. 619±13 m, is found in Austre Torellbreen. To estimate the ice volume of small non-echo-sounded tributary glaciers, we used a function providing the best fit to the ice thickness along the centre line of a collection of such tributaries where echo-soundings were available, and assuming parabolic cross-sections. We did some tests on the effect on the measured ice volumes of the distinct radio-wave velocity (RWV) of firn as compared to ice, and cold versus temperate ice, concluding that the changes in volume implied by such corrections were within the error bounds of our volume estimate using a constant RWV for the entire glacier inferred from common mid-point measurements on the upper ablation area.

Ice volume estimates from ground-penetrating radar surveys, Wedel Jarlsberg Land glaciers, Svalbard

We present ground-penetrating radar (GPR)—based volume calculations, with associated error estimates, for eight glaciers on Wedel Jarlsberg Land, southwestern Spitsbergen, Svalbard, and compare them with those obtained from volume-area scaling relationships. The volume estimates are based upon GPR ice-thickness data collected during the period 2004–2013. The total area and volume of the ensemble are 502.91 ± 18.60 km2 and 91.91 ± 3.12 km3, respectively. The individual areas, volumes, and average ice thickness lie within 0.37–140.99 km2, 0.01–31.98 km3, and 28–227 m, respectively, with a maximum recorded ice thickness of 619 ± 13 m on Austre Torellbreen. To estimate the ice volume of unsurveyed tributary glaciers, we combine polynomial cross-sections with a function providing the best fit to the measured ice thickness along the center line of a collection of 22 surveyed tributaries. For the time-to-depth conversion of GPR data, we test the use of a glacierwide constant radio-wave velocity chosen on the basis of local or regional common midpoint measurements, versus the use of distinct velocities for the firn, cold ice, and temperate ice layers, concluding that the corresponding volume calculations agree with each other within their error bounds.