Target shadow profile reconstruction in forward scatter radar

This thesis is dedicated to the matter of imaging (further explained as profile reconstruction) in Forward Scatter Radars (FSR). Firstly, an introduction to radar systems, including forward scatter radar, is made, then an introduction to the scalar theory of diffraction and principles of holography follows. The application of holographic imaging principles in the microwave domain is studied. The practical modelling of forward scatter radar target signals is made, based on the theoretical expectations and approximations outlined. Theoretical background of the imaging in FSR is made, based on previously published work. A novel approach for profile reconstruction is introduced based on the practices of holographic imaging, together with simulated results. Experimental set-ups used in the feasibility proof are described and experimental results are presented for 8 different targets in both a single-node and multistatic configurations. Preliminary accuracy analysis of these reconstructed target profiles is done, outlining practical application issues and domain of accuracy. Quantitative measures of the accuracy of the reconstructed images are defined

High resolution radargrammetry with COSMO-SkyMed, TerraSAR-X and RADARSAT-2 imagery: development and implementation of an image orientation model for Digital Surface Model generation

Digital Surface and Terrain Models (DSM/DTM) have large relevance in several territorial applications, such as topographic mapping, monitoring engineering, geology, security, land planning and management of Earth's resources. The satellite remote sensing data offer the opportunity to have continuous observation of Earth's surface for territorial application, with short acquisition and revisit times. Meeting these requirements, the SAR (Synthetic Aperture Radar) high resolution satellite imagery could offer night-and-day and all-weather functionality (clouds, haze and rain penetration). Two different methods may be used in order to generate DSMs from SAR data: the interferometric and the radargrammetric approaches. The radargrammetry uses only the intensity information of the SAR images and reconstructs the 3D information starting from a couple of images similarly to photogrammetry. Radargrammetric DSM extraction procedure consists of two basic steps: the stereo pair orientation and the image matching for the automatic detection of homologous points. The goal of this work is the definition and the implementation of a geometric model in order to orientate SAR imagery in zero Doppler geometry. The radargrammetric model implemented in SISAR (Software per Immagini Satellitari ad Alta Risoluzione - developed at the Geodesy and Geomatic Division - University of Rome "La Sapienza") is based on the equation of radar target acquisition and zero Doppler focalization Moreover a tool for the SAR Rational Polynomial Coefficients (RPCs) generation has been implemented in SISAR software, similarly to the one already developed for the optical sensors. The possibility to generate SAR RPCs starting from a radargrammetric model sounds of particular interest since, at present, the most part of SAR imagery is not supplied with RPCs, although the RPFs model is available in several commercial software. Only RADARSAT-2 data are supplied with vendors RPCs. To test the effectiveness of the implemented RPCs generation tool and the SISAR radargrammetric orientation model the reference results were computed: the stereo pairs were orientated with the two model. The tests were carried out on several test site using COSMO-SkyMed, TerraSAR-X and RADARSAT-2 data. Moreover, to evaluate the advantages and the different accuracy between the orientation models computed without GCPs and the orientation model with GCPs a Monte Carlo test was computed. At last, to define the real effectiveness of radargrammetric technique for DSM extraction and to compare the radrgrammetric tool implemented in a commercial software PCI-Geomatica v. 2012 and SISAR software, the images acquired on Beauport test site were used for DSM extraction. It is important underline that several test were computed. Part of this tests were carried out under the supervision of Prof. Thierry Toutin at CCRS (Canada Centre of Remote Sensing) where the PCI-Geomatica orientation model was developed, in order to check the better parameters solution to extract radargrammetric DSMs. In conclusion, the results obtained are representative of the geometric potentialities of SAR stereo pairs as regards 3D surface reconstruction

A Review of Ground Target Detection and Classification Techniques in Forward Scattering Radars

This paper presents a review of target detection and classification in forward scattering radar (FSR) which is a special state of bistatic radars, designed to detect and track moving targets in the narrow region along the transmitter-receiver base line. FSR has advantages and incredible features over other types of radar configurations. All previous studies proved that FSR can be used as an alternative system for ground target detection and classification. The radar and FSR fundamentals were addressed and classification algorithms and techniques were debated. On the other hand, the current and future applications and the limitations of FSR were discussed

STRATHcube : the design of a CubeSat for space debris detection using in-orbit passive bistatic radar

There is a growing need to detect, track and catalogue space debris in the congested Low Earth Orbit (LEO) region. A method to detect debris could be to use space-based passive bistatic radar (PBR). The STRATHcube project proposes to launch a CubeSat into LEO as a PBR technology demonstrator where a signal processing algorithm developed at the University of Strathclyde to detect space debris will be tested. The concept involves a radar receiver and antenna on-board a CubeSat orbiting at a low altitude to detect the radio signals transmitted by operational satellites orbiting at higher altitudes. These signals may have been modified by an object orbiting between the operational satellites and the CubeSat and therefore would indicate a piece of debris exists. This paper will present the integration of PBR technology onto a CubeSat as a payload on the STRATHcube mission and discuss the challenges faced due to the limitations of the small platform. The use of a custom-built 3D antenna and an off-the-shelf patch antenna are investigated as design options for the payload. A high-level design for each option was completed to evaluate their capabilities on the size of trackable debris and to determine their mass and power parameters. After an extensive trade-off analysis at a system level, carried out to narrow down the options of the PBR payload on the CubeSat platform, it was determined that the patch antenna option presented the best way of facilitating the experiment onboard the CubeSat due to its small size and mass. The completed design of the STRATHcube mission will enable an in-orbit demonstration of the PBR technology, which if successful, will provide an alternative to conventional ground-based tracking that is cheaper and more available to the space community. This method would then be proven to industry who can use this approach to implement on a larger scale in the future

Forward scatter radar meets satellite : passive sensing of aerial target using satellite communication waveforms

The problem of single-channel reception of global positioning system (GPS) communication waveforms makes passive sensing of aerial target difficult because of forward scatter. This paper proposes a novel aerial target passive sensing method based on linear canonical transformation (LCT) using the forward scattered satellite communication waveforms. The proposed method firstly preprocesses the received signal based on the characteristics of the traditional satellite tracking loop and the forward scattered satellite communication waveforms to effectively suppress the interference of the direct wave through DC removal. Then, the Gaussian noise and multipath interference in the channel are suppressed by applying a rectangular window to its linear canonical domain. Finally, aerial target sensing is performed based on the peak value of signals in the linear canonical transform domain. The characteristic signal is constructed by analyzing the satellite communication waveforms. Combining the linear canonical transform with the matched filter (MF) to estimate the target parameter. Simulation results show that the proposed method can effectively perform the aerial target sensing by using satellite communication waveforms in the forward scatter scenario

Ricerche di Geomatica 2011

Questo volume raccoglie gli articoli che hanno partecipato al Premio AUTeC 2011. Il premio è stato istituito nel 2005. Viene conferito ogni anno ad una tesi di Dottorato giudicata particolarmente significativa sui temi di pertinenza del SSD ICAR/06 (Topografia e Cartografia) nei diversi Dottorati attivi in Italia

Forward scatter radar: innovative configurations and studies

This thesis is dedicated to the study of innovative forward scatter radar (FSR) configurations and techniques. FSR is a specific kind of bistatic radar having bistatic angle equal or close to 180˚. The goal of this PhD project is to investigate techniques and configurations which would improve FSR performance, making it a more appealing system. This thesis proposes an initial radar overview with deep focus on forward scatter capabilities. FSR principles, radar cross section and target signature are widely discussed. Thus, numerous innovative studies done during this PhD project are presented. FSR passive mode, MIMO geometry and moving transmitter/ moving receiver configurations are here investigated for the first time. Numerous experimental campaigns have been undertaken and a big quantity of data has been collected. Comprehensive analyses on measured and simulated results are presented. Moreover, various novel techniques to estimate target motion parameters have been developed and tested on real and simulated data. Results show a good match between measured and estimated kinematic information. Finally, clutter in moving ends FSR is discussed. In fact, the innovative moving ends configuration is affected by Doppler shift and clutter Doppler spread. Thus, it is important to understand how this issue limits the system performance

Aeronautical Engineering. A continuing bibliography with indexes, supplement 156

This bibliography lists 288 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1982

Maritime forward scatter radar: data collection and clutter analysis

This thesis is the result of study into development, experimental testing and clutter analysis in a Forward Scatter Radar (FSR) designed to detect low reflectivity maritime targets at low grazing angles. The concept of such kind of maritime system is presented; its advantages for surveillance applications are described. Scattering of Electromagnetic (EM) Waves over the sea surface at different radar configurations is outlined with the focus made on forward scattering and appropriate sea clutter models. Phenomenology of the signals in FSR is examined and explained. The development of an experimental FSR hardware operating in X- and K- frequency bands for target detection and clutter analysis and its performance are described in details. It follows with the comprehensive analysis on the measured sea clutter which includes study of influence of a large number of parameters of the radar and sea conditions on the clutter spectral and statistical properties. Finally preliminary analysis of radio frequency (RF) target signatures made with the prototype radar is presented

Maritime forward scatter radar

This thesis is dedicated to the study of forward scatter radar (FSR) in the marine environment. FSR is a class of bistatic radar where target detection occurs at very large bistatic angle, close to the radar baseline. It is a rarely studied radar topology and the maritime application is a completely novel area of research. The aim is to develop an easily deployed buoy mounted FSR network, which will provide perimeter protection for maritime assets—this thesis presents the initial stages of investigation. It introduces FSR and compares it to the more common monostatic/bistatic radar topologies, highlighting both benefits and limitations. Phenomenological principles are developed to allow formation of forward scatter signal models and provide deeper understanding of the parameters effecting the operation of an FSR system. Novel FSR hardware has been designed and manufactured and an extensive measurement campaign undertaken. The outcome of this was the creation of the first comprehensive maritime FSR target and clutter signal database—results from which have been shown with preliminary analysis. Alongside experimental work, a sea surface model has been produced in order to estimate the effects of wave blocking in high sea states and assess FSR performance in these conditions