Browsing by Author "Hobbs, S. E."
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Item Open Access Active debris removal mission from LEO with electric and hybrid propulsion(Cranfield University, 2011-12) Sansica, A.; Hobbs, S. E.Debris proliferation in space environment is an impending problem for preserving future missions. Although prevention measures (IADC guidelines, NASA Handbook for Limiting Orbit Debris) with the intent to regulate and limit the space trac are adopted, the necessity to reduce the increasing quantity of space debris leads to the will to conceive and test the effectiveness of active debris removal missions (ADR). ADR missions are devised for controlling the number of large objects, such as launch vehicle orbital stages or derelict spacecraft which no longer serve a useful purpose [1], orbiting in densely populated and commercially interesting areas (Sun-Synchronous Orbit, SSO).Item Open Access Cloud detection over land for the A-long track scanning radiomater using a fuzzy-set methodology(Cranfield University, 2001-01) Smith, R. J.; Hobbs, S. E.; Morris, JoePolitical, environmental, and commercial needs for information on the Earths surface and atmosphere drive the development of improved satellite data products. At visible and thermal wavelengths the quality of these products is dependent on our ability to distinguish between clouds and the underlying surface. Unlike oceans, land surfaces are highly heterogeneous, containing a wide range of materials, some of which exhibit similar spectral properties to cloud, and hence it is much harder to distinguish between the two. ~ This research project, supported by the Along-Track Scanning Radiometer (ATSR) science team at the Rutherford Appleton Laboratory (RAL), addresses the need for improved cloud detection over land surfaces through the development of an unsupervised cloud detection system for global ATSR-2 scenes over land surfaces. The thesis details the development of the first successful un-supervised near-global cloud detection scheme for ATSR-2 scenes over land surfaces. The scheme developed operates on ATSR-2 data using a fuzzy set methodology. The level of membership of the fuzzy sets is determined using aggregated Gaussian distribution functions defined in a knowledge base that has been developed from the International Satellite Cloud Climatology Project (ISCCP) data sets. This is the first cloud detection algorithm that is uniquely customisable to its end users needs. Specifically, this is achieved through the use of fuzzy set theory and set membership grades. This elegant solution to the problem achieves cloud detection as oppose to cloud clearing, and its final output retains all the information computed on possible classifications of image pixels, thus providing the end user with a true representation of the imprecision inherent in the real-world data. A comprehensive quantitative evaluation and inter-comparison of cloud clearing schemes is presented. This showed that with respect to other algorithms (in literature and currently under development at RAL) F-CLOUD is one of the frontrunners in a new generation of cloud detection algorithms over land surfaces. The scheme is highly accurate and has immediate potential applications within the development programme of future ATSR-2/AATSR products at RAL. Using confusion matricies to analyse hardened results yielded a mean classification accuracy of 92.3% (for a total of forty-five scenes analysed against neph-analysis derived cloud masks).Item Open Access Design of a COTS MST distributed Sensor Suite System for planetary surface exploration(Cranfield University, 2005) Andrews, Faye; Hobbs, S. E.; Honstvet, Ian; Lane, RobinThe aim of this project is To bring together current commercially available technology and relevant Microsystems Technology (MST) into a small, standardised spacecraft primary systems architecture, multiple units of which can demonstrate collaboration… Distributed “lab-on-a-chip” sensor networks are a possible option for the surface exploration of both Earth and Mars, and as such have been chosen as a model small spacecraft architecture. This project presents a systems approach to the design of a collection of collaborative MST sensor suites for use in a variety of environments. Based on a set of derived objectives, the main features of the study are: What are the fundamental limits to miniaturisation? What are the hardware issues raised using both standard and MST components? What is the optimum deployment pattern of the network to locate various shaped targets? What are the strategic and economic challenges of MST and the development of a sensor suite network? In general, there are few fundamental physical laws that limit the size of the sensor system. Limits tend to be driven by other factors including user requirements and the external environment. A simple breadboard model of the sensor suite consisting current COTS MST components raised practical issues such as circuit layouts, power requirements and packaging. A grid illustrating features of the Martian surface was created. Various patterns of target and sensor clusters were simulated. Overall, for larger target areas, clusters of sensors produced the best “hit rate”. The overall system utilises both wired and wireless communications methods. The I2C protocol has been investigated for intersuite communications. A link has been made between bacteria pools found on Glaciers (Cryoconites) and the possible conditions for life at the Polar Ice Caps of Mars. The investigation of Arctic Cryoconites has been selected as a representative case study that will incorporate all aspects of the project and demonstrate the system design. A comprehensive mission baseline based on this application has been produced, however the system has been designed to enable its use in a variety of situations whilst requiring only minimal modification to the overall design.Item Open Access End-to-end low cost space missions beyond earth orbit : a case study for the moon(Cranfield University, 2001-01) Jason, S.; Hobbs, S. E.The research project describes the key mission and systems engineering trade-offs involved in the end-to-end design of an orbiting mission to the Moon, using a "Smaller, Faster, Cheaper" mission approach. This approach is extended to enable the design of a new payload - within the management, cost, schedule, and physical constraints - of the low cost lunar orbiter mission. The payload is designed to image the Moon's permanently dark regions that are believed to contain water ice. To determine the best cost reduction management and engineering approach, the principles for reducing space mission cost are examined and planetary missions are assessed in terms of cost and risk drivers. 'Interplanetary' trajectories and attaining orbit around another body are shown to be the major risk areas encountered by traditional planetary missions. In addition to this, programme management is highlighted as an emerging high risk area for smaller, faster cheaper planetary missions. The preliminary mission design, covering lunar transfer, spacecraft and ground station is described. A 400 kg, three-axis stabilised, lunar orbiter, capable of delivering 20 kg of payload into a low lunar polar orbit is designed. The ground segment comprises one (possibly two) low cost ground stations, linked via the Internet. Images, raw data and telemetry can also be accessed via the Internet. The design-to-launch timeframe spans three years and the total mission cost target of $20 Million is met. The spacecraft is compatible with a range of existing lunar payloads, but the prime mission requirement will be to return images of the Moon's permanently dark craters for the first time. In order to design a low cost payload for imaging the Moon's permanently dark regions, the areas likely to contain the water ice are first characterised. The best and worst case lighting conditions for imaging are then calculated for these regions. The amount of light reaching a crater floor is a function of the crater depth-diameter ratio, solar irradiance incidence angle and local topography. The limiting case is shown to be imaging under starlight illumination only, which is modelled and estimated between 5 to 10µW/m2 over the 350 to 900 nm spectral band. These ultra-low light level conditions have led to identification and evaluation of several solutions in terms of both signal-tonoise ratio performance and development within the constraints of the smaller, faster, cheaper programme. This is achieved using a charge coupled device (CCD) camera employing a commercial sensor and optics. Large format Charge Injection Devices and Complimentary Metal Oxide Semiconductors (Active Pixel Devices) were identified as promising emerging technologies. The baseline low light level imager solution is a CCD array operated in Time Delay Integration mode in order to provide optical images from areas within permanent shadow. An intensified CCD offers a back up solution. The research demonstrates that a low cost lunar mission is technically feasible and additionally, that it is possible to meet a specific (if modest) application target through `smaller, faster, cheaper' payload design. It provides an approach that meets key challenges of planetary exploration at very low cost that can potentially be applied to other near Earth targets.Item Open Access Geosynchronous synthetic aperture radar: design and applications(Cranfield University, 2009-10) Bruno, Davide; Hobbs, S. E.Synthetic Aperture Radar (SAR) imaging from geosynchronous orbit has significant potential advantages over conventional low-Earth orbit (LEO) radars, but also challenges to overcome. This thesis investigates both active and passive geosynchronous SAR configurations, presenting their different features and advantages. Following a system design trade-off that involved phase uncertainties, link budget, frequency and integration time, an L band bi-static configuration with 8-hour integration time that reuses the signal from a non-cooperative transmitter has been presented as a suitable solution. Cranfield Space Research Centre looked into this configuration and proposed the GeoSAR concept, an L band bi-static SAR based on the concept by Prati et al. (1998). It flies along a circular ground track orbit, reuses the signal coming from a noncooperative transmitter in GEO and achieves a spatial resolution of about 100 m. The present research contributes to the GeoSAR concept exploring the implications due to the 8-hour integration time and providing insights about its performance and its possible fields of application. Targets such as canopies change their backscattered phase on timescales of seconds due to their motion. On longer time scales, changes in dielectric properties of targets, Earth tides and perturbations in the structure of the atmosphere contribute to generate phase fluctuations in the collected signals. These phenomena bring temporal decorrelation and cause a reduction in SAR coherent integration gain. They have to be compensated for if useful images are to be provided. A SAR azimuth simulator has been developed to study the influence of temporal decorrelation on GeoSAR point spread function. The analysis shows that ionospheric delay is the major source of decorrelation; other effects, such as tropospheric delay and Earth tides, have to be dealt with but appear to be easier to handle. Two different options for GeoSAR interferometry have been discussed. The system is well suited to differential interferometry, due to the short perpendicular baseline induced by the geometry. A GeoSAR has advantages over a Low Earth Orbit (LEO) SAR system to monitor processes with significant variability over daily or shorter timescales (e.g. soil moisture variation). This potential justifies further study of the concept.Item Open Access An investigation of the polarisation dependence of insect radar cross sections at constant aspect(Cranfield University, 1989-03) Aldhous, Anthony C.; Hobbs, S. E.A low cost system for measuring insect radar cross section (RCS) as a function of polarisation orientation when viewed at constant vertical aspect is presented. A low power continuous wave system (frequency 9.4 GHz) was developed which illuminated a target vertically and measured the power reflected back as the target was rotated in the horizontal plane. Data was collected by a microcomputer and stored on floppy disk for later analysis. A standard target was measured before each insect target and software used this data to calibrate the system for each insect target measurement. A 5 parameter mathematical model, based on the scattering matrix, is described. Software was developed to calculate the parameters from collected data using a least squares procedure. Measurements from 54 specimens representing 18 species of commonly available insect are reported. Average RCS’s were similar to the RCS of water spheres of equivalent mass. For small insects, the maximum and minimum RCS occurred when the electric vector (E-vector) was parallel and perpendicular to the body axis respectively. As insect size increased, a subsidiary maximum developed when the E-vector was perpendicular to the body axis, becoming dominant for the largest insects measured. The shapes of the RCS pattern were approximately ‘mirror’ symmetric, except for the RCS curves from S. gregaria, the largest insects measured, which were asymmetrical and sensitive to the position of the large rear legs. It was found that the ratio of maximum RCS to minimum RCS bore no simple relationship to the ratio of body length to abdomen width of the insect, even when adjusted for mass and was not a useful measure of target shape. The implications of this data are discussed and suggestions for further work are presented.Item Open Access Machine vison and scientific imaging for autonomous air vehicles (UAV)(Cranfield University, 2008-09) Jameson, Pierre-Daniel; Cooke, Alastair K.; Hobbs, S. E.This thesis outlines the necessary requirements to determine an Unmanned Aerial Vehicles (UAV’s) pose relative to a lead aircraft or target, thus enabling a UAV to successfully follow a lead aircraft or target. The use of Machine Vision for Autonomous navigation has been investigated and two flight scenarios were chosen for analysis. Firstly, following a manoeuvring lead aircraft, and secondly, maintaining a steady heading behind a target/lead aircraft (as would be required for in-flight refuelling). In addition, the author has performed a literature review of current research in this field which is significantly dominated by eventual military requirements in order to improve UAV endurance. In addition, experimental work towards developing a passive vision based navigation system has been undertaken. It is hoped that after further research and development this will lead to an eventual flight trial using the flight dynamics department’s UAV’s. The experimental work has been performed using both equipment and software already available within the department and furthermore, it has enabled an analysis of the department’s currently available capabilities for passive visual navigation to be undertaken. Key points for further work have been outlined for the future advancement of the visual navigation project.Item Open Access Microcells for metastructures: an application of microSystem technology to distributed space structures(Cranfield University, 2004-05) Lecuyot, Arnaud; Hobbs, S. E.In this thesis, a new concept of space systems called metastructures is studied. Applications are in very large space structures (1 km) that can take many shapes and be reconfigured during operations. This concept is explored by defining it from a systems engineering perspective, characterising the system dynamics and technical baseline, and assessing its interest with respect to proposed missions and to alternatives. Metastructures are defined as assemblies of microcells linked rigidly. Microcells are themselves defined as Nanosatellites with reduced functionalities, and are referenced locally or globally for active position control within the metastructure. Two reference missions are considered, a centimetric interferometer and a Solar concentrator as part of Solar Power systems. The methods used to analyse these missions and achieve the research objectives are based on strategy analysis, standard practices in mission and system design, and a simplified system dynamics simulation implemented in a custom simulator. The analysis of dynamics demonstrates the controllability of such structures, and their ability to maintain and keep shape in most orbits to good accuracy. It also shows that the design of the distributed controller is important. From this, subsystem requirements are derived for the microcells which are studied as highly integrated microsystems. Mass of the microcells is around 500 g, much of which is propellant. The baseline system configuration for reference missions is derived, including costing. For these missions masses are less than a ton, with costs less that 500 Million Euros. Metastructures do not perform well in terms of lifetime given the simplistic controller used. Appropriate research of decentralised controllers may remedy to this, but a weak point of the concept is that of stowing and launching. Finally, a preliminary analysis of the concept with respect to its alternatives tends to show that it is worthy of further investigation.Item Open Access Microcells for metastructures: An application of MicroSystem technology to distributed space structures(Cranfield University, 2004-05) Lecuyot, A; Hobbs, S. E.In this thesis, a new concept of space systems called metastructures is studied. Applications are in very large space structures (1 km) that can take many shapes and be reconfigured during operations. This concept is explored by defining it from a systems engineering perspective, characterising the system dynamics and technical baseline, and assessing its interest with respect to proposed missions and to alternatives. Metastructures are defined as assemblies of microcells linked rigidly. Microcells are themselves defined as Nanosatellites with reduced functionalities, and are referenced locally or globally for active position control within the metastructure. Two reference missions are considered, a centimetric interferometer and a Solar concentrator as part of Solar Power systems. The methods used to analyse these missions and achieve the research objectives are based on strategy analysis, standard practices in mission and system design, and a simplified system dynamics simulation implemented in a custom simulator. The analysis of dynamics demonstrates the controllability of such structures, and their ability to maintain and keep shape in most orbits to good accuracy. It also shows that the design of the distributed controller is important. From this, subsystem requirements are derived for the microcells which are studied as highly integrated microsystems. Mass of the microcells is around 500 g, much of which is propellant. The baseline system configuration for reference missions is derived, including costing. For these missions masses are less than a ton, with costs less that 500 Million Euros. Metastructures do not perform well in terms of lifetime given the simplistic controller used. Appropriate research of decentralised controllers may remedy to this, but a weak point of the concept is that of stowing and launching. Finally, a preliminary analysis of the concept with respect to its alternatives tends to show that it is worthy of further investigation.Item Open Access Odour nuisance from solid wastes: development of a model describing emission, dispersion and reception(Cranfield University, 1999-06) Sarkar, Ujjaini; Hobbs, S. E.Odours emitted from Municipal Solid Waste (MSW) landfills create nuisance in the surrounding environment. The odour comes from the mixture of volatile organic compounds present in the landfill gas, leachate and leachate treatment systems, sewage sludges and waste materials. The research objective is to develop an Odour Impact Model (OIM) to quantify the impact of odour from a landfill on the surrounding communities. The model provides a basis for site planning and odour regulations. A suitable OIM has been developed with special emphasis on quantifying emissions from the source. A micrometeorological model has been developed based on the estimation of footprints of scalar odour concentration measurements in the atmospheric surface layer. A simple experiment has been designed based on this model. The results of this model have been compared with those from the direct emission measurement approach using a portable Lindvall Hood. Major advantages of the indirect micrometeorological approach are the simplicity of the experiment design, and its ability to cover various spatial resolutions. The commercial software MPTER/COMPLEX-I and UK-ADMS have been used to predict the dispersion of odour around two solid waste sites. UK-ADMS uses a better representation of short-range dispersion (considering plume meandering and in-plume fluctuations) and is thus likely to be more accurate close to the source. The two models compare well at distances greater than 500 metres downwind from the source. The perception recorded in the surrounding community has been analysed with four psychophysical models to validate the impacts predicted by the suitable dispersion model. The model based on Weber-Fechner law describes the relationship between odour intensity and odour concentration (ou/m3) very well for the less intense odour samples, while Laffort’s equation expresses a better relationship with more intense odour samples. The main strength of the integrated OIM is its ability to handle the problem of odour nuisance from solid wastes quantitatively. Amongst the major weakness was poor validation due to lack of sufficient data. Successful use of the OIM will require measurements which account for the extreme variations in surface conditions, cover type, waste composition, wasteage and subsidence.Item Open Access Planetary rovers and data fusion(Cranfield University, 2012-05) Masuku, Anthony Dumisani; Hobbs, S. E.This research will investigate the problem of position estimation for planetary rovers. Diverse algorithmic filters are available for collecting input data and transforming that data to useful information for the purpose of position estimation process. The terrain has sandy soil which might cause slipping of the robot, and small stones and pebbles which can affect trajectory. The Kalman Filter, a state estimation algorithm was used for fusing the sensor data to improve the position measurement of the rover. For the rover application the locomotion and errors accumulated by the rover is compensated by the Kalman Filter. The movement of a rover in a rough terrain is challenging especially with limited sensors to tackle the problem. Thus, an initiative was taken to test drive the rover during the field trial and expose the mobile platform to hard ground and soft ground(sand). It was found that the LSV system produced speckle image and values which proved invaluable for further research and for the implementation of data fusion. During the field trial,It was also discovered that in a at hard surface the problem of the steering rover is minimal. However, when the rover was under the influence of soft sand the rover tended to drift away and struggled to navigate. This research introduced the laser speckle velocimetry as an alternative for odometric measurement. LSV data was gathered during the field trial to further simulate under MATLAB, which is a computational/mathematical programming software used for the simulation of the rover trajectory. The wheel encoders came with associated errors during the position measurement process. This was observed during the earlier field trials too. It was also discovered that the Laser Speckle Velocimetry measurement was able to measure accurately the position measurement but at the same time sensitivity of the optics produced noise which needed to be addressed as error problem. Though the rough terrain is found in Mars, this paper is applicable to a terrestrial robot on Earth. There are regions in Earth which have rough terrains and regions which are hard to measure with encoders. This is especially true concerning icy places like Antarctica, Greenland and others. The proposed implementation for the development of the locomotion system is to model a system for the position estimation through the use of simulation and collecting data using the LSV. Two simulations are performed, one is the differential drive of a two wheel robot and the second involves the fusion of the differential drive robot data and the LSV data collected from the rover testbed. The results have been positive. The expected contributions from the research work includes a design of a LSV system to aid the locomotion measurement system. Simulation results show the effect of different sensors and velocity of the robot. The kalman filter improves the position estimation process.Item Open Access Quantification of the effect of wind driven wheat motion on SAR interferometric coherence(Cranfield University, 2000-10) Seynat, Cedric; Hobbs, S. E.This report quantifies the motion of wheat subject to wind and assesses the effect of this motion on the coherence obtained from Synthetic Aperture Radar (SAR) interferometry. Over vegetation, the loss of coherence due to the change in backscatter between two SAR images taken at a different time (temporal decorrelation) is related to the wind induced motion of vegetation elements. The research aims to provide simultaneous in situ measurements of crop motion and wind velocity at canopy height and to use these measurements in a coherence model to determine the quantitatively the parameters which infer temporal decorrelation. The potential of coherence for agricultural applications is assessed. The three-dimensional motion of wheat is measured by a photogrammetry method using two commercially available video cameras. Simultaneously, wind velocity at canopy height is measured by anemometers at a high sampling frequency. Wheat motion and wind velocity data were collected in a field local to Cranfield University in summer 2000. The CD attached to this report contains the wheat motion and wind velocity data. They show that the motion of wheat is correlated with the wind speed, and that wheat plants adjacent to each other move coherently. The coherence model is based on a statistical approach, which represents the total backscatter from vegetation as the phasor addition of a fixed component and one or more components which are weather dependent. The relative contributions of the total backscatter are estimated with the RT2 backscatter intensity model. The motion measurements are used to define the variability of the phase of the weather dependent components in the model. Outputs of the model show that a C-band SAR with an incidence angle of 23° (typical configuration of the ERS satellites) yields coherence values highly variable with the wind conditions at the time of the radar passes. The potential use of coherence for agricultural applications is limited by this variability, which infers the need for an accurate coherent backscatter model.Item Open Access SAR remote sensing of soil Moisture(Cranfield University, 2014-12) Snapir, Boris; Hobbs, S. E.Synthetic Aperture Radar (SAR) has been identified as a good candidate to provide high-resolution soil moisture information over extended areas. SAR data could be used as observations within a global Data Assimilation (DA) approach to benefit applications such as hydrology and agriculture. Prior to developing an operational DA system, one must tackle the following challenges of soil moisture estimation with SAR: (1) the dependency of the measured radar signal on both soil moisture and soil surface roughness which leads to an ill-conditioned inverse problem, and (2) the difficulty in characterizing spatially/temporally surface roughness of natural soils and its scattering contribution. The objectives of this project are (1) to develop a roughness measurement method to improve the spatial/temporal characterization of soil surface roughness, and (2) to investigate to what extent the inverse problem can be solved by combining multipolarization, multi-incidence, and/or multi-frequency radar measurements. The first objective is achieved with a measurement method based on Structure from Motion (SfM). It is tailored to monitor natural surface roughness changes which have often been assumed negligible although without evidence. The measurement method is flexible, a.ordable, straightforward and generates Digital Elevation Models (DEMs) for a SAR-pixel-size plot with mm accuracy. A new processing method based on band-filtering of the DEM and its 2D Power Spectral Density (PSD) is proposed to compute the classical roughness parameters. Time series of DEMs show that non-negligible changes in surface roughness can happen within two months at scales relevant for microwave scattering. The second objective is achieved using maximum likelihood fitting of the Oh backscattering model to (1) full-polarimetric Radarsat-2 data and (2) simulated multi-polarization / multi-incidence / multi-frequency radar data. Model fitting with the Radarsat-2 images leads to poor soil moisture retrieval which is related to inaccuracy of the Oh model. Model fitting with the simulated data quantifies the amount of multilooking for di.erent combinations of measurements needed to mitigate the critical e.ect of speckle on soil moisture uncertainty. Results also suggest that dual-polarization measurements at L- and C-bands are a promising combination to achieve the observation requirements of soil moisture. In conclusion, the SfM method along with the recommended processing techniques are good candidates to improve the characterization of surface roughness. A combination of multi-polarization and multi-frequency radar measurements appears to be a robust basis for a future Data Assimilation system for global soil moisture monitoring.Item Open Access Satellite formation flying for an interferometry mission(Cranfield University, 2005-10) Roberts, Jennifer A.; Hobbs, S. E.The autonomous formation flying of multiple spacecraft to replace a single large satellite will be an enabling technology for many future missions. In this research, the current status of formation flying missions and technologies is determined, and the Darwin nulling interferometry mission, which aims to detect and characterise extrasolar planets, is selected as the research focus. Darwin requires high precision formation flying of multiple telescopes near the Sun-Earth L2 point. A comprehensive account of current research in astrobiology is presented which provides the motivation for a Darwin-type mission. Astrobiology is integral to the definition of formation manoeuvres and target identification. The system design issues associated with developing a higher resolution, Planet Imager mission are also explored through a preliminary mission design. Relative dynamics models for satellite formation flying control in Low Earth Orbit (LEO) and L2 are developed and methods of incorporating the Earth oblateness perturbation (J2) into the equations of relative motion to improve model fidelity are investigated. The linearised J2 effect is included in the Hill equations in time averaged and time varying form. The models are verified against the Satellite Tool Kit (STK) numerical orbit propagator, and applied to optimal control system design and evaluation for formation keeping tasks. The ‘reference orbit’ modelling approach applied in LEO is applied to the development of a new formation flying model at L2. In this case, linearised equations of motion of the mirror satellites relative to the hub are derived and performance evaluated for different initial conditions. These and other higher order models are compared to STK. The linearised model is applied to controller design for station keeping and formation manoeuvring tasks suitable for a Darwin-type mission, and the role of the model in developing controllers for a load levelling guidance system is explored.Item Open Access Synthetic aperture radar remote sensing for landfill monitoring(Cranfield University, 2007-05) Ottavianelli, Giuseppe; Hobbs, S. E.; Smith, RichardDespite today’s intensive efforts directed at the recycling and recovery of solid wastes, the controlled disposal of refuse into land remains an important and necessary means of effective waste management. The work presented in this thesis investigates the use of Synthetic Aperture Radar (SAR) data to monitor solid waste landfills. The end-users’ interests vary from detecting the presence of a landfill to more specifically monitoring on-site operations and environmental conditions. Following a general literature review on the application of Earth Observation data for landfill monitoring, the identified research objectives are to: 1) assess whether SAR data can support the identification of landfill sites by distinguishing them from other disturbed areas which present similar optical spectral signatures, and 2) assess the possibility of correlating SAR data with onsite operational procedures. Data acquired for the research are: ground observations and measurements examining the spatial, temporal and biophysical characteristics of a landfill that can influence SAR data; historical and new programmed SAR scenes obtained from the ESA ERS-1 and -2 satellites and from Envisat ASAR instrument; ground based SAR (GB-SAR) acquisitions; simulations based on the RT2 backscatter model; additional space-based and airborne optical data to support the analysis and discussion. The examination of both the SAR amplitude spatial structure and the temporal decorrelation of these sites shows that there are three key characteristics that can distinguish them from other disturbed areas with similar optical spectral signatures: the presence of anisotropic features that strongly affect the SAR backscatter; the fact that the coherence magnitude images of these sites are characterised by large decorrelated areas with transient attributes; and their distinctive positive topography. The analysis highlights that one single-polarisation acquisition can hardly provide correct land-cover information, and consequently knowledge on land-use. The research demonstrates the key value of merging together complementary information derived from both the space and time dimensions, achieving fairly accurate land-use classification results. The research also provides an appreciation of the applicability of the developed techniques in an operational framework. These can suffer a number of limitations if a landfill site is located in a particular environment, and/or if meteorological conditions can significantly affect the radar signal, and/or unusual landfilling procedures are applied by the operators. Concluding remarks on the end-users needs point out that there are a number of aspects, ranging from practical and managerial matters to legal and technical issues, that often discourage the utilisation of EO data by new potential users.