Azimuth

GPS multipath reflectometry (GPS-MR) is a technique that uses geodetic quality GPS receivers to estimate snow depth. The accuracy and precision of GPS-MR retrievals are evaluated at three different sites: grasslands, alpine, and forested. The assessment yields a correlation of 0.98 and an rms error of 6-8 cm for observed snow depths of up to 2.5 m. GPS-MR underestimates in situ snow depth by 10%-15% at these three sites, although the validation methods do not measure the same footprint as GPS-MR.

In this paper, we propose an approach to the problem of simultaneous shape and refractive index recovery from multispectral polarisation imagery captured from a single viewpoint. The focus of this paper is on dielectric surfaces which diffusely polarise light transmitted from the dielectric body into the air. The diffuse polarisation of the reflection process is modelled using a Transmitted Radiance Sinusoid curve and the Fresnel transmission theory. We provide a method of estimating the azimuth angle of surface ...

We examine the improvement attained by using acoustic vector sensors for direction-of-arrival (DOA) estimation, instead of traditional pressure sensors, via optimal performance bounds and particular estimators. By examining the Cramér-Rao bound in the case of a single source, we show that a vectorsensor array's smaller estimation error is a result of two distinct phenomena: 1) an effective increase in signal-to-noise ratio due to a greater number of measurements of phase delays between sensors and 2) direct measurement of the DOA information contained in the structure of the velocity field due to the vector sensors' directional sensitivity. Separate analysis of these two phenomena allows us to determine the array size, array shape, and SNR conditions under which the use of a vector-sensor array is most advantageous and to quantify that advantage. By extending the beamforming and Capon direction estimators to vector sensors, we find that the vector sensors' directional sensitivity removes all bearing ambiguities. In particular, even simple structures such as linear arrays can determine both azimuth and elevation, and spatially undersampled regularly spaced arrays may be employed to increase aperture and, hence, performance. Large sample approximations to the mean-square error matrices of the estimators are derived and their validity is assessed by Monte Carlo simulation.

The structure and operating principles of a solar compass conceived and realised at the ENEA Laboratories in Frascati are presented. The optical design, the underlying software and the calibration procedure make this instrument a reliable, stand-alone tool with an unprecedented combination of accuracy and cost-effectiveness. In-field operation gives evidence of azimuth determination capability with an accuracy of 0.01°. Exploitation of built-in sensors of smartphones (e.g. GPS, camera, accelerometer) allowed us to move this technology to popular level, providing everybody with a cheap tool of orienteering, far superior to any magnetic compass, despite a reduced accuracy with respect to the original instrument.

Fusion of radar and EO-sensors for the purpose of surveillance is investigated. All sensors are considered to be co-located with respect to the distance of the area under surveillance. More specifically, the applicability for such multi-sensor systems is examined for surveillance in littoral waters. The sensor suite is a coherent polarimetric radar in combination with a set of camera's sensitive in visible light, near infrared, mid infrared and far infrared. A so-called fuse while track algorithm is the best candidate for these dissimilar colocated and not necessarily synchronized sensors.

Based on EuroNCAP regulations the number of autonomous emergency braking systems for pedestrians (AEB-P) will increase over the next years. According to accident research a considerable amount of severe pedestrian accidents happen at artificial lighting, twilight or total darkness conditions. Because radar sensors are very robust in these situations, they will play an important role for future AEB-P systems. To assess and evaluate systems a pedestrian dummy with reflection characteristics as close as possible to real humans is indispensable. As an extension to existing measurements in literature this paper addresses open issues like the influence of different positions of the limbs or different clothing for both relevant automotive frequency bands. Additionally suggestions and requirements for specification of pedestrian dummies based on results of RCS measurements of humans and first experimental developed dummies are given.

Presso i Laboratori del Centro Ricerche ENEA di Frascati sono stati realizzati diversi prototipi di bussola solare compatta e in grado di fornire la direzione del Nord geografico in qualunque luogo del pianeta con elevata accuratezza (0.01°).
Inizialmente progettata per impianti solari a concentrazione, la bussola solare ENEA è applicabile a qualsiasi strumento di rilevamento, come teodoliti, stazioni totali, laser scanner, ecc.  Il suo basso costo, piccolo ingombro ed il completo automatismo elettronico rendono questo dispositivo uno strumento accessibile e di facile impiego per qualsiasi utilizzatore, sia a livello professionale che amatoriale.
In particolare, essa può essere utilizzata in archeoastronomia laddove la tipica precisione delle bussole magnetiche risulti insufficiente, specialmente in un periodo come questo che vede un deciso aumento dello spostamento casuale del Polo Nord magnetico.
Oltre allo strumento professionale, presentiamo anche una App in grado di trasformare qualsiasi telefono di tipo smartphone in una precisa bussola solare.

This work, illustrates the development of 2 GHz Low Noise Amplifier (LNA) interfaced with square truncated edge-fed
right circularly polarized patch antenna. The LNA is simulated on Agilent ADS platform with TSMC 130nm RF CMOS
process. The development of cascode amplifier and its optimization has been further exemplified. The developed LNA is
tuned for 2 GHz and the performance is tuned for high stability factor of 4, Gain of 19 dB which is essential for any
mobile device, Noise Figure (NF) of 1.15 dB with a P1dB point at -9 dBm. Further a truncated patch antenna with
right circular polarization has been simulated on EMpro. The antenna has a gain of 6.1 dB in the azimuth plane. The
simulated system can be further integrated to form the RF front end of TDD2000 LTE standard mobile device.

This paper presents a review of tilt angle and azimuth angles in solar energy applications. The paper involves an overview of design parameter, applications, simulations and mathematical techniques covering different usage application. The number of references analysing the tilt angle deployment in the context of the research papers of the different countries currently having operations in solar systems is much more significant. Different kinds of models and test methods of optimum tilt angle in different solar systems have been developed since 1956 which can be distinguished by their particular mathematical models or tracking techniques as shown in the latest researches. The mathematical models allows the calculation of different parameters of the solar radiation, the angle of inclination, and the optimum tilt angle of the collecting surface and the effects acting on the system.

The technique of interpolated arrays is applied to ESPRIT-type direction finding methods. The resulting method uses sensor arrays with an arbitrary configuration, thus eliminating the basic restrictive requirement of ESPRIT for two (or more) identical arrays. This approach allows for resolving D+1, while the original ESPRIT method requires at least 2D sensors. Moreover, it is shown that while ESPRIT performs poorly for signals propagating in parallel (or close to parallel) with the array displacement vector, the advocated technique does not exhibit such weakness. Finally, using two subarrays, ESPRIT cannot resolve azimuth and elevation even when the sensors are not collinear. However, the interpolated ESPRIT procedure resolves azimuth and elevation using only a single array. The performance of the original ESPRIT when the sensor locations are perturbed is also discussed and illustrated numerically

Radar position estimation from target signals suffers from main-beam jamming. One way to counteract the problem is to integrate data from multiple sensors. An adaptive monopulse Multiple Signal Classification (MUSIC) algorithm discerns the azimuth and elevation angle estimation or true spectrum amongst jamming, but relying solely on the algorithm results in an undesirable position location and navigation error. By integrating

If several closely spaced targets fall within the same radar beam and between two adjacent matched filter samples in range, monopulse information from both of these samples can and should be used for estimation, both of angle and of range (i.e., estimation of the range to sub-bin accuracy). Similarly, if several closely spaced targets fall within the same radar beam and among three matched filter samples in range, monopulse information from all of these samples should be used for the estimation of the angles and ranges of these targets. Here, a model is established, and a maximum likelihood (ML) extractor is developed. The limits of the number of targets that can be estimated are given for both case A, where the targets are in a beam and in a range "slot" between the centers of two adjacent resolution cells (that is, from detections in two adjacent matched filter samples), and case B, where the targets are in two or more adjacent slots (among three or more adjacent samples). A minimum description length (MDL) criterion is used to detect the number of targets between the matched filter samples, and simulations support the theory.

T.L. Cicciarella, Monocromo. Appunti per un regesto.
Pubblicato in: S. Troisi (a cura di), Monocromo. L’utopia del colore. p. 118-127. Silvana Editoriale, Cinisello Balsamo 2009. ISBN: 9788836614639

Catalogo della mostra “Monocromo. L’utopia del colore”, a cura di Sergio Troisi. Marsala, Convento del Carmine, maggio-ottobre 2009.

The invention of smart grid has already outdated the conventional method of one way power production- supply concept. While developed countries have already started to adopt smart meters, appliances and renewable energy sources; underdeveloped and developing countries are still facing power shortages every day. In the second Industrial Revolution, electricity was the main advancement and the recent Industrial Revolution 4.0 has pushed giant Production companies into the adoption and promotion of Renewable Energy sources. The integration of IoT and power systems has revolutionized the world in terms of power efficiency and real time monitoring. This paper discusses an experimental work done on how IoT can monitor the power/voltage and current production of a standalone renewable energy source i.e. a solar panel. This paper also discusses how to improve the solar panel efficiency by correcting the tilt angle of the solar panel. The monitoring of the solar panel is done via an inter-connected system using NodeMCU, Node-RED, Arduino and an MQTT channel. The monitoring of solar panels can be made easier by implementing the proposed work in a photovoltaic (PV) power plant. Moreover the monitoring of energy production will greatly enhance the health of the PV system. A 24% increase in the power output has been noticed after the correction of the tilt angle which was corrected using a solar tracker.

KEYWORDS
IoT based Solar Panel, Solar monitoring, NodeMCU, Node-RED, MQTT, Tilt Correction using IoT, Azimuth Correction using IoT.

This paper introduces a novel eigenstructure-based algorithm uni-vector-sensor ESPRIT that yields closed-form direction-of-arrival (DOA) estimates and polarization estimates using one electromagnetic vector sensor. A vector sensor is composed of six spatially co-located nonisotropic polarizationsensitive antennas, measuring all six electromagnetic field components of the incident wave field. Uni-vector-sensor ESPRIT is based on a matrix-pencil pair of temporally displaced data sets collected from a single electromagnetic vector sensor. The closed-form parameter estimates are obtained through a vector cross-product operation on each decoupled signalsubspace eigenvector of the data correlation matrix. This method exploits the electromagnetic sources' polarization diversity in addition to their spatial diversity, requires no a priori knowledge of signal frequencies, suffers no frequency-DOA ambiguity, pairs automatically the x-axis direction cosines with the y-axis direction cosines, eliminates array interelement calibration, can resolve up to five completely polarized uncorrelated monochromatic sources from near field or far field. It impressively out-performs an array of spatially displaced identically polarized antennas of comparable array-manifold size and computational load.

An interactive software tool, here called Spatial Analysis of Lineaments (SAL), has been developed for calculating the spatial properties azimuth, length, spacing, and unidirectional frequency of lineaments which are defined by their start and end coordinates. In a series of steps the user is guided by displays of relevant statistical distributions, which can be user designed. Statistical outliers can be excluded and the total sample of lineaments can be subdivided into azimuth sets and, if required, into spatial clusters. Special attention is given to the removal of spatial outliers in an interactive way. Several rule-based decisions are made to determine the nearest lineament in the spacing calculation. As a default procedure, the program defines a window whose size depends on the mode value of the length distribution of the lineaments in the study area. The software can accept a large amount of lineaments and can analyze the spatial properties of each azimuth set avoiding the repetitive calling of the original database. A simple rule was developed to derive the unidirectional lineament frequency. The spatial properties are presented as histograms for each azimuth set together with the mode, mean, standard deviation, and number of involved lineaments.

L'ENEA ha sviluppato una bussola solare in grado di funzionare nelle missioni spaziali per navigare tra i pianeti. Questo strumento può essere adattato ad applicazioni terrestri, in particolare, per la navigazione su mezzi mobili come navi ed aerei, su mezzi speciali attrezzati per rilevamenti ambientali e mezzi privi di autista.
L'ENEA è aperta a collaborazioni con altri Enti di ricerca o con imprese per sviluppare una bussola 'marziana' o una bussola per mezzi mobili terrestri.

The objective of this paper is to investigate and explain how binaural audio uses psychoacoustics in order to create effects which virtually position sound sources anywhere in three-dimensional space. To do this, a short summary on psychoacoustics will be made. Moreover, different parameters of 3D audio will be reviewed in order to understand its link with the aforementioned discipline. Different sources will be studied to achieve this objective.

Distance-Based Amplitude Panning (DBAP) has recently been proposed as a new technique for panning sound sources in two and three dimensional spaces spaces. In this paper, DBAP is compared with two established alternatives, Ambisonics and Vector-Based Amplitude Panning, both objectively in terms of speaker gains and their variation with source position, and subjectively using listening tests to estimate apparent source position.

This paper addresses several innovative steps needed in the chirp scaling and extended chirp scaling (ECS) algorithms in order to process staring Spotlight TerraSAR-X (TSX) images with 21 cm azimuth resolution and 300 MHz range bandwidth. The aspects that need of special consideration are the 2D phase truncation in frequency domain of ECS, the element pattern of the antenna array, the curved orbit, the stop-and-go approximation, and the troposphere. All these aspects are expounded in detail and a solution is given for each of them. The suggested corrections are applied at raw data level, hence easing the integration within the existing TSX processor. Real data acquired by TSX in the experimental staring Spotlight mode are used to validate the proposed methodology.

to the early days of spacebane Synthetic Aperture Radar ( S A R ) is known as the minimum antenna area constraint for S A R . In this paper, it is confmed that this constraint strictly applies only to the case where both the best possible resolution and the widest possible swath are the design goals. S A R antennas with area smaller than the constraint allows are shown to be possible, have been used on spaceborne S A R missions in the past, ad should permit further, lowercost SAR missions in the future.

A shaped-beam reflectarray based on patches, aperture-coupled to delay lines is demonstrated for local multipoint distribution system (LMDS) central station antennas, in the 10.10-10.70 GHz band. The antenna must cover a 60°-sector in azimuth with a squared cosecant pattern in elevation. The design process consists of two steps. First, a phase-only pattern synthesis technique is applied to obtain the required phase-shift distribution on the reflectarray surface which generates the shaped pattern. The second stage consists of determining the length of the delay lines, aperture-coupled to the square patches, in order to achieve the phase distribution synthesized in the previous step. Two reflectarray antennas have been designed, one for vertical (V) and the other for horizontal (H) polarization. A breadboard for V-polarization has been manufactured and tested in an anechoic chamber, showing a good agreement between theoretical and measured radiation patterns. Jose A. Encinar (S'

The paper describes the simulation results for a ground penetrating SAR radar. As a simulation model of SAR system the pulse radar with LFM (Linear Frequency Modulation) signal has been applied. The aim of the experiment was to test ability of the SAR system to obtain fully focused image of the underground targets. Simulation results presented in the paper are

Bistatic synthetic aperture radars (BSARs) have been the focus of increasing research activity over the last decade. The generalized ambiguity function (GAF) of bistatic SAR is introduced here. First, the GAF for BSAR is represented in the delay-Doppler domain, and is then expanded to the spatial (coordinates) domain. From the GAF, comprehensive knowledge regarding the resolution of BSAR can be extracted, including the range and azimuth resolutions, as well as the area of a resolution cell of BSAR. These general results are also applied to the performance analysis of several particular BSAR geometries, including the space-surface-BSAR (SS-BSAR) system, to demonstrate the potential ability of this newly introduced system.

The conventional matched filter approach uses the replica of thc transmitted, frequency modulated signal to generate a reference function for the range compression. Phase and amplitude errors occuring in the total transceiver chain before digitalization will be contained in the reference function, which is the complex conjugate of the time reversed replica. The impulse response function in this case has the best achievable signal to noise ratio but high sidelobes or paired echoes will appear for severe phase and amplitude errors. We present here a new method for the generation of the reference function from the replica, which provides both, matched filtering and deconvolution of the amplitude and phase errors. The final impulse response function will be like the ideal one irrespective of the amount of errors present. Several simulation results are shown which are significant for the improvement of the image quality and for relaxation in the amount of allowed amplitude and phase errors in the S A R design for range processing. The proposed method can also be extended to azimuth processing of signals received a t high squint angles.

The navigation and mobile positioning paradigm has been an active research topic in the past two decades. The proliferation of mobile devices equipped with inertial sensors able to detect phone motion lead to an increase in research and product development in the field of personal locating technologies. Within this scenario, this paper proposes a combined technique for the estimation of user's position in indoor environments, which only relies on sensors of a commercial smartphone, without the active aid of external infrastructures. The smartphone's video camera is used to identify known keypoints, named anchors previously identified and geo-referenced in the building map. A SURF algorithm is employed for quick and effective detection of image features independently from the viewpoint. The accelerometers and the compass of the smartphone are used to estimate the amount of steps and the direction in which the user is moving by performing statistical data processing. Heading data is compensated taking into account the relative position of the smartphone with respect to the user. Experiments have been carried out in a real scenario showing the effectiveness of the proposed solutions.

Radar space-time adaptive processing (STAP) techniques have classically focused on azimuth-Doppler adaptivity while placing minimal emphasis on elevation. Elevation adaptivity offers significant clutter suppression improvement, allowing further suppression of interference sources having identical Doppler and azimuth as the expected target. Work is presented which incorporates elevation adaptivity using two approaches: a factored approach and a joint domain approach, both greatly improving clutter suppression performance. The proposed concepts are validated using results based on simulated range ambiguous airborne radar data. Target detection improvements on the order of 8 dB :and 10 dB (as compared to standard 2D-JDL processing) are demonstrated for the factored and joint domain approaches, respectively, using an 8 x 8 nonuniform rectangular array.

A software tool is presented which calculates the spatial properties azimuth, length, spacing, and frequency of lineaments that are defined by their starting and ending co-ordinates in a two-dimensional (2-D) planar co-ordinate system. A simple graphical interface with five display windows creates a user-friendly interactive environment. All lineaments are considered in the calculations, and no secondary sampling grid is needed for the elaboration of the spatial properties. Several rulebased decisions are made to determine the nearest lineament in the spacing calculation. As a default procedure, the programme defines a window that depends on the mode value of the length distribution of the lineaments in a study area. This makes the results more consistent, compared to the manual method of spacing calculation. Histograms are provided to illustrate and elaborate the distribution of the azimuth, length and spacing. The core of the tool is the spacing calculation between neighbouring parallel lineaments, which gives direct information about the variation of block sizes in a given category of structures. The 2-D lineament frequency is calculated for the actual area that is occupied by the lineaments. r

With the increasing development of national rocket and missile technology as conducted by LAPAN and PINDAD, as well as the need to control/monitor UAV navigation for various purposes, it is therefore the time for the development of ground station with automatic tracking ability. This research is a continuation of one year research conducted earlier on the implementation of automatic tracking platform to maintain continuous communication channel between ground station and moving objects such as rocket/UAV and research on the RX-420 rocket antenna conducted with LAPAN. In the second year, a tracking system has been implemented with microstrip-array based antenna multiband 900 MHz/2.4 GHz/S-band to support rocket/UAV tracking and telemetry communication, rocket/UAV control command and video transmission simultaneously. The tracking distance was also increased to 100 km. Moreover, in the second year of research, tracking algorithm is also improved to support multi-object tracking at greater distance of > 100 km.

MEMPHIS is an experimental millimeter-wave synthetic aperture radar (SAR) system that acquires cross-track multibaseline interferometric data at high resolution in a single pass, using four receive horns. In this paper, we present the SAR system and navigation data, and propose a processing chain from the raw data input to a digital surface model (DSM) output. This processing chain includes full bandwidth reconstruction of the steppedfrequency SAR data, azimuth focusing with an Extended Omega-K algorithm, generation of interferograms for each available baseline, phase unwrapping using the multibaseline data, and phaseto-height conversion. The hardware and processing chain were validated through the analysis of experimental Ka-band data. The SAR image resolution was measured with point targets and found to be and coarser than the theoretical value in range and azimuth, respectively. The geolocation accuracy was typically better than 0.1 m in range and 0.2 m in azimuth. Observed depression angledependent interferometric phase errors were successfully removed using a correction function derived from the InSAR data. Investigation of the interferometric phase noise showed the utility of a multibaseline antenna setup; the number of looks and filter size used for the DSM generation were also derived from this analysis. The results showed that in grassland areas, the height difference between the-resolution InSAR DSMs and the reference ALS models was .

This paper presents a new algorithm for deconvolution of low resolution non-coherent radar images. The technique presented, is based on an LMS iterative approach, but has important modifications to accommodate the constraints imposed by the absence of phase information in the radar return. The algorithm also operates at a higher resolution than the sample points, in order to compensate for the lack of range and azimuth resolution. This new technique is compared to standard iterative algorithms in both the time and frequency domains. Simulated radar data is used to demonstrate the benefits of the algorithm.

1 --Recently, Wu et al. proposed a scheme for two-dimensional (2-D) direction of arrival angle estimation (DOA) for azimuth and elevation angles, using the propagator method (PM). An advantage of this method over the classical subspace based algorithms, such as ESPRIT and MUSIC, is that it does not apply any eigenvalue decomposition (EVD) to the cross spectral matrix or singular value decomposition (SVD) to the received data. This significantly reduces the computational complexity, compared to the EVD and SVD. However, Wu's method has some drawbacks such as pair matching between the azimuth and elevation angle estimations for multiple different sources. And furthermore, Wu's method has an estimation failure problem in the range of practical mobile elevation angles. The objective of this paper is to overcome these two problems with less arithmetic operation counts than Wu used, and to improve the performance significantly. To achieve these objectives, we propose an antenna array configuration which avoids these problems. Simulation results verify that the proposed scheme can remove these problems and give much better performance.

— This paper primarily concerns with the determination of life of bracket assembly of Azimuth Thruster under fatigue and structural considerations. An Azimuth thruster is an arrangement of marine propellers placed in pods which can be rotated to any horizontal angle (azimuth). Joseph Becker, invented the Z-drive azimuth propeller first in 1950, whereas this kind of propulsion was first patented by Pleuger in 1955. The ships fitted with this system give better maneuverability than a fixed propeller and rudder system. As thrust acts on the assembly, the well is supported by structures like brackets, struts etc. After brief research on the optimization of design of propellers, performances, there is a scope of improvisation in the design of supporting structures related to the assembly. In this paper, problems while assembling the structure are discussed. In order to mitigate these problems, its expected life under working conditions is found out. Also, structural analysis is carried out to compare as-designed and as-fitted assembly under given thrust loading conditions.

In this paper, random switch antenna array (RSAA) is proposed to apply to the switch antenna array (SAA) frequency-modulated continuous-wave (FMCW) radar system. Firstly, the signal model and signal processing method of RSAA is analyzed and it shows that RSAA can successfully solve azimuthvelocity coupling problem. Then we suppose a method by using RSAA to reduce the switching frequency and sampling rate based on sparse signal representation with multiple measurement vectors (MMV). It is shown in simulations that the proposed algorithms yield better performance in terms of azimuth-velocity decoupling and can obtain high image accuracy with less observation data.

Majority of ROVs are underwater vehicles with relatively slow dynamics virtually providing a ROV pilot extra time to perform other tasks, such as inspections and arm operation. However, with many tasks performed simultaneously with flying, the relevant information is typically dispersed on a number of screens overloading the pilot's visual channel. Surprisingly, there is very little research examining the unique human-factors problems associated with unmanned underwater vehicles. Use of audio display has been suggested as a means to reduce visual workload, to enhance situation awareness, and mitigate the visual and cognitive demands of contemporary ROV operations. Our research investigate the effects of secondary visual tasks on operators workload and performance using standard visual navigation interface, augmented reality visual interface and audio interface. All experiments were performed on the state-of-the-art, real-time ROV simulator developed by Mobile & Marine Robotics Research Centre, University of Limerick and augmented reality system developed by Laboratory for Underwater Systems and Technologies, University of Zagreb. As expected, the results show that in no-load conditions visual guidance is better than the guidanceby-sound. By contrast, the effects of secondary visual load affect operators' performance. The use of augmented reality paradigm and especially hearing, in the form of the auditory display, emerges as an important advantage. Improvement depends on a level of experience in using auditory guidance system. Practice has a major effect on performance, bringing us to the conclusion that there is a more room for improvement in using auditory interface.

Achieving multi-Terabyte capacity in tape cartridges requires a substantially higher track density than that available in present systems, and hence a significantly higher positioning accuracy is required of the track-following servo in tape drives. In this paper, advanced concepts are considered for several elements of a tape system that enhance the track-following servo performance to reach nanometer positioning accuracy. We introduce a novel method for optimizing the geometry of servo patterns in a timing-based servo system. The design criterion aims to minimize the measurement error in the position-error signal (PES) yielded by a digital synchronous servo channel. A flangeless tape path is adopted to mitigate high-frequency components of the lateral tape motion. The track-following servo controller, which is designed based on the approach, takes into account the measured plant transfer function, the disturbance characteristics of the tape path, and the properties of servo channel. These elements are combined to investigate the track-following performance achievable with a new high-SNR magnetic tape based on perpendicularly-oriented BaFe particles. With this setup, a record closed-loop track-following performance of less than 14 nm PES standard deviation is demonstrated.

A new method for moving target detection, localization, and velocity estimation using SAR raw data is presented which allows the determination of the target's complete velocity vector. The method is applicable if the target has either a tangential velocity (I l l # 0) or a radial acceleration (~I R # 0), or both. It is based on the analysis of the Doppler rate map which is obtained from the range compressed raw data, applying the Reflectivity Displacement Method (RDM). The tangential velocity of each moving target is obtained from its own Doppler rate and the radial velocity from its own linear range migration. A velocity accuracy better than 3 m/s can be achieved for the airborne case. The method is validated experimentally by the use of real SAR data obtained by DLR's E-SAR. The paper gives a short description of the state of the art of moving target velocity measurements, introduces the RDM for stationary targets and its extension to the application for moving targets. It furthermore shows experimental results.

This paper presents a review of tilt angle and azimuth angles in solar energy applications. The paper involves an overview of design parameter, applications, simulations and mathematical techniques covering different usage application. The number of references analysing the tilt angle deployment in the context of the research papers of the different countries currently having operations in solar systems is much more significant. Different kinds of models and test methods of optimum tilt angle in different solar systems have been developed since 1956 which can be distinguished by their particular mathematical models or tracking techniques as shown in the latest researches. The mathematical models allows the calculation of different parameters of the solar radiation, the angle of inclination, and the optimum tilt angle of the collecting surface and the effects acting on the system.

and has consulted for more than ten companies in the area of indoor RF propagation and modeling, radar and sonar signal processing, RF receiver design, and inverse problems. His research interests involve applications of statistical inference to multiuser detection, blind source separation, multipath channel characterization, indoor radiolocation, and DNA sequencing algorithms. Dr. Brady served on the technical program committee of EUROSIP 2008.

A two-layer reflectarray is proposed as a central station antenna for a local multipoint distribution system (LMDS) in the 24.5-26.5 GHz band. The antenna produces three independent beams in an alternate linear polarization that are shaped both in azimuth (sectored) and in elevation (squared cosecant). The design process is divided into several stages. First, the positions of the three feeds are established as well as the antenna geometry to produce the three beams in the required directions. Second, the phase distribution on the reflectarray surface, which produces the required beam shaping, is synthesized. Third, the sizes of the printed stacked patches are adjusted so that the phase-shift introduced by them matches the synthesized phase distribution. Finally, the radiation patterns are computed for the central and lateral beams, showing a shaping close to the requirements. A breadboard has been manufactured and measured in an anechoic chamber, showing a good behavior, which validates the designing methodology.

This paper introduces a framework developed for image processing of synthetic aperture radar (SAR) images. It encapsulates features of modern hardware architectures, including symmetric and asymmetric multiprocessing, within an easy and intuitive to use application programming interface (API). The multiprocessing part is designed for unified usage of different architectures reaching from multicore processors to cluster of workstations to grids of clusters. So an application using the framework can be ported from one architecture to another without any changes in the source code. The framework builds the bottom layer of the processing system developed for the German Aerospace Center's (DLR) new airborne SAR sensor, the F-SAR [1].

We consider beamforming and Capon direction of arrival (DOA) estimation using arrays of acoustic vector sensors. We derive an expression for the Cramer-Rao bound (CRB) on the DOA parameters of a single source. Using this, we give conditions that minimize the lower bound on the asymptotic mean-square angular error, and conditions that ensure it is isotropic. The asymptotic performance of the Capon (1969, 1971) and beamforming estimators is analyzed and compared with a scalar-sensor array. The vector-sensor array is seen to have improved performance due to its elements' directional sensitivity. Large sample approximations for the mean-square error (MSE) matrices of the estimators are derived. Throughout, we compare vector-sensor arrays with their scalar-sensor counterparts

The interpolated spatial smoothing algorithm is a computationally efficient method for estimating the directions of arrival (DOA's) of signals, some of which may be perfectly correlated. It extends the spatial smoothing method to arbitrary array geometries. In an earlier paper we derived this algorithm and studied its properties. This paper provides a statistical performance analysis for the algorithm. Closed form expressions for the covariance matrix of the DOA estimation errors are derived using a perturbation analysis. Evaluating these expressions for specific cases and comparing them to the Cramer-Rao lower bound for the DOA estimates, provides insight into the statistical efficiency of this algorithm. The formulas for the error covariance are quite general, and can be specialized to provide results for other DOA estimation algorithms as well. 1883 where Dk denotes the N X N diagonal matrix 9 9 Anthony J. Weiss (S'84-M'86-SM'86) received the B.Sc. degree from the Technion-Israel Institute of Technology, Haifa, Israel, in 1973 and the M.Sc. and Ph.D. degrees from Tel Aviv Univer sity, Tel Aviv, Israel, in 1982, all in electrical engineering. From 1973 he was involved in research and development of numerous projects in the fields of communications, tracking systems, command and control, and emitter localization. In 1985 he became a faculty member of the Department of Electronic Systems, Tel Aviv University. Dunng the academic year 19861 1987 he was a Visiting Scientist with the

Uncompensated phase errors lead to quality degradation of SAR images what is especially critical for highresolution systems. In the paper, a novel approach to the stripmap autofocus is proposed. The idea of the method is to estimate the local quadratic phase errors by processing small data blocks. The conventional map-drift autofocus (MDA) algorithm is used for such estimation. Then, by a double integration of the estimated quadratic errors, an arbitrary residual phase error for large data blocks is evaluated. The performance of the proposed method is demonstrated with data obtained with an X-band airborne SAR system.

Efficient synthetic aperture radar (SAR) processing algorithms are unable to exactly implement the aperture-and topography-dependent motion compensation due to the superposition of the synthetic apertures of several targets having different motion errors and potentially different topographic heights. Thus, during motion compensation, a reference level is assumed, resulting in residual phase errors that impact the focusing, geometric fidelity, and phase accuracy of the processed SAR images. This letter proposes a new short fast Fourier transform-based postprocessing methodology capable of efficient and precise compensation of these topography-and aperture-dependent residual phase errors. In addition to wide beamwidth (very high resolution) SAR systems, airborne repeat-pass interferometry especially benefits from this approach, as motion compensation can be significantly improved, especially in areas with high topographic changes. Repeat-pass interferometric data of the E-SAR system of the German Aerospace Center (DLR) are used to demonstrate the performance of the proposed approach.