By Topic

Date 21-23 May 2008

Filter Results

Displaying Results 1 - 25 of 88
  • Smart beamforming and wideband signals for ground surveillance

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2416 KB) |  | HTML iconHTML  

    In this paper, dealing with long range ground surveillance radars, it is shown that the simultaneous requirement for wideband waveforms and multiple channels opens the way to new space-time signals and processing techniques, thus improving the detection and classification of multiple ground (and low-flying) targets. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Evolutions of mathematical statistics and corrections to CFAR and STAP theories

    Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    Since Fisherpsilas maximum likelihood (ML) method is correct only for asymptotically great number of samples, the exile of Bayessian approach from mathematical statistics (MS) hampered development of CFAR and STAP theories. Many heuristic corrections to these theories appeared therefore. But, it seems better to begin creating the generalized Bayessian theory, providing the processing algorithms for fast varying conditions. The new Pareto-Gaussian a priory model of total interference (TI) intensity is therefore reasoned. Investigation of its use in CFAR and STAP theories is begun. The contours are outlined of future combination of such theories with fast progress in ldquoknowledge aided signal processingrdquo. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Radar for small distances with phase ring detector

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (172 KB) |  | HTML iconHTML  

    An idea of a radar for measurements of small distances operating in a millimeter band is presented in the paper. Phase ring detectors were used for radar development which simplified radar structure. Algorithms for conversion of output voltages in the microwave part of the radar are also presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the occurrence of ghost targets in linear FMCW radar: A worst case study

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (150 KB) |  | HTML iconHTML  

    In LFMCW (linear frequency modulated continuous wave) radar, there is a nonzero probability for mismatches to occur under certain conditions. We show that this probability strongly depends on the modulation employed as well as on the distribution of targets. Hence a good approach to reduce mismatches is to carefully design the modulation used. Instead of utilizing extensive simulations based on target statistics to accurately estimate the probability of mismatches, we characterize a modulation in terms of its worst case number of mismatches possible. The focus of this paper is to identify conditions for the worst case and to deduce general rules for the modulation design. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Theoretical investigation of a novel location sensor

    Page(s): 1 - 2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (145 KB) |  | HTML iconHTML  

    We report a theoretical investigation of a novel location technique implemented using millimeter waves. The new technique is based on multiple correlated receivers, fast digital signal processing and electronically tuned transmitters (tags). The correlated receivers synthetically generate multi-beam with an aperture much larger than the actual aperture, resulting in beam-width much narrower than that produced by conventional arrays with the same number of elements, and hence very fine angle resolution. Altogether, these allow multiple tags to be simultaneously and accurately detected and located in real time. The entire area can be searched rapidly from a fixed position where the sensor is mounted without physically moving the antenna or using external beam control devices such as phase shifters as in conventional phased arrays, largely eliminating errors due to these components and ultimately help improving the system performance. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Complex Polarization Angle: Basic properties and applications in microwave plasma diagnostics

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (187 KB) |  | HTML iconHTML  

    Evolution of electromagnetic waves in weakly anisotropic media can be described adequately by quasi-isotropic approximation (QIA) of geometrical optics method. At this paper, QIA equations are presented in a compact form by involving the complex polarization angle (CPA). Relations between CPA and traditional parameters of polarization ellipse are established. Besides, equations for CPA and for traditional polarization parameters are derived for EM waves, propagating in the inhomogeneous magnetized plasma accounting both Faraday and Cotton-Mouton effects. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High power and linearity CMOS RFIC transmit-receive switch for ultra-Wideband radar and communication systems

    Page(s): 1 - 2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (157 KB) |  | HTML iconHTML  

    We report on the development of an ultrawideband fully-integrated T/R switch, fabricated on a commercial standard 0.18-mum CMOS process, with unprecedented performance. It occupies a very small die area of 230 mum times 250 mum. The new T/R switch employs an ultrabroadband topology based on the synthetic transmission-line concept with on-chip spiral inductors. Simultaneously floating and applying negative bias to the bulk or positive bias to the drain are implemented to enhance the linearity and power handling of the switch. The developed CMOS T/R switch exhibits an insertion loss lower than 1 dB from DC to 18 GHz and less than 2.5 dB up to 20 GHz. The measured isolation is between 32-60 dB, 25-32 dB, and 25-27 dB and P1dB varies between 25.4-26.2 dBm, 22.6-25.4 dBm, and 19.8-22.6 dBm from DC-10 GHz, 10-18 GHz, and 18-20 GHz, respectively. The measured input third-order intercept point (IIP3) reaches as high as 41 dBm. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance of two-dimensional parametric STAP: KASSPER airborne radar data analysis

    Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (100 KB) |  | HTML iconHTML  

    We investigate a new class of 2D parametric models for space-time adaptive processing (STAP) of ground clutter in airborne radar using KASSPER Dataset 1. The signal-to-interference-plus-noise (SINR) degradation with respect to the optimal receiver is analyzed for various parametric models, regularizations and training sample volumes. We show that a very small training sample volume (5-15 training range bins), with a suitable parametric model and estimation technique, can give acceptable STAP performance for the KASSPER scenario. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The eigencanceler as a uniform most powerful invariant test applied to spatial processing for jammer mitigation

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (214 KB) |  | HTML iconHTML  

    The eigencanceler (EC) is a subspace detector that has been suggested in the last years as a robust and fast-converging alternative to GLRT-related methods for space-time adaptive radars. In this paper we consider the EC from an original invariance-based point of view for the problem of spatial anti jamming, where interference is not required to be normally distributed. We compare the performances of the EC and the standard adaptive matched filter for the problem considered, in term of signal to noise + interference ratio for both Gaussian and non-Gaussian interference. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-resolution clutter-power estimation for range-dependence compensation in conformal-array STAP

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (605 KB) |  | HTML iconHTML  

    We consider space-time adaptive processing (STAP) when the radar returns are recorded by a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimate the optimum weight vector are not identically distributed with respect to range, thus preventing the STAP processor from achieving its optimum performance. The compensation of the range dependence requires the precise knowledge of the clutter power contained in the secondary data. We propose anew MVDR-based clutter power estimator applied to temporally-smoothed secondary data to obtain an accurate estimate of the expected clutter power This estimate allows one to perform an accurate range-dependence compensation leading to a valid estimate of the clutter covariance matrix. End-to-end performance analysis in terms of signal to inference plus-noise ratio loss shows promizing performance. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Practical problems with covariance matrix estimation for adaptive MTI and space-time adaptive processing for target detection in HF surface wave radars

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (65 KB) |  | HTML iconHTML  

    Surface wave over the horizon radar systems have a potential to detect targets, that are hidden under optical horizon. This possibility is, however, difficult to implement as a result of first and second order clutter scattered from the ocean surface in combination with interferences. In this paper we compare adaptive MTI and space-time adaptive processing algorithms applied to the surface wave high frequency radar system data. The aim of the experiments was to evaluate different techniques and their usefulness to detect targets at distances 50-200 km off shore. In the experiments authors used the data from an oceanographic, surface-wave, high frequency system WERA, designed to perform continuous monitoring of sea currents and waves. Data were collected at the west coast of France, in Brittany. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • STAP/GMTI analysis using SAR data from simulated scenarios

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (553 KB) |  | HTML iconHTML  

    The surveillance of ground areas is one of the essential tasks for modern manned and autonomous flying platforms. Especially a SAR/GMTI sensor is essential because itpsilas all weather capability, but often demands large size antennas which must be designed under aerodynamic aspects with compromises regarding the ideal SAR processing need. The customerpsilas exigency for long-term observation capabilities requires furthermore the employment of automatic recognition systems. Both aspects require a SAR sensor design to platform, to performance and not at least to costs. This paper presents a performance assessment tool for both aspects, i.e. the influence of antenna imperfectnesspsilas to the (coherent & multi-channel) SAR data and also the impact to the target recognition capability. The tool combines the EADS SAR simulation program ldquoPIRDISrdquo which is able to deal with nearly arbitrary antenna patterns and produces coherent multi-channel signals in the range/Doppler domain, with a new ldquoground moving target indicationrdquo (GMTI) module working in the post-Doppler modus. The plot extractor regards only that information available also in an operational system and delivers (moving) target alarms (and also false alarm candidates, depending on scenarios and radar parameters). The results are compared with the ground truth known from the scenario generation in terms of accuracy of localisation, probability of detection and false alarm sensitivity. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A 77-GHz FMCW front-end with FPGA and DSP support

    Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (191 KB) |  | HTML iconHTML  

    Recent advances in the development of semiconductors allow the realization of low cost 77-GHz radar front-ends suitable for automotive applications. The requirements on the angular resolution often force designers to implement antenna arrays. In the last decade the trend moves towards digital array processing instead of analog beamforming because of the availability of cheap digital signal processors (DSP). In the case of an n-element receive array, the system must be capable of processing n receive channels in parallel resulting in a big amount of data. Field programmable gate arrays (FPGA) deliver the processing power and flexibility to handle the collected data and allow, in conjunction with a DSP, the implementation of sophisticated signal processing algorithms. This paper deals with the implementation of a 77-GHz frequency modulated continuous wave (FMCW) prototype radar system. The system is designed for use in array processing applications, with a maximum of eight parallel receive channels. The functionality of the prototype system is demonstrated in an imaging application. With the help of a portal axis the radar is moved along a synthetic aperture in order to reconstruct the reflectivity map of the imaging area. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The instability measurements for the unmanned aerial platform as a radar carrier

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (258 KB) |  | HTML iconHTML  

    The paper presents the testbed for the UAS instability measurements. The testbed consists of the aerial vehicle of the miniUAV class. The airplane is equipped with the sensor suite built upon several sensing devices: gyroscopes, accelerometers, magnetometers, GPS receiver and pressure sensors. The data from the sensors is combined in the on-board sensor fusion processor and then transmitted to the ground control station. The aerial vehicle that was acting as a carrier platform is a regular UAV being an equipment of one of the European armies. The testing results show the flying platform instabilities that can be expected during the synthetic aperture radar mission onboard the miniUAV airplane. Several measurements have been taken and the instability characteristics are presented and discussed. The aim of such measurements is to find out the starting point for design of the stabilized platform to be built onboard the UAV. The platform requirements drawn from the presented measurements are taken into account in the review of the possible stabilization solutions. The stabilized platforms were discussed with the respect of the SAR requirements. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The application of CW monopulse tracking radar for performance evaluation of artillery shells and its performance comparison against DGPS and simulation results

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (203 KB) |  | HTML iconHTML  

    Tracking radar plays an important role in parameter evaluation of artillery shells during development and production stage. CW Monopulse radar is capable of giving more number of trajectory parameters with high degree of accuracy and reliability. This paper mainly deals with the test firing configuration for measurement of parameters like trajectory coordinates, velocity, height of functioning and drift from line of fire. Dynamic firing aspects of above parameters are covered and data acquisition from a monopulse receiver are presented. Projectile range is measured using DGPS (Differential Global Positioning System). Measurement results obtained from tracking radar are compared with DGPS and simulation results. This paper also deals with different sources of random and systematic errors that affect the measurement accuracy of tracking radar system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A multi-scaled registration algorithm for radar image and electronic chart

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (461 KB) |  | HTML iconHTML  

    Radar detection is a useful technique in ship navigation and collision avoidance, especially in bad weather conditions. However, radar image cannot show the actual location of target in the electronic chart directly. In order to solve this problem and comprehensively utilize the information of both radar and electronic chart, the two images should be matched beforehand. In this paper, a multi-scaled registration algorithm for radar image and electronic chart is presented. Based on the scale-space theory, coastlines from the two images are matched in both phase domain and image domain with continuous scale level. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance analysis of a cylindric dielectric lens antenna for 77 GHz automotive radar

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (75 KB) |  | HTML iconHTML  

    This paper introduces a novel dielectric lens antenna configuration for automotive radar applications. A cylindric lens fed by a uniform linear array (ULA) accomplishes elevation beam shaping and simultaneously allows for the application of array signal processing in the azimuth plane. Measured and simulated radiation patterns show a superior performance compared to a conventional antenna concept without lens. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dual polarized traveling wave antenna for Ultra Wideband radar application

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (531 KB) |  | HTML iconHTML  

    This paper introduces a development of a compact dual polarized traveling wave antenna for Ultra Wideband technique. A principle of the antenna is introduced as well as its development. Subsequently the measurements results are shown including the time domain analysis of the antenna behavior. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Microstrip quasi-horn antenna for UWB radars and sensors

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (293 KB) |  | HTML iconHTML  

    A microstrip quasi-horn antenna for UWB radars and sensors has been developed. The antenna achieves good performance in both frequency domain for CW signals from 0.3-6 GHz and time domain for monocycle pulses of various durations. The time-domain measurement, particularly, shows that the antenna can transmit and receive monocycle pulses effectively with minimum distortion, little ringing, and small reflection, clearly demonstrating the signal fidelity of the antenna in reproducing the waveform of UWB signals which is critical for UWB radars and sensors. For time-domain applications, such as UWB radars which transmit and receive pulse signals, characterizing the antenna's transient responses directly is useful and important for accurate assessment of its signal fidelity and matching. The developed antenna employs non-uniform microstrip transmission line and has good linear phase, simple fabrication, and easy integration with microwave integrated circuits. It requires no transition or balun at its input, leading to wide bandwidths and high operating frequencies. The antenna has been successfully used in several UWB surface-penetrating radars. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An ultra-Wideband uniplanar antenna for UWB systems

    Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (211 KB) |  | HTML iconHTML  

    The development of a new compact uniplanar antenna operating from 3.1 to 10.6 GHz for ultra-Wideband (UWB) systems is presented. The antenna overcomes potential problems caused by the coupling between the feed and antenna and meets the requirements for UWB applications, such as ultra-wide bandwidth, reasonable efficiency, satisfactory radiation properties, and linear phase characteristics. It occupies only 1.2 in times 1.4 in on a Duroid substrate having 0.025-in thickness and relative dielectric constant of 10.2. The antenna has excellent time-domain performance particularly crucial for UWB time-domain impulse applications. Its planar structure facilitates integration with printed-circuit UWB transmitters and receivers. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Applying the neural networks to formation of radiation pattern of microstrip antenna

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (174 KB) |  | HTML iconHTML  

    Artificial Neural Networks (ANN) have recently gained attention as a fast and flexible vehicle to microwave modelling, simulation and optimization. This paper provides an overview on the possibility of applying artificial neural networks to the process of shaping the profile (radiation pattern) of microstrip antenna array. Neural network based algorithms, due to heavy use of parallelism, considerably accelerates the process. By appropriate selection of teaching data, near real-time solution may be archived. Algorithm has been tested in MATLAB environment using neural network modelling utility ldquoFlex Toolrdquo. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Polarization invariants of radar complex random objects

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (738 KB) |  | HTML iconHTML  

    It is proposed in this paper in order to use as a polarization invariant of a complex radar object the value ldquopolarization proximityrdquo of this object separate secondary scatterers polarization states or a value ldquopolarization states distancerdquo of secondary scatterers. A presentation of these values and their interpretation are considered. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • New method of the radar images compression for the needs of navigation in marine traffic

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (153 KB) |  | HTML iconHTML  

    The paper presents a new concept of the lossless radar images compression method for the needs of the navigation in marine traffic. A fundamental problem of vessel operation in marine transport is increasing safety level of own shipping and vessels cooperating. We can receive this aim using various ways. One of them is radar images compression method for the needs of the remote transmission. The radar image is one of the major source of navigational data. To decrease size of data under transmission a new algorithm, namely RLE-BER, for radar images compression was firstly proposed by Lisaj et. al. (2007).Now we are presenting in our papers practical results on real navigational data and provide same discussion on future plans in the way of verification binary methods. After experimental research we received value of the compression ratio near 5:1 and this result is very optimistic for the next step in our scientific research. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new approach for ARPA display and collision danger assessment

    Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (92 KB) |  | HTML iconHTML  

    A suitable approach to support human navigators in proper use of radar equipment including ARPA is to provide adequate information and its display for decision-making. In this paper, a new approach of ARPA display is proposed. We define the range of course at risk (RCR) and the range of speed at risk (RSR) and display them on an outer ring of the radar screen and heading mark, respectively. A fuzzy method is employed for determining the radius of the guarding ring and a basic configuration of a fuzzy logic system for collision avoidance is proposed. We also propose two measures for estimating collision danger, the heading risk (HR) and the situational risk (SR). HR indicates the danger level of own shippsilas present course and speed, and SR indicates the general danger level of surrounding traffic. With our new display approach, the decision making becomes straight and no trial maneuver is needed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The elimination of ambiguous measurements in radar with wobbled impulses

    Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (793 KB) |  | HTML iconHTML  

    In the given work the method of elimination of range measurements ambiguity in pulse radar survey type with use of multiple repetition frequencies of probing impulses is considered. The work algorithm of the scheme is analyzed; the analysis of results of the device work modeling with use of detection characteristics is made. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.