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Radar, 2006. CIE '06. International Conference on

Date 16-19 Oct. 2006

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Displaying Results 1 - 25 of 482
  • Robust Adaptive Beamforming Based on Generalized Sidelobe Cancellation

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4926 KB) |  | HTML iconHTML  

    If the desired signal is present in training snapshots, conventional adaptive beamformer is quite sensitive even to slight mismatches between the presumed and actual signal steering vectors (spatial signatures). Such mismatches can occur as a result of environmental nonstationarities, look direction errors, imperfect array calibration, distorted antenna shape, as well as distortions caused by near-far mismatch, source spreading, and local scattering. It induces signal cancellation in the traditional adaptive beamforming and severely degrades the beamforming performance. In this paper, we develop a new approach to robust GSC (generalized sidelobe cancellation)-based adaptive beamforming in the presence of an arbitrary unknown signal steering vector mismatch. The proposed method involves two steps: the first step is to use a nulling broadened blocking matrix to exclude the desired signal component from the auxiliary channels, and the second step is to obtain optimal weight by sidelobe cancellation method. Finally, simulation results demonstrate that the proposed structure can considerably enhance the overall performance. It has greatly improved robustness as compared with existing adaptive beamforming-algorithms, and enjoys simple implementation View full abstract»

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  • Processing ASAR IM Mode Data Based on Approximate Omega-K Algorithm

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3582 KB) |  | HTML iconHTML  

    This paper presents an alternating way of processing ASAR IM mode data based on approximate Omega-K algorithm. This algorithm is quite efficient because the interpolation is avoided and only two phase multiplications are required in addition to necessary FFT operations. The errors introduced by the approximation are analyzed based on the ASAR parameters. At last, the simulated point target and ASAR data are used to verify the algorithm. The experimental results show the ASAR data can be well focused View full abstract»

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  • A Novel Method for Direction of Arrival Measurement

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4202 KB) |  | HTML iconHTML  

    The radar seeker of missile under consideration uses monopulse techniques measure the target angular displacements. However, when multiple unresolved targets are present, the angular information cannot be extracted correctly. A novel method is proposed which implements a long coherent integration and the fractional Fourier transform to resolve such targets instead of the conventional Fourier transform. The accuracy of DOA measurements is guaranteed as shown in the simulation results View full abstract»

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  • Maneuvering Target Tracking Using Delayed Update Filter

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    A Kalman filter with delayed update filter (DUF) is proposed for mining the steady-state performance when tracking a constant input/bias target, while its transient performance is maintained when maneuver occurs. The key of this scheme is using a constant input/bias constraint as a pseudo-measurement to update current states estimated via Kalman filter. This constraint can remove the influence caused by mismatch of common dynamic models. Simulation results are given for comparing with the variable dimension filter and interactive multiple model filter. Benefit and validity of the proposed method is verified View full abstract»

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  • A Fast BAVQ Algorithm For SAR Raw Data Compression

    Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2752 KB) |  | HTML iconHTML  

    In this paper, a fast BAVQ algorithm in SAR raw data compression is proposed. First, to reduce the data dynamic range, block adaptive quantization of raw data is implemented and the sign bit of raw data is coded separately. And then, VQ is applied in the absolute value of the raw data. The result of experiments shows that the complexity of VQ has been greatly reduced and the process of searching codebook can be simplified View full abstract»

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  • Suppression of Azimuth Ambiguities with Constellation of Micro-satellites

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3723 KB) |  | HTML iconHTML  

    To achieve wide-swath and full azimuth resolution in space-borne synthetic aperture radar (SAR), a space-borne radar usually utilizes low pulse repetition frequency (PRF) with a small aperture in azimuth. Consequently, the azimuth ambiguities are inevitable. As one solution to this problem, space domain filter can be utilized to remove the azimuth ambiguities based on the configuration of micro-satellites distributing along track. In this paper, an innovative method is proposed to simplify the calculation of the filter weight vectors. Simulation shows the validity of the method View full abstract»

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  • Research on the Technology of RFSS in Large-scale Universal Missile ATE

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3838 KB) |  | HTML iconHTML  

    This paper addressed the application technology of radio frequency simulation system (RFSS). The realization was applied to a large-scale universal missile automatic test equipment (ATE). Mathematic model and operating principle of two most important kinds of final guidance radar RF simulation system were described, including pseudo-coherent frequency agile radar and pulse Doppler (PD) radar. We developed an integrated system with modularization configuration, which was characterized by its versatility and expandability View full abstract»

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  • Phase Cancellation for Synthesizing Range Profile of Target with Micro-motion

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3381 KB) |  | HTML iconHTML  

    Micro-motion, such as nonuniform motion, induces complex range-Doppler coupling effect, which results in distortion in synthesizing range profile. To eliminate or suppress the distortion of the synthetic range profile (SRP), conventional technology such as motion compensation requires velocity estimation. Unfortunately, for a high-speed moving target with micro-motion, it is difficult to achieve real-time accurate estimation of the velocity of the target Based on phase cancellation; a new technology is proposed to achieve range profile of a target with micro-motion via stepped-frequency waveform (SFW). The emulation result confirms the effect of the new technology View full abstract»

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  • Performance Analysis for Random Noise Ultra-Wideband Radar Signal

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4425 KB) |  | HTML iconHTML  

    The random noise ultra-wideband radar signal is introduced and its power spectral function is also given. Through the theoretical analysis and simulation, the statistical peak sidelobe level (PSL) of compression wave of the correlation receiver and the resolved ability are studied. The simulative result proves that the random noise ultra-wideband radar signal possesses lower PSL in a certain condition and better resolved ability with the comparison of the linear frequency modulated ultra-wideband radar signal View full abstract»

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  • On multivariate matrix Pade-type approximants

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3705 KB) |  | HTML iconHTML  

    Following naturally the same ways as Brezinski developed in the scalar case and Draux in the matrix scale, the author constructs a kind of generalized multivariate rectangular matrix Pade-type approximants on a rectangular grid, choosing an arbitrary monic bivariate polynomial as the generating one of the approximant, discusses their several typical important properties and studies the connection between generalized bivariate rectangular matrix Pade-type approximants and Pade approximants. The arguments given in detail in two variables can extend directly to the case of d variables (d>2) View full abstract»

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  • Robust Constrained LMS Adaptive Beamformer

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4042 KB) |  | HTML iconHTML  

    In the paper, an approach is proposed for robust constrained LMS beamforming in the presence of pointing error, array geometry error and sensor phase error (generalized as array phase errors). The basic idea is to search the optimal weight vector with constrained LMS update, and jointly search the actual array steering vector of the desired signal based on steering vector-expanded algorithm. Despite its lower computational complexity however, it turns out that the proposed algorithm has improved performance. Compared with other recursive beamformers, simulations in the presence of given errors demonstrate that the presented algorithm has more effective and robust performance View full abstract»

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  • Improved Classification of Polarimetric SAR Data Based on Four-component Scattering Model

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4605 KB) |  | HTML iconHTML  

    In this, paper, we propose an improved classification algorithm which is based on the four-Component scattering model. Compared with the three-component model introduced by Freeman and Durden, the four-component scattering model introduces the "helix scattering" as its fourth component. Our algorithm emphasizes the existence of pixels with mixed scattering mechanism, and applies the result of decomposition as feature vector to initial merge and final iterative classifier instead of using the Wishart distance. We use L-band Pi-SAR images to demonstrate this new method. The experimental result verifies the effectiveness of this improved algorithm View full abstract»

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  • Chirp-Pulse Stepped-Frequency Radar Based on Decorrelation Processing

    Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2454 KB) |  | HTML iconHTML  

    This paper introduces a novel method based on decorrelation processing to solve the energy-spillover problem in conventional chirp-pulse stepped-frequency radar processing in order to achieve high range resolution. Compared with previously proposed methods, this method is much simpler to be realized in engineering. Its principle is analyzed in this paper, and its performance is confirmed by simulation results View full abstract»

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  • Evaluation of the Aperture in the Curvilinear SAR

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3800 KB) |  | HTML iconHTML  

    The curvilinear synthetic aperture radar (SAR), as a more practicable three-dimensional (3-D) SAR imaging system, has to utilize the parametric methods to extract the target features from its received data, the sparse data in 3-D frequency space. With the obtained feature estimates, these parametric methods, who can efficiently remove the effects of the sidelobes, reconstruct the target image whose quality is affected by the estimation accuracy of the features. By minimizing the Cramer-Rao bounds (CRBs) of the target features, we show, in this paper, the different effects on the estimation accuracy of different aperture parameters. A feature-independent aperture evaluator is also given for the curvilinear SAR system View full abstract»

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  • Design of the High-powered Digital Pulse Compression Real-time Processing System Based on ADSP-TS203

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3230 KB) |  | HTML iconHTML  

    In the modern radar pulse compression system the real-time processing is important besides simplifying the design of software and hardware. In this paper, the newest general-purpose DSP TS203 of ADI Company is applied to realize the real-time processing of the pulse compression in frequency domain. Registers configure and addressing methods to implement the pulse compression are discussed in detail. Results of simulation and system test show that it can ensure real-time processing and all parameters can also meet the requirements View full abstract»

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  • Detection of Ultra-High Speed Moving Target Based on Matched Fourier Transform

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4199 KB) |  | HTML iconHTML  

    Ultra-high speed moving target is a new case falls across in modern radar target detection. The echo model of the ultra-fast moving target is founded in this paper, and its effect on pulse Doppler processing is analyzed. Then we propose a new algorithm of pulse Doppler processing based on matched Fourier transform (MFT). According to the characteristic of the echo, we propose an algorithm to realize MFT-based target detection which has light computation load, clear physical meaning and strong searching range pertinence. The simulation results show the validity of the algorithm View full abstract»

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  • Bistatic Radar DPCA Technique

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3469 KB) |  | HTML iconHTML  

    This article gives the spatial geometry model of bistatic radar displaced phase center antenna (DPCA) technique based on two-antenna. The bistatic radar DPCA technique requires that the distance between the two transmitting antenna phase centers (d), the pulse repetition interval (PRI) and the speed of the moving platform (Va) are strictly associated, just as the monostatic case. When the speed of the moving platform fluctuates, we can suppress clutter and detect moving target by interpolating and registering. The validity of the theoretic analysis is proved by simulation View full abstract»

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  • Tree Structure for Channelized Digital Receivers

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2871 KB) |  | HTML iconHTML  

    A new structure to build channelized receivers is proposed in this paper. Channelization is always achieved once time in conventional structure. But in the proposed structure, it is realized step by step with a tree filterbank. Basic unit of the filterbank is composed of symmetrical halfband filters. The filterbank is computationally efficient since half of the filter coefficients are zeros. Polyphase decomposition makes it more efficient because two symmetrical halfband filters are shared and one of the polyphase filters become a constant. The structure is not only used in uniform channelization, but also suitable for nonuniform channelization with basic units substituted by delay units View full abstract»

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  • Clutter Reduction Based on Apex Shifted Radon Transform in Sub-surface Forward-Looking Ground Penetrating Radar

    Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3206 KB) |  | HTML iconHTML  

    In this paper a method is proposed to reduce none-apex hyperbola clutter due to target being located at the outside of imaging region and the inside of electromagnetic wave field in forward-looking ground penetrating radar (FLGPR) measurements. This clutter reduction method is based on apex shifted Radon transform which maps the none-apex hyperbola clutter in radargram to an energy congregate region in the tau-q domain. The none-apex hyperbola clutter is estimated by using a q band-pass filter and the inverse transform. Then the estimated clutter is removed by subtraction method. Finally, remainder surface clutter is reduced by scale and shift. The effectiveness of the approach is demonstrated with an experimental data set, and it increases the signal-to-clutter ratio of near-surface target View full abstract»

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  • Real-time Signal Processing Implemention of the Missile-Borne SAR Using High performance DSP

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3327 KB) |  | HTML iconHTML  

    In this paper, firstly the theoretical analyses of the traditional SAR imaging processing are made the time-domain sub-aperture algorithm which is used to implement missile-borne SAR are researched and a hardware system using the high performance DSP chip named TS203 to process digital signal practically are designed and the result of imaging are given View full abstract»

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  • The Principle and Performance Analysis of Profile Clutter map

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3395 KB) |  | HTML iconHTML  

    The paper discusses the principle of radar profile clutter map and its corresponding algorithm. The performances of false alarm control and the detection performance of clutter are analyzed under the condition of Rayleigh distribution. When the system parameters are determined, the paper analyzes the affection to the detection probability corresponding to the number of repeat impulses, iterative coefficient and the average clutter-to-noise ratio in different false alarm probability, and so, the realization of building profile clutter map in low clutter-to-noise ratio is available. The simulation examples can demonstrate the validity of algorithm View full abstract»

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  • Doppler Frequency-Only and T2 / R Radar Based Moving Target Location

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3739 KB) |  | HTML iconHTML  

    Bi/multi-radar using cooperative or non-cooperative transmitters has attracted much attention in the international community. This paper analyzes performance of the locating a moving target from corrupted Doppler frequency measurements obtained by a single receiver with two cooperative or non-cooperative transmitters. And the expressions for the Cramer-Rao bound are derived. Finally, we get the meaningful conclusion that the radar can exploit the excellent Doppler information to locate moving target accurately View full abstract»

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  • Considerations for Non-cooperative Bistatic SAR with Spaceborne Radar Illuminating

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3672 KB) |  | HTML iconHTML  

    Bistatic radar, especially illuminating of opportunity, has recently been one of interesting research hotspot due to its military stealth and economic advantages. In this paper, we consider non-cooperative bistatic SAR using aircraft as receiver and spaceborne radar as illuminating of opportunity. Firstly, we qualitatively descript the relationship between geometry and resolution of bistatic SAR. Then, we study receiver geometry configuration from imaging resolution and receiving data aspects. Theoretical analysis shows that observation time has relation with the azimuth initial position of receiver beam footprint, which is relative to transmitter beam footprint, and footprint velocity of transmitter and receiver respectively. Through example calculation, we find that observation time have weak relation with the aircraft velocity and strong relation with the azimuth initial position of receiver beam footprint, which is relative to transmitter beam footprint The imaging area mainly depends on observation time and aircraft velocity and receiver main lobe beamwidth. Finally, simulations demonstrate that non-cooperative bistatic SAR system, in our case, can possess a short observation time range (l-3s) View full abstract»

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  • Radar Emitter Signal Fractal Feature Based on Wavelet Transform

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4138 KB) |  | HTML iconHTML  

    Fractal feature can describe the complexity of radar emitter signal. Wavelet transform cannot only observe signal general framework and detail, but also reduce influence of noise. Hence wavelet transform can combine with the fractal theory to study the fractal feature of radar emitter signal. First, signal is decomposed by wavelet transform, and then fractal dimension is computed in different decomposition levels, so the signals with different complexity have different fractal dimensions. In the end the simulation experiments validate that this method is effective to distinguish radar emitter signal View full abstract»

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  • Two-dimensional Zero Intermediate Frequency Vector Filtering Method for SAR Interferograms

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3398 KB) |  | HTML iconHTML  

    This paper presents a new filtering algorithm for SAR interferograms. The proposed algorithm assimilates the idea of zero intermediate frequency (ZIF) in radio technique. It transforms the raw interferogram to the zero intermediate frequency (ZIF) one and then filters it by vector filter. So, it is called as zero intermediate frequency vector (ZIFV) filtering. Firstly, the raw interferogram is mapped to a vector interferogram, which includes the sine signal and the cosine one. Secondly, the vector interferogram is transformed to spectrum by using two-dimensional fast Fourier transform (FFT). Thirdly, the zero intermediate frequency is calculated and then a new reference interferogram is derived from it. And then, the ZIFV interferogram is calculated from the reference interferogram and the raw interferogram. Finally, the ZIFV interferogram is filtered by vector filtering method and the filtering result of the raw interferogram is obtained. Experiments show that the new ZIFV filtering algorithm can resolve the difficulty in dealing with dense fringe in SAR interferograms. The filtering effect is excellent for interferograms, especially for dense fringes View full abstract»

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