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Effects of residual motion compensation errors on the performance of airborne along-track interferometric SAR Article

Hui ZHANG,Jun HONG,Xiao-lan QIU,Ji-chuan LI,Fang-fang LI,Feng MING

Frontiers of Information Technology & Electronic Engineering 2016, Volume 17, Issue 10,   Pages 1095-1106 doi: 10.1631/FITEE.1500311

Abstract: Two approximations, center-beam approximation and reference digital elevation model (DEM) approximation, are used in synthetic aperture radar (SAR) motion compensation procedures. They usually introduce residual motion compensation errors for airborne single-antenna SAR imaging and SAR interferometry. In this paper, we investigate the effects of residual uncompensated motion errors, which are caused by the above two approximations, on the performance of airborne along-track interferometric SAR (ATI-SAR). The residual uncompensated errors caused by center-beam approximation in the absence and in the presence of elevation errors are derived, respectively. Airborne simulation parameters are used to verify the correctness of the analysis and to show the impacts of residual uncompensated errors on the interferometric phase errors for ATI-SAR. It is shown that the interferometric phase errors caused by the center-beam approximation with an accurate DEM could be neglected, while the interferometric phase errors caused by the center-beam approximation with an inaccurate DEM cannot be neglected when the elevation errors exceed a threshold. This research provides theoretical bases for the error source analysis and signal processing of airborne ATI-SAR.

Keywords： Synthetic aperture radar (SAR)     Along-track interferometric     Motion compensation     Residual error     Interferometric phase    

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A general method of designing phase-shifting algorithms for grating lateral shearing interferometry None

Chao FANG, Yang XIANG, Ke-qi QI

Frontiers of Information Technology & Electronic Engineering 2018, Volume 19, Issue 6,   Pages 809-814 doi: 10.1631/FITEE.1601692

Abstract: We propose a general method of designing phase-shifting algorithms for grating lateral shearing interferometry. The algorithms compensate for the zeroth-order effect error and phase-shifting error in varying degrees. We derive a general expression of the phase-shifting algorithm in grating lateral shearing interferometer and introduce the corresponding design method. Based on the expression and method, four phase-shifting algorithms are designed with different phase-shifting errors to obtain high measurement accuracy. A new 13-frame phase-shifting algorithm is designed and simulated with a large zeroth-order effect. Simulation results verify the general expression and the corresponding design method.

Keywords： Interferometry     Phase measurement     Phase-shifting algorithms    

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Virtual-position Reading Method—a Novel Method for Error Motion and Form Error Separation

Hong Maisheng,Li Zijun,Su Heng,Ye Feifan

Strategic Study of CAE 2002, Volume 4, Issue 10,   Pages 48-51

Abstract:

On the basis of signal re-organization, a novel method named virtual-position reading method is proposed in this paper. By means of this method, form error or error motion can be respectively separated according to practical needs, and the separating sequence of form error or error motion can also be optional. Furthermore, in the proposed method, it is not necessary to change the conventional measuring and separating system of form error or the normal procedures of separating operation. It is proved that the new method is flexible and convenient in use.

Keywords： virtual-position reading     signal re-organization     form error     error motion     error separation techniques    

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Measurement and Information Technology

Zhang Guoxiong

Strategic Study of CAE 2000, Volume 2, Issue 3,   Pages 62-66

Abstract:

Measurement is an important means for obtaining information in research and production. Both the quality of products and the productivity of production highly depend on measurement. An important trend in the development of measurement is its merging with information technology. The requirements in high accuracy of measurement, on-line and dynamic measurements, measurements of complicated parameters and under complex conditions and intelligent measurements ask for the merging of measurements with information technology. This merging is carried out through the whole process. Modulation and demodulation, data sampling and reconstruction, signal merging, data compression, filtering, signal transformation, time series analysis, spectrum analysis, data fitting and modeling, pattern recognition, neural network, simulation and virtual measurement, error separation, error compensation, redundancy technique, decision making, intelligent techniques, etc. , are widely used in measurements. Some practical examples of this merging are given in the paper. The accuracy of coordinate measuring machines (CMMs) can be greatly enhanced by using error compensation technique. Modeling, error calibration and compensation software are three key techniques in error compensation of CMMs. Applications of redundancy technique in roundness and spindle error motion measurement, in large scale metrology are presented as well. Redundancy technique provides a powerful means in optimization of measurements, system self-calibration, error compensation, recovering the lost information and many other applications.

Keywords： measurement     information technology     error compensation     modeling     redundancy technique     error separation    

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Phase problems in optical imaging Review

Guo-hai SITU, Hai-chao WANG

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 9,   Pages 1277-1287 doi: 10.1631/FITEE.1700298

Abstract: Because the phase contains more information about the fieldcompared to the amplitude, measurement of the phase is encounteredin many branches of modern science and engineering. Direct measurementof the phase is difficult in the visible regime of the electromagneticwave. One must employ computational techniques to calculate the phasefrom the captured intensity. In this paper, we provide a review ofour recent work on iterative phase retrieval techniques and theirapplications in optical imaging.

Keywords： Phase retrieval     Phase imaging     Computational imaging     Gerchberg-Saxton algorithm     Optical encryption     Computer-generated hologram    

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Forward link outage performance of aeronautical broadband satellite communications Research Articles

Huaicong Kong, Min Lin, Shiwen He, Xiaoyu Liu, Jian Ouyang, Weiping Zhu,linmin@njupt.edu.cn

Frontiers of Information Technology & Electronic Engineering 2021, Volume 22, Issue 6,   Pages 790-801 doi: 10.1631/FITEE.2000445

Abstract: High-throughput satellites (HTSs) play an important role in future millimeter-wave (mmWave) aeronautical communication to meet high speed and broad bandwidth requirements. This paper investigates the outage performance of an aeronautical broadband satellite communication system’s forward link, where the feeder link from the gateway to the HTS uses and the user link from the HTS to aircraft operates at the mmWave band. In the user link, spot beam technology is exploited at the HTS and a massive antenna array is deployed at the aircraft. We first present a location-based beamforming (BF) scheme to maximize the expected output signal-to-noise ratio (SNR) of the forward link with the amplify-and-forward (AF) protocol, which turns out to be a phased array. Then, by supposing that the FSO feeder link follows Gamma-Gamma fading whereas the mmWave user link experiences shadowed Rician fading, we take the influence of the into account, and derive the closed-form expression of the (OP) for the considered system. To gain further insight, a simple asymptotic OP expression at a high SNR is provided to show the diversity order and coding gain. Finally, numerical simulations are conducted to confirm the validity of the theoretical analysis and reveal the effects of s on the system outage performance.

Keywords： 航空宽带卫星网络；自由空间光传输；高通量毫米波通信；中断概率；相位误差    

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A multi-functional dynamic state estimator for error validation: measurement and parameter errors and sudden load changes Article

Mehdi AHMADI JIRDEHI,Reza HEMMATI,Vahid ABBASI,Hedayat SABOORI

Frontiers of Information Technology & Electronic Engineering 2016, Volume 17, Issue 11,   Pages 1218-1227 doi: 10.1631/FITEE.1500301

Abstract: We propose a new and efficient algorithm to detect, identify, and correct measurement errors and branch parameter errors of power systems. A dynamic state estimation algorithm is used based on the Kalman filter theory. The proposed algorithm also successfully detects and identifies sudden load changes in power systems. The method uses three normalized vectors to process errors at each sampling time: normalized measurement residual, normalized Lagrange multiplier, and normalized innovation vector. An IEEE 14-bus test system was used to verify and demonstrate the effectiveness of the proposed method. Numerical results are presented and discussed to show the accuracy of the method.

Keywords： Dynamic state estimation     Kalman filter     Measurement errors     Branch parameter errors     Sudden load changes    

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A comprehensive error calibration method based on dual uniform circular array Research Article

Jia-jia Zhang, Hui Chen, Song Xiao, Meng-yu Ni,zjj2015wuhan@163.com

Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 10,   Pages 1415-1428 doi: 10.1631/FITEE.1800240

Abstract: Based on the , a novel method is proposed to estimate the direction-of-arrival (DOA) and jointly calibrate , , and . In this paper, only one auxiliary source is required to generate three time-disjoint sources with the help of the rotation platform. Subsequently, according to the principle that the signal subspace is orthogonal to the noise subspace, the cost function is constructed. The alternating iteration method is used to estimate the coefficients of the three kinds of errors. During the process, the proposed algorithm makes full use of the structural characteristics of the array when estimating , while the signal phase matrix is used to eliminate the phase influence caused by the delay in signal arrival at the antenna array when estimating and . Compared with the algorithm using multidimensional nonlinear search, the proposed algorithm has lower computational complexity. Moreover, our algorithm does not require additional auxiliary sensors. Simulation results demonstrate that the proposed algorithm is effective and can precisely and comprehensively calibrate the errors in a .

Keywords： 双圈均匀圆阵；幅相误差；位置误差；互耦误差；校正    

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Joint compressed sensing imaging and phase adjustment via an iterative method for multistatic passive radar None

Jue WANG, Jun WANG

Frontiers of Information Technology & Electronic Engineering 2018, Volume 19, Issue 4,   Pages 557-568 doi: 10.1631/FITEE.1601423

Abstract: The resolution of the multistatic passive radar imaging system (MPRIS) is poor due to the narrow bandwidth of the signal transmitted by illuminators of opportunity. Moreover, the inaccuracies caused by the inaccurate tracking system or the error position measurement of illuminators or receivers can deteriorate the quality of an image. To improve the performance of an MPRIS, an imaging method based on the tomographic imaging principle is presented. Then the compressed sensing technique is extended to the MPRIS to realize high-resolution imaging. Furthermore, a phase correction technique is developed for compen-sating for phase errors in an MPRIS. Phase errors can be estimated by iteratively solving an equation that is derived by minimizing the mean recovery error of the reconstructed image based on the principle of fixed-point iteration technique. The technique is nonparametric and can be used to estimate phase errors of any form. The effectiveness and convergence of the technique are confirmed by numerical simulations.

Keywords： Multistatic passive radar     Compressed sensing     Phase adjustment     Fixed-point iteration technique    

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Error analysis and compensation of compound measuring system for blade surface

Li Bing,Chen Lei,Ding Jianjun,Jiang Zhuangde

Strategic Study of CAE 2013, Volume 15, Issue 1,   Pages 39-44

Abstract:

The high-accuracy measurement of complex airfoil surfaces is a critical issue in the inspection of blades. Aiming at this problem, a compound measuring principle is proposed in this paper. Using the principle, the airfoil surface and root datum of a blade are measured based on contact inductance method and non-contact laser triangular method, respectively. And a four-coordinate measuring system is designed and established. Then, on the basis of the mechanical structure of the measuring system, the geometric error of which is analyzed syste-matically. And a corresponding extraction and compensation method is proposed based on the laser interferometry. The experimental results show that the proposed error analysis and compensation methods can improve the accuracy of the four-coordinate measuring system effectively.

Keywords： blade airfoil surface     compound measuring principle     error analysis     error compensation     laser interferometry    

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Analysis on the Machined Surface Profile Error Using Fractals and Wavelet

Liao Xiaoyun,Tang Qian,Zhao Ying,Zheng Shize

Strategic Study of CAE 2002, Volume 4, Issue 5,   Pages 75-78

Abstract:

An analysis method based on fractals and wavelet for machined surface profile error was presented. It can be employed to analyze the machined surface in details, and reconstruct the surface profile for doing some related work, such as performance-tolerance analysis and process quality control. The fractal dimension algorithms, the analysis and reconstruction algorithms of surface profile based on wavelets theories were developed. The given example showed that this method and related algorithms were very effective.

Keywords： machining     machined error analysis     fractal geometry     wavelet analysis    

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Stepped frequency chirp signal imaging radar jamming using two-dimensional nonperiodic phase modulation Research Article

Qihua WU, Feng ZHAO, Tiehua ZHAO, Xiaobin LIU, Junjie WANG, Shunping XIAO

Frontiers of Information Technology & Electronic Engineering 2023, Volume 24, Issue 3,   Pages 433-446 doi: 10.1631/FITEE.2200298

Abstract: obtains high-resolution radar images by synthesizing multiple narrowband chirp pulses. It has been one of the most commonly used waveforms due to its lower demand for radar instant bandwidth. In this paper, we propose a method using two-dimensional against imaging radar. Using the unique property of , the proposed method can generate high-level sidelobes that perform as a special blanket jamming along both the range and azimuth directions and make the target unrecognizable. Then, the influence of different modulation parameters, such as the code width and duty ratio, are further discussed. Based on this, the corresponding parameter design principles are presented. Finally, the validity of the proposed method is demonstrated by the Yake-42 plane data simulation and measured unmanned aerial vehicle data experiment.

Keywords： Radar jamming     Stepped frequency chirp signal     Nonperiodic phase modulation     Wideband radar    

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HY-2A satellite radar altimeter error correction algorithm and verification

Zhang Youguan,Jia Yongjun,Fan Chenqing,Zhang Jie and Lin Mingsen

Strategic Study of CAE 2013, Volume 15, Issue 7,   Pages 53-61

Abstract:

There are many factors affecting the height accuracy of satillite radar altimeter. The dry troposphere delays, wet troposphere delays, invert barometer delays, ionosphere delays, and sea state bias influence the computational accuracy directly. The error correction algorithms for the HY-2A satellite radar altimeter were conducted in this research. And, these algorithms were vertified using the more mature foreign satellite data such as Jason-1/2 and T/P. The results show that the HY-2A error correction algorithms can meet the accuracy requirements.

Keywords： altimeter error correction     HY-2A satellite radar altimeter    

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The error adjusting method of lineshape control for the middle steel tower of Taizhou Bridge

Zhang Xiangqun,Wang Lin and You Xinpeng

Strategic Study of CAE 2012, Volume 14, Issue 5,   Pages 29-32

Abstract:

The middle tower of Taizhou Bridge is a steel frame with longitudinal herringbone shape and lateral gate shape, which is used for the first time. The technology with segments fabricated in the factory and erection at site is used in the construction of the middle steel tower. A full-procedure construction control system to the complicated tower is set up. Based on precise monitoring and control to the shape of the segments and the line-shape of the tower at the fabrication stage, the adjustment of the adjusting gap of the tower is calculated according to the actual error of the tower at the erection stage, and the line-shape error of the tower is adjusted. The result of the implementation of the middle steel tower of Taizhou Bridge indicated that the line-shape control method adapted could be effective, and the precision of final line-shape of the middle steel tower is better than that of the design requirements.

Keywords： Taizhou Bridge     middle steel tower     line shape control     error adjusting    

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Studies on Precise Spacecraft Navigation and Positioning Using GPS

Xiang Kaiheng,Qu Guangji

Strategic Study of CAE 2004, Volume 6, Issue 1,   Pages 86-91

Abstract:

In this paper, GPS measurement technology, Encke method to solve satellite orbit perturbation and generalized Kalman filtering technology are organically combined together, and an innovative solution— carrier phase & pseudorange integrated dynamic orbit determination (CPPIDOD) for low earth orbit spacecraft on-board autonomous precise navigation and positioning using GPS is presented. Difficult problems of dynamically resolving of integer ambiguities and amendment of cycle slips in the application of GPS carrier phase have been solved. Based on all these, technique of carrier phase & pseudorange integrated dynamic differential relative navigation between two spacecrafts is brought forward. Results of numerical simulation analyses and semi-physical simulation tests show that the solutions presented in this paper are feasible. They can significantly improve the performance of GPS positioning, and their models, algorithms and software are practical for engineering use.

Keywords： spacecraft     navigation     GPS     carrier phase     Kalman filtering    

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Title Author Date Type Operation

Effects of residual motion compensation errors on the performance of airborne along-track interferometric SAR

Hui ZHANG,Jun HONG,Xiao-lan QIU,Ji-chuan LI,Fang-fang LI,Feng MING

Journal Article

A general method of designing phase-shifting algorithms for grating lateral shearing interferometry

Chao FANG, Yang XIANG, Ke-qi QI

Journal Article

Virtual-position Reading Method—a Novel Method for Error Motion and Form Error Separation

Hong Maisheng,Li Zijun,Su Heng,Ye Feifan

Journal Article

Measurement and Information Technology

Zhang Guoxiong

Journal Article

Phase problems in optical imaging

Guo-hai SITU, Hai-chao WANG

Journal Article

Forward link outage performance of aeronautical broadband satellite communications

Huaicong Kong, Min Lin, Shiwen He, Xiaoyu Liu, Jian Ouyang, Weiping Zhu,linmin@njupt.edu.cn

Journal Article

A multi-functional dynamic state estimator for error validation: measurement and parameter errors and sudden load changes

Mehdi AHMADI JIRDEHI,Reza HEMMATI,Vahid ABBASI,Hedayat SABOORI

Journal Article

A comprehensive error calibration method based on dual uniform circular array

Jia-jia Zhang, Hui Chen, Song Xiao, Meng-yu Ni,zjj2015wuhan@163.com

Journal Article

Joint compressed sensing imaging and phase adjustment via an iterative method for multistatic passive radar

Jue WANG, Jun WANG

Journal Article

Error analysis and compensation of compound measuring system for blade surface

Li Bing,Chen Lei,Ding Jianjun,Jiang Zhuangde

Journal Article

Analysis on the Machined Surface Profile Error Using Fractals and Wavelet

Liao Xiaoyun,Tang Qian,Zhao Ying,Zheng Shize

Journal Article

Stepped frequency chirp signal imaging radar jamming using two-dimensional nonperiodic phase modulation

Qihua WU, Feng ZHAO, Tiehua ZHAO, Xiaobin LIU, Junjie WANG, Shunping XIAO

Journal Article

HY-2A satellite radar altimeter error correction algorithm and verification

Zhang Youguan,Jia Yongjun,Fan Chenqing,Zhang Jie and Lin Mingsen

Journal Article

The error adjusting method of lineshape control for the middle steel tower of Taizhou Bridge

Zhang Xiangqun,Wang Lin and You Xinpeng

Journal Article

Studies on Precise Spacecraft Navigation and Positioning Using GPS

Xiang Kaiheng,Qu Guangji

Journal Article