Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.Th...Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.This study introduces a composite denoising approach to address this challenge.This method is based on the ameliorated ellipse fitting algorithm(AEFA)and adaptive successive variational mode decomposition(ASVMD).This algorithm employs AEFA to eliminate system noise tightly coupled with direct-current and alternating-current components in the interference signal,thereby obtaining a phase signal containing only environmental noise.The ASVMD technique adaptively extracts environmental noise components predominantly present in the phase signal.To achieve optimal decomposition results automatically,the permutation entropy criterion is employed to refine decomposition parameters.The correlation coefficient is utilized to differentiate effective components from noise components in the decomposition results.Experimental results indicate that the combined AEFA and ASVMD algorithm effectively suppresses both system and environmental noises.When applied to 50 Hz vibration signal processing,the proposed approach achieves a noise reduction of 17.81 dB and a phase resolution of 35.14μrad/√Hz.Given the excellent performance of the noise suppression,the proposed approach holds great application potential in high-performance interferometric sensing systems.展开更多
Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predomina...Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predominantly on the phase-shifting approach,which involves collecting multiple interferograms and imposes stringent demands on environmental stability.These issues significantly hinder its ability to achieve real-time and dynamic high-precision measurements.Therefore,this study proposes a high-precision large-aperture single-frame interferometric surface profile measurement(LA-SFISPM)method based on deep learning and explores its capability to realize dynamic measurements with high accuracy.The interferogram is matched to the phase by training the data measured using the small aperture.The consistency of the surface features of the small and large apertures is enhanced via contrast learning and feature-distribution alignment.Hence,high-precision phase reconstruction of large-aperture optical components can be achieved without using a phase shifter.The experimental results show that for the tested mirror withΦ=820 mm,the surface profile obtained from LA-SFISPM is subtracted point-by-point from the ground truth,resulting in a maximum single-point error of 4.56 nm.Meanwhile,the peak-to-valley(PV)value is 0.0758λ,and the simple repeatability of root mean square(SR-RMS)value is 0.00025λ,which aligns well with the measured results obtained by ZYGO.In particular,a significant reduction in the measurement time(reduced by a factor of 48)is achieved compared with that of the traditional phase-shifting method.Our proposed method provides an efficient,rapid,and accurate method for obtaining the surface profiles of optical components with different diameters without employing a phase-shifting approach,which is highly desired in large-aperture interferometric measurement systems.展开更多
Quantum interferometric power(IP), a discordlike measure, plays an important role in quantum metrology. We study the dynamics of IP for two-qubit X-shape states under different noisy environments. Our study shows that...Quantum interferometric power(IP), a discordlike measure, plays an important role in quantum metrology. We study the dynamics of IP for two-qubit X-shape states under different noisy environments. Our study shows that IP exhibits sudden change, and one side quantum channel is enough for the occurrence of a sudden change of IP. In particular, we show that the initial state having no sudden change of quantum discord exhibits a sudden change of IP under the dynamics of amplitude noise, but the converse is not true. Besides, we also investigate the dynamics of IP under two different kinds of composite noises. Our results also confirm that sudden change of IP occurs under such composite noises.展开更多
This paper introduces a hybrid configuration design to enhance the precision of satellite antenna position measurement.By fixing the circular array antenna on the antenna mounting surface and integrating coordinate sy...This paper introduces a hybrid configuration design to enhance the precision of satellite antenna position measurement.By fixing the circular array antenna on the antenna mounting surface and integrating coordinate system transformation relationships with interferometric direction finding(DF)and positioning technology,accurate estimation of the antenna position is ensured.This method optimizes the quality and stability of data fusion by integrating pulse parameter characteristics,satellite orbit and attitude information,as well as the field of view information from observation stations,using techniques such as maximum-ratio-combining(MRC)and orbit extrapolation.Specifically,the sampling-importance resampling particle-filtering and Kalman-filtering(SIR-PF-KF)hybrid filtering prediction technology is employed to precisely predict and correct the three-dimensional(3D)position errors of the L-array antenna.Through data processing of five to nine orbits,accurate estimation of the antenna’s 3D position is achieved,achieving an estimation accuracy of 3μm,significantly improving the accuracy of on-orbit rapid calibration.Experimental results show that the interferometer positioning accuracy is improved from 7.9 km before antenna position correction to within 0.2 km after correction,verifying the effectiveness and practicability of this method,which aims to address issues with positioning accuracy.展开更多
Sea topography information holds significant importance in oceanic research and the climate change detection.Radar imaging altimetry has emerged as the leading approach for global ocean observation,employing synthetic...Sea topography information holds significant importance in oceanic research and the climate change detection.Radar imaging altimetry has emerged as the leading approach for global ocean observation,employing synthetic aperture radar(SAR)interferometry to enhance the spatial resolution of Sea topography.Nevertheless,current payload capacity and satellite hardware limitations prevent the extension of the interferometric baseline by enlarging the physical antenna size.This constraint hinders achieving centimeter-level accuracy in interferometric altimetry.To address this challenge,we conducted a numerical simulation to assess the viability of a large baseline interferometric imaging altimeter(LB-IIA).By controlling the baseline within the range of 600-1000 m through spiral orbit design in two satellites and mitigating baseline de-correlation with the carrier frequency shift(CFS)technique,we aimed to overcome the above limitations.Our findings demonstrate the efficacy of the CFS technique in compensating for baseline decoherence,elevating coherence from less than 0.1 to over 0.85.Concurrently.The height difference accuracy between neighboring sea surfaces reaches 1 cm within a 1 km resolution.This study is anticipated to serve as a foundational reference for future interferometric imaging altimeter development,catering to the demand for high-precision sea topography data in accurate global bathymetry inversion.展开更多
We proposed a fiber optic high temperature sensor based on the Mach-Zehnder interference(MZI)structure,which is composed of two lengths of multi-mode fibers(MMFs),a length of few-mode fiber(FMF)and two sections of sin...We proposed a fiber optic high temperature sensor based on the Mach-Zehnder interference(MZI)structure,which is composed of two lengths of multi-mode fibers(MMFs),a length of few-mode fiber(FMF)and two sections of single-mode fibers(SMFs).Firstly,the two sections of MMFs were spliced with two sections of SMFs.Then,the MMFs were fused to two ends of FMF to form a symmetrically structured fiber-optic MZI structure.In this structure,the MMF served as the optical mode field coupling element,and the cladding and core of the FMF are the interference arm and the reference arm of the MZI structure,respectively.We investigated the sensor's response characteristics of the temperature and strain.The experimental results indicate that the sensor is sensitive to temperature variation,and the temperature response sensitivity is up to 61.4 pm/℃ in the range of 40-250℃,while the sensor has weak strain sensitivity,its strain sensitivity is only-0.72 pm/μe in the strain range of 0-1400μe.Moreover,the sensor has good stability and repeatability.In brief,the proposed fiber optic high temperature sensor has good properties,such as high sensitivity,compact structure,good stability and repeatability,which can be used for monitoring the temperature of submerged oil electric pump units under oil wells.展开更多
The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is pe...The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is performed and the analytical equations describing the dependence of resolution on parameters of the interrogation setup are derived. The efficiency of the proposed signal processing approaches and the validity of analytical derivations are supported by experiments. The proposed approaches allow the interrogation of up to four multiplexed sensors with attained resolution between 30 pm and 80 pm, up to three times improvement of microdisplacement resolution of a single sensor by means of using the reference interferometer and noisecompensating approach, and ability to register signals with frequencies up to 1 kHz in the case of 1 Hz spectrum acquisition rate. The proposed approaches can be used for various applications, including biomedical, industrial inspection, and others, amongst the microdisplacement measurement.展开更多
High harmonic generation(HHG)provides an experimental method for producing attosecond pulses and probing electron dynamics.Achieving precise dipole phase measurements is critical for tailoring the harmonic emission ph...High harmonic generation(HHG)provides an experimental method for producing attosecond pulses and probing electron dynamics.Achieving precise dipole phase measurements is critical for tailoring the harmonic emission phase and identifying the HHG mechanism.However,achieving this feature by applying traditional two-beam far-field interferometry to solid materials remains challenging.In this study,we present a novel interferometric approach that utilizes a single laser beam to excite two ZnO microwires(MWs)simultaneously,thereby generating coherent high-harmonic sources that form interference fringes in the far-field region.We leverage the diameter-dependent field-enhancement effect in MWs to measure the intensity-dependent fringe shift,revealing that the intraband current mechanism dominates the below-bandgap harmonic,whereas the interband polarization mechanism dominates the above-bandgap harmonic.This study offers a robust method for measuring the dipole phase of solid-state HHG and inspires intensity-modulated high-harmonic applications in coherent imaging and microdevice design.展开更多
Knowledge of the locations of seismic sources is critical for microseismic monitoring. Time-window-based elastic wave interferometric imaging and weighted- elastic-wave （WEW） interferometric imaging are proposed and...Knowledge of the locations of seismic sources is critical for microseismic monitoring. Time-window-based elastic wave interferometric imaging and weighted- elastic-wave （WEW） interferometric imaging are proposed and used to locate modeled microseismic sources. The proposed method improves the precision and eliminates artifacts in location profiles. Numerical experiments based on a horizontally layered isotropic medium have shown that the method offers the following advantages： It can deal with Iow-SNR microseismic data with velocity perturbations as well as relatively sparse receivers and still maintain relatively high precision despite the errors in the velocity model. Furthermore, it is more efficient than conventional traveltime inversion methods because interferometric imaging does not require traveltime picking. Numerical results using a 2D fault model have also suggested that the weighted-elastic-wave interferometric imaging can locate multiple sources with higher location precision than the time-reverse imaging method.展开更多
The stability of submarine geological structures has a crucial influence on the construction of offshore engineering projects and the exploitation of seabed resources. Marine geologists should possess a detailed under...The stability of submarine geological structures has a crucial influence on the construction of offshore engineering projects and the exploitation of seabed resources. Marine geologists should possess a detailed understanding of common submarine geological hazards. Current marine seismic exploration methods are based on the most effective detection technologies. Therefore, current research focuses on improving the resolution and precision of shallow stratum structure detection methods. In this article, the feasibility of shallow seismic structure imaging is assessed by building a complex model, and differences between the seismic interferometry imaging method and the traditional imaging method are discussed. The imaging effect of the model is better for shallow layers than for deep layers because coherent noise produced by this method can result in an unsatisfactory imaging effect for deep layers. The seismic interference method has certain advantages for geological structural imaging of shallow submarine strata, which indicates continuous horizontal events, a high resolution, a clear fault, and an obvious structure boundary. The effects of the actual data applied to the Shenhu area can fully illustrate the advantages of the method. Thus, this method has the potential to provide new insights for shallow submarine strata imaging in the area.展开更多
Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scatteri...Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber. The phase noise structure is analyzed for an interferometric fiber sensing system, and an unbalanced Michelson interferometer with an optical path difference of 1 m, as well as the phase-generated carrier technique, is used to measure the phase noise. It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold, increases dramatically at first and then gradually becomes flat when the input power is above the threshold, which is similar to the variation in relative intensity noise. It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering, which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering.展开更多
The coherence is a measure for the accuracy of the interferometric phase, and the synthetic aperture radar （SAR） inter- ferometric coherence is affected by several sources of the decor- relation noise. For the circu...The coherence is a measure for the accuracy of the interferometric phase, and the synthetic aperture radar （SAR） inter- ferometric coherence is affected by several sources of the decor- relation noise. For the circular SAR （CSAR） imaging geometry, the system response function is in the form of the Bessel function which brings a high sidelobe, and the high sidelobe of CSAR will be an important factor influencing the interferometric coherence. The effect of the high sidelobe on the coherence is analyzed and deduced. Based on the interferometric characteristics of the slight difference in the viewing angles and the potential pixel off- set in the interferometric SAR （InSAR） images, a relation between the radar impulse response and the coherence loss function is derived. From the relational model, the coherence loss function due to the high sidelobe of CSAR is then deduced, and compared with that of the conventional SAR. It is shown that the high sidelobe of CSAR focusing signal will severely affect the baseline decorre- lation and coregistration decorrelation. Simulation results confirm the theoretical analysis and quantitatively show the baseline and coregistration decorrelation degradation due to the high sidelobes of CSAR.展开更多
In this paper, an algorithm of generating INSAR unwrapped phase image from SAR single-look complex images is presented. Besides the general processing technique, this article focuses on the methods of flat-earth phase...In this paper, an algorithm of generating INSAR unwrapped phase image from SAR single-look complex images is presented. Besides the general processing technique, this article focuses on the methods of flat-earth phase removal, phase noise reduction and phase unwrapping. The availability is tested by the results of processing ERS-1/2 SAR images.展开更多
Interferometric phase filtering is one of the key steps in interferometricsynthetic aperture radar (InSAR/SAR). However, the ideal filtering results are difficult toobtain due to dense fringe and low coherence regions...Interferometric phase filtering is one of the key steps in interferometricsynthetic aperture radar (InSAR/SAR). However, the ideal filtering results are difficult toobtain due to dense fringe and low coherence regions. Moreover, the InSAR/SAR datarange is relatively large, so the efficiency of interferential phase filtering is one of themajor problems. In this letter, we proposed an interferometric phase filtering methodbased on an amended matrix pencil and linear window mean filter. The combination ofthe matrix pencil and the linear mean filter are introduced to the interferometric phasefiltering for the first time. First, the interferometric signal is analyzed, and theinterferometric phase filtering is transformed into a local frequency estimation problem.Then, the local frequency is estimated using an amended matrix pencil at a window. Thelocal frequency can represent terrain changes, thus suggesting that the frequency can beaccurately estimated even in dense fringe regions. Finally, the local frequency is filteredby using a linear window mean filter, and the filtered phase is recovered. The proposedmethod is calculated by some matrices. Therefore, the computational complexity isreduced, and the efficiency of the interferometric phase filtering is improved.Experiments are conducted with simulated and real InSAR data. The proposed methodexhibits a better filtering effect and an ideal efficiency as compared with the traditionalfiltering method.展开更多
For the modified demodulation arithmetic of 3×3 coupler, the processing software built on the basis of Labview is able to demodulate asymmetric 3×3 coupler signal and do further spectrum analysis. It shows t...For the modified demodulation arithmetic of 3×3 coupler, the processing software built on the basis of Labview is able to demodulate asymmetric 3×3 coupler signal and do further spectrum analysis. It shows that the measured frequency ranges from 10 Hz to 1 000 Hz and phase range is covered by -10 rad^10 rad. The phase sensitivity is 0.5 V/rad. This system is proved to show high resolution and wide dynamic range.展开更多
Affected by the natural environmental and human activity factors,significant seasonal differences appear on the regional scattering characteristic and ground deformation of saline soil.Interferometric decorrelation du...Affected by the natural environmental and human activity factors,significant seasonal differences appear on the regional scattering characteristic and ground deformation of saline soil.Interferometric decorrelation due to season replacement limits the conventional multi-temporal interferometric synthetic aperture radar(MT-InSAR)technique and its application in such areas.To extend the monitoring capability in the salt desert area,we select a vast basin of saline soil around Howz-e-Soltan Salt Lake of Iran as the study area and present an improved MTInSAR for experimental research.Based on 131 C-band Sentinel-1 A images collected between October 2014 to July 2020,1896 refined interferograms in total are selected from all interferogram candidates.Interferometric coherence analysis shows that the coherence in the saline soil area has an apparent seasonal variation,and the soil moisture affected by the precipitation may be the main factor that leads to the seasonal variation.Subsequently,the deformation characteristics of saline soil under different environmental conditions and human activity factors are compared and analyzed in detail.Related deformation mechanisms of different saline soil types are initially revealed by combining interferometric coherence,meteorological data,and engineering geological characteristics of saline soil.Related results would provide reference for the large-scale infrastructure construction engineering in similar saline soil areas.展开更多
An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic...An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic crystal fiber(PCF)without cut-off wavelength is fused with a single-mode fiber(SMF),and the other end face of the PCF is coated with PCG sensing membrane.The collapsed layer formed during the air hole fusion of PCF is used as the first reflector,the interface between PCF and sensing membrane is used as the second reflector,and the interface between the sensing membrane and the air is used as the third reflector,thus the dual Fabry-Pe rot structure sensor is formed.The results show that the sensor has excellent sensitivity and selectivity to carbon monoxide.With the increasing concentration of carbon monoxide gas in the range of 0-60 ppm,the intensity of interference spectrum decreases.The sensitivity of the sensor is 0.3473 dB m/ppm,and its linearity is good.The response time and recovery time are 68 s and 106 s,respectively.The sensor has the advantages of the compact size,low cost,high sensitivity,strong selectivity and simple structure.It is suitable for the sensing detection of low concentration carbon monoxide gas.展开更多
We present a comprehensive set of physical and geometrical parameters for each of the components of the close visual binary system HIP 11253(HD 14874).We present an analysis for the binary and multiple stellar systems...We present a comprehensive set of physical and geometrical parameters for each of the components of the close visual binary system HIP 11253(HD 14874).We present an analysis for the binary and multiple stellar systems with the aim to obtain a match between the overall observational spectral energy distribution of the system and the spectral synthesis created from model atmospheres using Al-Wardat's method for analyzing binary and multiple stellar systems.The epoch positions are used to determine the orbital parameters and the total mass.The parameters of both components are derived as:T_(eff)^(a)=6025,T_(eff)^(b)=4710,logg_(a)=4.55,logg_(b)=4.60,R_(a)=1.125 R_(⊙),R_(b)=0.88R_(⊙),L_(a)=1.849 L_(⊙),L_(b)=0.342 L_(⊙).Our analysis shows that the spectral types of the components are F9 and K3.By combining the orbital solution with the parallax measurements of Gaia DR2 and EDR3,we estimate the individual masses using the H-R diagram as M_(a)=1.09 M_(⊙)and M_(b)=0.59 M_(⊙)for using Gaia DR2 parallax and M_(a)=1.10 M_(⊙)and M_(b)=0.61 M_(⊙)for using Gaia EDR3 parallax.Finally,the location of both system's components on the stellar evolutionary tracks is presented.展开更多
Tests of preoperative visual function and prediction of postoperative E chart visual acuity(ECVA) using laser interferometric visual acuity(LIVA) and electroretinogram(ERG) were performed in 16 cases(19 eyes) of catar...Tests of preoperative visual function and prediction of postoperative E chart visual acuity(ECVA) using laser interferometric visual acuity(LIVA) and electroretinogram(ERG) were performed in 16 cases(19 eyes) of cataract. The results showed that the coincident rate between preoperative LIVA and postoperative ECVA was 63.2%, and there was a parallel correlation between preoperative amplitude of photopic ERG b-wave and postoperative ECVA in 79.0% of the eyes. Comparing these two methods, the test of LIVA ...展开更多
An approach based on interferometry technique is proposed for three-dimensional （3D） bistatic inverse synthetic aperture radar （ISAR） imaging. It is converted to a monostatic problem by using the theory that a bis...An approach based on interferometry technique is proposed for three-dimensional （3D） bistatic inverse synthetic aperture radar （ISAR） imaging. It is converted to a monostatic problem by using the theory that a bistatic radar equals a monostatic radar located on the bisector of bistatic an- gle. Then, interferometric phases extracted from a pair of cross shaped antennas are used to esti- mate the height and associated rotational velocity. Finally, numerical simulations are provided to e- valuate this method.展开更多
文摘Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.This study introduces a composite denoising approach to address this challenge.This method is based on the ameliorated ellipse fitting algorithm(AEFA)and adaptive successive variational mode decomposition(ASVMD).This algorithm employs AEFA to eliminate system noise tightly coupled with direct-current and alternating-current components in the interference signal,thereby obtaining a phase signal containing only environmental noise.The ASVMD technique adaptively extracts environmental noise components predominantly present in the phase signal.To achieve optimal decomposition results automatically,the permutation entropy criterion is employed to refine decomposition parameters.The correlation coefficient is utilized to differentiate effective components from noise components in the decomposition results.Experimental results indicate that the combined AEFA and ASVMD algorithm effectively suppresses both system and environmental noises.When applied to 50 Hz vibration signal processing,the proposed approach achieves a noise reduction of 17.81 dB and a phase resolution of 35.14μrad/√Hz.Given the excellent performance of the noise suppression,the proposed approach holds great application potential in high-performance interferometric sensing systems.
基金funded by the National Natural Science Foundation of China Instrumentation Program(52327806)Youth Fund of the National Nature Foundation of China(62405020)China Postdoctoral Science Foundation(2024M764131).
文摘Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predominantly on the phase-shifting approach,which involves collecting multiple interferograms and imposes stringent demands on environmental stability.These issues significantly hinder its ability to achieve real-time and dynamic high-precision measurements.Therefore,this study proposes a high-precision large-aperture single-frame interferometric surface profile measurement(LA-SFISPM)method based on deep learning and explores its capability to realize dynamic measurements with high accuracy.The interferogram is matched to the phase by training the data measured using the small aperture.The consistency of the surface features of the small and large apertures is enhanced via contrast learning and feature-distribution alignment.Hence,high-precision phase reconstruction of large-aperture optical components can be achieved without using a phase shifter.The experimental results show that for the tested mirror withΦ=820 mm,the surface profile obtained from LA-SFISPM is subtracted point-by-point from the ground truth,resulting in a maximum single-point error of 4.56 nm.Meanwhile,the peak-to-valley(PV)value is 0.0758λ,and the simple repeatability of root mean square(SR-RMS)value is 0.00025λ,which aligns well with the measured results obtained by ZYGO.In particular,a significant reduction in the measurement time(reduced by a factor of 48)is achieved compared with that of the traditional phase-shifting method.Our proposed method provides an efficient,rapid,and accurate method for obtaining the surface profiles of optical components with different diameters without employing a phase-shifting approach,which is highly desired in large-aperture interferometric measurement systems.
基金Project supported by the National Natural Science Foundations of China (Grant Nos. 11675119,12275136,and 12075001)the Nankai Zhide Foundations。
文摘Quantum interferometric power(IP), a discordlike measure, plays an important role in quantum metrology. We study the dynamics of IP for two-qubit X-shape states under different noisy environments. Our study shows that IP exhibits sudden change, and one side quantum channel is enough for the occurrence of a sudden change of IP. In particular, we show that the initial state having no sudden change of quantum discord exhibits a sudden change of IP under the dynamics of amplitude noise, but the converse is not true. Besides, we also investigate the dynamics of IP under two different kinds of composite noises. Our results also confirm that sudden change of IP occurs under such composite noises.
文摘This paper introduces a hybrid configuration design to enhance the precision of satellite antenna position measurement.By fixing the circular array antenna on the antenna mounting surface and integrating coordinate system transformation relationships with interferometric direction finding(DF)and positioning technology,accurate estimation of the antenna position is ensured.This method optimizes the quality and stability of data fusion by integrating pulse parameter characteristics,satellite orbit and attitude information,as well as the field of view information from observation stations,using techniques such as maximum-ratio-combining(MRC)and orbit extrapolation.Specifically,the sampling-importance resampling particle-filtering and Kalman-filtering(SIR-PF-KF)hybrid filtering prediction technology is employed to precisely predict and correct the three-dimensional(3D)position errors of the L-array antenna.Through data processing of five to nine orbits,accurate estimation of the antenna’s 3D position is achieved,achieving an estimation accuracy of 3μm,significantly improving the accuracy of on-orbit rapid calibration.Experimental results show that the interferometer positioning accuracy is improved from 7.9 km before antenna position correction to within 0.2 km after correction,verifying the effectiveness and practicability of this method,which aims to address issues with positioning accuracy.
文摘Sea topography information holds significant importance in oceanic research and the climate change detection.Radar imaging altimetry has emerged as the leading approach for global ocean observation,employing synthetic aperture radar(SAR)interferometry to enhance the spatial resolution of Sea topography.Nevertheless,current payload capacity and satellite hardware limitations prevent the extension of the interferometric baseline by enlarging the physical antenna size.This constraint hinders achieving centimeter-level accuracy in interferometric altimetry.To address this challenge,we conducted a numerical simulation to assess the viability of a large baseline interferometric imaging altimeter(LB-IIA).By controlling the baseline within the range of 600-1000 m through spiral orbit design in two satellites and mitigating baseline de-correlation with the carrier frequency shift(CFS)technique,we aimed to overcome the above limitations.Our findings demonstrate the efficacy of the CFS technique in compensating for baseline decoherence,elevating coherence from less than 0.1 to over 0.85.Concurrently.The height difference accuracy between neighboring sea surfaces reaches 1 cm within a 1 km resolution.This study is anticipated to serve as a foundational reference for future interferometric imaging altimeter development,catering to the demand for high-precision sea topography data in accurate global bathymetry inversion.
基金supported by the Scientific Research Program Funded by Shaanxi Provincial Education Department (No.15JK1573)the Postgraduate Innovation and Practice Ability Development Fund of Xi’an Shiyou University (No.YCS21211084)。
文摘We proposed a fiber optic high temperature sensor based on the Mach-Zehnder interference(MZI)structure,which is composed of two lengths of multi-mode fibers(MMFs),a length of few-mode fiber(FMF)and two sections of single-mode fibers(SMFs).Firstly,the two sections of MMFs were spliced with two sections of SMFs.Then,the MMFs were fused to two ends of FMF to form a symmetrically structured fiber-optic MZI structure.In this structure,the MMF served as the optical mode field coupling element,and the cladding and core of the FMF are the interference arm and the reference arm of the MZI structure,respectively.We investigated the sensor's response characteristics of the temperature and strain.The experimental results indicate that the sensor is sensitive to temperature variation,and the temperature response sensitivity is up to 61.4 pm/℃ in the range of 40-250℃,while the sensor has weak strain sensitivity,its strain sensitivity is only-0.72 pm/μe in the strain range of 0-1400μe.Moreover,the sensor has good stability and repeatability.In brief,the proposed fiber optic high temperature sensor has good properties,such as high sensitivity,compact structure,good stability and repeatability,which can be used for monitoring the temperature of submerged oil electric pump units under oil wells.
文摘The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is performed and the analytical equations describing the dependence of resolution on parameters of the interrogation setup are derived. The efficiency of the proposed signal processing approaches and the validity of analytical derivations are supported by experiments. The proposed approaches allow the interrogation of up to four multiplexed sensors with attained resolution between 30 pm and 80 pm, up to three times improvement of microdisplacement resolution of a single sensor by means of using the reference interferometer and noisecompensating approach, and ability to register signals with frequencies up to 1 kHz in the case of 1 Hz spectrum acquisition rate. The proposed approaches can be used for various applications, including biomedical, industrial inspection, and others, amongst the microdisplacement measurement.
基金supported by the National Key R&D Program of China (Grant Nos.2023YFA1406801 and 2022YFA1604301)the National Natural Science Foundation of China (Grant Nos.12434013,12595343,12404393,and 12174011)。
文摘High harmonic generation(HHG)provides an experimental method for producing attosecond pulses and probing electron dynamics.Achieving precise dipole phase measurements is critical for tailoring the harmonic emission phase and identifying the HHG mechanism.However,achieving this feature by applying traditional two-beam far-field interferometry to solid materials remains challenging.In this study,we present a novel interferometric approach that utilizes a single laser beam to excite two ZnO microwires(MWs)simultaneously,thereby generating coherent high-harmonic sources that form interference fringes in the far-field region.We leverage the diameter-dependent field-enhancement effect in MWs to measure the intensity-dependent fringe shift,revealing that the intraband current mechanism dominates the below-bandgap harmonic,whereas the interband polarization mechanism dominates the above-bandgap harmonic.This study offers a robust method for measuring the dipole phase of solid-state HHG and inspires intensity-modulated high-harmonic applications in coherent imaging and microdevice design.
基金supported by the R&D of Key Instruments and Technologies for Deep Resources Prospecting(No.ZDYZ2012-1)National Natural Science Foundation of China(No.11374322)
文摘Knowledge of the locations of seismic sources is critical for microseismic monitoring. Time-window-based elastic wave interferometric imaging and weighted- elastic-wave （WEW） interferometric imaging are proposed and used to locate modeled microseismic sources. The proposed method improves the precision and eliminates artifacts in location profiles. Numerical experiments based on a horizontally layered isotropic medium have shown that the method offers the following advantages： It can deal with Iow-SNR microseismic data with velocity perturbations as well as relatively sparse receivers and still maintain relatively high precision despite the errors in the velocity model. Furthermore, it is more efficient than conventional traveltime inversion methods because interferometric imaging does not require traveltime picking. Numerical results using a 2D fault model have also suggested that the weighted-elastic-wave interferometric imaging can locate multiple sources with higher location precision than the time-reverse imaging method.
基金supported by the National Natural Science Foundation of China (Nos. 41230318, 41176077, 4130 4096)the National High-tech R&D Program of China (863) (No. 2013AA092501)+2 种基金the PhD Program Foundation of the Ministry of Education of China (No. 201301 32120014)the Fundamental Research Funds for the Central Universities (Nos. 1313017, 1362013)Major National Science and Technology Programs (No. 2016ZX 05024-001-002)
文摘The stability of submarine geological structures has a crucial influence on the construction of offshore engineering projects and the exploitation of seabed resources. Marine geologists should possess a detailed understanding of common submarine geological hazards. Current marine seismic exploration methods are based on the most effective detection technologies. Therefore, current research focuses on improving the resolution and precision of shallow stratum structure detection methods. In this article, the feasibility of shallow seismic structure imaging is assessed by building a complex model, and differences between the seismic interferometry imaging method and the traditional imaging method are discussed. The imaging effect of the model is better for shallow layers than for deep layers because coherent noise produced by this method can result in an unsatisfactory imaging effect for deep layers. The seismic interference method has certain advantages for geological structural imaging of shallow submarine strata, which indicates continuous horizontal events, a high resolution, a clear fault, and an obvious structure boundary. The effects of the actual data applied to the Shenhu area can fully illustrate the advantages of the method. Thus, this method has the potential to provide new insights for shallow submarine strata imaging in the area.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61177073)the Open Fund of Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Jinan University, China (Grant No. gdol201101)+1 种基金the Fund of Innovation of Graduate School of NUDT, China (Grant No. B110703)Hunan Provincial Innovation Foundation for Postgraduate,China (Grant No. CX2011B033)
文摘Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber. The phase noise structure is analyzed for an interferometric fiber sensing system, and an unbalanced Michelson interferometer with an optical path difference of 1 m, as well as the phase-generated carrier technique, is used to measure the phase noise. It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold, increases dramatically at first and then gradually becomes flat when the input power is above the threshold, which is similar to the variation in relative intensity noise. It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering, which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The coherence is a measure for the accuracy of the interferometric phase, and the synthetic aperture radar （SAR） inter- ferometric coherence is affected by several sources of the decor- relation noise. For the circular SAR （CSAR） imaging geometry, the system response function is in the form of the Bessel function which brings a high sidelobe, and the high sidelobe of CSAR will be an important factor influencing the interferometric coherence. The effect of the high sidelobe on the coherence is analyzed and deduced. Based on the interferometric characteristics of the slight difference in the viewing angles and the potential pixel off- set in the interferometric SAR （InSAR） images, a relation between the radar impulse response and the coherence loss function is derived. From the relational model, the coherence loss function due to the high sidelobe of CSAR is then deduced, and compared with that of the conventional SAR. It is shown that the high sidelobe of CSAR focusing signal will severely affect the baseline decorre- lation and coregistration decorrelation. Simulation results confirm the theoretical analysis and quantitatively show the baseline and coregistration decorrelation degradation due to the high sidelobes of CSAR.
文摘In this paper, an algorithm of generating INSAR unwrapped phase image from SAR single-look complex images is presented. Besides the general processing technique, this article focuses on the methods of flat-earth phase removal, phase noise reduction and phase unwrapping. The availability is tested by the results of processing ERS-1/2 SAR images.
基金The authors would like to thank the support by the State Key Program of National Natural Science Foundation of China under Grant[Number 41774026]the Satellite Mapping Technology and Application,National Administration of Surveying,Mapping and Geoinformation Key Laboratory under Grant[Number KLSMTA-201708].
文摘Interferometric phase filtering is one of the key steps in interferometricsynthetic aperture radar (InSAR/SAR). However, the ideal filtering results are difficult toobtain due to dense fringe and low coherence regions. Moreover, the InSAR/SAR datarange is relatively large, so the efficiency of interferential phase filtering is one of themajor problems. In this letter, we proposed an interferometric phase filtering methodbased on an amended matrix pencil and linear window mean filter. The combination ofthe matrix pencil and the linear mean filter are introduced to the interferometric phasefiltering for the first time. First, the interferometric signal is analyzed, and theinterferometric phase filtering is transformed into a local frequency estimation problem.Then, the local frequency is estimated using an amended matrix pencil at a window. Thelocal frequency can represent terrain changes, thus suggesting that the frequency can beaccurately estimated even in dense fringe regions. Finally, the local frequency is filteredby using a linear window mean filter, and the filtered phase is recovered. The proposedmethod is calculated by some matrices. Therefore, the computational complexity isreduced, and the efficiency of the interferometric phase filtering is improved.Experiments are conducted with simulated and real InSAR data. The proposed methodexhibits a better filtering effect and an ideal efficiency as compared with the traditionalfiltering method.
文摘For the modified demodulation arithmetic of 3×3 coupler, the processing software built on the basis of Labview is able to demodulate asymmetric 3×3 coupler signal and do further spectrum analysis. It shows that the measured frequency ranges from 10 Hz to 1 000 Hz and phase range is covered by -10 rad^10 rad. The phase sensitivity is 0.5 V/rad. This system is proved to show high resolution and wide dynamic range.
基金supported by the National Natural Science Foundation of China(41771402,41804009)the National Key R&D Program of China(2017YFB0502700)Sichuan Science and Technology Program(2018JY0564,2019ZDZX0042,2020JDTD0003)。
文摘Affected by the natural environmental and human activity factors,significant seasonal differences appear on the regional scattering characteristic and ground deformation of saline soil.Interferometric decorrelation due to season replacement limits the conventional multi-temporal interferometric synthetic aperture radar(MT-InSAR)technique and its application in such areas.To extend the monitoring capability in the salt desert area,we select a vast basin of saline soil around Howz-e-Soltan Salt Lake of Iran as the study area and present an improved MTInSAR for experimental research.Based on 131 C-band Sentinel-1 A images collected between October 2014 to July 2020,1896 refined interferograms in total are selected from all interferogram candidates.Interferometric coherence analysis shows that the coherence in the saline soil area has an apparent seasonal variation,and the soil moisture affected by the precipitation may be the main factor that leads to the seasonal variation.Subsequently,the deformation characteristics of saline soil under different environmental conditions and human activity factors are compared and analyzed in detail.Related deformation mechanisms of different saline soil types are initially revealed by combining interferometric coherence,meteorological data,and engineering geological characteristics of saline soil.Related results would provide reference for the large-scale infrastructure construction engineering in similar saline soil areas.
基金supported by the National Natural Science Foundation of China(No.51574054)the University Innovation Team Building Program of Chongqing(No.CXTDX201601030)+2 种基金Scientific and Technological Research Program of Chongqing Municipal Education Commission(No.KJZD-M201901102)Chongqing Science and Technology Bureau(Nos.cstc2017shmsA20017,cstc2018jcyjAX0294,CSTCCXLJRC 201905)the Innovation Leader Project of Chongqing Science and Technology Bureau(No.CSTCCXLJRC201905)。
文摘An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic crystal fiber(PCF)without cut-off wavelength is fused with a single-mode fiber(SMF),and the other end face of the PCF is coated with PCG sensing membrane.The collapsed layer formed during the air hole fusion of PCF is used as the first reflector,the interface between PCF and sensing membrane is used as the second reflector,and the interface between the sensing membrane and the air is used as the third reflector,thus the dual Fabry-Pe rot structure sensor is formed.The results show that the sensor has excellent sensitivity and selectivity to carbon monoxide.With the increasing concentration of carbon monoxide gas in the range of 0-60 ppm,the intensity of interference spectrum decreases.The sensitivity of the sensor is 0.3473 dB m/ppm,and its linearity is good.The response time and recovery time are 68 s and 106 s,respectively.The sensor has the advantages of the compact size,low cost,high sensitivity,strong selectivity and simple structure.It is suitable for the sensing detection of low concentration carbon monoxide gas.
文摘We present a comprehensive set of physical and geometrical parameters for each of the components of the close visual binary system HIP 11253(HD 14874).We present an analysis for the binary and multiple stellar systems with the aim to obtain a match between the overall observational spectral energy distribution of the system and the spectral synthesis created from model atmospheres using Al-Wardat's method for analyzing binary and multiple stellar systems.The epoch positions are used to determine the orbital parameters and the total mass.The parameters of both components are derived as:T_(eff)^(a)=6025,T_(eff)^(b)=4710,logg_(a)=4.55,logg_(b)=4.60,R_(a)=1.125 R_(⊙),R_(b)=0.88R_(⊙),L_(a)=1.849 L_(⊙),L_(b)=0.342 L_(⊙).Our analysis shows that the spectral types of the components are F9 and K3.By combining the orbital solution with the parallax measurements of Gaia DR2 and EDR3,we estimate the individual masses using the H-R diagram as M_(a)=1.09 M_(⊙)and M_(b)=0.59 M_(⊙)for using Gaia DR2 parallax and M_(a)=1.10 M_(⊙)and M_(b)=0.61 M_(⊙)for using Gaia EDR3 parallax.Finally,the location of both system's components on the stellar evolutionary tracks is presented.
文摘Tests of preoperative visual function and prediction of postoperative E chart visual acuity(ECVA) using laser interferometric visual acuity(LIVA) and electroretinogram(ERG) were performed in 16 cases(19 eyes) of cataract. The results showed that the coincident rate between preoperative LIVA and postoperative ECVA was 63.2%, and there was a parallel correlation between preoperative amplitude of photopic ERG b-wave and postoperative ECVA in 79.0% of the eyes. Comparing these two methods, the test of LIVA ...
文摘An approach based on interferometry technique is proposed for three-dimensional （3D） bistatic inverse synthetic aperture radar （ISAR） imaging. It is converted to a monostatic problem by using the theory that a bistatic radar equals a monostatic radar located on the bisector of bistatic an- gle. Then, interferometric phases extracted from a pair of cross shaped antennas are used to esti- mate the height and associated rotational velocity. Finally, numerical simulations are provided to e- valuate this method.
