- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Geometry error analysis in solar Doppler difference navigation for the capture phase
摘要： Deep space exploration missions continue to become more ambitious, driving the need to investigate autonomous navigation systems that are accurate and timely. The solar Doppler difference navigation is a newly-developed and promising celestial autonomous navigation method for use, particularly in the crucial capture period. In this paper, we present novel analyses for three error sources for the solar Doppler difference navigation from the perspective of geometry, motivated with a Mars Deep Space Exploration example. The geometry error sources include the area overlap rate of the direct and the reflected solar light sources, the spread effects related to the time difference of arrival (TDOA) of light, and the solar rotation Doppler difference error. The area overlap rate and the spread effects of TDOA can be utilized to assess the overlap degree of the direct source and the reflected source in both space and time. Theoretical analyses and simulation results demonstrate that the direct and the reflected light sources can be accurately approximated as the same source. The solar rotation Doppler difference error is explored using a velocity error model. This model forms a hemi-ellipsoid that can be utilized to compensate the Doppler error caused by the solar rotation. The three errors decline with the deep space explorer approaching Mars, which means that the performance of the solar Doppler difference navigation method continuously improves in the critical capture period. These results can offer a reference for the system design of the solar Doppler difference navigation.
关键词： error analysis,solar spectrum,Doppler effects,navigation,geometry error
更新于2025-09-23 15:22:29
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[IEEE 2018 9th International Conference on Mechanical and Aerospace Engineering (ICMAE) - Budapest (2018.7.10-2018.7.13)] 2018 9th International Conference on Mechanical and Aerospace Engineering (ICMAE) - Resident Space Objects Streak Extraction and Angular Measurement Error Analysis Base on Space Image Synthesis System
摘要： To maintain awareness, space development of space-based visible system has gained much attention in recent years. Because the angular measurement accuracy of space-based sensor is very sensitive to orbit determination, it’s necessary to analyze the factors of angular measurement error, which can provide references for optimal design of space-based sensor. In this paper, a space image synthesis system is developed to provide the image source for resident space object detection and extraction. Then image extraction error and pose error of observation platform are analyzed, with which that the angle measurement error decreases as the focal length and size of pixel increase under same image extraction error can be concluded. Compared with position and velocity error of satellite, attitude angle error has greater impact on angle measurement error of RSOs. By using Otsu method and mathematical morphology method, the angle measurement error of RSOs can be controlled within 7 arcseconds.
关键词： resident space object,error analysis,angular measurement,space situational awareness,space image synthesis
更新于2025-09-23 15:22:29
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Study on the measurement error and scope of analytical gradient model in phase measuring deflectometry
摘要： The existing analytical gradient models in phase measuring de?ectometry (PMD) usually su?er in the ambiguous problem. To solve this problem, simpli?cation/assumption is often given to the surface shape, which causes non-ignorable measurement error in certain situations. In order to analyze the relation between the surface shape and measurement error when simpli?cation/assumption is used, a ray tracing simulation model is developed in this paper. For any given PMD system setup, the relation between the height/slope variations of test surface and measurement accuracy can be carried out. The corresponding experiment work proves the correctness of this simulation model. The increasing of either the height or slope of object will lead to the exponential aggravating of measurement error. For our experiment setup, the measurement gradient error will be less than 0.5% if the ratio of the distance between the LCD (Liquid Crystal Display) screen and the reference plane and the STD (standard derivation) of object height is larger than 200.
关键词： Phase measuring de?ectometry,Error analysis,Ray tracing model,Optical 3D measurement
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Quantitative optical assessment of electronic and photonic properties
摘要： In this paper, a discrete version of weighted centroid localization algorithm (dWCL) is proposed for a wireless-sensor-network-based indoor positioning system. Under this architecture, a wireless device can estimate its own position based on the location information of connected wireless sensor nodes in the network. Unlike other weighted centroid localization algorithms, dWCL classifies the sensor nodes into a number of groups and assigns them weights taken from a set of discrete values. With the weighting function and the range information decoupled, the dWCL framework is flexible to adjust its performance in accordance with the requirements. Its capability to generalize some existing weighted centroid localization algorithms is also demonstrated. In addition, the performance of dWCL is characterized by the error distribution in terms of accuracy and precision. Further enhancement is achieved by optimizing the system parameters. Finally, the simulation results are presented to validate the proposed scheme and analytical framework.
关键词： optimization,indoor positioning systems,Weighted centroid localization,wireless sensor network,error analysis
更新于2025-09-23 15:19:57
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Optical Coherence Tomography/Angiography-Guided Tumor Ablation With a Continuous-Wave Laser Diode
摘要： A conventional interferometric synthetic aperture radar (SAR) system provides 1-D line-of-sight motion measurements from repeat-pass observations. Two-dimensional motions may be measured by combining two observations from ascending and descending geometries. The third motion component may be retrieved by adding a third geometry and/or by integrating along-track measurements although with much reduced precision compared to the other two components. Several options exist to improve the accuracy of retrieving the third motion component, such as combining left- and right-looking observations or exploiting recently proposed innovative SAR acquisition modes (BiDiSAR and SuperSAR). These options are, however, challenging for future SAR systems based on large reflector antennae, due to lack of capability to electronic beam steering or frequent toggle between left- and right-looking modes. Therefore, in this letter, we assess and compare the realistic acquisition scenarios for a reflector-based SAR in an attempt to optimize the achievable 3-D precision. Investigating the squinted SAR geometry as one of the feasible scenarios, we show that a squint of 13.5? will yield comparable performance to the left-looking acquisition, while further squinting outperforms this or other feasible configurations. As an optimum configuration for 3-D retrieval, the squinted acquisition is further elaborated: the different acquisition plans considering a constellation of two satellites as well as the challenges for data processing are addressed.
关键词： squinted SAR,3-D surface motion,error analysis,interferometric SAR (InSAR),Azimuth shifts,SAR acquisition geometry
更新于2025-09-23 15:19:57
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Translating Radiometric Requirements for Satellite Sensors to Match International Standards
摘要： International scientific standards organizations created standards on evaluating uncertainty in the early 1990s. Although scientists from many fields use these standards, they are not consistently implemented in the remote sensing community, where traditional error analysis framework persists. For a satellite instrument under development, this can create confusion in showing whether requirements are met. We aim to create a methodology for translating requirements from the error analysis framework to the modern uncertainty approach using the product level requirements of the Advanced Baseline Imager (ABI) that will fly on the Geostationary Operational Environmental Satellite R-Series (GOES-R). In this paper we prescribe a method to combine several measurement performance requirements, written using a traditional error analysis framework, into a single specification using the propagation of uncertainties formula. By using this approach, scientists can communicate requirements in a consistent uncertainty framework leading to uniform interpretation throughout the development and operation of any satellite instrument.
关键词： satellite sensor uncertainty requirements,ISO standards,Guide to the Expression of Uncertainty in Measurement (GUM),GOES-R Advanced Baseline Imager,error analysis
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - A Novel Approach to Amine-Thiol Molecular Precursors for Fabrication of High Efficiency Thin Film CISSe/CIGSSe Devices
摘要： 3-D coordinate transformation, which is based on aligning two sets of common reference points, is frequently applied in large-scale combined measurement to unify coordinate frames and tie individual measurement systems together. However, it introduces uncertainty into the ?nal measurement results. This uncertainty must be quanti?ed to make the results complete. This paper presents a novel approach to the uncertainty analysis of 3-D coordinate transformation based on the weighted total least squares adjustment. This approach takes full account of the uncertainty characteristics of measuring instruments and is simple in calculation. In this approach, the transformation uncertainty of a point in a world frame is analyzed carefully. The simulations show that the transformation uncertainty has a distribution of concentric ellipsoids and is affected by the measurement uncertainties and layout of common points. Besides, strategies for minimizing transformation uncertainty are recommended. The experimental results from a laser tracker prove that this proposed approach is valid under normal instrument operating conditions and that these strategies are feasible and ef?cient.
关键词： Coordinate transformation,error analysis,uncertainty,large-scale metrology,position measurement,sensor fusion
更新于2025-09-19 17:13:59
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Modeling and analysis for the position and posture errors of laser focal spot in large-scale fabrication via two photon polymerization
摘要： The position and posture errors of laser focal spot significantly affect the fabrication quality and functionality of microstructures in two photon polymerization, especially over a large area. These errors can be greatly reduced by using ultra-precision positioning device, such as piezoelectric stage and scanning galvanometer. However, the position and posture errors cannot be neglected in large-scale fabrication using large stroke linear stages which are necessary tools in most instances. In the present work, the relationship between the geometric errors of large stroke positioning platform and the position and posture of laser focal spot were revealed and modeled by homogeneous transformation matrix. Key errors affecting on the position and posture of focal spot were found out by sensitivity analysis and compensated during the construction of machine tool. Proof-of-concept experiments were performed in a millimeter-level (1 mm × 1 mm) fabrication of microfluidic whose surface was measured by an optical profiler. The measuring results showed that arithmetical mean height (Sa) and root mean square height (Sq) of the measured surface were less than 100 nm and maximum height (Sz) of the measured surface was less than 500 nm. The compensated machine tool demonstrated a high precise performance within a large continuous area. This work was expected to provide references for the rational layout of optical components in optical system or error compensation in laser process equipment over a large area.
关键词： Laser beam delivery,Position and posture error,Error analysis,Large-scale fabrication,Two photon polymerization
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Delta-doping for enhanced tunnel junction performance and thermal stability
摘要： A conventional interferometric synthetic aperture radar (SAR) system provides 1-D line-of-sight motion measurements from repeat-pass observations. Two-dimensional motions may be measured by combining two observations from ascending and descending geometries. The third motion component may be retrieved by adding a third geometry and/or by integrating along-track measurements although with much reduced precision compared to the other two components. Several options exist to improve the accuracy of retrieving the third motion component, such as combining left- and right-looking observations or exploiting recently proposed innovative SAR acquisition modes (BiDiSAR and SuperSAR). These options are, however, challenging for future SAR systems based on large reflector antennae, due to lack of capability to electronic beam steering or frequent toggle between left- and right-looking modes. Therefore, in this letter, we assess and compare the realistic acquisition scenarios for a reflector-based SAR in an attempt to optimize the achievable 3-D precision. Investigating the squinted SAR geometry as one of the feasible scenarios, we show that a squint of 13.5? will yield comparable performance to the left-looking acquisition, while further squinting outperforms this or other feasible configurations. As an optimum configuration for 3-D retrieval, the squinted acquisition is further elaborated: the different acquisition plans considering a constellation of two satellites as well as the challenges for data processing are addressed.
关键词： squinted SAR,3-D surface motion,error analysis,interferometric SAR (InSAR),Azimuth shifts,SAR acquisition geometry
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Dual-band tunable mid-infrared polarization converter based on U-shaped graphene metamaterial
摘要： 3-D coordinate transformation, which is based on aligning two sets of common reference points, is frequently applied in large-scale combined measurement to unify coordinate frames and tie individual measurement systems together. However, it introduces uncertainty into the ?nal measurement results. This uncertainty must be quanti?ed to make the results complete. This paper presents a novel approach to the uncertainty analysis of 3-D coordinate transformation based on the weighted total least squares adjustment. This approach takes full account of the uncertainty characteristics of measuring instruments and is simple in calculation. In this approach, the transformation uncertainty of a point in a world frame is analyzed carefully. The simulations show that the transformation uncertainty has a distribution of concentric ellipsoids and is affected by the measurement uncertainties and layout of common points. Besides, strategies for minimizing transformation uncertainty are recommended. The experimental results from a laser tracker prove that this proposed approach is valid under normal instrument operating conditions and that these strategies are feasible and ef?cient.
关键词： Coordinate transformation,error analysis,uncertainty,large-scale metrology,position measurement,sensor fusion
更新于2025-09-16 10:30:52