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LU Zuliang, YANG Yan, ZHANG Zhonghua
2025,45(5):1-9 ,DOI: 10.11823/j.issn.1674-5795.2025.05.01
Abstract:
To accurately achieve the desired phase angle during digital-to-analog conversion, a commonly used approach is to increase the conversion resolution. This method relies on finer amplitude-axis discretization to better approximate the original waveform. However, it comes with several disadvantages, such as high cost, slow conversion speed, and considerable power consumption. To solve these problems, this paper further explores a novel method — time-axis segmentation. A definition of quantization error is introduced, which includes both phase angle quantization error (PQE) and amplitude quantization error (AQE). Four essential conditions for the quantization process are presented. The paper also analyzes how the quantization error inherently varies with the phase angle. Simulation and experimental results are provided to validate the theoretical conclusions. The results show that the quantization errors exhibit a periodic distribution, with the error period being 1 / N of the signal cycle, where N denotes the number of samples per signal cycle. Within each error period, the quantization errors are symmetrically distributed. Moreover, a series of zero-points of the phase angle quantization error is derived, which are independent of both the conversion resolution and the signal amplitude. By adjusting N to link these zero-points with the desired phase angle, new application opportunities arise, which is expected to contribute to the advancement of phase angle standards and impedance bridge technology, and promote the use of high-speed, low-power, and cost-effective digital-to-analog converters.
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CHENG Qian, HAO Can, LI Yang, GAO Chao, LIU Tong, DONG Dengfeng
2025,45(5):10-18 ,DOI: 10.11823/j.issn.1674-5795.2025.05.02
Abstract:
The diversity of materials and complex geometric shapes of the intelligent manufactured components lead to sparse 3D point clouds at edge regions, resulting in non-uniform density distribution across complex mechanical parts. This study proposes a hybrid filtering method integrating density-adaptive SOR and ROR to remove multiple noise types of complex component point clouds. The method firstly merges voxels of the segmented point clouds based on density similarity, then establishes minimum neighborhood points for ROR using merged voxel size exponents, afterward determines search radius through neighborhood average distances, and calculates SOR standard deviations using scaling coefficients. The proposed method was tested using classical 3D point cloud models. Experiment results demonstrates that the edge retention of post-processed point clouds significantly exceed those achieved by fixed-parameter filtering methods, while effectively preserving detail information in sparse regions, and the noise removal rate is also improved. Robustness tests conducted under varying noise levels confirm the consistent performance across different noise intensities. This method establishes a technical foundation for online inspection in intelligent manufacturing systems requiring high-fidelity geometric reconstruction.
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HUANG Zhengwei, SU Piqiang, GUO Jie, SU Xizhi, DONG Jing
2025,45(5):19-29 ,DOI: 10.11823/j.issn.1674-5795.2025.05.03
Abstract:
To meet the requirements of multi-point and multi-parameter signal transmission in the limited installation space of the rotating parts test equipment for aeroengines, a six-module antenna based on a wireless telemetry system was developed. The design of the transmitting and receiving modules was made based on microstrip antenna technique to achieve the miniaturization of the device. The antenna model after packaging was established in the simulation software, and the influences of the thickness of the packaging glue, the dielectric constant of the material, and the tangent of the loss angle on the reflection coefficient (S11) and transmission coefficient (S21) of the antenna feeding port were analyzed. According to the simulation results, the design parameters were optimized, and the six-module antenna was developed and its performance was tested. The results show that the working frequency range of the antenna is 1.3 ~ 1.7 GHz, and the working bandwidth is not less than 40 MHz, which meets the signal transmission design requirements. Low-speed rotation tests were conducted under the conditions that the installation distances between the rotor and stator antennas were 8 mm and 10 mm, respectively, and high-speed rotation tests were conducted under the conditions of a rotational speed of 20 000 r / min and an ambient temperature of 80 ℃. The data packet loss rate of the system was less than 1% in both cases. The developed six-module antenna can reliably and efficiently transmit data from 60 measurement points and multiple types of data, providing strong support for the performance testing of rotating components such as compressors and turbines in aeroengines.
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SHI Jinlong, FENG Lingling, ZHANG Lei, CHEN Yinsheng
2025,45(5):30-39 ,DOI: 10.11823/j.issn.1674-5795.2025.05.04
Abstract:
Aiming at the problem that the research on the reliability assignment method of the shore-landing unloading system is not perfect and the reliability assignment results need to be optimized, a reliability assignment method based on the improved whale optimization algorithm (IWOA) was proposed. According to the parallel and series logical relationships existing among various tasks of the shoreline unloading system, a reliability assignment model of the unloading system was constructed, and reliability allocation method based on the IWOA was designed to complete the relia-bility allocation of tasks. The simulation method was used to evaluate the assignment results of the proposed method, and the reliability assignment method for shore unloading operation was verified. The simulation results show that the optimal reliability of the system is 0.975, which can enhance the task reliability allocation capability of the shore unloading operation system.
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LI Fuqiang, CHEN Peng, XIE Jiqing, CHEN Yongdang, CHANG Zhiyong
2025,45(5):40-47 ,DOI: 10.11823/j.issn.1674-5795.2025.05.05
Abstract:
Aiming at the problem that the efficiency and accuracy of existing measurement methods for geometric features of large-radius short arcs are difficult to meet the inspection requirements of mass-produced parts, a new measurement method is proposed. Firstly, a coordinate measuring machine is used to measure the two straight edges connected to the arc, and the intersection coordinates and included angle of the two straight lines are calculated. Then, the direction vector of the angle bisector is solved. The coordinate measuring machine is used to approach the workpiece along the direction vector from the intersection of the two straight lines, and the contact point between the coordinate measuring machine probe and the arc is recorded. The distance between the contact point and the intersection of the two straight lines is calculated, and finally the arc radius is obtained based on this distance. Experiments were conducted to verify the application effect of the proposed method, and the results show that compared with traditional measurement methods, this method has higher measurement accuracy and shorter time consumption. The research results are of great significance for promoting technological progress in the field of high-end manufacturing.
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LIU Yuxuan, GUO Caiguohui, YU Chong, LI Chengcheng, Wang Luowen
2025,45(5):48-67 ,DOI: 10.11823/j.issn.1674-5795.2025.05.06
Abstract:
With the rapid development of industry and manufacturing in China, the traditional maintenance methods of mechanical equipment gradually can't meet the requirements of high-efficiency production, and the demand for real-time monitoring of mechanical equipment operation status is constantly rising. In recent years, the development and application of digital twin technology provide a new idea for the monitoring of mechanical equipment operation status. This paper describes the importance of mechanical equipment operation status monitoring and the basic concept of digital twins, focuses on the analysis of the relevant theory of information fusion in the field of digital twins, combs the multi-information fusion status monitoring technology, summarizes the advantages and disadvantages of each theory, and makes a comparative analysis. Finally, according to the research status of information fusion theory, the prospect is made from the application goal-oriented construction of digital twin model, the exploration of intelligent model real-time update technology, and the construction of sensor digital twin model, which provides a reference for the research and development of digital twin driven mechanical equipment operation status monitoring technology in the future.
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ZHANG Weiwei, CHEN Zuowei, ZHAO Wei, YANG Beiya, JIA Hengyue, PAN Wei, SHI Haobin
2025,45(5):68-78 ,DOI: 10.11823/j.issn.1674-5795.2025.05.07
Abstract:
To explore the application of quantum walks in metrology, generalized Grover quantum walks and stepwise Grover quantum walks with arbitrary control parameters are proposed. The correlation between the corresponding clustering phenomena and the model's adjustable parameters were studied. The role of control parameters in the evolution of quantum walks was analyzed, revealing a clustering phenomenon based on control parameters: the evolution speed of the walker shows consistency with the entanglement between its coin space and position space. Further investigation into the probability distribution of the walker in different clusters shows that the probability distributions in each cluster exhibit different characteristics. In some clusters, the distribution tends to be concentrated, while in others, it is more dispersed. The experimental implementation of Grover quantum walks is discussed, and the applications of Grover quantum walks in metrology are addressed, highlighting their significance in achieving high-precision sensing, topological order measurement, and enhanced state tomography efficiency. The research findings provide strong support for the development of quantum walk-based information processing technologies.
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LUO Guoxi, ZHANG Yuzhuo, JIA Zeng, LI Wenyan, ZHAO Libo
2025,45(5):79-89 ,DOI: 10.11823/j.issn.1674-5795.2025.05.08
Abstract:
Traditional strain gauges face challenges such as significant strain transfer errors and slow response during monitoring, severely limiting the engineering effectiveness. To addresses the monitoring requirements for strain, vibration, and clamp looseness in aviation hydraulic pipelines, this paper proposed a design and manufacturing method for in-situ preparation of thin-film strain sensors on hydraulic pipelines. A finite element analysis model for strain transfer errors was established, and the structural parameters of the resistive strain grating were optimized. Multi-layer hetero-thin films, including the Ni80Cr20 strain-sensitive layer, were prepared using magnetron sputtering technology. Through a five-axis laser etching process, the laser incidence angle and focal position were adjusted in real-time, achieving a high-precision control over the etching depth. Testing revealed that the prepared thin-film strain sensor exhibited a drift rate (DR) of 8.4 × 10-5 h-1, a temperature coefficient of resistance (TCR) of 1.3 × 10-4 ℃-1 in the range of -40 ~ 100 ℃, a gauge factor (GF) of 2.03 in the strain range of 0 ~ 500 με, and a response time of just 15 ns. Force hammer experiments confirmed the sensor's ability to detect and identify key information such as strain, vibration, and clamp tightness. This integrated manufacturing sensor holds promising applications in the field of aviation hydraulic pipeline condition monitoring.
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SUN Xiaoqiang, FU Dongbo, ZHOU Xuanyu, HAO Wenhui, CHEN Longquan, ZHANG Dayuan
2025,45(5):90-96 ,DOI: 10.11823/j.issn.1674-5795.2025.05.09
Abstract:
A Brillouin frequency shift parameter calibration method based on optical carrier suppression modulation technology is proposed to meet the metrological calibration requirements for frequency shift of Brillouin optical time domain reflectometer (BOTDR) in distributed fiber sensors. Fiber Brillouin scattering signals were simulated using the frequency doubling signal generated by optical carrier suppression modulation technology, and a mathematical model and value traceability diagram between the Brillouin frequency shift reference value and the output signal frequency of the signal generator were provided, to achieve the value traceability of Brillouin frequency shift to the atomic time standard reference device. By adjusting the frequency of the output signal of the signal generator, the Brillouin frequency shift indication error at different frequency points within the frequency shift range can be obtained. Experiments were conducted to obtain calibration results for different frequency shift points within the range of 10.6 to 11.8 GHz, and an uncertainty analysis was performed. When the measured Brillouin frequency shift value is 10 998.38 MHz, the expanded uncertainty is 0.07 MHz (k = 2). This calibration method can meet the metrological traceability requirements for BOTDR frequency shift in the field of fiber optic sensing applications, providing strong support for promoting the performance improvement and widespread application of BOTDR.
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ZHANG Chenyang, LIU Guangshun, MA Pengfei, CHEN Yinsheng
2025,45(5):97-107 ,DOI: 10.11823/j.issn.1674-5795.2025.05.10
Abstract:
To address the need for multi-component gas detection in complex environments, this paper presents the design and implementation of a portable multi-channel gas detection system based on metal-oxide semiconductor (MOS) sensors. The system integrates an eight-channel sensor array, a high-precision signal-acquisition circuit, and a low-power hardware. A multi-branch convolutional neural network combined with a bidirectional long short-term memory network is employed to achieve automatic feature extraction and temporal modeling of multi-channel signals. Experiments using CO, C2H5OH, and their interfering gases and mixtures as the research subjects demonstrate that the system exhibits linear responses and high detection accuracy across different ranges of concentration. Comparative tests validate that the sensor-fusion strategy improves classification accuracy, enhances robustness, and increases adaptability to complex environments, with the classification accuracy for mixed gases reaching up to 100%. This study provides a reliable technical basis and practical reference for multi-component gas detection in environmental monitoring, industrial safety, and public health applications.
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ZHENG Dezhi, DONG Xiaoyuan, CHEN Aobei, SUN Ying, HU Chun, WANG Shuai
2025,45(5):108-117 ,DOI: 10.11823/j.issn.1674-5795.2025.05.11
Abstract:
To meet the stringent requirements for high accuracy, wide dynamic range, and rapid response of pressure sensors under the complex operating conditions of high-speed train traction and braking systems, this study presents the design, fabrication, and multiphysics optimization of a high-performance piezoresistive pressure sensor chip. By emplo-ying multiphysics coupling modeling theory in combination with a structural parameter optimization approach, this study systematically investigates the synergistic influence of diaphragm thickness, piezoresistor layout, and doping concentration on sensor performance, and proposes a parameterization-based stiffness-sensitivity co-optimization strategy for the diaphragm. Furthermore, by developing an eight-mask photolithography process and a composite wet etching technique based on KOH / IPA, a submicron-level control accuracy of diaphragm thickness was achieved. Finite element simulation results demonstrate a sensitivity of 56.987 mV / kPa, a nonlinearity of 0.048% FS, and structural stability under 300% overpressure. This work addresses a key technological bottleneck in high-accuracy pressure sensor fabrication and lays the foundation for fully localized production of safety-critical sensing components in next-generation traction systems for high-speed train.
Volume 45,2025 Issue 5
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Online Measurement and Compensation of Six-Degree-of-Freedom Errors for Z-Axis of micro-nano CMMs
Abstract:
As a key component in micro/nano machining and measurement equipment, the Z-axis is subject to manufacturing and assembly errors, which introduce six-degree-of-freedom (6-DOF) geometric errors that directly degrade metrology and machining precision. A measurement method is proposed for the Z-axis linear and angular errors based on laser interferometry and autocollimation. An error compensation model is established by analyzing the spatial position errors of functional points on the CMM, founded on Abbe and Bryan principles. The proposed method was implemented on a micro/nano-CMM, where an online 6-DOF error measurement system were developed. Measurements were performed along the Z-axis on a grade 0 gauge block with a thickness of 8 mm using the CMM. The results show that the measurement standard deviation and indication error were reduced by 54.6% and 54.3%, respectively, after compensation. This method and system provide a reliable solution for improving the measurement and machining accuracy of CMMs and other precision equipment.
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Research on Phase Noise Analysis and Suppression Methods in White Light Interference Signals
MA Long, LI Ying, HAO Jingtang, LIANG Kun, YIN Xutao, PEI Xin
Abstract:
White light interferometry, owing to its non-contact feature, high precision, and high adaptability, has been widely applied in micro-nano manufacturing and advanced equipment inspection. However, in practical measurement, interferograms are often affected by multiple factors such as light source instability, scanner nonlinearity, and environmental disturbances, leading to increased phase noise and reduced measurement accuracy and robustness. This work summarizes our research group""s studies on phase noise analysis and suppression in white light interferometry, where several comprehensive multi-source phase noise models have been established to address random fluctuations, dispersion errors, and vibration effects. Corresponding noise suppression strategies are proposed, significantly enhancing measurement stability and resolution. Experimental validations on standard samples, semiconductor devices, and metal structures demonstrate the proposed methods"" effectiveness in phase noise reduction and accuracy improvement, indicating strong potential for applications in advanced manufacturing.
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FMCW Laser Ranging Method Based on Electro-Optic Double-Sideband Modulation
CUI Hang, ZHANG Hengkang, WANG Shuzhen, SUN Haifeng, MENG Xiawei, ZHANG Shuwei, LI Xiaoping
Abstract:
Frequency modulated continuous wave (FMCW) laser ranging offers high accuracy and stability, making it valuable for aerospace measurement and related fields. Conventional FMCW systems typically rely on tunable lasers or dual-source architectures, which increases system complexity and engineering difficulty, and they suffer from error amplification in dynamic scenarios. To address these issues, we propose an FMCW laser ranging method based on electro-optic double sideband modulation. A single-frequency laser combined with an electro-optic modulator generates two oppositely chirped signals, reducing the system footprint and canceling motion-induced dynamic errors. In addition, an all-phase fast Fourier transform algorithm is designed to deliver stable and reliable phase estimation under high-dynamics and high-noise conditions. A Kalman filter is further introduced to optimize dynamic state estimation and ?improve ranging stability. Experimental results show that, under long-range conditions with 20 m of inserted optical fiber, the absolute distance measurement error does not exceed ±20 μm; for sinusoidal vibration targets with amplitude ≤500 nm and frequency ≤200 Hz, the measurement error does not exceed ±30 nm, which verifies the high reliability of the proposed system in both absolute distance and relative displacement measurements.
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Laser Ranging Based on Optical Frequency Combs: Status and Perspectives (Invited)
Abstract:
Laser ranging systems are advanced ranging systems that integrate laser and optoelectronic detection technologies. With advantages such as high resolution, strong anti-interference capability and compact size, they have attracted extensive attention in recent years. At present, laser ranging has been widely applied in fields including autonomous driving, artificial intelligence and military defense. Driven by complex application demands, high detection resolution, fast update rate and long detection range have become the core goals for the continuous iteration and upgrading of laser ranging technology. Optical frequency comb, whose spectrum consists of a series of evenly spaced discrete frequency components with stable phase relationships and which simultaneously provides time-domain pulses with stable spacing, serves as a natural “time–frequency” reference and “photon–radio-frequency” bridge. It has been widely used in precision metrology, high-speed communications, microwave generation and fiber-optic sensing. In recent years, the rapid development of optical frequency comb technology has significantly improved the performance of laser ranging systems, creating new advantages in terms of measurement accuracy, speed and range, and becoming an important breakthrough for extending the functionality and enhancing the performance of next-generation laser ranging systems. This review focuses on laser ranging technologies based on optical frequency combs, provides an overview of the principles, characteristics and development status of optical frequency combs, summarizes typical methods and recent research progress in comb-based ranging, and finally presents a summary and outlook on the current research status and future development of this field.
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Research Progress on Accurate 3D Shape Measurement of Complex Scenes Based on Structured Light Illumination
Qican Zhang, Zhoujie Wu, Yajun Wang, Yuankun Liu
Abstract:
Structured-light illumination three-dimensional (3D) measurement technology is characterized by non-contact operation, high precision and high flexibility. It accurately provides detailed information such as object contour dimensions, surface shape, and even deformation data, making it the most widely adopted method for 3D information digitization. This technique has found significant applications across multiple fields, offering robust support for solving practical problems and advancing scientific research. This paper outlines the technical principles of commonly used methods in this domain and presents case studies conducted by the research team, including high-precision 3D shape measurements of large-scale fossil fault planes, high-dynamic-range workpieces, rapidly evolving dynamic processes, and large-aperture smooth optical components. Furthermore, it summarizes existing challenges and future trends in structured illumination-based 3D shape measurement, providing valuable references for 3D shape measurement in complex scenarios.
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Optimization Algorithm for the Deployment of Heterogeneous Nodes in Energy-Isoform Sensor Networks
Abstract:
The wireless sensor network is a crucial component of the Internet of Things (IoT), and ensuring its efficient operation has become one of the prominent research challenges today. By incorporating energy-replenishable heterogeneous nodes into the network, it is possible to effectively extend the network's lifespan. This paper establishes criteria for selecting the locations of heterogeneous nodes based on characteristics such as network coverage and data transmission distance. We propose an optimization deployment algorithm specifically designed for positioning heterogeneous nodes within heterogeneous wireless sensor networks, and we conduct a simulation analysis comparing our proposed algorithm with existing methods. The results indicate that our proposed algorithm demonstrates superior performance in terms of data transmission volume and energy consumption.
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Measurement of microwave using Rydberg atomic superheterodyne
Abstract:
Microwave measurement technology is widely used in data communication, radar detection, satellite positioning and navigation, meteorology, and other fields, and has become a key strategic need in aviation worldwide. Compared to traditional microwave measurement methods, microwave precision measurement technology based on Rydberg atoms, due to their large electric dipole moment, high polarization rate, and sensitivity to external electromagnetic fields, not only offers superior resolution and sensitivity, but also provides non-destructive measurement and a wide frequency response from electrostatic fields to terahertz. This article introduces the physical principles and measurement methods of microwave measurement using Rydberg atoms, focusing on the research progress in improving measurement sensitivity, phase measurement, and dynamic range using superheterodyne microwave technology for Rydberg atoms, and analyzes its future application directions in the aviation field.
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Research progress on applications of scanning tunneling microscopy in atomic-scale measurement, characterization, and manufacturing
CHAI Yu, CHEN Dezhang, LI Dezhi, LYU Kaihang, LI Haopeng, DANG Chaoqun, JU Bingfeng
Abstract:
The scanning tunneling microscope (STM) is a pivotal instrument that integrates the capabilities of atomic-scale measurement, characterization, and fabrication. It simultaneously fulfills the three core requirements of atomic-scale manufacturing: "visualization," "precision measurement," and "fabrication feasibility." Atomic-scale manufacturing aims for precise manipulation at the spatial scale of meters, with associated electronic dynamics occurring on ultrafast timescales ranging from femtoseconds to attoseconds. With its high spatiotemporal resolution, STM serves as a key experimental technique for revealing physical mechanisms and quantum effects at the atomic scale, significantly advancing the field from fundamental exploration to practical application. Based on the unique quantum tunneling effect, STM performs precise measurements of physical properties (e.g., electronic and magnetic) in fabricated structures. This establishes quantitative structure-property relationships between fabrication parameters and device performance,thereby providing a critical basis for process optimization and quality assessment. Furthermore, STM possesses the inherent ability for precise atomic-scale manipulation. The deep integration of STM with high-throughput and automation technologies is emerging as a core pathway to transition STM-based atomic-scale manufacturing from laboratory proof-of-concept to industrial application. This review summarizes the current research progress in the application of STM for atomic-scale measurement, characterization, and manufacturing, outlines existing challenges, and provides perspectives on future development trends.
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Calibration of Convective Heat Flux Using a Dual-Plate Transient Method
ZHENG Jianhua, WANG Xiaolu, HU Lintao, KONG Xiangxue, ZHAO Yijun
Abstract:
Accurate heat flux measurement is essential for developing hypersonic vehicles and their thermal protection systems. To address the lack of reliable calibration methods for heat flux sensors under high-temperature, high-speed conditions, this study introduces a dual-plate transient calibration technique. A highly accurate thin-film platinum resistance sensor is used as a reference, installed alongside a Gardon gauge on a rapid-insertion mechanism within a wind tunnel. Calibration experiments conducted at 0.3 Ma and temperatures from 100 to 300 °C successfully determined the convective heat flux sensitivity coefficient of the Gardon gauge. This method provides a novel and effective approach for sensor calibration under extreme conditions, significantly improving measurement reliability and offering robust technical support for hypersonic vehicle development.
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Research on the Influence of Ni Content and Film Thickness on the Environmental Stability of PdNi Hydrogen Sensors
Abstract:
Oxygen and water vapor significantly affect the hydrogen sensitivity of PdNi thin films. To achieve hydrogen concentration monitoring in environments containing oxygen and high humidity—such as electrolytic water hydrogen production stations, nuclear power plant storage, and deep-sea energy exploration—PdNi thin film hydrogen sensors were fabricated using magnetron sputtering, photolithography, and plasma etching. By controlling the Ni content and thickness of the PdNi films, this study investigated their influence on sensor stability under oxygen and humid conditions. Characterization techniques including XRD (X-ray Diffraction), SEM (Scanning Electron Microscope), and XPS (X-ray Photoelectron Spectroscopy) were employed to analyze the crystallinity, elemental composition, and valence states of the films. Experimental results indicate that higher Ni content leads to greater susceptibility of the PdNi film's hydrogen response to interference from water vapor and oxygen. Conversely, increased film thickness mitigates this interference effect, albeit at the cost of reduced intrinsic response sensitivity. Notably, a PdNi film sensor with a thickness of 24 nm and Ni content of 8.02% demonstrated the ability for its response curve to recover to its pre-exposure state after experiencing water vapor, despite being affected by both water vapor and oxygen.
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Full-field spectral-domain interferometry and its application based on digital micromirror device
Abstract:
Spectral-domain interferometry has been widely applied in base station degree-of-freedom measurement, probe-type fiber optic sensing, and biological tissue imaging. To decouple target parameters, it is typically necessary to acquire magnitude responses across the spectrum. By detecting periodic spectral fringe frequencies and combining phase information at each optical frequency, followed by algorithmic iteration, micro/nano-scale measurements can be achieved. However, current full-field spectral-domain interferometry relies on wavelength or galvanometer scanning, which limits its ability to capture full-field information in a single acquisition. Digital micromirror devices (DMDs) feature high resolution, fast measurement speed, and flexible programmability. To address this challenge, this paper proposes a full-field spectral-domain interferometry technique based on a digital micromirror device. By leveraging spatial light field encoding and decoding, the system enables full-field spectral detection, with applications in both spectral interferometric distance measurement and spectroscopic ellipsometry for thin-film thickness measurement, demonstrating its potential in micro/nano topography characterization. The proposed method is particularly suitable for rapid 3D structure recovery and reconstruction of sparse surfaces, eliminating the need for wavelength or galvanometer scanning and significantly improving full-field measurement efficiency. Potential applications include thickness and morphology characterization of polished wafers, silicon-on-insulator (SOI) substrates, and bonded interfaces.
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Design and Verification of Small-scale Space Optical Payloads for Batch Production
Cheng Xin, Xue Zhipeng, Liu Jinquan, Miao Zijian, Wang Sheng
Abstract:
Massive satellite constellations are rapidly developing. Space optical payloads now require batch manufacturing. This research aims to break traditional bottlenecks of high costs and long cycles. It focuses on modular design, process optimization, and automated testing for micro-sized space optical payloads. A Maksutov-Cassegrain optical system is developed. It combines a small F-number with tiny pixels. At 500 km orbital height, it achieves 4.5 m ground sample resolution. Its imaging swath is 13.5 km × 13.5 km. The total weight is only 1.1 kg. Modular design allows interchangeability between lenses and focal plane components. Centering assembly technology significantly improves alignment efficiency. Automated assembly and calibration lines complete system integration and focal plane calibration. Overall development efficiency increases by 50%. These results provide key technical support. They help further reduce development time and cost for micro-sized space optical payloads.
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Research on Hybrid GR&R Method of Hardness Automatic Testing System Based on Process Decoupling
Abstract:
In view of the dual characteristics of "automation" and "destructiveness" of the automatic hardness testing system, this paper systematically expounds the particularity of its measurement system analysis (MSA), and points out the limitations of the traditional Gauge Repeatability and reproducibility (GR&R) method in the identification of variation sources and experimental design. On this basis, a "process decoupling hybrid GR&R" experimental strategy is proposed, which decouples the hardness testing process into two sub processes: indentation generation (destructive) and indentation measurement (non-destructive). Nested design and cross design are used to separate and quantify the variation sources, respectively. Through the construction of double detection unit automation platform, the systematic MSA experiment was carried out, and the analysis of variance was used to evaluate the influence of equipment repeatability, reproducibility and interaction. The results show that the proposed method can effectively identify the dominant variation sources, and provide a feasible analysis framework for the performance evaluation and optimization of the hardness automatic testing system, which has strong engineering applicability and popularization value.
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Research on the Localization Accuracy of Spot for Four-Quadrant SNSPDs
Abstract:
The Four-Quadrant Superconducting Nanowire Single-Photon Detector (QD-SNSPD) enables high-precision and rapid spot localization by measuring photon count differences across its four quadrants, showing great potential in deep-space laser communication and weak target detection. However, the recovery time effect of SNSPD introduces errors under high count rates, and spot localization under low signal-to-noise ratio (SNR) remains challenging. This study introduces a nonlinear count correction mechanism based on SNSPD recovery characteristics and derives a corrected Gaussian model for spot localization. To mitigate signal reduction on positive and negative half-axes in low-SNR environments, a non-integer power operation method is proposed. Simulations and experiments demonstrate improved accuracy with count correction at high count rates and reduced localization errors using the power operation under low SNR. Compared to classical half-axis differential localization, the 1.4-power operation reduces error by 27% at SNR < 10, while the corrected Gaussian model achieves a 70% error reduction at SNR > 50. Positioning standard deviation <0.01 spot radius can be achieved when photon counts exceed 10?.These findings provide valuable insights into high-precision spot localization and method selection for QD-SNSPD.
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Influence Mechanism of Beam Incident Angle on Angular Measurement Accuracy and Compensation in Rotational Scanning Systems
Abstract:
Rotational laser scanning angular measurement systems have been widely applied in large-scale structural assembly and spatial pose monitoring due to their distributed architecture, high accuracy, and efficiency. However, variations in receiver orientation lead to changes in the beam incidence angle, introducing systematic angular measurement errors that affect the system’s precision and robustness. To address this issue, a local projection model and a Gaussian light-strip distribution model were established based on beam propagation geometry and receiver structural characteristics, and differences in photoelectric response under different incidence conditions were analyzed. Furthermore, by incorporating attitude information provided by an inertial measurement unit (IMU), an effective receiving surface model was constructed in the receiver coordinate system, and an error compensation method considering receiver structural features was proposed. Simulation results show that as the incidence angle increases, the photoelectric response waveform of the receiver becomes significantly asymmetric, with angular measurement errors reaching several tens of arcseconds. The proposed compensation method effectively corrected these errors, reducing the root-mean-square (RMS) error by approximately 90%. In precision turntable experiments, the roundness error of the receiver trajectory decreased from 0.81 mm before compensation to 0.17 mm after compensation, confirming the effectiveness of the compensation model. The study enriches the error modeling framework of rotational laser scanning systems and provides an effective approach to enhance measurement accuracy and robustness under varying receiver attitudes.
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A Study on the Natural Environmental Test Methods for the Metrological Performance of Airborne Sensors
SHI Chunying, ZHANG Yixiang, HU Wanxin, XING Runjia
Abstract:
Airborne sensors must endure the long-term effects of the natural environment at airports. To accurately evaluate their metrological performance under the prolonged, gradual, and cumulative influence of the natural environment, this study examines key technical aspects of the testing process—including preliminary preparations, test design, execution, result analysis, and reporting—based on the characteristics of both airborne sensors and natural environments. This exploration has resulted in the development of a relatively universal methodology for conducting natural environmental tests. These tests generate fundamental data on changes in sensor metrological indicators, providing essential support for subsequent research on performance degradation and calibration cycle of airborne sensors.
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Research on multi-source DEM generation and fusion method based on unmanned aerial vehicle and satellite remote sensing
WANG Siyu, CUI Yuguo, CHEN Jichi
Abstract:
To improve the quality and efficiency of digital elevation model (DEM) construction in complex terrain, this study proposes a multi-source DEM acquisition and fusion method that integrates high-resolution optical imagery and interferometric synthetic aperture radar (SAR) imagery. Using an unmanned aerial vehicle and satellite remote sensing system as a platform, this method constructs a multi-view data acquisition chain to generate optical imagery DEM and interferometric SAR-DEM, respectively. By introducing a point cloud classification algorithm based on texture and structural features and a regional adaptive weight estimation model, achieving weighted fusion of multi-source elevation data. The fusion process employs error constraints and edge control strategies to address typical challenges such as terrain occlusion, data holes, and elevation jumps. Experimental validation in representative landforms, including forests, glaciers, deserts, cities, and water bodies, demonstrates that this method achieves excellent elevation recovery accuracy and boundary continuity, adapting to the three dimensions modeling needs of various landform types. This research provides stable and reliable technical support for applications such as high-resolution terrain mapping, landform evolution monitoring, and disaster early warning, and is of great significance for advancing the automation and intelligence of remote sensing mapping.
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Porous parameter inversion based on irregular sound incidence
Abstract:
Parameter inversion is an important means to obtain the material porous parameters, and the related principles and methods have been extensively investigated in recent years. The existing inversion researches are mainly based on the normal incidence acoustic model, while there is almost no investigation using irregular incidence sound model to invert porous parameters. This article studies the inversion method of porous materials under irregular sound incidence case. Here, the theoretical relationship was established between the porous parameter and irregular incidence absorption coefficient. The inversion study was conducted by using the established theoretical model, porous acoustic model and genetic algorithm, and the accuracy and astringency of inversed parameters was further analyzed. It's theoretically and numerically demonstrated that, the prediction and simulation results are in good agreement, and the inverted porous parameters by using irregular sound incidence model present high accuracy and astringency, which is expected to provide theoretical reference for porous parameter inversion analysis.
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