Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2024-05-06
Abstract: In this work, a design of transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA with the tip-sample component in CryoSTM is called as CryoSTM-TIA. With transimpedance gain of 1 Gohm, the bandwidth of the CryoSTM-TIA is larger than 200 kHz. The distinctive feature of the proposed CryoSTM-TIA is that its pre-amplifier is made of a single cryogenic high electron mobility transistor (HEMT), so the apparatus equivalent input noise current power spectral density at 100 kHz is lower than 6 (fA)2/Hz. In addition, bias-cooling method can be used to in-situ control the density of the frozen DX- centers in the HEMT doping area, changing its structure to reduce the device noises. With this apparatus, fast scanning tunneling spectra measurements with high-energy-resolution are capable to be performed. And, it is capable to measure scanning tunneling shot noise spectra (STSNS) at the atomic scale for various quantum systems, even if the shot noise is very low. It provides a powerful tool to investigate novel quantum states by measuring STSNS, such as detecting the existence of Majorana bound states in the topological quantum systems.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties submitted time 2024-05-06
Abstract: In this work, we design and fabricate the transimpedance Amplifier (TIA) following the design mentioned in Ref. 1 . In the TIA, the preamplifier (Pre-Amp) is made of a junction field effect transistor (JFET) that can work at 77 K. The post-amplifier (Post-Amp) is made of an operational amplifier. Cascade Pre-Amp and Post-Amp to form the inverting-amplifier. With a 1.13 Gohm feedback network, the gain of TIA is 1.13 Gohm and its bandwidth is about 97 kHz. The equivalent input noise voltage power spectral density of TIA is not more than 9 (nV)2/Hz at 10 kHz and 4 (nV)2/Hz at 50kHz, and its equivalent input noise current power spectral density is about 26 (fA)2/Hz at 10 kHz and 240 (fA)2/Hz at 50 kHz. The measured transport performances and noise performances of TIA are consistent with the simulations and calculations. As an example, the realization of TIA in this work verifies the design method and analytical calculations for the low-noise large-bandwidth high-gain TIA proposed in Ref. 1,2 . And, the TIA in this work is perfect for the cryogenic STM working at liquid nitrogen temperature.
Peer Review Status:Awaiting Review
Subjects: Information Science and Systems Science >> Basic Disciplines of Information Science and Systems Science Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics Subjects: Electronics and Communication Technology >> Optoelectronics and Laser Subjects: Physics >> Geophysics, Astronomy, and Astrophysics Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2024-04-08
Abstract: The Einstein’s theory of special relativity is based on his two postulates. The first is that the laws of physics are the same in all inertial reference frames. The second is that the velocity of light in the vacuum is the same in all inertial frames. The theory of special relativity is considered to be supported by a large number of experiments. This paper revisits the two postulates according to the new interpretations to the exact solutions of moving sources in the laboratory frame. The exact solutions are obtained using the classic Maxwell’s theory, which clearly show that the propagation velocity of the electromagnetic waves of moving sources in the vacuum is not isotropic; the propagation velocity of the electromagnetic waves and the moving velocity of the sources cannot be added like vectors; the transverse Doppler effect is intrinsically included in the fields of the moving sources. The electromagnetic sources are subject to the Newtonian mechanics, while the electromagnetic fields are subject to the Maxwell’s theory. We argue that since their behaviors are quite different, it is not a best choice to try to bind them together and force them to undergo the same coordinate transformations as a whole, like that in the Lorentz transformations. Furthermore, the Maxwell’s theory does not impose any limitations on the velocity of the electromagnetic waves. To assume that all objects cannot move faster than the light in the vacuum need more examinations. We have carefully checked the main experiment results that were considered as supporting the special relativity. Unfortunately, we found that the experimental results may have been misinterpreted. We here propose a Galilean-Newtonian-Maxwellian relativity, which can give the same or even better explanations to those experimental results.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Radar Engineering submitted time 2024-01-31
Abstract: Among various methods to detect the ship targets in Synthetic Aperture Radar(SAR) image, the Constant False Alarm Rate (CFAR) detection algorithm with an adaptive detection threshold is the most important and extensively used one. In order to improve the detection performance of the ships in SAR image, various statistical distributions are used, with an attempt to accurately model the SAR clutter backgrounds, such as Gamma, K, log-normal, G0, the alpha-stable distribution, etc. In modern radar systems, the use of the CFAR technique is necessary to keep the false alarms at a suitably low rate in an a priori unknown time varying and spatially nonhomogeneous backgrounds, and to improve the detection probability as much as possible. The clutter background in SAR images is complicated and variable, when the actual clutter background deviates from the assumed statistical distribution, the performance of the parametric CFAR detectors will deteriorate, whereas the nonparametric CFAR method will exhibit its advantage. In this work, the Wilcoxon nonparametric CFAR scheme for ship detection in SAR image is proposed and analyzed. By comparison with several typical parametric CFAR schemes on 3 real SAR images of Radarsat-2, ICEYE-X6 and Gaofen-3, the robustness of the Wilcoxon nonparametric detector to maintain a good false alarm performance in these different detection backgrounds is revealed, and its detection performance for the weak ship is improved evidently. Moreover, the detection speed of the Wilcoxon nonparametric detector is fast and it has the simplicity of hardware implementation.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2024-01-30
Abstract: In the scope of our investigation, we have solved the stability problem of the boost converter. Ouyang Changlian's doctoral dissertation made me realize the importance of duty cycle in control system.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Communication submitted time 2024-01-07
Abstract: Configuration verification of networks, especially virtual private networks, is a complex task that needs to be done before every update of a production environment so that network providers can ensure network availability for their customers. This paper discusses a graph-based neural network (GNN) approach for detecting and locating configuration errors in IP virtual private networks (VPNS). The study focuses on two GNN models, one that focuses on routing misconfigurations between customer and provider edge routers, and the other on VPN routing misconfigurations between different provider edge routers. The goal is to provide a tool that simplifies the process of verifying an end-to-end VPN configuration.
In the study, both models were trained using a balanced dataset containing examples of tag configurations extracted from an IMSNetwork-based VPN deployment. The results show that both models show high accuracy when dealing with VPNS of different sizes (from 3 to 40 sites) and two types of architectures (full mesh and hub radiant).
The advantage of this method is that the graph neural network can capture the complex relationship between network topology and configuration, so that configuration errors can be detected more effectively. By using this technology, network providers can validate network configurations before each update to ensure network availability for their customers.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Information Processing submitted time 2024-01-07
Abstract: In recent years, with the rapid development of deep learning technology, image recognition based on convolutional neural networks (CNN) has achieved remarkable achievements in various fields. In the field of botany, flower species identification is an important research direction and is of great significance in ecology, agriculture, and environmental monitoring. This research aims to explore and optimize the application of ResNet (deep residual network) in flower type recognition tasks. First, the article conducts an in-depth analysis of the structure of the ResNet network, understands its mechanism for introducing residual learning, and how to effectively deal with the vanishing and exploding gradient problems in deep network training. Through preliminary experiments on a large-scale flower image data set, the excellent performance of ResNet in handling complex multi-category flower image recognition tasks was verified. In the data preprocessing stage, the article uses data enhancement techniques, including cropping and flipping, to expand the training data set and improve the generalization ability of the model. At the same time, the flower images are standardized to adapt to the requirements of the ResNet network for input data. Experimental results show that compared with the traditional CNN model, the flower type recognition model using ResNet has significantly improved accuracy and convergence speed. In addition, through in-depth analysis of the model's performance on different flower categories, it was found that the ResNet network performed better when processing flower images with hierarchical structures and complex shapes. The model proposed in this article not only achieves excellent performance overall, but also has high accuracy in identifying specific flower categories. In further research, we consider further improving the generalization ability of the model through transfer learning, especially when facing small sample flower data sets. At the same time, the real-time performance of the model will be explored to adapt to the need for rapid and accurate identification of flower types in real scenes.
This study provides a useful reference and reference for the application of deep learning in the field of botany by conducting a comprehensive and in-depth analysis of the advantages and applications of ResNet network in flower species recognition tasks. The research results not only have certain theoretical value for the improvement of flower identification technology, but also have extensive potential for promotion in practical applications.
Peer Review Status:Awaiting Review
Subjects: Nuclear Science and Technology >> Particle Accelerator Subjects: Electronics and Communication Technology >> Electron Technology submitted time 2023-11-29
Abstract: In light of the current international energy scarcity, nuclear power has emerged as a crucial source of clean energy. Proton accelerators have therefore become a pivotal technology in nuclear waste management. During beamline orbit correction processes, precise calculations of beamline orbit parameters are required. Given the demonstrated effectiveness of neural networks in a wide variety of industry domains, they offer promising potential for high-accuracy data fitting and prediction. Hence, this study proposes a novel direct linear accelerator beamline orbit parameter prediction technique based on edge intelligence computing nodes. This technique leverages BPNN to learn from historical data and generate a powerful model that can be seamlessly deployed to edge computing nodes, thereby accelerating the prediction of BPM location parameters. Furthermore, the proposed approach may be complemented by an adaptive compensation system in the future, which, in combination with edge computing nodes, could enable automatic beamline position correction, thereby achieving beamline orbit correction. Our experimental results demonstrate that FPGA, as an edge acceleration node, can achieve an inference speed of 2.5us, which represents a remarkable performance enhancement of approximately 165.6 times compared to CPU and approximately 7.9 times compared to GPU. The predicted results exhibit an average error of only 0.5%, and they exhibit the desired latency and accuracy characteristics.
Subjects: Electronics and Communication Technology >> Information Processing submitted time 2023-11-07 Cooperative journals: 《文献与数据学报》
Abstract: [Purpose/significance]Data fusion is an important way to realize multi-source data value.Comprehensive analysis of the overall topics of global data fusion research has an important scientific and technological information value for the current data fusion research. [Method/process]The hot topics and research methods of 16053 literatures from Web of Science core collections were analyzed by word-frequency and co-word analysis. [Result/conclusion]The data fusion research has shown a significant growth trend, and after more than 30 years development, core research hotspots and methods of data fusion have been formed. In the research, the data fusion of sensors (including wireless sensors) is the core research direction in this field. Fault diagnosis, remote sensing, security and smart grid are the hotspots of the data fusion scenario. Kalman Filter, Neural Network, Dempster-Shafer Evidence Theory and Machine Learning(including Deep Learning, Support Vector Machine, etc.) are the main methods in data fusion, and the synergy network of methods have been formed in data fusion.
Subjects: Electronics and Communication Technology >> Electron Technology submitted time 2023-06-15
Abstract: Analog IC design faces a series of challenges. Druing design phase, the number of performance indicators that need to be met increases rapidly, along with more non-ideal factors that need to be balanced. It is difficult to effectively meet the needs of design exploration and simulation scheduling by using simulation-oriented models alone. System-level modeling is required to comprehensively address performance metrics and design constraints, and to adopt agile design methodologies to improve the efficiency of analog IC design efforts. Based on the framework of decoupling and separating circuit model and performance index calculation, this paper proposes a system-level modeling method for analog circuits that can handle complex constraints. This method gives a domain-specific language suitable for analog integrated circuit system-level modeling. The language contains the syntax elements and syntax protocols required for system-level modeling. According to the characteristics of analog integrated circuits, this method gives the semantic correspondence between the semantics of the modeling language elements and the circuit characteristics, and gives a modeling method that treats analog circuit components, topology and design constraints as components in the system to achieve decoupling. The model obtained by the above method uses graph as the basic data structure and supports graph calculation. this paper also presents system-level modeling tools including domain-specific language compilation, model storage, graph computing and other functions. Modeling cases are given to show the usability and applicability of the modeling method. This work shows that system-level modeling provides a feasible solution for solving the decoupling of complex constraints in analog integrated circuit design.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter submitted time 2023-05-01
Abstract: In this work, a design of large-bandwidth high-gain low-noise transimpedance amplifier (TIA) for scanning tunneling microscope (STM) is proposed. The simulations show that the proposed TIA has the bandwidth higher than 200 kHz, two orders of magnitude higher than those of conventional commercial TIAs for STM. At low frequencies, the noises of the proposed TIA are almost the same as the conventional commercial ones with the same transimpedance gain. At high frequencies, its calculated input equivalent noise voltage power spectral density (PSD) is 40 (nV)2/Hz and its input equivalent noise current PSD is 3.2 (fA)2/Hz at 10 kHz. The corresponding values are 23 (nV)2/Hz and 88 (fA)2/Hz at 100 kHz. The STM with the proposed TIA can meet the needs of fast high-quality STM imaging measurements and fast high-energy-resolution scanning tunneling spectra measurements for the low-conducting materials, such as complex organic systems and wide bandgap semiconductors.
Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-05-01
Abstract: An ultra-low-noise large-bandwidth transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA connected with the tip-sample component in CryoSTM is called as CryoSTM-TIA. Its transimpedance gain is as high as 1 GΩ, and its bandwidth is over 300 kHz, but its equivalent input noise current power spectral density is less than 4 (fA)2/Hz at 100 kHz. The low inherent noise for the CryoSTM-TIA is due to its special design: (1) its pre-amplifier is made of a pair of low-noise cryogenic high electron mobility transistors (HEMTs); (2) the noise generated by one HEMT is eliminated by a large capacitor; (3) the capacitance of the cable connected the gate of the other HEMT to the tip is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. The dc output voltage drift of the CryoSTM-TIA is very low, as 5 μV/°C. The apparatus can be used for measuring the scanning tunneling differential conductance spectra, especially the scanning tunneling shot noise spectra (STSNS) of quantum systems, even if the shot noise is very low. It provides a universal tool to study various novel quantum states by measuring STSNS, such as detecting the Majorana bound states.
Subjects: Electronics and Communication Technology >> Electron Technology submitted time 2023-02-24
Abstract: Thyristor, RC damping circuit and valve arrester are the main part of primary loop of UHVDC valve, determining the cooperation the parameters of the three types of devices is the chief work in the electrical design of UHVDC valve, in this paper, the mechanism of the commutation overshoot was revealed, the interaction effect of the three types of devices was also confirmed, then the circuit differential equation was established , and the equation was solved by Piecewise fitting the reverse recovery current of thyritor, the precision of the calculation method that was put forward in the paper was proved by comparing the calculation results with the test results
Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2022-12-29
Abstract:
A low-noise high-gain large-bandwidth transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA connected with the tip-sample component in CryoSTM is called as CryoSTM-TIA. The CryoSTM-TIA has a transimpedance gain of 10 Gohm, a bandwidth of over 100 kHz, and an equivalent input noise current power spectral density less than 4 (fA)2/Hz at 100 kHz. The low inherent noise of the CryoSTM-TIA is due to its special design: (1) its pre-amplifier (Pre-Amp) is made of the low-noise cryogenic high electron mobility transistors; (2) the cascode-type configuration for the Pre-Amp is used to avoid Miller effect to reduce its input capacitance CA; (3) the capacitance of the cable connected the Pre-Amp input to the tip, i.e. CI, is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. Its high gain and large-bandwidth are realized together, due to the application of the frequency compensation in the feedback loop, the reduced CA, and the minimized CI. This apparatus can be used for fast high-energy-resolution measurements of scanning tunneling spectra for low conductivity materials, especially for measuring their scanning tunneling shot noise spectra.
Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2022-12-29
Abstract: Shot noise is a powerful tool to study quantum systems. In this work, a design of transimpedance amplifier (TIA) for a cryogenic scanning tunneling microscope (CryoSTM) is proposed to meet the requirements of the shot noise measurements for quantum systems. In the TIA, the preamplfier is made of the low-noise low-power cryogenic high electron mobility transistors. With the high transimpedance gain of 1 Gohm, the bandwidth of the proposed TIA is larger than 300 kHz. In the CryoSTM, the TIA with the tip-sample component is called as CryoSTM-TIA. The bandwidth of the proposed CryoSTM-TIA is still larger than 300 kHz. Its equivalent input noise current power spectral density is less than 30 (fA)2/Hz at 100 kHz. It is detailed, for quantum systems, by using the CryoSTM-TIA, how to measure scanning tunneling current spectra, scanning tunneling differential conductance spectra, and scanning tunneling noise current power spectra, in atomic scale, and then extract their scanning tunneling shot noise spectra. Thus, it is possible to study novel quantum phenomena in various quantum systems by measuring shot noise with the CryoSTM-TIA, such as the Andreev reflection in atomic scale, the Kondo effect in a single molecular magnet, and the existence of Majorana bound states, etc.
Subjects: Electronics and Communication Technology >> Other Disciplines of Electronics and Communication Technology submitted time 2022-10-21 Cooperative journals: 《桂林电子科技大学学报》
Abstract: To enhance the device-performance and long-term stability of printable mesoscopic perovskite solar cells (MPSCs),
an anion-cation synergistic strategy is proposed to introduce the ionic liquid additive 1-ethyl-3-methylimidazolium acetate
(EMIMAC) into the perovskite active layer and use it for the preparation of efficient and stable MPSCs. The experimental
results indicate that the imidazole (EMIM+ ) cation enables ionic defect passivation (e.g., Pb2+ and PbI3- ) through
the coordination effect, which is believed to be beneficial for perovskite crystallization. On the other hand, the acetate
(AC- ) anion tends to coordinate with TiO2 to passivate the oxygen vacancy defects on the TiO2 surface for improved interfacial
contact at the TiO2/perovskite interface. As a result, the synergistic effects of the EMIM+ cation and AC- anion in
the EMIMAC achieves better perovskite crystallinity, more efficient charge transport, and lower nonradiative recombination.
The power conversion efficiency (PCE) of the MPSCs increased from 13.83% to 15.48%, accompanied by a negligible
hysteresis. Furthermore, the unencapsulated MPSCs exhibited excellent long-term stability by maintaining 90% of the initial
PCE after exposure in air (RH=50±5%) for 60 days. The experimental results indicate that the ionic liquid additive
EMIMAC can effectively enhance the PCE and stability of the device, providing an effective strategy for further improving
the device-performance.
Subjects: Electronics and Communication Technology >> Information Processing submitted time 2022-06-07 Cooperative journals: 《桂林电子科技大学学报》
Abstract:在无线传感器网络(WSNs)中,数据分发是一种重要的传输方式,需要满足以下要求:可靠性,节能和可扩展性。然而,现有的研究工作很少关注数据分发中所存在的攻击,导致数据分发的可靠性大打折扣。为了检测出WSNs数据分发中的节点克隆攻击,保证数据分发的高可靠性,提出了基于单轮零知识证明的节点克隆攻击检测方案。本方案通过构建析取-叠加码生成专属于各个节点的数字指纹,在单轮零知识证明方案中对节点的数字指纹进行验证,可以检测出没有正确数字指纹的克隆节点。仿真表明使用提出的检测方案,可以保证WSNs在数据分发过程中的高可靠性. In wireless sensor networks (WSNs), data dissemination is an essential transmission mode, which needs to meet three requirements: reliability, energy saving and scalability. Existing research pays little attention to the attacks in data dissemination, resulting in a significant loss of the reliability of data dissemination. In order to detect node clone attacks in WSNs data dissemination and ensure high reliability of data dissemination, a node clone attack detection scheme based on single round zero knowledge proof is proposed. In this scheme, the digital fingerprint of each node is generated by constructing superimposed disjunct code, and the cloned node without correct digital fingerprint can be detected by verifying the digital fingerprint of the node in the single round zero-knowledge proof scheme. Simulation results show that the proposed scheme can ensure the high reliability of WSNs in the data dissemination process.
Subjects: Electronics and Communication Technology >> Information Processing Subjects: Engineering and technical science >> Engineering General Technology Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2022-02-08
Abstract:The spectral leakage (SL) from windowing and the picket fence effect (PEF) from discretization have been among the standard contents in textbooks for many decades. The SL and PEF would cause the distortions in amplitude, frequency, and phase of signals, which have always been of concern, and attempts have been made to solve them. This paper proposes two novel decomposition theorems that can totally eliminate the SL and PEF, they could broaden the knowledge of signal processing. First, two generalized eigenvalue equations are constructed for multifrequency discrete real signals and complex signals. The two decomposition theorems are then proved. On these bases, exact decomposition methods for real and complex signals are proposed. For a noise-free multifrequency real signal with m sinusoidal components, the frequency, amplitude, and phase of each component can be exactly calculated by using just 4m1 discrete values and its second-order derivatives. For a multifrequency complex signal, only 2m1 discrete values and its first-order derivatives are needed. The numerical experiments show that the proposed methods have very high resolution, and the sampling rate does not necessarily obey the Nyquist sampling theorem. With noisy signals, the proposed methods have extraordinary accuracy.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Information Processing submitted time 2021-09-10
Abstract: The geostationary optical remote sensing satellite has the advantages of high temporal resolution and wide coverage, which can continuously track and observe ship targets on the sea in a large range. However, the ship targets in geostationary satellite remote sensing image are usually small and weak, and are easily affected by cloud, island and other factors, which brings great difficulty to the detection of ship targets. This paper proposes a new method for detecting ships moving on the sea surface from geostationary optical remote sensing images: Firstly, the adaptive nonlinear gray stretch (ANGS) method is used to enhance the image to highlight the small and weak ship targets. Secondly, a multi-scale dual-neighbor difference contrast measure (MDDCM) method is designed to detect the position of the candidate ship target. Then, the shape characteristics of each candidate area is analyzed to remove false ship targets. Finally, the joint probability data association (JPDA) method is used for multi-frame data association and tracking. Experiments show that the proposed method can effectively detect and track moving ship targets in GF-4 satellite optical remote sensing images, and the method has better detection performance compared with other classical methods. "
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Radar Engineering submitted time 2020-09-08
Abstract: Monopulse lobing has been applied in scanning radars to improve image quality in the forward-looking area. However, monopulse measurements fail to resolve multiple targets in the same resolution bin because of angle glint, which may lead to imaging blurring. To tackle the problem, we propose a monopulse forward-looking imaging method via Doppler estimates of sum-difference measurements. Firstly, target multiplicity is resolved by exploiting the different Doppler slopes caused by relative motion between the platform and targets at different directions. Secondly, the azimuthal angles of the Doppler estimates are accurately measured by using sum-difference amplitude comparison (SDAC). Subsequently, the intensity of the sum channel estimates is projected onto the image plane according to the range and angle measurements. To further improve the precision of angle measurements, a chirp-z transform (CZT) based algorithm is proposed to reconstruct the Doppler estimates of sum-difference channels. Simulation results demonstrate the capability of our proposed methods to resolve multiple targets at the large-squint scanning angles. Real data experiments validate that the CZT based algorithm significantly improves the profile of the scene compared to that of the traditional monopulse imaging method. "
Peer Review Status:Awaiting Review