In this paper, we proposed a novel approach to estimate target 3-D velocity based on InISAR system with orthogonal baselines. For targets with slow maneuverability, the target movement can be approximated to uniform l...
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ISBN:
(数字)9780996007894
ISBN:
(纸本)9781728146331
In this paper, we proposed a novel approach to estimate target 3-D velocity based on InISAR system with orthogonal baselines. For targets with slow maneuverability, the target movement can be approximated to uniform linear motion during a short coherent processing interval (CPI). By introducing SAR imaging method into ISAR and utilizing the projection relationship between target velocity and the orthogonal baselines, the proposed method can obtain target 3-D velocity without radar line of sight (LOS) information. Simulation analysis verified the effectiveness of the new approach.
To solve the problem of multiple Unmanned Aerial Vehicles (UAVs) with intermittent communication topologies simultaneously attack a stationary target, a time cooperative guidance law is studied in this paper. First, a...
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ISBN:
(纸本)9781728137933
To solve the problem of multiple Unmanned Aerial Vehicles (UAVs) with intermittent communication topologies simultaneously attack a stationary target, a time cooperative guidance law is studied in this paper. First, a novel time cooperative guidance model for multiple UAVs is constructed based on UAVs-target relative motion equations. Then, a cooperative guidance law is designed based on consensus theory, which can ensure multiple UAVs' impact times realize finite time consensus under intermittent topologies. After UAVs' impact times become to be the same, traditional PN guidance law is applied in all UAVs to guarantee that the UAVs can attack the target precisely without influencing the consensus of impact times. Finally, the validity of the proposed method is shown by numerical simulations.
Aiming at the problem of time inconsistency problem exposed in multi-aircrafts simulation system during executing cooperative mission, a control solution of time consistency has been proposed to realize the unity of t...
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Aiming at the problem of time inconsistency problem exposed in multi-aircrafts simulation system during executing cooperative mission, a control solution of time consistency has been proposed to realize the unity of time information. On the basis of thoroughly analyzing the components and features of system, the factors that affect time synchronization are summarized and classified. After embedding a hardware of time synchronization system, a control solution is devised to maintain time consistency. Time synchronization and delay compensation are achieved from two aspects of hardware and software, which provides technical support for the following development and verification of cooperative controltechnology based on multiaircrafts simulation system.
In this paper, a new optimal linear-quadratic guidance law with terminal acceleration constraints is proposed for intercepting maneuvering target. Because the angle of attack is approximately proportional to the norma...
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In this paper, a zero attracted Lorentzian (ZAL) algorithm is created for system identification applications. The proposed ZAL algorithm is realized by using l 1 -norm penalty on the Lorentzian-based cost function to ...
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ISBN:
(数字)9781728153049
ISBN:
(纸本)9781728153056
In this paper, a zero attracted Lorentzian (ZAL) algorithm is created for system identification applications. The proposed ZAL algorithm is realized by using l 1 -norm penalty on the Lorentzian-based cost function to exploit the sparseness of the existing nature signals. Moreover, a reweighting method is adopt to enhance the ability of the proposed ZAL algorithm, and the new algorithm is called as reweighting zero attracted Lorentzian (RZAL) algorithm. The proposed algorithms are presented briefly and investigated via computer simulations. The gotten results from the simulation demonstrate that the proposed algorithms are superior to the popular adaptive filtering algorithms under alpha-stable noise interference.
Collision avoidance is the primary problem to be solved in formation flight of multiple Unmanned aerial vehicles(UAVs). Firstly, a cooperative collision avoidance architecture of multiple UAVs is designed according to...
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This paper establishes a satellite network topology optimization model based on satellite orbital dynamics, establishes constraints from two aspects of satellite geometric visibility and satellite elevation constraint...
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This paper establishes a satellite network topology optimization model based on satellite orbital dynamics, establishes constraints from two aspects of satellite geometric visibility and satellite elevation constraints in the concept of inter-satellite links, and finally solves the above optimization problems by using simulated annealing algorithm, and presents a time-varying satellite network topology optimization method. In the actual simulation, we give a satellite network with multiple satellites and optimize it. The optimal solution of the network configuration is obtained, and a shortest inter-satellite transmission path from signal start star to signal termination star based on time-varying is solved. For this inter-satellite link, the connectivity of inter-satellite link and the fault tolerance of satellite network are analyzed, which proves the feasibility and validity of the optimization method.
Robust adaptive Kalman filter(RAKF) is a method that can not only compensate for the model errors but also resist the measurement outliers. The method reduces the influence of the measurement outliers on the filtering...
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Robust adaptive Kalman filter(RAKF) is a method that can not only compensate for the model errors but also resist the measurement outliers. The method reduces the influence of the measurement outliers on the filtering system by reducing the weight of the abnormal observation. After the processing of robust estimation, all the errors are attributed to the inaccuracy of the model. Since the robust estimation is not theoretically quantitative that it can only reduce the observation error to a certain extent, the remaining observation errors are compensated as the model errors, resulting in new estimation errors. To address this problem, a method for detecting the model error is proposed as a trigger condition for RAKF to compensate for the model error,and this constitutes an improved robust adaptive Kalman filter(IRAKF) algorithm. The new algorithm performs the model errors compensation stricter than the original method. The efficacy of the improved algorithm is demonstrated via a traffic running testing with GPS/INS tight integration navigation system. Simulation results indicate that the improved algorithm can effectively reduce the inaccurate adaptive procedure and obtain relatively accurate and stable filtering results.
The unmanned aerial vehicle(UAV) power system consists of components that provide flight power for the UAV, which mainly includes three parts: motor, electronic speed controller(ESC), and battery. Since the UAV always...
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ISBN:
(纸本)9781728137933
The unmanned aerial vehicle(UAV) power system consists of components that provide flight power for the UAV, which mainly includes three parts: motor, electronic speed controller(ESC), and battery. Since the UAV always operates in the open air, which requires high stability of the power system, the failure mode and effects analysis(FMEA) is particularly significant and it has been widely used to examine potential failures in systems or components. However, the traditional FMEA method has many unreasonable points. In order to better deal with the uncertainty and improve the stability of the UAV power system, we propose a FMEA method which is based on the generalized Dempster-Shafer structures, the failure modes are comprehensively analyzed and the risks are ranked by combining the characteristic information of risk factors with the generalized evidence theory. The new method can not only deal with the uncertainty of risk assessment, but also further improve the reliability of effects analysis. In addition, the FMEA experiment of the UAV power system is carried out in this paper. The experimental results show that the method is effective for practical applications.
The naturalness of the panoramic image is an important criterion for evaluating the result of image stitching. When the overlapping region of the image has a low-texture area, the alignment is hard to accomplish due t...
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The naturalness of the panoramic image is an important criterion for evaluating the result of image stitching. When the overlapping region of the image has a low-texture area, the alignment is hard to accomplish due to incorrect and inadequate feature point matching pairs, and the salient structures are easily destroyed due to the unreasonable position of the optimal seam. To solve the problem, we use line segment matching information to assist the alignment of low-texture regions and use superpixel segmentation regions to filter the unreliable point correspondences. An improved seam-finding algorithm is finally used to blend images together. The experimental results demonstrate that the proposed method can get more natural stitching results.
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