共查询到19条相似文献，搜索用时 140 毫秒
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双频雷达高度计电离层色散效应误差分析 总被引：1，自引：0，他引：1
由于现代星载雷达高度计采用了脉冲压缩技术，引入了电离层色散误差，在双频高度计的低频段该误差更明显。本文基于全去斜技术的理论模型，推导了这项误差的机理，提出可以把该误差等效为二次相位误差，并结合具体参数给出了分析的结果。本文还讨论了Chirp信号的多普勒误差对测高的影响。最后，作者通过计算机仿真得到了电离层色散效应对系统点目标响应的影响,对前面的结论进行了验证。 相似文献
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为了实现自主移动机器人在室内的精准定位,提出了一种对运动姿态求解过程进行优化且基于特征点匹配的双目视觉定位算法。首先,利用FAST算子提取左右相机采集图像的特征点,并通过BRIEF算子进行特征点匹配;然后,对前后帧图像中的特征点采用BRIEF算子进行特征跟踪,并通过RANSAC方法过滤掉误匹配的特征点;最后,对帧间运动估计求解位姿的过程进行了优化,通过满足匹配要求的间隔最大的两帧图像求解位姿,以减小帧间运动估计产生的累积误差。实验结果表明,在机器人运动缓慢的情况下,该算法有效地减小了帧间运动估计产生的累积误差,提高了定位精度,并基本实现了在室内的定位。 相似文献
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本文首先介绍了星载SAR回波信号仿真相关技术,包括星地空间几何模型、回波信号数学模型和距离频域脉冲相干法。在此基础上给出了一种星载SAR回波信号仿真方案,并详细给出了其仿真算法流程。然后通过对仿真算法流程的并行性分析,以并行编程标准OpenMP为基础对仿真算法进行了并行化。仿真实验结果证明了并行仿真算法的正确性和高效性。 相似文献
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姿态矩阵的更新算法优劣直接影响了捷联惯性导航系统(strapdown inertialnavigation system,SINS)的精度。本文针对以光纤陀螺为代表的输出为角速度的捷联惯导系统,研究了其姿态解算算法,对欧拉角法、方向余弦法,四元数毕卡解法、四元数龙格库塔解法、基于角速度的优化等效旋转矢量法进行了分析,并对后三种方法在三轴摇摆条件下进行了仿真。本文对光纤捷联惯导系统的姿态算法研究具有重要的意义。 相似文献
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智能电动两轮平衡车的稳定性很大程度上取决于车体姿态信息检测的准确性。为解决低成本传感器测量精度不高的问题,实现对平衡车俯仰角和横滚角的高精度测量,本文采用卡尔曼滤波算法,利用加速度计所解算的姿态角建立观测方程,利用陀螺仪输出的角速度建立状态预测方程,建立卡尔曼滤波器,实现陀螺仪和加速度两传感器数据的融合,最终完成对平衡车姿态角的估计。 相似文献
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采用阵列天线的微波成像系统会产生多通道幅相不一致性问题.针对使用阵列天线进行微波成像的应用,将回波模型中的多通道相位误差分为距离偏移误差和残余常数相位误差,并分析其对成像造成的影响,研究了使用回波中选定参考点目标进行相位误差校正的方法.最后通过微波成像国家重点实验室开发的地基实验系统数据验证了我们的分析和结论. 相似文献
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本文针对两坐标搜索雷达,通过分析原始回波数据的特性,提出了一种有效的点迹凝聚算法,并对算法进行了软件实现,经过测试和实地验证,该算法可以满足搜索雷达系统数据处理的性能要求和实时性要求。 相似文献
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在全球气候变暖的背景下湖泊变化已是国内外地学界关注的环境问题,并日益受到各国政府和研究机构的重视。本文以长江中下游的6个典型湖泊为研究对象,基于2003年-2009年ICESat—GLAS测高数据,采用高斯滤波法对ICESat—GLAS测高数据所对应的回波进行去噪后,用于识别水体与陆地;采用融合算法从LandsatTM影像数据提取湖泊边界;提取湖泊边界内的ICESat—GLAS水位观测值构建了湖泊的年际和年内水位变化,进一步分析了6个湖泊的水位变化时空特征与原因。结果表明：从LandsatTM中提取湖泊边界的精度达到10m,ICESat—GLAS测高数据推算出洪泽湖蒋坝站、洞庭湖城陵矾站、鄱阳湖星子站和都昌站、太湖西山观测站、巢湖闸站和高邮湖高邮站的ICESat测高数据验证的平均精度分别为-3．9cm、-8．3cm、-9．0cm、-2．5cm、-3．1cm和-4．1cm;在整个观测期间,长江中下游流域的湖泊水位呈周期性波动,但较历史观测资料,湖泊平均水位有所降低,且自2006年10月以后三峡工程对洞庭湖的水位调控明显。 相似文献
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The fast affine projection (FAP) algorithm (Gay and Tavathia, Proceedings of the IEEE International Conference on Acoustic, Speech and Signal Processing, 1995, 3023) is known to outperform the NLMS with a slight increase in complexity, but it involves the fast calculation of the inverse of a covariance matrix of the input data that could undermine the performance of the algorithm. The block subband adaptive algorithm in (Courville and Duhamel, IEEE Trans. Signal Processing 46(9) (1998) 2359) has also illustrated significant improvement in performance over the NLMS and other frequency domain adaptive algorithms. However, it is known that block processing algorithms have lower tracking capabilities than the their sample-by-sample counterparts. In this paper, we present a sample-by-sample version of the algorithm in (Courville and Duhamel, IEEE Trans. Signal Processing 46(9) (1998) 2359) and develop a low complexity implementation of this algorithm. As a sample-by-sample algorithm, it avoids the reduced tracking capability of block algorithms. Because it does not use matrix inversion, it avoids the numerical problems of FAP algorithms. We will show that the new sample-by-sample algorithm approximates the affine projection algorithm and possesses a similar property in reducing coefficient bias that appears in monophonic and stereophonic teleconferencing when the receiving room impulse responses are undermodeled. The new fast sample-by-sample algorithm is extended for stereo acoustic echo cancellation. Simulations of echo cancellations in actual rooms are presented to verify our findings. 相似文献
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《Journal of The Franklin Institute》2021,358(18):9909-9928
In this paper, the finite horizon tracking control problem of probabilistic Boolean control networks (PBCNs) is studied. For a given reference output trajectory, two trackability definitions are introduced according to whether the tracking probability is 1. Under the framework of the semi-tensor product, some necessary and sufficient conditions are obtained to determine whether the reference output trajectory is trackable with probability (probability one) by a PBCN starting from a given initial state. Based on this, two algorithms are proposed to determine the maximum tracking probability and the corresponding optimal control policy sequence. By determining the tracking error of the reference output trajectory, two related optimal control problems are considered: one is to minimize the expected value of the total tracking error, and the other is to minimize the maximum tracking error. Inspired by dynamic programming, corresponding algorithms are given to solve these two problems. Finally, two examples are given to verify the validity and correctness of the results. 相似文献
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Ming-Feng Ge Cai-Hua Xiong Zhi-Wei Liu Jie Liu Xiao-Wen Zhao 《Journal of The Franklin Institute》2017,354(13):5646-5666
This paper mainly focuses on two classes of coordinated tracking problems for networked robotic systems, including semi-global coordinated tracking (SCT) problem and global coordinated tracking (GCT) problem. Considering that the dynamics of the networked robotic system can be unattainable, several novel model-free controller-estimator algorithms are proposed to solve the SCT and GCT problems, as well as to reject the input disturbances contained in the system dynamics. By invoking nonsmooth analysis and Lyapunov argument, a number of novel criteria (including sufficient criteria, necessary and sufficient criteria) for semi-global and global asymptotic stability of the presented algorithms are established. Finally, simulation experiments are carried out to verify the theoretical results. 相似文献
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超声波发生器根据应用场合的不同,而要求有不同的电路设计方案,文章作者设计了一款应用于半导体焊线设备的超声波发生器的信号源电路,该电路采用英特矽尔公司生产的icl8038芯片,利用该芯片设计了一款高精度的波形发生器,通过选择不同电阻,电容等外部元器件,其设计的频率范围可以从0.001Hz到300KHz,并且也可以通过外部电压的扫描来产生不同频率的波形。文章作者用Proteus仿真软件对ICL8038芯片所设计的信号源电路进行了仿真。 相似文献
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《Journal of The Franklin Institute》2022,359(5):2377-2402
Distributed target tracking is an important problem in sensor networks (SNs). In this paper, the problem of distributed target tracking is addressed under cyber-attacks for targets with discrete-time and continuous-time nonlinear dynamics. Two distributed filters are obtained for every node of the SN to estimate the states of a general class of nonlinear targets which can be seen in many practical applications. Compared with the existing results in the literature, the network topology of the SN is assumed to be subjected to the denial-of-service attack such that the communication links among sensor nodes are paralyzed or destroyed by this kind of attack. Moreover, the proposed algorithms are designed based on an event-triggered communication strategy that means the frequency of information transmission and unnecessary resource consumption are significantly reduced. The presented algorithms’ stability is also analyzed in the presence of noise to achieve secure event-triggered target tracking in mean-square. Two simulation examples are utilized to demonstrate the efficiency of the proposed event-triggered algorithms. 相似文献
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《Journal of The Franklin Institute》2022,359(17):10172-10205
Recently, the sparsity-aware sign subband adaptive filter algorithm with individual-weighting-factors (S-IWF-SSAF) was devised. To accomplish performance enhancement, the variable parameter S-IWF-SSAF (VP-S-IWF-SSAF) algorithm was developed through optimizing the step-size and penalty factor, respectively. Different from the optimization scheme, we devise a family of variable step-size strategy S-IWF-SSAF (VSS-S-IWF-SSAF) algorithms based on the transient model of algorithms via minimizing the mean-square deviation (MSD) on each iteration with some reasonable and frequently adopted assumptions and Price's theorem. And in order to enhance the tracking capability, an effective reset mechanism is also incorporated into the proposed algorithms. It is worth mentioning that the presented algorithms could acquire lower computational requirements and exhibit higher steady-state estimation accuracy obviously and acceptable tracking characteristic in comparison to the VP-S-IWF-SSAF algorithm. In addition, the stable step-size range in the mean and mean square sense and steady-state performance are concluded. And the computational requirements are exhibited as well. Monte-Carlo simulations for system identification and adaptive echo cancellation applications certify the proposed algorithms acquire superior performance in contrast to other related algorithms within various system inputs under impulsive interference environments. 相似文献
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《Journal of The Franklin Institute》2021,358(13):6508-6525
For multi-agent system (MAS), most of existing iterative learning control (ILC) algorithms consider about the tracking of reference defined over the whole trial interval, while the point-to-point (P2P) task, where the emphasis is placed on the tracking of intermediate time points, has not been explored. Thus, a distributed ILC method is proposed, in which each agent updates the feedforward control input by learning from the experience of itself and its neighbors in previous repeated tasks to achieve the goal of improving performance. In addition, for the sake of reducing the burden of data transmission in MAS, effective data quantization is essential. In this case, the quantitative measurement of the error of the tracking time points is further used in the ILC updating law. In order to accommodate this requirement, a distributed point-to-point iterative learning control (P2PILC) with tracking error quantization for MAS is first proposed in this paper. A necessary and sufficient condition is presented for the asymptotical stability of the proposed algorithm, and simulation results show the effectiveness of it finally. 相似文献