共查询到19条相似文献,搜索用时 46 毫秒
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本文对单频GPS系统中载波相位平滑伪距算法进行研究,改进了传统平滑器,以消弱电离层延迟影响为基础,设计获得影响平滑器的各个因素的方案,用软件实现该平滑器并且进行动态实验验证,证明了该平滑算法的可行性和有效性。 相似文献
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伪距和载波相位是接收机的两个基本距离测量值,两者既有明显区别,又呈互补特性。伪距测量值包含钟差、大气延迟等各种误差,但是它真实反应卫星与接收机之间的距离;载波相位测量值含有整周模糊度,但是它非常平滑,精度很高。此外,多径效应对码伪距测量值的影响也远远大于对载波相位测量值的影响。目前,业界通常采用载波平滑码伪距的方法整合码伪距和载波测量的优点,输出一种既无模糊度又相对平滑的伪距测量值。通过设定不同的平滑时间常数和添加电离层模型对载波平滑码伪距的平滑结果进行分析,从而评估滤波器在不同时间常数条件下的性能,最终为平滑时间常数的选择提供决策依据。 相似文献
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为了达到更加精确的定位结果,在地基增强系统中需要利用载波相位对码伪距进行平滑处理,在对现有平滑滤波器存在的问题进行分析的基础上,本文介绍了一种用于载波平滑码伪距的系统噪声误差自适应卡尔曼滤波方法,可以避免周跳导致的伪距平滑结果误差过大,并通过仿真对该方法性能进行了验证。 相似文献
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无论GPS接收机的射频和基带参考时钟是否同源,都不会影响伪距定位。然而,对于载波相位平滑伪距定位,本文的理论分析表明:在新增卫星时,射频和基带参考时钟不同源将使新增星和原有星的平滑伪距钟差产生偏差,进而导致大幅度定位误差。在时钟同源和不同源两种条件下,利用自研的GPS基带芯片“航芯2E”,开展了大量硬件实验,验证了理论分析的正确性。论文得出的载波相位平滑伪距定位的接收机其射频和基带参考时钟必须同源的结论,对于GPS射频和基带芯片的模块化、系列化的规划和设计具有指导意义。 相似文献
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针对VBR编码视频流传输时造成的资源需求的高可变性和资源利用的不平衡性,提出一个新颖算法BSBS-VBR(buffer sharing and bandwidth smoothing of VBR streams).通过提前计算并预取最小所需的视频数据量,使服务器以固定码率获取并传输VBR编码视频;使用间隔缓存策略,根据系统当前资源状态为新请求分配资源,并根据当前访问分布以及可用资源对已分配缓存进行动态调整,保持资源平衡分配.该算法可减少服务器资源的峰值需求,平滑资源使用,提高资源利用率,扩大可服务用户数量.通过实验进行了验证. 相似文献
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A spatial smoothing algorithm to decorrelate highly correlated sources for direction-of-arrival (DOA) estimation in narrowband problems is developed. The rate of decorrelation of the coherent sources is very low and sensitive to the signal-to-noise ratio (SNR) for sources with close DOAs. A method to enhance the signal (to remove the effects of the sensor noise) and to make the spatial smoothing robust with respect to SNR is proposed. This approach will significantly improve the resolution of the algorithm. Statistical characteristics of the improved spatial smoothing are compared with that of the standard spatial smoothing 相似文献
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Interframe coding techniques, such as those used in MPEG video, give rise to a sequence of encoded pictures whose sizes (in number of bits) differ by a factor of ten or more. Buffering is needed to reduce fluctuations in the rate at which video packets are sent to a network connection. We design and specify a lossless smoothing algorithm, characterized by three parameters: D (delay bound), X (number of pictures with known sizes), and H (lookahead interval). We prove a theorem which guarantees that, if K⩾1, the algorithm finds a solution that satisfies the delay bound. We present the algorithm's performance from a large number of experiments conducted using MPEG video traces. Lastly, we discuss algorithm implementation 相似文献
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Hermann Ney 《Signal processing》1983,5(2):163-173
This paper presents a smoothness optimization approach to the nonlinear smoothing problem. Linear smoothing techniques fail to provide adequate results for curves which exhibit both sharp discontinuities to be preserved and, due to measurement or processing errors, outliers and noise to be filtered out. The nonlinear algorithm is based on a criterion for the overall smoothness of the curve. The smoothness criterion is optimized by a dynamic programming strategy. The resulting algorithm turns out to be computationally attractive. The computation time grows proportionally to N2 and the storage requirements are 2N locations where N is the number of samples to be smoothed. The algorithm is applied to smoothing pitch contours. 相似文献
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For the tracking problem of multiple maneuvering targets in radar observation,the sequential Monte-Carlo cardinality-balanced multi-Bernoulli track-before-detect (SMC-CBMeMBer-TBD) algorithm is inaccurate in the estimation of the number of targets and the precision of state estimation.An improved algorithm based on SMC-CBMeMBer forward backward smoothing track-before-detect algorithm was proposed.In the algorithm,the multi target particle swarm optimization (MOPSO) was added between the process of prediction and update,and the fitness function was set up based on the observation value to make the particle set move to the position of the larger posterior probability density distribution,and solve the particle poverty in the heavy sampling process.In the update step,the algorithm was used.Then the smoothing recursive method was added,and the arithmetic operation time was prolonged,but the number and the state estimation precision were improved.The simulation results show that compared with the CBMeMBer-TBD method,the proposed algorithm improves the accuracy of the estimation of the number of maneuvering targets and the accuracy of the target state estimation. 相似文献
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为了抑制米散射大气探测激光雷达回波噪声引起的信号随机波动,采用新设计的自适应分段平滑方法对信号进行平滑处理。根据激光雷达信号特性,信号有效变化幅值大于信号背景噪声波动。以背景噪声标准差的若干倍表示信号的噪声幅度。按照相邻信号幅值差与噪声幅度的对比,可以确定信号发生有效变化的位置,这些位置可以作为信号分段端点,在分段端点内用滑动平均可以实现对信号的自动分段平滑。用实测微脉冲激光雷达信号对方法进行了验证,并与常用固定分段平滑方法进行了对比。结果表明,自适应分段平滑方法可以根据信号变化的剧烈程度自动选择平滑窗口大小,在对噪声进行有效抑制的同时,避免平滑过度造成的信号畸变。 相似文献