共查询到19条相似文献,搜索用时 46 毫秒
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本文介绍了基于星载GNSS观测数据的低轨卫星精密定轨和轨道精度评估方法,并基于GRACE卫星的实测数据开展定轨试验。分析结果表明,基于星载GNSS的动力学定轨可获取厘米级的卫星轨道,为未来低轨星座的精密轨道确定提供参考。 相似文献
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提出了一种利用星间距离信息和扩展卡尔曼滤波算法确定卫星的位置和速度的方法。利用STK软件建立GPS星座,将1颗目标卫星与3颗参考卫星之间的距离引入一定的误差作为星间观测值,利用扩展卡尔曼滤波算法实现卫星的自主定轨。并对算法进行了改进,利用几何准确度因子GDOP值控制参考卫星的选择,消除了误差峰值。运算结果表明改进后的算法有很好的收敛性,提高了定轨准确度。 相似文献
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星载GPS定轨中精密GPS卫星钟差的改正和应用 总被引:1,自引:0,他引:1
低轨道卫星星载GPS精密定轨的最主要的误差源是在SA影响下GPS卫星钟的高频抖动。为了克服这一误差,本文分析了在SA影响下GPS卫星钟差变化的特性,探讨了利用GPS地面跟踪站的观测数据估算GPS卫星钟的可行性,建立了相应的算法和软件系统,并把由地面跟踪站的实测数据估算的GPS卫星钟差应用于星载GPS定轨计算,得到1m的定轨精度。 相似文献
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针对低轨卫星实时定轨过程中滤波初值及轨道模型不精确导致定轨精度降低的问题, 提出一种带摄动力拟合的强跟踪容积卡尔曼滤波(Strong Tracking Cubature Kalman Filter, STCKF)算法.通过强跟踪滤波(Strong Tracking Filter, STF)的等价表示计算次优渐消因子以在线实时调整增益矩阵, 强迫残差序列相互正交, 有效降低了对初始状态的敏感性.使用欧拉预测校正法对带J2项摄动的轨道动力学方程进行离散, 用多项式拟合函数表示其余摄动力以提高模型精度.仿真结果表明, 带摄动力拟合的STCKF算法可以有效提高实时定轨精度, 并且降低了定轨精度对滤波初值的依赖. 相似文献
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The central unit of a Viterbi decoder is a data-dependent feedback loop which performs an add-compare-select (ACS) operation. This nonlinear recursion is the only bottleneck for a high-speed parallel implementation. A linear scale solution (architecture) is presented which allows the implementation of the Viterbi algorithm (VA) despite the fact that it contains a data-dependent decision feedback loop. For a fixed processing speed it allows a linear speedup in the throughput rate by a linear increase in hardware complexity. A systolic array implementation is discussed for the add-compare-select unit of the VA. The implementation of the survivor memory is considered. The method for implementing the algorithm is based on its underlying finite state feature. Thus, it is possible to transfer this method to other types of algorithms which contain a data-dependent feedback loop and have a finite state property 相似文献
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In this paper, a parallel Surface Extraction from Binary Volumes with Higher-Order Smoothness (SEBVHOS) algorithm is proposed
to accelerate the SEBVHOS execution. The original SEBVHOS algorithm is parallelized first, and then several performance optimization
techniques which are loop optimization, cache optimization, false sharing optimization, synchronization overhead optimization,
and thread affinity optimization, are used to improve the implementation’s performance on multi-core systems. The performance
of the parallel SEBVHOS algorithm is analyzed on a dual-core system. The experimental results show that the parallel SEBVHOS
algorithm achieves an average of 1.86x speedup. More importantly, our method does not come with additional aliasing artifacts,
comparing to the original SEBVHOS algorithm. 相似文献
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PRANAY CHAUDHURI 《International Journal of Electronics》2013,100(6):925-930
A parallel algorithm for analysing activity networks is presented that works on a tree-structured parallel computer. The time complexity of the algorithm is 0(n 2/ p + n log p) with p (1 ≤ p ≤ n) processors for an activity network with n events (nodes). It is shown that the cost of this algorithm, which is the product of the parallel running time and the number of processors used, is less than that of each of the existing parallel algorithms for the same problem by at least a factor of n. 相似文献
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The authors present a parallel algorithm for fast rendering. A set of zones which can be concurrently processed is identified; this set is split into a number of subsets equal to the number of available processors. Each processor renders, in parallel with the others, a zone of its set 相似文献
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两层异构网络中出现的小区间干扰协调是当前异构网络干扰问题研究的热点。针对软件实现增强小区调度几乎空白子帧(ABS)的干扰方案存在处理数据量大、速度慢的缺点,基于可重构阵列结构提出了一种动态ABS干扰协调的并行化硬件实现方案。该算法在增强小区内根据用户数动态分配ABS比例,以改善小区边缘用户的信道容量,通过流水线的方式使用多个轻核处理元(PE)实现并行计算以提高运算效率。测试结果表明,使用12个PE同时调度实现算法的映射,运行1983个周期,其性能比单个PE提升77.03%,该算法的并行计算能力得到显著提升,宏基站用户的吞吐量可以达到4.76 Mbit/s. 相似文献