共查询到19条相似文献，搜索用时 310 毫秒
1.
登陆台风的多层递阶预报 总被引：1，自引：0，他引：1
多层递阶预报是动态系统的新型统计预报理论。由于它把动态系统看成是一个时变参数系统,因而与客观实际较为符合,预报误差也相对较小,利用它来进行台风预报具有一定的实用价值。 相似文献
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对GPS定位中的SA误差作了系统辨识。表明：SA误差可用时变AR（p）模型表述，AR（p）的时变参数可由RLS算法结合F判据建立的AR（p）模型辨识机获得。用该方法获得的模型对SA误差进行预报。在剔除野值后精度在10m之内。还提出了一种将以AR（p）模型表述的SA误差加入GPSKALMAN滤波器的方法，可得到一种具有SA预报能力的GPSKALMAN滤波器。 相似文献
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针对传统变分贝叶斯自适应滤波中,基于经验选取常值遗忘因子,不能自适应时变量测噪声的问题,提出一种基于可变因子的变分贝叶斯自适应滤波,并应用于船载捷联惯性导航系统(strapdown inertial navigation system, SINS)动态对准。首先利用变分贝叶斯方法近似噪声的后验分布,估计时变量测噪声和状态向量后验分布。其次通过噪声方差时变强度构造可变因子,实现自适应调整变分贝叶斯参数。最后给出了基于可变因子的GNSS/SINS海上动基座对准流程及算法。船载实测数据表明,所提算法在时变方差下,较卡尔曼滤波和传统贝叶斯滤波方位角误差收敛到0.5°范围内所需时间分别缩短了52%和44%;横滚角和方位角均方根误差分别降低57%、46%和13%、9%;东向和北向速度均方根误差分别降低56%、68%和51%、22%。 相似文献
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针对多通道乘性噪声系统问题的实际需要 ,推广 Rajasekaran滤波算法 ,利用线性最小方差的概念和投影公式 ,导出含有乘性噪声统计特性参数阵特殊乘法运算的新息协方差矩阵 ,并利用这个中间矩阵 ,在观测为多通道 ,且各个通道的乘性噪声不同 ,以及系统的动态噪声和观测噪声同时刻相关的情况下 ,导出状态递推滤波算法 ,该算法在线性最小方差意义下是最优的。并对该算法进行仿真研究 ,仿真结果表明了该算法的有效性 相似文献
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最优平滑及最优反褶积在石油地震勘探、通讯工程、语音处理等应用领域都具有十分重要的意义。以往的带乘性噪声系统的平滑及反褶积大都对系统模型的噪声特性有着较强的限制条件 ,要求动态噪声及观测噪声互相独立或只能在同时刻相关。该文给出了一种在动态噪声为有色噪声及动态噪声和量测噪声在有限时间段上相关的情形下带乘性噪声系统的固定域平滑及反褶积算法 ,该算法在线性最小方差意义下是最优的。通过仿真计算 ,说明了该算法的有效性。 相似文献
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针对石油地震勘、通讯工程、语言处理等应用领域 ,该文研究一种在更弱的噪声限制条件下带乘性噪声系统的状态最优滤波 ,就动态噪声为有色噪声及动态噪声和量测噪声在有限时间段上相关的情形 ,给出了线性最小方差意义下的状态最优滤波算法 ,并对此算法作了仿真计算 ,获得满意的结果 相似文献
7.
带乘性噪声系统的极大似然最优估计算法 总被引：1，自引：1，他引：0
对带乘性噪声系统（ＳＭＮ）在乘性噪声及其统计参数未知的情况下,基于极大似然准则,提出了一种分块组合优化估计算法（ＢＣＯＥＡ）。该算法不需要事先知道乘性噪声的统计参数,可同时进行状态最优估计以及乘性噪声序列和其统计参数的最优估计。 相似文献
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水声信道具有复杂随机时变特性并存在严重的多径时延、能量损失和畸变等因素,使得水声信道的建模和估计一直是学界的难点问题。本文基于复杂多通道带乘性噪声模型来刻画随机时变的水声信道,在信道建模基础上利用最优滤波递推算法实现发送字符的估计。该算法在线性最小方差意义下是最优的,能有效克服码间干扰和噪声污染。所建立的信道模型能够刻画复杂快变的水声信道,对应的最优信道估计算法具有计算量小的优点,能够动态跟踪信道增益的随机变化。仿真结果验证了本文算法的有效性。 相似文献
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针对带乘性噪声广义系统,提出1种在线性最小方差意义下的状态最优估计算法.首先,采用标准分解将系统变换为2个子系统;其次,通过估计子系统的状态,获得原系统的状态最优滤波.同时,算法还给出了动态噪声与量测噪声的估计.仿真结果表明了该算法的有效性. 相似文献
10.
带乘性噪声系统由于其广泛的适用性,一直成为研究的热点。针对带乘性噪声系统的鲁棒状态估计算法进行研究,利用线性矩阵不等式的方法,讨论状态方程中含有范数有界不确定性参数的带乘性噪声系统的方差约束鲁棒状态估计器存在的条件,并针对此类带乘性噪声系统推导出1套方差约束鲁棒状态估计算法以及最优方差约束鲁棒状态估计算法。仿真结果验证算法的有效性。 相似文献
11.
The detection of known and partially known signals in additive white Gaussian uonstationary noise is considered, with primary attention to the ease where the time-varying noise intensity parameter N_{o}(t) is a periodic function. Optimum receiver structures are derived for three detection cases, namely completely known signals, sinusoids with random phase, and sinusoids with both random amplitude and phase. It is demonstrated that optimum receiver performance can be achieved only if proper synchronization to the noise intensity N_{o}(t) is accomplished. Large performance penalties can be demonstrated when an improperly synchronized receiver is used. Consequently, suboptimum receivers that ignore the noise intensity time variations and therefore require no synchronization, have been considered, and their performance compared to their optimum counterparts. Depending on the type of time-varying noise intensity being considered, results show that performance differences between optimum and suboptimum receivers can be negligible in some cases, and yet can be substantial in other cases. Several examples have been worked out using two different forms for N_{o}(t) and corresponding performance evaluations have been carried out and presented graphically in terms of receiver error probability as a function of signal-to-noise ratio. 相似文献
12.
海上油田油轮外输系统优化分析 总被引：2，自引：0，他引：2
对海上油田油轮外输系统进行了分析 ,建立了系统优化的数学模型。选用模矢搜索法、单纯形算法和模拟退火算法三种优化方法进行了计算 ,得出在对某些非线性问题进行优化时 ,利用模拟退火算法和直接最优化方法 (如单纯形法 )相结合 ,既能保证得到全局最优解 ,又能减少计算时间。通过实例计算 ,得出油轮外输系统适用于离岸距离较远、产量较小的油田 ,其外输费用随离岸距离的增加变化非常小 ,但随油田产量的增加而增加较大 相似文献
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针对带乘性噪声的一类非线性系统,给出了1种带单重渐消因子的强跟踪状态滤波算法。该算法将非线性系统线性化后,采用了线性最小方差估计方法来进行状态估计,通过运用正交原理和引入渐消因子,使得滤波效果具有强跟踪的优良性能。该算法扩展了卡尔曼滤波在带乘性噪声非线性系统状态估计中的应用范围。仿真结果表明了该算法的有效性。 相似文献
15.
储层沉积微相是影响储层非均质性的重要因素之一,准确预测储层沉积微相分布对认识储层非均质性、提高油田油气采收率具有重要意义.储层随机建模方法具有很强的地质适用性,合理选择随机建模方法能够有效提高模型精度.以东濮凹陷濮城油田沙三中亚段6-10水下扇油藏为例,由于水下扇沉积储层微相具有几何构型及空间分布复杂的特点,选择序贯指示建模可以对不同微相采用不同变差函数来表征其空间分布结构特征,从而再现储层微相复杂的空间分布.通过定义沟道吻合程度参数Mat对模拟实现进行检验,抽稀井沟道吻合程度参数Mat平均值达到84.7%,表明建模结果具有较高的准确度.序贯指示建模适合于建立水下扇储层沉积微相模型. 相似文献
16.
Reliable,with high data rate,acoustic communication in time-varying,multipath shallow water environment is a hot research topic recently.Passive time reversal communication has shown promising results in improvement of the system performance.In multiuser environment,the system performance is significantly degraded due to the interference among different users.Passive time reversal can reduce such interference by minimizing the cross-correlated version of channel impulse response among users,which can be realized by the well-separated users in depth.But this method also has its shortcomings,even with the absence of relative motion,the minimization sometimes may be impossible because of the time-varying environment.Therefore in order to avoid the limitation of minimizing the cross-correlated channel function,an approach of passive time reversal based on space-time block coding (STBC) is presented in this paper.In addition,a single channel equalizer is used as a post processing technique to reduce the residual symbol interference.Experimental results at 13 kHz with 2 kHz bandwidth demonstrate that this method has better performance to decrease bit error rate and improve signal to noise ratio,compared with passive time reversal alone or passive time reversal combined with equalization. 相似文献
17.
The application of a neural network controller to remotely operated vehicles (ROVs) is described. Three learning algorithms for online implementation of a neural net controller are discussed with a critic equation. These control schemes do not require any information about the system dynamics except an estimate of the inertia terms. Selection of the number of layers in the neural network, the number of neurons in the hidden layer, initial weights for the network and the critic coefficient were done based on the results of preliminary tests. The performances of the three learning algorithms were compared by computer simulation. The effectiveness of the neural net controller in handling time-varying parameters and random noise is shown by a case study of the ROV system 相似文献
18.
带乘性噪声系统由于其广泛的适用性,一直成为研究的热点。针对带乘性噪声系统状态最优估计的自适应算法进行研究,探讨在噪声服从平稳正态分布情况下,对未知动态噪声方差阵与观测噪声方差阵的辨识问题。在证明带乘性噪声系统新息在稳态时和线性系统新息有着相似稳定特性的前提下,通过对线性系统辨识方法的改进,完成对带乘性噪声系统噪声方差阵的辨识,并利用新息特性对该方法进行进一步改进,以提高辨识精度;最后通过仿真验证该方法的有效性。 相似文献
19.
水体石油类物质生物-光学遥感反演模型 总被引：2，自引：1，他引：1
A biooptical modeling, which is based on a radiation transfer model, can be employed to simultaneously retrieve the concentration of various colour factors by multi-spectral remote sensing data, after connecting inherent optical properties （absorption coefficient and backward scattering coefficient） of colour factor with apparent optical properties （remote sensing reflectivity）. At present, this method has been used in a relatively wide range of applications in the inversion of a conventional water colour factor concentration in the case II water body： applications such as chlorophyll, suspended sediment, yellow substance. On the basis of extensive field testing data of water quality, correspondingly apparent optical properties, and the full use of the existing parametric model of colour factor inherent optical properties （with the parametrization of petroleum substance inherent optical properties established in the project） the remote recognition model for oil concentration is established by introducing oil as a new water co/our factor into a biooptical remote algorithm. The estimated value of the oil concentration was obtained by solving the biooptical model, using the data measured in May 2008 and August 2009 and June 2010 in seawater. The highly accurate inversion result promises to estimate the oil concentration in water for remote sensing. 相似文献