锥扫型光学传感器像平面多目标轨迹跟踪

积分概率多假设跟踪(IPMHT)是一种基于期望极大化(EM)的准最优贝叶斯多目标迭代跟踪算法,研究了该算法在锥扫型光学传感器像平面多目标轨迹跟踪中的问题。为提高算法的跟踪性能和计算效率,利用逻辑概率数据关联滤波(PDAF)方法进行目标初始状态估计,并利用目标幅度信息和波门技术对IPMHT进行优化。针对锥扫型传感器非线性观测下的多目标跟踪,将扩展无味卡尔曼滤波(AUKF)与优化的IPMHT算法相结合,实现像平面多目标轨迹的起始、维持和终结。蒙特卡洛仿真实验表明,该算法成功地解决了锥扫型传感器的像平面多目标轨迹跟踪问题,在提高目标跟踪性能的同时改善了计算效率。     

基于IMM-PF的再入目标数据融合算法与仿真

为了提高弹道再入目标的跟踪精确度,提出了一种基于交互式多模型粒子滤波（IMM-PF）的再入目标数据融合算法。该算法将交互式多模型和粒子滤波相结合,用有限个运动模型来逼近再入目标的运动状态,在对再入目标的运动方程和观测方程离散处理的基础上,采用粒子滤波算法计算各模型的状态估计值和协方差,并采用残差重采样方法克服了粒子权重的退化问题;在粒子滤波过程中,系统不断改善粒子的概率密度函数,不断更新各个模型的概率,从而实现对再入目标跟踪中未知参数的精确估计。通过实例仿真表明：与其他算法相比,该算法的跟踪精确度较高,运行时间较短,算法收敛性较好,适合对再入目标的快速、精确跟踪。     

基于核密度杂波估计的改进MHT算法

传统多假设跟踪(Multiple Hypothesis Tracker, MHT)算法假定杂波强度先验已知,在未知杂波的观测场景中,杂波强度误差将导致数据关联的准确性急剧下降。针对这一问题,本文提出一种基于核密度估计(Kernel Density Estimation, KDE)的在线杂波估计MHT算法。首先利用核密度函数拟合未知的杂波密度函数,并自适应地估计出该时刻波门内的杂波强度;然后利用杂波强度估计值计算假设航迹的得分函数,提高了数据关联的准确性和目标跟踪的稳定性。仿真结果表明,在未知杂波观测场景中,MHT-KDE算法有效改善了航迹的连续性,减少了虚假航迹数。      

一种基于随机集的PHD多目标多传感器关联算法

针对复杂电磁环境下的多目标关联计算量大、准确率低的问题,提出了一种基于随机集概率假设密度(PHD)的多目标多传感器关联算法。该方法首先采用高斯混合PHD(GMPHD)对多传感器的量测信息进行滤波,再对滤波结果做最近邻数据关联处理,从而得到多目标航迹。杂波环境下的仿真实验表明,该方法在保证滤波精度的同时,能够有效降低运算量,提高数据关联的准确度。     

一种基于混合MCMC的时域波达方向估计算法

基于马尔科夫链蒙特卡洛（Markov Chain Monte Carlo,MCMC）方法的时域波达方向估计算法通过构造马尔科夫链的方式来对波达方向进行估计,但是现有的算法在马尔科夫链的收敛速度和结果上并没有表现出很好的鲁棒性。为了优化算法的性能,采用多(短)链并行的方式代替原来的长链生成方式,提高了算法收敛的稳定性;并对特定模型下的构造过程进行分析,优化了状态空间,提高了算法的搜索效率;同时结合多混合的MCMC方法,进一步提高了算法估计的精确度和收敛速度。仿真结果表明,改进后的算法对波达方向估计的准确性和实时性都有很大提升。     

基于自适应GMM杂波估计的改进MHT算法

在传统多假设跟踪(MHT)算法中通常会假设杂波强度先验已知,当观测场景中杂波未知且空变时,该假设将会导致跟踪算法性能急剧下降。针对这一问题,本文提出一种基于自适应高斯混合模型(GMM)在线估计未知杂波的改进MHT算法。首先利用自适应GMM拟合未知杂波空间分布,并自适应地估计出波门内的杂波强度;然后将其应用于MHT处理中,有效改善航迹得分计算和最优假设航迹估计的准确性,进而实现在杂波未知场景中的稳定跟踪。仿真结果表明,在未知杂波观测场景中,所提算法相比传统MHT算法和MHT-GMM算法获得了更好的数据关联准确性和航迹维持性能。     

基于多假设的多平台多目标数据关联方法

本文研究了一种面向航迹的多平台多假设数据关联算法，包括航迹树的构建、航迹得分计算、序列概率比检验、假设生成以及分支航迹剪枝等，在此基础上针对实装环境下点迹量大、虚假目标多的问题对算法进行了改进优化，并进行了仿真验证。     

基于弹道目标的发射事件管理技术研究

弹道导弹在整个飞行过程中具有多种飞行状态,同时在每个飞行阶段会产生弹头、弹体以及其他伴飞物;当进行多枚弹道导弹齐射时,将产生大量的数据,其结果为数据处理中心准确获取导弹发射次数、目标航迹数据处理和为武器系统拦截提供有效拦截目标产生巨大不确定因素。因此,通过开展发射事件管理技术研究,可以有效解决以上问题。该技术 通过时间-空间关联算法、导弹定轨关联算法和导弹分离事件关联算法,实现对空间中不同目标进行关联,将属于同一发射事件的不同目标关联为同一次发射事件,并给出同一发射事件中的主目标,为目标识别系统和武器系统进行重点目标识别和拦截提供重要支撑。试验结果表明了该技术的有效性。     

一种具有自适应关联门的杂波中机动目标跟踪算法

针对杂波环境下的机动目标跟踪,该文提出一种基于自适应关联门的跟踪算法。该算法以传统交互多模型概率数据关联算法为基础,在关联门内无有效量测点迹时,假设目标在前一滤波时刻或是更早时刻以最大机动水平改变原运动模式,利用该假设条件下所获得的目标预测量测及当前真实预测量测,对用于确定关联门的新息协方差进行修正,使得关联门逐步适当扩大,以尽可能地包含目标真实量测点迹。仿真结果表明,自适应关联门跟踪算法能在不影响跟踪精度和算法运算量的情况下,有效降低机动目标的跟踪丢失概率。     

一种多普勒盲区条件下的多假设运动模型目标跟踪方法

 机载预警雷达存在不可忽略的多普勒盲区问题。在目标跟踪的过程中,该盲区容易造成目标航迹中断和重起批。针对该问题,提出了一种基于多假设运动模型的目标跟踪方法。该方法根据多普勒盲区对目标状态的约束形成多个假设运动模型,当新出现的量测值落入任何一个运动模型形成的关联波门内,则航迹关联成功。仿真结果表明,该算法在不同盲区范围条件下,针对不同机动能力的目标均具有较高的航迹关联率,有效提高了目标连续跟踪性能。     

Fast music spectrum peak search VIA Metropolis-Hastings sampler

A fast MUltiple Signal Classification （MUSIC） spectrum peak search algorithm is devised, which regards the power of the MUSIC spectrum function as target distribution up to a constant of proportionality, and uses Metropolis-Hastings （MH） sampler, one of the most popular Markov Chain Monte Carlo （MCMC） techniques, to sample from it. The proposed method reduces greatly the tremendous computation and storage costs in conventional MUSIC techniques i.e., about two and four orders of magnitude in computation and storage costs under the conditions of the experiment in the paper respectively.     

一种新的贝叶斯调制分类算法

提出了一种基于马尔可夫链蒙特卡罗(MCMC)的数字调制分类方法。针对存在未知残留载波相位和频率时贝叶斯分类难以实现的问题,采用Metropolis-Hastings(M-H)算法估计边缘似然概率密度,从而在分类性能上保持了贝叶斯分类的理论最优性和稳健性。利用对比实验验证了方法的性能。     

一种无线传感器网络中目标跟踪的自适应节点调度算法

在无线传感器网络目标跟踪的过程中进行节点调度,可以综合考虑跟踪误差和能量消耗,延长传感器网络的使用寿命。为了综合考虑节点调度的短期和长远损失,该文将问题建模为部分可观测马尔科夫决策过程(POMDP)以得到更优的调度策略,并提出一种近似求解算法C-QMDP。该算法利用马尔科夫链蒙特卡洛方法(MCMC)推导连续状态空间的置信状态的转移,并计算瞬时代价。使用状态离散化方法,基于马尔科夫决策过程(MDP)值迭代求解未来代价的近似值。仿真结果表明,相比现有POMDP近似算法,该文算法既可以降低跟踪过程中的累积损失,又可以将大量运算进行离线计算,减小了在线决策时的计算量。     

A probabilistic solution to the MEG inverse problem via MCMC methods: the reversible jump and parallel tempering algorithms

We investigated the usefulness of probabilistic Markov chain Monte Carlo (MCMC) methods for solving the magnetoencephalography (MEG) inverse problem, by using an algorithm composed of the combination of two MCMC samplers: Reversible Jump (RJ) and Parallel Tempering (PT). The MEG inverse problem was formulated in a probabilistic Bayesian approach, and we describe how the RJ and PT algorithms are fitted to our application. This approach offers better resolution of the MEG inverse problem even when the number of source dipoles is unknown (RJ), and significant reduction of the probability of erroneous convergence to local modes (PT). First estimates of the accuracy and resolution of our composite algorithm are given from results of simulation studies obtained with an unknown number of sources, and with white and neuromagnetic noise. In contrast to other approaches, MCMC methods do not just give an estimation of a "single best" solution, but they provide confidence interval for the source localization, probability distribution for the number of fitted dipoles, and estimation of other almost equally likely solutions.     

A new likelihood-based modulation classification algorithm using MCMC

In this paper, a new likelihood-based method for classifying phase-amplitude-modulated signals in Additive White Gaussian Noise (AWGN) is proposed. The method introduces a new Markov Chain Monte Carlo (MCMC) algorithm, called the Adaptive Metropolis (AM) algorithm, to directly generate the samples of the target posterior distribution and implement the multidimensional integrals of likelihood function. Modulation classification is achieved along with joint estimation of unknown parameters by running an ergodic Markov Chain. Simulation results show that the proposed method has the advantages of high accuracy and robustness to phase and frequency offset.     

An improved Markov Chain Monte Carlo method for MIMO iterative detection and decoding

Recently, a new soft-in soft-out detection algorithm based on the Markov Chain Monte Carlo （MCMC） simulation technique for Multiple-Input Multiple-Output （MIMO） systems is proposed, which is shown to perform significantly better than their sphere decoding counterparts with relatively low complexity. However, the MCMC simulator is likely to get trapped in a fixed state when the channel SNR is high, thus lots of repetitive samples are observed and the accuracy of A Posteriori Probability （APP） estimation deteriorates. To solve this problem, an improved version of MCMC simulator, named forced-dispersed MCMC algorithm is proposed. Based on the a posteriori variance of each bit, the Gibbs sampler is monitored. Once the trapped state is detected, the sample is dispersed intentionally according to the a posteriori variance. Extensive simulation shows that, compared with the existing solution, the proposed algorithm enables the markov chain to travel more states, which ensures a near-optimal performance.     

Multitarget state and track estimation for the probability hypotheses density filter

The particle Probability Hypotheses Density (particle-PHD) filter is a tractable approach for Random Finite Set (RFS) Bayes estimation, but the particle-PHD filter can not directly derive the target track. Most existing approaches combine the data association step to solve this problem. This paper proposes an algorithm which does not need the association step. Our basic ideal is based on the clustering algorithm of Finite Mixture Models (FMM). The intensity distribution is first derived by the particle-PHD filter, and then the clustering algorithm is applied to estimate the multitarget states and tracks jointly. The clustering process includes two steps: the prediction and update. The key to the proposed algorithm is to use the prediction as the initial points and the convergent points as the estimates. Besides, Expectation-Maximization (EM) and Markov Chain Monte Carlo (MCMC) approaches are used for the FMM parameter estimation.     

MCMC粒子滤波算法研究及应用

粒子滤波算法是一种基于贝叶斯估计的蒙特卡罗方法,适用于非线性非高斯系统的分析,被广泛应用于跟踪、定位等问题的研究中。为了解决粒子滤波算法在重采样后,丧失粒子多样性的问题,本文在粒子滤波算法的重采样步骤后,加入了马尔可夫链蒙特卡罗（Markov Chain Monte Carlo,简称MCMC）移动步骤,增加粒子的多样性。利用粒子滤波算法和MCMC粒子滤波算法对目标跟踪问题进行了仿真,并且通过分析仿真实验结果,比较了两种算法的性能,结果说明加入MCMC粒子滤波算法的性能优于粒子滤波算法。     

Classification of chirp signals using hierarchical Bayesianlearning and MCMC methods

This paper addresses the problem of classifying chirp signals using hierarchical Bayesian learning together with Markov chain Monte Carlo (MCMC) methods. Bayesian learning consists of estimating the distribution of the observed data conditional on each class from a set of training samples. Unfortunately, this estimation requires to evaluate intractable multidimensional integrals. This paper studies an original implementation of hierarchical Bayesian learning that estimates the class conditional probability densities using MCMC methods. The performance of this implementation is first studied via an academic example for which the class conditional densities are known. The problem of classifying chirp signals is then addressed by using a similar hierarchical Bayesian learning implementation based on a Metropolis-within-Gibbs algorithm