连续纯方位系統的可观测性分析

证明了连续纯方位观测系统可观测的一个充分必要条件是存在4个方位构成的可观测判别式不等于0，其特点是仅利用方位信息而无需导数信息和求解微分方程。分析了系统不可观测时观测器的运动形态，指出纯方位系统不可观测时，观测器的运动轨迹是一种等效的匀速直线运动观测轨迹。应用这些结论得到了约束假定条件下目标机动的一个判断准则。     

只测角的单站三维红外被动测距算法

研究只测角的单站三维被动测距算法。在三维空间运动几何模型的基础上，通过适当选择观测平台所在的地面坐标系，建立了目标距离变化与观测器位移的关系方程。同时，对高速运动物体的轨迹采用分段线性拟合的策略，即在较小采样间隔的情况下，假定连续三个观测时刻上的目标或观测器各自处于直线运动状态，即三点共线。该关系方程结合三点共线的假设，即可求解出目标到观测器的距离。缩比模型试验表明，该算法简便可行，测距相对误差优予±10%．     

基于转换瑞利滤波器的红外目标跟踪算法

利用转换瑞利滤波器(SRF),研究了仅有角度量测的单站红外目标跟踪问题,推导了基于SRF的红外目标跟踪算法,并给出了具体步骤.该算法利用量测方程本身的非线性结构,仅在每次迭代时用"匹配"的正态分布近似代替方位量测的条件概率分布,减小了引入误差.仿真实验表明在红外目标跟踪领域,与以往EKF类的方法相比,该算法实现简单、计算量小、鲁棒性好且滤波精度较高,具有良好的实际应用价值.     

基于模糊交互多模型的机动目标被动跟踪算法

针对双观测平台纯方位测量的机动目标,提出了自适应归一化的模糊交互多模型算法。算法利用目标的方位信息,通过模糊推理机制自动调整过程噪声水平。提出了限定记忆归一化方法来自适应归一化模糊系统的输入变量,使得输入变量值始终保持在一个合理的范围内。仿真结果表明,与基于增长记忆归一化方法和经验法的模糊交互多模型算法相比,基于限定记忆归一化的模糊交互多模型算法的跟踪误差分别降低了9.56%和9.29%,能更好地跟踪机动目标的位置、速度和加速度。     

基于修正输入估计的机动目标无源跟踪

文中将修正的输入估计算法和伪线性滤波算法相结合,提出了一种对机动目标进行自适应纯方位跟踪的新算法,该算法将未知的输入向量作为新的元素补充到原来的目标状态向量中得到新的扩维状态向量,然后在只有角度测量数据的情况下利用伪线性滤波算法对原来的目标状态向量和新增的目标加速度向量同时进行估计。仿真结果表明,该算法可适应目标机动和非机动两种工作模式,能够实现对机动目标的自适应纯方位跟踪。     

几种非线性滤波只测角跟踪性能评估

为综合分析非线性滤波在只测角跟踪应用中的性能,文中给出了二维空间动态系统估计的克拉美罗界递推形式,对扩展Kalman滤波(EKF)、转换瑞利滤波(SRF)、无迹Kalman滤波(UKF)、容积Kalman滤波(CKF)和粒子滤波(PF)进行了实验仿真研究。结果表明CKF和PF可以获得高于其他滤波的精度,CKF的运算量又远低于PF,CKF可以获得精度和时效性的有效折衷。     

新型粒子滤波理论用于水下系统目标跟踪

首先介绍了粒子滤波的基本理论和状态分离技术,并将两者结合起来得到一种新的粒子滤波改进算法:PF-SP-PEKF算法.该算法提供了一种全新的寻找提议分布途径,所得提议分布在计算量适中、便于执行的前提下,更接近目标真实分布.将新算法应用到水下系统纯方位目标运动分析领域中,联合多模型方法得到MMPF-SP算法,对水下机动目标...     

Particle filter-based aerial tracking for moving targets

This paper considers the problem of tracking a moving target with a radio transmitter using an aerial robot in an online manner. The aerial robot is equipped with a low-cost directional antenna and Software Defined Radio receiver to obtain the signal emitted by the target. The aerial robot rotates around itself and collects a predefined number of signal recordings from each direction to determine the bearing angle to the target in which the received signal strength is maximized. The measurement uncertainty is assumed to be bounded and represented by two triangular areas divided by a bisector. To localize and track the target, a particle filter-based approach is proposed. In this approach, we integrate the discrete and bounded measurement model with the particle filter in such a way that the particles' weights are updated based on a novel method which considers the measurement wedge and the particle locations with respect to this wedge along with a logistic function. We also incorporate the doubling strategy into the particle filter to determine the next measurement locations and avoid arbitrarily large number of measurements. We choose wildlife monitoring as a use case scenario in which a radio transmitter is put on the animal under consideration to allow wildlife researchers to track it. Since each animal has its own motion behavior, we consider different motion models for the target, which are used in modeling animal movements in wildlife studies. Therefore, the proposed approach is validated using a target moving with varying velocity and acceleration. We verified the tracking performance of the approach through a series of extensive simulations. We compared the proposed approach with the optimal offline strategy in terms of the empirical competitive ratio of the total distance traveled and the tracking distance. We also developed a low-cost hardware platform and software infrastructure for the proposed tracking system. Using this platform, we conducted field experiments for the stationary and moving targets.     

电子侦察系统自适应跟踪数据率算法

数据率是电子侦察系统跟踪任务管理中的一个重要参数，数据率的大小决定着跟踪精度的高低，同时也影响着系统资源消耗量，为平衡跟踪精度和资源消耗的矛盾，需要一种自适应数据率算法。因为在时域上辐射源照射侦收天线的非连续性，当前主动雷达的自适应数据率算法不适用于电子侦察系统。针对以上问题引入辐射源天线扫描周期作为约束条件，改进预测协方差门限算法应用于电子侦察系统。在改进的算法中，将辐射源天线扫描周期的整数倍作为采样间隔，通过纯角度跟踪算法得到预测协方差，当预测协方差大于设定的门限时即采样。仿真结果表明，该方法可根据设定的跟踪精度，自适应采样周期，节省系统资源。     

Target localization and multicircular circumnavigation with bearing-only measurements

This article studies the multicircular circumnavigation problem of a stationary target using bearing-only measurements. The proposed estimator-based control strategy drives the networked mobile agents to move around an unknown target along different circles with any prescribed inter-agent angular spacing. The results presented in this article are as follows: First, a new estimator is developed by introducing a linear filter into an estimation algorithm which has been widely used in the existing literature. The novelty of the proposed estimator lies in its enhanced convergence rate. Analytical results show that the exponential convergence rate of the estimator can be adjusted to be arbitrarily high by increasing the estimation gain. Second, a distributed controller is designed such that global exponential convergence of the agents to the desired circular formation can be achieved. Besides, the proposed algorithms guarantee that each agent can keep a safe distance from the target, and high angular velocities of the agents can be avoided even if the circumnavigation radii become small. Finally, several numerical simulations are given to corroborate the theoretical results.