双站基于角度和时差的近似无偏定位算法

联合角度（DOA）和时差（TDOA）信息对运动目标进行无源定位实质上是一种非线性估计问题。针对将非线性观测方程转化为伪线性方程会产生有偏估计的缺点,该文基于双站定位中获得的角度和时差信息,给出了一种对三维空间目标定位跟踪的近似无偏估计滤波算法,它只需要对一对矩阵束进行广义特征分解,即可获得目标坐标和速度的估计值。计算机仿真结果表明,相比有偏估计滤波算法,如伪线性卡尔曼滤波（PLKF）算法或者最小二乘（LS）算法,该算法具有更高的定位精度,并且当观测误差增大时,其优势更加明显。     

外辐射源定位中的修正增益扩展卡尔曼滤波

针对基于外辐射源的固定单站无源定位问题,给出了一种对运动目标进行定位跟踪的改进型滤波算法。文中首先建立目标角度信息、直达波与散射波的时间差信息以及多普勒频移信息的观测方程,并推导了每个观测方程的修正增益函数,然后利用多个时刻的观测值扩充了观测方程,从而给出了一种基于扩充观测方程的修正增益扩展卡尔曼滤波（MGEKF）算法。经过计算机仿真验证,该算法可以提高定位精度,并能有效地抑制滤波发散。     

两站基于角度和时差信息的伪线性卡尔曼滤波算法及其改进

建立了两站基于角度(DOA)和时差(TDOA)信息的伪线性观测模型,基于该模型提出了匀速运动目标的伪线性卡尔曼滤波(PLKF)算法。仿真结果表明该算法的稳健性要高于扩展卡尔曼滤波(EKF)算法,当观测误差较小时,PLKF算法的定位精度要高于EKF算法;当观测误差较大时,其定位精度低于EKF算法。对此文中结合两种算法的优点,提出了改进算法,以同时提高算法的定位精度和稳健性。     

固定单站对三维运动辐射源无源定位算法及可观测性分析

实现固定单站对运动辐射源无源定位,传统的方法是测量TOA和DOA。本文将方位角变化率测量信息也引入该定位问题,提出了基于MGEKF(修正增益扩展卡尔曼滤波),对三维运动辐射源的无源定位跟踪算法。通过推导伪线性测量方程,本文进行了测量TOA和DOA对三维运动目标无源定位的可观测性分析。最后给出了计算机仿真结果。     

单站无源定位原理浅析

探讨了一种基于目标频域和空域参数测量信息，利用固定单站对机动目标进行无源定位与跟踪的算法，并详细分析了定位原理。在建立目标机动模型与测量方程的基础上，运用修正增益的扩展卡尔曼滤波（MGEKF）算法，实现对机动目标进行定位与跟踪。     

误差校正下外辐射雷达无源定位算法

针对多基外辐射源雷达定位中存在系统误差的问题,提出了一种基于到达角度(DOA)与到达时差(TDOA)的外辐射源雷达无源定位和系统误差校正算法。首先,该方法引入辅助变量对非线性的DOA 和TDOA 量测方程进行线性化,利用迭代加权最小二乘算法得到对目标位置和系统误差的联合估计;然后,利用辅助变量与目标位置的关联性,设计了一种关联最小二乘算法对初始估计值进行改进;最后,通过后验迭代估计进一步提高目标定位精度。仿真结果表明该算法能够有效地估计系统误差和目标状态。     

基于约束总体最小二乘的单站DOA/TDOA联合误差校正与定位算法

多基外辐射源雷达定位系统受系统偏差影响较大。该文针对多基外辐射源雷达到达角度(DOA)和到达时差(TDOA)联合定位系统,提出一种基于约束总体最小二乘(CTLS)的无源定位和误差校正算法。首先引入辅助变量,将DOA和TDOA非线性观测方程进行线性化处理。考虑伪线性化后定位方程中噪声矩阵各分量统计相关特性,将无源定位与误差校正联合优化问题建立为CTLS模型,并采用牛顿迭代方法对模型求解。在此基础上,考虑辅助变量与目标位置的关联性,设计关联最小二乘算法改进目标位置估计值,采用后验迭代方法进一步提高系统偏差估计精度。最后推导了算法的理论误差。仿真结果表明:该算法能够有效地估计目标位置和系统偏差。     

基于到达时间和方位角的固定单站无源定位仿真分析

基于辐射源的信号到达时间(TOA)和到达方向(DOA)信息,利用修正增益扩展卡尔曼滤波方法,对固定单站侦察设备的空中和海上目标进行无源定位,仿真计算验证算法的有效性.     

基于外辐射源的机动目标单站无源定位IMM算法

探讨一种基于外辐射源的信号到达时间差（TDOA）和信号到达方向（DOA）信息，利用固定单站对机动目标进行无源定位与跟踪的新方法。在建立目标机动模型与量测方程的基础上，运用交互式多模型（IMM）算法，实现对机动目标进行定位与跟踪。通过计算机仿真，验证了该方法的正确性与有效性。     

光电雷达对目标参数被动测量的方法研究

根据光电雷达测量到的目标方位信息，运用自适应修正增益扩展卡尔曼滤波理论。可以估计出空中目标相对载机的位置和速度参数。文章首先推导了坐标系的转换矩阵，建立数学模型后推导对应的自适应修正增益扩展卡尔曼滤波方程，通过对所得的算法进行仿真验证，表明该算法具有较好的实用性，能够满足载机对目标参数被动探测的要求。     

Target Localization Based on Angle of Arrivals

Mobile location using angle of arrival （AOA） measurements has received considerable attention. This paper presents an approximation of maximum likelihood estimator （MLE） for localizing a source based on AOA measurements. By introducing an intermediate variable, the nonlinear equations relating AOA estimates can be transformed into a set of equations which are linear in the unknown parameters. It is an approximate realization of the MLE. Simulations show that the proposed algorithm outperforms the previous contribution.     

批到达环形网络的性能分析与评价

本文提出了批到达环形网络性能分析与评价的方法，建立了平均等待时延、条件循环时间一阶矩和二阶矩的表达式，并进行了数据分析和仿真试验。     

Finite Buffer Behavior with Poisson Arrivals and Random Server Interruptions

A queueing model with finite buffer size, Poisson arrival process, synchronous transmission and server interruptions is studied through a Bernoulli sequence of independent random variables. An integrated digital voice-data system with Synchronous Time-Division Multiplexing (STDM) for voice sources and Poisson arrival process for data messages is considered as an application for this model. The relationships among overflow probabilities, buffer size and expected queueing delay due to buffering for various traffic intensities are obtained. The results of this study are portrayed on graphs and may be used as guide lines for the buffer design in digital voice-data systems. Although this study arose in the design of a buffer for digital voice-data systems, the queueing model developed is quite general and may be useful for other industrial applications.     

Centralized Wireless Data Networks With User Arrivals and Departures

A dynamic-user model for centralized wireless networks is studied, where users arrive with a certain file size and depart when the file is served by a central server. Although the exact analysis of dynamic-user systems can be complicated, it is shown that an approximate analysis can be performed in a time-scale separation regime where the file size is much larger than the time scale of service process fluctuation. A first-order approximation result is derived that shows that when file sizes are large, a complicated service process can be replaced by a simple constant-rate service process. The accuracy of the approximation is further improved through a second order approximation result that incorporates the effect of service variability. Variability in the service process is shown to reduce the effective service rate, leading to a quantification of the conventional heuristic that service variability degrades system performance     

Buffer Behavior with Poisson Arrivals and Bulk Geometric Service

This correspondence considers a buffered system with Poisson arrivals andmoutput channels subjected to geometrically distributed interruptions. The generating function of the buffet occupancy is derived and is a transcendental function. An example demonstrates the results.     

The Analysis of a Statistical Multiplexer with Nonindependent Arrivals and Errors

Most stochastic models for discrete time statistical multiplexers make the assumption that 1) arrivals are governed by a Bernoulli process and that 2) transmission errors or multiplexer failures are described by an independent error process. We study a multiplexer operating in a two state Markovian environment in which each state is characterized by its own Bernoulli arrival process and independent error process. We derive the probability generating function for the queue length distribution for such a system. We also consider two special cases of this model. One referred to as the saturated arrival model corresponds to a system in which during one of the two states, the saturated state, at least one arrival occurs during each discrete time unit. The other model, the breakdown model, corresponds to a system in which during one of the two states, the breakdown state, the multiplexer is inoperative. For both models, we generalize the analysis to cases in which the durations of the saturated state and breakdown state may take on values described by arbitrary distributions. Finally, we study the effects of different arrival processes and error processes on queue length behavior.     

Buffer Behavior for Mixed Arrivals and Single Server with Random Interruptions

A queueing model with finite buffer size, mixed input traffic (Poisson and burst Poisson arrivals), synchronous transmission and server interruptions through a Bernoulli sequence of independent random variables is studied. Using average burst length, traffic intensity and input traffic mixture ratio as parameters, the relationships among buffer size, overflow probability and expected message queueing delay are obtained. An integrated digital voice-data system with synchronous time division multiplexing (STDM) for a large number of voice sources and mixed arrival process for data messages is considered as an application for this model. The results of this study are portrayed on graphs and may be used as guidelines in buffer design problems in digital voice-data systems. The queueing model developed is quite general in a sense that it covers pure Poisson and burst Poisson arrival processes and the mixture of the two as well.     

Resource Allocation in OFDMA with Time-Varying Channel and Bursty Arrivals

This paper considers the issue of delay optimal subcarrier allocation in OFDMA wireless networks when the arrivals and channels are stochastic. Our objective is to minimize the long-term average packet delay over multiple time epochs. In previous studies, we have shown that the optimal policy is complicated and unknown. However, based on the insights learned from a simple on-off channel model, we provide heuristic policies that use different degrees of channel and queue state information. More importantly, these examples show how the significance of queue vs. channel state information varies with the traffic load. This is of extreme practical interest when one considers the overhead associated with channel estimation and feedback.     

The BMAP/G/1 Queue with Level-Dependent Arrivals – An Overview

The BMAP/G/1 queue is a field of intensive research since several years. We generalize the BMAP/G/1 queue by allowing the arrival process to depend on the state (level) of the queue, i.e., on the number of customers in the system. This will be called a BMAP/G/1 queueing system with level-dependent arrivals. A suitable arrival process is defined by nesting a countable number of BMAPs.We give conditions for the level-dependent BMAP/G/1 queue to be stable, i.e., in equilibrium. By analysing the fundamental periods, which now depend on their starting level, we determine the stationary queue length at service completion times and at an arbitrary time.