Kalman Filter for Generalized 2-D Roesser Models

The design problem of the state filter for the generalized stochastic 2-D Rocsser models, which appears when both the state and measurement are simultaneously subjected to the interference from white noise, is discussed. The wellknown Kalman filter design is extended to the generalized 2-D Roesser models. Based on the method of ＂scanning line by line＂, the filtering problem of generalized 2-D Roesser models with mode-energy reconstruction is solved. The formula of the optimal filtering, which minimizes the variance of the estimation error of the state vectors, is derived. The validity of the designed filter is verified by the calculation steps and the examples are introduced.     

Research on Simulation of Langlie Method Test of Fuze Arming Distance

In mathematically statistical test methods that were used to get arming distance of fuze, Langlie method has been widely applied because it only use a few samples. Monte-Carlo method was used to simulate and calculate Langlie method test of fuze arming distance by using computer. The result shows that the larger error and scatter exist in the esti- mate of arming distance variance although 50% response level of arming distance can be estimated using a little sample; the correction coefficient of variance estimate can be got by simulating and calculating, but it is useless to a certain single test; this means that a larger error exists when Langlie method test is used to get the muzzle safety distance and the arm- ing distance of fuze, and the maximum arming distance becomes shorter and the minimum one longer without correcting.     

Computer Vision Method in Human Motion Detection

Human motion detection based on computer vision is a frontier research topic and is causing an increasing attention in the field of computer vision research. The wavelet transform is used to sharpen the ambiguous edges in human motion image. The shadow＇s effect to the image processing is also removed. The edge extraction can be successfully realized. This is an effective method for the research of human motion analysis system.     

Design Method of Equipment Optimization Development Based on Standardization Theory

The matters of equipment optimization development are usually discrete, fuzzy and non-quantitative. It is difficult directly to optimize the equipment development with a mathematical model. A set of methods for designing the equipment optimization development with six di- mensions and eight main elements is established based on the theory and method of standardization. The top-tier design space of systematic development of equipment is built up by the relations of basic models, series and model spectrums. The relations of time and space for equipment optimization development are established. The design processes of a six dimension systematic space are expounded. The connotation of each plan in the main system space is analyzed. A design method for an entire equipment is established with standardization theory. The coordinating design methods of equipment technical system and the optimization design methods of equipment integration are discussed. The design methods for universalization and serialization of components and parts are established. The design methods of equipment optimization development highlight the relations of the basic model of platform, the serialization of platform basic models, the modularization of equipment functions, the model spectrum of variant equipment, and the universalization and serialization of components and parts.     

Automotive Interior Noise Reduction in High Frequency Using Statistical Energy Analysis

Statistical energy analysis （SEA） is an effective method for predicting high frequency vibro-acoustic performance of automobiles. A full vehicle SEA model is presented for interior noise reduction. It is composed of a number of subsys- tems based on a 3D model with all parameters for each subsystem. The excitation inputs are measured through road tests in different conditions, including inputs from the engine vibration and the sound pressure of the engine bay. The accuracy in high frequency of SEA model is validated, by comparing the analysis results with the testing pressure level data at driv- er＇s right ear. Noise contribution and sensitivity of key subsystems are analyzed. Finally, the effectiveness of noise reduction is verified. Based on the SEA model, an approach combining test and simulation is proposed for the noise vibra- tion and harshness （NVH） design in vehicle development. It contains building the SEA model, testing for subsystem parameter identification, validating the simulation model, identifying subsystem power inputs, analyzing the design sensi- tivity. An example is given to demonstrate the interior noise reduction in high frequency.     

Research of the Adaptive Beamformer Based on the Frequency Energy Normalization

An algorithm of broadband minimum variance distortionless response （MVDR） based on the frequency energy normalization is proposed. First, every narrowband frequency component of the broadband signal is normalized by the total narrowband energy of all array elements, and the narrowband power is calculated by MVDR. Finally, final spatial energy spectrum can be obtained by averaging or summing all results of every narrowband frequency bin. Any prior-information about the noise or the signal is unnecessary for the proposed method in this paper. The processing gain of the proposed method compared to the conventional broadband MVDR can be obtained as long as the amplitude fluctuation of the array noise frequency spectrum is severer than that of the target signal. The validity of the method is validated by the optimal signal detection theory. Simulation and real data are used to validate the performance of the method. Analysis results show that about 4 dB processing gain compared to the general broadband MVDR can be reached by the proposed method.     

Research on Instantaneous Thrust Measurement for Attitude-control Solid Rocket Motor

In order to measure the instantaneous thrust of a certain attitude-control solid rocket motor, based on the analysis of the measurement principles, the difference between the instantaneous thrust and steady thrust measurements is pointed out. According to the measurement characteristics, a dynamic digital filter compensation method is presented. Combined the identification-modeling, dynamic compensation and simulation, the system＇s dynamic mathematic model is established. And then, a compensation digital filter is also designed. Thus, the dynamic response of the system is improved and the instantaneous thrust measurement can be implemented. The measurement results for the rocket motor show that the digital filter compensation is effective in the instantaneous thrust measurement.     

An Evaluation Approach for Operational Effectiveness of Anti-radiation Weapon

With the development of anti-radiation weapons,the effectiveness evaluation of anti-radiation weapons has been turned from the simple accuracy index to the integrated countermeasure capability.The research priority is how to access the combat effectiveness of anti-radiation weapons in a complex countermeasure environment.For the present situation of range test of anti-radiation weapons,a combat effectiveness assessment model based on non-linear index aggregation is proposed for anti-radiation weapons.And the corresponding index system model,index aggregation methods,index marking method and index weight determination are given.Finally,the simulation results verify the efficiency and feasibility of the proposed method.     

A Magnetic Disturbance Compensation Method Based on Magnetic Dipole Magnetic Field Distributing Theory

The interference of carrier magnetic field to geomagnetic field has been a difficult problem for a long time, which influences on the deviation of navigation compass and the error of geomagnetic measurement. To increase the geomagnetic measuring accuracy required for the geomagnetic matching localization, the strategy to eliminate the effect of connatural and induced magnetic fields of carrier on the geomagnetic measuring accuracy is investigated. The magnetic- dipole＇s magnetic field distributing theory is used to deduce the magnetic composition in the position of the sensor installed on the carrier. A geomagnetic measurement model is established by using the measuring data with the ideal sensor. Con- sidering the magnetic disturbance of carrier and the error of sensor, a geomagnetic measuring compensation model is built. This model can be used to compensate the errors of carrier magnetic field and magnetic sensor in any case and its parame- ters have clear or specific physical meaning. The experimented results show that the model has higher geomagnetic mea- suring accuracy than that of others.     

Application of Space-time Conservation Element and Solution Element Method in Intake and Exhaust Flows of High Power Density Diesel Engine

A one-dimensional pipe flow model of single-cylinder diesel engine is established to investigate the intake and exhaust flow characteristics of diesel engine in the condition of high power density （HPD）. A space-time conservation element and solution element （CE/SE） method is used to derive the discrete equations of the partial differential equation for the intake and exhaust systems. The performance parameters of diesel engine with speed of 2100 r/min are simulated. The simulated results are in accordance with the experimental data. The effect of increased power density on charging coefficient is analyzed using a validated model. The results show that the charging coefficient is slowly improved with the increase in intake pressure, and is obviously reduced with the increase in engine speed.     

基于6 类噪声项拟合模型的光纤陀螺噪声特性分析方法

针对传统的陀螺噪声特性分析方法出现拟合模型不准确的问题,提出一种基于6 类噪声项的拟合模型及分段拟合方法。采样某型光纤陀螺数据,分析了导致拟合模型不准确的内在机理,指出在光纤陀螺随机噪声中存在低频正弦项噪声成分,该项噪声在传统的5 类噪声拟合模型中通常被忽略。对于精度较高的光纤陀螺,这种忽略处理导致其拟合模型不合理、拟合系数结果不准确。通过对实测陀螺信号进行时域、频域分析,确定正弦项噪声的频率,将正弦项噪声纳入拟合模型中,提出一种包含6 类噪声项的拟合模型,同时为减小正弦项噪声、量化噪声项、零偏不稳定项、速率斜坡项等因相关时间相近而带来的耦合误差,提出一种分段拟合方法。针对某型光纤陀螺的实测数据的Allan 方差,基于6 类噪声项的拟合模型,采用文中所提方法进行噪声特性分析。结果表明:六类噪声项的拟合模型的拟合误差很小,拟合系数准确、可信。     

基于码载偏离度的改进自适应Hatch滤波算法

针对单频地基增强系统（GBAS）中载波相位平滑伪距精度易受电离层延时和伪距测量噪声影响的问题,分析卫星信号码载偏离度对Hatch滤波器平滑精度影响,提出一种基于码载偏离度的自适应Hatch滤波算法。根据伪距和载波相位观测值计算码减载波,建立其1阶线 性模型;在此基础上采用最小二乘法估计电离层延时变化率,由此分离得到伪距测量噪声;建立平滑后伪距误差均方根与电离层延时变化率、伪距测量噪声标准差以及Hatch滤波器平滑时间三者之间的函数模型,并根据该函数表达式计算得到滤波器最优平滑时间。利用GBAS原理样机进行了验证实验,结果表明：自适应Hatch滤波算法能够根据实时计算得到的电离层延时变化率和伪距测量噪声标准差确定滤波器最优平滑时间,且在机载差分定位中采用自适应Hatch滤波算法平滑伪距后其位置精度相比传统固定平滑时间算法最大提高了53.19%,验证了所提算法的有效性。     

基于辅助模型粒子滤波的混沌信号降噪方法

针对传统的扩展卡尔曼滤波方法和无迹卡尔曼滤波方法不能有效地抑制混沌系统的加性噪声这一问题,给出了辅助模型粒子滤波算法,推导了混沌系统的状态空间描述,提出了一种基于辅助模型粒子滤波的混沌信号降噪方法,并将其用于Lorenz混沌信号的降噪。在叠加高斯噪声情况下对混沌系统进行降噪处理实验。结果表明,所提出的降噪方法对含噪Lorenz混沌信号有着较明显的降噪效果。     

基于SNVA的机动目标状态估计

利用位置预测估计值与位置滤波估计值之间的偏差进行加速度方差自适应调节,提出一种基于状态噪声方差自适应(SNVA)的机动目标状态估计方法。采用SNVA对目标加速度噪声方差进行自适应调整,实现了对当前统计模型的改进; 利用扩展卡尔曼滤波算法对目标状态进行估计。仿真结果表明,基于SNVA的扩展卡尔曼滤波算法对机动目标速度估计的绝对误差小于0.1 m/s,加速度估计的绝对误差小于0.1 m/s²,能够对机动目标的状态进行准确的估计。     

增强型比例导引系统制导性能的研究

应用随机过程及成型滤波器的理论知识,构建了目标随机机动及过程噪声模型,建立了基于过程噪声与测量噪声的增强型比例导引工程应用模型,设计了卡尔曼滤波器来估计系统状态,引入蒙特卡洛法计算脱靶量均方差.通过仿真,分析了采用过载驾驶仪的增强型比例导引系统不同的制导性能指标,并与比例导引制导律进行对比分析,结果表明,测量噪声较大时APN对噪声的抑制效果好于PN,这为增强型比例导引的工程应用提供了依据.     

改进型中值滤波在图像处理中的应用

去噪处理是图像处理中较为重要的环节,处理的好坏将直接影响后续工作;介绍了中值滤波的滤波特点,针对标准中值滤波在图像去噪和保护细节上的缺陷,提出了一种改进的中值滤波算法,通过软件仿真,结果表明：该算法在有效地去除脉冲噪声的同时,很好地保护了边缘细节,较标准中值滤波具有更优良的滤波效果。     

基于Allan方差自适应算法的姿态解算

为解决MEMS 姿态传感器的复杂噪声问题,设计使用一种基于Allan 方差的自适应算法在线估计量测噪 声方差。基于Allan 方差递推公式组成自适应算法来追踪数据的方差值,采用欧拉角微分方程作为滤波的状态方程, 通过对陀螺仪静态数据Allan 方差分析得到陀螺仪的主要噪声参数用作滤波系统噪声方差,并将各个数据整合解算 出姿态角。结果表明：自适应滤波算法比常规滤波方法解算的角度精度高,在噪声波动的环境条件下,自适应滤波 算法实用性更好。     

混合噪声条件下的目标被动定位算法

为提高被动传感器观测噪声为含时变有色噪声、跳变噪声的混合噪声时容积卡尔曼滤波（CKF）算法的滤波精度和稳定性,提出一种自适应容积卡尔曼滤波（ACKF）算法。在ACKF算法中,在基本CKF算法基础上,采用观测重构、待定系数去相关方法,推导得到有色噪声条件下的容积卡尔曼滤波算法。针对时变有色噪声和跳变噪声导致滤波精度受损的问题,引入噪声方差在线修正及有害观测剔除的思想,进行了ACKF算法设计。仿真结果表明,与基本CKF算法相比,ACKF算法在x轴、y轴、z轴3个方向得到的被动定位精度分别提升了24.75％、32.57％和28.48％,具有更高的滤波稳定性和精度。     

基于谐波小波的舰船辐射噪声线谱提取方法

针对传统方法在低信噪比情况下难以准确提取舰船辐射噪声线谱成分的问题,提出一种基于谐波小波变换的高分辨线谱提取方法。通过对舰船辐射噪声信号进行谐波小波变换,将其正交、无泄漏地分解到相互独立的频段上,提取线谱所在频段的谐波小波系数且将其它频段置零,进而在时域重构出线谱信号,实现信号与其它成分的分离。实验分析结果表明:该方法对背景噪声有较好的抑制作用,提取微弱线谱信号的能力和精度优于FFT分析方法,比传统FIR滤波器方法性能提高了约5dB,有利于辐射噪声特征线谱的提取。     

一种抗海浪扰动实时控制信号滤波方法

为了克服伺服控制系统中滤波效果与系统相位裕度不能兼顾,消除高频噪声会损失有用低频信号的问题,以卡尔曼滤波算法为基础,提出了一种抗海浪用实时控制信号滤波方法,该方法运用状态空间法描述系统,采用2阶自回归模型计算系统参数,以递推算法实现计算机实时处理,从而达到大幅降低信号高频噪声,抑制陀螺漂移,提取有用信号的目的。仿真结果表明,该滤波方法简单,实现方便,抑制性好,可有效减小系统的相位损失,消除了高频干扰,对提高系统带宽与系统开环增益有很大贡献。