High‑resolution silicon photonic sensor based on a narrowband microwave photonic flter

Microwave photonic sensors are promising for improving sensing resolution and speed of optical sensors.In this paper,a high-sensitivity,high-resolution temperature sensor based on microwave photonic flter(MPF)is proposed and demonstrated.A micro-ring resonator(MRR)based on silicon-on-insulator is used as the sensing probe to convert the wavelength shift caused by temperature change to microwave frequency variation via the MPF system.By analyzing the frequency shift with high-speed and high-resolution monitors,the temperature change can be detected.The MRR is designed with multi-mode ridge waveguides to reduce propagation loss and achieves an ultra-high Q factor of 1.01×10^(6).The proposed MPF has a single passband with a narrow bandwidth of 192 MHz.With clear peak-frequency shift,the sensitivity of the MPF-based temperature sensor is measured to be 10.22 GHz/℃.Due to higher sensitivity and ultra-narrow bandwidth of the MPF,the sensing resolution of the proposed temperature sensor is as high as 0.019℃.

A FIR flter assisted with the predictive model and ELM integrated for UWB-based quadrotor aircraft localization

To improve the accuracy of the Ultra-Wide Band(UWB)based quadrotor aircraft localization,a Finite Impulse Response(FIR)flter aided with an integration of the predictive model and Extreme Learning Machine(ELM)is proposed in this work.The FIR flter estimates the quad-rotor aircraft’s position by fusing the positions measured with the UWB and Inertial Navigation System respectively.When the UWB dada are unavailable,both the ELM and the predictive model are used to provide the measurements,replacing those unavailable UWB data,for the FIR flter.The ELM estimates the measurement via the mapping between the one step prediction of state vector and the measurement built when the UWB data are available.For the predictive model,we mathematically describe the missing UWB data.Then,both the measurements estimated with the ELM and predictive model are employed to estimate the observations via Mahalanobis distance.The test results show that the FIR flter aided by the predictive model/ELM integrated can reduce the Cumulative Distribution Function and position Root Mean Square Error efectively when the UWB is unavailable.Compared with the ELM assisted FIR flter,the proposed FIR flter can reduce the localization error by about 48.59%,meanwhile,the integrated method is close to the method with a better solution.

Multiple model particle flter track-before-detect for range ambiguous radar

The middle pulse repetition frequency（MPRF）and high pulse repetition frequency（HPRF）modes are widely adopted in airborne pulse Doppler（PD）radar systems,which results in the problem that the range measurement of targets is ambiguous.The existing data processing based range ambiguity resolving methods work well on the condition that the signal-to-noise ratio（SNR）is high enough.In this paper,a multiple model particle flter（MMPF）based track-beforedetect（TBD）method is proposed to address the problem of target detection and tracking with range ambiguous radar in low-SNR environment.By introducing a discrete variable that denotes whether a target is present or not and the discrete pulse interval number（PIN）as components of the target state vector,and modeling the incremental variable of the PIN as a three-state Markov chain,the proposed algorithm converts the problem of range ambiguity resolving into a hybrid state fltering problem.At last,the hybrid fltering problem is implemented by a MMPF-based TBD method in the Bayesian framework.Simulation results demonstrate that the proposed Bayesian approach can estimate target state as well as the PIN simultaneously,and succeeds in detecting and tracking weak targets with the range ambiguous radar.Simulation results also show that the performance of the proposed method is superior to that of the multiple hypothesis（MH）method in low-SNR environment.

An indoor fusion navigation algorithm using HV-derivative dynamic time warping and the chicken particle flter

The use of dead reckoning and fngerprint matching for navigation is a widespread technical method.However,fngerprint mismatching and low fusion accuracy are prevalent issues in indoor navigation systems.This work presents an improved dynamic time warping and a chicken particle flter to handle these two challenges.To generate the Horizontal and Vertical(HV)fngerprint,the pitch and roll are employed instead of the original fngerprint intensity to extract the horizontal and vertical components of the magnetic feld fngerprint.Derivative dynamic time warping employs the HV fngerprint in its derivative form,which receives higher-level features because of the consideration of fngerprint shape information.Chicken Swarm Optimization(CSO)is used to enhance particle weights,which minimizes position error to tackle the particle impoverishment problem for a fusion navigation system.The results of the experiments suggest that the enhanced algorithm can improve indoor navigation accuracy signifcantly.

Bernoulli particle flter with observer altitude for maritime radiation source tracking in the presence of measurement uncertainty

For maritime radiation source target tracking in particular electronic counter measures（ECM）environment,there exists two main problems which can deteriorate the tracking performance of traditional approaches.The frst problem is the poor observability of the radiation source.The second one is the measurement uncertainty which includes the uncertainty of the target appearing/disappearing and the detection uncertainty（false and missed detections）.A novel approach is proposed in this paper for tracking maritime radiation source in the presence of measurement uncertainty.To solve the poor observability of maritime radiation source target,using the radiation source motion restriction,the observer altitude information is incorporated into the bearings-only tracking（BOT）method to obtain the unique target localization.Then the two uncertainties in the ECM environment are modeled by the random fnite set（RFS）theory and the Bernoulli fltering method with the observer altitude is adopted to solve the tracking problem of maritime radiation source in such context.Simulation experiments verify the validity of the proposed approach for tracking maritime radiation source,and also demonstrate the superiority of the method compared with the traditional integrated probabilistic data association（IPDA）method.The tracking performance under different conditions,particularly those involving different duration of radiation source opening and switching-off,indicates that the method to solve our problem is robust and effective.

A second-order numerical method for elliptic equations with singular sources using local flter

The presence of Dirac delta function in differential equation can lead to a discontinuity,which may degrade the accuracy of related numerical methods.To improve the accuracy,a secondorder numerical method for elliptic equations with singular sources is introduced by employing a local kernel flter.In this method,the discontinuous equation is convoluted with the kernel function to obtain a more regular one.Then the original equation is replaced by this fltered equation around the singular points,to obtain discrete numerical form.The unchanged equations at the other points are discretized by using a central difference scheme.1D and 2D examples are carried out to validate the correctness and accuracy of the present method.The results show that a second-order of accuracy can be obtained in the fltering framework with an appropriate integration rule.Furthermore,the present method does not need any jump condition,and also has extremely simple form that can be easily extended to high dimensional cases and complex geometry.

压滤机传动系统动态特性分析及结构参数优化

为解决压滤机在实际生产过程中由于其传动系统结构参数不合理导致设备出现抖振和噪声的问题,在基于Simulink软件对压滤机传动系统动态特性仿真分析的基础上,通过正交试验设计的方式对压滤机传动系统中压榨辊的相对位置及直径等结构参数进行优化,并对优化前后压滤机传动系统的张力波动幅值进行对比,对优化效果进行评估。

不同身体姿势对雷达式生命体征监测系统的影响

目的研究在生物雷达监护系统中,不同的身体姿势对雷达回波信号提取生命体征参数的影响。方法设计实验采用监护过程中最常见的平躺和坐姿两种姿势,研究上述姿势的生物雷达回波信号分析方法,提出改进自适应对消滤波算法。结果两种姿势下,自适应抵消器输出滤波信号的中心频率与同步监测的心跳信号频率一致,且位于该点的信号能量最强。结论运用改进的自适应对消滤波算法能够在不同的姿势状态下,得到有效的生命体征参数呼吸和心跳信号。

多孔不锈钢管与致密法兰焊接工艺

通过研究过滤管与法兰间的联接形式、焊接参数对焊缝热影响区、熔深和外观质量的影响,提出了获得较小热影响区且全焊透焊缝的理想工艺。

一种用于JPEG2000的小波变换VLSI结构设计方法

为了快速地进行小波变换,提出了一种应用于JPEG2000的基于提升格式5/3,9/7统一的离散小波滤波单元;同时对于行列并行滤波,提出了一种控制机制,其在缓存5行的条件下,可完成高速行列并行滤波操作。该方法在保证精度条件下,可以取得较高的硬件利用率,且中间数据暂存空间需求低。然后在提升结构基础上,完成了硬件模块设计,并进行了仿真和FPGA实现。最后用Verilog HDL对系统进行了硬件描述,并在Altera DE2的验证板上的cyclone2 EP2C35FC672芯片上,在Quartus 6.0环境下实现了该结构功能。

采用压力传感器同时测量动态压力与温度

本文阐述利用硅压阻式压力传感器在测压同时输出测温信号的原理与方法.在恒流供电条件下,对YZW-84型φ2.8mm 微型压力传感器进行了静态温度标定;在微机数据采集系统上测定了阶跃温度响应特性,借助软件进行数字滤波后,使YZW 型压力传感器的测温动态范围扩展1～2个数量级.

袋式除尘器用滤料失效分析

随着袋除尘在工业烟尘控制领域的广泛应用,滤料失效越来越引起行业重视。应用故障树分析方法系统研究了滤料失效的模式,并对滤料破损失效、滤料阻力增大失效、滤料透滤排放超标失效进行了致因分解,找出了引起滤料失效的最基本原因事件,对指导现场安全使用滤料有较好的帮助。

配电系统电能质量调节器的研究

分析了统一电能质量调节器的基本结构及工作原理,根据其串、并联部分的不同特点,采用不同的检测控制策略。仿真结果表明,统一电能质量调节器不但可以补偿非线性负载产生的无功电流和谐波电流,还能对电源电压的畸变量进行动态补偿。

测井信号的可逆性及其实现

当测井信号为褶积系统的输出或者可用具有可逆性的自回归滑动平均模型模拟时，测井信号可逆．导出了二个测井信号恢复岩石真值的引理及方法，一是反褶积；二是用ＡＲＭＡ模型的逆函数．提出了同态滤波、维纳滤波、自然伽马测井反褶积中的形状系数等结合测井实际的具体方法，并通过实例表示了上述方法的可行性和效果．

微带SIR电容间隙耦合带通滤波器的设计

本文提出了一种新的基于SIR谐振器的微带电容间隙耦合(Capacitive-Gap-Coupled,CGC)带通滤波器结构。首先根据滤波器的低通原型设计、计算了滤波器的参数,并使用微波CAD软件对设计的尺寸进行了优化、仿真。仿真结果表明该类型滤波器的频带响应具有优良的频带响应,二阶谐波通带的中心频率和理论计算一致,通过调整SIR谐振器的阻抗比可以控制二阶谐波中心频率的位置。

光伏发电系统并网逆变器研究综述

阐述了当前光伏发电系统并网逆变器的研究现状。介绍了目前逆变器常见的拓扑结构及其各自的特点与适用类型。以滤波性能和生产成本为衡量指标,分析了不同滤波器的优缺点。针对光伏阵列的最大功率点跟踪技术,提出最近几年国内外学者对扰动观察法和电导增量法的多种改进,并重点论述了光伏并网逆变器的并网电流控制策略,说明了逆变器的控制目标与当下的控制思想。

钢铁行业烟尘的无组织排放与控制

介绍了无组织排放的定义和特征,阐述了无组织排放控制基本思想,分析了钢铁企业常见的料场扬尘、物料转运扬尘、移动尘源污染、冶炼烟尘逸散等无组织排放产生原因,提出了控制方案。介绍了预荷电袋滤器和海岛纤维超细面层滤料等新技术成果及其工业应用,可为钢铁行业实现烟尘细颗粒物超低排放提供技术和装备支持,为企业环保提标改造提供工程案例。

一种快速精确的捷联惯导系统初始对准方法研究

传统的多位置对准方法虽然使捷联惯导系统静基座初始对准的精度得到提高,但是用卡尔曼滤波器对其状态变量进行估计时,方位失准角收敛很慢。本文提出了一种快速多位置对准估计方位失准角的方法,直接利用两水平失准角快速收敛的估计结果对传统多位置对准中方位失准角的估计,从而大大提高了捷联惯导系统静基座对准的精度和速度,计算机仿真结果验证了该方法的有效性。

自适应滤波在激光雷达中的应用

针对存在斑纹和湍流这两类乘性噪声的激光雷达系统,讨论了对数回波功率的估计问题。在模型参数未知的情况下,在自适应滤波中采用分割法,并给出了自适应滤波方程。仿真结果表明,在同时存在斑纹和湍流噪声的情况下,本文给出的自适应滤波算法优于只考虑斑纹噪声的滤波算法。

电荷放大器滤波设置对加速度计相移测量结果影响的仿真与验证

为了分析电荷放大器滤波设置对加速度计相移测量结果的影响,采用LabVIEW图形化编程语言,仿真计算正弦信号通过不同二阶高通、低通滤波器后的相移偏差测量结果。用激光绝对法振动标准装置测量振动标准套组在不同高通、低通滤波器的相移偏差实验。通过对比实际测量数据和仿真结果,得到结论:在相移测量中,加速度传感器配套使用的电荷放大器高通、低通滤波器截止频率,应根据测量系统的动态特性和实际振动输入信号波形的具体形状和变化趋势来合理选择,以满足振动加速度测量不确定度的要求。电荷放大器的滤波频率,必须在测量结果中说明实际测量时的相应设置。