Cubature Kalman filter with closed-loop covariance feedback control for integrated INS/GNSS navigation

Cubature Kalman Filter(CKF)offers a promising solution to handle the data fusion of integrated nonlinear INS/GNSS(Inertial Navigation System/Global Navigation Satellite System)navigation.However,its accuracy is degraded by inaccurate kinematic noise statistics which originate from disturbances of system dynamics.This paper develops a method of closed-loop feedback covariance control to address the above problem of CKF.In this method,the posterior state and its covariance are fed back to the filtering process to constitute a closed-loop structure for CKF covariance propagation.Subsequently,based on the maximum likelihood principle,a control scheme of the prior state covariance is established by using the feedback state and covariance within an estimation window and further adopting a proportional coefficient to amplify the feedback terms in recent time steps for the full use of new information to reflect actual system characteristics.Since it does not directly use kinematic noise covariance,the proposed method can effectively avoid the adverse impact of inaccurate kinematic noise statistics on filtering solutions.Further,it can also guarantee the prior state covariance to be positive semi-definite without involving extra measures.The efficacy of the proposed method is validated by simulations and experiments for integrated INS/GNSS navigation.

纸基和类纸基柔性薄膜器件研究进展

近年来,柔性薄膜器件得到了蓬勃的发展,尤其是纸基或类纸基的器件由于具有低成本、柔性、多孔性、自发的液体驱动性等独特的优势,在生物、化学、物理、材料等领域都已得到了广泛的应用.得益于纸基和类纸基(柔性基质材料和光子晶体纸)等膜材料的快速发展,许多多功能、高集成的膜基器件得以问世,使得传统纸张与其他薄膜材料之间的严格界限也逐渐变得模糊.传统纸张可以被认为是一种柔性的薄膜材料,而具有适当柔性或多孔结构的薄膜材料也可以被定义为"纸".纸基和类纸基材料可以驱动液体和调控电子,制作出来的柔性薄膜器件可以用于生化分析器件和复杂的微电子器件.本文较为全面地对传统纸张以及其他柔性薄膜材料所制作的柔性薄膜器件的历史发展和最新进展进行了总结,包括纸基和类纸基柔性膜的制备方法、对微流体和电子的操控和基于这些操控所衍生出来的多元化应用.

Mahalanobis distance-based fading cubature Kalman filter with augmented mechanism for hypersonic vehicle INS/CNS autonomous integration

Inertial Navigation System/Celestial Navigation System(INS/CNS)integration,especially for the tightly-coupled mode,provides a promising autonomous tactics for Hypersonic Vehicle(HV)in military demands.However,INS/CNS integration is a challenging research task due to its special characteristics such as strong nonlinearity,non-additive noise and dynamic complexity.This paper presents a novel nonlinear filtering method for INS/CNS integration by adopting the emerging Cubature Kalman Filter(CKF)to handle the strong INS error model nonlinearity caused by HV's high dynamics.It combines the state-augmentation technique into the nonlinear CKF to decrease the negative effect of non-additive noise in inertial measurements.Subsequently,a technique for the detection of dynamic model uncertainty is developed,and the augmented CKF is modified with fading memory to tackle dynamic model uncertainty by rigorously deriving the fading factor via the theory of Mahalanobis distance without artificial empiricism.Simulation results and comparison analysis prove that the proposed method can effectively curb the adverse impacts of non-additive noise and dynamic model uncertainty for inertial measurements,leading to improved performance for HV navigation with tightly-coupled INS/CNS integration.

Hexnut[12]arene and its derivatives: Synthesis, host-guest properties, and application as nonporous adaptive crystals

Hexnut[12]arene(HN[12])and its derivatives,a new class of sixfold macrocyclic arenes,were designed and synthesized in reasonable yield by a one-pot reaction at room temperature using dimethoxymethane as a methylene source.HN[12],which bears a large,symmetric,and rigid cavity,was easily functionalized at both the methylene bridges and the hydroquinone units.A water-soluble fluorescent HN[12]was synthesized and used as a host to encapsulate benzyl viologen dichloride in water with a high binding affinity of(3.4±0.2)×10^(6)M^(-1).The nonporous adaptive crystal(NAC)of HN[12]was found to capture not only inorganic molecules(iodine)but also trace amounts of large organic molecules(basic fuchsine)from water,which greatly expands the scope of NACs for adsorption.

仿生人造生物体:次世代的人体芯片

As a magical creature,chameleon is good at adjusting body color according to the change of environment,which is good for capturing prey or protecting itself from danger.Research has shown that chameleon can adjust the nanocrystals on the surface of the skin to change the refraction of light,thus showing different colors[1].

Development of smart wearable sensors for life healthcare

Wearable biosensors are gaining tremendous interest in the clinical and biological medical fields for their potential in providing patients with real-time diagnostic tools and time-sensitive information,non-invasive measurements of biochemical markers distributed in body fluids throughout the body.These sensors replace part of the equipment that can only be installed in hospitals and become a new choice for assessing human health.Herein,critical perspectives are put forward regarding wearable sensors in the future digital health monitoring industry.Moreover,the materials and processing technologies involved have also been discussed in recent years,along with their monitoring schemes and system-level integration technologies.Finally,the probability of wearable sensors being used in early disease detection is considerable.Thus,despite potential challenges,it is still quite promising for wearable sensors to come into production.

Emerging electrochemical sensors for life healthcare

As electrochemical sensors possess unique potential properties that are strongly related to their high sensitiv-ity,selectivity and cycling stability,making it extensively used in versatile fields of biosensing,electrochemical analysis and drug delivery.Notably,recent evidence demonstrates that electrochemical technology provides a promising platform for life healthcare by biocompatibility of mimicking human tissue to report electrical signals,potentially enabling timely disorder prediction through non-invasive real time and simultaneous health monitoring.This review focuses on the comprehensive set of advances in the field of electrochemical devices for life healthcare,including fabrication,analytical performance,and their multiple applications in clinical settings are deliberated.