The Design of I/O Subsystem in Satellite Real-Time Microkernel Operating System

One of the most important features of modern minor satellites is to realize autonomous moving. The performance of the satellite autonomous computer operating system acting as the control center is utmost important. The recent trend in operating system development is adopting microkernel architecture which holds such advantages as microminiaturization, modularity, portability and extendibility. The performance of I/O subsystem is currently receiving considerable research attention. Object-orientation offers an approach to application development in which software system can be constructed by composing and refining the pre-designed plug-compatible software components.It also starts with some basic notions fairly well accepted in computer science, namely encapsulation and reuse. In this paper, a new object-oriented real-time I/O subsystem model has been designed.In this model, the traditional I/O subsystem framework is discarded and a stream mechanism based on the object-oriented concept is introduced. In addition, the I/O requests are classified according to their time emergency to obtain real-time performance. So, this model meets such satelliteperformance requirements as reliability, flexibility, portability and real-time performance.

Disintegration of uncertainties associated with real-time multi-satellite precipitation products in diverse topographic and climatic area in Pakistan

Satellite-based Precipitation Estimates(SPEs)have gained importance due to enhanced spatial and temporal resolution,particularly in Indus basin,where raingauge network has fewer observation stations and drainage area is laying in many countries.Formulation of SPEs is based on indirect mechanism,therefore,assessment and correction of associated uncertainties is required.In the present study,disintegration of uncertainties associated with four prominent real time SPEs,IMERG,TMPA,CMORPH and PERSIANN has been conducted at grid level,regional scale,and summarized in terms of regions as well as whole study area basis.The bias has been disintegrated into hit,missed,false biases,and Root Mean Square Error(RMSE)into systematic and random errors.A comparison among gauge-and satellite-based precipitation estimates at annual scale,showed promising result,encouraging use of real time SPEs in the study area.On grid basis,at daily scale,from box plots,the median values of total bias(-0.5 to 0.5 mm)of the used SPEs were also encouraging although some under/over estimations were noted in terms of hit bias(-0.15 to 0.05 mm/day).Relatively higher values of missed(0.3 to 0.5 mm/day)and false(0.5 to 0.7 mm/day)biases were observed.The detected average daily RMSE,systematic errors,and random errors were also comparatively higher.Regional-scale spatial distribution of uncertainties revealed lower values of uncertainties in plain areas,depicting the better performance of satellite-based products in these areas.However,in areas of high altitude(>4000 m),due to complex topography and climatic conditions(orographic precipitation and glaciated peaks)higher values of biases and errors were observed.Topographic barriers and point scale gauge data could also be a cause of poor performance of SPEs in these areas,where precipitation is more on ridges and less in valleys where gauge stations are usually located.Precipitation system’s size and intensity can also be a reason of higher biases,because Microwave Imager underestimate precipitation in small systems(<200 km^(2))and overestimate in large systems(>2000 km^(2)).At present,use of bias correction techniques at daily time scale is compulsory to utilize real time SPEs in estimation of floods in the study area.Inter comparison of satellite products indicated that IMERG gave better results than the others with the lowest values of systematic errors,missed and false biases.

IPC Mechanisms in Satellite Real-Time Microkernel Operating System

One of the most important features of modem minor satellites is to realize autonomous moving. The perfomance of the satellite autonomous computer operating system acting as the control center is of utrnost importance. The recent trend in operating system development is adopting microkernel architecture that holds such advantages as microminiaturization, modularity, portability and extendibility. IPC is the key of microkernel design. Message-based IPC mechanism is generally used in existing microkernel Operating system. It is of consistency, safety and reliability.However, it can not provide efficient support for real-time applications in satellite systems and it only applies to loose coupling multi-processor architecture. In this paper, an improvement solution for existing message-based IPC is proposed at first to obtain real-time performance. Then a new IPC mechanism is designed. It particulary applies to shared memory tight coupling multi-processor architecture.

A New Generation of Intelligent Mapping and Remote Sensing Scientific Test Satellite Luojia-301

With the continuous improvement of the performance and the increasing variety of optical mapping and remote sensing satellites,they have become an important support for obtaining global accurate surveying and mapping remote sensing information.At present,optical mapping and remote sensing satellites already have sub-meter spatial resolution capabilities,but there is a serious lag problem in mapping and remote sensing information services.It is urgent to develop intelligent mapping and remote sensing satellites to promote the transformation and upgrading to real-time intelligent services.Firstly,based on the three imaging systems of the optical mapping and remote sensing satellites and their realization methods and application characteristics,this paper analyzes the applicable system of the intelligent mapping and remote sensing satellites.Further,according to the application requirements of real-time,intelligence,and popularization,puts forward the design concept of integrated intelligent remote sensing satellite integrating communication,navigation,and remote sensing and focuses on the service mode and integrated function composition of intelligent remote sensing satellite.Then expounds on the performance and characteristics of the Luojia-301 satellite,a new generation of intelligent surveying and mapping remote sensing scientific test satellite.And finally summarizes and prospects the development and mission of intelligent mapping remote sensing satellites.Luojia-301 satellite integrates remote sensing and communication functions.It explores an efficient and intelligent service mode of mapping and remote sensing information from data acquisition to the application terminal and provides a real service verification platform for on-orbit processing and real-time transmission of remote sensing data based on space-ground internet,which is of great significance to the construction of China’s spatial information network.

Simple real-time high-sensitivity heterodyne coherent optical transceiver at intraplane satellite communication

In this paper,we demonstrate a high-sensitivity and real-time heterodyne coherent optical transceiver for intraplane satellite communication,without digital-to-analog converter(DAC)devices and an optical phase lock loop(OPLL).Based on the scheme,a real-time sensitivity of-49 dBm is achieved at 5 Gbps QPSK.Because DAC is not needed at the transmitter,as well as OPLL at the receiver,this reduces the system cost.Furthermore,the least required Rx ADC bit-width is also discussed.Through theoretical analysis and experimental results,our cost-effective transceiver satisfies the scenario and could be a promising component for future application.

Animation simulation of satellite attitude control

Analyses the interrelation between satellite attitude and equipment failures, presents the way of animation simulation of satellite attitude control based upon the virtual reality thought, and realizes on a microcomputer the attitude control animation demonstration system for a remote sensing satellite.

A novel real-time RT-PCR with TaqM an-MGB probes and its application in detecting BVDV infections in dairy farms

A real-time RT-PCR assay using Taq Man-MGB probes was developed to detect and type the bovine viral diarrhea virus（BVDV） in cattle.Universal primers and Taq Man-MGB probes were designed from the 5′-untranslated region of known pestiviral sequences.Prior to optimizing the assay, c RNAs were transcribed in vitro from the BVDV 1 and BVDV 2 RTPCR products to make standard curves.The detection limit of the assay was 1.72×102 copies for BVDV 1 and 2.14×102copies for BVDV 2.The specificity of the assay evaluated on several BVDV strains including bovine herpesvirus 1（BHV 1）, foot and mouth disease virus（FMDV） and several classical swine fever virus（CSFV） strains showed specific detection of the positive virus over 40 cycles.The assay was highly reproducible with the coefficient of variance ranging from 1.04 to 1.33% for BVDV 1 and from 0.83 to 1.48% for BVDV 2, respectively.Using this method, we tested a total of 2 327 cattle from three dairy farms for the presence of BVDV persistently infected（PI） animals.In this assay, each RT-PCR template contained a mixture of ten samples from different animals.The occurrence rate of PI cattle in three farms ranging from 0.9 to 2.54% could represent partly the PI rates in cattle farm in China.In conclusion, using our real-time PCR assay, we could effectively detect and type BVDV and identify PI cattle in a rapid and cost-effective manner.

Application and improvement of wavelet packet de-noising in satellite transponder

The satellite transponder is a widely used module in satellite missions, and the most concerned issue is to reduce the noise of the transferred signal. Otherwise, the telemetry signal will be polluted by the noise contained in the transferred signal, and the additional power will be consumed. Therefore, a method based on wavelet packet de-noising （WPD） is introduced. Compared with other techniques, there are two features making WPD more suit- able to be applied to satellite transponders： one is the capability to deal with time-varying signals without any priori information of the input signals; the other is the capability to reduce the noise in band, even if the noise overlaps with signals in the frequency domain, which provides a great de-noising performance especially for wideband signals. Besides, an oscillation detector and an av- eraging filter are added to decrease the partial oscillation caused by the thresholding process of WPD. Simulation results show that the proposed algorithm can reduce more noises and make less distortions of the signals than other techniques. In addition, up to 12 dB additional power consumption can be reduced at -10 dB signal-to-noise ratio （SNR）.

Research on Enhancing the Functions of Animation in Web 3D

VRML offers powerful tool for generating 3D scene and realizing real time interactive animation on Web. This paper briefly introduces the related techniques of implementing interactive animation in Web 3D, focusing on how to use JavaScript to create Script node for extending VRML functions. This is very useful for virtual product design, product performance simulation, virtual assembly and remote education.

3-D Animation as Applied to the Solving of Coupling Relations in the 6-DOF Parallel Robot

How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model must first be constructed and then solved by programming.Obviously, this method is not very practical. This paper,therefore, proposes a new way of approach with a new method using 3- D animation for the solving of coupling relations in the 6 - DOF parallel robot. This method is much simpler and its solving accuracy approaches that of the more complicated analytic method.

RRVPE:A Robust and Real-Time Visual-Inertial-GNSS Pose Estimator for Aerial Robot Navigation

Self-localization and orientation estimation are the essential capabilities for mobile robot navigation.In this article,a robust and real-time visual-inertial-GNSS(Global Navigation Satellite System)tightly coupled pose estimation(RRVPE)method for aerial robot navigation is presented.The aerial robot carries a front-facing stereo camera for self-localization and an RGB-D camera to generate 3D voxel map.Ulteriorly,a GNSS receiver is used to continuously provide pseudorange,Doppler frequency shift and universal time coordinated(UTC)pulse signals to the pose estimator.The proposed system leverages the Kanade Lucas algorithm to track Shi-Tomasi features in each video frame,and the local factor graph solution process is bounded in a circumscribed container,which can immensely abandon the computational complexity in nonlinear optimization procedure.The proposed robot pose estimator can achieve camera-rate(30 Hz)performance on the aerial robot companion computer.We thoroughly experimented the RRVPE system in both simulated and practical circumstances,and the results demonstrate dramatic advantages over the state-of-the-art robot pose estimators.

Real‑time service performances of BDS‑3 and Galileo constellations with a linear satellite clock correction models

In order to facilitate high-precision and real-time Precise Point Positioning(PPP),the International GNSS(Global Navigation Satellite System)Service(IGS),BDS-3(BeiDou-3 Navigation Satellite System),and Galileo navigation satellite system(Galileo)have provided real-time satellite clock correction,which is updated at a high-frequency.However,the frequent updates pose the challenges of increasing the computational burden and compromising the timeliness of these correction parameters.To address this issue,an improved Real-Time Service(RTS)method is developed using an extrapolation algorithm and a linear model.The results indicate that a 1 h arc length of the satellite clock correction series is optimal for fitting a linear model of the RTS.With this approach,the 1 h extrapolation results for BDS-3 and Galileo are superior to 0.09 ns.Moreover,when these model coefficients are transmitted and updated at the intervals of 1,2,5,and 10 min,the corresponding PPP can converge at the centimeter-level.It is evident that these improved RTS methods outperform the current approach with high-frequency interval transmission,as they effectively mitigate the challenges associated with maintaining the timeliness of correction parameters.

针刺对急性骨骼肌钝挫伤大鼠肌卫星细胞增殖的影响

目的:观察针刺对急性骨骼肌钝挫伤大鼠卫星细胞增殖的影响。方法:将采用打击装置造成后下肢腓肠肌钝挫伤的大鼠随机分为即刻组、针刺治疗组、自然愈合组。针刺治疗组采用阿是穴针刺疗法,自然愈合组不治疗。结果:针刺治疗组肌卫星细胞核数在大鼠伤后第2天时达高峰,而自然愈合组在伤后第4天达高峰,之后呈下降趋势。在损伤后第1天、第2天、第4天,针刺治疗组大鼠肌卫星细胞核数目均比自然愈合组多,且在损伤后第2天显著高于自然愈合组。结论:大鼠骨骼肌损伤后,针刺能促进肌卫星细胞的增殖并促使活跃期提前出现,促进肌肉再生,加速损伤愈合的进程。

低功率激光对急性骨骼肌顿挫伤大鼠肌卫星细胞增殖活性的影响

目的:观察低功率激光照射对急性骨骼肌顿挫伤大鼠肌卫星细胞增殖活性的影响。方法:将采用打击装置造成后下肢肌群顿挫伤的60只大鼠随机分为激光治疗组(30只)和自然愈合组(30只)。激光治疗组采用美国Erchonia EML(ML2)型低功率激光器对损伤局部进行照射,自然愈合组不进行治疗。通过HE染色光镜、透射电镜观察方法分析低功率激光照射对大鼠急性骨骼肌顿挫伤组织学愈合进程的影响;并通过免疫组织化学方法检测增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)分析低功率激光照射对肌卫星细胞增殖活性的影响。结果:低功率激光照射能加速骨骼肌的再生,促进损伤修复;低功率激光照射对急性骨骼肌顿挫伤大鼠肌卫星细胞有较强的促增殖作用。结论:低功率激光能增强急性骨骼肌顿挫伤大鼠肌卫星细胞增殖活性,从而加速骨骼肌的再生,促进损伤修复。

机械牵拉刺激对大鼠骨骼肌卫星细胞增殖的影响

目的:探讨机械拉伸刺激对骨骼肌卫星细胞增殖能力的影响。方法:通过Flexercell细胞拉伸力学装置对骨骼肌卫星细胞施加5%、15%和25%拉伸应变加载实验,用CCK-8法检测细胞受机械刺激后的增殖变化,采用BCA蛋白测定试剂盒测定细胞总蛋白含量。结果:骨骼肌卫星细胞受机械张力刺激后,发现卫星细胞增殖能力增强,蛋白含量增加,其中,15%拉伸应变率的促增殖与对照组有显著性差异(P<0.01)。结论:机械刺激可以促进体外卫星细胞的增殖能力,细胞增殖能力与细胞所受刺激的负荷大小有关。

运动性损伤后大鼠骨骼肌转化生长因子-β1变化的研究

目的:通过观察大鼠骨骼肌损伤修复过程中TGF-β1基因的表达,研究TGF-β1在运动性骨骼肌损伤修复过程不同时刻的变化特征;方法:健康雄性SD大鼠72只随机分成9组,除对照组外其余各组大鼠以16 m/min的速度,坡度为-16°,进行持续性下坡跑90 min,分别在运动后0 h、6 h、12 h、24 h、48 h、72 h、1周、2周处死、取材。采用RT-PCR和免疫组织化学技术观察大鼠腓肠肌TGF-β1转录和翻译水平的表达;结果:与C组相比,24 h组和2周组大鼠腓肠肌TGF-β1mRNA表达水平明显降低(P<0.05),0 h组、6 h组、72 h组和2周组TGF-β1蛋白表达水平明显降低(P<0.05);结论:运动性骨骼肌损伤修复过程中TGF-β1的表达受到抑制。

不同频率张应变刺激对骨骼肌卫星细胞生长的影响

目的:探讨不同频率机械张应变刺激对骨骼肌卫星细胞形态及细胞增殖指标的影响,为寻找适宜的机械刺激负荷提供实验依据。方法:应用Fx-4000T细胞应变加载系统,时体外培养的大鼠骨骼肌卫星细胞施加15%张应变,频率分别为0 Hz、0.5 Hz、1 Hz和2 Hz,加栽时间为每天6 h,连续4 d;以静置培养的卫星细胞作为对照组。采用流式细胞术检测卫星细胞周期变化,采用RT-ICR技术检测不同频率张应变下膏骼肌卫星细胞MGF mRNA表达水平的变化。结果:张应变刺激后的细胞形态为典型长梭形,且排列呈方向性和规律性。结果:与对照组相比,0.5 Hz、1 Hz和2 Hz组的G_0/G_1期细胞数量显著降低,而0.5 Hz和1Hz组的S+G_2/M期细胞数量显著增加(P<0.05);与0 Hz组相比,0.5 Hz、1 Hz和2 Hz组的G_0/G_1期细胞数量显著降低,而S+G_2/M期细胞数量显著增加(P<0.05)。RT-PCR结果显示,与对照组相比,各实验组的MGF mRNA的表达量均增加。但仅有1 Hz组显著高于对照组(P<0.05)。结论:机械张应变刺激促进骨骼肌卫星细胞的增殖能力和MGF mRNA表达,且与张应变刺激的频率有关,其中1Hz的刺激频率最适宜。

多种微生物搭载返回式卫星的试验研究

利用我国发射的科学返回式卫星，对４ 种具有实际应用价值的真菌、１ 种细菌和３ 种动物病毒的生长及某些特性如产酶、毒力及免疫学等进行了初步研究。结果表明，从４ 株真菌所选育的变异株产酶活性都得到不同程度的提高，但生长速度有的加快，有的则变慢； １ 种动物病毒和１ 种细菌的毒力降低，并能产生较好的免疫原性。

机械生长因子对骨骼肌卫星细胞激活的影响及与其增殖的量效关系

目的:通过离体实验,观察机械生长因子(MGF)对于骨骼肌卫星细胞(SC)的激活作用及促进其增殖的量效关系,探讨MGF对SC在细胞水平的调节机制,为骨骼肌损伤的修复提供理论依据。方法:原代SC取自4周龄雄性SD大鼠双侧的腓肠肌与比目鱼肌。使用不同浓度的MGF干预第三代细胞后测定增殖效果。血清饥饿后通过MGF和DMEM干预骨骼肌卫星细胞,使用流式细胞仪检测其所处细胞周期,判断激活情况。结果:干预48h后,25ng/ml组、50ng/ml组A值显著高于对照组(P<0.01),100ng/ml组、200ng/ml组与对照组之间差异没有显著性(P>0.05);96h后25ng/ml组、50ng/ml组、100ng/ml组、200ng/ml组之间差异没有显著性(P>0.05)。25ng/mlMGF干预G0期的SC24h后MGF组低于对照组(P<0.01)。结论:MGF可以促进SC增殖;MGF可以激活4周龄SD大鼠的G期SC。

微卫星DNA在濒危动物保护中的应用

为了保护珍稀濒危动物,迫切需要了解它的遗传结构和遗传多样性的现状.而微卫星DNA具有多态性信息丰富、共显性遗传、易于检测等特点,作为一种优良的遗传标记在濒危动物研究中得到了广泛的应用.综述了其在濒危动物种群遗传结构分析、基因流程度、种群进化史、物种的判定和种群数量调查、亲缘关系等中的应用情况.