A Method for Detecting Adhesive Related-Factors of Streptococcus suis Serotype 2 by Real-time PCR

[Objective] This study aimed to establish a method for quantitative detection of mRNA transcriptional level of SS2 adhesive related-factors of Streptococcus suis serotype 2 （SS2） by fluorescent quantitative PCR. []Vlethod] The gene fragments en- coding SS2 adhesive related-factors MRP, FBPS and CPS2J and a housekeeping gene aroA were amplified by reverse transcription PCR from the total RNA of SS2, cloned, and sequenced. The recombinant plasmids containing the target genes were constructed, and used as templates in Real-time PCR. [Result] Dynamic curves, stan- dard curves and melting curves of the adhesive related-factors and aroA were ob- tained by the optimized Real-time PCR system. The standard curves showed a good linear relationship between template copy number and circulation number, and the correlation coefficients （FF） of the standard curves were over 0.995. Also, these as- says were highly specific a^d there was single specific melting peak for every gene. Moreover, the assays were highly sensitive and had a detection limit of 1.0×102 copies in 1 μl of initial templates. Finally, it was highly repeatable and had a coeffi- cient of variation less than 2% for intra-assay. [Conclusion] This study will provide a way to reveal the adhesion mechanism of SS2 to different host cells at molecular level.

GPS VEHICLE NAVIGATION SYSTEM

This paper introduces the GPS intelligent vehicle navigation system (IVNS). This system can be widely applied to the urban fields, inter province and inter state transport which, as a part of intelligent transport systems(ITS), would contribute toward improving troublesome driving conditions on driver′s benefits. The paper discuss as two key techniques: city geographical information system(GIS), real time correction of the deviation.

An efficiency algorithm on Gaussian mixture UKF for BDS/INS navigation system

To further improve the performance of UKF(Unscented Kalman Filter) algorithm used in BDS/SINS(BeiDou Navigation Satellite System/Strap down Inertial Navigation System), an improved GM-UKF(Gaussian Mixture Unscented Kalman Filter) considering non-Gaussian distribution is discussed in this paper. This new algorithm using SVD(Singular Value Decomposition) is proposed to alternative covariance square root calculation in UKF sigma point production. And to end the rapidly increasing number of Gaussian distributions, PDF(Probability Density Function) re-approximation is conducted. In principle this efficiency algorithm proposed here can achieve higher computational speed compared with traditional GM-UKF. And simulation experiment result show that, compared with UKF and GM-UKF algorithm, new algorithm implemented in BDS/SINS tightly integrated navigation system is suitable for handling nonlinear/non-Gaussian integrated navigation position calculation, for its lower computational complexity with high accuracy.

Value of virtual bronchoscopic navigation and transbronchial ultrasound-guided sheath-guided exploration in diagnosis of peripheral lung cancer

BACKGROUND Peripheral lung cancer poses a substantial harm to human health,and it is easy to become exacerbated,potentially threatening the life and safety of patients AIM To assess the value of virtual bronchoscopic navigation(VBN)combined with transbronchial ultrasound-guided sheath-guided(EBUS-GS)exploration in the diagnosis of peripheral lung cancer.METHODS A total of 236 patients with peripheral lung cancer(nodule diameter range,8-30 mm;diagnosed using high-resolution computed tomography)were selected from three centers between October 2018 and December 2019.Patients who underwent EBUS-GS exploration alone were included in a control group,and those who received VBN in combination with EBUS-GS exploration were included in an observation group.The diagnostic rate and total operating time of differentsubgroups of the two groups were compared,and the time needed to determine the lesion was recorded.RESULTS There were no significant differences in diagnosis rate or total operation time between the two groups(P>0.05),and the time needed to determine the lesion in the observation group was less than that of the control group(P<0.05).CONCLUSION The combined use of VBN and EBUS-GS exploration technology has little effect on the diagnosis rate and total operation time of peripheral lung cancer,but it significantly shortens the time needed to determine the lesion and is a valuable diagnostic method.

Real-time virtual sonography visualization and its clinical application in biliopancreatic disease

AIM:To evaluate the usefulness of real-time virtual sonography(RVS)in biliary and pancreatic diseases.METHODS:This study included 15 patients with biliary and pancreatic diseases.RVS can be used to observe an ultrasound image in real time by merging the ultrasound image with a multiplanar reconstruction computed tomography(CT)image,using pre-scanned CT volume data.The ultrasound used was EUB-8500with a convex probe EUP-C514.The RVS images were evaluated based on 3 levels,namely,excellent,good and poor,by the displacement in position.RESULTS:By combining the objectivity of CT with free scanning using RVS,it was possible to easily interpret the relationship between lesions and the surrounding organs as well as the position of vascular structures.The resulting evaluation levels of the RVS images were12 excellent(pancreatic cancer,bile duct cancer,cholecystolithiasis and cholangiocellular carcinoma)and 3 good(pancreatic cancer and gallbladder cancer).Compared with conventional B-mode ultrasonography and CT,RVS images achieved a rate of 80%superior visualization and 20%better visualization.CONCLUSION:RVS has potential usefulness in objective visualization and diagnosis in the field of biliary and pancreatic diseases.

Precise Point Positioning Technique with IGS Real-Time Service (RTS) for Maritime Applications

The maritime navigation accuracy requirements for radionavigation systems such as GPS are specified by the International Maritime Organization (IMO). Maritime navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with an accuracy requirement that ranges from 10 m to 0.1 m. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP) and with the advent of the new IGS-Real-Time-Service (RTS), it is necessary to assess the possibility of a wider role of the PPP-based positioning technique in maritime applications. This paper investigates the performance of an autonomous real-time PPP-positioning solution by using the IGS- RTS service for maritime applications that require an accurate positioning system. To examine the performance of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is investigated. It is shown that the real-time IGS-RTS PPP-based GPS positioning technique fulfills IMO requirements for maritime applications with an accuracy requirement ranges from 10 m for Ocean/Coastal/Port approach/Inland waterways navigation to 1.0 m for in port navigation but cannot fulfill the automatic docking application with an accuracy requirement of 0.10 m. To further investigate the real-time PPP-based GPS positioning technique, a comparison is made between the real-time IGS-RTS PPP-based positioning technique and the real-time PPP-based positioning by using the predicted part of the IGS Ultra-Rapid products and the real-time GPS positioning technique with the Wide Area Differential GPS service (WADGPS). It is shown that the IGS-RTS PPP-based positioning technique is superior to the IGS-Ultra-Rapid PPP-based and WADGPS-based positioning techniques.

Satellite-station time synchronization information based real-time orbit error monitoring and correction of navigation satellite in Beidou System

Satellite-station two-way time comparison is a typical design in Beidou System(BDS)which is significantly different from other satellite navigation systems.As a type of two-way time comparison method,BDS time synchronization is hardly influenced by satellite orbit error,atmosphere delay,tracking station coordinate error and measurement model error.Meanwhile,single-way time comparison can be realized through the method of Multi-satellite Precision Orbit Determination(MPOD)with pseudo-range and carrier phase of monitor receiver.It is proved in the constellation of 3GEO/2IGSO that the radial orbit error can be reflected in the difference between two-way time comparison and single-way time comparison,and that may lead to a substitute for orbit evaluation by SLR.In this article,the relation between orbit error and difference of two-way and single-way time comparison is illustrated based on the whole constellation of BDS.Considering the all-weather and real-time operation mode of two-way time comparison,the orbit error could be quantifiably monitored in a real-time mode through comparing two-way and single-way time synchronization.In addition,the orbit error can be predicted and corrected in a short time based on its periodic characteristic.It is described in the experiments of GEO and IGSO that the prediction accuracy of space signal can be obviously improved when the prediction orbit error is sent to the users through navigation message,and then the UERE including terminal error can be reduced from 0.1 m to 0.4 m while the average accuracy can be improved more than 27%.Though it is still hard to make accuracy improvement for Precision Orbit Determination(POD)and orbit prediction because of the confined tracking net and the difficulties in dynamic model optimization,in this paper,a practical method for orbit accuracy improvement is proposed based on two-way time comparison which can result in the reflection of orbit error.

地月空间基础设施体系架构与发展设想

建设地月空间基础设施,为人类在地月空间的活动提供基础性、通用性的通信、导航、监测等服务,既可满足中国后续月球探测国家重大工程任务需求,同时可以加速推进地月空间航天产业发展,对于推动中国科技强国、航天强国建设具有重大的战略意义。在阐明地月空间基础设施概念、分析研判国内外发展现状的基础上,紧密围绕重大工程和航天产业持续性发展需求,提出地月空间基础设施体系架构设想,明确系统服务、系统组成、“云-域-端”网络体系以及内部和用户接口体系。最后以分阶段逐步建成技术先进、布局合理的地月空间基础设施,提供自主开放、安全可靠、长期连续稳定运行的通用化服务为目标,提出发展展望和发展建议,为中国地月空间基础设施发展建设规划提供参考。

Time-asynchrony identification between inertial sensors in SIMU

Traditional strapdown inertial navigation system （SINS） algorithm studies are based on ideal measurements from gy- ros and accelerometers, while in the actual strapdown inertial measurement unit （SIMU）, time-asynchrony between each iner- tial sensor is inevitable. Testing principles and methods for time- asynchrony parameter identification are studied. Under the single- axis swaying environment, the relationships between the SINS platform drift rate and the gyro time-asynchrony are derived using the SINS attitude error equation. It is found that the gyro time- asynchrony error can be considered as a kind of pseudo-coning motion error caused by data processing. After gyro testing and synchronization, the single-axis tumble test method is introduced for the testing of each accelerometer time-asynchrony with respect to the ideal gyro triad. Accelerometer time-asynchrony parame- ter identification models are established using SINS specific force equation. Finally, all of the relative time-asynchrony parameters between inertial sensors are well identified by using fiber optic gyro SIMU as experimental verification.

GRACE time-varying gravity field solutions based on PANDA software

The conventional dynamic approach for gravity filed modelling has been implemented in the PANDA(Position and Navigation Data Analyst) software. A variant of the so-called ’two-step’ method for gravity field modelling is adopted for this purpose, where the GRACE(Gravity Recovery and Climate Experiment)orbits are derived from the GPS(Global Positioning System) data in a first step followed by a simultaneous determination of dynamic orbit and gravity filed from the GPS-derived orbits and K-band rangerate measurements in a second step. In this way, the monthly gravity field solutions complete to degree and order 96 are produced for the period Jan. 2005 to Dec. 2010. Their performance is assessed by comparing them with the official solutions, i.e., CSR RL05, GFZ RL05 a and JPL RL05. A comparison in the spectral domain in terms of geoid heights reveals that the obtained solutions present the smallest degree amplitudes at degree 30-75. A further analysis of mass changes in the spatial domain demonstrates that the main signals observed from the obtained solutions are in great agreement with those from the official solutions. Remarkably, the correlation coefficients of mass changes in large river basins from the official solutions with respect to those from the obtained solutions are all above 0.97. These results demonstrate that the obtained solutions are comparable to the official solutions.

一种单信标测距辅助INS的导航方法

传统基于地球物理场的匹配辅助惯性导航方法在基础数据变化特征不明显或数据缺乏等苛刻条件下,难以实现有效匹配定位。为解决这一问题,提出了一种单信标测距辅助惯性导航系统(INS)的方法。首先,在单信标测距解析基准图上引入相关极值匹配辅助导航算法并进行重新建模。然后,采用差分进化寻优算法对该模型进行解算,并设计了一种固定匹配序列长度的建模方法以解决相关极值匹配算法实时性差的缺点。所提方法在缺乏地球物理基础数据条件下,仅需在海底布放单只声信标即可实现局部海域水下高精度实时定位。同时,由于采用的测距基准图为解析形式,所提方法也能较好地解决离散匹配算法定位精度受限于基准图分辨率等问题。最后,设计了相关实测实验,实验结果表明当惯导定位误差累积为1529.4 m时,采用所提方法与单信标匹配,定位误差减小为111.8 m,算法的有效性得到了验证。

北斗PPP-B2b与CNES实时产品性能的比较与评估

为分析PPP-B2b的实际服务性能,采用为期30 d的PPP-B2b数据与国际全球导航卫星系统(global navigation satellite system,GNSS)服务组织测站数据以及2021年12月16日的海上船载动态数据,进行了轨道与钟差的精度评估、实时精密单点定位(precise point positioning,PPP)的定位性能测试,并与采用法国国家太空中心(centre national d′etudes spatiales,CNES)存档产品CNT的相应结果进行比较。结果表明:PPP-B2b服务的北斗三号系统(BeiDou navigation satellite system phaseⅢ,BDS-3)与全球定位系统(global positioning system,GPS)轨道的径向精度分别为0.07 m、0.089 m,低于CNT 0.041 m和0.025 m。而BDS-3的钟差精度为0.029 m,与GPS钟差精度接近,优于CNES BDS-3的钟差精度0.057 m。基于PPP-B2b服务的静态定位测试中,BDS-3和BDS-3+GPS平均收敛时间小于20 min,优于单GPS系统,且收敛后精度更高。而在动态测试中,BDS-3和BDS-3+GPS组合东北天(north,east and up,NEU)方向均方根(root mean square,RMS)均优于11 cm,单GPS优于26 cm。在海上实际测试中,PPP-B2b的BDS-3+GPS组合NEU方向RMS分别为0.028 m、0.074 m、0.081 m,收敛时间为12.4 min。

量子传感(Ⅲ):核心应用与未来展望

作为量子信息感知物理实现基础的量子传感技术是三大核心量子技术之一,也是发展历史最悠久、技术成熟度最高、实际应用范围最广、潜在应用最多的量子技术。文章是量子传感系列综述的第三部分,在前两部分内容的基础上,从实际应用角度出发,介绍量子传感技术在导航定位授时、遥感探测、生物医学和基础物理等代表性领域的应用现状,阐述了量子传感的阶段性发展特征,包括量子传感的核心使能组件、量子传感的适应性难题等,最后,结合从传感到信息感知的论述,给出了量子传感技术的未来展望。

双层虚拟垂线时差法流量计算模型实证研究

为提高天然河道河流流量在线监测精度,基于超声波时差法多层测流技术,提出并构建了双层虚拟垂线时差法流量计算模型,对江苏省秦淮新河水利枢纽泄洪期进行了计算,并与同期开展的走航ADCP流量比测结果进行对比分析。结果表明,该双层虚拟垂线时差法流量计算方法在一定程度上克服了由于天然河道水情条件复杂而导致率定期长的难题,河道流量测验精度高,计算的泄洪期河道流量与走航ADCP测量数据基本一致,相关系数为0.999,相对误差均在15%以内,在一定程度上能够满足洪水期河道流量测验精度要求。

LEO多星座增强BDS精密单点定位性能评估

针对不同构型的低轨星座(LEO)增强北斗卫星导航系统BDS的精密单点定位PPP性能开展研究。通过IGS高、中、低纬度6测站实测数据、精密轨道及钟差产品,生成BDS、“鸿雁”HY、“微厘空间”CS精密星历、卫星钟差、观测量等实验仿真数据,构建了LEO增强BDS PPP数学模型,实现了BDS、BDS+HY、BDS+CS、BDS+HY+CS不同组合PPP。实验结果表明,在10、60 min静态PPP定位精度以及平均可视卫星数、PDOP值等方面均有不同程度的提升,HY对高纬度KIRU站改善效果显著,收敛时间减至2 min以内,CS对低纬度FAA1站测站收敛时间的提升最大,从46 min 50 s缩短至2 min,HY+CS增强BDS的效果最好,10 min定位精度均能达到毫米级,除FAA1站外其他测站均收敛在1 min以内。

广播星历旋转误差对低轨星载BDS-3/GPS实时精密定轨影响分析

基于LT-01A卫星星载BDS-3/GPS观测值进行了星载实时精密定轨研究,并重点分析了广播星历旋转误差对实时定轨精度的影响。通过赫尔默特转换评估了所选时段内GPS和BDS-3广播星历轨道旋转误差,显示BDS-3广播星历旋转误差可达-8.7 mas,平均量级较GPS大约2.5倍。BDS-3广播星历经旋转改正后,轨道切向、法向均方根(RMS)误差从25 cm左右提升至10 cm量级,提升幅度超过50%。因此,基于星载BDS-3以及BDS-3/GPS联合的实时定轨精度受BDS-3星历旋转误差影响严重,且主要作用于切向和法向。经过旋转改正后,单独BDS-3实时定轨在切向、法向、径向RMS分别为21.0 cm、10.7 cm及11.2 cm,其切向和法向精度比改正前分别提升15.0%和31.8%;BDS-3与GPS联合定轨进一步提升切向精度至19.4 cm。得益于BDS-3广播星历较高的精度,单BDS-3以及BDS-3/GPS联合的实时定轨在旋转改正前的三维RMS分别为31.9 cm和29.2 cm,较单GPS实时定轨分别提升9.1%和16.8%;添加旋转改正后,其定轨精度分别提升至26.7 cm和25.0 cm,较单GPS实时定轨分别提升22.6%和27.5%。

一种双天线GNSS接收机混合干扰抑制方法

相对于单天线GNSS接收机,阵列GNSS接收机具有空间分辨能力,当干扰信号与卫星信号在时域频域上产生混叠时,其能够从空域上对干扰信号进行抑制,具有更强的干扰抑制能力。但阵列GNSS接收机相对于单天线GNSS接收机需要更多的阵元,随着阵元数目的增加,系统成本也相应的增加,限制了阵列GNSS接收机的应用范围。双天线GNSS接收机既具有空域抗干扰能力,同时又具有价格低廉的特点,是一种较好的折中选择。对于单一的连续波干扰,其能够产生很好的抑制效果,但是当连续波干扰中混有脉冲干扰时,由于受到自由度的限制,双天线GNSS接收机无法对混合干扰进行有效抑制,进而影响接收机的正常工作。针对于上述问题,本文提出一种新的混合干扰抑制算法。首先利用脉冲的时域特征,对待处理信号进行分块处理,确保至少有一个数据块中不含有脉冲干扰,随后对不含脉冲干扰的数据块,使用空时最小功率(Space-Time Adaptive Processing Power Inversion,STAP-PI)算法得到最优权值,然后利用该权值抑制原信号中的连续波干扰。最后,对处理之后信号中残余的脉冲干扰进行时域置零处理,从而达到抑制混合干扰的目的。仿真实验和实采实验结果均证明了所提算法的有效性。

滤波器阶数对导航接收机时域抗干扰的影响研究

随着电磁环境恶化以及干扰强度和复杂度的升级,对导航接收机的抗干扰能力提出了更高的要求。针对目前导航接收机对滤波器阶数缺乏深入研究的现状,文中从时域自适应滤波器的阶数入手,对其抗干扰性能进行了研究。然后对不同干扰环境下的滤波器级抗干扰性能进行了分析,提出了一种基于抗干扰需求的最优阶数设计方法。仿真结果显示,适当增大滤波器的长度,可提高其抗干扰的能力,在工程实践中可以针对具体的抗干扰要求来优化滤波器的阶数。

电磁导航支气管镜引导下肺结节定位和CT引导下Hook-wire穿刺定位在肺癌根治术中的应用效果及安全性比较

目的对比电磁导航支气管镜(ENB)引导下肺结节定位和CT引导下Hook-wire穿刺定位在肺癌根治术中的应用效果和安全性。方法将87例行肺癌根治术患者根据定位方式的不同分为CT组(n=45,行CT引导下Hook-wire穿刺定位)和ENB组(n=42,行ENB引导下肺结节定位)。比较两组患者手术情况、切缘阳性率、心肺功能指标、应激指标和并发症发生情况。结果ENB组患者定位时间、定位后等待时间均短于CT组,差异均有统计学意义(P﹤0.05)。术后7天,两组患者左心室射血分数(LVEF)、每搏量(SV)、用力肺活量(FVC)均较术前降低,但ENB组患者LVEF、SV、FVC均高于CT组,差异均有统计学意义(P﹤0.05)。术后1天,两组患者白细胞介素-6(IL-6)、白细胞介素-8(IL-8)、C反应蛋白(CRP)、皮质醇(Cor)水平均较术前升高,但ENB组患者IL-6、IL-8、CRP、Cor水平均低于CT组,差异均有统计学意义(P﹤0.05)。两组患者并发症总发生率比较,差异无统计学意义(P﹥0.05)。结论相比于CT引导下Hook-wire穿刺定位,ENB引导下肺结节定位的定位时间和定位后等待时间更短,能够更加有效地改善患者的心肺功能,减轻应激反应。

改进BIC的GNSS站坐标时序有色噪声特性分析

为了有效解决传统的极大似然估计方法存在的未知数多导致结果不准确的问题,提出一种改进BIC的GNSS站坐标时序有色噪声特性分析方法:选取全球范围内100个基准站2008—2022年坐标时序及仿真的100组坐标时序,采用赤池信息准则(AIC)、贝叶斯信息准则(BIC)、改进的贝叶斯信息准则(BIC_tp)对不同有色噪声模型进行噪声特性分析,获取基准站坐标序列的最优噪声模型及速度参数;探讨BIC_tp对噪声模型及速度估计的影响。结果表明,基准站坐标序列噪声模型呈现出多样性特征,在北(N)和东(E)方向主要表现为闪烁噪声+白噪声(FNWN)模型,天顶(U)方向主要表现为幂律噪声+白噪声(PLWN)模型;相比于AIC和BIC噪声模型估计准则,BIC_tp方法对有色噪声模型估计具有较高的准确性,尤其是闪烁噪声+随机游走噪声(RW)+白噪声(FNRWWN)模型对全球卫星导航系统(GNSS)站速度不确定度的影响在N与E方向远大于U方向;正确获取模型参数估计的实际不确定度及改正噪声分量对于合理应用GNSS坐标时间序列数据具有重要意义。