GPS高程及其转换

本文简要介绍了GPS定位的优越性及GPS定位采用的地球(地心)坐标系——WGS 84世界大地坐标系统;GPS测量的大地高与我国采用的正常高系统的高程转换与高程拟合问题等。     

GPS在高程测量中的误差来源及应对措施

本文通过对GPS在高程测量中的误差分析,对提高GPS测量高程精度的方法及措施进行了详细的阐述。     

高程拟合取代水准测量研究

本文主要研究的是GPS高程拟合方面的内容,重点介绍了二次曲面高程拟合模型。。结合对内蒙某矿高程数据水准拟合结果说明利用GPS定位技术,不但可以获取地面点的精密平面坐标,而且,通过建立一定范围内的GPS高程异常模型也可以较精密的拟合地面正常高。其成果很可靠。理论分析和实践检验表明,在平坦地区的局部GPS控制网测量中,GPS高程测量可以逐步代替四等水准测量是可行的。     

试论GPS高程测量技术在矿产勘查中的应用

GPS高程测量的精度,在采用技术手段处理后可以满足地质矿产勘查工作的要求,与传统测量作业相比有着无法替代的优越性。本文通过阐述GPS高程测量原理与实际应用中存在的问题,探讨GPS高程测量在地质矿产勘查应用中的精度问题及解决方法。     

GPS测高的限制性与可行性研究

本文讨论了GPS测高的制约因素,包括GPS测量、大地水准面和高程基准面问题,并从变形监测、实时GPS测量和机器监测与导引三个方面论述了GPS测高的可行性。     

超高压送电线路GPS外控测量中高程的确定

GPS是一种基于卫星定位的系统,在众多领域有着广泛的应用,特别是在现代工程建设中,GPS已成为一个重要的测量工具,能够为工程建设提供较高精度的数据。然而测量高度问题上还有一定的不足之处,有待进一步探索。文章主要对GPS的测量技术作了简要概述,就超高压送电线路GPS外控测量中高程的确定作了一些探讨。     

GPS水准高程拟合精度探讨

近些年来,随着科学技术的不断发展,社会中需要测量平面坐标精度的要求也越来越高。GPS定位技术因为它独有的速度快、精度高以及作业范围大等多种优势,广泛应用于城市内部布设各色形式的控制网、对精密工程的测量以及变形观测等诸多方面。虽然GPSX~平面坐标精度的测量是可靠的,而且能够达到工程所要求的测量标准。但在实践过程和结果中,我们发现,高程数据容易受到不一致的坐标系统的影响,在观测过程中容易产生误差,不能够达到工程的测量标准和需要。由于测量高程数据精度造成的误差和不可靠性,在一定程度上对GPS定位发挥出三维坐标的能力产生了限制。本文就针对如何改进GPS高程测量的精度和方法进行科学合理的探讨。应用GPS的定位技术,找出求定地面点正常高的科学方法,并论述了GPS的水准方法,从中找出了制约这种方法的原因,通过实例详细的阐述了提高精度的主要做法,使GPS定位技术能够在工程领域上发挥更大的作用。     

GPS静态测量和四等水准测量的高程比对

对GPS静态测量的原理和方法进行了探讨,并结合GPS静态测量应用的实际观测结果和四等水准测量高程的比对。     

GPS-RTK高程测量代替四等水准测量的实践

本文简要介绍了GPS高程测量的基本原理、GPS-RTK测量原理以及坐标转换方法等,在此基础上,讨论分析了运用GPS-RTK技术进行高程测量精度的评定方法。分别采用GPS和水准仪对校园网进行测量,得到RTK高程和水准高程数据,计算出点间高差较差和高差较差中误差,并依照评定方法进行比较,分析得出GPS-RTK高程测量能够满足四等水准测量精度要求的结论。运用GPS-RTK技术进行高程测量对测区要求较高,但是其作业效率高,数据精确,所以在部分地区可以代替水准测量,具有很好的应用前景。     

动态GPS（RTK）测量的精度分析

通过动态GPS（RTK）测量和静态GPS测量成果的比较分析,对影响GPS（RTK）测量精度的因素有了充分的了解。总结了影响动态GPS（RTK）精度的原因及解决方法。分析研究表明,动态GPS（RTK）测量平面精度可达到一级导线测量的要求,高程精度可达到等外水准的要求。     

室内GPS发射器角度校准装置的设计与分析

室内GPS利用测量的水平角和垂直角来定位,其测角误差直接影响到系统的综合测量误差,结合室内GPS的测角误差,提出了室内GPS角度校准装置的技术要求,并分别对俯仰角校准和水平角校准所需准确度进行估计,最终利用新型同轴调整装置结合精密转台和竖轴激光导轨研制了一套室内GPS发射器角度校准装置,试验数据表明该装置的俯仰角测量误差小于0．9″,水平角测量误差小于1．6″,解决了室内GPS发射器水平角和俯仰角的校准问题。     

GPS频标比对系统的研制

应用GPS技术研制频标比对系统可对野外环境条件下的通信设备快速地进行时间频率校准.本文详细描述了系统中GPS频率标准源以及比相法、时差法频标比对单元的设计方案和软件设计思路,并给出了设计方案中关键技术解决的途径.该系统经校准完全能够满足要求,并在计量技术机构范围中得到应用.     

Adaptive neuro-fuzzy module for inertial navigation system/global positioning system integration utilising position and velocity updates with real-time cross-validation

Recently, methods based on artificial intelligence (AI) have been suggested to provide reliable positioning information for different land vehicle navigation applications. The majority of these applications utilise both the global positioning system (GPS) and the inertial navigation system (INS). These AI modules were trained to mimic the latest vehicle dynamics so that, in case of GPS outages, the system relies on INS and the recently updated AI module to provide the vehicle position. Several neural networks and neuro-fuzzy techniques were implemented in real-time in a de-centralised fashion and provided acceptable accuracy for short GPS outages. It was reported that these methods provided poor positioning accuracy during relatively long GPS outages. In order to prevail over this limitation, this study optimises the Al-based INS/GPS integration schemes utilising adaptive neuro-fuzzy inference system with performing, in real-time, both GPS position and velocity updates. In addition, a holdout cross validation method during the update procedure was utilised in order to ensure generalisation of the model. The proposed system is tested using differential GPS and both navigational and tactical grades INS field test data obtained from a land vehicle experiment. The results showed that the effectiveness of the proposed system over both the existing Al-based and the conventional INS/GPS integration techniques, especially during long GPS outages. This method may have one limitation related to the unusual significant changes of the vehicle dynamics between the update and the prediction stages of operation which may influence the overall positioning accuracy.     

Correlation between antenna radiation pattern and field performance for global positioning systems in telematics as a function of antenna placement

The effect of antenna placement on the global positioning system (GPS) performance in telematics is investigated. Two sets of measurements were conducted. The first set consisted of measuring the vehicle-level antenna radiation pattern at three distinct antenna locations on a sedan vehicle. The second set consisted of a series of drive tests in three distinct driving environments. The field data were collected in parallel for each antenna location in all driving environments. GPS availability and accuracy results from the field testing are correlated to the vehicle-level antenna radiation pattern measurements. Results are presented to show the impact of the antenna placement on the GPS system performance and to demonstrate the good correlation between the vehicle-level radiation pattern measurements and the performance in the field.     

地方时间标准建立方案的研究

为满足卫星导航产品的检测需求,提出由国家时间基准驾驭的地方时间标准的建立方案,建立GPS共视法时间传递系统。通过数据比对使本地原子钟溯源到中国计量院的时间基准UTC(NIM),对比对数据用Vondrak平滑法进行滤波,并剔除异常数据。研究了影响比对精度的因素,包括:双频实测电离层时延,天线坐标设为固定模式,仰角选择30°以上计算,进一步提高了比对精度。作出预估方程,实现了实时的量值传递。实验结果表明,生成的地方时间标准与国家时间基准同步在±10 ns以内,并且提高了时标的准确性和稳定性。     

A simple spatial integration scheme for solving Cauchy problems of non-linear evolution equations

In this study, we address a new and simple non-iterative method to solve Cauchy problems of non-linear evolution equations without initial data. To start with, these ill-posed problems are analysed by utilizing a semi-discretization numerical scheme. Then, the resulting ordinary differential equations at the discretized times are numerically integrated towards the spatial direction by the group-preserving scheme (GPS). After that, we apply a two-stage GPS to integrate the semi-discretized equations. We reveal that the accuracy and stability of the new approach is very good from several numerical experiments even under a large random noisy effect and a very large time span.     

A Hybrid Particle Approach for GNSS Applications With Partial GPS Outages

To provide an accurate positioning, the land vehicle navigation applications are based on global positioning system (GPS). The addition of a digital road map allows locating the vehicle continuously and helps the driver to get the best path. These systems are usually enhanced with dead reckoning sensors due to GPS outages in urban areas in particular. For instance, the odometer sensors can be used to correct the vehicle location in this case. We present here a global estimation method of solving the fusion problem of the GPS, odometer, and digital road map measurements in the presence of GPS outages. It relies on a hybrid filter that takes advantage of the combination of a Kalman filter, which computes the linear part of the state equations and a particle filter to provide an optimal resolution scheme. When GPS fails, the filter fuses all available pseudorange measures to improve the vehicle positioning. In the case of an urban transport scenario, the results show that the number of particles is significantly reduced to achieve the same performance of a single particle filter in terms of accuracy. Moreover, software solutions can be developed for real-time applications.      

一种水下GPS系统及其在蛙人定位导航中的应用

研究了一种适用于蛙人导航的水下GPS系统。针对蛙人执行水下任务所需的高精度导航,提出了一种由主动声纳浮标作为定位基站的GPS定位系统,介绍了该系统基于延时测量的定位原理和求解方法,给出了Kalman滤波器和扩展Kalman滤波器的设计,并通过数值仿真进行了验证,结果表明：为提高定位精度,在定位解算的基础上进行滤波平滑是必要的。     

产品几何技术规范在模型定义中的应用

针对基于模型的数字化定义（MBD）在产品几何定义与检测一致性评定中的问题,提出将产品几何技术规范（GPS）理论应用于模型定义中,基于GPS中的对偶性原则建立了应用的解决方案,分析了GPS在模型定义中应用的关键技术,通过面齿轮模型定义实例,来说明GPS在MBD中具体应用,结合面齿轮齿面精度评价实例,说明了GPS技术的应用对产品评定的影响,为GPS和MBD结合应用提供了一种思路.