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1.
通过实测资料说明,在较为平坦和开阔地区的地形科中,在不需提高测量成本的情况下,按ＧＰＳ测量最基本的操作要求,ＧＰＳ平面和高程精度均可满足测图精度要求。 相似文献
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利用GPS单点定位数据求解高程的新方法 总被引：1，自引：0，他引：1
全球定位系统可用于测定很精确的三维（水平位置和高程）大地坐标，但其中第三个坐标不能用在测量工程方面，因为这是ＧＰＳ参考系的量，而用水准测量测定的高程是相对于大地水准面的量。为了将ＧＰＳ用于精密高程传递，必需将ＧＰＳ高差转换为正高高差，本文提出两种确定大地水准面倾斜的新方法以及对一个隧洞控制网求出的结果。 相似文献
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当前利用多旋翼无人机倾斜摄影建立三维模型,已在大比例尺地形测图中广泛应用,相较于传统数字测图,其作业方式和效率均有了很大改变。本文采用飞马多旋翼无人机,搭载D-OP3000倾斜摄影模块,在某低山丘陵地貌区域获取高精度倾斜摄影数据后,利用Context Capture软件进行空三加密和三维建模,并采用山维科技EPS软件进行立体测图;同时对倾斜摄影和垂直摄影在免像控和有像控点不同方案的精度进行比较,验证了免像控方案空三精度、模型分辨率及地形测量成果质量能满足1∶1000比例尺地形图精度要求,有像控点方案高程精度较高,可满足1∶500大比例尺地形测图和土方工程量计算精度要求。 相似文献
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随着数字摄影测量技术从单机工作方式向系统集成的工作方式转变,处理空间数据获得数字正射影像(DOM)已较为容易。但传统大比例尺城市DOM中存在建筑物倾斜、变形等问题,很难直接利用DOM进行精确测图。本文为解决传统DOM量测问题,提出可量测的影像高程同步模型(OESM),利用数字高程模型(DEM)和数字表面模型(DSM)获取DOM每个单元的高程信息,以还原真实三维场景。在OESM模型的基础上,DOM不仅可以实现"单片"精确测图功能,还可利用高程信息直接应用于大比例尺城市测图中的建筑物重建,避免传统摄影测量立体测图引起的繁复操作,提高人力测图效率。文中利用真实航空影像和点云数据(25pts/m2)进行了建筑物屋顶角点的OESM单片量测,试验结果表明利用OESM模型测图精度可靠。 相似文献
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本文针对山区施测常规水准比较困难的现状,以及求取高程异常（差）的常规重力法、几何法和混合法在山区的局限性,提出了顾及地形起伏的ＧＰＳ／三角测高方法。文中介绍了ＧＰＳ／三角测高的原理以及实现技术和精度分析等问题,最后对该方法在隧道（洞）高程控制中的应用及其效果作了阐述。 相似文献
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无人机倾斜摄影测量在三维模型测图中的应用 总被引：1，自引：0，他引：1
针对传统大比例尺测图存在人工成本高、外业工作量大、效率低等问题，本文提出了通过无人机倾斜摄影测量，利用ContextCapture进行实景三维建模，运用PSG软件实现裸眼三维测图的方法。以湖南省桂阳县欧阳海镇为例，进行了1：500大比例尺地籍测图，并对精度进行了验证。结果表明，检测点平面位置中误差为0.046 m，检测点高程中误差为0.048 m，小于规范要求的0.05 m。综上所述，成果满足1：500地籍测图精度要求，该方法能够提高测图作业的效率。 相似文献
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海洋测量中的DGPS技术及实践 总被引：1，自引：0，他引：1
海洋测量中的ＤＧＰＳ技术及实践梁开龙，暴景阳，王建文（大连舰艇学院，１１６０１８）１引言近年来，在海洋测量中已愈来愈多地使用ＧＰＳ进行定位。在小比例尺的海洋测图中，采用ＧＰＳ单点定位方式就可以满足精度要求、而对于大比例尺海洋测量和海上工程定位则必须采... 相似文献
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《测绘通报》1965,(4)
问：在1:1万航测外业规范第12页§8中规定图上高程注记点的高程中误差（见表2）及等高线的高程中误差都比1959年出版的平版仪规范中（第11、12页）的相应规定有所放宽,这样规定的依据是什么？答：考虑到平板仪测图时,所有高程注记点,都是在野外用仪器直接测定的点,但采用航测方法成图时,不少高程注记点是由航测内业在野外控制的基础上,再进行加密求得的,有的高程注记点还是在立体测图时测定的,它们受所使用仪器量测精度的限制,有的误差还增加得比较多（如山地用多倍仪）,所以在两种规范上对高程注记点分别作了精度规定,而把航测的规定得宽一些（当然这只是就实测的点而言,如就整个精度来讲,则航测较平板仪测图要高）。至于等高线的高程中误差,两者已趋于一致,可参看航测外业规范第13页表3及平板仪规范补充规定第5页之8。 相似文献
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A New Solar Radiation Pressure Model for GPS Satellites 总被引：11，自引：3，他引：8
The largest error in currently used GPS orbit models is due to the effect of solar radiation pressure. Over the last few years
many improvements were made in modeling the orbits of GPS satellites within the International GPS Service (IGS). Howeer, most
improvements were achieved by increasing the number of estimated orbit and/or solar radiation pressure parameters. This increase
in the number of estimated satellite parameters weakens the solutions of all estimated parameters (not only orbit parameters).
Because of correlations the additional orbit parameters may introduce biases in other estimated quantities, for example the
length of day. We present a recently developed solar radiation pressure model for the GPS satellites. This model is based
on experiences and results gained at the Center for Orbit Determination in Europe (CODE) in the context of its IGS activities
since June 1992. The performance of the new model is almost an order of magnitude better than that of the existing ROCK models.
It also allows a reduction of the number of orbit parameters that have to be estimated. ? 1999 John Wiley & Sons, Inc. 相似文献
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GPS technology will face not one but two critical rollover dates over the next eight months. One is the millennium (Y2K) rollover.
The other is the GPS week 1024 rollover also known as the GPS End of the Week (EOW). Each rollover dat has the potential to
cause severe problems in GPS receivers and related software. This article expolres the reasons why these dates are a problem
and describes choices that must be made as to their solution. The paper also describes some verification methods that may
be used to test GPS receivers and software. ? 1999 John Wiley & Sons, Inc. 相似文献
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GPS-RTK技术在地籍测量中的应用 总被引：1，自引：0，他引：1
段曙光 《测绘与空间地理信息》2010,33(1):107-109
随着近些年GPS RTK技术的出现以及GPS空间定位精度的不断提高,GPS RTK已被广泛地应用于控制测量、地籍测量、地形图测量中。本文结合地籍测绘工作实践重点介绍了RTK技术的基本原理、优势以及应用注意的问题等,可见GPS RTK技术在确保测量成果精度可靠性的前提下,很大程度上提高测图作业效率的明显优势。 相似文献
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王解先 《地球空间信息科学学报》2009,12(2):95-99
Orbit fitting is used in many GPS applications. For example, in Precise Point Positioning (PPP), GPS orbits (SP3 orbits) are normally retrieved either from IGS or from one of its Analysis Centers (ACs) with 15 minutes’ sampling, which is much bigger than the normal observation sampling. Therefore, algorithms should be derived to fit GPS orbits to the observation time. Many methods based on interpolation were developed. Using these methods the orbits fit well at the sampling points. However, these methods ig... 相似文献
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Orbit fitting is used in many GPS applications. For example, in Precise Point Positioning (PPP), GPS orbits (SP3 orbits) are normally retrieved either from IGS or from one of its Analysis Centers (ACs) with 15 minutes’ sampling, which is much bigger than the normal observation sampling. Therefore, algorithms should be derived to fit GPS orbits to the observation time. Many methods based on interpolation were developed. Using these methods the orbits fit well at the sampling points. However, these methods ignore the physical motion model of GPS satellites. Therefore, the trajectories may not fit the true orbits at the periods in between 2 sampling epochs. To solve this problem, we develop a dynamic approach, in which a model based on Helmert transformation is developed in GPS orbit fitting. In this orbit fitting approach, GPS orbits at sampling points are treated as pseudo-observations. Thereafter, Helmert transformation is built up between the pseudo-observations and dynamically integrated orbits at each epoch. A set of Helmert parameters together with corrections of GPS initial orbits are then modeled as unknown parameters. Results show that the final fit orbits have the same precision as the IGS final orbits. 相似文献
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Local geoid determination combining gravity disturbances and GPS/levelling: a case study in the Lake Nasser area, Aswan, Egypt 总被引：1，自引：0，他引：1
C. C. Tscherning Awar Radwan A. A. Tealeb S. M. Mahmoud M. Abd El-Monum Ramdan Hassan I. El-Syaed K. Saker 《Journal of Geodesy》2001,75(7-8):343-348
The use of GPS for height control in an area with existing levelling data requires the determination of a local geoid and
the bias between the local levelling datum and the one implicitly defined when computing the local geoid. If only scarse gravity
data are available, the heights of new data may be collected rapidly by determining the ellipsoidal height by GPS and not
using orthometric heights. Hence the geoid determination has to be based on gravity disturbances contingently combined with
gravity anomalies. Furthermore, existing GPS/levelling data may also be used in the geoid determination if a suitable general
gravity field modelling method (such as least-squares collocation, LSC) is applied. A comparison has been made in the Aswan
Dam area between geoids determined using fast Fourier transform (FFT) with gravity disturbances exclusively and LSC using
only the gravity disturbances and the disturbances combined with GPS/levelling data. The EGM96 spherical harmonic model was
in all cases used in a remove–restore mode. A total of 198 gravity disturbances spaced approximately 3 km apart were used,
as well as 35 GPS/levelling points in the vicinity and on the Aswan Dam. No data on the Nasser Lake were available. This gave
difficulties when using FFT, which requires the use of gridded data. When using exclusively the gravity disturbances, the
agreement between the GPS/levelling data were 0.71 ± 0.17 m for FFT and 0.63 ± 0.15 for LSC. When combining gravity disturbances
and GPS/levelling, the LSC error estimate was ±0.10 m. In the latter case two bias parameters had to be introduced to account
for a possible levelling datum difference between the levelling on the dam and that on the adjacent roads.
Received: 14 August 2000 / Accepted: 28 February 2001 相似文献
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A closed-form formula for GPS GDOP computation 总被引：7，自引：2，他引：5
Shing H. Doong 《GPS Solutions》2009,13(3):183-190
Geometric dilution of precision (GDOP) is often used for selecting good satellites to meet the desired positioning precision.
An efficient closed-form formula for GDOP has been developed when exactly four satellites are used. It has been proved that
increasing the number of satellites for positioning will always reduce the GDOP. Since most GPS receivers today can receive
signals from more than four satellites, it is desirable to compute GDOP efficiently for the general case. Previous studies
have partially solved this problem with artificial neural network (ANN). Though ANN is a powerful function approximation technique,
it needs costly training and the trained model may not be applicable to data deviating too much from the training data. Using
Newton’s identities from the theory of symmetric polynomials, this paper presents a simple closed-form formula for computing
GDOP with the inputs used in previous studies. These inputs include traces of the measurement matrix and its second and third
powers, and the determinant of the matrix. 相似文献
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利用联邦滤波器设计SINS／RDSS／GPS组合导航系统 总被引：3，自引：0，他引：3
介绍了Garlson提出的分布式联邦滤波理论，讨论了两类系统设计类型和四种配置模式的特征。首次提出SINS／RDSS／GPS组合导航的设想，并对各子系统特点进行了探讨和对SINS／RDSS子系统进行了建模，建议在实际开发中采用NR配置模式，该模式属于A类联邦滤波系统。通过算例验证了NR模式融合结果的近似最优性、优良的容错性和故障探测能力。 相似文献
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地基GPS反演水汽影响因素分析 总被引：1，自引：1，他引：0
地基GPS(Global Position System)技术日益成熟,气象观测应用此技术逐渐增多,但对此影响因素的分析不是太多。本文首先阐述了地基GPS遥感水汽原理,然后结合雾灵山GPS气象观测试验数据,利用GAMIT软件解算此期间数据的对流层延迟量,主要分析了影响地基GPS遥感水汽的几项因素,得出测站精度与ZTD精度变化趋势图、星历精度与ZTD(Troposphere Zenith Delay)精度变化趋势图和不同参考站对ZTD的影响。其结果对GPS遥感大气水汽有一定的参考价值。 相似文献