scholarly journals A LIBRATION MODEL FOR ENCELADUS BASED ON GEODETIC CONTROL POINT NETWORK ANALYSIS

Author(s):  
I. E. Nadezhdina ◽  
A. E. Zubarev ◽  
E. S. Brusnikin ◽  
J. Oberst

A new global control point network was derived for Enceladus, based on Cassini and Voyager-2 image data. Cassini images were taken from 2005 to 2014, for Voyager we have only one flyby in the middle of 1981. We have derived 3D Cartesian coordinates for 1128 control points as well as improved pointing data for 12 Voyager and 193 Cassini images in the Enceladus-fixed coordinate system. The point accuracies vary from 55 m to 2900 m (average point accuracy – 221 m). From tracking of the control points we detect a librational motion described by a model which includes 3 different periods and amplitudes (Rambaux et al., 2011). We determine the amplitudes for each term. Our new control point network has a higher number of point measurements and a higher accuracy than previous data (Giese et al., 2014).

Author(s):  
I. E. Nadezhdina ◽  
A. E. Zubarev ◽  
E. S. Brusnikin ◽  
J. Oberst

A new global control point network was derived for Enceladus, based on Cassini and Voyager-2 image data. Cassini images were taken from 2005 to 2014, for Voyager we have only one flyby in the middle of 1981. We have derived 3D Cartesian coordinates for 1128 control points as well as improved pointing data for 12 Voyager and 193 Cassini images in the Enceladus-fixed coordinate system. The point accuracies vary from 55 m to 2900 m (average point accuracy – 221 m). From tracking of the control points we detect a librational motion described by a model which includes 3 different periods and amplitudes (Rambaux et al., 2011). We determine the amplitudes for each term. Our new control point network has a higher number of point measurements and a higher accuracy than previous data (Giese et al., 2014).


Author(s):  
K. Di ◽  
B. Liu ◽  
M. Peng ◽  
X. Xin ◽  
M. Jia ◽  
...  

A lunar global control network provides geodetic datum and control points for mapping of the lunar surface. The widely used Unified Lunar Control Network 2005 (ULCN2005) was built based on a combined photogrammetric solution of Clementine images acquired in 1994 and earlier photographic data. In this research, we propose an initiative for construction of a new-generation lunar global control network using multi-mission data newly acquired in the 21<sup>st</sup> century, which have much better resolution and precision than the old data acquired in the last century. The new control network will be based on a combined photogrammetric solution of an extended global image and laser altimetry network. The five lunar laser ranging retro-reflectors, which can be identified in LROC NAC images and have cm level 3D position accuracy, will be used as absolute control points in the least squares photogrammetric adjustment. Recently, a new radio total phase ranging method has been developed and used for high-precision positioning of Chang’e-3 lander; this shall offer a new absolute control point. Systematic methods and key techniques will be developed or enhanced, including rigorous and generic geometric modeling of orbital images, multi-scale feature extraction and matching among heterogeneous multi-mission remote sensing data, optimal selection of images at areas of multiple image coverages, and large-scale adjustment computation, etc. Based on the high-resolution new datasets and developed new techniques, the new generation of global control network is expected to have much higher accuracy and point density than the ULCN2005.


A national geodetic network provides the fundamental framework that enables attainment of high accuracy geodetic measurements. It plays a key role in the efficiency and reliability of operations in land surveying, mapping, remote sensing, Geographic Information System, engineering surveying and other related applications. The geodetic framework provides the basis for integrating all mapping and survey activities. About eighty per cent of the primary geodetic control points in Kenya, established in the early twentieth century, have been destroyed. This has resulted in expensive and time consuming operations and processes for geospatial professionals and scientists. This situation is particularly worse in central Kenya, hence the need to extend the geodetic control by establishing more control points on secure and accessible sites for use by geospatial professionals and scientists in a wide variety of applications. In this study, modern satellite positioning techniques were utilised to extend geodetic reference network in central Kenya. Existing geodetic control points were used to facilitate establishment of new geodetic control points distributed within the region. Field observations were carried out using Global Positioning System. The raw data were downloaded, edited, processed and adjusted using Leica Geo-Office software. The resulting final adjusted coordinates had a maximum standard deviation of 2cm and 5cm on horizontal and vertical coordinates respectively, and a general loop misclosure of less than one part per million. The results showed that the quality of established control point positions was high, and demonstrated the efficient extension of geodetic control network using modern satellite positioning systems and efficient computational techniques in situations such as the ones currently prevailing in central Kenya.


2018 ◽  
Vol 20 (2) ◽  
pp. 81-89
Author(s):  
Eko Nugroho Julianto ◽  
Ispen Safrel ◽  
Arie Taveriyanto

Abstract. The quality of the coordinates of the points in a generally horizontal control network will be influenced by many factors, such as the system equipment used for measuring / observation, the network geometry, measurement strategies / observation, as well as data processing strategy implemented. Using development of the GPS satellite system, since 1989, the network provision of horizontal control points in Indonesia generally relies on the GPS satellite observations. One way of measuring geodetic control points with high accuracy is using geodetic GPS. Measurement of geodetic control points required as a control in the execution of the work and as a correction coordinate measurement of the position of a measurement object with a high degree of accuracy (± 1 cm). How many measurement methods that can be done. This research conducted measurement using static method. Static surveys are used to determine the coordinates of the control points are relatively distant from each other as well as order accuracy requires relatively higher. The measurement results obtained coordinate data for point 1 is 6 ° 57 '31.92207 "LS; 109 ° 38 '32.25194 "BT; high (ellipsoid) 34 320 m and point 2 is 6 ° 57 '33.59086 "LS; 109 ° 38 '37.87710 "BT; high (ellipsoid) 36 235 m.


2021 ◽  
Author(s):  
Elke Kersten ◽  
Anatoly E. Zubarev ◽  
Thomas Roatsch ◽  
Klaus-Dieter Matz

&lt;p&gt;Abstract&lt;/p&gt; &lt;p&gt;In preparation of the JUICE mission with the primary target Ganymede [1] we generated a new controlled version of the global Ganymede image mosaic using a combination of Voyager 1 and 2 and Galileo images. Baseline for this work was the new 3D control point network from Zubarev et al., 2016 [2], which uses the best available images from both missions and led to new position and pointing of the images.&lt;/p&gt; &lt;ul&gt; &lt;li&gt;Introduction&lt;/li&gt; &lt;/ul&gt; &lt;p&gt;Voyager 1 and Voyager 2 encountered Jupiter in 1979. They took 490 Narrow Angle Camera (NAC) and Wide Angle Camera (WAC) images of Ganymede&amp;#8217;s surface with pixel scales from 470 m/pxl down to 20 km/pxl. Galileo entered orbit around Jupiter in 1995 and flew by Ganymede 15 times to acquire 149 images (&lt;20 km/pxl). The new control point network of Ganymede led to higher geodetic accuracy in the data and thus created the incentive to generate a new basemap with a resolution &lt;1 km/pxl.&lt;/p&gt; &lt;ul&gt; &lt;li&gt;Image data&lt;/li&gt; &lt;/ul&gt; &lt;p&gt;The Voyager and Galileo images were acquired under very differing illumination and viewing conditions and from different observation times, although they have been taken within a short period each. Together with the varying flyby altitudes it strongly influences the images&amp;#8217; brightness, contrast, and resolution. Another fact is that images of Ganymede are limited, so there is barely an area covered twice with a proper resolution whereas the poles suffer from a lack of image data. To reach the highest possible coverage in the global mosaic, we selected 118 Voyager 1 and 2 images and 88 Galileo SSI images including high-resolution images (&lt;500 m/pxl) from three close Ganymede encounters [3].&lt;/p&gt; &lt;p&gt;&lt;strong&gt;&amp;#160;&lt;/strong&gt;&lt;/p&gt; &lt;ul&gt; &lt;li&gt;Control&lt;/li&gt; &lt;/ul&gt; &lt;p&gt;The 3D control point network was developed by the use of reconstructed spacecraft ephemerides [4] and consist of 3377 control points from 213 Voyager and Galileo images. The reprojection error is about 0.01-0.1 pixel and the coordinate accuracy of 78% of the control points is better than 5.0 km.&lt;/p&gt; &lt;ul&gt; &lt;li&gt;Mosaicking&lt;/li&gt; &lt;/ul&gt; &lt;p&gt;The selected images were reprocessed with the new pointing and orientation data and then reprojected into the final cylindrical equidistant projection, where the small crater Anat defines the longitude system at 232&amp;#176; East. After artefact correction, images with similar observation times and resolutions were set together to regional mosaics. The most work-intense part was the brightness and contrast correction of the regional mosaics and the remaining single images by tone-matching at the transition zones. The global Ganymede mosaic can be downloaded at https://janus.dlr.de/ and is archived at PSA: DOI &amp;#8211; 10.5270/esa-mqhvfjf.&lt;/p&gt; &lt;ul&gt; &lt;li&gt;Outlook&lt;/li&gt; &lt;/ul&gt; &lt;p&gt;The new Ganymede basemap with a global map scale of 359 m/pxl including some high-resolution images from Galileo increases the variety of available data products and should help during pre-JUICE arrival investigations of Ganymede and support the planning process.&lt;/p&gt; &lt;p&gt;References&lt;/p&gt; &lt;p&gt;[1] Grasset et al., 2013, Planetary and Space Science, 78, 1-21, DOI: 10.1016/S0032063312003777. [2] Zubarev et al., 2016, Solar System Research, 50, 5, 352-360, DOI: 10.1134/S0038094616050087. [3] Kersten et al., 2021, resubmitted to Planetary and Space Science. [4] Zubarev et al., 2015, Planetary and Space Science, 117, 246-249, DOI: 10.1016/S0032063315002007.&lt;/p&gt;


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jianying Yuan ◽  
Qiong Wang ◽  
Xiaoliang Jiang ◽  
Bailin Li

The multiview 3D data registration precision will decrease with the increasing number of registrations when measuring a large scale object using structured light scanning. In this paper, we propose a high-precision registration method based on multiple view geometry theory in order to solve this problem. First, a multiview network is constructed during the scanning process. The bundle adjustment method from digital close range photogrammetry is used to optimize the multiview network to obtain high-precision global control points. After that, the 3D data under each local coordinate of each scan are registered with the global control points. The method overcomes the error accumulation in the traditional registration process and reduces the time consumption of the following 3D data global optimization. The multiview 3D scan registration precision and efficiency are increased. Experiments verify the effectiveness of the proposed algorithm.


Author(s):  
T. Hu ◽  
J. Fan ◽  
H. He ◽  
L. Qin ◽  
G. Li

To address the difficulty involved when using existing commercial Geographic Information System platforms to integrate multi-source image data fusion, this research proposes the loading of multi-source local tile data based on CesiumJS and examines the tile data organization mechanisms and spatial reference differences of the CesiumJS platform, as well as various tile data sources, such as Google maps, Map World, and Bing maps. Two types of tile data loading schemes have been designed for the mashup of tiles, the single data source loading scheme and the multi-data source loading scheme. The multi-sources of digital map tiles used in this paper cover two different but mainstream spatial references, the WGS84 coordinate system and the Web Mercator coordinate system. According to the experimental results, the single data source loading scheme and the multi-data source loading scheme with the same spatial coordinate system showed favorable visualization effects; however, the multi-data source loading scheme was prone to lead to tile image deformation when loading multi-source tile data with different spatial references. The resulting method provides a low cost and highly flexible solution for small and medium-scale GIS programs and has a certain potential for practical application values. The problem of deformation during the transition of different spatial references is an important topic for further research.


2020 ◽  
Vol 206 ◽  
pp. 03025
Author(s):  
Junze Wang ◽  
Maohua Yao ◽  
Wenting Zhou ◽  
Xiangping Chen

In this paper, 24 C-level control points under different terrain conditions were selected to be the testing points. The binary-satellite system (GPS+GLONASS) and the triple-satellite system with BeiDou Navigation Satellite System (BDS) (BDS+GPS+GLONASS) were adopted for static measurement; and the observation data from BeiDou Ground-based Augumentation System (GBAS) base stations in Guangxi were collected for solution. By comparing the residuals of GPS tri-dimensional baseline vectors and the internal accord accuracy of each control point under the binary and triple-satellite systems, the effect of data collected by different satellite systems under different terrain conditions on measurement accuracy was studied. According to the results, (1) the triple-satellite system with BDS showed more stable measurement accuracy; (2) in plane, the two systems were of equivalent measurement accuracy in mountainous and flat areas; in elevation, the triple-satellite system showed higher and more stable measurement accuracy.


Author(s):  
H.K Lee ◽  
S.H. Yun ◽  
J.H. Kwon ◽  
J.S. Lee

The unified control points (UCPs), the multi-dimensional geodetic reference points installed in the low elevated area, has been established in Korea for the combination of the horizontal and the vertical geodetic control. While the 1st-phase UCPs network was completed in 2011 with a spatial density of about 10km, its densification has been underway as the 2nd-phase project. The UCPs supersedes the legacy geodetic points, such as triangulation points and benchmarks (BMs) once the 2nd-phase implementation. Although the horizontal network of the UPCs can be readily realised by GNSS technology, a technical challenge of the vertical component remains to be settled due to characteristics of the geodetic levelling technique. To this end, a pilot study was conducted to design a new version of the UCPs-based levelling network and to demonstrate its effectiveness with a comparison of the legacy. In this paper, a concept of the UCPs-based levelling network is briefly addressed with some prominent examples, and details of a pilot network and its measurements is given with the network adjustment procedure. Finally, results of the adjustments are provided with an emphasis on the influence of the newly designed network in terms of accuracy, reliability and estimated heights.


Fractals ◽  
2010 ◽  
Vol 18 (03) ◽  
pp. 271-286 ◽  
Author(s):  
HOUSSAM HNAIDI ◽  
ERIC GUÉRIN ◽  
SAMIR AKKOUCHE

This paper presents two self-similar models that allow the control of curves and surfaces. The first model is based on IFS (Iterated Function Systems) theory and the second on subdivision curve and surface theory. Both of these methods employ the detail concept as in the wavelet transform, and allow the multiresolution control of objects with control points at any resolution level.In the first model, the detail is inserted independently of control points, requiring it to be rotated when applying deformations. In contrast, the second method describes details relative to control points, allowing free control point deformations.Modeling examples of curves and surfaces are presented, showing manipulation facilities of the models.


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