scholarly journals Reference point determination with a new mathematical model at the 20 m VLBI radio telescope in Wettzell

2008 ◽  
Vol 2 (4) ◽  
Author(s):  
Michael Lösler
Keyword(s):  
Mathematical Model ◽  
Radio Telescope ◽  
Reference Point ◽  
Point Determination

scholarly journals ILRS Reference Point Determination Using Close Range Photogrammetry

2021 ◽  
Vol 11 (6) ◽  
pp. 2785
Author(s):  
Michael Lösler ◽  
Cornelia Eschelbach ◽  
Thomas Klügel ◽  
Stefan Riepl
Keyword(s):  
Reference Point ◽  
Reference Points ◽  
Geodetic Reference System ◽  
Unscented Transformation ◽  
Local Ties ◽  
Close Range Photogrammetry ◽  
Crucial Component ◽  
Space Geodetic Techniques ◽  
Close Range ◽  
Point Determination

A global geodetic reference system (GGRS) is realized by physical points on the Earth’s surface and is referred to as a global geodetic reference frame (GGRF). The GGRF is derived by combining several space geodetic techniques, and the reference points of these techniques are the physical points of such a realization. Due to the weak physical connection between the space geodetic techniques, so-called local ties are introduced to the combination procedure. A local tie is the spatial vector defined between the reference points of two space geodetic techniques. It is derivable by local measurements at multitechnique stations, which operate more than one space geodetic technique. Local ties are a crucial component within the intertechnique combination; therefore, erroneous or outdated vectors affect the global results. In order to reach the ambitious accuracy goal of 1 mm for a global position, the global geodetic observing system (GGOS) aims for strategies to improve local ties, and, thus, the reference point determination procedures. In this contribution, close range photogrammetry is applied for the first time to determine the reference point of a laser telescope used for satellite laser ranging (SLR) at Geodetic Observatory Wettzell (GOW). A measurement campaign using various configurations was performed at the Satellite Observing System Wettzell (SOS-W) to evaluate the achievable accuracy and the measurement effort. The bias of the estimates were studied using an unscented transformation. Biases occur if nonlinear functions are replaced and are solved by linear substitute problems. Moreover, the influence of the chosen stochastic model onto the estimates is studied by means of various dispersion matrices of the observations. It is shown that the resulting standard deviations are two to three times overestimated if stochastic dependencies are neglected.

scholarly journals Prospective study of high geodetic resolution to future VGOS reference point determination

2019 ◽  
Vol 10 (2) ◽  
pp. 163-171
Author(s):  
Zhibin Zhang ◽  
Guangli Wang ◽  
Dezhen Xu ◽  
Shize Song
Keyword(s):  
Prospective Study ◽  
Reference Point ◽  
Point Determination

scholarly journals An accurate fingerprint reference point determination method based on curvature estimation of separated ridges

2018 ◽  
Vol 28 (1) ◽  
pp. 209-225 ◽  
Author(s):  
Rafal Doroz ◽  
Krzysztof Wrobel ◽  
Piotr Porwik
Keyword(s):  
Reference Point ◽  
Reference Points ◽  
Second Step ◽  
Multi Stage ◽  
Stage System ◽  
Series Of Experiments ◽  
Curvature Estimation ◽  
Point Determination ◽  
Point Detection

AbstractThis paper presents an effective method for the detection of a fingerprint’s reference point by analyzing fingerprint ridges’ curvatures. The proposed approach is a multi-stage system. The first step extracts the fingerprint ridges from an image and transforms them into chains of discrete points. In the second step, the obtained chains of points are processed by a dedicated algorithm to detect corners and other points of highest curvature on their planar surface. In a series of experiments we demonstrate that the proposed method based on this algorithm allows effective determination of fingerprint reference points. Furthermore, the proposed method is relatively simple and achieves better results when compared with the approaches known from the literature. The reference point detection experiments were conducted using publicly available fingerprint databases FVC2000, FVC2002, FVC2004 and NIST

scholarly journals Research on Mathematical Model for Non-Uniformly Qualitative Suspension Cable

2018 ◽  
Vol 175 ◽  
pp. 03039
Author(s):  
Hu Yong ◽  
Du Yuxin ◽  
Cao Yong ◽  
Wang MaoSen ◽  
Ma Yuchi ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Perturbation Method ◽  
Radio Telescope ◽  
Theoretical Basis ◽  
Transcendental Function ◽  
Concentrated Loads ◽  
Real Situation ◽  
The Real ◽  
Suspension Cable ◽  
The Mathematical Model

Catenary theory is recognized as the most effective suspension theory which can reflect the real situation of suspension. Catenary equation belongs to transcendental function, so there are some difficulties in calculation and application. Parabola theory, suspension curve theory and perturbation method are gradually formed as the theoretical basis for the study of suspension cables. This paper takes the 500m spherical radio telescope project as the background. The modeling method of suspension cable under multiple concentrated loads is analyzed, and the mathematical model of supporting cable after load is derived. The research in this paper provides a reference for the establishment of mathematical model of suspension cable in practice.

Fingerprint Reference Point Determination Based on Orientation Features

2010 ◽  
Author(s):  
Shan Juan Xie ◽  
Sook Yoon ◽  
Hui Gong ◽  
Jinwook Shin ◽  
Dong Sun Park
Keyword(s):  
Reference Point ◽  
Point Determination

Geodetic Determination of Radio Telescope Antenna Reference Point and Rotation Axis Parameters

2007 ◽  
Vol 133 (2) ◽  
pp. 41-51 ◽  
Author(s):  
Stefan Leinen ◽  
Matthias Becker ◽  
John Dow ◽  
Joachim Feltens ◽  
Knud Sauermann
Keyword(s):  
Radio Telescope ◽  
Reference Point ◽  
Rotation Axis

scholarly journals A generalized meshing analysis method and its application to toroidal surface enveloping conical worm drive

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110630
Author(s):  
Chongfei Huai ◽  
Chunlin Chen ◽  
Yaping Zhao
Keyword(s):  
Mathematical Model ◽  
Reference Point ◽  
Unit Vector ◽  
Normal Vector ◽  
Analysis Method ◽  
Profile Angle ◽  
Toroidal Surface ◽  
Conical Worm ◽  
Worm Drive ◽  
Application Scope

A generalized method for the meshing analysis of conical worm drive is proposed, whose mathematical model is more general and whose application scope is expanded. A universal mathematical model, which can be conveniently applied to left-handed and right-handed conical worm pairs and their tooth flanks on different sides, is established by introducing the helical spin coefficient and tooth side coefficient of the conical worm. The pressure angle at the reference point, which is a key parameter for calculating the curvature parameters and lubrication angle, is determined based on the unit normal vector of the worm helical surface and is no longer determined by the tooth profile angle in the worm shaft section. The above improvement breaks away from the limitation of the classic meshing analysis method based on the reference-point-based meshing theory and thus expands its application scope. The toroidal surface enveloping conical worm drive is taken as an instance to illustrate the proposed method and the numerical example studies are conducted. The approaches to determine the reference point, the normal unit vector, and the curvature parameters at the reference point are all demonstrated in detail. The numerical results all manifest that the method presented in the current work is correct and practicable.

Sign in / Sign up

Export Citation Format

Share Document