scholarly journals Preliminary Analysis and Evaluation of BDS-3 RDSS Timing Performance

2022 ◽  
Vol 14 (2) ◽  
pp. 352
Author(s):  
Rui Guo ◽  
Dongxia Wang ◽  
Nan Xing ◽  
Zhijun Liu ◽  
Tianqiao Zhang ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Satellite System ◽  
Timing Accuracy ◽  
Analysis And Evaluation ◽  
Geo Satellite ◽  
The One ◽  
Satellite Service ◽  
First Time ◽  
Performance Timing ◽  
Better Than

Radio determination satellite service (RDSS) is one of the characteristic services of Beidou navigation satellite system (BDS), and also distinguishes with other GNSS systems. BDS-3 RDSS adopts new signals, which is compatible with BDS-2 RDSS signals in order to guarantee the services of old users. Moreover, the new signals also separate civil signals and military signals which are modulated on different carriers to improve their isolation and RDSS service performance. Timing is an important part of RDSS service, which has been widely used in the field of the power, transportation, marine and others. Therefore, the timing accuracy, availability and continuity is an important guarantee for RDSS service. This paper summarizes the principle of one-way and two-way timing, and provides the evaluation method of RDSS timing accuracy, availability and continuity. Based on BDS-3 RDSS signal measurements of system, the performance of one-way timing and two-way timing is analyzed and evaluated for the first time. The results show that: (1) the accuracy of one-way timing and two-way timing is better than 30 ns and 8 ns respectively, which are better than the official claimed accuracy; (2) the RMS of one-way timing accuracy is 5.45 ns, which is 20% smaller than BDS-2, and the availability and continuity are 100%; (3) the RMS of two-way timing accuracy is 3.59 ns, which is 34% smaller than one-way timing, and both of the availability and continuity are 100%; (4) the orbit maneuver of GEO satellite make the one-way timing has 7.68 h recovery, but has no affection on the two-way timing.

Hesiod's Myth of the five (or three or four) races

1998 ◽  
Vol 43 ◽  
pp. 104-127 ◽  
Author(s):  
Glenn W. Most
Keyword(s):  
World History ◽  
Literary Form ◽  
Greek Literature ◽  
Human History ◽  
Physical Deterioration ◽  
The Many ◽  
The One ◽  
Definition Of ◽  
First Time ◽  
Better Than

Few passages in Greek literature are as familiar, and as perplexing, as the story of the various races of men in Hesiod'sWorks and Days. On the one hand, thismythseems perfectly to fulfill Italo Calvino's definition of a classic: somehow we seem always already to know it even when we come upon it for the very first time. For the conception of a golden age, when life was easier and men were better than now, has become so basic a motif of western culture that it is familiar even to the many who have never read or even heard of theWorks and Days; moreover, Hesiod seems at first glance to deploy such widespread notions as those of a succession of ages of world history and of a steady moral and physical deterioration from the beginning of human history to the present. But on the other hand, the specific literary form which this myth assumes in thetextin which it is embodied here seems strangely at odds with these familiar ideas. For Hesiod's text has a richness and complexity far in excess of what would be needed to communicate them, and in certain crucial respects seems to be at variance or even in contradiction with them. Instead of simply distinguishing between past and present, Hesiod apparently constructs a complicated scheme juxtaposing four metals in descending order of value, from gold through silver and bronze to iron; but he then goes on to confuse this pattern by inserting between the bronze and iron races a race of heroes who not only are not associated with any metal but also interrupt the steady decline by being better than their immediate predecessors. Without Hesiod, we probably would not even have this myth; yet his own version of it seems oddly defective.

Evaluation of C-Band Precise Orbit Determination of Geostationary Earth Orbit Satellites based on the Chinese Area Positioning System

2013 ◽  
Vol 67 (2) ◽  
pp. 343-351 ◽  
Author(s):  
Cao Fen ◽  
Yang XuHai ◽  
Su MuDan ◽  
Li ZhiGang ◽  
Chen Liang ◽  
...  
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Earth Orbit ◽  
Positioning System ◽  
Time Service ◽  
Geostationary Earth Orbit ◽  
Precise Orbit ◽  
Geo Satellite ◽  
First Time ◽  
Better Than

Geostationary Earth Orbit (GEO) satellites play a significant role in the space segment of the Chinese Area Navigation System. The C-Band transfer ranging method developed by the National Time Service Center (NTSC) has been widely used in the Chinese Area Positioning System (CAPS), with its advantages of separating satellite ranging from time synchronization and being unaffected by weather. The explicit ranging correction models for the C-Band transfer ranging method are introduced in detail in this article for the first time. Precise Orbit Determination (POD) using C-Band pseudo-range observation of GEO satellite 2010-001A in July 2012 has been conducted. The residual Root Mean Square (RMS) of each site and POD are analysed with orbit difference over overlaps of adjacent orbit arcs. Moreover, the orbit of the GEO satellite has been evaluated by Satellite Laser Ranging (SLR) data from both domestic and foreign SLR sites for the first time. The residual RMS of POD using C-Band observation is better than 0·1 m, and the orbit difference over overlaps of adjacent orbit arcs is better than 3 m. In addition, the residual RMS in line-of-sight for a SLR site in China are better than 1 m, while the RMS for the Yarragadee site in Australia is about 3·4 m. It has been shown that the GEO satellite orbit accords very well with the C-Band observation. Also, the distribution of CAPS stations affects the orbit precision. All sites in CAPS are now located in China with low and medium latitudes. The residual RMS of the SLR site in the southern hemisphere is larger than that of the site in China.

scholarly journals Introduction to polar earth orbits (PEO) in the function of the satellite distress and safety systems (SDSS)

2020 ◽  
Vol 19 (1) ◽  
pp. 285
Author(s):  
Dimov Stojce Ilcev
Keyword(s):  
Communication Systems ◽  
Polar Region ◽  
Satellite System ◽  
Economic Study ◽  
Safety Communication ◽  
Geo Satellite ◽  
Mobile Satellite ◽  
Safety Systems ◽  
Earth Orbits ◽  
Satellite Service

<p align="LEFT">In this paper is described introduction of Polar Earth Orbits (PEO) in the function of the Satellite Distress and Safety Systems (SDSS) for all mobile applications. The results of a technical and economic study regarding the extension of the Inmarsat Geostationary Earth Orbit (GEO) satellite system to cover polar region are reviewed. In addition, also are examined the technical and practical aspects of providing an operational polar Mobile Satellite Service (MSS) for the provision of combined distress and safety communication solutions in conjunction with a commercial and defense communication systems for maritime, land and aeronautical applications. This study is considered several PEO satellite models and their probable costs for Search and Rescue (SAR) and determination MSS solutions. The practical usage of Low PEO constellation is realized by Cospas-Sarsat international project for SDSS.</p>

scholarly journals tfaw survey – I. Wavelet-based denoising of K2 light curves. Discovery and validation of two new Earth-sized planets in K2 campaign 1

2020 ◽  
Vol 498 (2) ◽  
pp. 2778-2797
Author(s):  
D del Ser ◽  
O Fors
Keyword(s):  
Detection Efficiency ◽  
Light Curves ◽  
Type Star ◽  
Posterior Distributions ◽  
Denoising Method ◽  
Low Snr ◽  
The One ◽  
Almost All ◽  
First Time ◽  
Better Than

ABSTRACT The wavelet-based detrending and denoising method tfaw is applied for the first time to EVEREST 2.0-corrected light curves to further improve the photometric precision of almost all K2 observing campaigns (C1–C8, C12–C18). The performance of both methods is evaluated in terms of 6 h combined differential photometric precision (CDPP), simulated transit detection efficiency, and planet characterization in different SNR regimes. On average, tfaw median 6 h CDPP is ${\sim} 30{\rm {per \, cent}}$ better than the one achieved by EVEREST 2.0 for all observing campaigns. Using the transit least-squares (tls) algorithm, we show that the transit detection efficiency for simulated Earth–Sun-like systems is ∼8.5× higher for tfaw-corrected light curves than that for EVEREST 2.0 ones. Using the light curves of two confirmed exoplanets, K2-44 b (high SNR) and K2-298 b (low SNR), we show that tfaw yields better Markov chain Monte Carlo posterior distributions, transit parameters compatible with the catalogued ones but with smaller uncertainties, and narrows the credibility intervals. We use the combination of tfaw’s improved photometric precision and tls enhancement of the signal detection efficiency for weak signals to search for new transit candidates in K2 observing campaign 1. We report the discovery of two new K2-C1 Earth-sized planets statistically validated, using the vespa software: EPIC 201170410.02, with a radius of 1.047$^{+0.276}_{-0.257}\mathrm{ R}_{\oplus }$ planet orbiting an M-type star, and EPIC 201757695.02, with a radius of 0.908$^{+0.059}_{-0.064}\mathrm{ R}_{\oplus }$ planet orbiting a K-type star. EPIC 201757695.02 is the 9th smallest planet ever discovered in K2-C1, and the 39th smallest in all K2 campaigns.

Subjective Time Preference and Willingness to Pay for an Energy-Saving Durable Good

2001 ◽  
Vol 32 (3) ◽  
pp. 133-141 ◽  
Author(s):  
Gerrit Antonides ◽  
Sophia R. Wunderink
Keyword(s):  
Willingness To Pay ◽  
Energy Saving ◽  
Subjective Time ◽  
Durable Good ◽  
Discount Function ◽  
Hyperbolic Discount ◽  
The One ◽  
Two Parameter ◽  
Difference Effect ◽  
Better Than

Summary: Different shapes of individual subjective discount functions were compared using real measures of willingness to accept future monetary outcomes in an experiment. The two-parameter hyperbolic discount function described the data better than three alternative one-parameter discount functions. However, the hyperbolic discount functions did not explain the common difference effect better than the classical discount function. Discount functions were also estimated from survey data of Dutch households who reported their willingness to postpone positive and negative amounts. Future positive amounts were discounted more than future negative amounts and smaller amounts were discounted more than larger amounts. Furthermore, younger people discounted more than older people. Finally, discount functions were used in explaining consumers' willingness to pay for an energy-saving durable good. In this case, the two-parameter discount model could not be estimated and the one-parameter models did not differ significantly in explaining the data.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

Designing Women

2018 ◽  
Author(s):  
J. E. Smyth
Keyword(s):  
Working Women ◽  
Costume Design ◽  
Creative Force ◽  
Women's Fashion ◽  
The One ◽  
Studio Era ◽  
Average Woman ◽  
Better Than

During the early 1940s, journalists observed that after years of men controlling women’s fashion, Hollywood had become “a fashion center in which women designers are getting to be a big power.” In a town where “the working girl is queen,” it was women who really knew how to dress working women. Edith Head’s name dominates Hollywood costume design. Though a relatively poor sketch artist who refused to sew in public, Head understood what the average woman wanted to wear and knew better than anyone how to craft her image as the-one-and-only Edith Head. However, she was one of many women who designed Hollywood glamour in the studio era. This chapter juxtaposes Head’s career with that of a younger, fiercely independent designer who would quickly upstage Head as a creative force. In many senses, Dorothy Jeakins’s postwar career ascent indicated the waning of the Hollywood system and the powerful relationship between female designers, stars, and fans.

scholarly journals Atlas of ticks (Acari: Argasidae, Ixodidae) in Germany

2021 ◽  
Author(s):  
Franz Rubel ◽  
Katharina Brugger ◽  
Lidia Chitimia-Dobler ◽  
Hans Dautel ◽  
Elisabeth Meyer-Kayser ◽  
...  
Keyword(s):  
Tick Species ◽  
Migratory Birds ◽  
Dermacentor Reticulatus ◽  
Ixodid Ticks ◽  
Federal States ◽  
Ixodes Frontalis ◽  
Argas Reflexus ◽  
The One ◽  
Argasid Tick ◽  
First Time

AbstractAn updated and increased compilation of georeferenced tick locations in Germany is presented here. This data collection extends the dataset published some years ago by another 1448 new tick locations, 900 locations of which were digitized from literature and 548 locations are published here for the first time. This means that a total of 3492 georeferenced tick locations is now available for Germany. The tick fauna of Germany includes two species of Argasidae in the genera Argas and Carios and 19 species of Ixodidae in the genera Dermacentor, Haemaphysalis, and Ixodes, altogether 21 tick species. In addition, three species of Ixodidae in the genera Hyalomma (each spring imported by migratory birds) and Rhipicephalus (occasionally imported by dogs returning from abroad with their owners) are included in the tick atlas. Of these, the georeferenced locations of 23 tick species are depicted in maps. The occurrence of the one remaining tick species, the recently described Ixodes inopinatus, is given at the level of the federal states. The most common and widespread tick species is Ixodes ricinus, with records in all 16 federal states. With the exception of Hamburg, Dermacentor reticulatus was also found in all federal states. The occurrence of the ixodid ticks Ixodes canisuga, Ixodes frontalis, Ixodes hexagonus and I. inopinatus were documented in at least 11 federal states each. The two mentioned argasid tick species were also documented in numerous federal states, the pigeon tick Argas reflexus in 11 and the bat tick Carios vespertilionis in seven federal states. The atlas of ticks in Germany and the underlying digital dataset in the supplement can be used to improve global tick maps or to study the effects of climate change and habitat alteration on the distribution of tick species.

scholarly journals NLOS Multipath Classification of GNSS Signal Correlation Output Using Machine Learning

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2503
Author(s):  
Taro Suzuki ◽  
Yoshiharu Amano
Keyword(s):  
Machine Learning ◽  
Satellite System ◽  
Training Data ◽  
Support Vector ◽  
Positioning Errors ◽  
Automated Method ◽  
Global Navigation Satellite ◽  
Better Than ◽  
Signal Correlation

This paper proposes a method for detecting non-line-of-sight (NLOS) multipath, which causes large positioning errors in a global navigation satellite system (GNSS). We use GNSS signal correlation output, which is the most primitive GNSS signal processing output, to detect NLOS multipath based on machine learning. The shape of the multi-correlator outputs is distorted due to the NLOS multipath. The features of the shape of the multi-correlator are used to discriminate the NLOS multipath. We implement two supervised learning methods, a support vector machine (SVM) and a neural network (NN), and compare their performance. In addition, we also propose an automated method of collecting training data for LOS and NLOS signals of machine learning. The evaluation of the proposed NLOS detection method in an urban environment confirmed that NN was better than SVM, and 97.7% of NLOS signals were correctly discriminated.

Sign in / Sign up

Export Citation Format

Share Document