171 research outputs found
SnapperGPS: Collection of GNSS Signal Snapshots
No full textThis data collection contains digital global navigation satellite system (GNSS) signal snapshots and is accompanied by a repository with utilities to simplify working with the files, which you can find at https://github.com/JonasBchrt/snapshot-gnss-data.
We recorded the data in 2020 and 2021 using three of our SnapperGPS low-cost receivers, whose core components are an Echo 27 GPS L1 antenna and an SE4150L integrated GPS receiver circuit. Like most civilian low-cost GPS receivers, SnapperGPS operates in the L1 band with a centre frequency of 1.57542 GHz. However, Galileo's E1 signal, BeiDou's B1C signal, GPS' novel L1C signal, and SBAS' L1 signal have the identical centre frequency. So, we captured those signals, too. A SnapperGPS receiver down-mixes the incoming signal to a nominal intermediate frequency of 4.092 MHz, samples the resulting near-baseband signal at 4.092 MHz and digitises it with an amplitude resolution of one bit per sample. It considers only the in-phase component and discards the quadrature component.
The data collection consists of four static and seven dynamic tests under various conditions with 3700 GNSS signal snapshots in total.
We captured the 225 static snapshots on a hill top, on a bridge, in a courtyard, and in a park in 5-30 s intervals and the 3475 dynamic ones while cycling in either urban or rural environments and using 10 s intervals.
We obtained ground truth locations or tracks either by using an Ordnance Survey trig point, by employing satellite imagery from Google Maps or Google Earth, or with a Moto C smartphone with built-in GPS and A-GPS receiver.
While the trig point provides a ground-truth position with centimetre-level accuracy, the positions obtained from satellite imagery or with the Moto C are up to 5 m wrong with outliers up to 10 m.
The eleven datasets are stored in one folder per set named "A"-"K". Each snapshot is in a single binary ".bin" file with a name derived from the timestamp. One byte of the file holds the amplitude values of eight signal samples, i.e., the first byte holds the first eight samples. A zero bit represents a signal amplitude of +1 and a one bit a signal amplitude of -1. The order of the bits is 'little', i.e., reversed. For example, the byte 0b01100000 corresponds to the signal chunk [1 1 1 1 1 -1 -1 1]. In addition to the raw GNSS signal snapshots, you can find more data in a single "meta.json" file in each folder. The JSON struct in this file provides approximate latitude and longitude of the ground truth location of a static test in decimal degrees, an estimate of the true intermediate frequency in Hertz (the actual value differs from the nominal 4.092 MHz due to imprecisions of the hardware), all the file names of the binary files, the UTC timestamps of all files, and optionally temperature and pressure measurements from an on-board BMP280 sensor in degrees Celsius and pascal, respectively. Furthermore, a ".gpx" or ".kml" file holds the ground truth track for a dynamic test as nodes of a polyline. (Folder "I" contains two files that represent the first and the second part of the track, respectively.) Finally, each folder incorporates the broadcasted satellite navigation data from the respective day as RINEX 3.04 ".rnx" file downloaded from NASA's archive (https://cddis.nasa.gov/archive/gnss/data/daily/). The RINEX files allow to calculate, e.g., satellite orbits and clock corrections for all GNSS.
The datasets:
"A": 181 snapshots, static, hill top, ground truth from trig point, no temperatures & pressures
"B": 14 snapshots, static, bridge, ground truth from Google Maps, no temperatures & pressures
"C": 6 snapshots, static, courtyard, ground truth from Google Maps, no temperatures & pressures
"D": 24 snapshots, static, park, ground truth from Google Maps, incl. temperatures & pressures
"E": 380 snapshots, dynamic, urban, ground truth from Google Earth, incl. temperatures & pressures
"F": 339 snapshots, dynamic, urban, ground truth from Google Earth, incl. temperatures & pressures
"G": 693 snapshots, dynamic, urban/rural, ground truth from Google Earth, incl. temperatures & pressures
"H": 628 snapshots, dynamic, urban, ground truth from Moto C, incl. temperatures & pressures
"I": 1023 snapshots, dynamic, urban/rural, ground truth from Google Earth / Moto C, incl. temperatures & pressures
"J": 346 snapshots, dynamic, urban/rural, ground truth from Moto C, incl. temperatures & pressures
"K": 66 snapshots, dynamic, urban, ground truth from Moto C, incl. temperatures & pressure
Implications of the Warm Corona and Relativistic Reflection Models for the Soft Excess in Mrk 509
No full textWe present the analysis of the first Nuclear Spectroscopic Telescope Array observations (~220 ks), simultaneous with the last Suzaku observations (~50 ks), of the active galactic nucleus of the bright Seyfert 1 galaxy Mrk 509. The time-averaged spectrum in the 1–79 keV X-ray band is dominated by a power-law continuum (Γ ~ 1.8–1.9), a strong soft excess around 1 keV, and signatures of X-ray reflection in the form of Fe K emission (~6.4 keV), an Fe K absorption edge (~7.1 keV), and a Compton hump due to electron scattering (~20–30 keV). We show that these data can be described by two very different prescriptions for the soft excess: a warm (kT ~ 0.5–1 keV) and optically thick (τ ~ 10–20) Comptonizing corona or a relativistically blurred ionized reflection spectrum from the inner regions of the accretion disk. While these two scenarios cannot be distinguished based on their fit statistics, we argue that the parameters required by the warm corona model are physically incompatible with the conditions of standard coronae. Detailed photoionization calculations show that even in the most favorable conditions, the warm corona should produce strong absorption in the observed spectrum. On the other hand, while the relativistic reflection model provides a satisfactory description of the data, it also requires extreme parameters, such as maximum black hole spin, a very low and compact hot corona, and a very high density for the inner accretion disk. Deeper observations of this source are thus necessary to confirm the presence of relativistic reflection and further understand the nature of its soft excess
High Statistics Study of
No full textf , J. Ludemann b , H. Matthaey b , R. McCrady l , M. Merkel k 9 , J.P. Merlo k , C.A. Meyer l , L. Montanet f , A. Noble o 10 , F. Ould--Saada o K. Peters b , C.N. Pinder e , G. Pinter d , S. Ravndal b9 , C. Regenfus m , S. Resag c , R. Ruoured f , E. Schafer k , P. Schmidt g , R. Seibert g , S. Spanier o , H. Stock b , C. Straßburger c , U. Strohbusch g , M. Suffert n , U. Thoma c , M. Tischhauser h , D. Urner o , C. Volcker m , F. Walter k , D. Walther b , U. Wiedner g<F2
High-Statistics Study of
No full texta , R. Landua f , F. Loser g , J. Ludemann b , H. Matthay b , M. Merkel k10 , J.P. Merlo k , C.A. Meyer m , L. Montanet f , A. Noble o , F. Ould-Saada o , K. Peters b , C.N. Pinder e , G. Pinter d , S. Ravndal b10 , C. Regenfus l , J. Salk b , E. Schafer k , P. Schmidt g , R. Seibert g , S. Spanier k , H. Stock b , C. Straßburger c , U. Strohbusch g , M. Suffert n , U. Thoma c , D. Urner o , C. Volcker l , F. Walter k , D. Walther b , U. Wiedner g , N
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 15 September 1997
No full textThe decay ¯ pp (at rest)! K ffi L K \Sigma ß \Upsilon ß ffi , studied on a sample of more than 14000 events, is found to proceed dominantly via two-body channels containing resonances with open strangeness. Contributions from K 1 (1270) ¯ K and K 1 (1400) ¯ K , branching into the successive K 1 -decay modes, and from K ¯ K ; K ( ¯ Kß) S and (Kß) S ( ¯ Kß) S are extracted by means of a partial-wave analysis which accounts well for the data and also allows a search for weak contributions from other (Kßß) and from (K ¯ Kß) resonances. Striking asymmetries between the charged and the neutral kaonic resonances give evidence for interfering isospin 0 and 1 annihilation amplitudes. Kaonic annihilation channels of protonium have been a profitable source of meson spectroscopy since the early bubble chamber work [1]. The K ¯ Kßß channels give access to resonances in the open-strangeness (Kßß) and (Kß) and in the hidden-strangeness (K ¯ K) and (K ¯ Kß) systems. A peculi..
E Decays to ... in ... Annihilation At Rest
No full text19> , R. McCrady m , J.P. Merlo a , C.A. Meyer m , L. Montanet f , A. Noble o5 , R. Ouared f , F. Ould-Saada o , K. Peters b , C.N. Pinder e , G. Pinter d , S. Ravndal b , C. Regenfus l , E. Schafer k6 , P. Schmidt g , M. Schutrumpf b , I. Scott i , R. Seibert g , S. Spanier o , H. Stock b , C. Straßburger c , U. Strohbusch g , M. Suffert n , U. Thoma c , M. Tischhauser h , D. Urner o7 , C. Volcker l , F. Walter k , D. Walther b , U. Wiedner g , N. Winter h ,
Antiproton-Proton Annihilation At Rest Into
No full textThe annihilation channel ¯ pp ! K L K S ß 0 ß 0 was studied with the Crystal Barrel detector at LEAR. This final state with negative C-parity is dominated by the strange resonances K (892), K 1 (1270), K 1 (1400) and K 0 (1430). In addition, a J PC = 1 +\Gamma state is seen in the K K decay mode. This state could be the isoscalar, axialvector h 0 1 seen here with a mass of m = (1440 \Sigma 60) MeV=c 2 and a width of \Gamma = (170 \Sigma 80) MeV=c 2 . This is the first experimental study and partial wave analysis of the K L K S ß 0 ß 0 final state produced in ¯ pp annihilation at rest. The same final state has previously been indirectly identified in the reaction ¯ pp!K S M by Astier et al. [1], where M represents the missing neutral particle system K L ß 0 ß 0 . With three missing particles, no partial wave analysis could be performed. However, an amplitude analysis of the related reaction ¯ pp!K S K S ß + ß \Gamma was possible and was found to be ..
P- versus S-wave
No full text.02> m , U. Meyer-Berkhout h , L. Montanet c , A. Noble m , K. Peters a , G. Pinter b , S. Ravndal a , A.H. Sanjari i , E. Schafer g , B. Schmid m , P. Schmidt d , S. Spanier g , C. Straßburger g , U. Strohbusch d , M. Suffert k , D. Urner m , C. Volcker h , D. Walther a , U. Wiedner d , N. Winter e , J. Zoll c , C. Zupancic h a Universitat Bochum, D-4630 Bochum, FRG b Academy of Science, H-1525 Budapest, Hungary c CERN, CH-1211 Gen`eve, Switzerland d Universitat Hamburg, D-2000 Hamburg, FRG e Universitat Karlsruhe, W-7500 K
Pp-Annihilation Into
No full text. The annihilation channels pp!! 0 , !j, !j 0 were studied with the Crystal Barrel detector at LEAR at p-momenta of 600, 1200, and 1940 MeV=c. In most cases angular distributions were measured which allowed a complete J P -analysis using the helicity formalism. The contribution of all relevant initial states could be determined. The maximal contributing angular momenta are dependent on the p-momentum and range up to J = 5. 1 Introduction This paper reports on the measurement of selected twobody pp-annihilation channels performed with the Crystal Barrel (CB) detector at LEAR at p-momenta of 600, 1200 and 1940 MeV=c. The aims of the measurements were 2-fold: (1) Determine the angular momenta in the pp-system, which contribute to the annihilation process with increasing p-momenta. This information is vital for the analysis of 3-or more body annihilation pro- ? This work is part of the PhD. thesis of K. Beuchert ?? Now at University of Freiburg, Freiburg,Germany ??? Universi..
Pp Annihilation At Rest Into
No full textMatthay b , M. Merkel j 9 , J.P. Merlo j , C.A. Meyer l , L. Montanet e , A. Noble n , F. Ould-Saada n , K. Peters b , C.N. Pinder d , G. Pinter c , S. Ravndal b10 , J. Salk b , A.H. Sanjari h 11 , E. Schafer j , B. Schmid n 12 , P. Schmidt f , S. Spanier j , C. Straßburger j 13 , U. Strohbusch f , M. Suffert m , D. Urner n , C.Volker k , F. Walter f , D. Walther b , U. Wiedner f , N. Winter g , J. Zoll e , B.S. Zou h , C. Zupancic k a University of Cal
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