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Geodesy and Geodynamics 2024年第1期15卷 13-26页

作者： Xianjie Li jean-pierre barriot Bernard Ducarme Marania Hopuare Yidong Lou Geodesy Observatory of Tahiti University of French PolynesiaFaa'a 98702French Polynesia Catholic University of Louvain Georges Lemaître Centre for Earth and Climate Research(ELI)1348 Louvain-la-NeuveBelgium GNSS Research Center Wuhan UniversityWuhan 430079China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China

In this study,we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System(GNSS)receivers over French Polynesia during the period 2007-2020,and obtain,as ancillary results,estimates of the absolute changes in sea level at the same *** verify our processing approach to determining vertical motion,we first modeled vertical motion at the International GNSS Service(IGS)THTI station located in the capital island of Tahiti and compared our estimate with previous independent determinations,with a good *** obtained the following estimates for the vertical land motions at the tide gauges:Tubuai island,Austral Archipelago-0.92±0.17 mm/yr,Vairao village,Tahiti Iti:-0.49±0.39 mm/yr,Rikitea,Gambier Archipelago-0.43±0.17 mm/*** absolute variations of the sea level are:Tubuai island,Austral Archipelago 5.25±0.60 mm/yr,Vairao village,Tahiti Iti:3.62±0.52 mm/yr,Rikitea,Gambier Archipelago 1.52±0.23 mm/*** discuss these absolute values in light of the values obtained from altimetric measurements and other means in French Polynesia.

关键词： GPS Tide gauges Sea level changes Vertical land motion

Reconstructing the cruise-phase trajectory of deep-space probes in a general relativistic framework:An application to the Cassini gravitational wave experiment

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Astrodynamics 2023年第3期7卷 301-314页

作者： Joseph O’Leary jean-pierre barriot School of Physics University of MelbourneParkvilleVIC3010Australia Australian Research Council Centre of Excellence for Gravitational Wave Discovery(OzGrav) ParkvilleVIC3010Australia Observatoire Géodésique de Tahiti University of French PolynesiaBP 657098702Faa’aTahitiFrench Polynesia

Einstein’s theory of general relativity is playing an increasingly important role in fields such as interplanetary navigation,astrometry,and *** spacecraft and interplanetary probe prediction and estimation platforms employ a perturbed Newtonian framework,supplemented with the Einstein-Infeld-Hoffmann n-body equations of *** time in Newtonian mechanics is formally universal,the accuracy of modern radiometric tracking systems necessitate linear corrections via increasingly complex and error-prone post-Newtonian techniques—to account for light deflection due to the solar system *** flagship projects such as the ESA/JAXA BepiColombo mission now operating at unprecedented levels of accuracy,we believe the standard corrected Newtonian paradigm is approaching its limits in terms of *** this paper,we employ a novel prototype software,General Relativistic Accelerometer-based Propagation Environment,to reconstruct the Cassini cruise-phase trajectory during its first gravitational wave experiment in a fully relativistic *** results presented herein agree with post-processed trajectory information obtained from NASA’s SPICE kernels at the order of centimetres.

关键词： general relativity planetary orbitography orbit prediction and determination

Combination of Tsoft and ET34-ANA-V80 software for the preprocessing and analysis of tide gauge data in French Polynesia

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Geodesy and Geodynamics 2023年第1期14卷 26-34页

作者： Bernard Ducarme jean-pierre barriot Fangzhao Zhang Catholic University of Louvain Georges Lemaître Centre for Earth and Climate Research(ELI)1348 Louvain-la-NeuveBelgium Geodesy Observatory of Tahiti University of French Polynesia(UPF)PunaauiaFrench Polynesia College of Geodesy and Geomatics Shandong University of Science and TechnologyQingdao 266590China

Since 2008 a network of five sea-level monitoring stations was progressively installed in French *** stations are autonomous and data,collected at a sampling rate of 1 or 2 min,are not only recorded locally,but also transferred in real time by a radio-link to the NOAA through the GOES *** new ET34-ANA-V80 version of ETERNA,initially developed for Earth Tides analysis,is now able to analyze ocean tides *** a two-step validation scheme,we took advantage of the flexibility of this new version,operated in conjunction with the preprocessing facilities of the Tsoft software,to recover co rrected data series able to model sea-level variations after elimination of the ocean tides *** performed the tidal analysis of the tide gauge data with the highest possible selectivity(optimal wave grouping)and a maximum of additional terms(shallow water constituents).Our goal was to provide corrected data series and modelled ocean tides signal to compute tide-free sea-level variations as well as tidal prediction models with centimeter *** also present in this study the characteristics of the ocean tides in French Polynesia and preliminary results concerning the non-tidal variations of the sea level concerning the tide gauge setting.

关键词： Tide gauges Tidal data processing Mean sea level

Strong Spatial Aggregation of Martian Surface Temperature Shaped by Spatial and Seasonal Variations in Meteorological and Environmental Factors

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Research in Astronomy and Astrophysics 2022年第1期22卷 156-173页

作者： Yao-Wen Luo Fei Li Jian-Guo Yan jean-pierre barriot Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan430070China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan430070China Observatoire Geodesique de Tahiti University of French PolynesiaBP 6570F-98702 Faa'aTahitiFrench Polynesia

Spatio-temporal variation in the Martian surface temperature(MST)is an indicator of ground level thermal processes and hence a building block for climate ***,the distribution of MST exhibits different levels of spatial aggregation or heterogeneity,and varies in space and ***,the effect of regional differences in meteorological or environmental factors on the MST is not well ***,we investigated the degree of spatial autocorrelation of MST across the surface of Mars globally by Moran’s I,and identified the hot spots by GetisOrd G;*.We also estimated the regional differences in the influence of seasonally dominant factors including thermal inertia(TI),albedo,surface pressure,latitude,dust and slope on MST by a geographically weighted regression *** results indicate(1)that MST is spatially aggregated and hot and cold spots varied over time and space.(2)Hemispheric differences in topography,surface TI and albedo were primarily responsible for the hemispheric asymmetry of hot spots.(3)The dominant factors varied by geographical locations and *** example,the seasonal Hadley circulation dominates at the low-latitudes and CO;circulation at the high-latitudes.(4)Regions with extreme variations in topography and low TI were sensitive to meteorological and environmental factors such as dust and CO_(2)*** conclude that the spatial autocorrelation of MST and the spatial and seasonal heterogeneity of influencing factors must be considered when simulating Martian climate *** work provides a reference for further exploration of Martian climatic processes.

关键词： methods:analytical planets and satellites:surfaces methods:statistical planets and satellites:fundamental parameters

Computation of the atmosphere-less light intensity curve during a total solar eclipse by using Lunar Reconnaissance Orbiter topography data and the DE430 astronomical ephemeris

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Research in Astronomy and Astrophysics 2021年第1期21卷 105-118页

作者： Yun-Bo Wang Jian-Guo Yan Mao Ye Yong-Zhang Yang Fei Li jean-pierre barriot State Key Laboratory of InformationEngineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Geodesy Observatory of Tahiti University of French PolynesiaBP 657098702 FaaTahitiFrench Polynesia Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

Observations of the sky irradiation intensity in the visible wavelengths during a solar eclipse permit to model the Sun diameter,a key number to constrain the internal structure of our *** this paper,we present an algorithm that takes advantage of the precise Moon topography from Lunar Reconnaissance Orbiter to compute,with a high resolution in time,the geometrical part(***-of-atmosphere,and for a given wavelength)of the sky irradiation at any given location on the Earth during these *** algorithm is also able to model the Baily’s *** give as an application the theoretical computation of the light curve corresponding to the solar eclipse observed at Lakeland(Queensland,North Australia)on 2012 November *** application to real data,with the introduction of atmospheric and instrumental passbands,will be considered in a forthcoming paper.

关键词： eclipse Moon Sun:fundamental parameters

Inversion of Venus internal structure based on geodetic data

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Research in Astronomy and Astrophysics 2020年第8期20卷 237-251页

作者： Chi Xiao Fei Li Jian-Guo Yan Wei-Feng Hao Yuji Harada Mao Ye jean-pierre barriot Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Space Science Institute Macao University of Science and TechnologyAvenida WailongTaipaMacaoChina Observatory Geodetic de Tahiti BP 657098702 Faa'aTahitiFrench Polynesia

Understanding the internal structure of Venus promotes the exploration of the evolutionary history of this ***,the existing research concerning the internal structure of Venus has not used any inversion *** this work we employed an inversion method to determine the internal structure of Venus using observational or hypothetical geodetic data;these data include mass,mean radius,mean moment of inertia and second degree tidal Love number *** determine the core state of Venus,we created two models of Venus,an isotropic 3-layer model with entire liquid core and an isotropic 4-layer model with liquid outer core and a solid inner core,assuming that the interior of Venus is spherically symmetric and in hydrostatic equilibrium.A series of the sensitivity analysis of interior structure parameters to the geodetic data considered in here shows that not all of the parameters can be constrained by the geodetic data from *** this basis,a Markov Chain Monte Carlo algorithm was used to determine the posterior probability distribution and the optimal values of the internal structure parameters of Venus with the geodetic *** found that the 3-layer model is more credible than the 4-layer model via currently geodetic *** the assumption of the 3-layer model with the k2=0.295±0.066,I/MR^2=0.33±0.0165,andρ=5242.7±2.6 kg m^-3,the liquid iron-rich core of Venus has a radius of 3294+215-261km,which suggests a larger core than previous research has *** average density of the mantle and liquid core of Venus are 4101+325-375and 11885+955-1242kg m~^-3,respectively.

关键词： planets and satellites:interiors planets and satellites:terrestrial planets planets and satellites:physical evolution planets and satellites:fundamental parameters

Monitoring Zenithal Total Delays over the three different climatic zones from IGS GPS final products:A comparison between the use of the VMF1 and GMF mapping functions

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Geodesy and Geodynamics 2019年第2期10卷 93-99页

作者： Benachour Labib Jianguo Yan jean-pierre barriot Fangzhao Zhang Peng Feng State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan University Geodesy Observatory of Tahiti University of French Polynesia

The International GNSS Service(IGS) final products(ephemeris and clocks-correction) have made the GNSS an indispensable low-cost tool for scientific research, for example sub-daily atmospheric water vapor monitoring. In this study, we investigate if there is a systematic difference coming from the choice between the Vienna Mapping Function 1(VMF1) and the Global Mapping Function(GMF) for the modeling of Zenith Total Delay(ZTD) estimates, as well as the Integrated Precipitable Water Vapor(IPWV) estimates that are deduced from them. As ZTD estimates cannot be fully separated from coordinate estimates, we also investigated the coordinate repeatability between subsequent *** this purpose, we monitored twelve GNSS stations on a global scale, for each of the three climatic zones(polar, mid-latitudes and tropical), with four stations on each zone. We used an automated processing based on the Bernese GNSS Software Version 5.2 by applying the Precise Point Positioning(PPP)approach, L3 Ionosphere-free linear combination, 7 cutoff elevation angle and 2 h sampling. We noticed an excellent agreement with the ZTD estimates and coordinate repeatability for all the stations w.r.t to CODE(the Center for Orbit Determination in Europe) and USNO(US Naval Observatory) products, except for the Antarctic station(Davis) which shows systematic biases for the GMF related results. As a final step, we investigated the effect of using two mapping functions(VMF1 and GMF) to estimate the IPWV,w.r.t the IPWV estimates provided by the Integrated Global Radiosonde Archive(IGRA). The GPS-derived IPWV estimates are very close to the radiosonde-derived IPWV estimates, except for one station in the tropics(Tahiti).

关键词： International GNSS Service (IGS) Vienna Mapping Function 1 (VMF1) Global Mapping Function (GMF) Precise Point Positioning (PPP) Zenith Total Delay (ZTD) Zenith Wet Delay (ZWD) Integrated Precipitable Water Vapor (IPWV)

Reducing loss of significance in the computation of Earth-based two-way Doppler observables for small body missions

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Research in Astronomy and Astrophysics 2021年第8期21卷 75-90页

作者： Wei-Tong Jin Fei Li Jian-Guo Yan Xuan Yang Mao Ye Wei-Feng Hao Thomas Paul Andert jean-pierre barriot State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang 050200China Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China Universitat der Bundeswehr München NeubibergBayern85579Germany University of French Polynesia BP 6570F-98702 Faa'aTahitiFrench Polynesia

Two-way Doppler measurement is a typical Earth-based radiometric technique for interplanetary spacecraft navigation and gravity science *** most widely used model for the computation of two-way Doppler observables is Moyer’s differenced-range Doppler(DRD) formula,which is based on a Schwarzschild approximation of the Solar-System ***,the computation of range difference in DRD formula is sensitive to round-off errors due to approximate numbers defined by the norm IEEE754 in all *** paper presented two updated models and their corresponding detailed instructions for the computation of the two-way Doppler observables so as to impair the effects of this type of numerical *** two models were validated by two case studies related to the Rosetta mission—asteroid Lutetia flyby and comet 67 P/Churyumov-Gerasimenko orbiting *** these two cases,the numerical noise from the updated models can be reduced by two orders-of-magnitude in the computed two-way Doppler *** results showed an accuracy from better than 6 × 10^(-3) mm s^(-1) at 1 s counting time interval to better than 3 × 10^(-5) mm s^(-1) at 60 s counting time interval.

关键词： methods:numerical space vehicles planets and satellites:general

A new method to determine the gravity field of small bodies from line-of-sight acceleration data

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Research in Astronomy and Astrophysics 2019年第3期19卷 155-164页

作者： Nian-Chuan Jian Jian-Guo Yan Jin-Song Ping jean-pierre barriot J.Alexis P.Rodriguez Shanghai Astronomical Observatory Chinese Academy of Science State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Instituto de Astronomia y Ciencias Planetarias de Atacama Universidad de Atacama National Astronomical Observatory of China Chinese Academy of Science University of French Polynesia Geodesy Observatory of Tahiti Laboratoire GEPASUD Planetary Science Institute

We present a new method to derive line-of-sight acceleration observables from spacecraft radio tracking data. The observables can be used to estimate the mass and gravity of a natural satellite as a spacecraft flyby. The corresponding observation model adapts to one-way and two/three-way tracking modes. As a test case for method validation and application, we estimated the mass and degree two gravity field for the Martian moon Phobos using simulated tracking data when the spacecraft Mars Express flew by Phobos on 2013 December 29. We have a few real tracking data during flyby and they will be used to confirm raw data simulation. The main purpose of this paper is to demonstrate the method of line-of-sight acceleration reduction from raw tracking data and the feasibility to estimate mass and gravity of a natural satellite using this type of observable. This novel method is potentially applicable to planet and asteroid gravity field studies combined with Doppler tracking data.

关键词： line of sight acceleration-Doppler-celestial mechanics

A simulation experiment on the GM estimation for Comet 133P/Elst-Pizarro

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Research in Astronomy and Astrophysics 2021年第1期21卷 158-164页

作者： Wu-Tong Gao Jian-Guo Yan Wei-Tong Jin Xuan Yang Chen Yang Mao Ye Fei Li jean-pierre barriot l State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China China Academy of Space Technology Beijing 100094China Geodesy Observatory of Tahiti University of French PolynesiaBP 657098702 FaaaTahitiFrench Polynesia

In China’s asteroid mission to be launched around 2025,(7968)133 P/Elst-Pizarro(hereafter 133 P)will be the second target,after a visit to asteroid(469219)Kamo’*** paper describes a simulation of precise orbit determination for the spacecraft around comet 133 P,as well as estimation of its gravitational parameter(GM)value and the solar radiation pressure coefficient Cr for the *** cometocentric distances of 200,150 and 100 km orbits are considered,as well as two tracking modes:exclusive two-way range-rate mode(Earth station to spacecraft)and combinations of two-way range-rate and local spacecraft onboard ranging to the *** to exclusive two-way range-rate,the introduction of local ranging observables improves the final GM uncertainties by up to one order of *** ephemeris error in the orbit of 133 P is also considered,and we show that,to obtain a reliable estimate of the GM for 133 P,this error cannot exceed a one km range.

关键词： celestial mechanics space vehicles comets:individual(133P/Elst-Pizarro) methods:statistical