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Journal of Ocean Engineering and Science 2021年第1期6卷 54-61页

作者： Alberto Boretti College of Engineering Prince Mohammad Bin Fahd UniversityAl KhobarSaudi Arabia

The absolute and relative rates of rise of the sea level are computed for the New York City area by coupling global positioning system records of the position of fixed domes nearby tide gauges,with the tide gauges’*** tide gauges are considered,one long-term trend,more reliable,The Battery,in lower Manhattan,and one shorter,less reliable,Sandy Hook,in New *** relative rates of rise of the sea level are+2.851 and+4.076 mm/*** subsidence rates are-2.151 and-3.076 mm/*** absolute rates of rise of the sea level are+0.7 and+1.0 mm/*** relative sea-level acceleration,reliable only in The Battery,is about+0.008 mm/yr².This acceleration is about the same as the world average long-term trend tide gauge,as well as the average long-term trend tide gauge of the East Coast of North *** absolute rate of rise of the sea level by 2050 in the lower Manhattan area will be likely less than 30 mm,and the absolute rate of rise of the sea level by 2100 likely less than 80 *** relative rate of rise of the sea level by 2050 in the Manhattan area will be likely 85 mm,and the relative rate of rise of the sea level by 2100 likely 228 mm,because of the overwhelming subsidence contribution.

关键词： Wetland Vertical Development Elevation Capital Thermo-Steric Sea-Level Rise Land Subsidence Tidal Marsh Sustainability global positioning system

Relativistic Effects in the global positioning system

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Journal of systems Engineering and Electronics 1995年第4期6卷 199-237页

作者： Neil Ashby (Department of Physics, University of Colorado, Boulder, Colorado 80309-0390 USA) Department of Physics University of Colorado Boulder Colorado 80309-0390 USA

The global positioning system (GPS) uses accurate atomic clocks in satellites and on the ground to provide world-wide position and time determination. These clocks have gravitational and motional frequency shifts which are so large that, without properly accounting for relativistic effects, the system would not work. As a practical matter, therefore, many individuals who use the GPS need to understand how relativistic effects accounted for in the system. This paper discusses relativistic effects arising from both special relativity and general relativity, and how these effects are incorporated in GPS operations. Two introductory sections on kinematics in special and general relativity, respectively, are followed by a section which describes how relativistic effects should be accounted for. The concept of synchroization in the Earth-Centered Inertial frame is discussed in detail. Numerical and experimental examples are given, showing the sizes of the various effects. The treatment of special and general relativity is sufficiently complete that a person should be able to follow the development without much reference to external material, except that a few standard results have been quoted from textbooks without derivation.

关键词： Relativity global positioning system Sagnac effect Synchronization.

A Noise Suppression Method in Attitude Measurement Using global positioning system

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A Noise Suppression Method in Attitude Measurement Using Glo...

Slip rate and interseismic coupling along the Moxi-Shimian segment of the Xianshuihe fault, Eastern Qinghai-Xizang Plateau

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作者： WANG Bo1,2,DENG Zhihong1,WANG Shunting1,FU Mengyin1 1.School of Automation,Beijing Institute of Technology,Beijing 100081,P.R.China2.School of Instrumentation Science and Opto-electronics Engineering,Beihang University,Beijing 100191,P.R.China

The noise in attitude measurement using global positioning system（GPS）influences the accuracy of the *** analyzing the relationship of errors,a noise suppression method using the total least squares is utilized for double difference carrier phase measurements and unit vectors between satellites and *** results indicate that compared to the traditional method,the accuracy of the attitude angles measurement is *** increased computation time of this method is also acceptable.

关键词： global positioning system Attitude Measurement Double Difference Noise Suppression

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Geodesy and Geodynamics 2024年第4期15卷 338-351页

作者： Xinyu Zhao Gang Liu Zhaosheng Nie Wei Xiong Wei Chen Mu Lin Dijin Wang Qi Li Jiansheng Yu Dongzhen Wang Pengfei Yu Institute of Seismology China Earthquake AdministrationWuhan 430071China Key Laboratory of Earthquake Geodesy.China Earthquake Administration Wuhan 430071China State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China

On September 5,2022,the Luding M6.8 earthquake occurred in the Moxi-Shimian segment of the Xianshuihe fault,coinciding with the historical ruptured zone of the 1786 Moxi *** seis-mogenic environment provides a foundation for comprehending the mechanism of the earthquake and its future *** the Moxi-Shimian segment,we establish a series of near-field global Navigation Satellite systems(GNsS)stations to enhance the spatial resolution of observational data for the inversion of the interseismic kinematic *** this study,with an elastic screw dislocation model con-strained by GNsS observations,the slip rate of the Moxi-Shimian segment is estimated to be 10.9±1.0 mm/yr,while the locking depth is 15.7±6.2 ***,we utilize a block-dislocation model to invert the interseismic fault coupling along the Kangding-Moxi-Shimian *** result indicates a gradual deepening of the locking depth along the section from Kangding to *** coseismic rupture of the 2022 event occurred within the high coupling regions in the Kangding-Moxi-Shimian segment,which indicates that the rupture kinematics in this event might be controlled by the interseismic *** seismic moment accumulated within the ruptured zone of the Luding earthquake since 1786 ranges in[1.42-3.40]×10^(19) N-m,which is significantly greater than the seismic moment released during the 2022 *** a result,we infer that the Luding earthquake released only a portion of the accumulated energy within the original rupture zone since 1786,indicating that the 2022 event has not caused a complete rupture in the Moxi-Shimian ***,there remains a substantial seismic hazard in this area.

关键词： Moxi-Shimian segment of Xianshuihe fault Luding earthquake global positioning system Interseismic kinematic parameters

Propagation modeling of ocean-scattered low-elevation GPS signals for maritime tropospheric duct inversion

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Chinese Physics B 2012年第10期21卷 600-613页

作者：张金鹏吴振森赵振维张玉生王波 School of Science Xidian University China Research Institute of Radio Wave Propagation Institute of Oceanographic Instrumentation

The maritime tropospheric duct is a low-altitude anomalous refractivity structure over the ocean surface,and it can significantly affect the performance of many shore-based/shipboard radar and communication *** propose the idea that maritime tropospheric ducts can be retrieved from ocean forward-scattered low-elevation global positioning system（GPS） *** is accomplished by matching the measured power patterns of the signals to those predicted by the forward propagation model as a function of the modified refractivity *** the basis of a parabolic equation method and bistatic radar equation,we develop such a forward model for computing the trapped propagation characteristics of an ocean forward-scattered GPS signal within a tropospheric duct.A new GPS scattering initial field is defined for this model to start the propagation modeling.A preliminary test on the performance of this model is conducted using measured data obtained from a 2009-experiment in the South China *** demonstrate that this model can predict GPS propagation characteristics within maritime tropospheric ducts and serve as a forward model for duct inversion.

关键词： global positioning system ocean surface scattering propagation modeling tropospheric duct inversion

Leveraged fault identification method for receiver autonomous integrity monitoring

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Chinese Journal of Aeronautics 2015年第4期28卷 1217-1225页

作者： Sun Yuan Zhang Jun Xue Rui School of Electronic and Information Engineering Beihang University

Receiver autonomous integrity monitoring（RAIM） provides integrity monitoring of global positioning system（GPS） for safety-of-life *** the process of RAIM, fault identification（FI） enables navigation to continue in the presence of fault *** by satellite geometry, the leverage of each measurement in position solution may differ ***, the conventional RAIM FI methods are generally based on maximum likelihood of ranging error for different measurements, thereby causing a major decrease in the probability of correct identification for the fault measurement with high *** this paper, the impact of leverage on the fault identification is *** leveraged RAIM fault identification（L-RAIM FI） method is proposed with consideration of the difference in leverage for each satellite in ***,the theoretical probability of correct identification is derived to evaluate the performance of L-RAIM FI *** experiments in various typical scenarios demonstrate the effectiveness of L-RAIM FI method over conventional FI methods in the probability of correct identification for the fault with high leverage.

关键词： Fault identification global positioning system Leverage Navigation systems Receiver autonomousintegrity monitoring

A two-step robust adaptive filtering algorithm for GNSS kinematic precise point positioning

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Chinese Journal of Aeronautics 2021年第10期34卷 210-219页

作者： Qieqie ZHANG Luodi ZHAO Long ZHAO School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China

In kinematic navigation and positioning,abnormal observations and kinematic model disturbances are one of the key factors affecting the stability and reliability of positioning ***,robust adaptive filtering algorithm is used to reduce the influence of them on positioning ***,it is difficult to accurately identify and separate the influence of abnormal observations and kinematic model disturbances on positioning results,especially in the application of kinematic Precise Point positioning(PPP).This has always been a key factor limiting the performance of conventional robust adaptive filtering *** address this problem,this paper proposes a two-step robust adaptive filtering algorithm,which includes two filtering steps:without considering the kinematic model information,the first step of filtering only detects the abnormal *** on the filtering results of the first step,the second step makes further detection on the kinematic model disturbances and conducts adaptive *** analysis and experiment results indicate that the two-step robust adaptive filtering algorithm can further enhance the robustness of the filtering against the influence of abnormal observations and kinematic model disturbances on the positioning ***,improvement of the stability and reliability of kinematic PPP is significant.

关键词： Classification factor adaptive filtering global positioning system Precise position holding Robust filtering Two-step filtering

Low C/N_0 Carrier Tracking Loop Based on Optimal Estimation Algorithm in GPS Software Receivers

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Chinese Journal of Aeronautics 2010年第1期23卷 109-116页

作者： Miao Jianfeng Chen Wu Sun Yongrong Liu Jianye Navigation Research Center College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016 China Department of Land Surveying and Geo-informatics Hong Kong Polytechnic UniversityHong Kong China

Suppressing jitter noises in a phase locked loop（ PLL） is of great importance in order to keep precise and continuous track of global positioning system （GPS）signals characterized by low carrier-to-noise ratio（ C/No ）. This article proposes and analyzes an improved Kalman-filter-based PLL to process weak carrier signals in GPS software receivers. After reviewing the optimal-bandwidth-based traditional second-order PLL, a Kalman-filter-based estimation algorithm is implemented for the new PLL by decorrelating the model error noises and the measurement noises. Finally,the efficiency of this new Kalman-filter-based PLL is verified by experimental data. Compared to the traditional second-order PLL, this new PLL is in position to make correct estimation of the carrier phase differences and Doppler shifts with less overshoots and noise disturbances and keeps an effective check on the disturbances out of jitter noises in PLL. The results show that during processing normal signals,this improved PLL reduces the standard deviation from 0. 010 69 cycle to 0. 007 63 cycle, and for weak signal processing,the phase jitter range and the Doppler shifts can be controlled within ± 17° and ±5 Hz as against ±25° and ＋ 15 Hz by the traditional PLL.

关键词： global positioning system signal processing Kalman filters software radio phase locked loop

Codes cross-correlation analysis and data/pilot code pairs optimization for Galileo E1 OS and GPS L1C

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Chinese Journal of Aeronautics 2013年第3期26卷 751-765页

作者： Yang Zaixiu Huang Zhigang Geng Shengqun School of Electronic and Information Engineering Beihang University

The Galileo E1 open service （OS） and the global positioning system （GPS） L1C are intending to use the multiplexed binary offset carrier （MBOC） modulation in E1/L1 band, including both pilot and data components. The impact of data and pilot codes cross-correlation on the distortion of the discriminator function （i.e., the S-curve） is investigated, when only the pilot （or data） components of MBOC signals are tracked. It is shown that the modulation schemes and the receiver configuration （e.g., the correlator spacing） strongly affect the S-curve bias. In this paper, two methods are proposed to optimize the data/pilot code pairs of Galileo E1 OS and GPS L1C. The optimization goal is to obtain the minimum average S-curve bias when tracking only the pilot components a the specific correlator spacing. Figures of merit, such as S-curve bias, correlation loss and code tracking variance have been adopted for analyzing and comparing the un-optimized and optimized code pairs. Simulation results show that the optimized data/pilot code pairs could significantly mitigate the intra-channel codes cross-correlation, and then improve the code tracking performance of MBOC signals.

关键词： Code cross-correlation Code pair optimization Galileo global positioning system Multiplexed binary offset carrier S-curve bias

Integrating BDS and GPS for precise relative orbit determination of LEO formation flying

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Chinese Journal of Aeronautics 2018年第10期31卷 2013-2022页

作者： Bin YI Defeng GU Xiao CHANG Kai SHAO College of Liberal Arts and Sciences National University of Defense Technology

Low-Earth-Orbit（LEO） formation-flying satellites have been widely applied in many kinds of space geodesy. Precise Relative Orbit Determination（PROD） is an essential prerequisite for the LEO formation-flying satellites to complete their mission in space. The contribution of the BeiDou Navigation Satellite system（BDS） to the accuracy and reliability of PROD of LEO formation-flying satellites based on a global positioning system（GPS） is studied using a simulation method. Firstly, when BDS is added to GPS, the mean number of visible satellites increases from9.71 to 21.58. Secondly, the results show that the 3-Dimensional（3 D） accuracy of PROD, based on BDS-only, GPS-only and BDS ＋ GPS, is 0.74 mm, 0.66 mm and 0.52 mm, respectively. When BDS co-works with GPS, the accuracy increases by 29.73%. Geostationary-Earth-Orbit（GEO） satellites and Inclined Geosynchronous-Orbit（IGSO） satellites are only distributed over the Asia-Pacific region; however, they could provide a global improvement to PROD. The difference in PROD results between the Asia-Pacific region and the non-Asia-Pacific region is not apparent. Furthermore, the value of the Ambiguity Dilution Of Precision（ADOP）, based on BDS ＋ GPS, decreases by 7.50% and 8.26%, respectively, compared with BDS-only and GPS-only. Finally, if the relative position between satellites is only a few kilometres, the effect of ephemeris errors on PROD could be ignored. However, for a several-hundred-kilometre separation of the LEO satellites, the SingleDifference（SD） ephemeris errors of GEO satellites would be on the order of centimetres. The experimental results show that when IGSO satellites and Medium-Earth-Orbit（MEO） satellites co-work with GEO satellites, the accuracy decreases by 17.02%.

关键词： Ambiguity Dilution Of Precision BeiDou Navigation Satellite system Geostationary-Earth-Orbit global positioning system LEO formation flying Precise Relative Orbit Determination