scholarly journals Prediction of BeiDou Satellite Orbit Maneuvers to Improve the Reliability of Real-Time Navigation Products

2021 ◽  
Vol 13 (4) ◽  
pp. 629
Author(s):  
Zhiwei Qin ◽  
Le Wang ◽  
Guanwen Huang ◽  
Qin Zhang ◽  
Xingyuan Yan ◽  
...  
Keyword(s):  
Real Time ◽  
High Precision ◽  
Satellite Orbit ◽  
Satellite System ◽  
Service Performance ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Time Service ◽  
Beidou Satellites ◽  
Global Navigation Satellite

The positioning, navigation, and timing (PNT) service of the Global Navigation Satellite System (GNSS) is developing in the direction of real time and high precision. However, there are some problems that restrict the development of real-time and high-precision PNT technology. Satellite orbit maneuvering is one of the factors that reduce the reliability of real-time navigation products, especially the high-frequency orbit maneuvering of geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites. The BeiDou Navigation Satellite System (BDS) constellation is designed to contain GEO, IGSO, and medium earth orbit (MEO). These orbit maneuvers bring certain difficulties for data processing, especially for BeiDou satellites, such as decreased real-time service performance, which results in real-time navigation products including unusable maneuvered satellites. Additionally, the performance of real-time navigation products will decrease because the orbit maneuvers could not be known in advance, which diminishes the real-time PNT service performance of BDS for users. Common users cannot obtain maneuvering times and strategies owing to confidentiality, which can lead to a decline in the BDS real-time service performance. Thus, we propose a method to predict orbit maneuvers. BDS data from the broadcast ephemeris were analyzed to verify the availability of the proposed method. In addition, the results of real-time positioning were analyzed by using ultra-rapid orbit products, demonstrating that their reliability is improved by removing maneuvered satellites in advance. This is vital to improve the reliability of real-time navigation products and BDS service performance.

scholarly journals BeiDou Satellites Assistant Determination by Receiving Other GNSS Downlink Signals

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Lei Chen ◽  
Ke Zhang ◽  
Xiangwei Zhu ◽  
Yangbo Huang ◽  
Gang Ou ◽  
...  
Keyword(s):  
Doppler Frequency ◽  
Satellite Orbit ◽  
Cost Effective ◽  
Satellite System ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Ground Station ◽  
Minimum Number ◽  
Beidou Satellites ◽  
Global Navigation Satellite

GNSS’s orbit determinations always rely on ground station or intersatellite links (ISL). In the emergency of satellite-to-ground links and ISL break-off, BeiDou navigation satellite system (BDS) satellites cannot determine their orbits. In this paper, we propose to add a spaceborne annular beam antenna for receiving the global positioning system (GPS) and global navigation satellite system (GLONASS) signals; therefore, the BDS satellites may be capable of determining their orbits by GPS/GLONASS signals. Firstly, the spectrum selection, the power isolation, the range of Doppler frequency shift, and changing rate are taken into account for the feasibility. Specifically, the L2 band signals are chosen for receiving and processing in order to prevent the overlapping of the receiving and transmitting signals. Secondly, the minimum number of visible satellites (MNVS), carrier-to-noise ratio (C/N0), dilution of precision (GDOP), and geometric distance root-mean-square (gdrms) are evaluated for acquiring the effective receiving antennas’ coverage ranges. Finally, the scheme of deploying 3 receiving antennas is proved to be optimal by analysis and simulations over the middle earth orbit (MEO), geostationary earth orbit (GEO), and the inclined geosynchronous satellite orbit (IGSO). The antennas’ structures and patterns are designed to draw a conclusion that installing GPS and GLONASS receivers on BDS satellites for emergent orbits determination is cost-effective.

scholarly journals Real-Time Precise Point Positioning Using Orbit and Clock Corrections as Quasi-Observations for Improved Detection of Faults

2018 ◽  
Vol 71 (4) ◽  
pp. 769-787 ◽  
Author(s):  
Ahmed El-Mowafy
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Exclusion Process ◽  
Satellite Orbit ◽  
Satellite System ◽  
Navigation Satellite ◽  
System Service ◽  
Point Positioning ◽  
Predicted Values ◽  
Global Navigation Satellite

Real-time Precise Point Positioning (PPP) relies on the use of accurate satellite orbit and clock corrections. If these corrections contain large errors or faults, either from the system or by meaconing, they will adversely affect positioning. Therefore, such faults have to be detected and excluded. In traditional PPP, measurements that have faulty corrections are typically excluded as they are merged together. In this contribution, a new PPP model that encompasses the orbit and clock corrections as quasi-observations is presented such that they undergo the fault detection and exclusion process separate from the observations. This enables the use of measurements that have faulty corrections along with predicted values of these corrections in place of the excluded ones. Moreover, the proposed approach allows for inclusion of the complete stochastic information of the corrections. To facilitate modelling of the orbit and clock corrections as quasi-observations, International Global Navigation Satellite System Service (IGS) real-time corrections were characterised over a six-month period. The proposed method is validated and its benefits are demonstrated at two sites using three days of data.

scholarly journals Real-time integrity monitoring for a wide area precise positioning system

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Yuechen Wang ◽  
Jun Shen
Keyword(s):  
Real Time ◽  
High Precision ◽  
Satellite Orbit ◽  
Satellite System ◽  
Wide Area ◽  
Positioning System ◽  
Dual Frequency ◽  
Integrity Monitoring ◽  
Precise Positioning ◽  
Global Navigation Satellite

Abstract The wide area precise positioning system (WAPPS) is a high-precision positioning system based on a global navigation satellite system. Using a GEO satellite or a communication network, it provides users, in its service area, with real-time satellite orbit, clock, and other corrections. Users can achieve centimeter-level static positioning or decimeter-level kinematic positioning by precise point positioning. With the demands for applications of both high-precision and safety of life in real time, WAPPS is facing urgent needs to improve its service integrity. This study presents a real-time integrity monitoring approach for WAPPS. Using dual-frequency ionosphere-free corrections of GPS and BDS, along with monitor station data, related error models are established and the integrity monitoring is achieved, based on the analysis of satellite corrected residuals. In addition, satellite faults are simulated for performance verification. The results show that the algorithm can monitor both step and drift faults effectively and alert users in time.

scholarly journals Estimation of fractional cycle bias for GPS/BDS-2/Galileo based on international GNSS monitoring and assessment system observations using the uncombined PPP model

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jin Wang ◽  
Qin Zhang ◽  
Guanwen Huang
Keyword(s):  
Estimation Method ◽  
Satellite Orbit ◽  
Satellite System ◽  
Assessment System ◽  
Navigation Satellite ◽  
Dual Frequency ◽  
Fractional Cycle Bias ◽  
The Stability ◽  
High Consistency ◽  
Global Navigation Satellite

AbstractThe Fractional Cycle Bias (FCB) product is crucial for the Ambiguity Resolution (AR) in Precise Point Positioning (PPP). Different from the traditional method using the ionospheric-free ambiguity which is formed by the Wide Lane (WL) and Narrow Lane (NL) combinations, the uncombined PPP model is flexible and effective to generate the FCB products. This study presents the FCB estimation method based on the multi-Global Navigation Satellite System (GNSS) precise satellite orbit and clock corrections from the international GNSS Monitoring and Assessment System (iGMAS) observations using the uncombined PPP model. The dual-frequency raw ambiguities are combined by the integer coefficients (4,− 3) and (1,− 1) to directly estimate the FCBs. The details of FCB estimation are described with the Global Positioning System (GPS), BeiDou-2 Navigation Satellite System (BDS-2) and Galileo Navigation Satellite System (Galileo). For the estimated FCBs, the Root Mean Squares (RMSs) of the posterior residuals are smaller than 0.1 cycles, which indicates a high consistency for the float ambiguities. The stability of the WL FCBs series is better than 0.02 cycles for the three GNSS systems, while the STandard Deviation (STD) of the NL FCBs for BDS-2 is larger than 0.139 cycles. The combined FCBs have better stability than the raw series. With the multi-GNSS FCB products, the PPP AR for GPS/BDS-2/Galileo is demonstrated using the raw observations. For hourly static positioning results, the performance of the PPP AR with the three-system observations is improved by 42.6%, but only 13.1% for kinematic positioning results. The results indicate that precise and reliable positioning can be achieved with the PPP AR of GPS/BDS-2/Galileo, supported by multi-GNSS satellite orbit, clock, and FCB products based on iGMAS.

scholarly journals Performance evaluation of multi-GNSSs navigation in super synchronous transfer orbit and geostationary earth orbit

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Tao Shi ◽  
Xuebin Zhuang ◽  
Liwei Xie
Keyword(s):  
Global Navigation Satellite System ◽  
Autonomous Navigation ◽  
Satellite System ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Geostationary Earth Orbit ◽  
Beidou Navigation Satellite System ◽  
Transfer Orbit ◽  
High Orbit ◽  
Global Navigation Satellite

AbstractThe autonomous navigation of the spacecrafts in High Elliptic Orbit (HEO), Geostationary Earth Orbit (GEO) and Geostationary Transfer Orbit (GTO) based on Global Navigation Satellite System (GNSS) are considered feasible in many studies. With the completion of BeiDou Navigation Satellite System with Global Coverage (BDS-3) in 2020, there are at least 130 satellites providing Position, Navigation, and Timing (PNT) services. In this paper, considering the latest CZ-5(Y3) launch scenario of Shijian-20 GEO spacecraft via Super-Synchronous Transfer Orbit (SSTO) in December 2019, the navigation performance based on the latest BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), Galileo Navigation Satellite System (Galileo) and GLObal NAvigation Satellite System (GLONASS) satellites in 2020 is evaluated, including the number of visible satellites, carrier to noise ratio, Doppler, and Position Dilution of Precision (PDOP). The simulation results show that the GEO/Inclined Geo-Synchronous Orbit (IGSO) navigation satellites of BDS-3 can effectively increase the number of visible satellites and improve the PDOP in the whole launch process of a typical GEO spacecraft, including SSTO and GEO, especially for the GEO spacecraft on the opposite side of Asia-Pacific region. The navigation performance of high orbit spacecrafts based on multi-GNSSs can be significantly improved by the employment of BDS-3. This provides a feasible solution for autonomous navigation of various high orbit spacecrafts, such as SSTO, MEO, GEO, and even Lunar Transfer Orbit (LTO) for the lunar exploration mission.

APLICAÇÃO DE GEOTECNOLOGIAS NA ANÁLISE DE VIABILIDADE TÉCNICA E ECONÔMICA DO PROJETO DE IMPLANTAÇÃO DO IFMA - CAMPUS ITAQUI-BACANGA.

2021 ◽  
Vol 14 (2) ◽  
pp. 105
Author(s):  
Maelckson Bruno Barros Gomes ◽  
André Luis Silva Santos
Keyword(s):  
Real Time ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Real Time Kinematic ◽  
Global Navigation ◽  
Global Navigation Satellite

<p class="04CorpodoTexto">Este artigo tem por objetivo aplicar geotecnologias para obtenção de informações planialtimétricas a fim de avaliar a viabilidade de implantação do campus Centro Histórico/Itaqui-Bacanga do IFMA. Considerando que para realização de levantamento por métodos tradicionais é recomendado que seja realizado o destocamento e a limpeza do terreno previamente, avaliou-se a realização do levantamento planialtimétrico a partir de um par de receptores <em>Global Navigation Satellite System</em> (GNSS) pelo método <em>Real Time Kinematic</em> (RTK) pós processado e também a partir da realização de levantamento fotogramétrico, utilizando aeronave remotamente pilotada (ARP), popularmente conhecida como drone. Esta análise permitiu demonstrar que o aerolevantamento com a ARP pode ser aplicado na concepção inicial de um projeto de engenharia, conforme classificação do Tribunal de Contas da União (TCU) para níveis de precisão, pois obteve-se uma diferença orçamentária de 19% entre os projetos elaborados a partir das duas geotecnologias.</p><div> </div>

scholarly journals Assessment of BeiDou differential code bias variations from multi-GNSS network observations

2016 ◽  
Vol 34 (2) ◽  
pp. 259-269 ◽  
Author(s):  
S. G. Jin ◽  
R. Jin ◽  
D. Li
Keyword(s):  
Orbital Plane ◽  
Satellite Orbit ◽  
Satellite System ◽  
Global Navigation Satellite Systems ◽  
Dominant Factor ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Differential Code Bias ◽  
Code Bias ◽  
Gnss Network

Abstract. The differential code bias (DCB) of global navigation satellite systems (GNSSs) affects precise ionospheric modeling and applications. In this paper, daily DCBs of the BeiDou Navigation Satellite System (BDS) are estimated and investigated from 2-year multi-GNSS network observations (2013–2014) based on global ionospheric maps (GIMs) from the Center for Orbit Determination in Europe (CODE), which are compared with Global Positioning System (GPS) results. The DCB of BDS satellites is a little less stable than GPS solutions, especially for geostationary Earth orbit (GEO) satellites. The BDS GEO observations decrease the precision of inclined geosynchronous satellite orbit (IGSO) and medium Earth orbit (MEO) DCB estimations. The RMS of BDS satellites DCB decreases to about 0.2 ns when we remove BDS GEO observations. Zero-mean condition effects are not the dominant factor for the higher RMS of BDS satellites DCB. Although there are no obvious secular variations in the DCB time series, sub-nanosecond variations are visible for both BDS and GPS satellites DCBs during 2013–2014. For satellites in the same orbital plane, their DCB variations have similar characteristics. In addition, variations in receivers DCB in the same region are found with a similar pattern between BDS and GPS. These variations in both GPS and BDS DCBs are mainly related to the estimated error from ionospheric variability, while the BDS DCB intrinsic variation is in sub-nanoseconds.

scholarly journals Multi-GNSS Combined Precise Point Positioning Using Additional Observations with Opposite Weight for Real-Time Quality Control

2019 ◽  
Vol 11 (3) ◽  
pp. 311 ◽  
Author(s):  
Wenju Fu ◽  
Guanwen Huang ◽  
Yuanxi Zhang ◽  
Qin Zhang ◽  
Bobin Cui ◽  
...  
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Precise Point Positioning ◽  
Satellite System ◽  
Convergence Time ◽  
Navigation Satellite ◽  
Positioning Accuracy ◽  
Global Navigation ◽  
Point Positioning ◽  
Global Navigation Satellite

The emergence of multiple global navigation satellite systems (multi-GNSS), including global positioning system (GPS), global navigation satellite system (GLONASS), Beidou navigation satellite system (BDS), and Galileo, brings not only great opportunities for real-time precise point positioning (PPP), but also challenges in quality control because of inevitable data anomalies. This research aims at achieving the real-time quality control of the multi-GNSS combined PPP using additional observations with opposite weight. A robust multiple-system combined PPP estimation is developed to simultaneously process observations from all the four GNSS systems as well as single, dual, or triple systems. The experiment indicates that the proposed quality control can effectively eliminate the influence of outliers on the single GPS and the multiple-system combined PPP. The analysis on the positioning accuracy and the convergence time of the proposed robust PPP is conducted based on one week’s data from 32 globally distributed stations. The positioning root mean square (RMS) error of the quad-system combined PPP is 1.2 cm, 1.0 cm, and 3.0 cm in the east, north, and upward components, respectively, with the improvements of 62.5%, 63.0%, and 55.2% compared to those of single GPS. The average convergence time of the quad-system combined PPP in the horizontal and vertical components is 12.8 min and 12.2 min, respectively, while it is 26.5 min and 23.7 min when only using single-GPS PPP. The positioning performance of the GPS, GLONASS, and BDS (GRC) combination and the GPS, GLONASS, and Galileo (GRE) combination is comparable to the GPS, GLONASS, BDS and Galileo (GRCE) combination and it is better than that of the GPS, BDS, and Galileo (GCE) combination. Compared to GPS, the improvements of the positioning accuracy of the GPS and GLONASS (GR) combination, the GPS and Galileo (GE) combination, the GPS and BDS (GC) combination in the east component are 53.1%, 43.8%, and 40.6%, respectively, while they are 55.6%, 48.1%, and 40.7% in the north component, and 47.8%, 40.3%, and 34.3% in the upward component.

scholarly journals Determination of the Stability of High-Steep Slopes by Global Navigation Satellite System (GNSS) Real-Time Monitoring in Long Wall Mining

2020 ◽  
Vol 10 (6) ◽  
pp. 1952 ◽  
Author(s):  
Xugang Lian ◽  
Zoujun Li ◽  
Hongyan Yuan ◽  
Haifeng Hu ◽  
Yinfei Cai ◽  
...  
Keyword(s):  
Real Time ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Slope Movement ◽  
Navigation Satellite ◽  
Real Time Monitoring ◽  
Uniform Deformation ◽  
Working Face ◽  
Global Navigation Satellite ◽  
Steep Slopes

Surface movement and deformation induced by underground coal mining causes slopes to collapse. Global Navigation Satellite System (GNSS) real-time monitoring can provide early warnings and prevent disasters. A stability analysis of high-steep slopes was conducted in a long wall mine in China, and a GNSS real-time monitoring system was established. The moving velocity and displacement at the monitoring points were an integrated response to the influencing factors of mining, topography, and rainfall. Underground mining provided a continuous external driving force for slope movement, the steep terrain provided sufficient slip conditions in the slope direction, and rainfall had an acceleration effect on slope movement. The non-uniform deformation, displacement field, and time series images of the slope body revealed that ground failure was concentrated in the area of non-uniform deformation. The non-uniform deformation was concentrated ahead of the working face, the speed of deformation behind the working face was reduced, the instability of the slope body was increased, and the movement of the top of the slope was larger than at the foot. The high-steep slope stability in the mine was influenced by the starting deformation (low stability), iso-accelerated deformation (increased stability), deformation deceleration (reduced stability), and deformation remaining unchanged (improved stability).

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