Performance of BDS B1 frequency standard point positioning during the main phase of different classes of geomagnetic storms in China and its surrounding area

Abstract. Geomagnetic storms are one of the space weather events. The radio signals transmitted by modern navigation systems suffer from the effects of storms which can degrade the performance of the whole system. In this study, the performance of BeiDou Navigation Satellite System (BDS) B1 frequency standard point positioning in China and its surrounding area during different classes of storms is investigated for the first time. The analysis of the results revealed that BDS B1 frequency standard point positioning accuracy was deteriorated during the storms. The probability of the extrema in the statistics of positioning errors during strong storms is the largest, followed by moderate and weak storms. The positioning accuracy for storms of a similar class is found not to be at the same level. The root mean square error (RMSE) in position for the different classes of storms could be at least tens of centimeters in the East, North and Up directions.

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Reducing the Effect of Positioning Errors on Kinematic Raw Doppler (RD) Velocity Estimation Using BDS-2 Precise Point Positioning

Sensors ◽

10.3390/s19133029 ◽

2019 ◽

Vol 19 (13) ◽

pp. 3029 ◽

Cited By ~ 2

Author(s):

Duan ◽

Sun ◽

Ouyang ◽

Chen ◽

Shi

Keyword(s):

Precise Point Positioning ◽

Single Point ◽

Estimation Method ◽

Satellite System ◽

Velocity Estimation ◽

Navigation Satellite ◽

Positioning Accuracy ◽

Positioning Errors ◽

Point Positioning ◽

Global Navigation Satellite

In the traditional raw Doppler (RD) velocity estimation method, the positioning error of the pseudorange-based global navigation satellite system (GNSS) single point positioning (SPP) solution affects the accuracy of the velocity estimation through the station-satellite unit cosine vector. To eliminate the effect of positioning errors, this paper proposes a carrier-phase-based second generation of the BeiDou navigation satellite system (BDS-2) precise point positioning (PPP) RD velocity estimation method. Compared with the SPP positioning accuracy of tens of meters, the BDS-2 kinematic PPP positioning accuracy is significantly improved to the dm level. In order to verify the reliability and applicability of the developed method, three dedicated tests, the vehicle-borne, ship-borne and air-borne platforms, were conducted. In the vehicle-borne experiment, the GNSS and inertial navigation system (INS)-integrated velocity solution was chosen as the reference. The velocity accuracy of the BDS-2 PPP RD method was better than that of SPP RD by 28.4%, 27.1% and 26.1% in the east, north and up directions, respectively. In the ship-borne and air-borne experiments, the BDS-2 PPP RD velocity accuracy was improved by 17.4%, 21.4%, 17.8%, and 38.1%, 17.6%, 17.5% in the same three directions, respectively, compared with the BDS-2 SPP RD solutions. The reference in these two tests is the real-time kinematic (RTK) Position Derivation (PD)-based velocity.

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Performance Analysis of Static Precise Point Positioning Using Open-Source GAMP

Artificial Satellites ◽

10.2478/arsa-2020-0004 ◽

2020 ◽

Vol 55 (2) ◽

pp. 41-60

Author(s):

Jabir Shabbir Malik

Keyword(s):

Performance Analysis ◽

Open Source ◽

Observational Data ◽

Precise Point Positioning ◽

Three Dimensional ◽

Satellite System ◽

International Gnss Service ◽

Positioning Accuracy ◽

Position Accuracy ◽

Point Positioning

AbstractIn addition to Global Positioning System (GPS) constellation, the number of Global Navigation Satellite System (GLONASS) satellites is increasing; it is now possible to evaluate and analyze the position accuracy with both the GPS and GLONASS constellation. In this article, statistical analysis of static precise point positioning (PPP) using GPS-only, GLONASS-only, and combined GPS/GLONASS modes is evaluated. Observational data of 10 whole days from 10 International GNSS Service (IGS) stations are used for analysis. Position accuracy in east, north, up components, and carrier phase/code residuals is analyzed. Multi-GNSS PPP open-source package is used for the PPP performance analysis. The analysis also provides the GNSS researchers the understanding of the observational data processing algorithm. Calculation statistics reveal that standard deviation (STD) of horizontal component is 3.83, 13.80, and 3.33 cm for GPS-only, GLONASS-only, and combined GPS/GLONASS PPP solutions, respectively. Combined GPS/GLONASS PPP achieves better positioning accuracy in horizontal and three-dimensional (3D) accuracy compared with GPS-only and GLONASS-only PPP solutions. The results of the calculation show that combined GPS/GLONASS PPP improves, on an average, horizontal accuracy by 12.11% and 60.33% and 3D positioning accuracy by 10.39% and 66.78% compared with GPS-only and GLONASS-only solutions, respectively. In addition, the results also demonstrate that GPS-only solutions show an improvement of 54.23% and 62.54% compared with GLONASS-only PPP mode in horizontal and 3D components, respectively. Moreover, residuals of GLONASS ionosphere-free code observations are larger than the GPS code residuals. However, phase residuals of GPS and GLONASS phase observations are of the same magnitude.

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

Remote Sensing ◽

10.3390/rs11030311 ◽

2019 ◽

Vol 11 (3) ◽

pp. 311 ◽

Cited By ~ 3

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.

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Real-time Precise Point Positioning with a Xiaomi MI 8 Android Smartphone

Sensors ◽

10.3390/s19122835 ◽

2019 ◽

Vol 19 (12) ◽

pp. 2835 ◽

Cited By ~ 18

Author(s):

Bo Chen ◽

Chengfa Gao ◽

Yongsheng Liu ◽

Puyu Sun

Keyword(s):

Real Time ◽

Mobile Phones ◽

Precise Point Positioning ◽

Satellite System ◽

Dual Frequency ◽

Gnss Positioning ◽

Positioning Errors ◽

Positioning Method ◽

Point Positioning ◽

Time Required

The Global Navigation Satellite System (GNSS) positioning technology using smartphones can be applied to many aspects of mass life, and the world’s first dual-frequency GNSS smartphone Xiaomi MI 8 represents a new trend in the development of GNSS positioning technology with mobile phones. The main purpose of this work is to explore the best real-time positioning performance that can be achieved on a smartphone without reference stations. By analyzing the GNSS raw measurements, it is found that all the three mobile phones tested have the phenomenon that the differences between pseudorange observations and carrier phase observations are not fixed, thus a PPP (precise point positioning) method is modified accordingly. Using a Xiaomi MI 8 smartphone, the modified real-time PPP positioning strategy which estimates two clock biases of smartphone was applied. The results show that using multi-GNSS systems data can effectively improve positioning performance; the average horizontal and vertical RMS positioning error are 0.81 and 1.65 m respectively (using GPS, BDS, and Galileo data); and the time required for each time period positioning errors in N and E directions to be under 1 m is less than 30s.

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Study on Multi-GNSS Precise Point Positioning Performance with Adverse Effects of Satellite Signals on Android Smartphone

Sensors ◽

10.3390/s20226447 ◽

2020 ◽

Vol 20 (22) ◽

pp. 6447

Author(s):

Hongyu Zhu ◽

Linyuan Xia ◽

Dongjin Wu ◽

Jingchao Xia ◽

Qianxia Li

Keyword(s):

Adverse Effects ◽

Precise Point Positioning ◽

Phase Error ◽

Three Dimensional ◽

Satellite System ◽

Dual Frequency ◽

Positioning Accuracy ◽

Noise Ratio ◽

Point Positioning ◽

Gnss Observations

The emergence of dual frequency global navigation satellite system (GNSS) chip actively promotes the progress of precise point positioning (PPP) technology in Android smartphones. However, some characteristics of GNSS signals on current smartphones still adversely affect the positioning accuracy of multi-GNSS PPP. In order to reduce the adverse effects on positioning, this paper takes Huawei Mate30 as the experimental object and presents the analysis of multi-GNSS observations from the aspects of carrier-to-noise ratio, cycle slip, gradual accumulation of phase error, and pseudorange residual. Accordingly, we establish a multi-GNSS PPP mathematical model that is more suitable for GNSS observations from a smartphone. The stochastic model is composed of GNSS step function variances depending on carrier-to-noise ratio, and the robust Kalman filter is applied to parameter estimation. The multi-GNSS experimental results show that the proposed PPP method can significantly reduce the effect of poor satellite signal quality on positioning accuracy. Compared with the conventional PPP model, the root mean square (RMS) of GPS/BeiDou (BDS)/GLONASS static PPP horizontal and vertical errors in the initial 10 min decreased by 23.71% and 62.06%, respectively, and the horizontal positioning accuracy reached 10 cm within 100 min. Meanwhile, the kinematic PPP maximum three-dimensional positioning error of GPS/BDS/GLONASS decreased from 16.543 to 10.317 m.

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Multi-GNSS real-time orbit and clock quality changes over time

10.5194/egusphere-egu21-7160 ◽

2021 ◽

Author(s):

Kamil Kazmierski ◽

Radoslaw Zajdel ◽

Krzysztof Sośnica

Keyword(s):

Real Time ◽

Orbital Plane ◽

Satellite System ◽

Quality Level ◽

Navigation Systems ◽

Positioning Errors ◽

Time Regime ◽

Changes Over Time ◽

Strategy Changes

Navigation systems have substantially evolved in the last decade. The multi-GNSS constellation including GPS, GLONASS, Galileo, and BeiDou consists of more than a hundred active satellites. To fully exploit their potential, users should be able to take advantage of those systems not only in postprocessing mode employing final solutions but also in real-time. It is also important to make satellite signals highly useful in a real-time regime not only in standard positioning mode but also with the precise positioning technique. That is why real-time products are highly desirable. One of the IGS Analysis Centers that support multi-GNSS real-time solution is CNES which provides not only orbits and clocks but also code and phase biases and VTEC global maps. Over the last few years, real-time products have been changing similarly to navigation systems, which come along with observation availability and calculation strategy changes.We utilize the signal-in-space ranging error (SISRE) as the main orbit and clock quality indicator. Additionally, SLR observations are used as an independent source of information about orbit quality. Three years of data, between 2017 and 2020, are used to check the progress in the quality of the delivered products to the users through the internet streams provided by CNES.The progress in the product quality in the test period is obvious and it depends on the satellite system, block or satellite type, time, and the height of the Sun above the orbital plane. The most accurate orbits are available for GPS, however, the very stable atomic clocks of Galileo compensate for systematic errors in Galileo orbits. Consequently, the SISRE for Galileo is lower than that for GPS, equaling 1.6 and 2.3 cm for Galileo and GPS, respectively. The SISRE value for GLONASS, despite the good quality of the orbits, is disturbed by the lower quality of the onboard clocks and is equal to 4-6 cm. The same quality level is for BeiDou-2 MEO and IGSO satellites. Products for BeiDou-2 GEO satellites are less accurate and with poor availability due to a large number of satellite maneuvers, thus they are not very useful for real-time positioning.For positioning purposes, the presented results may be interesting especially in the context of the proper observation weighting in the multi-GNSS combinations. It is worth mentioning that the quality of the real-time products is not constant and neglecting this fact may bring undesirable positioning errors, especially for long processing campaigns.

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Integration of multi-constellation GNSS precise point positioning and MEMS-based inertial system for precise applications

10.32920/ryerson.14644260.v1 ◽

2021 ◽

Author(s):

Mahmoud Abd Rabbou

Keyword(s):

Precise Point Positioning ◽

Low Cost ◽

Satellite System ◽

Integrated System ◽

Inertial System ◽

Integrated Navigation ◽

Positioning Accuracy ◽

Phase Measurements ◽

Point Positioning ◽

Inertial Measurements

This dissertation develops a low-cost integrated navigation system, which integrates multi-constellation global navigation satellite system (GNSS) precise point positioning (PPP) with a low-cost micro-electro-mechanical sensor (MEMS)-based inertial system for precise applications. Both undifferenced and between-satellite single-difference (BSSD) ionosphere-free linear combinations of pseudorange and carrier phase measurements from three GNSS constellations, namely GPS, GLONASS and Galileo, are processed. An improved version of the PF, the unscented particle filter (UPF), which combines the UKF and the PF, is developed to merge the corrected GNSS satellite difference observations and inertial measurements and estimate inertial measurements biases and errors. The performance of the proposed integrated system is analyzed using real test scenarios. A tightly coupled GPS PPP/MEMS-based inertial system is first developed using EKF, which shows that decimeter-level positioning accuracy is achievable with both undifferenced and BSSD modes. However, in general, better positioning precision is obtained when BSSD linear combination is used. During GPS outages, the integrated system shows submeter-level accuracy in most cases when a 60-second outage is introduced. However, the positioning accuracy is improved to a few decimeter- and decimeter-level accuracy when 30- and 10-second GPS outages are introduced, respectively. The use of UPF, on the other hand, reduces the number of samples significantly, in comparison with the traditional PF. Additionally, in comparison with EKF, the use of UPF improves the positioning accuracy during the 60-second GPS outages by 14%, 13% and 15% in latitude, longitude and altitude, respectively. The addition of GLONASS and Galileo observations to the developed integrated system shows that decimeter- to centimeter-level positioning accuracy is achievable when the GNSS measurement updates are available. In comparison with the GPS-based integrated system, the multi-constellation GNSS PPP/MEMS-based inertial system improves the latitude, longitude and altitude components precision by 24%, 41% and 41%, respectively. In addition, the use of BSSD mode improves the precision of the latitude, longitude and altitude components by 23%, 15% and 13%, respectively, in comparison with the undifferenced mode. During complete GNSS outages, the developed integrated system continues to achieve decimeter-level accuracy for up to 30 seconds, while it achieves submeter-level accuracy when a 60-second outage is introduced.

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Assessment of BeiDou-3 and Multi-GNSS Precise Point Positioning Performance

Sensors ◽

10.3390/s19112496 ◽

2019 ◽

Vol 19 (11) ◽

pp. 2496 ◽

Cited By ~ 14

Author(s):

Guoqiang Jiao ◽

Shuli Song ◽

Yulong Ge ◽

Ke Su ◽

Yangyang Liu

Keyword(s):

Precise Point Positioning ◽

Geographic Area ◽

Satellite System ◽

Assessment System ◽

Convergence Time ◽

Navigation Satellite ◽

Positioning Accuracy ◽

Kinematic Positioning ◽

Global Coverage ◽

Point Positioning

With the launch of BDS-3 and Galileo new satellites, the BeiDou navigation satellite system (BDS) has developed from the regional to global system, and the Galileo constellation will consist of 26 satellites in space. Thus, BDS, GPS, GLONASS, and Galileo all have the capability of global positioning services. It is meaningful to evaluate the ability of global precise point positioning (PPP) of the GPS, BDS, GLONASS, and Galileo. This paper mainly contributes to the assessment of BDS-2, BDS-2/BDS-3, GPS, GLONASS, and Galileo PPP with the observations that were provided by the international Global Navigation Satellite System (GNSS) Monitoring and Assessment System (iGMAS). The Position Dilution of Precision (PDOP) value was utilized to research the global coverage of GPS, BDS-2, BDS-2/BDS-3, GLONASS, and Galileo. In particular, GPS-only, BDS-2-only, BDS-2/BDS-3, GLONASS-only, Galileo-only, and multi-GNSS combined PPP solutions were analyzed to verify the capacity of the PPP performances in terms of positioning accuracy, convergence time, and zenith troposphere delay (ZTD) accuracy. In view of PDOP, the current BDS and Galileo are capable of global coverage. The BDS-2/BDS-3 and Galileo PDOP values are fairly evenly distributed around the world similar to GPS and GLONASS. The root mean square (RMS) of positioning errors for static BDS-2/BDS-3 PPP and Galileo-only PPP are 10.7, 19.5, 20.4 mm, and 6.9, 18.6, 19.6 mm, respectively, in the geographic area of the selected station, which is the same level as GPS and GLONASS. It is worth mentioning that, by adding BDS-3 observations, the positioning accuracy of static BDS PPP is improved by 17.05%, 24.42%, and 35.65%, and the convergence time is reduced by 27.15%, 27.87%, and 35.76% in three coordinate components, respectively. Similar to the static positioning, GPS, BDS-2/BDS-3, GLONASS, and Galileo have the basically same kinematic positioning accuracy. Multi-GNSS PPP significantly improves the positioning performances in both static and kinematic positioning. In terms of ZTD accuracy, the difference between GPS, BDS-2/BDS-3, GLONASS, and Galileo is less than 1 mm, and the BDS-2/BDS-3 improves ZTD accuracy by 20.48% over the BDS-2. The assessment of GPS, BDS-2, BDS-2/BDS-3, GLONASS, Galileo, and multi-GNSS global PPP performance are shown to make comments for the development of multi-GNSS integration, global precise positioning, and the construction of iGMAS.

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Semi-tightly coupled integration of multi-GNSS PPP and S-VINS for precise positioning in GNSS-challenged environments

Satellite Navigation ◽

10.1186/s43020-020-00033-9 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Xingxing Li ◽

Xuanbin Wang ◽

Jianchi Liao ◽

Xin Li ◽

Shengyu Li ◽

...

Keyword(s):

Global Navigation Satellite System ◽

Inertial Navigation ◽

Satellite System ◽

Navigation Satellite ◽

Navigation Systems ◽

Tight Coupling ◽

Positioning Accuracy ◽

3D Positioning ◽

Global Navigation ◽

Global Navigation Satellite

AbstractBecause of its high-precision, low-cost and easy-operation, Precise Point Positioning (PPP) becomes a potential and attractive positioning technique that can be applied to self-driving cars and drones. However, the reliability and availability of PPP will be significantly degraded in the extremely difficult conditions where Global Navigation Satellite System (GNSS) signals are blocked frequently. Inertial Navigation System (INS) has been integrated with GNSS to ameliorate such situations in the last decades. Recently, the Visual-Inertial Navigation Systems (VINS) with favorable complementary characteristics is demonstrated to realize a more stable and accurate local position estimation than the INS-only. Nevertheless, the system still must rely on the global positions to eliminate the accumulated errors. In this contribution, we present a semi-tight coupling framework of multi-GNSS PPP and Stereo VINS (S-VINS), which achieves the bidirectional location transfer and sharing in two separate navigation systems. In our approach, the local positions, produced by S-VINS are integrated with multi-GNSS PPP through a graph-optimization based method. Furthermore, the accurate forecast positions with S-VINS are fed back to assist PPP in GNSS-challenged environments. The statistical analysis of a GNSS outage simulation test shows that the S-VINS mode can effectively suppress the degradation of positioning accuracy compared with the INS-only mode. We also carried out a vehicle-borne experiment collecting multi-sensor data in a GNSS-challenged environment. For the complex driving environment, the PPP positioning capability is significantly improved with the aiding of S-VINS. The 3D positioning accuracy is improved by 49.0% for Global Positioning System (GPS), 40.3% for GPS + GLOANSS (Global Navigation Satellite System), 45.6% for GPS + BDS (BeiDou navigation satellite System), and 51.2% for GPS + GLONASS + BDS. On this basis, the solution with the semi-tight coupling scheme of multi-GNSS PPP/S-VINS achieves the improvements of 41.8–60.6% in 3D positioning accuracy compared with the multi-GNSS PPP/INS solutions.

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Improving the Performance of Galileo Uncombined Precise Point Positioning Ambiguity Resolution Using Triple-Frequency Observations

Remote Sensing ◽

10.3390/rs11030341 ◽

2019 ◽

Vol 11 (3) ◽

pp. 341 ◽

Cited By ~ 8

Author(s):

Gen Liu ◽

Xiaohong Zhang ◽

Pan Li

Keyword(s):

Ambiguity Resolution ◽

Precise Point Positioning ◽

Simulated Data ◽

Satellite System ◽

Dual Frequency ◽

Positioning Accuracy ◽

Processing Mode ◽

Beidou Navigation Satellite System ◽

Triple Frequency ◽

Point Positioning

Compared with the traditional ionospheric-free linear combination precise point positioning (PPP) model, the un-differenced and uncombined (UDUC) PPP model using original observations can keep all the information of the observations and be easily extended to any number of frequencies. However, the current studies about the multi-frequency UDUC-PPP ambiguity resolution (AR) were mainly based on the triple-frequency BeiDou navigation satellite system (BDS) observations or simulated data. Limited by many factors, for example the accuracy of BDS precise orbit and clock products, the advantages of triple-frequency signals to UDUC-PPP AR were not fully exploited. As Galileo constellations have been upgraded by increasing the number of 19 useable satellites, it makes using Galileo satellites to further study the triple-frequency UDUC-PPP ambiguity resolution (AR) possible. In this contribution, we proposed the method of multi-frequency step-by-step ambiguity resolution based on the UDUC-PPP model and gave the reason why the performance of PPP AR can be improved using triple-frequency observations. We used triple-frequency Galileo observations on day of year (DOY) 201, 2018 provided by 166 Multi-GNSS Experiment (MGEX) stations to estimate original uncalibrated phase delays (UPD) on each frequency and to conduct both dual- and triple-frequency UDUC-PPP AR. The performance of UDUC-PPP AR based on post-processing mode was assessed in terms of the time-to-first-fix (TTFF) as well as positioning accuracy with 2-hour observations. It was found that triple-frequency observations were helpful to reduce TTFF and improve the positioning accuracy. The current statistic results showed that triple-frequency PPP-AR reduced the averaged TTFF by 19.6 % and also improved the positioning accuracy by 40.9, 31.2 and 23.6 % in the east, north and up directions respectively, compared with dual-frequency PPP-AR. With an increasing number of Galileo satellites, it is expected that the robustness and accuracy of the triple-frequency UCUD-PPP AR can be improved further.

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