scholarly journals Six-Year BDS-2 Broadcast Navigation Message Analysis from 2013 to 2018: Availability, Anomaly, and SIS UREs Assessment

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2767 ◽  
Author(s):  
Chenhao Ouyang ◽  
Junbo Shi ◽  
Yuru Shen ◽  
Lihong Li
Keyword(s):  
Anomaly Detection ◽  
Space Vehicle ◽  
Satellite Orbit ◽  
Satellite System ◽  
Asia Pacific ◽  
Earth Orbit ◽  
International Gnss Service ◽  
Worst Case ◽  
Navigation Message ◽  
Regional Service

The second-generation of the Beidou Navigation Satellite System (BDS-2) has been officially providing positioning, navigation, and timing (PNT) services within the Asia–Pacific region for six years, starting from 2013. A comprehensive analysis of BDS-2 satellite broadcast navigation message performance during the past six years is highly demanded, not only for the regional service but also for the global service announced in December 2018. Therefore, this study focuses on the performance assessment of six-year BDS-2 broadcast navigation messages from 2013 to 2018 in three aspects: Message availability, anomaly detection, and signal-in-space user range errors (SIS UREs). Firstly, our results, based on International GNSS service (IGS) Multi-GNSS Experiment (MGEX) navigation files, indicate that the BDS-2 Geosynchronous Earth Orbit (GEO) and Inclined Geosynchronous Satellite Orbit (IGSO) satellites have >98.51% broadcast navigation message availability, and the Medium Earth Orbit (MEO) satellites has a ~90.03% availability. Secondly, the comparison between broadcast navigation messages and IGS precise products reveals that the User Range Accuracy Index (URAI) contained in the broadcast message could not reflect satellite performance correctly. Another satellite status indicator, space vehicle (SV) health, can only partially detect a satellite anomaly. The anomaly detection result using IGS precise products for reference shows 20241 anomalies out of 651038 broadcast navigation messages within six years. Finally, compared with the IGSO and MEO satellites, the orbit qualities of GEO satellites are significantly worse due to their large along-track orbit error. The clock performance of all satellites are at the comparable level. The satellite orbit type (GEO/IGSO/MEO) does not impact the orbit-only URE, global-average URE, and worst-case URE.

Assessment and Impact on BDS Positioning Performance Analysis of Recent BDS IGSO-6 Satellite

2018 ◽  
Vol 71 (3) ◽  
pp. 729-748 ◽  
Author(s):  
Yidong Lou ◽  
Xianjie Li ◽  
Fu Zheng ◽  
Yang Liu ◽  
Hailin Guo
Keyword(s):  
Power Level ◽  
Single Point ◽  
Satellite Orbit ◽  
Satellite System ◽  
Convergence Time ◽  
Asia Pacific ◽  
Comparable Performance ◽  
Regional Service ◽  
Point Positioning ◽  
Density Ratios

The BeiDou navigation satellite system (BDS) has been providing a regional service in the Asia–Pacific area since 27 December 2012, and a new Inclined Geosynchronous Satellite Orbit (IGSO) satellite IGSO-6 joined the 14-satellite constellation in operation on 29 March 2016. In this paper, the signal and positioning performance of IGSO-6 are assessed. Compared with other IGSOs, the carrier-to-noise-density ratios of IGSO-6 show comparable performance for the B3 signal and a lower power level for the B2 signal, while the B1 signal is more powerful and has the lowest noise and multipath errors. The satellite-induced code bias of IGSO-6 was investigated and indicates that IGSO-6 has similar characteristics to other IGSOs. The different inter-frequency bias variations among IGSOs with daily periodicity are demonstrated. The BDS positioning performances with IGSO-6 were investigated in Single Point Positioning (SPP) and Precise Point Positioning (PPP) modes at the 95% confidence level. For SPP, there was an improvement of about 4·9% and 3·6% in the horizontal and vertical components, respectively. The convergence time was improved by about 18·3% and 17·8% in the horizontal and vertical components for positioning accuracy to be better than 50 cm, respectively.

scholarly journals An In-Depth Assessment of the New BDS-3 B1C and B2a Signals

2021 ◽  
Vol 13 (4) ◽  
pp. 788
Author(s):  
Qinghua Zhang ◽  
Yongxing Zhu ◽  
Zhengsheng Chen
Keyword(s):  
Carrier Phase ◽  
Density Ratio ◽  
Signal Strength ◽  
Satellite Orbit ◽  
Satellite System ◽  
Earth Orbit ◽  
Base Line ◽  
Signal Characteristics ◽  
Better Than

An in-depth and comprehensive assessment of new observations from BDS-3 satellites is presented, with the main focus on the Carrier-to-Noise density ratio (C/N0), the quality of code and carrier phase observations for B1C and B2a signal. The signal characteristics of geosynchronous earth orbit (GEO), inclined geosynchronous satellite orbit (IGSO) and medium earth orbit (MEO) satellites of BDS-3 were grouped and compared, respectively. The evaluation results of the new B1C and B2a signals of BDS-3 were compared with the previously B1I/B2I/B3I signals and the interoperable signals of GPS, Galileo and quasi-zenith satellite system (QZSS) were compared simultaneously. As expected, the results clearly show that B1C and B2a have better signal strength and higher accuracy, including code and carrier phase observations. The C/N0 of the B2a signal is about 3 dB higher than other signals. One exception is the code observation accuracy of B3I, which value is less than 0.15 m. The carrier precision of B1C and B2a is better than that of B1I/B2I/B3I. Despite difference-in-difference (DD) observation quantity or zero-base line evaluation is adopted, while B1C is about 0.3 mm higher carrier precision than B2a. The BDS-3 MEO satellite and GPS, Galileo, and QZSS satellites have the same level of signal strength, code and phase observation accuracy at the interoperable frequency, namely 1575.42 MHz and 1176.45 MHz which are very suitable for the co-position application.

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 Analyzing the Satellite-Induced Code Bias Variation Characteristics for the BDS-3 Via a 40 m Dish Antenna

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1339 ◽  
Author(s):  
Ju Hong ◽  
Rui Tu ◽  
Rui Zhang ◽  
Lihong Fan ◽  
Pengfei Zhang ◽  
...  
Keyword(s):  
New Technology ◽  
Satellite Orbit ◽  
Satellite System ◽  
Low Noise ◽  
Earth Orbit ◽  
Precision Positioning ◽  
Time Service ◽  
Frequency Bands ◽  
Variation Characteristics ◽  
Code Bias

The satellite-induced code bias variation of geostationary satellite orbit satellites and medium earth orbit satellites of the second-generation BeiDou Navigation Satellite System (BDS-2) exceeds 1 m, which severely affects the accuracy and stability of the ambiguity resolution and high-precision positioning. With the development of the third-generation BDS (BDS-3) with a new system design and new technology, analysis of the satellite-induced code variation characteristics of BDS-3 has become increasingly important. At present, many scholars have explored the satellite-induced code bias of BDS-3, but most of them focus on BDS-3 experimental satellites via normal geodetic antenna. Compared to normal geodetic antenna, the 40-m dish antenna from the National Time Service Center can accurately detect satellite-induced code variations with low noise and high gain. Thus, observational data from fifteen BDS-3 medium earth orbit satellites are collected with the B1I/B2b/B3I/B1C/B2a frequency bands on the day of year (DOY) 199–206 in 2019, the PRN numbers of which are C19/C20/C21/C22/C23/C24/C25/C26/C27/C28/C30/C32/C33 /C35/C37, via the 40 m dish antenna to analyze the code bias variation characteristics. The results show that the obvious satellite-induced elevation‑dependent code bias variations exist in the B1I/B2b/B3I/B1C/B2a frequency bands of C28, compared with other satellites. Similarly, the multipath (MP) combination of B3I has an obvious elevation‑dependent variation within a range of 0.1 m for C21/C24/C27/C28/C37 and elevation‑dependent variation of the B2a and B2b frequency bands also exists in most satellites with a range of 0.1 m. However, the MP combination values of some satellites are asymmetric with respect to elevation, which is different from BDS-2 satellites and especially obvious for BDS-3 satellites B1I and BIC frequency bands with elevation‑dependent variations of 0.2 m, indicating that the code bias variation is not uniquely related to elevation, especially for the B1I/BIC frequency bands. What’s more, the satellite-induced code bias variation of the BDS-3 satellites is greatly reduced compared with that of the BDS-2 satellites. In addition, the similar code bias variation appears at the Xia1 station with a normal geodetic antenna of B1I/B1C/B3I/B2a/B2b of C21, B3I/B2a/B2b of C24 and B2b of C28 among B1I/B1C/B3I/B2a/B2b of C21/C24/C27/C28/C37. The influence of the BDS-3 satellite-induced elevation‑dependent code bias on precision positioning and ambiguity fixing is worth further study using different antennas or receivers.

scholarly journals GA-ARMA Model for Predicting IGS RTS Corrections

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Mingyu Kim ◽  
Jeongrae Kim
Keyword(s):  
Real Time ◽  
Moving Average ◽  
Arma Model ◽  
Satellite Orbit ◽  
Satellite System ◽  
Prediction Performance ◽  
Data Loss ◽  
International Gnss Service ◽  
Time Service ◽  
Hardware Failures

The global navigation satellite system (GNSS) is widely used to estimate user positions. For precise positioning, users should correct for GNSS error components such as satellite orbit and clock errors as well as ionospheric delay. The international GNSS service (IGS) real-time service (RTS) can be used to correct orbit and clock errors in real-time. Since the IGS RTS provides real-time corrections via the Internet, intermittent data loss can occur due to software or hardware failures. We propose applying a genetic algorithm autoregressive moving average (GA-ARMA) model to predict the IGS RTS corrections during data loss periods. The RTS orbit and clock corrections are predicted up to 900 s via the GA-ARMA model, and the prediction accuracies are compared with the results from a generic ARMA model. The orbit prediction performance of the GA-ARMA is nearly equivalent to that of ARMA, but GA-ARMA’s clock prediction performance is clearly better than that of ARMA, achieving a 32% error reduction. Predicted RTS corrections are applied to the broadcast ephemeris, and precise point positioning accuracies are compared. GA-ARMA shows a significant accuracy improvement over ARMA, particularly in terms of vertical positioning.

Performance analysis of BDS/GPS kinematic vehicle positioning in various observation conditions

Sensor Review ◽  
2016 ◽  
Vol 36 (3) ◽  
pp. 249-256 ◽  
Author(s):  
Xin Li ◽  
Jiming Guo ◽  
Lv Zhou
Keyword(s):  
Urban Area ◽  
Satellite System ◽  
Asia Pacific ◽  
Navigation Satellite ◽  
Content Type ◽  
Kinematic Positioning ◽  
Constrained Environments ◽  
Regional Service ◽  
Vehicle Positioning ◽  
Global Navigation Satellite

Purpose Global positioning system (GPS) kinematic positioning suffers from performance degradation in constrained environments such as urban canyons, which then restricts the application of high-precision vehicle positioning and navigation within the city. In December 2012, the BeiDou Navigation Satellite System (BDS) regional service was announced, and the combined BDS/GPS kinematic positioning has been enabled in the Asia-Pacific area. Previous studies have mainly focused on the performance evaluations of combined BDS/GPS static positioning. Not much work has been performed for kinematic vehicle positioning under constrained observation conditions. This study aims to analyze the performance of BDS/GPS kinematic vehicle positioning in various conditions. Design/methodology/approach In this study, three vehicle experiments under three observation conditions, an open suburban area, a less dense non-central urban area and a dense central urban area, are investigated using both the code-based differential global navigation satellite system (DGNSS) and phase-based real-time kinematic (RTK) modes. The comparison between combined BDS/GPS and GPS-only vehicle positioning solutions is conducted in terms of positioning availability and positioning precision. Findings Numerical results show that the combined BDS/GPS system significantly outperforms the GPS-only system under poor observation conditions, whereas the improvement was less significant under good observation conditions. Originality/value Thus, this paper studies the performance of combined BDS/GPS kinematic relative positioning under various observation conditions.

scholarly journals Assessment of Centre National d’Études Spatiales Real-Time Ionosphere Maps in Instantaneous Precise Real-Time Kinematic Positioning over Medium and Long Baselines

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2293 ◽  
Author(s):  
Dariusz Tomaszewski ◽  
Paweł Wielgosz ◽  
Jacek Rapiński ◽  
Anna Krypiak-Gregorczyk ◽  
Rafał Kaźmierczak ◽  
...  
Keyword(s):  
Real Time ◽  
A Priori ◽  
Satellite Orbit ◽  
Satellite System ◽  
Ionospheric Delay ◽  
Reference Station ◽  
Atmospheric Effects ◽  
International Gnss Service ◽  
Real Time Kinematic ◽  
Global Navigation Satellite

Precise real-time kinematic (RTK) Global Navigation Satellite System (GNSS) positioning requires fixing integer ambiguities after a short initialization time. Originally, it was assumed that it was only possible at a relatively short distance from a reference station (<10 km), because otherwise the atmospheric effects prevent effective ambiguity fixing. Nowadays, through the use of VRS, MAC, or FKP corrections, the distances to the closest reference station have been increased to around 35 km. However, the baselines resolved in real time are not as far as in the case of static positioning. Further extension of the baseline requires the use of an ionosphere-weighted model with ionospheric delay corrections available in real time. This solution is now possible thanks to the Radio Technical Commission for Maritime (RTCM) stream of SSR corrections from, for example, Centre National d’Études Spatiales (CNES), the first analysis center to provide it in the context of the International GNSS Service. Then, ionospheric delays are treated as pseudo-observations that have a priori values from the CLK RTCM stream. Additionally, satellite orbit and clock errors are properly considered using space-state representation (SSR) real-time radial, along-track, and cross-track corrections. The following paper presents the initial results of such RTK positioning. Measurements were performed in various field conditions reflecting realistic scenarios that could have been experienced by actual RTK users. We have shown that the assumed methodology was suitable for single-epoch RTK positioning with up to 82 km baseline in solar minimum (30 March 2019) mid and high latitude (Olsztyn, Poland) conditions. We also confirmed that it is possible to obtain a rover position at the level of a few centimeters of precision. Finally, the possibility of using other newer experimental IGS RT Global Ionospheric Maps (GIMs), from Chinese Academy of Sciences (CAS) and Universitat Politècnica de Catalunya (UPC) among CNES, is discussed in terms of their recent performance in the ionospheric delay domain.

Performance Evaluation of the CNAV Broadcast Ephemeris

2019 ◽  
Vol 72 (5) ◽  
pp. 1331-1344
Author(s):  
Ahao Wang ◽  
Junping Chen ◽  
Yize Zhang ◽  
Jiexian Wang ◽  
Bin Wang
Keyword(s):  
Global Navigation Satellite System ◽  
Single Point ◽  
Satellite Orbit ◽  
Satellite System ◽  
Single Frequency ◽  
Navigation Satellite ◽  
Dual Frequency ◽  
Navigation Message ◽  
Global Navigation ◽  
Global Navigation Satellite

The new Global Positioning System (GPS) Civil Navigation Message (CNAV) has been transmitted by Block IIR-M and Block IIF satellites since April 2014, both on the L2C and L5 signals. Compared to the Legacy Navigation Message (LNAV), the CNAV message provides six additional parameters (two orbit parameters and four Inter-Signal Correction (ISC) parameters) for prospective civil users. Using the precise products of the International Global Navigation Satellite System Service (IGS), we evaluate the precision of satellite orbit, clock and ISCs of the CNAV. Additionally, the contribution of the six new parameters to GPS Single Point Positioning (SPP) is analysed using data from 22 selected Multi-Global Navigation Satellite System Experiment (MGEX) stations from a 30-day period. The results indicate that the CNAV/LNAV Signal-In-Space Range Error (SISRE) and orbit-only SISRE from January 2016 to March 2018 is of 0·5 m and 0·3 m respectively, which is improved in comparison with the results from an earlier period. The ISC precision of L1 Coarse/Acquisition (C/A) is better than 0·1 ns, and those of L2C and L5Q5 are about 0·4 ns. Remarkably, ISC correction has little effect on the single-frequency SPP for GPS users using civil signals (for example, L1C, L2C), whereas dual-frequency SPP with the consideration of ISCs results have an accuracy improvement of 18·6%, which is comparable with positioning accuracy based on an ionosphere-free combination of the L1P (Y) and L2P (Y) signals.

scholarly journals Precise Orbit Determination for BeiDou GEO/IGSO Satellites during Orbit Maneuvering with Pseudo-Stochastic Pulses

2019 ◽  
Vol 11 (21) ◽  
pp. 2587
Author(s):  
Qin ◽  
Huang ◽  
Zhang ◽  
Wang ◽  
Yan ◽  
...  
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Satellite System ◽  
Assessment System ◽  
Asia Pacific ◽  
Earth Orbit ◽  
Observation Data ◽  
Navigation Satellite ◽  
Precise Orbit ◽  
Global Navigation Satellite

In order to provide better service for the Asia-Pacific region, the BeiDou navigation satellite system (BDS) is designed as a constellation containing medium earth orbit (MEO), geostationary earth orbit (GEO), and inclined geosynchronous orbit (IGSO). However, the multi-orbit configuration brings great challenges for orbit determination. When orbit maneuvering, the orbital elements of the maneuvered satellites from broadcast ephemeris are unusable for several hours, which makes it difficult to estimate the initial orbit in the process of precise orbit determination. In addition, the maneuvered force information is unknown, which brings systematic orbit integral errors. In order to avoid these errors, observation data are removed from the iterative adjustment. For the above reasons, the precise orbit products of maneuvered satellites are missing from IGS (international GNSS (Global Navigation Satellite System) service) and iGMAS (international GNSS monitoring and assessment system). This study proposes a method to determine the precise orbits of maneuvered satellites for BeiDou GEO and IGSO. The initial orbits of maneuvered satellites could be backward forecasted according to the precise orbit products. The systematic errors caused by unmodeled maneuvered force are absorbed by estimated pseudo-stochastic pulses. The proposed method for determining the precise orbits of maneuvered satellites is validated by analyzing data of stations from the Multi-GNSS Experiment (MGEX). The results show that the precise orbits of maneuvered satellites can be estimated correctly when orbit maneuvering, which could supplement the precise products from the analysis centers of IGS and iGMAS. It can significantly improve the integrality and continuity of the precise products and subsequently provide better precise products for users.

scholarly journals BeiDou Augmented Navigation from Low Earth Orbit Satellites

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 198 ◽  
Author(s):  
Mudan Su ◽  
Xing Su ◽  
Qile Zhao ◽  
Jingnan Liu
Keyword(s):  
Simulated Data ◽  
Slow Motion ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Convergence Time ◽  
Asia Pacific ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Beidou Navigation Satellite System ◽  
Global Navigation Satellite

Currently, the Global Navigation Satellite System (GNSS) mainly uses the satellites in Medium Earth Orbit (MEO) to provide position, navigation, and timing (PNT) service. The weak navigation signals limit its usage in deep attenuation environments, and make it easy to interference and counterfeit by jammers or spoofers. Moreover, being far away to the Earth results in relatively slow motion of the satellites in the sky and geometric change, making long time needed for achieved centimeter positioning accuracy. By using the satellites in Lower Earth Orbit (LEO) as the navigation satellites, these disadvantages can be addressed. In this contribution, the advantages of navigation from LEO constellation has been investigated and analyzed theoretically. The space segment of global Chinese BeiDou Navigation Satellite System consisting of three GEO, three IGSO, and 24 MEO satellites has been simulated with a LEO constellation with 120 satellites in 10 orbit planes with inclination of 55 degrees in a nearly circular orbit (eccentricity about 0.000001) at an approximate altitude of 975 km. With simulated data, the performance of LEO constellation to augment the global Chinese BeiDou Navigation Satellite System (BeiDou-3) has been assessed, as one of the example to show the promising of using LEO as navigation system. The results demonstrate that the satellite visibility and position dilution of precision have been significantly improved, particularly in mid-latitude region of Asia-Pacific region, once the LEO data were combined with BeiDou-3 for navigation. Most importantly, the convergence time for Precise Point Positioning (PPP) can be shorted from about 30 min to 1 min, which is essential and promising for real-time PPP application. Considering there are a plenty of commercial LEO communication constellation with hundreds or thousands of satellites, navigation from LEO will be an economic and promising way to change the heavily relay on GNSS systems.

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