scholarly journals First results of BDS positioning for LBS applications in the UK

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Yan Xia ◽  
Xiaolin Meng ◽  
Yusong Yang ◽  
Shuguo Pan ◽  
Qing Zhao ◽  
...  
Keyword(s):  
Density Ratio ◽  
Satellite System ◽  
Location Based Services ◽  
Navigation Satellite ◽  
Location Services ◽  
First Results ◽  
Global Coverage ◽  
The Uk ◽  
Global Navigation Satellite ◽  
Good Visibility

AbstractThe last satellite of BeiDou Navigation Satellite System with Global Coverage (BDS-3) constellation was successfully launched on June 23rd, 2020, and the entire system began to provide Positioning, Navigation, and Timing (PNT) services worldwide. We evaluated the performance of location services using BDS with a smartphone that can track the Global Navigation Satellite System (GNSS) satellites in Nottingham, UK. The static and kinematic experiments were conducted in an open meadow and a lakeside route covered by trees, respectively. Experimental results show that BDS has good visibility, and its overall signal carrier-to-noise density ratio (C/N0) is comparable to that of Global Positioning System (GPS). The average C/N0 of BDS-3 satellites with elevation angles above 45° on B1 band is the highest among all systems, reaching 40.0 dB·Hz. The noise level of the BDS pseudorange measurements is within 0.5 m, and it has a good consistency among satellites. In the static experiment, the standard deviations of BDS positioning in the east, north and up directions are 1.09, 1.16, and 3.02 m, respectively, and the R95 value of the horizontal position is 2.88 m. In harsh environments, the number of BDS satellites tracked by the smartphone is susceptible to environmental factors. The bias Root Mean Squares (RMS) in the three directions of the whole kinematic positioning are 6.83, 6.68, 11.67 m, in which the positioning bias RMS values in a semi-open environment are only 2.81, 1.11, 3.29 m. Furthermore, the inclusion of BDS in multiple GNSS systems can significantly improve the positioning precision. This study intends to provide a reference for the further improvements of BDS global PNT services, particularly for Location-Based Services (LBS).

scholarly journals Spaceborne GNSS-R Observation of Global Lake Level: First Results from the TechDemoSat-1 Mission

2019 ◽  
Vol 11 (12) ◽  
pp. 1438 ◽  
Author(s):  
Liwen Xu ◽  
Wei Wan ◽  
Xiuwan Chen ◽  
Siyu Zhu ◽  
Baojian Liu ◽  
...  
Keyword(s):  
Satellite System ◽  
Temporal Variations ◽  
Strong Correlations ◽  
Lake Levels ◽  
The Caspian Sea ◽  
First Results ◽  
The Uk ◽  
Global Navigation Satellite ◽  
Inland Water Bodies ◽  
First Time

Spaceborne global navigation satellite system reflectometry (GNSS-R) data collected by the UK TechDemoSat-1 (TDS-1) satellite is applied to retrieve global lake levels for the first time. Lake levels of 351 global lakes (area greater than 500 km2 and elevation lower than 3000 m each) are estimated using TDS-1 Level 1b data over 2015–2017. Strong correlations (overall R2 greater than 0.95) are observed among lake levels derived from TDS-1 and other altimetry satellites such as CryoSat-2, Jason, and Envisat (the latter two are collected by Hydroweb), although with large root-mean-square error (RMSE) (tens of meters) mainly due to the fact that TDS-1 is not dedicated for altimetry measuring purpose. Examples of the Caspian Sea and the Poyang Lake show consistent spatial and temporal variations between TDS-1 and other data sources. The results in this paper provide supportive information for further application of GNSS-R constellations to measure altimetry of inland water bodies.

scholarly journals PAU/GNSS-R: Implementation, Performance and First Results of a Real-Time Delay-Doppler Map Reflectometer Using Global Navigation Satellite System Signals

Sensors ◽  
2008 ◽  
Vol 8 (5) ◽  
pp. 3005-3019 ◽  
Author(s):  
Juan Marchan-Hernandez ◽  
Adriano Camps ◽  
Nereida Rodriguez-Alvarez ◽  
Xavier Bosch-Lluis ◽  
Isaac Ramos-Perez ◽  
...  
Keyword(s):  
Time Delay ◽  
Real Time ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
First Results ◽  
Global Navigation ◽  
Global Navigation Satellite

scholarly journals Maritime Multiple Moving Target Detection Using Multiple-BDS-Based Radar: Doppler Phase Compensation and Resolution Improvement

2021 ◽  
Vol 13 (24) ◽  
pp. 4963
Author(s):  
Xiang Lan ◽  
Liuying Wang ◽  
Jinxing Li ◽  
Wangqiang Jiang ◽  
Min Zhang
Keyword(s):  
Satellite System ◽  
Mimo Radar ◽  
Navigation Satellite ◽  
Multiple Sources ◽  
Radar Systems ◽  
Multiple Input ◽  
Gnss Reflectometry ◽  
Global Coverage ◽  
Global Navigation Satellite ◽  
Multiple Moving Targets

With the realization of global navigation satellite system (GNSS) completion, GNSS reflectometry (GNSS-R) has become increasingly popular due to the advantages of global coverage and the availability of multiple sources in terms of earth remote sensing. This paper analyzes the Beidou navigation satellite system (BDS) signal reflection detection of multiple satellites and multiple moving targets under multiple-input and multiple-output (MIMO) radar systems and proposes a series of methods to suppress multiple Doppler phase influences and improve the range detection property. The simulation results show the restored target peaks, which match the RCS data more accurately, with the GNSS-R Doppler phase influence removed, which proves the proposed method can improve target recognition and detection resolution performance.

scholarly journals Navigation in GEO, HEO, and Lunar Trajectory Using Multi-GNSS Sidelobe Signals

2022 ◽  
Vol 14 (2) ◽  
pp. 318
Author(s):  
Meiqian Guan ◽  
Tianhe Xu ◽  
Min Li ◽  
Fan Gao ◽  
Dapeng Mu
Keyword(s):  
Control Systems ◽  
Single Point ◽  
Satellite System ◽  
Ground Control ◽  
Navigation Satellite ◽  
Navigation Systems ◽  
Beidou Navigation Satellite System ◽  
Global Coverage ◽  
Global Navigation Satellite ◽  
Ranging Errors

Positioning of spacecraft (e.g., geostationary orbit (GEO), high elliptical orbit (HEO), and lunar trajectory) is crucial for mission completion. Instead of using ground control systems, global navigation satellite system (GNSS) can be an effective approach to provide positioning, navigation and timing service for spacecraft. In 2020, China finished the construction of the third generation of BeiDou navigation satellite system (BDS-3); this global coverage system will contribute better sidelobe signal visibility for spacecraft. Meanwhile, with more than 100 GNSS satellites, multi-GNSS navigation performance on the spacecraft is worth studying. In this paper, instead of using signal-in-space ranging errors, we simulate pseudorange observations with measurement noises varying with received signal powers. Navigation performances of BDS-3 and its combinations with other systems were conducted. Results showed that, owing to GEO and inclined geosynchronous orbit (IGSO) satellites, all three types (GEO, HEO, and lunar trajectory) of spacecraft received more signals from BDS-3 than from other navigation systems. Single point positioning (SPP) accuracy of the GEO and HEO spacecraft was 17.7 and 23.1 m, respectively, with BDS-3 data alone. Including the other three systems, i.e., GPS, Galileo, and GLONASS, improved the SPP accuracy by 36.2% and 19.9% for GEO and HEO, respectively. Navigation performance of the lunar probe was significantly improved when receiver sensitivity increased from 20 dB-Hz to 15 dB-Hz. Only dual- (BDS-3/GPS) or multi-GNSS (BDS-3, GPS, Galileo, GLONASS) could provide continuous navigation solutions with a receiver threshold of 15 dB-Hz.

Preliminary Results of GNSS Radio Occultation Receiver onboard CSES

2020 ◽  
Author(s):  
Song Xu ◽  
ZhiMa ZeRen ◽  
JiangPing Huang ◽  
XuHui Shen ◽  
Wei Chu ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Low Cost ◽  
Satellite System ◽  
Navigation Satellite ◽  
Global Positioning ◽  
High Vertical Resolution ◽  
Global Coverage ◽  
Global Navigation Satellite ◽  
Ionospheric Characteristic

<p>The China Seismo-Electromagnetic Satellite (CSES) was successfully launched on February 2, 2018. Its main scientific objective is to monitor earthquake related disturbances in the ionosphere. The Global Navigation Satellite System (GNSS) Radio Occultation Receiver (GOR) on board the satellite is able to observe the occultation events of Global Positioning System (GPS) and BeiDou navigation satellite System(BDS). Compared to some conventional observation means, GOR has the advantages of low cost, high accuracy, high precision, high vertical resolution, all-weather sounding, long-term constant and global coverage. The GOR on CSES can receive about 600 ionosphere occultation events each day and 16000 each month. The strip-shaped spatial distributions of the ionospheric characteristic parameters from the GOR show that the values of NmF<sub>2</sub> and HmF<sub>2</sub> are larger in the areas of the equator than in middle and high latitude areas.</p>

scholarly journals Satellite Navigation for Digital Earth

2019 ◽  
pp. 125-160
Author(s):  
Chuang Shi ◽  
Na Wei
Keyword(s):  
Satellite Orbit ◽  
Satellite System ◽  
Location Based Services ◽  
Global Navigation Satellite Systems ◽  
System Structure ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Digital Earth ◽  
Wide Area Augmentation System ◽  
Global Navigation Satellite

Abstract Global navigation satellite systems (GNSSs) have been widely used in navigation, positioning, and timing. China’s BeiDou Navigation Satellite System (BDS) would reach full operational capability with 24 Medium Earth Orbit (MEO), 3 Geosynchronous Equatorial Orbit (GEO) and 3 Inclined Geosynchronous Satellite Orbit (IGSO) satellites by 2020 and would be an important technology for the construction of Digital Earth. This chapter overviews the system structure, signals and service performance of BDS, Global Positioning System (GPS), Navigatsionnaya Sputnikovaya Sistema (GLONASS) and Galileo Navigation Satellite System (Galileo) system. Using a single GNSS, positions with an error of ~ 10 m can be obtained. To enhance the positioning accuracy, various differential techniques have been developed, and GNSS augmentation systems have been established. The typical augmentation systems, e.g., the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the global differential GPS (GDGPS) system, are introduced in detail. The applications of GNSS technology and augmentation systems for space-time geodetic datum, high-precision positioning and location-based services (LBS) are summarized, providing a reference for GNSS engineers and users.

scholarly journals Characteristics of receiver-related biases between BDS-3 and BDS-2 for five frequencies including inter-system biases, differential code biases, and differential phase biases

GPS Solutions ◽  
2021 ◽  
Vol 25 (3) ◽  
Author(s):  
Xiaolong Mi ◽  
Chuanzhen Sheng ◽  
Ahmed El-Mowafy ◽  
Baocheng Zhang
Keyword(s):  
Satellite System ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Test Results ◽  
Satellite Systems ◽  
Differential Phase ◽  
Differential Code Biases ◽  
Global Coverage ◽  
The One ◽  
Global Navigation Satellite

AbstractIt is foreseeable that the BeiDou navigation satellite system with global coverage (BDS-3) and the BeiDou navigation satellite (regional) system (BDS-2) will coexist in the next decade. Care should be taken to minimize the adverse impact of the receiver-related biases, including inter-system biases (ISBs), differential code biases (DCB), and differential phase biases (DPB) on the positioning, navigation, and timing (PNT) provided by global navigation satellite systems (GNSS). Therefore, it is important to ascertain the intrinsic characteristics of receiver-related biases, especially in the context of the combination of BDS-3 and BDS-2, which have some differences in their signal level. We present a method that enables time-wise retrieval of between-receiver ISBs, DCB, and DPB from multi-frequency multi-GNSS observations. With this method, the time-wise estimates of the receiver-related biases between BDS-3 and BDS-2 are determined using all five frequencies available in different receiver pairs. Three major findings are suggested based on our test results. First, code ISBs are significant on the two overlapping frequencies B1II and B2b/B2I between BDS-3 and BDS-2 for a baseline with non-identical receiver pairs, which disrupts the compatibility of the two constellations. Second, epoch-wise DCB estimates of the same type in BDS-3 and BDS-2 can show noticeable differences. Thus, it is unreasonable to treat them as one constellation in PNT applications. Third, the DPB of BDS-3 and BDS-2 may have significant short-term variations, which can be attributed to, on the one hand, receivers composing baselines, and on the other hand, frequencies.

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.

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