Article
Environmental Sciences
Hengyang Guo, Jinyun Guo, Zhouming Yang, Guangzhe Wang, Linhu Qi, Mingsen Lin, Hailong Peng, Bing Ji
Summary: The Haiyang-2C (HY-2C) satellite, equipped with the independently developed HY2_Receiver onboard, was launched by China for marine monitoring purposes. Evaluations of the receiver performance led to successful precise orbit determination (POD) missions using satellite-borne GPS data. The study also proposed a new method for validating the accuracy of the HY-2C RD orbit using DORIS data, resulting in a range rate accuracy of within 0.0063 m/s.
Article
Engineering, Aerospace
Patrick Schreiner, Rolf Koenig, Karl Hans Neumayer, Anton Reinhold
Summary: The Helmholtz-Zentrum Potsdam GFZ German Research Centre for Geosciences is involved in the reprocessing of satellite data to improve the accuracy of global positioning systems. By combining multiple observation techniques, they were able to determine the reference frame for satellite orbits and evaluate the precision of the measurements. The results showed that using GPS in combination with other techniques significantly improved the accuracy of the orbits, particularly in the transverse and normal directions.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Remote Sensing
Xingyu Zhou, Hua Chen, Wenlan Fan, Xiaohui Zhou, Qusen Chen, Weiping Jiang
Summary: The study compares the performance of Single-difference Ambiguity Resolution (SD AR) and Track-to-track Ambiguity Resolution (T2T AR) in precise orbit determination for Low Earth Orbit (LEO) satellites. Results show that SD AR slightly outperforms T2T AR in Reduced Dynamic Precise Orbit Determination (RDPOD) and has a higher success rate in ambiguity resolution.
Article
Engineering, Aerospace
Mingming Liu, Yunbin Yuan, Jikun Ou, Guanglin Yang
Summary: The FY3C and FY3D satellites used global navigation satellite occultation detector (GNOS) receivers to receive GPS and BDS-2 signals. In order to improve precise orbit determination (POD) precisions, the variations in receiver GPS and BDS signal phase centers were estimated, and different weights were assigned to GPS and BDS-2 observations in the combined POD. The BDS-based POD precision using BDS-2 satellite antenna phase center offset (PCO) values from the China Satellite Navigation Office (CSNO) is less accurate compared to values obtained from the International GNSS Service (IGS) Multi-GNSS experiments project (MGEX).
ADVANCES IN SPACE RESEARCH
(2023)
Article
Geochemistry & Geophysics
Oliver Montenbruck, Stefan Hackel, Martin Wermuth, Franz Zangerl
Summary: The Sentinel-6 (or Jason-CS) altimetry mission extends previous missions for ocean surface topography monitoring, requiring highly accurate knowledge of orbital position. The Sentinel-6A spacecraft uses a dual-constellation GNSS receiver for precise orbit determination and achieves 1 cm consistency in solutions. Galileo measurements exhibit smaller errors than GPS, but the POD benefits from the increased number of satellites in the combined solution, ultimately meeting mission needs for RMS height errors of less than 1.5 cm.
JOURNAL OF GEODESY
(2021)
Article
Environmental Sciences
Rui Zhang, Yongliang Xiong, Shaoguang Xu, Weiwei Chen, Xinzhong Li, Ban Zhao
Summary: The Swarm mission aims to study the principle and change regularities of the Earth's magnetic field. This article focuses on improving the accuracy of Swarm kinematic orbit determination using two different double-difference methods. The results show that the accuracy of the kinematic orbit determination is at the centimeter level.
Article
Engineering, Multidisciplinary
Min Li, Kai Wei, Tianhe Xu, Yali Shi, Dixing Wang
Summary: Due to the limitations of ground monitoring stations in China for the BDS, the accuracy of BDS Medium Earth Orbit (MEO) satellite orbits can be influenced. To overcome this, low Earth orbit (LEO) satellites can be used as additional monitoring stations. In this study, data from two LEO satellites were collected to improve the precise orbit determination of the BDS. By comparing the results with GPS and BDS-2/3 solutions, it was found that including the LEO satellites significantly improved the accuracy of GPS and BDS-2/3 orbits.
Article
Engineering, Electrical & Electronic
Ruizhi Chen, Zheng Li, Feng Ye, Guangyi Guo, Shihao Xu, Long Qian, Zuoya Liu, Lixiong Huang
Summary: This article introduces an indoor positioning system based on acoustic ranging signals, which provides accurate positioning for smartphones in both static and dynamic cases. The system utilizes a two-stage algorithm for signal detection and integration, achieving a mean error of about 0.3-1 m in ranging estimation and a static positioning accuracy of better than 0.5 m. In dynamic tests, positioning accuracy of 0.5 m at 50% and 1.6 m at 95% is achieved with four anchors in the first scene, and 0.5 m at 50% and 1.82 m at 95% with eight anchors in the second scene.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Environmental Sciences
Zicong An, Kai Shao, Defeng Gu, Chunbo Wei, Zheyu Xu, Lisheng Tong, Jubo Zhu, Jian Wang, Daoping Liu
Summary: Satellite laser ranging (SLR) is a precise space geodetic technique for measuring distances with millimeter-level accuracy. This study investigates the accuracy of precise orbit determination (POD) for BeiDou Navigation-3 (BDS-3) satellites using SLR data and explores the factors influencing the accuracy. Actual SLR data showed that the POD accuracy was positively correlated with the orbital arc lengths. The impact of SLR observations, stations, measurement errors, and orbit modeling errors on the POD accuracy was also analyzed. The results provide valuable insights for improving the precision of satellite orbit determination using SLR data.
Article
Geochemistry & Geophysics
Xingyu Zhou, Hua Chen, Weiping Jiang, Yan Chen, Taoyong Jin, Tianjun Liu, Yang Gao
Summary: A new AR method called SDT2T is proposed in this study, which can greatly eliminate GNSS and receiver biases without external knowledge, and shows improvements comparable to traditional SD AR.
JOURNAL OF GEODESY
(2022)
Article
Remote Sensing
Grzegorz Bury, Krzysztof Sosnica, Radoslaw Zajdel, Dariusz Strugarek
Summary: This study examines the impact of different models on GLONASS satellite orbit determination and finds that the introduction of the box-wing model significantly improves the accuracy of GLONASS orbits, especially for GLONASS-K satellites. Additionally, the use of satellite laser ranging observations further improves the orbit determination results.
Article
Engineering, Multidisciplinary
Razieh Darang, Saeed Nasri, Mansoor Zeinali
Summary: This paper presents an iterative approach to minimize phase difference error in interferometric synthetic aperture radar (InSAR) systems. The proposed method describes the interferometric phase relationships, formulates the phase unwrapping problem as an optimization issue, and converts the cost function into a submodular convex Markov random field function. Numerical studies confirm the efficiency and superiority of the proposed method in terms of elevation estimation.
Article
Engineering, Multidisciplinary
Tian Zeng, Lifen Sui, Rengui Ruan, Xiaolin Jia, Laiping Feng, Guorui Xiao
Summary: The study of a triple-frequency uncombined POD method for GNSS satellites shows that using the third frequency signal leads to more robust results and improvements in orbit and clock accuracy compared to the dual-frequency ionosphere-free linear combination POD method.
Article
Remote Sensing
Kan Wang, Ahmed El-Mowafy, Chris Rizos
Summary: Due to the increasing requirement for high accuracy orbital information for LEO satellites, this contribution investigates the integrity monitoring (IM) strategy for precise orbit determination (POD) in both kinematic and reduced-dynamic modes. The test results show that the average-case mean protection levels (PLs) can be significantly reduced from about 3-4 m in kinematic mode to about 1 m in reduced-dynamic mode, benefiting from the dynamic models used and improved model strength.
Article
Engineering, Aerospace
Javier Berzosa-Molina, Heike Peter, Jaime Fernandez, Pierre Femenias
Summary: The Copernicus Sentinel-3B satellite, launched in April 2018, is being flown in tandem with Sentinel-3A for calibration, validation of instruments, and GPS receiver testing. The performance of the new L2C signal and the accuracy of satellite orbits are analyzed, showing results comparable to operational orbit products.
ADVANCES IN SPACE RESEARCH
(2021)
Article
Remote Sensing
Oliver Montenbruck, Belen Gonzalez Rodriguez
Article
Engineering, Aerospace
Oliver Montenbruck, Peter Steigenberger, Moritz Aicher
Summary: GNSS positioning relies on predicted orbit and clock information transmitted by satellites. A tailored force model for numerical orbit propagation has been proposed for high accuracy in real-time environments. Using the Galileo constellation as an example, global average signal-in-space range errors and 3D position errors are demonstrated to be small after two-week predictions, showing the capability for rapid first fix or contingency navigation without ground updates.
NAVIGATION-JOURNAL OF THE INSTITUTE OF NAVIGATION
(2021)
Article
Remote Sensing
Lucas Schreiter, Oliver Montenbruck, Franz Zangerl, Christian Siemes, Daniel Arnold, Adrian Jaeggi
Summary: This study utilizes GPS tracking data from Swarm satellites to explore gravity fields, revealing anomalies near the geomagnetic equator. An analytical correction method is developed to reduce errors and anomalies, but is not as effective as the down-weighting approach used in earlier studies. However, the analytical correction allows for more kinematic positions to be retained in heavily disturbed months and provides stronger signals for gravity field estimation in equatorial regions.
Article
Remote Sensing
Luca Carlin, Andre Hauschild, Oliver Montenbruck
Summary: PPP technique has been well-established in navigation for more than 20 years, and using broadcast ephemerides and observations of Galileo and GPS can improve positioning accuracy. The dual-constellation solution can enhance accuracy while compensating for SISRE, leading to significant performance improvement.
Article
Engineering, Aerospace
Andre Hauschild, Oliver Montenbruck
Summary: The study demonstrates that using dual-frequency observations and broadcast ephemerides from GPS, Galileo, and BeiDou-3 can significantly reduce orbit errors and achieve satellite navigation accuracy of about one decimeter.
NAVIGATION-JOURNAL OF THE INSTITUTE OF NAVIGATION
(2021)
Article
Geochemistry & Geophysics
Oliver Montenbruck, Stefan Hackel, Martin Wermuth, Franz Zangerl
Summary: The Sentinel-6 (or Jason-CS) altimetry mission extends previous missions for ocean surface topography monitoring, requiring highly accurate knowledge of orbital position. The Sentinel-6A spacecraft uses a dual-constellation GNSS receiver for precise orbit determination and achieves 1 cm consistency in solutions. Galileo measurements exhibit smaller errors than GPS, but the POD benefits from the increased number of satellites in the combined solution, ultimately meeting mission needs for RMS height errors of less than 1.5 cm.
JOURNAL OF GEODESY
(2021)
Article
Remote Sensing
Peter Steigenberger, Oliver Montenbruck, Markus Bradke, Markus Ramatschi, Uwe Hessels
Summary: This paragraph describes the earth rotation parameters in modern navigation messages and how global navigation satellite systems obtain and use these parameters. The data shows some differences between different systems, but for spacecraft navigation, the broadcast ERP accuracy of GPS, QZSS, and IRNSS is sufficient to support autonomous navigation.
Article
Remote Sensing
Oliver Montenbruck, Florian Kunzi, Andre Hauschild
Summary: The feasibility of precise real-time orbit determination using onboard GNSS observations is evaluated based on six months of flight data from the Sentinel-6A mission. The study shows that with the use of dual-constellation pseudorange and carrier phase measurements, as well as broadcast ephemerides, navigation solutions with a representative position error of 10 cm can be achieved. The study highlights the superior performance of Galileo broadcast ephemerides, which enable geodetic-grade GNSS real-time orbit determination without the need for external correction services.
Article
Remote Sensing
Andre Hauschild, Oliver Montenbruck, Peter Steigenberger, Ilaria Martini, Ignacio Fernandez-Hernandez
Summary: The High Accuracy Service (HAS) is a new addition to the Galileo service portfolio that provides free correction data for precise point positioning in real-time. Through testing with the Sentinel-6A LEO satellite, it has been found that using HAS corrections can significantly improve positioning accuracy.
Article
Remote Sensing
Luca Carlin, Oliver Montenbruck, Johann Furthner, Andre Hauschild
Summary: This study discusses the use of precise point positioning with broadcast ephemerides (PPP-BCE) as an alternative to the established all-in-view technique for multi-GNSS time transfer. The method combines broadcast ephemerides with low-noise carrier-phase observations to improve the precision of GNSS system time scales and Coordinated Universal Time (UTC). It can be applied to stationary and mobile receivers in offline or real-time analyses.
Article
Geochemistry & Geophysics
Oliver Montenbruck, Peter Steigenberger, Arturo Villiger, Paul Rebischung
Summary: Phase center offsets of GNSS transmit antennas affect the scale of the terrestrial reference frame, and changes in the reference frame scale require corrections to the antenna offsets. A semi-analytical model is developed to determine the relation between the offsets and scale for different GNSSs.
JOURNAL OF GEODESY
(2022)
Article
Remote Sensing
O. Montenbruck, P. Steigenberger, J. M. Sleewaegen
Summary: The study evaluates the pilot channel biases for different modern signals of GPS, Galileo, BeiDou-3, and QZSS constellations. The results show that the biases range from about 2ns for GPS L5 signal to less than 0.1-0.3ns for Galileo E1 and E5a/b signals. These findings are expected to improve the generation of satellite clock and bias products by the International GNSS Service and enable consistent use by multi-GNSS users.
Article
Remote Sensing
J. M. Sleewaegen, O. Montenbruck, P. Steigenberger
Summary: The analysis of the bias between QZSS L5-Q and L5-I pseudoranges reveals decimeter-level variations over the satellite passes, which is not observed in any other GNSS signal. The study shows that the bias depends on the orientation of the line-of-sight vector with respect to the transmit antenna panel of the QZSS satellite and its amplitude is satellite dependent. The cause of the bias is identified as interference from the L5S signal transmitted by QZSS satellites at the same frequency, introducing a distortion that affects pseudoranges produced using the pilot signal component.
Article
Geochemistry & Geophysics
P. Steigenberger, O. Montenbruck
Summary: Information on satellite antenna phase center offsets (PCOs) is crucial for high-precision applications of global navigation satellite systems. Pre-flight manufacturer calibrations of the PCOs are available for all individual Galileo satellites and each frequency. The consistency of the PCO values for different frequencies becomes increasingly important due to the growing number of E5b and E6-capable receivers and upcoming multi-frequency applications.
JOURNAL OF GEODESY
(2023)
Article
Geochemistry & Geophysics
Bingbing Duan, Urs Hugentobler, Oliver Montenbruck, Peter Steigenberger
Summary: Each Galileo satellite provides coherent navigation signals in four frequency bands. This study evaluates the quality of Galileo satellite products determined by using different dual-frequency and multi-frequency measurements based on different ground networks. The results show that the orbit precision determined from E1/E6 dual-frequency measurements is worse than that from other dual-frequency solutions. Multi-frequency measurements have advantages over dual-frequency for precise orbit determination, especially in small networks. Satellite phase bias products determined from a 20-station network are precise enough for precise point positioning applications with ambiguity resolution.
JOURNAL OF GEODESY
(2023)
