Journal articles on the topic 'GNSS data'
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1
Yang, Guanglin, Weihua Bai, Jinsong Wang, Xiuqing Hu, Peng Zhang, Yueqiang Sun, Na Xu, et al. "FY3E GNOS II GNSS Reflectometry: Mission Review and First Results." Remote Sensing 14, no. 4 (February 17, 2022): 988. http://dx.doi.org/10.3390/rs14040988.
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FengYun-3E (FY3E), launched on 5 July 2021, is one of China’s polar-orbiting meteorological satellite series. The GNOS II onboard FY3E is an operational GNSS remote sensor that for the first time combines GNSS radio occultation (GNSS RO) and GNSS reflectometry (GNSS-R). It has eight reflection channels that can track eight specular points at the same time, receiving reflected signals from multiple GNSS systems, including GPS, BeiDou and Galileo. The basic GNSS-R output generated by GNOS II is a 122 × 20 non-uniform delay-Doppler map whose high resolution portion captures more information near the specular point. This paper introduces the GNSS-R aspect of the FengYun-3E GNOS II, including the instrument, power calibration and wind speed retrieval algorithm. Preliminary validation results for its first four months of data are also presented. After preliminary quality control, the overall wind speed error is less than 2 m/s at wind speeds below 20 m/s for data from both GPS satellites and BeiDou satellites when compared to the ECMWF reanalysis winds.
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Gu, Nianzu, Fei Xing, and Zheng You. "GNSS Spoofing Detection Based on Coupled Visual/Inertial/GNSS Navigation System." Sensors 21, no. 20 (October 12, 2021): 6769. http://dx.doi.org/10.3390/s21206769.
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Spoofing attacks are one of the severest threats for global navigation satellite systems (GNSSs). This kind of attack can damage the navigation systems of unmanned air vehicles (UAVs) and other unmanned vehicles (UVs), which are highly dependent on GNSSs. A novel method for GNSS spoofing detection based on a coupled visual/inertial/GNSS positioning algorithm is proposed in this paper. Visual inertial odometry (VIO) has high accuracy for state estimation in the short term and is a good supplement for GNSSs. Coupled VIO/GNSS navigation systems are, unfortunately, also vulnerable when the GNSS is subject to spoofing attacks. The method proposed in this article involves monitoring the deviation between the VIO and GNSS under an optimization framework. A modified Chi-square test triggers the spoofing alarm when the detection factors become abnormal. After spoofing detection, the optimal estimation algorithm is modified to prevent it being deceived by the spoofed GNSS data and to enable it to carry on positioning. The performance of the proposed spoofing detection method is evaluated through a real-world visual/inertial/GNSS dataset and a real GNSS spoofing attack experiment. The results indicate that the proposed method works well even when the deviation caused by spoofing is small, which proves the efficiency of the method.
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Xu, Changhui, Jingkui Zhang, Zhiyou Zhang, Jianning Hou, and Xujie Wen. "Data and Service Security of GNSS Sensors Integrated with Cryptographic Module." Micromachines 14, no. 2 (February 15, 2023): 454. http://dx.doi.org/10.3390/mi14020454.
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Navigation and positioning are of increasing importance because they are becoming a new form of infrastructure. To ensure both development and security, this study designed a technical innovation structure to upgrade the GNSS (Global Navigation Satellite System) data transmission and real-time differential correction service system and proposed a new multiple cryptographic fusion algorithm to achieve the encryption and decryption of GNSS data and services. First, a GNSS station encrypts GNSS data with an encryption key and obtains a public key from a GNSS data center to encrypt the GNSS data encryption key. After that, identity authentication of a GNSS station is carried out, and an SSL VPN is established between the GNSS station and a GNSS data center before GNSS data are transmitted to the GNSS data center. Then, the GNSS data center decrypts the received GNSS data. The process of an intelligent terminal for real-time differential corrections is similar to that of the GNSS station and the GNSS data center. A GNSS sensor integrated with a cryptographic module was developed to validate the structure in an open environment. The results showed that the developed GNSS sensor was successful in encrypting the data, and the GNSS data center was able to decrypt the data correctly. For the performance test, a cryptography server was able support the requirements of GNSS applications. However, a cryptography server was optimal in supporting 40~50 GNSS stations simultaneously, whereas a cluster was suggested to be configured if the number of GNSS stations was more than 60. In conclusion, the method was able to ensure the validity, confidentiality, integrity, and non-repudiation of GNSS data and services. The proposed upgrading technology was suitable for coordinating GNSS development and security.
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Zhao, Qingzhi, Kefei Zhang, and Wanqiang Yao. "Influence of station density and multi-constellation GNSS observations on troposphere tomography." Annales Geophysicae 37, no. 1 (January 14, 2019): 15–24. http://dx.doi.org/10.5194/angeo-37-15-2019.
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Abstract. Troposphere tomography, using multi-constellation observations from global navigation satellite systems (GNSSs), has become a novel approach for the three-dimensional (3-D) reconstruction of water vapour fields. An analysis of the integration of four GNSSs (BeiDou, GPS, GLONASS, and Galileo) observations is presented to investigate the impact of station density and single- and multi-constellation GNSS observations on troposphere tomography. Additionally, the optimal horizontal resolution of the research area is determined in Hong Kong considering both the number of voxels divided, and the coverage rate of discretized voxels penetrated by satellite signals. The results show that densification of the GNSS network plays a more important role than using multi-constellation GNSS observations in improving the retrieval of 3-D atmospheric water vapour profiles. The root mean square of slant wet delay (SWD) residuals derived from the single-GNSS observations decreased by 16 % when the data from the other four stations are added. Furthermore, additional experiments have been carried out to analyse the contributions of different combined GNSS data to the reconstructed results, and the comparisons show some interesting results: (1) the number of iterations used in determining the weighting matrices of different equations in tomography modelling can be decreased when considering multi-constellation GNSS observations and (2) the reconstructed quality of 3-D atmospheric water vapour using multi-constellation GNSS data can be improved by about 11 % when compared to the SWD estimated with precise point positioning, but this was not as high as expected.
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Bai, Weihua, Guojun Wang, Yueqiang Sun, Jiankui Shi, Guanglin Yang, Xiangguang Meng, Dongwei Wang, et al. "Application of the Fengyun 3 C GNSS occultation sounder for assessing the global ionospheric response to a magnetic storm event." Atmospheric Measurement Techniques 12, no. 3 (March 7, 2019): 1483–93. http://dx.doi.org/10.5194/amt-12-1483-2019.
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Abstract. The rapid advancement of global navigation satellite system (GNSS) occultation technology in recent years has made it one of the most advanced space-based remote sensing technologies of the 21st century. GNSS radio occultation has many advantages, including all-weather operation, global coverage, high vertical resolution, high precision, long-term stability, and self-calibration. Data products from GNSS occultation sounding can greatly enhance ionospheric observations and contribute to space weather monitoring, forecasting, modeling, and research. In this study, GNSS occultation sounder (GNOS) results from a radio occultation sounding payload aboard the Fengyun 3 C (FY3-C) satellite were compared with ground-based ionosonde observations. Correlation coefficients for peak electron density (NmF2) derived from GNOS Global Position System (GPS) and Beidou navigation system (BDS) products with ionosonde data were higher than 0.9, and standard deviations were less than 20 %. Global ionospheric effects of the strong magnetic storm event in March 2015 were analyzed using GNOS results supported by ionosonde observations. The magnetic storm caused a significant disturbance in NmF2 level. Suppressed daytime and nighttime NmF2 levels indicated mainly negative storm conditions. In two longitude section zones of geomagnetic inclination between 40 and 80∘, the results of average NmF2 observed by GNOS and ground-based ionosondes showed the same basic trends during the geomagnetic storm and confirmed the negative effect of this storm event on the ionosphere. The analysis demonstrates the reliability of the GNSS radio occultation sounding instrument GNOS aboard the FY3-C satellite and confirms the utility of ionosphere products from GNOS for statistical and event-specific ionospheric physical analyses. Future FY3 series satellites and increasing numbers of Beidou navigation satellites will provide increasing GNOS occultation data on the ionosphere, which will contribute to ionosphere research and forecasting applications.
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Sun, Yueqiang, Weihua Bai, Congliang Liu, Yan Liu, Qifei Du, Xianyi Wang, Guanglin Yang, et al. "The FengYun-3C radio occultation sounder GNOS: a review of the mission and its early results and science applications." Atmospheric Measurement Techniques 11, no. 10 (October 23, 2018): 5797–811. http://dx.doi.org/10.5194/amt-11-5797-2018.
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Abstract. The Global Navigation Satellite System (GNSS) Occultation Sounder (GNOS) is one of the new-generation payloads on board the Chinese FengYun 3 (FY-3) series of operational meteorological satellites for sounding the Earth's neutral atmosphere and ionosphere. FY-3C GNOS, on board the FY-3 series C satellite launched in September 2013, was designed to acquire setting and rising radio occultation (RO) data by using GNSS signals from both the Chinese BeiDou Navigation Satellite System (BDS) and the US Global Positioning System (GPS). So far, the GNOS measurements and atmospheric and ionospheric data products have been validated and evaluated and then been used for atmosphere- and ionosphere-related scientific applications. This paper reviews the FY-3C GNOS instrument, RO data processing, data quality evaluation, and preliminary research applications according to the state-of-the-art status of the FY-3C GNOS mission and related publications. The reviewed data validation and application results demonstrate that the FY-3C GNOS mission can provide accurate and precise atmospheric and ionospheric GNSS (i.e., GPS and BDS) RO profiles for numerical weather prediction (NWP), global climate monitoring (GCM), and space weather research (SWR). The performance of the FY-3C GNOS product quality evaluation and scientific applications establishes confidence that the GNOS data from the series of FY-3 satellites will provide important contributions to NWP, GCM, and SWR scientific communities.
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Guerova, G., T. Simeonov, and N. Yordanova. "The Sofia University Atmospheric Data Archive (SUADA)." Atmospheric Measurement Techniques 7, no. 8 (August 21, 2014): 2683–94. http://dx.doi.org/10.5194/amt-7-2683-2014.
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Abstract. Atmospheric sounding using the Global Navigation Satellite Systems (GNSS) is a well-established research field in Europe. At present, GNSS data from 1800 stations are available for model validation and assimilation in state-of-the-art models used for operational numerical weather prediction centres in Europe. Advances in GNSS data processing make it possible also to use the GNSS data for climatic trend analysis, an emerging new application. In Bulgaria and southeastern Europe, the use of GNSS for atmospheric sounding is currently under development. As a first step, the Sofia University Atmospheric Data Archive (SUADA) is developed. SUADA is a user-friendly database, and includes GNSS tropospheric products like zenith total delay (ZTD) and derivatives like vertically integrated water vapour (IWV), as well as observations from radiosonde (RS) and surface atmospheric data. Archived in SUADA are (1) GNSS tropospheric products (over 12 000 000 individual observations) and derivatives (over 55 000) from five GNSS processing strategies and 37 stations for the period 1997–2013, with temporal resolutions from 5 min to 6 h, and (2) radiosonde IWV data (over 6000 observations) for station Sofia (1999–2012). Presented are two applications of the SUADA data for the study of long- and short-term variations of IWV over Bulgaria during the 2007 heatwave and intense precipitation events in 2012.
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Guerova, G., Tzv Simeonov, and N. Yordanova. "The Sofia University Atmospheric Data Archive (SUADA)." Atmospheric Measurement Techniques Discussions 7, no. 3 (March 5, 2014): 2153–85. http://dx.doi.org/10.5194/amtd-7-2153-2014.
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Abstract. Atmospheric sounding using the Global Navigation Satellite Systems (GNSS) is a well established research field in Europe. At present, GNSS data from 1800 stations are available for model validation and assimilation in state-of-the-art models used for operational numerical weather prediction Centers in Europe. Advances in GNSS data processing is making possible to also use the GNSS data for climatic trend analysis, an emerging new application. In Bulgaria and Southeast Europe the use of GNSS for atmospheric sounding is currently under development. As a first step the Sofia University Atmospheric Data Archive (SUADA) is developed. SUADA is user friendly database and includes GNSS tropospheric products like Zenith Total Delay (ZTD) and derivatives like vertically Integrated Water Vapour (IWV) as well as observations from Radiosonde and surface atmospheric data. Archived in SUADA are: (1) GNSS tropospheric products (over 12 000 000 individual observations) and derivatives (over 55 000) from five GNSS processing strategies and 37 stations for the period 1997–2013 with temporal resolution from 5 min to 6 h and (2) Radiosonde IWV data (over 6000 observations) for station Sofia (1999–2012). Presented are two applications of the SUADA data for study of long and short term variation of IWV over Bulgaria during the 2007 heat wave and intense precipitation events in 2012.
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Rovira-Garcia, Adria, and José Miguel Juan Zornoza. "Special Issue on GNSS Data Processing and Navigation." Sensors 20, no. 15 (July 24, 2020): 4119. http://dx.doi.org/10.3390/s20154119.
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Global Navigation Satellite System (GNSS) data can be used in a myriad of ways. The current number of applications exceed by far those originally GNSS was designed for. As an example, the present Special Issue on GNSS Data Processing and Navigation compiles 14 international contributions covering several aspects of GNSS research. This Editorial summarizes the whole special issue grouping the contributions under four different, but related topics.
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Yin, Cong, Feixiong Huang, Junming Xia, Weihua Bai, Yueqiang Sun, Guanglin Yang, Xiaochun Zhai, et al. "Soil Moisture Retrieval from Multi-GNSS Reflectometry on FY-3E GNOS-II by Land Cover Classification." Remote Sensing 15, no. 4 (February 17, 2023): 1097. http://dx.doi.org/10.3390/rs15041097.
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The reflected GNSS signals at the L-band is significantly advantageous in soil moisture monitoring as they are sensitive to the dielectric properties determined by the volumetric water content of topsoil, and they can penetrate vegetation, except in very dense forests. The Global Navigation satellite system Occultation Sounder (GNOS-II) with a reflectometry technique onboard the Fengyun-3E (FY-3E) satellite, launched on 5 July 2021, is the first mission that can receive reflected Global Navigation Satellite System (GNSS) signals from GPS, BeiDou and Galileo systems. This paper presents the soil moisture retrieval results from the FY-3E GNOS-II mission using 16 months of data. In this study, the reflectivity observations from different GNSS systems were firstly intercalibrated with some differences analyzed. Observations were also corrected by considering vegetation attenuation for 16 different land cover classifications. Finally, an empirical model was constructed for volumetric soil moisture (VSM) estimation, where the reflectivity of GNOS-II was linearly related to the SMAP reference soil moisture for each 36 km ease grid. The overall root-mean-square error of the retrieved soil moisture is 0.049 compared with the SMAP product, and 0.054 compared with the in situ data. The results of the three GNSS systems show similar levels of accuracy. This paper, for the first time, demonstrates the feasibility of global soil moisture retrieval using multiple GNSS signals.
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Huang, Zhenchuan, Shuanggen Jin, Ke Su, and Xu Tang. "Multi-GNSS Precise Point Positioning with UWB Tightly Coupled Integration." Sensors 22, no. 6 (March 14, 2022): 2232. http://dx.doi.org/10.3390/s22062232.
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Global Navigation Satellite Systems (GNSSs) can provide high-precision positioning services, which can be applied to fields including navigation and positioning, autonomous driving, unmanned aerial vehicles and so on. However, GNSS signals are easily disrupted in complex environments, which results in a positioning performance with a significantly inferior accuracy and lengthier convergence time, particularly for the single GNSS system. In this paper, multi-GNSS precise point positioning (PPP) with tightly integrating ultra-wide band (UWB) technology is presented to implement fast and precise navigation and positioning. The validity of the algorithm is evaluated by a set of GNSS and UWB data. The statistics indicate that multi-GNSS/UWB integration can significantly improve positioning performance in terms of the positioning accuracy and convergence time. The improvement of the positioning performance for the GNSS/UWB tightly coupled integration mainly concerns the north and east directions, and to a lesser extent, the vertical direction. Furthermore, the convergence performance of GNSS/UWB solution is analyzed by simulating GNSS signal interruption. The reliability and robustness of GNSS/UWB solution during GNSS signal interruption is verified. The results show that multi-GNSS/UWB solution can significantly improve the accuracy and convergence speed of PPP.
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Liang, Wei, Roland Pail, Xinyu Xu, and Jiancheng Li. "A new method of improving global geopotential models regionally using GNSS/levelling data." Geophysical Journal International 221, no. 1 (February 3, 2020): 542–49. http://dx.doi.org/10.1093/gji/ggaa047.
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SUMMARY In this paper, a new method for regionally improving global geopotential models (GGMs) with global navigation satellite system (GNSS)/levelling data is proposed. In this method, the GNNS/levelling data are at first converted to disturbing potential data with inverse Bruns’ formula. Then the systematic errors in disturbing potential data are removed with a three-parameter correction surface. Afterwards, the disturbing potential data on the Earth's surface are downward continued to the surface of an inner sphere with inverse Poisson's integral equation. Global disturbing potential data on the whole sphere could be achieved with combination of the downward continued data and the GGM-derived data. At last, the final regionally improved geopotential model (RIGM) could be recovered from the disturbing potential data using least-squares method. Four RIGM models for Qingdao (QD) are determined based on four different sets of GNSS/levelling data points to validate the capability of the method. The standard deviation of height anomaly errors of RIGM-QDs are nearly 25 and 30 per cent on average smaller than Earth Gravity Model 2008 (EGM2008) on checkpoints and data points, respectively. This means that the RIGM-QDs fit better to the GNSS/levelling network in this area than EGM2008. The results show that the proposed method is successful at improving GGMs in regional area with regional GNSS/levelling data.
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Li, Weiqiang, Estel Cardellach, Serni Ribó, Santi Oliveras, and Antonio Rius. "Exploration of Multi-Mission Spaceborne GNSS-R Raw IF Data Sets: Processing, Data Products and Potential Applications." Remote Sensing 14, no. 6 (March 10, 2022): 1344. http://dx.doi.org/10.3390/rs14061344.
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Earth reflected Global Navigation Satellite System (GNSS) signals can be received by dedicated orbital receivers for remote sensing and Earth observation (EO) purposes. Different spaceborne missions have been launched during the past years, most of which can only provide the delay-Doppler map (DDM) of the power of the reflected GNSS signals as their main data products. In addition to the power DDM products, some of these missions have collected a large amount of raw intermediate frequency (IF) data, which are the bit streams of raw signal samples recorded after the analog-to-digital converters (ADCs) and prior to any onboard digital processing. The unprocessed nature of these raw IF data provides an unique opportunity to explore the potential of GNSS Reflectometry (GNSS-R) technique for advanced geophysical applications and future spaceborne missions. To facilitate such explorations, the raw IF data sets from different missions have been processed by Institute of Space Sciences (ICE-CSIC, IEEC), and the corresponding data products, i.e., the complex waveform of the reflected signal, have been generated and released through our public open-data server. These complex waveform data products provide the measurements from different GNSS constellations (e.g., GPS, Galileo and BeiDou), and include both the amplitude and carrier phase information of the reflected GNSS signal at higher sampling rate (e.g., 1000 Hz). To demonstrate these advanced features of the data products, different applications, e.g., inland water detection and surface altimetry, are introduced in this paper. By making these complex waveform data products publicly available, new EO capability of the GNSS-R technique can be further explored by the community. Such early explorations are also relevant to ESA’s next GNSS-R mission, HydroGNSS, which will provide similar complex observations operationally and continuously in the future.
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Aziez, Sameir A., Nawar Al-Hemeary, Ahmed Hameed Reja, Tamás Zsedrovits, and György Cserey. "Using KNN Algorithm Predictor for Data Synchronization of Ultra-Tight GNSS/INS Integration." Electronics 10, no. 13 (June 23, 2021): 1513. http://dx.doi.org/10.3390/electronics10131513.
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The INS system’s update rate is faster than that of the GNSS receiver. Additionally, GNSS receiver data may suffer from blocking for a few seconds for different reasons, affecting architecture integrations between GNSS and INS. This paper proposes a novel GNSS data prediction method using the k nearest neighbor (KNN) predictor algorithm to treat data synchronization between the INS sensors and GNSS receiver and overcome those GNSS receiver’s blocking, which may occur for a few seconds. The experimental work was conducted on a flying drone over a minor Hungarian (Mátyásföld, 47.4992 N, 19.1977 E) model airfield. The GNSS data are predicted by four different scenarios: the first is no blocking of data, and the other three have blocking periods of 1, 4, and 8 s, respectively. Ultra-tight architecture integration is used to perform the GNSS/INS integration to deal with the INS sensors’ inaccuracy and their divergence throughout the operation. The results show that using the GNSS/INS integration system yields better positioning data (in three axes (X, Y, and Z)) than using a stand-alone INS system or GNSS without a predictor.
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Ramadhon, Syafril, Wahyu Widiat Miko, and Gian Nugraha. "Perbandingan Ketelitian Posisi Tiga Dimensi dari Perangkat Lunak Pengolahan Data GNSS Komersial." JGISE: Journal of Geospatial Information Science and Engineering 3, no. 2 (November 25, 2020): 106. http://dx.doi.org/10.22146/jgise.58768.
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Pasar receiver GNSS di Indonesia sudah semakin berkembang dan bergerak ke arah positif, yang ditandai dengan penjualan yang semakin meningkat serta semakin beragamnya merk receiver GNSS dan perangkat lunak pengolahan data yang ada di pasaran. Atas dasar banyaknya perangkat lunak pengolahan data GNSS yang beredar di Indonesia, maka rumusan masalah yang dikedepankan dalam penelitian ini adalah apakah setiap perangkat lunak pengolahan data GNSS dapat memberikan hasil koordinat tiga dimensi yang sama dari suatu data pengukuran. Oleh karena itu, penelitian ini bertujuan untuk membandingkan koordinat tiga dimensi hasil survey GNSS menggunakan tiga perangkat lunak pengolahan data GNSS komersial. Metode yang digunakan adalah dengan membandingkan data survey GNSS menggunakan metode relatif diferensial static pada moda radial pada delapan titik pengamatan dengan panjang baseline < 300 m dan lama pengukuran > 30 menit menggunakan tiga perangkat lunak pengolahan data GNSS komersial, yaitu Trimble Business Center (TBC), Leica Geo Office (LGO), dan MAGNET Tools (MT). Hasil penelitian memberikan kesimpulan bahwa terdapat perbedaan hasil pengolahan data pada tiga perangkat lunak pengolahan data GNSS komersial di delapan titik pengamatan dengan perbedaan maksimum kisaran 5 mm pada sumbu northing, 9 mm pada sumbu easting, dan 68 mm pada data tinggi.
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Tu, Jinsheng, Haohan Wei, Rui Zhang, Lei Yang, Jichao Lv, Xiaoming Li, Shihai Nie, Peng Li, Yanxia Wang, and Nan Li. "GNSS-IR Snow Depth Retrieval from Multi-GNSS and Multi-Frequency Data." Remote Sensing 13, no. 21 (October 26, 2021): 4311. http://dx.doi.org/10.3390/rs13214311.
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Global navigation satellite system interferometric reflectometry (GNSS-IR) represents an extra method to detect snow depth for climate research and water cycle managing. However, using a single frequency of GNSS-IR for snow depth retrieval is often found to be challenging when attempting to achieve a high spatial and temporal sensitivity. To evaluate both the capability of the GNSS-IR snow depth retrieved by the multi-GNSS system and multi-frequency from signal-to-noise ratio (SNR) data, the accuracy of snow depth retrieval by different frequency signals from the multi-GNSS system is analyzed, and a joint retrieval is carried out by combining the multi-GNSS system retrieval results. The SNR data of the global positioning system (GPS), global orbit navigation satellite system (GLONASS), Galileo satellite navigation system (Galileo), and BeiDou navigation satellite system (BDS) from the P387 station of the U.S. Plate Boundary Observatory (PBO) are analyzed. A Lomb–Scargle periodogram (LSP) spectrum analysis is used to compare the difference in reflector height between the snow-free and snow surfaces in order to retrieve the snow depth, which is compared with the PBO snow depth. First, the different frequency retrieval results of the multi-GNSS system are analyzed. Then, the retrieval accuracy of the different GNSS systems is analyzed through multi-frequency mean fusion. Finally, the joint retrieval accuracy of the multi-GNSS system is analyzed through mean fusion. The experimental shows that the retrieval results of different frequencies of the multi-GNSS system have a strong correlation with the PBO snow depth, and that the accuracy is better than 10 cm. The multi-frequency mean fusion of different GNSS systems can effectively improve the retrieval accuracy, which is better than 7 cm. The joint retrieval accuracy of the multi-GNSS system is further improved, with a correlation coefficient (R) between the retrieval snow depth and the PBO snow depth of 0.99, and the accuracy is better than 3 cm. Therefore, using multi-GNSS and multi-frequency data to retrieve the snow depth has a good accuracy and feasibility.
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Jia, Zhi Ge, Zhao Sheng Nie, Zheng Song Chen, and Gang Liu. "Analysis and Study on GNSS Data under EHV Transmission Environment by Using TEQC." Applied Mechanics and Materials 475-476 (December 2013): 287–90. http://dx.doi.org/10.4028/www.scientific.net/amm.475-476.287.
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TEQC is a tool which can be commonly used in GNSS data translation, editing, and quality checking, it's widely used in GNSS data preprocessing. This paper has introduced the common syntax and instruction of TEQC when it used in GNSS data processing, also introduced the testing examples of GNSS receiver under three environments: 220KV UHV transmission line environment, 500KV UHV transmission line environment and standard GNSS calibration field, then using TEQC to preprocess and analysis the data. The results showed that: a)The GNSS observation data Efficiency is not effected from radio interference generated by EHV transmission lines; b)Within 25 meters ranges GNSS observation data under EHV transmission line, the multi-path effects (mp1 and mp2 value) significantly exceeded the normal range, and the voltage higher, the multi-path value larger. c)Apart from 50 meters outside EHV transmission line, there is almost no effect about multi-path affects in the high-precision GNSS observation data.
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Goldberg, Dara E., and Kirstie L. Haynie. "Ready for Real Time: Performance of Global Navigation Satellite System in 2019 Mw 7.1 Ridgecrest, California, Rapid Response Products." Seismological Research Letters 93, no. 2A (January 26, 2022): 517–30. http://dx.doi.org/10.1785/0220210278.
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Abstract Global Navigation Satellite Systems (GNSSs) have undergone notable advancement in the last few decades, leading to the availability of a dataset with capabilities well beyond its original intended purpose. The proliferation of high-rate (1 Hz or greater) GNSS receivers in areas of seismological interest now allows for routine consideration of dynamic earthquake ground motions, with centimeter-level displacement accuracy via precise point positioning methods. Real-time (RT) GNSS observations, from stations that are both telemetered and processed to displacement with minimal latency, have lower accuracy compared to post-processed (PP) GNSS displacements due to imprecise knowledge of atmospheric conditions, satellite clocks, and satellite orbits in RT. Whether the quality of RT high-rate GNSS is sufficient for use in rapid response products remains to be thoroughly examined. Here, we highlight RT GNSS displacement time series processed during the 2019 Mw 7.1 Ridgecrest, California, earthquake in the context of common rapid-response products, magnitude estimation, and kinematic fault-slip models. We discuss how these data can be used to supplement RT seismic data for rapid characterization of significant earthquakes. We find that kinematic fault-slip models using RT GNSS data retain the general spatiotemporal characteristics of those with PP data, with subtle differences in size and amplitude of modeled slip asperities. We demonstrate the effect of these rapid seismic source models using RT GNSS data on the U.S. Geological Survey product ShakeMap—a downstream ground-motion prediction algorithm informed by the rupture dimensions estimated in the slip model. Discrepancies in the ShakeMap estimate are minor, within ±12% change, with the most severe variation at the fault edges. Our analysis suggests that, when used in conjunction with available seismic data sources, RT GNSS is sufficient and valuable for rapid earthquake characterization.
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Chen, Yuwei, Lingli Zhu, Jian Tang, Ling Pei, Antero Kukko, Yiwu Wang, Juha Hyyppä, and Hannu Hyyppä. "Feasibility Study of Using Mobile Laser Scanning Point Cloud Data for GNSS Line of Sight Analysis." Mobile Information Systems 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/5407605.
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The positioning accuracy with good GNSS observation can easily reach centimetre level, supported by advanced GNSS technologies. However, it is still a challenge to offer a robust GNSS based positioning solution in a GNSS degraded area. The concept of GNSS shadow matching has been proposed to enhance the GNSS based position accuracy in city canyons, where the nearby high buildings block parts of the GNSS radio frequency (RF) signals. However, the results rely on the accuracy of the utilized ready-made 3D city model. In this paper, we investigate a solution to generate a GNSS shadow mask with mobile laser scanning (MLS) cloud data. The solution includes removal of noise points, determining the object which only attenuated the RF signal and extraction of the highest obstruction point, and eventually angle calculation for the GNSS shadow mask generation. By analysing the data with the proposed methodology, it is concluded that the MLS point cloud data can be used to extract the GNSS shadow mask after several steps of processing to filter out the hanging objects and the plantings without generating the accurate 3D model, which depicts the boundary of GNSS signal coverage more precisely in city canyon environments compared to traditional 3D models.
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Fernandes, Rui, Carine Bruyninx, Paul Crocker, Jean-Luc Menut, Anne Socquet, Mathilde Vergnolle, Antonio Avallone, et al. "A new European service to share GNSS Data and Products." Annals of Geophysics 65, no. 3 (July 12, 2022): DM317. http://dx.doi.org/10.4401/ag-8776.
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This paper describes the new GNSS data and product services that have been developed within the context of the EPOS (European Plate Observing System) European Research Infrastructure Consortium (ERIC), which is part of the European Strategy Forum on Research Infrastructures. These services, optimized for Solid Earth research applications, endeavour to harmonise, and standardise Global Navigation Satellite System (GNSS) data collection and processing. They have been implemented by the members of the GNSS Data & Products (EPOS-GNSS), one of the Thematic Core Services (TCS) of EPOS with the active support of national and pan-European infrastructures (in particular the Regional Reference Frame Sub-Commission for Europe (EUREF) of the International Association of Geodesy). The optimized use of data from dozens of diverse European GNSS networks, installed not specifically for geodynamic studies, created additional requirements from an organizational and technical point of view, the solutions for which we describe in this article. The data flows from data suppliers and analysis centers to the various TCS Data & Product Portals are described, as well as their integration into the overall EPOS system. This is made through GLASS (GNSS Linkage Advanced Software System), a dedicated software package developed since 2016, whose architecture and functionalities are detailed here. Time series and other GNSS products computed at the several analysis centers are described as are the quality control steps that are performed. Finally, several user cases are presented that demonstrate how different stakeholders (from data providers to scientists) can benefit from the efforts being carried out by the EPOS- GNSS community.
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Lindskog, Magnus, Martin Ridal, Sigurdur Thorsteinsson, and Tong Ning. "Data assimilation of GNSS zenith total delays from a Nordic processing centre." Atmospheric Chemistry and Physics 17, no. 22 (November 24, 2017): 13983–98. http://dx.doi.org/10.5194/acp-17-13983-2017.
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Abstract. Atmospheric moisture-related information estimated from Global Navigation Satellite System (GNSS) ground-based receiver stations by the Nordic GNSS Analysis Centre (NGAA) have been used within a state-of-the-art kilometre-scale numerical weather prediction system. Different processing techniques have been implemented to derive the moisture-related GNSS information in the form of zenith total delays (ZTDs) and these are described and compared. In addition full-scale data assimilation and modelling experiments have been carried out to investigate the impact of utilizing moisture-related GNSS data from the NGAA processing centre on a numerical weather prediction (NWP) model initial state and on the ensuing forecast quality. The sensitivity of results to aspects of the data processing, station density, bias-correction and data assimilation have been investigated. Results show benefits to forecast quality when using GNSS ZTD as an additional observation type. The results also show a sensitivity to thinning distance applied for GNSS ZTD observations but not to modifications to the number of predictors used in the variational bias correction applied. In addition, it is demonstrated that the assimilation of GNSS ZTD can benefit from more general data assimilation enhancements and that there is an interaction of GNSS ZTD with other types of observations used in the data assimilation. Future plans include further investigation of optimal thinning distances and application of more advanced data assimilation techniques.
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Xiong, Zhaohui, Jizhang Sang, Xiaogong Sun, Bao Zhang, and Junyu Li. "Comparisons of Performance Using Data Assimilation and Data Fusion Approaches in Acquiring Precipitable Water Vapor: A Case Study of a Western United States of America Area." Water 12, no. 10 (October 21, 2020): 2943. http://dx.doi.org/10.3390/w12102943.
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There are two main types of methods available to obtain precipitable water vapor (PWV) with high accuracy. One is to assimilate observations into a numerical weather prediction (NWP) model, for example, the Weather Research and Forecasting (WRF) model, to improve the accuracy of meteorological parameters, and then obtain the PWV with improved accuracy. The other is the direct fusion of multi-source PWV products. Regarding the two approaches, we conduct a comparison experiment on the West Coast of the United States of America with the data from May 2018, in which the WRF data assimilation (DA) system is used to assimilate the Global Navigation Satellite System (GNSS) PWV, while the method by Zhang et al. to fuse the GNSS PWV, ERA5 PWV and MODIS (moderate-resolution imaging spectroradiometer) PWV. As a result, four groups of PWV products are generated: the assimilated GNSS PWV, the unassimilated GNSS PWV, PWV from the fusion of the GNSS PWV and ECWMF (European Centre for Medium-Range Weather Forecasts) ERA5 (ECWMF Reanalysis 5) PWV, and PWV from the fusion of the GNSS PWV, ERA5 PWV and MODIS PWV. Experiments show that the data assimilation based on the WRF model (WRFDA) and adopted fusion method can generate PWV products with similar accuracy (1.47 mm vs. 1.52 mm). Assimilating the GNSS PWV into the WRF model slightly improves the accuracy of the inverted PWV by 0.18 mm. The fusion of the MODIS PWV, GNSS PWV and ERA5 PWV results in a higher accuracy than the fusion of GNSS PWV and ERA5 PWV by a margin of 0.35 mm. In addition, the inland canyon topography appears to have an influence on the inversion accuracy of both the methods.
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Mensing, Christian, Stephan Sand, and Armin Dammann. "Hybrid Data Fusion and Tracking for Positioning with GNSS and 3GPP-LTE." International Journal of Navigation and Observation 2010 (August 2, 2010): 1–12. http://dx.doi.org/10.1155/2010/812945.
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Global navigation satellite systems (GNSSs) can provide reliable positioning information under optimum conditions, where at least four satellites can be accessed with sufficient quality. In critical situations, for example, urban canyons or indoor, due to blocking of satellites by buildings and severe multipath effects, the GNSS performance can be decreased substantially. To overcome this limitation, we propose to exploit additionally information from communications systems for positioning purposes, for example, by using time difference of arrival (TDOA) information. To optimize the performance, hybrid data fusion and tracking algorithms can combine both types of sources and further exploit the mobility of the user. Simulation results for different filter types show the ability of this approach to compensate the lack of satellites by additional TDOA measurements from a future 3GPP-LTE communications system. This paper analyzes the performance in a fairly realistic manner by taking into account ray-tracing simulations to generate a coherent environment for GNSS and 3GPP-LTE.
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Savchyn, І., Yu Otruba, and K. Tretyak. "The first Ukrainian permanent GNSS station in Antarctica: processing and analysis of observation data." Ukrainian Antarctic Journal, no. 2 (2021): 3–11. http://dx.doi.org/10.33275/1727-7485.2.2021.674.
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The main purpose of this work is to study and analyze the coordinate time series of the first Ukrainian permanent Global Navigation Satellite System (GNSS) station in Antarctica — Antarctic Station Academic Vernadsky (ASAV). We also aimed to do a comprehensive study of geophysical factors on the coordinate time series values and determine the values of the displacement components of this GNSS station. Processing of measurements was performed using the software Bernese GNSS Software v.5.2. The Bernese Processing Engine (BPE) module and the RNX2SNX (RINEX-TO-SINEX) processing algorithm were used to obtain daily solutions of permanent GNSS station ASAV. Daily solutions of the permanent GNSS station ASAV and the vector of its displacements were determined in the coordinate system IGb08. The vector of the permanent GNSS station ASAV has a northeasterly direction. The obtained results are consistent with the model of tectonic plate movements of this region. To study the characteristic periods of harmonic oscillations of coordinate time series of permanent GNSS station ASAV due to various geophysical factors. A set of studies was conducted, which included the development of an algorithm and a package of applications for processing time series and determining optimal curves that most accurately describe them. Thus, for each time series, the original equation is used to determine the optimal period of oscillation. As a result, an anomalous distribution of fluctuations in the values of permanent GNSS station ASAV with different periods was revealed — this indicates the complex nature of the influence of geophysical factors on the spatial location and confirms the need for systematic studies of such factors on the stability and displacement of GNSS station. It is established that the permanent GNSS station ASAV is exposed to seasonal oscillations, associated with changes in environmental conditions.
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Bai, W. H., Y. Q. Sun, Q. F. Du, G. L. Yang, Z. D. Yang, P. Zhang, Y. M. Bi, X. Y. Wang, C. Cheng, and Y. Han. "An introduction to the FY3 GNOS instrument and mountain-top tests." Atmospheric Measurement Techniques 7, no. 6 (June 24, 2014): 1817–23. http://dx.doi.org/10.5194/amt-7-1817-2014.
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Abstract. The FY3 (Feng-Yun-3) GNOS (GNSS Occultation Sounder) mission is a GNSS (Global Navigation Satellite System) radio occultation mission of China for remote sensing of Earth's neutral atmosphere and the ionosphere. GNOS will use both the global positioning system (GPS) and the Beidou navigation satellite systems on the China Feng-Yun-3 (FY3) series satellites. The first FY3-C was launched at 03:07 UTC on 23 September 2013. GNOS was developed by the Center for Space Science and Applied Research, Chinese Academy of Sciences (CSSAR). It will provide vertical profiles of atmospheric temperature, pressure, and humidity, as well as ionospheric electron density profiles on a global basis. These data will be used for numerical weather prediction, climate research, and ionospheric research and space weather. This paper describes the FY3 GNOS mission and the GNOS instrument characteristics. It presents simulation results of the number and distribution of GNOS occultation events with the regional Beidou constellation and the full GPS constellation, under the limitation of the GNOS instrument occultation channel number. This paper presents the instrument performance as derived from analysis of measurement data in laboratory and mountain-based occultation validation experiments at Mt. Wuling in Hebei Province. The mountain-based GNSS occultation validation tests show that GNOS can acquire or track low-elevation radio signal for rising or setting occultation events. The refractivity profiles of GNOS obtained during the mountain-based experiment were compared with those from radiosondes. The results show that the refractivity profiles obtained by GNOS are consistent with those from the radiosonde. The rms of the differences between the GNOS and radiosonde refractivities is less than 3%.
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Bai, W., Y. Sun, Q. Du, G. Yang, Z. Yang, P. Zhang, Y. Bi, X. Wang, C. Cheng, and Y. Han. "An introduction to FY3 GNOS instrument and its performace tested on ground." Atmospheric Measurement Techniques Discussions 7, no. 1 (January 27, 2014): 703–26. http://dx.doi.org/10.5194/amtd-7-703-2014.
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Abstract. The FY3 GNOS (GNSS Occultation Sounder) mission is a GNSS (Global Navigation Satellite System) radio occultation mission of China for remote sensing of Earth's neutral atmosphere and the ionosphere. GNOS will use both the Global Positioning System (GPS) and the Beidou navigation satellite systems on the China Feng-Yun-3 (FY3) series satellites. The first FY3-C was launched at 03:03 UTC, 23 September 2013. GNOS was developed by Center for Space Science and Applied Research, Chinese Academy of Sciences (CSSAR). It will provide vertical profiles of atmospheric temperature, pressure, and humidity, as well as ionospheric electron density profiles on a global basis. These data will be used for numerical weather prediction, climate research, and ionospheric research and space weather. This paper describes the FY3 GNOS mission and the GNOS instrument characteristics. It presents simulation results of the number and distribution of GNOS occultation events with the Regional Beidou constellation and the full GPS constellation, under the limitation of the GNOS instrument occultation channel number. This paper presents the instrument performance as derived from analysis of measurement data in laboratory and mountain-based occultation validation experiments at Mt. Wuling in Hebei Province. The mountain-based GNSS occultation validation tests show that GNOS can acquire or track lower elevation radio signal for rising or setting occultation events. The refractivity profiles of GNOS obtained during the mountain-based experiment were compared with those from radiosondes. The results show that the refractivity profiles obtained by GNOS are consistent with those from the radiosonde. The RMS of the differences between the GNOS and radiosonde refractivities is less than 3%.
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Ooi, Wei Han, Tajul Ariffin Musa, and Wan Anom Wan Aris. "REVIEW OF INTERNATIONAL GNSS DATA SHARING POLICY FRAMEWORKS AND PRACTICES." Journal of Information System and Technology Management 6, no. 24 (December 1, 2021): 254–64. http://dx.doi.org/10.35631/jistm.624024.
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Global Navigation Satellite Systems, or GNSS, is a space technology that has become an important component of positioning, navigation, and timing (PNT) in a broad variety of military and civilian applications. Accordingly, the GNSS is being supported with Continuously Operating Reference Station (CORS) networks which are a common type of GNSS ground-based augmentation infrastructure that governments and industry use to distribute centimetre accurate PNT information throughout the nation or region. In Malaysia, there are few CORS networks currently in services. It was difficult to integrate CORS networks even within the country since the CORS operating came from several different organizations. Furthermore, the CORS data sharing between the public and private sectors in providing precise positioning applications also challenging issue due to the fact that the data contains sensitive information. The relevant policy document on data sharing in the country is still vague. This paper review on existing GNSS data sharing policy framework and practice at the international and national levels. A number of countries from each continents were chosen to be studied further in order to identify the requirements that could be considered for adoption. The goal of this study is to create a clear conceptual framework for GNSS data sharing in the country, as well as to resolve some grey areas between public and private GNSS users.
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Duong, Thanh Trung, Kai-Wei Chiang, and Dinh Thuan Le. "On-line Smoothing and Error Modelling for Integration of GNSS and Visual Odometry." Sensors 19, no. 23 (November 29, 2019): 5259. http://dx.doi.org/10.3390/s19235259.
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Global navigation satellite systems (GNSSs) are commonly used for navigation and mapping applications. However, in GNSS-hostile environments, where the GNSS signal is noisy or blocked, the navigation information provided by a GNSS is inaccurate or unavailable. To overcome these issues, this study proposed a real-time visual odometry (VO)/GNSS integrated navigation system. An on-line smoothing method based on the extended Kalman filter (EKF) and the Rauch-Tung-Striebel (RTS) smoother was proposed. VO error modelling was also proposed to estimate the VO error and compensate the incoming measurements. Field tests were performed in various GNSS-hostile environments, including under a tree canopy and an urban area. An analysis of the test results indicates that with the EKF used for data fusion, the root-mean-square error (RMSE) of the three-dimensional position is about 80 times lower than that of the VO-only solution. The on-line smoothing and error modelling made the results more accurate, allowing seamless on-line navigation information. The efficiency of the proposed methods in terms of cost and accuracy compared to the conventional inertial navigation system (INS)/GNSS integrated system was demonstrated.
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TRETYAK, K., Т. KORLIATOVYCH, I. BRUSAK, and О. SMIRNOVA. "Differentiation of kinematics of the Dnister HPP-1 dam (based on the data of GNSS monitoring of spatial displacements)." Modern achievements of geodesic science and industry 42, no. II (September 1, 2021): 57–66. http://dx.doi.org/10.33841/1819-1339-2-42-57-66.
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The purpose of study is to generalize the vertical displacements of the GNSS network of spatial monitoring of the Dnister HPP-1 dam for the differentiation of its kinematics as well as to evaluate the impact of short-term geodynamic processes in the region. Object of study. The object of the study is the monitoring of the Dniester HPP-1 dam according to the GNSS network data of the stationary system for monitoring the spatial displacement of structures (SSMSDS) of the Dniester HPP-1. The basis of the Dnister SSMSDS are two base GNSS stations additionally equipped with a robotic total station, which are installed on a strong foundation and located at a distance of several hundred meters from the dam. There are control points equipped with a GNSS receiver, antenna and an angle reflector with a 3600 viewing angle on the crest of the dam. The results of GNSS measurements are transmitted to the Leica GNSS Spider software, which processes and determines the coordinates of the base and control points. The GEOMOS software performs a joint estimation of GNSS results and linear-angular measurements. Methodology. To generalize the displacements of GNSS stations of Dnister HPP-1 the method of statistical analysis of time series is used. Authors examine the covariance interrelationships between all GNSS stations of the stationary system for monitoring the spatial displacement of structures (SSMSDS) of the Dnister HPP-1, which are placed on the dam based on the results of measurements from 1.07.2017 to 31.03.2021. For the selected periods of anomalous short-term displacements, the average values of covariance for each GNSS station are calculated. Results. During the period from 1.07.2017 to 31.03.2021 and according to the results of covariance interrelation for most GNSS stations, 3 epochs of anomalous altitude displacements are established (T = 2017.8 ± 0.1, T = 2019.0 ± 0.1, T = 2019.4 ± 0.1). Based on the covariance analysis, it was found that for periods of anomalous vertical displacements, the kinematics of the GNSS station MP01 differs significantly from the kinematics of GNSS stations MP02-MP05. The kinematics of GNSS-stations MP02-MP05 is constant, which indicates the anomalous movement of the unit on which the GNSS-station MP01 is installed in relation to the other blocks of the dam of the Dnister HPP-1. Scientific novelty and practical significance. Authors proposed the method for studying the geodynamics possesses of large industrial areas covered by a network of GNSS stations. Based on the GNSS measurements the periods of anomalous displacement are reveled and further search for spatial kinematic interrelationships between pair of GNSS stations is established. The developed methodology can be used to differentiate the kinematics of structural elements with installed GNSS stations such as engineering structures, industrial areas, geodynamic polygons.
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Retscher, Günther, Daniel Kiss, and Jelena Gabela. "Fusion of GNSS Pseudoranges with UWB Ranges Based on Clustering and Weighted Least Squares." Sensors 23, no. 6 (March 21, 2023): 3303. http://dx.doi.org/10.3390/s23063303.
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Global navigation satellite systems (GNSSs) and ultra-wideband (UWB) ranging are two central research topics in the field of positioning and navigation. In this study, a GNSS/UWB fusion method is investigated in GNSS-challenged environments or for the transition between outdoor and indoor environments. UWB augments the GNSS positioning solution in these environments. GNSS stop-and-go measurements were carried out simultaneously to UWB range observations within the network of grid points used for testing. The influence of UWB range measurements on the GNSS solution is examined with three weighted least squares (WLS) approaches. The first WLS variant relies solely on the UWB range measurements. The second approach includes a measurement model that utilizes GNSS only. The third model fuses both approaches into a single multi-sensor model. As part of the raw data evaluation, static GNSS observations processed with precise ephemerides were used to define the ground truth. In order to extract the grid test points from the collected raw data in the measured network, clustering methods were applied. A self-developed clustering approach extending density-based spatial clustering of applications with noise (DBSCAN) was employed for this purpose. The results of the GNSS/UWB fusion approach show an improvement in positioning performance compared to the UWB-only approach, in the range of a few centimeters to the decimeter level when grid points were placed within the area enclosed by the UWB anchor points. However, grid points outside this area indicated a decrease in accuracy in the range of about 90 cm. The precision generally remained within 5 cm for points located within the anchor points.
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Perdiguer-López, Raquel, José Luis Berné-Valero, and Natalia Garrido-Villén. "Application of GNSS Methodologies to Obtain Precipitable Water Vapor (PWV) and Its Comparison with Radiosonde Data." Proceedings 19, no. 1 (July 25, 2019): 24. http://dx.doi.org/10.3390/proceedings2019019024.
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A processing methodology with GNSS observations to obtain Zenith Tropospheric Delay using Bernese GNSS Software version 5.2 is revised in order to obtain Precipitable Water Vapor (PWV). The most traditional PWV observation method is the radiosonde and it is often used as a standard to validate those derived from GNSS. For this reason, a location in the north of Spain, in A Coruña, which has a GNSS station with available data and also a radiosonde station, was chosen. Two GPS weeks, in different weather conditions were calculated. The result of the comparison between the GNSS- retrieved PWV and Radiosonde-PWV is explained in the last section of this paper.
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Wei, Y., and Y. Li. "IMPACT OF SENSOR DATA SAMPLING RATE IN GNSS/INS INTEGRATED NAVIGATION WITH VARIOUS SENSOR GRADES." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-3/W1-2022 (April 22, 2022): 205–11. http://dx.doi.org/10.5194/isprs-archives-xlvi-3-w1-2022-205-2022.
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Abstract. The fast-growing small-size equipment requires robust navigation with low power consumption and high positioning accuracy. However, as the mainstream robust navigation method against different environments, GNSS/INS causes excessive power dissipation. Considering downsampling is confirmed as a simple but efficient way to reduce energy usage, this paper focuses on the impact of sensor data sampling rate in GNSS/INS integrated navigation to give guidance for selecting proper GNSS/INS rates. Specifically, we first simulated data sequences with various sensor grades and then downsampled them into multiple sampling rates, followed by positioning accuracy evaluation. Experiment results have shown that GNSS interval caused more significant degradation of the navigation accuracy than the IMU rate. Meanwhile, the 5 sec GNSS interval with the 20 Hz IMU rate may be the most suitable for a power-accuracy trade-off solution in our experiments, which has a 16% reduction in positioning accuracy compared to the standard sampling rate combination (i.e, 1 sec GNSS interval and 200 Hz IMU sampling rate).
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Dimitrov, Nikolay. "Deformation analysis in central west Bulgaria using triangulation and GPS data." Reports on Geodesy and Geoinformatics 108, no. 1 (December 8, 2019): 23–26. http://dx.doi.org/10.2478/rgg-2019-0009.
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AbstractThe article discusses a method applied for combining the results of Global Navigation Satellite Systems (GNSS) and 75-year old triangulation measurements to estimate the crustal movements in central western Bulgaria region. It was examined for joint analysis based on the results of GNSS with angular measurements of the first order triangulation network in Bulgaria during the period 1923–1930 year. As a result of the processing of GNSS and angular measurements, horizontal velocities of 15 points, strain rates, and rotation rates have been obtained. The results show dominating N–S extension at a rate of 1–2 mm/y and the deformation is not uniformly distributed over the studied area. The obtained results indicate the possibility of using old angular measurement of first-order triangulation points, together with GNSS data, to obtain estimates of the horizontal crustal movements.
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Ziebold, Ralf, Daniel Medina, Michailas Romanovas, Christoph Lass, and Stefan Gewies. "Performance Characterization of GNSS/IMU/DVL Integration under Real Maritime Jamming Conditions." Sensors 18, no. 9 (September 5, 2018): 2954. http://dx.doi.org/10.3390/s18092954.
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Currently Global Navigation Satellite Systems (GNSSs) are the primary source for the determination of absolute position, navigation, and time (PNT) for merchant vessel navigation. Nevertheless, the performance of GNSSs can strongly degrade due to space weather events, jamming, and spoofing. Especially the increasing availability and adoption of low cost jammers lead to the question of how a continuous provision of PNT data can be realized in the vicinity of these devices. In general, three possible solutions for that challenge can be seen: (i) a jamming-resistant GNSS receiver; (ii) the usage of a terrestrial backup system; or (iii) the integration of GNSS with other onboard navigation sensors such as a speed log, a gyrocompass, and inertial sensors (inertial measurement unit—IMU). The present paper focuses on the third option by augmenting a classical IMU/GNSS sensor fusion scheme with a Doppler velocity log. Although the benefits of integrated IMU/GNSS navigation system have been already demonstrated for marine applications, a performance evaluation of such a multi-sensor system under real jamming conditions on a vessel seems to be still missing. The paper evaluates both loosely and tightly coupled fusion strategies implemented using an unscented Kalman filter (UKF). The performance of the proposed scheme is evaluated using the civilian maritime jamming testbed in the Baltic Sea.
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Baasansuren, Narangii, Uuganbaatar Dulamragchaa, Bukhtsooj Odsuren, and Battulga Ulziisaikhan. "Global Navigation Satellite Data Processing Equipment." Journal of Institute of Mathematics and Digital Technology 4, no. 1 (December 26, 2022): 78–84. http://dx.doi.org/10.5564/jimdt.v4i1.2664.
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In this work, a circuit-technical model of a data processing device for a global navigation satellite system (GNSS) was created. This prototype device was designed in accordance with the requirements of being able to determine the user’s location within a circle error of 2.5-5m, low price, and good availability of parts. The Kalman filter was also used to reduce the effect of noise. The positioning device is powered by direct current and can be connected to the car’s mains or battery.
Глобал Навигацийн Хиймэл Дагуулын Мэдээлэл Боловсруулах Төхөөрөмж
Хураангуй: Бид энэ ажлаараа глобал навигацийн хиймэл дагуулын (GNSS) мэдээлэл боловсруулах системийн схем-техникийн шийдэл загварыг гаргасан. Энэхүү загвар төхөөрөмжийг хэрэглэгчийн байршлыг 2,5-5м тойргийн алдааны хүрээнд тогтоох боломжтой, үнийн хувьд хямд, эд ангийн хувьд олдоц сайтай байх шаардлагын дагуу бүтээв. Мөн шуугианы нөлөөг бууруулахын тулд Калманы шүүлтүүрийг ашигласан. Байрлал тогтоох төхөөрөмж нь тогтмол гүйдлийн хүчдэлээр тэжээгдэх ба автомашины тэжээлийн хэлхээ болон батарейнд холбогдон ажиллах боломжтой.
Түлхүүр үгс: Байршил, GNSS, Arduino, траектор, микроконтроллер
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Samoylov, Alexey, Andrey Kostyuk, Viktor Potapov, and Yuriy Borodyansky. "The methods for processing and storage of data in global navigation satellite systems for the task of perimeter protection." E3S Web of Conferences 224 (2020): 02032. http://dx.doi.org/10.1051/e3sconf/202022402032.
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The methods for processing and storage of GNSS data for the task of perimeter protection are described. The article proposes a basic algorithm for the operation of a GNSS data collection, processing and storage system that allows you to track processed GNSS data on a remote web service in public formats, as well as send signals through a client mobile application to available platforms and systems about temporarily suspending or canceling GNSS data recording.
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Mirmohammadian, Farinaz, Jamal Asgari, Sandra Verhagen, and Alireza Amiri-Simkooei. "Improvement of Multi-GNSS Precision and Success Rate Using Realistic Stochastic Model of Observations." Remote Sensing 14, no. 1 (December 23, 2021): 60. http://dx.doi.org/10.3390/rs14010060.
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With the advancement of multi-constellation and multi-frequency global navigation satellite systems (GNSSs), more observations are available for high precision positioning applications. Although there is a lot of progress in the GNSS world, achieving realistic precision of the solution (neither too optimistic nor too pessimistic) is still an open problem. Weighting among different GNSS systems requires a realistic stochastic model for all observations to achieve the best linear unbiased estimation (BLUE) of unknown parameters in multi-GNSS data processing mode. In addition, the correct integer ambiguity resolution (IAR) becomes crucial in shortening the Time-To-Fix (TTF) in RTK, especially in challenging environmental conditions. In general, it is required to estimate various variances for observation types, consider the correlation between different observables, and compensate for the satellite elevation dependence of the observable precision. Quality control of GNSS signals, such as GPS, GLONASS, Galileo, and BeiDou can be performed by processing a zero or short baseline double difference pseudorange and carrier phase observations using the least-squares variance component estimation (LS-VCE). The efficacy of this method is investigated using real multi-GNSS data sets collected by the Trimble NETR9, SEPT POLARX5, and LEICA GR30 receivers. The results show that the standard deviation of observations depends on the system and the observable type in which a particular receiver could have the best performance. We also note that the estimated variances and correlations among different observations are also dependent on the receiver type. It is because the approaches utilized for the recovery techniques differ from one type of receiver to another kind. The reliability of IAR will improve if a realistic stochastic model is applied in single or multi-GNSS data processing. According to the results, for the data sets considered, a realistic stochastic model can increase the computed empirical success rate to 100% in multi-GNSS as well as a single system. As mentioned previously, the realistic precision of the solution can be achieved with a realistic stochastic model. However, using the estimated stochastic model, in fact, leads to better precision and accuracy for the estimated baseline components, up to 39% in multi-GNSS.
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Ortega, Lorenzo, Charly Poulliat, Marie Laure Boucheret, Marion Aubault Roudier, Hanaa Al-Bitar, and Pau Closas. "Low Complexity Robust Data Demodulation for GNSS." Sensors 21, no. 4 (February 13, 2021): 1341. http://dx.doi.org/10.3390/s21041341.
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In this article, we provide closed-form approximations of log-likelihood ratio (LLR) values for direct sequence spread spectrum (DS-SS) systems over three particular scenarios, which are commonly found in the Global Navigation Satellite System (GNSS) environment. Those scenarios are the open sky with smooth variation of the signal-to-noise ratio (SNR), the additive Gaussian interference, and pulsed jamming. In most of the current communications systems, block-wise estimators are considered. However, for some applications such as GNSSs, symbol-wise estimators are available due to the low data rate. Usually, the noise variance is considered either perfectly known or available through symbol-wise estimators, leading to possible mismatched demodulation, which could induce errors in the decoding process. In this contribution, we first derive two closed-form expressions for LLRs in additive white Gaussian and Laplacian noise channels, under noise uncertainty, based on conjugate priors. Then, assuming those cases where the statistical knowledge about the estimation error is characterized by a noise variance following an inverse log-normal distribution, we derive the corresponding closed-form LLR approximations. The relevance of the proposed expressions is investigated in the context of the GPS L1C signal where the clock and ephemeris data (CED) are encoded with low-density parity-check (LDPC) codes. Then, the CED is iteratively decoded based on the belief propagation (BP) algorithm. Simulation results show significant frame error rate (FER) improvement compared to classical approaches not accounting for such uncertainty.
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Orlando García H et al.,, Orlando García H. et al ,. "GNSS Data Processing through the Wavelet Transform." International Journal of Mechanical and Production Engineering Research and Development 10, no. 5 (2020): 555–64. http://dx.doi.org/10.24247/ijmperdoct202055.
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Khutorova, O. G., V. E. Khutorov, and G. E. Korchagin. "Parameters of Wave Processes from GNSS Data." Atmospheric and Oceanic Optics 35, no. 1 (February 2022): 52–56. http://dx.doi.org/10.1134/s1024856022010092.
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Khutorova, O. G., V. E. Khutorov, and G. E. Korchagin. "Parameters of wave processes from GNSS data." Optika atmosfery i okeana 34, no. 6 (2021): 458–62. http://dx.doi.org/10.15372/aoo20210612.
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Lines, Terence, and Anahid Basiri. "3D map creation using crowdsourced GNSS data." Computers, Environment and Urban Systems 89 (September 2021): 101671. http://dx.doi.org/10.1016/j.compenvurbsys.2021.101671.
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Marchan-Hernandez, J. F., E. Valencia, N. Rodriguez-Alvarez, I. Ramos-Perez, X. Bosch-Lluis, A. Camps, Francisco Eugenio, and Javier Marcello. "Sea-State Determination Using GNSS-R Data." IEEE Geoscience and Remote Sensing Letters 7, no. 4 (October 2010): 621–25. http://dx.doi.org/10.1109/lgrs.2010.2043213.
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Hochegger, G., and R. Leitinger. "Model assisted inversion of GNSS occultation data." Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science 26, no. 5 (January 2001): 325–30. http://dx.doi.org/10.1016/s1464-1917(01)00007-1.
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Timofeev, E. A., and G. S. Tsekhanovich. "INS simulator for debugging INS/GNSS data." IEEE Aerospace and Electronic Systems Magazine 24, no. 1 (January 2009): 38–40. http://dx.doi.org/10.1109/maes.2009.4772753.
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D’Angelo, G., L. Spogli, C. Cesaroni, V. Sgrigna, L. Alfonsi, and M. H. O. Aquino. "GNSS data filtering optimization for ionospheric observation." Advances in Space Research 56, no. 11 (December 2015): 2552–62. http://dx.doi.org/10.1016/j.asr.2015.10.002.
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Septiawan, Reza, I. Made Astawa, Arief Rufiyanto, and Tahar Agastani. "Metode Deteksi ‘Potential Security Threats’ Pada ADS-B Data dengan Memonitor EM Emisi Radiasi pada Jaringan Ethernet." Ultima Computing : Jurnal Sistem Komputer 11, no. 1 (August 30, 2019): 39–44. http://dx.doi.org/10.31937/sk.v11i1.1181.
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Precision, Navigation, and Timing (PNT) system based on Global Navigation Satellite System (GNSS) becomes significant in the air traffic management, especially in the use of Automatic Dependent Surveillance Broadcast system (ADS-B) for air traffic monitoring. Therefore the integrity of GNSS is significant to provide a reliable data necessary for ADS-B. GNSS Interference due to intentional or unintentional surrounding signal source may decrease the integrity of GNSS signal and therefore may result in the in-accurate position data of ADS-B message. ADS-B message itself is also vulnerable from potential security threats in their network. This paper proposed a methodology to detect potential security threats of ADS-B network system for both GNSS signal and ADS-B data by measuring and monitoring the electromagnetic radiated emission from ethernet cable IPv4 Cat5.
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Wang, Wenbo, Ignacio Aguilar Sanchez, Gianluca Caparra, Andy McKeown, Tim Whitworth, and Elena Simona Lohan. "A Survey of Spoofer Detection Techniques via Radio Frequency Fingerprinting with Focus on the GNSS Pre-Correlation Sampled Data." Sensors 21, no. 9 (April 25, 2021): 3012. http://dx.doi.org/10.3390/s21093012.
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Radio frequency fingerprinting (RFF) methods are becoming more and more popular in the context of identifying genuine transmitters and distinguishing them from malicious or non-authorized transmitters, such as spoofers and jammers. RFF approaches have been studied to a moderate-to-great extent in the context of non-GNSS transmitters, such as WiFi, IoT, or cellular transmitters, but they have not yet been addressed much in the context of GNSS transmitters. In addition, the few RFF-related works in GNSS context are based on post-correlation or navigation data and no author has yet addressed the RFF problem in GNSS with pre-correlation data. Moreover, RFF methods in any of the three domains (pre-correlation, post-correlation, or navigation) are still hard to be found in the context of GNSS. The goal of this paper was two-fold: first, to provide a comprehensive survey of the RFF methods applicable in the GNSS context; and secondly, to propose a novel RFF methodology for spoofing detection, with a focus on GNSS pre-correlation data, but also applicable in a wider context. In order to support our proposed methodology, we qualitatively investigated the capability of different methods to be used in the context of pre-correlation sampled GNSS data, and we present a simulation-based example, under ideal noise conditions, of how the feature down selection can be done. We are also pointing out which of the transmitter features are likely to play the biggest roles in the RFF in GNSS, and which features are likely to fail in helping RFF-based spoofing detection.
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Padma, Tatiparti, Swapna Raghunath, and Usha Kumari Chintalapati. "Equatorial Plasma Bubbles Identification with Single Frequency GNSS Receiver Data." F1000Research 12 (January 11, 2023): 44. http://dx.doi.org/10.12688/f1000research.127244.1.
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Ionosphere is the highest contributor of positional error in Global Navigation Satellite System (GNSS) owing to the trans-ionospheric signal delay, distortion and possible outage. Equatorial and Low latitudinal ionosphere experiences frequent perturbations in plasma density most of which is due to the presence of Equatorial Plasma Bubbles (EPBs). In order to improve positional and navigational precision of GNSS signals, EPBs must be identified and corrected. EPBs begin to manifest post-sunset and continue to thrive past midnight. This paper proposes a Rate of TEC Index (ROTI) based EPB identifier using single frequency GNSS receiver data. GNSS data has been collected from the archives of Scripps Orbit and Permanent Array Center (SOPAC). The raw data has been downloaded from the global continuous network station, IISC, located at Bangalore (13.0219°N, 77.5671°E) in Receiver Independent Exchange (RINEX) format. Analysis of EPB occurrence has been carried out for six consecutive years in the second half of the 24th solar cycle (2014-2019). The results show a clear surge in the number of EPBs identified in the course of equinoxes.
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Demyanov, Vladislav, Maria Sergeeva, Mark Fedorov, Tatiana Ishina, Victor Jose Gatica-Acevedo, and Enrique Cabral-Cano. "Comparison of TEC Calculations Based on Trimble, Javad, Leica, and Septentrio GNSS Receiver Data." Remote Sensing 12, no. 19 (October 8, 2020): 3268. http://dx.doi.org/10.3390/rs12193268.
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A Global Navigation Satellite System (GNSS) receiver is, to some extent, a “black box” when its data is used for ionospheric studies. Our results based on Javad, Septentrio, Trimble, and Leica GNSS receivers have proven that the accuracy of the slant Total Electron Content (TEC) calculation can differ significantly depending on the GNSS receiver type/model, because TEC measurements depend on the carrier phase tracking technique applied in a receiver. The correlation coefficient between carrier phase noise in L1 and L2 channels is considered as a possible indicator that shows if the L1-aided tracking technique or independent tracking is applied inside a receiver. An empirical model of the TEC noise component was provided to determine the TEC noise value in different types/models of GNSS receivers.