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Aquesta tesi es desenvolupa en el context de la missió Lunar GNSS Receiver Experiment de la NASA i la ASI, que té com a objectiu demostrar el posicionament, la navegació i el temps basats en GNSS a la Lluna mitjançant el desplegament d'un receptor multiconstel·lació del sistema de navegació per satèl·lit amb cobertura global. El projecte es desplega sota la supervisió del grup NavSAS del Politecnico di Torino. La finalitat del projecte és el desenvolupament d'una aplicació que permeti l'anàlisi i simulació de mesures GNSS sense processar. El software ha de ser modular, flexible i fàcil d'utilitzar. Outgoing

This paper attempts to analyze the occurrence of ionospheric irregularities using RINEX data obtained from the UNAVCO GNSS station BDMT located in Bahir Dar, Ethiopia ( 11.5998 ° N, 37.3597 ° E) from January to December, 2015 based on the Rate of Change of Total Electron Content(ROTI) values. Large values of ROTI ⩾ 0.5 are observed in April followed by March and May, but in the remaining months of the year, the values of ROTI are small. April has shown the highest occurrence of ionospheric irregularities, but June shows the lowest occurrence of irregularities. Generally, for seasonal variation, the highest occurrence of ionospheric irregularities occurs during April, March and May and other months show relatively low ionospheric irregularities. We also observed that the occurrence of ionospheric irregularity varies from day to day and is more frequent during the post-sunset hours 18:00UT to 20:00UT(21:00LT to 23:00LT) for both quiet and disturbed days at low latitudes, Bahir Dar, Ethiopia. Finally, from the ROTI values, we have confirmed that ionospheric irregularities that are responsible for ionospheric scintillation are usually nighttime phenomena.

GNSS station movements as an indicator of the movement of the Earth’s crust are determined by many researchers with the use of various position and trend determination methods. One of such methods is PPP method which allows the determination of a trend for the station without a correlation (direct determination of the position of each station separately). To achieve accuracy comparable with relative positioning, there is the need to use external, high‑precision data or models (e.g. precise satellite orbits and clocks, ionosphere and troposphere models, etc.) while the PPP method is applied.The main purpose of the presented research is preliminary analyses of the results of processing daily GPS observations from permanent stations with the use of the PPP method. Daily GPS observational data in RINEX format have been acquired from a total of nine selected GNSS permanent stations from the Polish ASG EUPOS and the Ukrainian UA-EUPOS/ZAKPOS systems. As external data for PPP solutions JPL products have been used. A seven‑year time series was created for each station.

The tropospheric delay is an essential source of error for positioning using the Global Navigation Satellite System (GNSS). Scientific applications of GNSS positioning such as the study of earth crust deformation and earthquake prediction require high accuracy in positioning, an analysis of tropospheric delay calculations is needed to improve the accuracy of GNSS positioning. One part of the tropospheric delay is Zenith tropospheric delays (ZTD), which are estimated using the Precise Point Positioning (PPP) method. ZTD estimates can be beneficial for meteorological applications, for example, is the estimation of water vapor levels in the atmosphere from the estimated ZTD. We use GNSS data from the BAKO station in Cibinong and JOG2 station located in Yogyakarta. The GNSS data format is an Independent Exchange Receiver (RINEX), which we extracted using the sophisticated open-source GNSS software, called goGPS version 1.0 Beta from Geomatics Research and Development s.r.l. - Lomazzo, Italy. We validate the results of the extraction process with two international tropospheric products from International GNSS Services (IGS) with commercial software Bernese version 5 and the University of Nevada Reno (UNR) with software from NASA Jet Propulsion Laboratory (JPL) namely GIPSY / OASIS II. Epoch in this study, we use days of the year (DOY) 022-025 / 22-25 January representing the rainy season and DOY 230-233 to coincide on August 17-20 representing the dry season 2018. Our results obtained ZTD values both in January and August, and the two BAKO and JOG2 stations were consistent and worked well at different times and stations. RMS throughout DOY, both at BAKO and JOG2 stations, show small values

High-precision of Low Earth orbit (LEO) satellite orbit is essential for some applications having real-time requirements, such as LEO navigation enhancement, real time scientific satellite research, and so on. Currently, more mature means for real-time orbit determination of LEO satellites rely on spaceborne GPS data and RINEX/DORIS 3.0 data. However, most researchers conduct experiments using spaceborne GPS data or RINEX/DORIS 3.0 data separately, and the experiment results from combining the two types of data simultaneously have not been obtained. Therefore, we evaluate simulated real-time orbit determination capability of using the RINEX/DORIS 3.0 phase observations and spaceborne GPS pseudo-range observations from the HY2A satellite in this paper. Since the 1-km precision of the RINEX/DORIS 3.0 pseudo-range observations are unfavorable for the initial orbit, the GPS pseudo-range are used for this computation. But, the RINEX/DORIS 3.0 phase observations are used to solve the real-time orbit of HY2A satellite. Our analysis results are: (1) the three-dimensional (3D) position accuracy of HY2A satellite calculated by the spaceborne GPS pseudo-range is 6.803 m, which meets the initial orbit positional accuracy requirement. The initial orbit velocity requirement can be met when the 5–7th-order Lagrangian interpolation method is used to solve the satellite velocity. The 3D-RMS values of the HY2A satellite velocity is smaller than 0.500 m/s, indicating the initial velocity accuracy requirement is satisfied. (2) After Kalman filter convergence, the agreement of the comparison with the CNES precise orbit shows better than 0.100 m in radial position, an RMS of 0.373 m in 3D total position, and an RMS of 0.374 mm/s in 3D total velocity. The results suggest that the radial position accuracy is better than 0.100 m, and could meet some HY2A altimetry applications. In the course of this study, a Fortran-based prototype real-time orbit determination system RTODLEO (Real-Time Orbit Determination Software for Low Earth Orbit Satellite) was developed and used for the analysis. The results from thirteen-day of real-time orbit determination also validate the RTODLEO software, and show it is reliable.

The new GPS L5 signal, is a part of the U.S. efforts to modernize its global positioning system (GPS). It was designed to support safety of life applications such as civil aviation navigation. Its structure designed to provide higher performance in terms of measurement accuracy. Till now, the GPS system cannot transmit L5 from all satellites. So, in this paper a GPS simulator software in MATLAB environment was implemented to simulate RINEX observations files with the three frequencies. MATLAB: GPSDP (GPS Differential Processing) program was used to process static and kinematic data from all three frequencies . RINEX files for both base and rover stations had been generated for different baselines lengths 5, 50 and 100 km approximately in different day times. These data are used to study the impact of the third frequency on rate of resolving integer ambiguities and the time needed to fix the integer ambiguities correctly. Also, the positioning accuracy after adding the third frequency to dual frequencies data. All parameters are studied under variation of ionosphere intensities. The results of experiments have been illustrated and they show efficiency of using the third frequency over dual frequencies.

The ionospheric anomalies observed before any notable earthquake have become the subject of predictive research in the field of seismo-ionospheric coupling and/or Solid Earth-Atmosphere. In this paper, the concept of ionospheric modeling has been applied using total electronic content (TEC); derived from dual-frequency GPS recordings from about sixty permanent geodetic stations. The study and the analysis of the anomalous TEC variations, quantifiable on a regional scale, allowed us to detect the principal precursors of the Mw 5.5 earthquake that hit Oran on June 06th, 2008. The envisaged analytical approach is based principally on the time delays estimation relating to the seismic responses from the triggering (lithospheric seismic source) until their recording in data Rinex (GPS_IGS stations) through the reflection system of the electromagnetic waves on the ionospheric level (F2-layer). Indeed, in term of location, the longitude-latitude coordinates of the Oran event epicenter (0.658 ° W, 35.883 ° N) affecting the coastal margin of Western Algeria without too much material damage. Although the magnitude of this earthquake is qualified moderate (Mw 5.5, seismic intensity scale V-VI), one can observe apparent disturbances in the terrestrial electromagnetic spectrum associated with ionospheric TEC variations. In the domain of geodetic data analysis, we have noted a significant increase in the ionospheric TEC, which announces the arrival of a seismic precursor several days before the main studied event. Against this background, we emphasize that any seismic event, of significant magnitude, often carries information associated with other variants involved in the package of earthquake studied. Among these variants we evoke the effect of the magnetic field and the effect of the surrounding environment, etc. As for the specific behavior of the GPS_TEC signal, obtained from the Rinex data, and its interaction with the associated seismic activity, we highlight the existence of a spectral conformity between the geomagnetic field and that of the TEC content (spontaneous polarization of the TEC). Finally, we have just confirmed the effectiveness of this forecasting approach which relates the seismo-ionospheric precursors that are embedded in the physical trace of the electromagnetic signal relative to significant and / or moderate earthquakes (M ≥ 5); such as the envisaged case of the 2008 Oran event.

The navigation technology has developed rapidly and immensely over the past few decades. Among the multiple navigation technologies, the representative and promising techniques are Real-time Kinematic (RTK) technique and Simultaneous Localization and Mapping (SLAM). RTK can provide real-time positioning results with high accuracy, while SLAM can not only locate the user but also construct a map of the new ambient. The first smartphone, the Xiaomi MI 8, equipped with the dual-frequency Global Navigation Satellite System (GNSS), hit the market in May 2018, providing valid carrier-phase measurements for RTK owe to the developer option of ”Force full GNSS measurements.” Nevertheless, RTK underperforms in urban areas as the buildings and trees can block the satellite signals. RTK cannot even provide positioning results when the GNSS outage happens. However, SLAM can effectively make up the drawbacks of RTK as it utilizes no more information than the images. SLAM can also be combined with the Inertial Measurement Unit (IMU) called Visual-Inertial SLAM (VI-SLAM,) with the improvement of accuracy and robustness. Therefore, our study mainly aims to confirm the feasibility of continuous positioning based on RTK and VI-SLAM with the Xiaomi MI 8. An application is developed to execute the functions, including logging images, measurements of IMU, and GPS measurements in Receiver INdependent EXchange (RINEX) format with the Xiaomi MI 8. The performances of RTK with and without the assistance of VI-SLAM are assessed respectively in the urban area. The experimental results demonstrate that the combination of RTK and VI-SLAM based on smartphones can effectively provide continuous positioning results. We believe our application will facilitate research and development in relation to positioning algorithms. Readers have access to this application at https://github.com/Nronaldo/CIGRLogger.

[ES] El acceso y el uso del sistema global de navegación por satélite (GNSS) en dispositivos móviles como teléfonos inteligentes ha transformado el concepto de posicionamiento preciso. Este Trabajo Final de Grado analiza las posibilidades de trabajar observables GNSS en dispositivos móviles con sistema operativo Android. El rendimiento del Smartphone se ha comparado con un receptor geodésico con el fin de establecer la posición mediante el uso de datos, tanto con datos brutos raw, como con observables GNSS en formato Rinex, de múltiples constelaciones, pseudorango de doble frecuencia y fase portadora recopilados del teléfono inteligente. Para ello, se realizarán dos tipos de trabajos habituales en geomática: posicionamiento estático y cinemático en postproceso., [EN] The access and use of the Global Navigation Satellite System (GNSS) on mobile devices such as Smartphones with Android operating system has transformed the concept of precise positioning. This Final Degree Project analyses the possibilities of working GNSS observables on mobile devices with Android operating system. The performance of the Smartphone has been compared with a geodetic receiver in order to determine the position using both raw data and GNSS observables in RINEX format, multiple constellation, dualfrequency pseudorange and carrier phase data collected from the Smartphone. To this end, two types of work commonly used in geomatics will be carried out: static positioning and kinematic positioning in post-processing.

Nowadays, with the incursion of low-cost GNSS receivers with modern characteristics, it is common to investigate and apply new methodologies and solutions with different receivers of this nature. Based on this fact, the performance of the solution obtained from the low-cost GNSS receiver is evaluated compared to a geodetic grade GNSS receiver at different sampling frequencies for the PPP-static and PPP-kinematic modes. For this, the original RINEX observation files were analyzed and decimated into different sampling rates as 0.1, 0.2, 1, 5, 15 and 30 s with TEQC software. All RINEX files were submitted to the Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP) online service for processing with static and kinematic modes. The PPP-derived coordinates from the low-cost GNSS receiver were compared with the geodetic receiver to evaluate the obtained solution. The results reveal that the behavior of all studied sampling rates from the low-cost GNSS receiver are constant in achieved positioning. In addition, the achieved precision shows that it is recommendable to use a high sampling rate to obtain a cm level in PPP-static mode by using a low-cost GNSS receiver, this mode being the most accurate and potential alternative for structural health monitoring studies, mapping and positioning in urban areas.

Una gran variedad de sectores, como telecomunicaciones, finanzas y distribución de energía requieren de una sincronización precisa. Cuando se trata de sincronización de alta precisión entre puntos lejanos (>1000 km) se emplean habitualmente técnicas de transferencia de tiempo mediante satélites de geonavegación. Dentro de estas técnicas, la empleada mayoritariamente se conoce como Common View y consiste en el empleo de receptores especializados y relojes atómicos de elevado coste. En esta investigación se ha desarrollado un sistema embebido con capacidad para realizar common view empleando un oscilador de coste medio y una alta frecuencia de correcciones. Esto reduce en dos órdenes de magnitud el coste de la sincronización, aumentando así el número de posibles usuarios y abriendo un abanico de aplicaciones., Este trabajo ha sido financiado gracias al Programa de Garantía Juvenil y al proyecto Amiga-7.

Permafrost warming is coinciding with accelerated mass movements, talking place especially in steep, mountainous topography. While this observation is backed up by evidence and analysis of both remote sensing as well as repeat terrestrial surveys undertaken since decades much knowledge is to be gained about the specific details, the variability and the processes governing these mass movements in the mountain cryosphere. This dataset collates data of continuously acquired kinematic observations obtained through in-situ Global Navigation Satellite Systems (GNSS) instruments that have been designed and implemented in a large-scale multi field-site monitoring campaign across the whole Swiss Alps. The landforms covered include rock glaciers, high-alpine steep bedrock bedrock as well as landslide sites, most of which are situated in permafrost areas. The dataset was acquired at 54 different stations situated at locations from 2304 to 4003 m a.s.l and comprises 209’948 daily positions derived through double-differential GNSS post-processing. Apart from these, the dataset contains down-sampled and cleaned time series of weather station and inclinometer data as well as the full set of GNSS observables in RINEX format. Furthermore the dataset is accompanied by tools for processing and data management in order to facilitate reuse, open alternate usage opportunities and support the life-long living data process with updates. To date this dataset has seen numerous use cases in research as well as natural-hazard mitigation and adaptation due to climate change., Earth System Science Data Discussions, ISSN:1866-3591

The distribution of clock correction and ephemeris (CCE) parameters in navigation messages broadcast by operational satellite vehicles (SVs) of the Global Navigation Satellite System (GNSS) is studied. For this purpose, two evaluation metrics are proposed, namely atypical navigation message structures and time to complete CCE sets (TTCS). The evaluation metrics are used to analyze three and a half years of operational Galileo F/NAV and GPS LNAV messages. The study considers arbitrary and healthy-only signal-in-space (SIS) health statuses. The frequently used receiver independent exchange format (RINEX) navigation files are shown to not provide sufficient information to determine the CCE parameters transmitted at every time instance. Due to the identified limitations, binary navigation data collected by a worldwide network of monitoring stations are used for the analysis. During operations, the maximum of the TTCS metric is shown to be impacted by the issue of data (IOD) update periods and structures with mismatched IOD parameters, potentially introducing an additional delay to the time to first fix (TTFF). The message timing requirements of dual-frequency multi-constellation (DFMC) satellite-based augmentation system (SBAS) are shown to be in line with the minimum times needed to obtain multiple complete Galileo F/NAV and GPS LNAV CCE sets.

Until a few years ago, a precise survey was only possible using global positioning system (GPS) and Global'naja Navigacionnaja Sputnikovaja Sistema (GLONASS) constellations, but the result was not guaranteed under conditions of poor sky visibility, as in urban canyons. Currently, the number of Global Navigation Satellite System (GNSS) satellites in orbit has strongly increased thanks to the great evolution of the Galileo and the Beidou constellations. In this paper, we investigate the impact of using different constellations and their combinations, in static positioning with the classical differencing approach. For this purpose, two distinct baselines of different lengths (10 and 60 km) were processed using commercial software over a period of one year (2018.24-2019.24). Data were acquired by permanent stations belonging to the European Permanent Network (EPN) network providing 24-h observing sessions. Two datasets were tested, one consisting of 24-h Receiver Independent Exchange Format (RINEX) files and the other considering only 2-h sessions of data acquisition. In both cases, a one-year-long time span has been considered. The baselines were processed considering each of the four GNSS constellations and a series of combinations, for a total of eight solutions. Results have been evaluated looking at the accuracy and repeatability of the coordinates, together with the main constellation parameters. During the analyzed period the number of contemporary visible satellites of the BeiDou constellation was still too poor over the considered area, and therefore this constellation did not provide comparable precisions in respect to the others. Positioning precision provided by the Galileo constellation has shown to be very close to those given by GPS or GLONASS, with a significant difference only on the height component, especially in the case of processing 2-h data. As for 24-h observing sessions, the use of multiconstellation observables actually leads to small improvements in precision with respect to the use of GPS data only, mainly appreciable considering the vertical component. The GPS-Galileo combination gives quite the same performances of the GPS-GLONASS one, but it can potentially take advantage of the integrity message provided by the European constellation.

Errors induced by the ionosphere on global navigation satellite systems (GNSS) signal propagation significantly affect the positioning calculation done by ground receivers. These ionospheric errors may end up reaching tens of meters in the final positioning calculation. In this study, the ionospheric range error (IRE) was monitored over the local ionosphere of BAHR, Bahrain (26.209N, 50.608E) during the period of the 23rd solar cycle. IRE values were obtained through observation data derived from RINEX files and compared with NeQuick 2 (NQ2) model calculations. It was found that, for the region of study, NQ2 overestimated the total electron content (TEC) values as compared to observation data, resulting in higher IRE values of up to 12 m. However, IRE derived using GNSS observations and NQ2 follow similar trends over the course of the solar cycle. IRE values were also compared to the smoothed sunspot number (SSN) and F10.7 indexes which resulted in significant correlation between the seasonal calculation of IRE and solar activity. Throughout the 23rd solar cycle, the highest IRE values were found during the equinoxes and the lowest during solstices. The largest IRE value was observed in the vernal equinox of 2000 (19.13 m), while the lowest IRE value was observed in the winter solstice of 1998 (0.276 m).

GNSS receiver data crowdsourcing is of interest for multiple applications, e.g., weather monitoring. The bottleneck in this technology is the quality of the GNSS receivers. Therefore, we lay out in an introductory manner the steps to estimate the performance of an arbitrary GNSS receiver via the measurement errors related to its instrumentation. Specifically, we do not need to know the position of the receiver antenna, which allows also for the assessment of smartphone GNSS receivers having integrated antennas. Moreover, the method is independent of atmospheric errors so that no ionospheric or tropospheric correction services provided by base stations are needed. Error models for performance evaluation can be calculated from receiver RINEX (receiver independent exchange format)data using only ephemeris corrections. For the results, we present the quality of different receiver grades through parametrized error models that are likely to be helpful in stochastic modeling, e.g., for Kalman filters, and in assessing GNSS receiver qualities for crowdsourcing applications. Currently, the typical positioning precision for the latest smartphone receivers is around the decimeter level, while for a professional-grade receiver, it is within a few millimeters.

Introduction: This publication is the product of research developed within the research lines of the Advanced and Large-scale Computing (Cage) research group throughout 2018, which supports the work of a master’s degree in Systems Engineering at the Industrial University of Santander. Objetive: An approach to a cooperative positioning algorithm is described in this paper, where a set of devices exchange GPS satellite observables and distance estimations with nearby devices in order to increase their positioning accuracy. Methodology: Different scenarios are established where GPS receivers exchange satellite information, using different ionospheric correction models, with the purpose of evaluating which conditions potentially improve the position accuracy. Conclusions: The results show our approach yields increased accuracy when all receivers use the same ionospheric correction model. Moreover, it was observed that the noise levels and uncertainty usually due to factors related to distance from remote devices to the main receiver did not influence positioning improvement when the separation between receiver pairs was large. Originality: The proposed algorithm allows for exploitation of the nature of the problem without increasing complexity at the hardware and software level, and to offer a low-cost cooperative positioning solution alternative. Restrictions: The results presented in the document are based on the execution of the cooperative algorithm using Rinex files of gnss reference stations. So, for scenarios in which the separation distances between reference stations are very high, the error levels in cooperative positioning can be very large.

El procesamiento de observaciones GNSS en línea ha venido en aumento en los útlimos años. Diferentes servicios como el ofrecido por el Canadian Space Reference System (CSRS), bajo la modalidad de Posicionamiento Puntal Preciso (PPP), brinda la posibilidad de conocer de una manera rápida y efectiva la posición tridimensional a partir de un archivo rinex. Aprovechando estos resultados, se procesaron archivos diarios por un periodo de 2,5 años y para 10 estaciones GNSS de Costa Rica integradas al Sistema de Referencia Geocéntrico para las Américas (SIRGAS). Las coordenadas geocéntricas derivadas del procesamiento PPP en línea, se consideraron como vectores de observaciones para la estimación de sus velocidades (Moya et al, 2017). No obstante, previamente se programó e implementó una prueba estadística denominada test de errores groseros (Pelzer, 1985) para la estimación de potenciales observaciones atípicas. Esta prueba es usada frecuentemente en el análisis de redes geodésicas (Knight et al, 2010), sin embargo, ahora se aplicó en el modelo lineal de cálculo de velocidades. El proceso de ajuste para el cálculo de las velociadades se hizo de manera iterativa por estación y por coordenada, excluyendo las observaciones groseras marcadas por el test en cada proceso. En promedio esta prueba detectó una serie de observaciones con residuos que variaron entre los -50 mm y los 40 mm en sus tres componentes. Finalmente con las velocidades depuradas de errores groseros se validaron respecto a la solución multianual SIR15P01 de SIRGAS, tomando como a la época de referencia 2017,0. Las diferencias promedio entre ambas determinaciones fueron de _15 mm.

National geodetic reference systems can be continuously monitored using applications of Global Navigation Satellite Systems (GNSS). Within these reference systems, Continuously Operating GNSS Reference Stations (CORSs) are often employed to provide 24/7 satellite tracking data. Understanding the influence of the surroundings of a CORS on the recorded satellite tracking data is indispensable for quality analysis of both acquired data and station location suitability. One of the main sources of inaccurate tracking data is the result of the combined reception of direct as well as indirect, environment-reflected satellite signals by the CORS, in which the latter can be considered interference compromising the signal’s accuracy. The magnitude of this interference is usually evaluated by the Signal-to-Noise Ratio (SNR), a parameter stored by default in the RINEX interchange format for raw GNSS data. The technique of GNSS Interferometric Reflectometry (GNSS-IR) exploits the availability of the SNR data and has been frequently used for applications such as soil moisture monitoring, detection of vegetation water content, measuring snowfall or determining water levels. In this research, we propose to employ GNSS-IR to investigate the effect of the surrounding on a CORS in order to evaluate station location suitability. More specifically, this will be done by using the signal to estimate the Reflector Height (RH), which depends on the reflector roughness (i.e. the roughness of the surface surrounding the CORS). The quality of this estimation will be validated by comparing with the actual measurement of the RH of the CORS on site.In our approach, a statistically sound method is developed quantifying the stability of the RH determination. The proposed methodology consists of using Lomb-Scargle periodograms to select the dominant oscillation frequency of each satellite track SNR data, followed by an analysis and filtering of the peak amplitudes. This leads to the analysis product: number of significant peak amplitudes for an individual CORS over (sub-)daily timeframes. With historical data covering long time periods, statistical analysis of the (sub-)daily timeseries allows for reviewing the station location suitability. In Belgium, CORS are located on two typical positions: in Flanders, the 32 antennas are mainly installed on rooftops of buildings; in Wallonia, the 23 antennas are installed on a concrete pole next to highways. There is no evidence of one choice of station position being more suitable than the other. However, cars are known to be an important factor in signal reflections. In our analysis of station suitability, the effect of cars passing by on the highway near a Walloon CORS, but also movements on, e.g., parking lots next to buildings with a rooftop CORS, will be investigated. With the developed methodology, guidelines for station location selection could be further developed, together with a system to continuously monitor CORS position suitability using GNSS-IR, triggering a warning when significant changes in the environment changes the local reflectometry fingerprint.

Here we test the capability of the Broadcast Ephemeris Message, in both its GPS-like (Keplerian ellipse with secular and periodic perturbations) and Glonass-like (numerical integration of a 9D state vector) formats, to reproduce a corresponding precise ephemeris. We start from a daily Rinex 3.04 navigation file for multiple GNSS and the corresponding SP3 precise orbits computed by CNES (Centre National d’Etudes Spatiales) for GPS, Glonass, Galileo and CODE (Center for Orbit Determination in Europe) for Beidou, and compute broadcast ECEF coordinates and clocks. The pre-fit discrepancies are converted by least squares to corrections to the broadcast ephemeris parameters in two-hour consecutive arcs (for GPS, Galileo and Beidou) and to a set of seven Helmert parameters for the entire day, to align in origin, orientation and scale to the common GNSS IGS14 Reference Frame. The test cases suggest that the Broadcast Ephemeris Message, complemented with Reference Frame information, can reproduce the precise ephemeris and clocks with centimetric accuracy for intervals at least equal to the respective validity times, typically 2 h. The broadcast ephemeris of Glonass consists of three initial positions and velocities at epoch, three constant Lunisolar accelerations for the satellite position, and of three polynomial coefficients for the satellite clock. The 9D vector of state is numerically integrated to generate position and velocity data within the validity time (0.5 h) of the message. To test the capability of this model to reproduce the corresponding values of a precise ephemeris, the 9D vector of state and clock polynomials are adjusted until the rms (root mean squared spread) of the post-fit residuals relative to a precise orbit (CNES’s in our case) is minimum. We show in one example (one satellite for one day) that the Glonass type of message can reproduce a precise ephemeris and clock with a rms spread of 0.025 m over one-hour arcs. Volume computations on one month of data with all available satellites confirm the test results. For GPS, Glonass, Galileo and Beidou, the best fitting clock values predicted by our second order polynomials, based on a 15 min sampling, are shown to fit the corresponding high rate clocks (30 s sampling) of MGEX with zero bias and a rms spread of 0.062 ns (GPS G01), 0.023 ns (Galileo E01), 0.43 ns (Glonass R01), 0.086 ns (Beidou C07) and 0.086 ns (Beidou C12). Modifications to the GPS-like message structure and Glonass algorithm are proposed to increase the validity time by including the effect of the 3rd zonal harmonic of the Earth’s gravity field. The potential of the RTCM messages for broadcasting the improved navigation message is reviewed.

The network of permanent GNSS stations of the Republic of Srpska is located in a fairly seismic area and belongs to different sides of regional faults. This paper provides an overview of the stability tests for fifteen permanent stations of the SRPOS network using the published precise ephemeris of the International GNSS Service (IGS) and the downloaded RINEX data from the permanent GNSS stations of the SRPOS network. The research was conducted for the data taken during the period from April 2015 to March 2016. The paper presents position vectors for permanent stations ranging from 0.71 mm (permanent station Srbac) to 22 mm (permanent station Nevesinje). Key words: GNSS, permanent station, SRPOS network, reference system, IGS Reference Frame station, precise ephemerides

[EN] Nowadays, as the number of GNSS services are increasing, it is necessary to study and evaluate with real data the enhanced capabilities which these positioning products can provide, and how they are evolving compared with their legacy services and its competitors. Among the emerging positioning services, it is noteworthy Europe's GALILEO system, which is close to reach its full operational capability, and is willing to fulfill competitive user level performances which can be used through its open service signals: E1, E5a and E5b. On the legacy side, the most remarkable constellation is USA's GPS, which has been achieving a positioning standard service with the C/A signal and a precise positioning service for military purposes with the P signal. In addition, GPS evolutions will provide a civilian service through more robust signals, such as the L5. The objective of this work is to compare open positioning services from GPS and GALILEO constellations by analyzing their accuracy and integrity performances obtained from a pre-planned campaign, taking as reference-data the IGS station network. The positioning methodology to be used is post-processing single-frequency pseudorange observations in static mode. For committing this purpose, the main workload is focused on developing a configurable and flexible SW tool which is able to batch the pseudorange observations provided by the spatial frame of the GPS and GALILEO satellites, in order to estimate the receiver's position by means of a Least Squares routine. Lately, these data will be inputted in other analysis tools, which will also be developed in the framework of this project, in order to summarize and display the obtained performances. Consequently, and supported by the obtained results, the conclusions regarding the evolution of the studied services will be drawn., [ES] Actualmente, mientras el número de servicios GNSS disponibles aumenta, resulta necesario evaluar con datos reales las mejoras que ofrecen los nuevos productos de posicionamiento, y cuál es su desempeño y evolución respecto de sus servicios antecesores y el de sus competidores. Entre los servicios de posicionamiento emergentes, resulta de especial interés el proporcionado por la constelación Europea de GALILEO, la cual está cerca de alcanzar su completa capacidad operacional, y que resulta prometedora en cuanto a sus requisitos de prestaciones a nivel usuario, que pueden obtenerse mediante el uso de las señales de su servicio abierto: E1, E5a y E5b. De entre los sistemas ya existentes, el más destacado es el proporcionado por la constelación Estadounidense de GPS, el cual ha estado permitiendo con la señal C/A un servicio de posicionamiento estándar y un servicio de posicionamiento preciso con la seña P para fines militares. Adicionalmente las evoluciones del sistema GPS planean transmitir un servicio civil con señales más robustas, como puede ser la L5. El objetivo de este trabajo es comparar los servicios abiertos de posicionamiento de las constelaciones de GPS y GALILEO, mediante el análisis de sus prestaciones de precisión e integridad obtenidas de una campaña de observación, dónde los datos de referencia a usar son la red de estaciones del IGS. La metodología de posicionamiento a implementar es el post-procesado de observables de pseudo-rango mono-frecuencia en modo estático. Para alcanzar este objetivo, el esfuerzo principal estará enfocado en el desarrollo de una herramienta SW totalmente configurable por el usuario, que sea capaz de procesar los observables de pseudorango proporcionados por el marco de referencia espacial que forman los satélites de GPS y GALILEO, para posteriormente obtener las posiciones del receptor por medio de un algoritmo de estimación por mínimos cuadrados. Los resultados que se obtengan de este procesamiento serán transmitidos a otras herramientas de análisis, las cuales se desarrollarán también en el marco de este proyecto, con la finalidad de resumir y presentar de manera gráfica las prestaciones obtenidas de la campaña. Finalmente, con el soporte de estos resultados, se expondrán las conclusiones sobre el desempeño y la evolución de los servicios anteriormente comentados., [CA] Actualment, mentre el nombre de serveis GNSS disponibles augmenta, cal avaluar amb dades reals les millores que ofereixen els nous productes de posicionament, i quin és el seu acompliment i evolució respecte dels seus serveis antecessors i el dels seus competidors. Entre els serveis de posicionament emergents, resulta d'especial interès el proporcionat per la constel·lació Europea de GALILEO, la qual està a prop d'arribar a la seva completa capacitat operacional, i que resulta prometedora quant als seus requisits de prestacions a nivell usuari, que poden obtenir-se mitjançant l'ús dels senyals del seu servei obert: E1, E5a i E5b. D'entre els sistemes ja existents, el més destacat és el proporcionat per la constel·lació Nord-americana de GPS, el qual ha estat permetent amb el senyal C / A un servei de posicionament estàndard i un servei de posicionament precís amb el senyal P per a fins militars. A més a les evolucions del sistema GPS planegen transmetre un servei civil amb senyals més robustes, com pot ser la L5. L'objectiu d'aquest treball és comparar els serveis oberts de posicionament de les constel·lacions de GPS i GALILEO, mitjançant l'anàlisi de les seves prestacions de precisió i integritat obtingudes d'una campanya d'observació, on les dades de referència a utilitzar són la xarxa d'estacions del IGS. La metodologia de posicionament a implementar és el post-processat d'observables de pseudo-rang mono-freqüència en manera estàtica. Per assolir aquest objectiu, l'esforç principal estarà enfocat en el desenvolupament d'una eina SW totalment configura-ble per l'usuari, que sigui capaç de processar els observables de pseudo-rang proporcionats pel marc de referència espacial que formen els satèl·lits de GPS i GALILEO, per posteriorment obtenir les posicions del receptor per mitjà d'un algoritme d'estimació per mínims quadrats. Els resultats que s'obtinguin d'aquest processament seran transmesos a altres eines d'anàlisi, les quals es desenvoluparan també en el marc d'aquest projecte, amb la finalitat de resumir i presentar de manera gràfica les prestacions obtingudes de la campanya. Finalment, amb el suport d'aquests resultats, s'exposaran les conclusions sobre l'acompliment i l'evolució dels serveis anteriorment comentats.

Since the introduction of the Android 7 in August 2016, it has become possible to use raw data collected by GNSS sensors present in some Android smartphones and tablets. Therefore, it became possible, for the first time, to perform the post-processing of the data, which means to obtain coordinates that are more accurate than usual, from meters to decimeters. In addition, among the technological innovations in the context of positioning via smartphones, it is mentioned the use of modern GNSS sensors, like the one used by Xiaomi Mi 8, which was the first smartphone to integrate a dual-frequency GNSS sensor. In this research, data collection campaigns were carried out in static mode to evaluate the quality of geodetic coordinates obtained from Mi 8. Using freely available applications that store raw data in files in RINEX format, the data was post-processed with different positioning methods and with different software, including the freely available IBGE-PPP online service in Brazil. The results of this research show that it is possible to obtain geodetic coordinates with an accuracy at decimeter order, which indicates that the methodology can be used in some engineering applications. Resumo: Desde a introdução do Android 7 em agosto de 2016, tornou-se possível usar dados brutos coletados por sensores GNSS presentes em alguns smartphones e tablets Android. Com isso, torna-se possível, pela primeira vez, realizar o pós-processamento dos dados, o que significa obter coordenadas mais acuradas do que o normal, de metros a decímetros. Além disso, entre as inovações tecnológicas no contexto de posicionamento via smartphones, cita-se a utilização de sensores GNSS modernos, como o utilizado pelo Xiaomi Mi 8, que foi o primeiro smartphone a integrar um sensor GNSS de dupla frequência. Nesta pesquisa, campanhas de coleta de dados foram realizadas em modo estático para avaliar a qualidade das coordenadas geodésicas obtidas a partir do Mi 8. Usando aplicativos disponíveis gratuitamente que armazenam dados brutos em arquivos no formato RINEX, os dados foram pós-processados com diferentes métodos de posicionamento e com diferentes softwares, incluindo o serviço online IBGE-PPP disponível gratuitamente no Brasil. Os resultados desta pesquisa mostram que é possível obter coordenadas geodésicas com acurácia na ordem decimétrica, o que indica que a metodologia pode ser utilizada em algumas aplicações de engenharia.

[EN] Global Navigation Satellite System (GNSS) interferometric reflectometry, also known as the GNSS-IR, uses data from geodetic-quality GNSS antennas to extract information about the environment surrounding the antenna. Soil moisture moni-toring is one of the most important applications of the GNSS-IR technique. This manuscript presents the main ideas and implementation decisions needed to write the Python code for software tools that transform RINEX format observation and navigation files into an appropriate format for GNSS-IR (which includes the SNR observations and the azimuth and elevation of the satellites) and to determine the reflection height and the adjusted phase and amplitude values of the interferometric wave for each individual satellite track. The main goal of the manuscript is to share the software with the scientific com-munity to introduce new users to the GNSS-IR technique., The authors want to thank the staff of the Cajamar Center of Experiences, and especially Carlos Baixauli, for their support and collaboration in the Paiporta experiment. The authors also want to thank Alfred Leick and Steve Hilla for their valuable comments and suggestions.

A new design concept of a compact satellite antenna module for automotive application is presented, enabling mobile reception of all common Global Navigation Satellite Systems (GNSS), e.g. GPS in L1 and L2 bands, Galileo, GLONASS, BeiDou, as well as reception of Satellite Digital Audio Radio Services (SDARS). The design concept is based on the combination of a dual-band ring structure for GNSS with a single-band ring structure for SDARS which allows easy fabrication in combination with high reception properties. The performance of the antenna module and its fulfilment of the requirements of car manufacturers and service providers is proven by simulated and measured results, showing the high realised gain for circular polarisation, efficiency, matching and decoupling against terrestrial interferers.

High precision Global Navigation Satellite Systems (GNSS) positioning and time transfer require correcting signal delays, in particular higher-order ionospheric (I2+) terms. We present a consolidated model to correct second- and third-order terms, geometric bending and differential STEC bending effects in GNSS data. The model has been implemented in an online service correcting observations from submitted RINEX files for I2+ effects. We performed GNSS data processing with and without including I2+ corrections, in order to investigate the impact of I2+ corrections on GNSS products. We selected three time periods representing different ionospheric conditions. We used GPS and GLONASS observations from a global network and two regional networks in Poland and Brazil. We estimated satellite orbits, satellite clock corrections, Earth rotation parameters, troposphere delays, horizontal gradients, and receiver positions using a global GNSS solution, Real-Time Kinematic (RTK) and Precise Point Positioning (PPP) techniques. The satellite-related products captured most of the impact of I2+ corrections, with the magnitude up to 2 cm for clock corrections, 1 cm for the along- and cross-track orbit components, and below 5 mm for the radial component. The impact of I2+ on troposphere products turned out to be insignificant in general. I2+ corrections had limited influence on the performance of ambiguity resolution and the reliability of RTK positioning. Finally, we found that I2+ corrections caused a systematic shift in the coordinate domain that was time- and region-dependent, and reached up to -11 mm for the North component of the Brazilian stations during the most active ionospheric conditions. .

On September 30, 2009, an Mw7.6 earthquake hit the west coast of Sumatra. This main shock caused the crustal deformation affecting a wide area in the western part of Sumatra. This paper presents the analysis of the deformation recorded by the Sumatran GPS Array (SuGAr) network. More than 40 GPS stations were installed to continuously monitor the deformation in Sumatra, among 12 of them is known to have been deformed by this earthquake. We processed whole data in 2009 to understand the dynamics of western part of Sumatra before, during and after the earthquake. Relative daily position data is obtained from postprocessing with GAMIT/GLOBK software, implementing the DGPS technique to estimate daily position from GPS RINEX data. GPS measurements shows that during the earthquake, most stations in Mentawai is deformed toward the southwest direction, varies from 8 – 50 mm, and the stations in mainland Sumatra is deformed toward various direction, varies from 5 – 28 mm. There is no anomaly and strange behaviour before the event as the precursor, and the deformation trend one day after the events seems to return to the preseismic pattern.

Graphical abstract, A computational algorithm is developed for estimating accurately the attitude of a robotic arm which moves along a predetermined path. This algorithm requires preliminary input data obtained in the static mode to yield phase observables for the precise, 3-axis attitude determination of a swinging manipulator in the dynamic mode. Measurements are recorded simultaneously by three GPS L1 receivers and then processed in several steps to accomplish this task. First, artkconv batch executable converts GPS receiver readings into RINEX format to generate GPS observables and ephemeris for multiple satellites. Then baseline vectors determination is carried out by baseline constrained Least-Squares Ambiguity Decorrelation (LAMBDA) method that uses double difference carrier phase estimates as input to calculate integer solution for each baseline. Finally, attitude determination is made by employing alternatively Least-squares attitude determination (LSAD) in the static mode and extended Kalman filter in the dynamic mode. The algorithm presented in this paper is applied to recorded data on Mitsubishi RV-M1 robotic arm in order to produce attitude estimates. These results are confirmed by another set of Euler angles independently evaluated from robotic arm postures obtained along the predefined trajectory.

This study verifies the performance of the ionosphere-free L1 pseudorange for dual-frequency space-based augmentation systems (SBAS) users by both of theoretical analysis and experiments with actual GPS data. Although the dual-frequency pseudorange from ionosphere-free linear combinations is commonly used as a standard method, the ionosphere-free L1 range based on the weighted Hatch filter has advantages in terms of the amplification factor caused by a dual-frequency combination and filter weights optimised by the least-squares method. For the experimental analysis, RINEX data were collected from five National Geographic Information Institute reference stations on the Korean peninsula and used to generate an SBAS correction message following international SBAS specifications. The experimental results show that using the proposed method results in a 29% improvement in the range domain compared with the use of a traditional ionosphere-free linear combination filter. In the position domain, the proposed method shows a horizontal accuracy improvement of 16% after the application of post-processed SBAS orbit/clock corrections w.r.t. the traditional filter. Finally, this study also demonstrates that the accuracy of dual-frequency users can surpass than that of single-frequency SBAS users only if corrections are estimated with ionospheric delay-free measurements in the master station as well.

We present a new technique for estimating the absolute vertical and slant total electron content (TEC). The estimation is based on single-frequency joint phase and pseudorange GPS/GLONASS measurements at single stations. Estimated single-frequency vertical TEC agrees qualitatively and quantitatively with the dual-frequency vertical TEC. For analyzed stations a typical value of the difference between the single-frequency vertical TEC and dual-frequency ones generally does not exceed ~1.5 TECU with RMS up to ~3 TECU.

The usability and the accuracy of internet-based position determination services which have gained importance in recent years is one of the up-to-date subjects of studies. Online processing services have more advantages than commercial and scientific software; since they are easy to use, require less experience and free because they get quick results. In this study, GPS observation files in rinex format belonging to 6 stations were evaluated using Auspos, Magic-GNSS and Opus services then the results were obtained. Three systems showed the similar results for the results obtained according to 24-hour measurement period. In the second study, observation files were divided into 12, 6 and 2 hour groups and after the results were obtained they were compared to 24-hour results. According to the reports, it was seen that the accuracy decreased as the observation period got shorter. In all three systems, 24 and 12-hour observation accuracy occurs in cm measures. In 6 and 2 hour periods where the observation period is shorter, accuracy value reaches to 3-4 cm. According to these results, it is seen that although it generally depends on observation period, internet-based position determination services sustain adequate accuracy for basic geodetic network application that the topographical engineering needs.

In this paper the performance of a high sensitivity GPS/GLONASS receiver mounted on CE-5T1 Service Module is studied and the data received on the first Earth-lunar transfer orbit is processed and analyzed. At least four GLONASS satellites are visible for 46% of the data span while for 98% of the data span at least four GPS satellites are visible. GLONASS serves as a necessary supplement to GPS in real time positioning whenever less than four GPS satellites are tracked, and helps to optimize the observation geometry by reducing the Position Dilution of Precision (PDOP) values by up to 77%. However, noisier GLONASS pseudorange data should be properly weighted in order not to deteriorate the positioning accuracy. Studies indicate that when the inverse square of the pseudorange measurement error of each satellite is applied as the weight value, single point positioning (SPP) accuracy improves from 57.7 m (RMS) with GPS data alone to 44.6 m (RMS) with the addition of GLONASS data. Transmitter antenna Equivalent Isotropic Radiated Power (EIRP)s of all the four blocks of GPS satellites as well as GLONASS satellites are derived from the received C/N0 data and show significant variance in sidelobe power patterns. In general, the EIRP patterns of GPS Block IIR-M and GLONASS satellite antennas have a comparatively flat power level of around 10 dB W within the off-boresight angle range of 30–80° and roll off at the off-boresight angle of about 80°, offering deep space applications greater benefits than the other three blocks of GPS satellites. In addition, an interesting close encounter happens between CE-5T1 spacecraft and GLONASS satellite R06. Investigations indicate that the PDOP value increases up to 1.4 times and the SPP accuracy deteriorates by more than 142% if satellite R06 is excluded in the positioning computation.

Within the frame of the International DORIS Service (IDS), the CNES/CLS Analysis Center contributes to the geodetic and geophysical research activity through DORIS data analysis. A strategy was developed for the processing of the measurements of the DGXX instruments in RINEX/DORIS format, as it will be the only type of DORIS format made available by CNES, starting with the Jason-3 and Sentinel-3A missions launched at the beginning of the year 2016. The purpose of this paper is to describe the method implemented in the CNES/CLS Analysis Center orbit computation software GINS to process RINEX/DORIS data files. Phase measurements are converted into Doppler counts and then into relative satellite-to-beacon velocities. In this approach, the iono-free phase centers have to be used as the end points of the measurement instead of the 2 GHz phase centers. Given that, the processing results with RINEX/DORIS data are similar to the ones obtained with the usual doris2.2 data, except the scale factor of the Terrestrial Reference Frame in the 7-parameter transform of the network solution. We also address the issue of the scale factor increase from 2012 observed by all the IDS Analysis Centers in their solutions for the ITRF2014 combination. We show that the scale increase in 2012 is dependent on the type of DORIS data used. This scale increase is also enhanced by a bias due to the inclusion of HY-2A data, but which can be eliminated by adopting different coordinates of the onboard DORIS antenna phase center.

Earlier studies performed at the Center for Orbit Determination in Europe (CODE) analysis center have revealed conspicuous signatures for certain GLONASS satellites when comparing their orbits with Satellite Laser Ranging (SLR) measurements. In this study we show that this phenomenon can be significantly reduced when using horizontal satellite antenna offsets that differ from the nominal values used by the International GNSS Service (IGS) for specific intervals and satellites. Analysis of multi-year time series shows instantaneous changes in the satellite antenna offset parameters of several centimeters in the X- and Y-component whereas the Z-component is not affected. In some cases the offsets do not agree with the nominal values during the entire lifetime of the satellite. The magnitude of the deviation may vary between 5 and 15 cm. Using these re-estimated satellite antenna offsets in the orbit determination the residuals with respect to the Satellite Laser Ranging (SLR) measurements are significantly reduced whereas the orbit misclosures for one-day arcs are too noisy to detect a positive or negative impact. It is difficult to reconstruct from the available information what actually caused the observed changes. However, changes in the carrier-to-noise density reported in the observation files in Receiver INdependent EXchange format (RINEX) by several IGS stations suggest an issue with the satellite antennas.

Denne masteroppgaven, skrevet for REALTEK ved Norges miljø- og biovitenskapelige universitet (NMBU), omhandler fagområdet geomatikk; mer spesifikt GNSS-observasjoner med en smartmobil. Hensikten med oppgaven er å analysere rådata fra en Samsung Galaxy S9+, som har kapabilitet for GNSS-måling på én frekvens for flere globale satellittnavigasjonssystemer (GNSS). Målinger fra nærliggende basestasjon ble også brukt i analysen av mobilobservasjonene. Oppgaven fokuseres hovedsakelig på GPS-observasjoner, men noen resultater for Galileo og andre GNSS blir også presentert. Analysen ble hovedsakelig utført vha. programmering ved bruk av Python 3.7. Oppgaven består hovedsakelig av seks hovedkapitler, og i tillegg noen vedlegg. Kap. 1 Introduksjon: Historikk rundt temaet mobil GNSS, problemstillinger, motivasjon, forklaringer og tidligere, relevant forskning. Kap. 2 Teori: Relevant teori for oppgaven; formler, illustrasjoner og forklaringer. Kap 3 Datainnsamling og metode: Beskrivelse av hvordan rådata ble anskaffet i praksis, og hvordan disse ble analysert. Kap. 4 Resultater: Plott og tabeller som resulterte fra analyse av rådata. Kap. 5 Diskusjon: Tolkning av resultater og generell refleksjon rundt oppgaven. Kap 6. Konklusjon: Endelige svar på oppgavens problemstillinger og forslag til videre arbeid rundt temaet. Først i oppgaven presenteres den moderne mobilen og hvordan den har utviklet seg blant allmennheten. Mobiltelefonen var først forbeholdt kommunikasjonsformål, men med tiden har mer og mer teknologi blitt implementert i den lommestore enheten: Bilder, video og – sist, men ikke minst – GPS. Den første GPS-støttende mobilen kom ut i 1999, og siden den tid har satellittbasert navigasjonsteknologi blitt en standard for mobiltelefonen. I 2019, tjue år senere, er det ikke lenger så mye snakk om GPS alene, men heller GNSS (Global Navigation Satellite Systems) – flere satellittbaserte navigasjonssystemer. Forventningene våre til mobilens navigasjonsteknologi har blitt større, men har kvaliteten på målingene – og posisjoneringen – blitt noe bedre? Tidligere har det blant annet blitt forsket på GNSS rådata fra en Nexus 9-tablett (Håkansson, 2018) og en Huawei P10 (Lachapelle et al., 2018). For Nexus 9 ble det oppnådd flytløsninger med statisk måling som resulterte i 3D-presisjoner over 40 cm. Fra tilsvarende resultater for Huawei P10 ble det konkludert at kontinuerlig fasemåling var "dårlig i de fleste tilfeller" (ibid.). Med nye utviklerinnstillinger i Android 9 har derimot kontinuerlig fasemåling blitt forbedret: Det er nå mulig å skru av GNSS-relaterte driftssykluser som tidligere har skapt fasebrudd. For anskaffelse av data i oppgaven ble det målt to individuelle punkter; AUDM og STRB, i tidsintervaller på to timer hver. AUDM befinner seg blant bygninger og en stor vannflate, mens STRB står på en øde fotballbane. Punktene ble med hensikt plassert i disse omgivelsene slik at det ene punktet ble mer utsatt for multipath enn det andre. Etter måling ble rådataene analysert og prosessert: Python 3.7 ble brukt til analysering og plotting, mens RTKLIB og SKTrans henholdsvis ble brukt til punktprosessering og -transformering. Plott og tabeller viser resultatene fra målingene. Antall satellitter målt fra viste seg å være over 30; ofte rundt 10 for GPS og GLONASS, og 3-6 for Galileo. GPS-satellittenes baner blir også visualisert ved bruk av himmelplott. Støyen på koden hos mobilen er, som ventet, langt høyere enn den hos geodetisk mottaker. Videre resulterer punktestimater fra koden på flere meter i presisjon og nøyaktighet, mens fasemålingene ga presisjonsmål på godt under centimeteren. Fasebrudd opptrådde flere ganger i måleintervallene, men det var mulig å opprettholde heltallsflertydighetene over lenger tidsintervaller. Dette resulterte i statiske fix-løsninger med 3D-presisjon på under 5 mm for punktene AUDM og STRB. Dette var et uventet bra resultat, og det kan muligens bli bedre – fasesenteret bør blant annet bestemmes. Det kan forventes en romlig presisjon på 10-20 meter ved prosessering av støyete kodemålinger. Høydekomponenten blir som forventet dårligst. Inkludering av Galileo forbedrer kodeløsningen noe. Videre kan midling av kodebestemte punkter gi en nøyaktighet på 1.5 og 3 meter i grunnriss og høyde, respektivt. For fix-løsninger med statisk måling ble resultatet over all forventning: En romlig presisjon på under 5 mm kan oppnås med mobilens fasemålinger. Fix-løsningene bommet fremdeles på selve punktet med ca. 6 cm nord og 3-4 cm vest, men dette skyldes først og fremst at mobilens fasesenter er ukjent. PCO kan tilnærmes ved å utføre veldig nøyaktige, statiske målinger – mulig ved høy presisjon. Resultatene oppnådd i denne oppgaven virker lovende for mobilbasert GNSS i fremtiden. This master thesis, written for REALTEK at the Norwegian University of Life Sciences (NMBU), deals with the field of study that is geomatics; more specifically GNSS observations from a smartphone. The purpose of this thesis is to analyze raw measurements from a Samsung Galaxy S9+, which has the capability to measure on one frequency for multiple global navigation satellite systems (GNSS). Measurements from a nearby base station were also used in the analysis of the smartphone observations. The thesis focuses mainly on GPS observations but some results from Galileo and other GNSS are also presented. The analysis part was mainly accomplished by programming in Python 3.7. The study consists of six main chapters, but also some appendices. Chp. 1 Introduction: Some history concerning mobile GNSS, issues for the thesis, motivation, explanations and former studies on the topic. Chp. 2 Theory: Relevant theory for the thesis; formulas, illustrations and explanations. Chp. 3 Data acquisition and method: Explanations on how the raw measurements were obtained, practically, and how they were analyzed. Chp. 4 Results: Plots and tables as products from the analysis. Chp. 5 Discussion: Interpretations of the results and general reflections on the thesis. Chp. 6: Conclusion: Final answers on the issues raised in the thesis, and proposals on relevant fields to study. Firstly, the thesis presents the modern cellphone and how it has developed among people in general. The mobile phone was mainly reserved for communication purposes, but with time, more and more technology has been implemented in the pocket-sized device: Pictures, video and – finally – GPS. The first GPS-supporting cellphone was launched in 1999, and since then, satellite-based navigation technology has become a standard in cellphones. In 2019, twenty years later, we are not only interested in GPS alone, but rather GNSS – multiple satellite-based navigation systems. Our expectations regarding mobile-based navigation technology have become bigger, but has the quality of the measurements – and the positioning – become any better? Other related field studies include research on GNSS raw measurements from a Nexus 9 tablet (Håkansson, 2018) and a Huawei P10 (Lachapelle et al., 2018). For a Nexus 9, float solutions from static measurements were achieved, resulting in precisions above 40 cm. From similar results for Huawei P10, it was concluded that “carrier phase measurement continuity was poor in most instances” (ibid.). However, with newly available developer settings in Android 9, continuous phase-measuring has been improved: GNSS-related duty-cycling, which was the main cause of cycle slips in the past, can now be turned off. For the data acquisition in the thesis, two points were measured; AUDM and STRB, over the span of two hours each. AUDM is located among some buildings and next to a water surface, while STRB is situated on an open soccer field. The points were placed in these environments on purpose, so that one point is more exposed to multipath than the other. After data acquisition, the data were analyzed and processed: Python 3.7 was used for analyzing and plotting, while RTKLIB and SKTrans were respectively used for point-processing and transformation. Plots and tables show the results from the measurements. The total number of satellites synced can reach over 30; often 10 GPS and GLONASS satellites, and 3-6 Galileo satellites. GPS orbits are also visualized by a sky plot. The smartphone code noise is, as expected, far greater than that of a geodetic receiver. Further, estimates from the code resulted in precisions in the meter range, while static carrier phase measurements resulted in sub-centimeter precision. Cycle slips appeared in multiple instances during measurements, however, multiple fix amibiguities were maintained for longer periods of time. This resulted in static fix solutions with 3D precisions below 5 mm for the points AUDM and STRB. These were unexpectedly good results, and they can probably be improved – the PCO should be estimated. A spatial precision of approximately 10-20 meters can be expected from the noisy code estimates. The height estimate is worst, as expected. The inclusion of Galileo improves the code estimates to an extent. Further, by averaging multiple code estimates, a horizontal and vertical accuracy of about 1.5 and 3 meters can be achieved, respectively. For static estimates, the results went beyond all expectations: A spatial precision below 5 mm can be achieved from the smartphone phase measurements. The accuracy is still off by some centimeters, mostly due to the unknown PCO. M-GEOM