Precise Point Positioning Research Articles

Distributed satellite system autonomous orbital control with recursive filtering

In this article, we propose a recursive orbital elements filter for autonomous control of Distributed Satellite Systems (DSS) that significantly reduces the variance of relative orbital elements between the observed and the desired satellite orbits. Leveraging satellite kinematics and control inputs data, combined with a model of relative dynamics, the filter provides smooth and continuous orbital control, while minimizing propellant consumption. In conjunction with Precise Point Positioning (PPP) navigation, the proposed filter enables onboard continuous low-thrust control compatible with high-performance electric propulsion. We also propose a restricted transverse/normal control law that simplifies the thruster's configurations and/or attitude manoeuvres required for propulsion pointing. The applicability and validity of our proposed techniques are verified by numerical simulations with two case studies: a constellation for Differential Interferometric Synthetic Aperture Radar (DInSAR) for global infrastructure monitoring; and a maritime domain awareness mission based on along-track interferometric synthetic aperture radar which requires single-pass interferometry for responsive ship traffic surveillance, and the coverage of a very large maritime zone with high revisit rates.

Performance of kinematic GPS PPP AR under different ionospheric scintillation conditions

To analyze the performance of Global Positioning System (GPS) Precise Point Positioning (PPP) Ambiguity Resolution (AR) under various ionospheric scintillation environments, we selected GPS data of ionospheric scintillation monitoring receivers (ISMR) and geodetic receivers from high-latitude and low-latitude regions during 2021–2023. We conducted GPS Kinematic PPP using Canadian Spatial Reference System (CSRS) PPP and used the maximum and average values of σφ and S4 as indicators to characterize the intensity of phase scintillation and amplitude scintillation for ISMRs, while the maximum and average values of Rate of Total Electron Content Index (ROTI) to characterize the intensity of ionospheric scintillation for geodetic receivers. We also used ambiguity resolved percentage (ARP) and the 3-Dimensional Root Mean Square (3D RMS) of positioning errors as performance metrics for PPP-AR and PPP. As the maximum and average values of ionospheric scintillation indices increase, the PPP-ARP for high-latitude ISMRs decreases to 90.0 %, and the 3D RMS can reach 0.204 m. During ionospheric quiet conditions, positioning accuracy of GPS PPP can reach the cm-mm level. As the geomagnetic latitude decreases, the scintillation effects on PPP-AR and PPP become more pronounced for high-latitude ISMRs. Compared with high-latitudes, ISMRs located at low-latitudes are more severely affected by scintillation, with PPP-ARP at the station HNLW in China and the station UFBA in Brazil dropping to 80.0 % and 60.0 %, respectively. The 3D RMS can reach 0.288 m and 0.341 m. The results of geodetic receives are consistent with those of ISMRs, with 3D RMS of positioning errors up to 0.240 m and 0.256 m for CYNE and MAL2, respectively, while PPP-ARP drops to 60.4 % and 79.6 %. Additionally, we observed a strong positive correlation between ionospheric scintillation duration and the maximum values of σφ, S4 and ROTI.

A flexible method for BDS-3 multi-frequency phase observable-specific biases estimation and its PPP analysis with different ambiguity resolution strategies

With the rapid progress of Global Navigation Satellite Systems (GNSS), integer ambiguity resolution has gradually become one of the key factors that affecting Precise Point Positioning (PPP) to achieve high-precision positioning results and fast convergence. Fortunately, the proposal of observable-specific code/phase biases (OSB) has greatly alleviated this problem tremendously. Different from obtaining OSB by dual-frequency linear combinations, this research proposed BeiDou Navigation Satellite System (BDS) OSB estimation method from raw observations. This method allows for more flexible estimation in a global network, without the need to compose the complex linear combinations when involving multi-frequency measurements processing. The BDS-3 observation data collected from 112 stations over one month (October 2022), containing B1C/B1I/B2a/B2b/B3I frequencies, were used for five-frequency phase OSBs estimation. Subsequently, static and kinematic PPP were executed utilizing two different ambiguity resolution strategies to corroborate the efficacy of this method. The results revealed that the BDS-3 five-frequency phase OSBs possessed good monthly stability, with standard deviation less than 0.3 cycle. High position accuracy was achieved in the static mode by fixing the ambiguity directly, with root mean square (RMS) of 3.0, 4.8 and 9.9 mm. Meanwhile, the ambiguity fixed rate was maintained at a high level around 96 % in multi-frequency tests. Simultaneously, the kinematic mode also presented the centimeter-level dynamic positioning results and the positioning accuracy improved by 55, 31 and 17 % in the East, North and Up components, respectively. Compared to the float solutions, the adoption of multi-frequency OSBs significantly accelerated the convergence speed by 55 % on average.

Analysis Of Multi-Constellation Using Precise Point Positioning Technique (PPP) With Mobile Phone As Receiver For Coordinate Accuracy

Global Navigation Satellite Systems (GNSS) are vital for navigation. This study compared the productivity and accuracy of surveys using different GNSS constellation combinations: GPS-only, GPS+GLONASS, and GPS+GLONASS+Beidou. Instead of costly RTK receivers, an Android phone with Geo++ RINEX and Locus Map Apps served as the receiver. Precise Point Positioning (PPP) was adopted for accurate positioning without a base station. The study was conducted at Nile University Abuja with ten stations, considering various conditions and obstructions. Data collected from the Geo++ RINEX app were analyzed using RTKLIB. Results were evaluated using RTKLIB and Microsoft Excel for position and altitude accuracy. Position readings were generally accurate, while altitude measurements exhibited disparities. When combining GPS, GLONASS, and Beidou constellations, the maximum and minimum numbers of serving satellites were 32 and 26, respectively. The closest altitude reading had a 1-meter difference, while the highest disparity in altitude measurement reached 20.9 meters.

SEAMLESS PRECISE KINEMATIC POSITIONING IN THE HIGH-LATITUDE ENVIRONMENTS: CASE STUDY IN THE ANTARCTIC REGION

Scientific activities in the Antarctic regions have increased daily within the last decades to achieve many different projects. The ice sheet over 98% of the Antarctic continent, the coldest, driest, and windiest place in the world and has the largest desert, makes it very difficult to conduct any kind of study and research. Among them, precise hydrographic surveying should be conducted for many different applications that require reliable and accurate positioning. The output from these surveys plays a vital role in understanding sea level changes, global warming, sea ice movement, navigation and many others. The harsh atmospheric and topographic conditions of the region pose additional challenges to surveyors in the use of conventional terrestrial measurement techniques and satellite-based positioning methods (GNSS) to make positioning. Low quality and noisy GNSS observations with low satellite elevations made their positioning vulnerable to cycle slip, multipath, and discontinuity in Antarctica. This study analyses the performance of the post-processed kinematic Precise Point Positioning (PPP) based on the web-based online GNSS processing service for marine surveying in the high-latitude environment. Within this frame, two realistic experiments were carried out on a ship and zodiac boat during the 6th Turkish Antarctic Expedition (TAE). The results show that the PPP coordinates using an online GNSS processing service provide kinematic positioning with centimetre level of accuracy using a single GNSS receiver. The general results showed that the PPP technique allows for much faster and accurate positioning in remote and high-latitude areas at a lower cost.

Real-time retrieval of high-precision ZTD maps using GNSS observation

Zenith Tropospheric Delay (ZTD) is an important factor that restricts the high-precision positioning of global navigation satellite system (GNSS), and it is of great significance in establishing a real-time and high-precision ZTD model. However, existing ZTD models only consider the impact of linear terms on ZTD estimation, whereas the nonlinear factors have rarely been investigated before and thus become the focus of this study. A real-time and high-precision ZTD model for large height difference area is proposed by considering the linear and nonlinear characteristics of ZTD spatiotemporal variations and is called the real-time linear and nonlinearity ZTD (RLNZ) model. This model uses the ZTD estimated from the Global Pressure and Temperature 3 (GPT3) model as the initial value. The linear impacts of periodic term and height on the estimation of ZTD difference between GNSS and GPT3 model is first considered. In addition, nonlinear factors such as geographical location and time are further used to fit the remaining nonlinear ZTD residuals using the general regression neural network method. Finally, the RLNZ-derived ZTD is obtained at an arbitrary location. The western United States, with height difference ranging from −500 to 4000 m, is selected, and the hourly ZTD of 484 GNSS stations provided by the Nevada Geodetic Laboratory (NGL) and the data of 9 radiosonde (RS) stations in the year 2021 are used. Experiment results show that a better performance of ZTD estimation can be retrieved from the proposed RLNZ model when compared with the GPT3 model. Statistical results show the averaged root mean square (RMS), Bias, and mean absolute error (MAE) of ZTD from GPT3 and RLNZ models are 33.7/0.8/25.7 mm and 22.6/0.1/17.4 mm, respectively. The average improvement rate of the RLNZ model is 33 % when compared to the GPT3 model. Finally, the application of the proposed RLNZ model in simulated real-time Precise Point Positioning (PPP) indicates that the accuracy of PPP in N, E and U components is improved by 8 %, 2 %, and 6 % when compared with that from the GPT3-based PPP. Meanwhile, the convergence time in N and U components is improved by 23 % and 7 %, respectively. Such results verify the superiority of the proposed RLNZ model in retrieving real-time ZTD maps for GNSS positioning and navigation applications.

Assessment of Positioning with IGS02 and IGS03 Real Time Service Data Compared to Long Convergence Static-PPP in Gwagwalada, Abuja, Nigeria.

The persistent challenges being faced daily on the downtimes and completely data outages of Continuously Operating Reference Stations (CORS) is becoming worrisome and also the unavailability of GNSS control points around local regions where access to CORS is also difficult or unavailable in developing countries, such as Nigeria, has become a major challenge to accurate positioning by differential GNSS method. Also, acquisition of two units of dual frequency GNSS receivers is as well becoming too costly and unaffordable for users due to economic downturn. With the advent of International GNSS Service (IGS) – real-time service (IGS-RTS) which provides corrections that can be applied in real time, precise point positioning (PPP) with just a receiver unit has recently given a relief. The purpose of this study was to assess the positioning with IGS02 and IGS03 Real Time Service data stream compared to long convergence Static-PPP in Gwagwalada, Abuja, Nigeria. The study determined the GNSS Static observations (minimum of three hours per session) on the chosen stations as reference, determination of the IGS-RTS data observations using RTKLIB software; and also observations were done with IGS-RTS data stream of IGS02 and IGS03 and statistical tests were performed. The GNSS Static coordinates and IGS-RTS coordinates were compared and analyzed. The results show the Root Mean Square (RMS) discrepancy of IGS02 and IGS03 observations, as was compared to the Static-PPP, the results fell within 0.065(m) and 0.028(m) respectively. This result indicates that IGS03 yields better performances in term of accuracy.

BDS/GPS Zenith Tropospheric Delay Estimation and Its Effect on Precise Point Positioning

BDS/GPS Zenith Tropospheric Delay Estimation and Its Effect on Precise Point Positioning

Low orbit regional enhanced navigation constellation for BDS3 design based on Bayesian optimization algorithm

The application of Low Earth Orbit (LEO) satellite navigation can enhance geometric structure, increase observations and contribute to navigation and positioning. To improve the performance of the navigation constellation in China, this study proposes an optimized method of LEO-enhanced navigation constellation for BDS based on Bayesian optimization algorithm. In this paper, four different optimal LEO constellation configurations are designed, and their enhancements to BDS3 navigation performance are analyzed, including Geometric Dilution of Precision (GDOP), the numbers of visible satellites, and the rapid convergence of precision point positioning (PPP). Additionally, the enhancement advantages in China compared to other regions are further discussed. The results demonstrate that regional enhanced constellations with 70, 72, 80, and 81 satellites at an altitude of 1000 km can significantly improve the navigation performance of the navigation constellation. Globally, the addition of optimized LEO constellations has reduced the hybrid constellation GDOP by 19.0 %, 18.3 %, 19.9 %, and 20.3 %. Similar results can be obtained using the genetic algorithm (GA), but the computational efficiency of Bayesian optimization algorithm is 53.9 % higher than that of the genetic algorithm. The number of visible satellites of enhanced constellations in China has increased by more than four on average, which is better than that in other regions. In the PPP experiment, the convergence time of the stations in China and other regions is shortened by 83.0 % and 76.2 %, respectively, and the navigation performance of hybrid constellations in China is better.

Evaluation of precise point positioning and post-processing kinematic methods for tide measurement in hydrographic surveys

Evaluation of precise point positioning and post-processing kinematic methods for tide measurement in hydrographic surveys

An Interstation Undifferenced Real-Time Time Transfer Method with Refined Modeling of Receiver Clock

Due to their advantages of high measurement accuracy and wide coverage, global navigation satellite systems (GNSSs) can carry out long-distance time transfers, among which the precise point positioning (PPP) method is widely used. However, the accuracy and stability of PPP real-time time transfer are restricted by the real-time satellite clock offset products. In addition, the receiver clock offset is usually estimated using the white noise model, which ignores the correlation of the clock offsets between adjacent epochs and the stability of the atomic clock itself. In order to obtain higher performance time transfer results, we propose an interstation undifferenced time transfer method with refined modeling of the receiver clock. This method takes the satellite clock offset as the parameter to be estimated, which can avoid the influence of external satellite clock offset products. In addition, the refined modeling of the receiver clock can improve the strength of the model and the accuracy of time transfer. Based on the ultrarapid satellite orbit products provided by the International GNSS Service (IGS), time transfer experiments are carried out using data from IGS observatories and self-collected data. The results show that sub-nanosecond accuracy can be achieved in real-time time transfer using this method. Compared with the traditional PPP model, the accuracies of the four time links are increased by 88.4%, 92.9%, 88.6%, and 74.5%, respectively, and the stability is increased by approximately 66.4% on average. Moreover, after applying the clock offset constraint model, frequency stability is further improved, in which the short-term stability is improved significantly, with a maximum of 86.9% and an average improvement of approximately 66.8%.

A Statistical Approach for the Integration of Multi-Temporal InSAR and GNSS-PPP Ground Deformation Measurements.

Determining and monitoring ground deformations is critical for hazard management studies, especially in megacities, and these studies might help prevent future disaster conditions and save many lives. In recent years, the Golden Horn, located in the southeast of the European part of Istanbul within a UNESCO-protected region, has experienced significant changes and regional deformations linked to rapid population growth, infrastructure work, and tramway construction. In this study, we used Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS) techniques to investigate the ground deformations along the Golden Horn coastlines. The investigated periods are between 2015 and 2020 and 2017 and 2020 for InSAR and GNSS, respectively. For the InSAR analyses, we used sequences of multi-temporal synthetic aperture radar (SAR) images collected by the Sentinel-1 and ALOS-2 satellites. The ground displacement products (i.e., time series and velocity maps) were then cross-compared with those achievable using the Precise Point Positioning (PPP) technique for the GNSS solutions, which can provide precise positions with a single receiver. In the proposed analysis, we compared the ground displacement velocities obtained by both methods by computing the standard deviations of the difference between the relevant observations considering a weighted least square estimation procedure. Additionally, we identified five circle buffers with different radii ranging between 50 m and 250 m for selecting the most appropriate coherent points to conduct the cross-comparison analysis. Moreover, a vertical displacement rate map was produced. The comparison of the vertical ground velocities derived from PPP and InSAR demonstrates that the PPP technique is valuable. For the coherent stations, the vertical displacement rates vary between -4.86 mm/yr and -23.58 mm/yr and -9.50 and -27.77 mm/yr for InSAR and GNSS, respectively.

GEODETIC EVIDENCE FOR POST-SEISMIC DEFORMATIONS FOLLOWING THE 2014 NORTH AEGEAN MW 6.9 EARTHQUAKE

The 2014 North Aegean Sea earthquake was a strong (Mw 6.9) event that caused significant crustal deformations. In the present study we investigate the long-term impact of the earthquake on the kinematics of the North Aegean Trough (NAT). For this purpose, we analyzed GPS observations collected from May 2010 to April 2022 at five permanent GPS reference stations. Two of these stations are located close to the epicenter(s) on the Islands of Lemnos and Samothrace. We processed the data using the Precise Point Positioning (PPP) technique. The analysis of the obtained coordinate time-series revealed a post-seismic deformation (PSD) period lasting for more than two years leading to cumulative 2D post-seismic displacement of 22 mm and 27 mm for Samothrace and Lemnos, respectively. The magnitudes of these post-seismic slip vectors correspond to 23% and 49% of the co-seismic vectors at Samothrace and Lemnos, respectively. The long-term analysis showed that after the end of the PSD period the stations are characterized by stable velocities that are noticeably different compared to the velocities prior to the event. We observed a change in the velocity in the order of 2 mm/yr for both Samothrace and Lemnos. It is the first time that PSD and velocity changes have been reported for the 2014 North Aegean Sea earthquake shedding light on the characteristics and the impact of this important earthquake on the kinematics of NAT.

Assessment of Multi-GNSS RT-PPP Services for the Antarctic Region

The international service that ensures access to data and products of global navigation satellite systems (GNSSs), known as the IGS, runs a real-time service (RTS) project to support users who need real-time access to precise products. Thanks to the RTS project, it is now possible to obtain real-time precise point positioning (RT-PPP) solutions. RT-PPP can be used in many real-time positioning applications that require a high level of accuracy, efficiency, and flexibility, including earth sciences, atmosphere sciences, marine sciences, natural hazards, and many more. In this study, we tested the impact of different worldwide RTS products and satellite configurations on the performance of RT-PPP accuracy, as well as convergence time, in the Antarctic’s challenging environment and extreme atmospheric conditions. We applied RT-PPP solutions using real-time precise products (satellite orbit/clock corrections, and biases to conduct the real-time PPP) provided by the IGS and NAVCAST (a real-time PPP positioning service) based on different GNSS constellations: GPS-only, Galileo-only, and a combination of GPS and Galileo. In this way, the performance of two different real-time (RT) services was compared with each other. At the same time, the effectiveness of the Galileo global navigation satellite system for RT-PPP was also tested, and the Galileo system’s contribution to the GPS-only RT-PPP solution was investigated. The PPP-WIZARD software was used to process the corrections and GNSS data from a reference station in the Antarctic region. Although GPS-only, Galileo-only, and multi-GNSS solutions obtained from both RT services were found to have very close accuracy to each other, the combination of the GPS and Galileo systems produced better accuracy than when using the GPS system alone. According to the numerical results of this study, it was concluded that the real-time PPP technique gave promising results in such a challenging environment of the Antarctic region. However, we also observe that the RT-PPP technique requires a stable and robust internet connection, which might limit its usefulness in remote regions. Overall, we found the RT-PPP technique to be a viable alternative to conventional relative GNSS positioning techniques, especially in areas where continuously operating reference networks or similar networks are lacking.

Testing Galileo High-Accuracy Service (HAS) in Marine Operations

Global Navigation Satellite System (GNSS) technology supports all phases of maritime navigation and serves as an integral component of the Automatic Identification System (AIS) and, by extension, Vessel Traffic Service (VTS) systems. However, the accuracy of standalone GNSS is often insufficient for specific operations. To address this limitation, various regional and local-area solutions have been developed, such as Differential GNSS (DGNSS), Satellite Based Augmentation Service (SBAS) and Real Time Kinematic (RTK) techniques. A notable development in this field is the recent introduction of the Galileo High-Accuracy Service (HAS), which saw its initial service declared operational by the European Commission (EC) on 24 January 2023. Galileo HAS provides high-accuracy Precise Point Positioning (PPP) corrections (orbits, clocks and signal biases) for Galileo and GPS, enhancing real-time positioning performance at no additional cost to users. This article presents the results of the first Galileo HAS testing campaign conducted at sea using a buoy-laying vessel temporarily equipped with a Galileo HAS User Terminal. The results presented in this Article include accuracy and position availability performance achieved using the Galileo HAS User Terminal. The article also highlights challenges posed by high-power radio-frequency interference, which likely originated from the Long-Range Identification and Tracking (LRIT) system antenna on board the vessel. Furthermore, the article provides additional assessments for different phases of navigation, demonstrating better performance in slow-motion scenarios, particularly relevant to mooring and pilotage applications. In these scenarios, values for horizontal accuracy reached 0.22 m 95% and 0.13 m 68% after removing interference periods. These results are in line with the expectations outlined in the Galileo HAS Service Definition Document (SDD).

A New Method for Deformation Monitoring of Structures by Precise Point Positioning

Although deformations are mostly insignificant, they can be catastrophic when accumulated to certain amounts. Precise point positioning (PPP) can work with one receiver, preventing problems caused by the base station constrain upon employment of current methods such as real-time kinematics (RTK). However, current methods employing PPP focus on high-frequency monitoring such as earthquake or geological calamity monitoring, and these methods are not suitable for structures. Thus, this study proposes a new method for the deformation monitoring of structures via PPP. First, we obtained the coordinate sequence of structures via static PPP when setting the interval. Then, we transformed the coordinates to the same coordinate system with the same basis. Finally, we decomposed the sequences via empirical mode decomposition (EMD) to obtain a low-frequency part, which is the deformation of the target structure. The result of the monitoring experimentation on IGS stations shows that the monitoring index, Sd, of the sequence under different intervals using this method could be 1–2 mm on average in the directions of E, N, and U, which is much better than the original monitoring sequence. Alongside that, it prevented a fall in accuracy when the interval decreased. Therefore, all results proved the feasibility and validity of the method.

ASSESSMENT OF STEC ESTIMATION QUALITY USING GNSS PPP FIXED

Abstract. GNSS (Global Navigation Satellite System) data can be used for geodetic remote sensing, particularly for monitoring the ionosphere in the context of Space Weather. One of the important parameters derived from GNSS measurements for ionospheric analysis is the Slant Total Electron Content (STEC). By utilizing GNSS data from multiple frequencies or even a single frequency, the STEC can be computed using an appropriated linear combination, like geometry free. However, when computing an ionospheric gradient between two IPP (Ionospheric Pierce Point) from the same satellite, the precision of the STEC estimate can become a limiting factor. In some cases, the uncertainty in the estimate may be greater than the actual gradient value itself. This poses challenges, especially for augmentation systems like GBAS (Ground Based Augmentation System), where accurate ionospheric gradients are crucial. An alternative approach to improve these limitations is to estimate the STEC using a different approach, like Precise Point Positioning (PPP). For such case, the coordinates of the GNSS stations are constrained to known values (PPP-Fixed), while other parameters such as clock biases, tropospheric delays, and ionospheric delays (including STEC) can be estimated. The results of an experiment carried out to assess the quality of STEC for such application are presented and have shown good results. Ionospheric gradients are agreed in the mm level.

Optimize Kalman Filter For Smart Phone Location Tracking Using GNSS Measurements

Point precise positioning (PPP) method allows to locate user with Global Navigation Satellite System under good condition. But this method is quite challenging to locate user when user is in urban areas with obstacles. Another alternative solutions such as Real Time Kinematic solve these problems with differential measurements. In real world scenario, raw GNSS measurements have usually noisy and uncertain data. Kalman filter is successful method to optimally update variables with indirect measurements. This research proposes the method to optimize Kalman filter based PPP to improve smart phone location tracking. Evaluation method showed that proposed method worked well with approximately 3.0 meter accuracy and outperformed base line model which is calculated using Weighted-Least-Square (WLS) solver.

USER IMPLEMENTATION AND ASSESSMENT OF BDS-3 PRECISE POINT POSITIONING AUGMENTATION SERVICE WITH NO ECONOMIC COST

Abstract. The satellite-based precise point positioning (PPP) service enables users with high accuracy positions without Internet connections. Currently, two types of satellite-based PPP services are available. One type is commercial service, such as Trimble CenterPoint RTX service. The second type is non-commercial and cost-free service, including the BDS-3 satellite-based PPP service based on PPP-B2b signals. This service is currently open access to all receiver manufacturers. This contribution firstly presents a detailed instruction on how to apply PPP-B2b signals into positioning. Afterwards, the performance of BDS-3 PPP service is validated with both static and kinematic experiments carried out in Wuhan, China, during day of year 168 and 172, 2022. Results indicate that PPP-B2b signals mainly improve BDS-3 clock precision and GPS orbit accuracy. With BDS-3 PPP-B2b augmentation messages, the static satellite-based PPP shows 3.9/6.9/10.3 mm daily solution repeatability in E/N/U directions, respectively. An average of 13.9 min convergence time and 3.42/2.16/6.65 cm E/N/U positioning accuracy are achieved in the simulated kinematic mode. During a 28-min stepper motor driven movement test, 3.48/14.88 cm 2D/3D kinematic positioning accuracy is obtained using the BDS-3 PPP service.

Determination of horizontal deformation of the Earth`s crust on the territory of Ukraine based on GNSS measurements

The purpose of research is to identify horizontal deformation of the Ukraine territory, using only proven and suitable for geodynamic interpretation GNSS stations. The initial data are observations from 30 GNSS stations for 2017 to 2020. Methodology. The methodology includes the analysis of modern Earth's crust deformations of Ukraine. As a result, for the first time the impact of the coordinates time series created by two different methods: Precise Point Positioning (PPP) and the classical differential method, on determining deformation processes was analysed. It was established that nowadays for the tasks of monitoring, including geodynamic, it is necessary to use the Precise Point Positioning (PPP) method, because the accuracy of determined velocities of the GNSS stations by this method was higher than in the classical differential method. Results. A map of horizontal Earth's crust deformations on the territory of Ukraine was created according to the coordinates time series of GNSS stations. The extension areas of Shepetivka-Starokostiantyniv Khmelnytsky region, Boryspil- Pryluky-Pereyaslav-Khmelnitsky Kyiv and Chernihiv region, as well as a compression area of the Earth's crust in Nizhyn - Stepovi Khutory - Kozelets of Chernihiv region was identified. Additionally, a map of horizontal displacements of the GNSS-stations was created, where the diverse of these displacements was observed, which is likely to be caused by the presence of modern subvertical and sub-horizontal faults and fault areas. For better interpretation of the obtained results, it is necessary to involve geological and geophysical data of tectonic activity of the Ukraine territory.