Global Navigation Satellite System Methods Research Articles

Comparison of the vertical accuracy of satellite-based correction service and the PPK GNSS method for obtaining sensor positions on a multibeam bathymetric survey

The MarineStar Global Navigation Satellite System (GNSS) augmentation services are widely used in bathymetric surveys to obtain the sensor position. The postprocessed kinematic (PPK) GNSS method can be used to obtain more accurate positions. Therefore, the present work aims to verify the vertical final accuracies and uncertainties of exclusive order multibeam hydrographic surveys using the Global Navigation Satellite System (GNSS) as a horizontal positioning tool through methods such MarineStar services and PPK relative positioning, with comparisons between the two methods based on the results of the hydrographic base created. We produced two surfaces with each method, representing the minimum and maximum depths of the bathymetry point cloud. A statistical analysis of the differences between the depth surfaces obtained with the two methods was carried out. When comparing the two surfaces using the PPK method, the difference was less than 10 cm at 95.1% of the points. When comparing the two surfaces to those of the MarineStar, the difference between the maximum and minimum depths was less than 10 cm at 93.1% of the points. The results suggest that using the same survey data, the products obtained with the PPK method would comply with the hydrographic standards, while the MarineStar products would not.

An Interferometric Synthetic Aperture Radar Tropospheric Delay Correction Method Based on a Global Navigation Satellite System and a Backpropagation Neural Network: More Suitable for Areas with Obvious Terrain Changes.

Atmospheric delay correction remains a major challenge for interferometric synthetic aperture radar (InSAR) technology. In this paper, we first reviewed several commonly used methods for tropospheric delay correction in InSAR. Subsequently, considering the large volume and high temporal resolution of global navigation satellite system (GNSS) station measurement data, we proposed a method for spatial prediction of the InSAR tropospheric delay phase based on the backpropagation (BP) neural network and GNSS zenith total delay (ZTD). Using 42 Sentinel-1 interferograms over the Los Angeles area in 2021 as an example, we validated the accuracy of the BP + GNSS method in spatially predicting ZTD and compared the correction effects of BP + GNSS and five other methods on interferograms using the standard deviation (StaD) and structural similarity (SSIM). The results demonstrated that the BP + GNSS method reduced the root-mean-square error (RMSE) in spatial prediction by approximately 95.50% compared to the conventional interpolation method. After correction using the BP + GNSS method, StaD decreased in 92.86% of interferograms, with an average decrease of 52.03%, indicating significantly better correction effects than other methods. The SSIM of the BP + GNSS method was lower in mountainous and high-altitude areas with obvious terrain changes in the east and north, exhibiting excellent and stable correction performance in different seasons, particularly outperforming the GACOS method in autumn and winter. The BP + GNSS method can be employed to generate InSAR tropospheric delay maps with high temporal and spatial resolution, effectively addressing the challenge of removing InSAR tropospheric delay signals in areas with significant terrain variations.

Tracking the water storage and runoff variations in the Paraná basin via GNSS measurements

The Paraná basin is the second largest river basin in South America and provides abundant water resources globally. However, current research lacks hydrological investigation of the region. The vertical crustal deformation recorded by the Global Navigation Satellite System (GNSS) can be used to accurately estimate regional-scale terrestrial water storage (TWS). Therefore, we utilized the daily vertical displacement time series data at 102 GNSS stations to recover the water storage variations in the Paraná basin from 2013 to 2020. To recognize primary spatiotemporal features of TWS changes, we applied the principal component analysis (PCA) method in the inversion strategy. Results indicate that the TWS variations inferred from GNSS generally align in spatiotemporal patterns with estimates from both the Gravity Recovery and Climate Experiment (GRACE) and the Global Land Data Assimilation System (GLDAS). However, some discrepancies are evident at local scales. The TWS changes derived from both GNSS and GRACE exhibited generally larger magnitude of oscillations than those estimated by GLDAS, while the GRACE results neglected the evident seasonal oscillation of the water mass in the southeast of the basin. Given the challenge of capturing large-scale runoff variations through in-situ observations, we innovatively applied GNSS and water budget closure method to provide a novel runoff estimate for the Paraná basin. The GNSS-inferred runoff exhibited a strong correlation (correlation coefficient of 0.72) with in-situ observations. Overall, our study fills the critical knowledge gap in geodesy-based hydrological investigation in the Paraná basin. We aim to highlight the immense potential of GNSS for hydrological parameter estimation and provide valuable reference data for regional hydrological research and for water resources management.

Can GNSS Derived Height Replace Levelling Height? - A Case of Low-Land of Nepal

Orthometric height is the generally adopted type of height worldwide and in geomatics community. Precise levelling has been the method of obtaining orthometric height in past for most of the country, so as the Nepal. However, due to wide usage of Global Navigation Satellite System (GNSS), the alternative approach of combining GNSS derived ellipsoidal height with geoid undulation to get GNSS derived orthometric height, has been used extensively. In Nepal, this technique was officially adopted in 2020 for Everest height measurement and understood as the efficient way to comply with levelling height. In this study, GNSS surveying was conducted on 15 stations located at the lowland region of Nepal and orthometric heights were obtained from GNSS and geoid method. When compared GNSS derived orthometric height with precise levelling height, the difference remained within threshold of 5cm for majority of observation stations. However, these differences are not sufficient to support the standards set for the third order levelling by Survey Department (SD). The accuracy of GNSS derived orthometric height can be significantly affected by various environment and existing resources such as existing accuracy of geoid, nature of precise levelling height. Considering the revisit upon these conditions, we expect GNSS-levelling as a strong alternative to time consuming, tedious, and costly precise levelling which is most suitable method of obtaining orthometric height in lowland topography at a precision less than 4 cm.

A Hybrid RISS/GNSS Method During GNSS Outage in the Land Vehicle Navigation System

The integrated navigation system of an inertial navigation system (INS) and a global navigation satellite system (GNSS) is a standard solution in land vehicle navigation applications. Considering a low-cost solution, the reduced inertial sensor system (RISS) is adopted in place of INS to provide better navigation performance for land vehicles with fewer inertial sensors and lower computations. However, low-cost sensors can quickly deteriorate the navigation solution during GNSS outage. Hence, a novel RISS /GNSS method with the assistance of the long short-term memory (LSTM) neural network (NN), which has the ability of adaptive memorizing, is proposed to bridge GNSS outage by means of data fusion. In addition, zero-velocity detection is applied to advance the navigation performance provided by the LSTM algorithm during GNSS outage. We examined the performance of this method by using real road test experiments in a land vehicle equipped with GNSS receivers and inertial sensors in addition to a high-end GNSS /INS to provide the reference solution. During 300-s GNSS outage, the experimental results illustrate that this hybrid method based on the LSTM algorithm can enhance the navigation accuracy by 50% when compared with the standalone RISS algorithm, and provide 30% improvements in comparison with the nonlinear autoregressive with exogenous input (NARX) algorithm.

QUALITY ASSESSMENTS OF UNMANNED AERIAL VEHICLE (UAV) AND TERRESTRIAL LASER SCANNING (TLS) METHODS IN ROAD CRACKS MAPPING

Abstract. In general, poor road conditions, specifically road cracks constitute a public nuisance, causing troublesome to road users, severe damage to vehicles and accidents. Hence, it is essential to detect the road crack earlier as an early-stage preventive for maintenance, but traditional inspection method used in Malaysia to physically collect the road information is extremely time-consuming, hazardous and labour-intensive. Nowadays, new technologies have improved the measuring performance. This leaves a gap in comparing two modern technologies in road cracks mapping. This study aims to explore the quality assessment between the unmanned aerial vehicle (UAV) and terrestrial laser scanning (TLS) methods in road cracks mapping. Two study areas inside the campus of Universiti Teknologi Malaysia (UTM), Johor, were selected. The ground control points (GCPs) and check points (CPs) at the study areas were georeferenced by global navigation satellite system (GNSS) data with MyRTKNet and ISKnet connections. Low altitude aerial imageries were collected using DJI Phantom 4 UAV, while Topcon GLS-2000 was employed to acquire the dense data of the cracked road. GNSS and manual inspection methods were performed to evaluate the results. In terms of mapping and measurement, both TLS and UAV methods produce almost similar results with average RMSE differences ranging from ±0.003 m to ±0.030 m and ±0.042 m to ±0.224 m respectively. This revealed that TLS is more accurate than UAV in mapping and measuring work. Differences in DTM quality across these approaches is below two (2) cm. Based on this study, TLS is more reliable than UAV. However, UAV offers advantages based on several considerations such as cost, time, safety, and accessibility. In summary, findings from this study shed some light to the authorities on the feasibility of UAV and TLS methods in road cracks mapping.

GNSS Technology for Precise Positioning in CCAM: A Comparative Evaluation of Services

Cooperative, connected, and automated mobility (CCAM) can lead to a significantly improved transport system by increasing safety and efficiency, and reducing emissions. To achieve the goal of fully automated mobility and self-driving vehicles, accurate and reliable positioning is essential. Positioning methods in CCAM often use sensor fusion combining data from multiple sensors with Global navigation satellite system (GNSS) positioning data. In this paper, we focus on the status of GNSS technology by investigating position accuracies and integrities of different state-of-the-art GNSS technologies. We conduct field tests using a self-driving vehicle in Drammen, Norway. Three different types of GNSS positioning services are explored, and a reference trajectory delivered by the vehicle’s navigation system is used to determine the performance of each service. We show that the performance of the GNSS methods alone does not fulfill the requirements needed to obtain fully automated mobility. Moreover, we observe a general decreasing trend in GNSS accuracy for more challenging surroundings.

Improved GNSS vector tracking loop to enhance the navigation performance of USV

The Global Navigation Satellite System (GNSS) is the most common source of location and heading information for unmanned surface vehicle (USV) in real time. However, in areas such as ports or bridges, the GNSS signal will be occluded or weakened. The carrier frequency and code frequency of scalar tracking (ST) in GNSS receiver fluctuates greatly, and even the tracking loop will lose lock. To enhance the navigation performance of USV's GNSS receiver, this paper proposes a framework that uses fixed-lag smoothing (FLS) to assist vector tracking (VT) and applies unscented Kalman filter in the navigation processor. The pseudo-range error and pseudo-range rate error are used as the measurements of navigation processor. FLS serves as a backward filter to enhance the tracking ability of the code loop. The field experiments show that the positioning error of the proposed method is reduced by 72.1% compared to the traditional VT method in the open-sky environments. When the signal is occluded, the positioning results of the traditional ST are dispersed, and also the traditional VT method displays a large error. Moreover, the proposed method is able to reduce the positioning error by 85.4%. The proposed GNSS loop tracking architecture and method can provide a possible solution for USV's navigation system development.

Analysis of GNSS, Hydroacoustic and Optoelectronic Data Integration Methods Used in Hydrography.

The integration of geospatial data in hydrography, performed using different measurement systems, involves combining several study results to provide a comprehensive analysis. Each of the hydroacoustic and optoelectronic systems is characterised by a different spatial reference system and the method for technical implementation of the measurement. Therefore, the integration of hydrographic data requires that problems in selected fields of electronics, geodesy and physics (acoustics and optics) be solved. The aim of this review is to present selected fusion methods applying the data derived from Global Navigation Satellite System (GNSS), Real Time Kinematic (RTK) measurements, hydrographic surveys, a photogrammetric pass using unmanned vehicles and Terrestrial Laser Scanning (TLS) and compare their accuracy. An additional goal is the evalution of data integration methods according to the International Hydrographic Organization (IHO) S-44 standard. The publication is supplemented by implementation examples of the integration of geospatial data in the Geographic Information System (GIS). The methods described indicate the lack of a uniform methodology for data fusion due to differences in both the spatial reference systems and the techniques used. However, the integration of hydroacoustic and optoelectronic data allows for high accuracy geospatial data to be obtained. This is confirmed by the methods cited, in which the accuracy of integrated geospatial data was in the order of several centimetres.

Smartphone-based GNSS Method for Covid-19 Information on Android (Case Study: Surabaya City)

Coronavirus disease 2019 (Covid-19) is the respiration diasease that can be transmitted from individual to another. There have been 3906 ODP (individual on monitoring) cases, 3303 PDP (patient under surveillance) cases, 2918 confirmed cases, 766 recovered patients, and 282 deaths in Surabaya, as recorded on June 6th, 2020. GIS (Geographical information system) is a science based on computer software, to provide digital form information and the earth’s geographic surface analysis. GNSS (global navigation satellite system) is the positioning system method using satellite, which can be used by a lot of people at the same time and designed to obtain three-dimension position. The combination of Smartphone’s GNSS positioning and the spatial data of Covid-19 distribution in Surabaya is expected to be able to give useful information about health condition toward citizen, especially about Covid-19 pandemic via application based. The outcome is a color-level based distribution of Covid-19 cases which can be accessed android smartphone. Sub district with the highest rate of Covid-19 cases does not necessarily have proper health protocol facilities, and so does other sub districts with high rates of Covid-19 cases. In fact, none of Covid-19 referral hospital located in the sub district with high rate of Covid-19 cases. Based on the results of the questionnaire, the applications namely “Cegah Covid-19 Surabaya” has received good responses. This application is currently able to run on Android smartphones with the versions of Android 10, Pie, Oreo, Nougat, Marshmallow, and Lollipop.

Sea Topography of the Ionian and Adriatic Seas Using Repeated GNSS Measurements

The mean sea surface topography of the Ionian and Adriatic Seas has been determined. This was based on six-months of Global Navigation Satellite System (GNSS) measurements which were performed on the Ionian Queen (a ship). The measurements were analyzed following a double-path methodology based on differential GNSS (D-GNSS) and precise point positioning (PPP) analysis. Numerical filtering techniques, multi-parametric accuracy analysis and a new technique for removing the meteorological tide factors were also used. Results were compared with the EGM96 geoid model. The calculated differences ranged between 0 and 48 cm. The error of the results was estimated to fall within 3.31 cm. The 3D image of the marine topography in the region shows a nearly constant slope of 4 cm/km in the N–S direction. Thus, the effectiveness of the approach “repeated GNSS measurements on the same route of a ship” developed in the context of “GNSS methods on floating means” has been demonstrated. The application of this approach using systematic multi-track recordings on conventional liner ships is very promising, as it may open possibilities for widespread use of the methodology across the world.

An Improved GNSS and InSAR Fusion Method for Monitoring the 3D Deformation of a Mining Area

Accurate measurement of the surface three-dimensional deformation fields in a mined-out area is essential for understanding the law of mining subsidence and guiding the safe production and construction of mining areas. In this study, we proposed an improved fusion method to monitor this three-dimensional deformation. We used the Helmert variance component estimation (HVCE) method and the back-propagation neural network (BPNN) to fuse the global navigation satellite system (GNSS) and interferometric synthetic aperture radar (InSAR) measurements. Based on this improved fusion method, we measured the three-dimensional deformation in the West Second Mining Area of Jinchuan, Jinchang City, Gansu Province, China, from March 22, 2019, to June 8, 2020. The root mean square errors (RMSEs) based on our method for the three directions of east-west (E-W), north-south (N-S), and up-down (U-D) were 21.4 mm, 7.6 mm, and 34.2 mm, respectively. These RMSE values are lower than those obtained from previous methods. The results show that the spatial distribution of the three-dimensional deformation follows the law of mining subsidence.

DIGITAL SURFACE MODEL DERIVED FROM UAS IMAGERY ASSESSMENT USING HIGH-PRECISION AERIAL LIDAR AS REFERENCE SURFACE

Abstract. Imagery captured from aerial unmanned systems (UAS) has found significant utility in the field of surveying and mapping as the efforts of the computer vision field combined the principles of photogrammetry. Its respectability in the remote sensing community as increased as the miniaturization of on-board survey-grade global navigation satellite system (GNSS) signal receivers has made it possible to produce high network accuracy contributing to effective aerotriangulation. UAS photogrammetry has gained much popularity because of its effectiveness, efficiency, economy, and especially its availability and ease of use. Although photogrammetry has proven to meet and exceed planimetric precision and accuracy, variables tend to cause deficiencies in the achievement of accuracy in the vertical plane. This research aims to demonstrate achievable overall accuracy of surface modelling through minimization of systematic errors at a significant level using a fixed-wing platform designed for high-accuracy surveying with the eBee Plus and X models by SenseFly equipped with survey-grade GNSS signal-receiving capabilities and 20MP integrated, fixed-focal length camera. The UAS campaign was flown over a site 320 m by 320 m with 81 surveyed 3D ground control points, where horizontal positions were surveyed to 1.0 cm horizontal accuracy and 0.5 cm vertical accuracy using static GNSS methods and digital leveling respectively. All AT accuracy was based on 75 independent checkpoints. The digital surface model (DSM) was compared to a reference DSM generated from high-precision manned aerial LiDAR using the Optech Galaxy scanner. Overall accuracy was in the sub-decimeter level vertically in both commercial software used, including Pix4Dmapper and Agisoft Metashape.

Research on Combined Location Method of Dual Rail Inspection Vehicle Based on Adaptive Kalman Filter

Dual rail inspection vehicle has the function of inspecting rail defect points automatically and an odometer is required for its localization. Since real-time localization of rail defect points still needs manual calibration, it cannot meet the requirements of automatic vehicle operation. In this paper, the automatic localization methods are discussed. The Adaptive Kalman Filter (AKF) is employed for the multi-sensor data fusion of the odometer and the Global Navigation Satellite System (GNSS). Then the GNSS/odometer combined localization model has been built to improve the accuracy and reliability of the inspection vehicle localization. In addition, the hardware board is designed. Finally, the on-line test has been performed on the Shanghai-Hangzhou railway line. The experimental results show that our combined localization method can significantly improve the accuracy compared with that of the single GNSS method from 1.848m to 1.093m.

Bathymetric Monitoring of Alluvial River Bottom Changes for Purposes of Stability of Water Power Plant Structure with a New Methodology for River Bottom Hazard Mapping (Wloclawek, Poland).

The aim of this research was to produce a new methodology for a special river bottom hazard mapping for the stability purposes of the biggest Polish water power plant: Włocławek. During the operation period of the water power plant, an engineering-geological issue in the form of pothole formation on the Wisła River bed in the gravel-sand alluvium was observed. This was caused by increased fluvial erosion resulting from a reduced water level behind the power plant, along with frequent changes in the water flow rates and water levels caused by the varying technological and economic operation needs of the power plant. Data for the research were obtained by way of a 4-year geodetic/bathymetric monitoring of the river bed implemented using integrated GNSS (Global Navigation Satellite System), RTS (Robotized Total Station) and SBES (Single Beam Echo Sounder) methods. The result is a customized river bottom hazard map which takes into account a high, medium, and low risk levels of the potholes for the water power plant structure. This map was used to redevelop the river bed by filling. The findings show that high hazard is related to 5% of potholes (capacity of 4308 m3), medium with 38% of potholes (capacity of 36,455 m3), and low hazard with 57% of potholes (capacity of 54,396 m3). Since the construction of the dam, changes due to erosion identified by the monitoring have concerned approximately 405,252 m3 of the bottom, which corresponds to 130 Olympic-size pools. This implies enormous changes, while a possible solution could be the construction of additional cascades on the Wisła River.

Using the GNSS method assisted with UAV photogrammetry to monitor and determine deformations of a dump site of three open-pit marble mines in Eliktekke region, Amasya province, Turkey

The determination and monitoring of deformations that may occur in the benches of dump sites of open-pit mines are important for both security and continuity of mine production. The Global Navigation Satellite System (GNSS) is the most preferred method for deformation monitoring at dump sites. While the amount of deformation (3D displacements) can be determined at the points monitored by the GNSS method, interpretations on the cause and/or areal size of the deformation may remain limited. The main factors or triggering causes of slope failures at dump sites are base topography, geometric dimensions (width, height, and slope) of the formed benches, stiffness ratio of the dumped material, and load increases caused by new dumps in the lower benches. In this study, UAV photogrammetry and GNSS were used together, and the deformations at the adjacent dump site of three different open-pit marble mines located in Eliktekke region of Amasya province in Turkey were monitored. The GNSS method determined the points where displacements occurred, and the UAV photogrammetry searched for the causes of mobility at the point and its areal and volumetric sizes. The UAV photogrammetric results revealed that the topographic slope and overall slope inclination triggered the movement of the zones. Field measurements and evaluations made for this dump site showed that the current geometry should be kept where the overall slope inclination reaches 14° and not to be increased further. The results support that the GNSS method assisted with UAV photogrammetry is a rapid and economical method to determine both the borders and volumetric sizes deformations as their causing parameters. Through the proposed methodology, it will be possible to effectively determine the main factors causing slope failures in similar areas and to take the necessary measures on time.

Integration of the GNSS method and borehole camera to model the resulting spherical cavity generated by the main charge blast in clay

A depth camera was used to record the spherical cavity which occurred during blasting in clay soil. For this purpose, the integration of the Global Navigation Satellite System (GNSS) method was applied in addition to the depth camera and the laser, to determine the resulting spherical cavity. The expanded spherical cavity, formed after the blasting of the explosive charge in the bottom of the borehole, was measured by a depth camera-laser system. The GNSS measurement method was instrumental for obtaining the coordinates of the borehole. The Multichannel Analysis of Surface Waves (MASW) measurement method was also used during the study. Shear wave velocities (V S ) were calculated using MASW method to evaluate the dynamic properties of the clay soil along the in-situ profiles. The results obtained in this way, showed that there was an increase in the stiffness of the surrounding clay soil after blasting. The main objective of the study was to determine the resulting shapes and volume of the occurred cavities. For a more detailed graphical interpretation, an application was developed, which calculates the coordinates, shape and volumes of the formed spherical cavity.

A Method for Determination and Compensation of a Cant Influence in a Track Centerline Identification Using GNSS Methods and Inertial Measurement

At present, the problem of rail routes reconstruction in a global reference system is increasingly important. This issue is called Absolute Track Geometry, and its essence is the determination of the axis of railway tracks in the form of Cartesian coordinates of a global or local coordinate system. To obtain such a representation of the track centerline, the measurement methods are developed in many countries mostly by the using global navigation satellite system (GNSS) techniques. The accuracy of this type of measurement in favorable conditions reaches one centimeter. However, some specific conditions cause the additional supporting measurements with a use of such instruments as tachymetry, odometers, or accelerometers to be needed. One of the common issues of track axis reconstruction is transforming the measured GNSS antenna coordinates to the target position, i.e., to the place between rails on the level of rail heads. The authors in their previous works described the developed methodology, while this article presents a method of determining the correction of horizontal coordinates for measurements in arc sections of the railway track. The presence of a cant causes the antenna’s center to move away from the track axis, and for this reason, the results must be corrected. This article presents a method of calculation of mentioned corrections for positions obtained from mobile satellite surveying with additional inertial measurement. The algorithm presented in the article and its implementation have been illustrated on an example of a complex geometric layout, where cant transitions exist without transition curves in horizontal plane. Such a layout is not preferable due to the additional accelerations and their changes. However, it allows the verification of the presented methods.

АНАЛІЗ ПЕРСПЕКТИВНИХ СИСТЕМ ЗОНАЛЬНОЇ НАВІГАЦІЇ

Стаття присвячена питанню позиціонування літального апарату, а саме резервним чи альтернативним до супутникових методам визначення координат місцеположення у просторі. Виконано детальний аналіз сучасних засобів позиціонування за сигналами наземних кутомірних та далекомірних радіомаяків, щодо відповідності вимогам зональної навігації RNP/RNAV. Розглянуті можливі шляхи підвищення точності позиціонування за парами далекомірних радіомаяків. Крім того, проаналізовано можливості мультилатераційних систем, пасивного використання сигналів далекомірного обладнання, псевдосупутникових та позиціонування засноване на зворотних відстанях, виділено переваги та недоліки кожного з методів. Розроблено загальну класифікацію засобів позиціонування літака з урахуванням перспективних засобів зональної навігації. Висновки. На сьогоднішній день методи позиціонування за парами радіонавігаційних засобів є широко розповсюджені, проте їх точність обмежена геометрією взаємного місцерозташування, що є причиною невідповідності майбутнім вимогам зональної навігації. Відповідно до виконаного аналізу, найбільш перспективними засобами альтернативного позиціонування є застосування мультилате-раційних та псевдосупутникових систем. У той час як пасивне використання DME, MOSAIC чи DivR потребують значних затрат на розбудову наземної мережі та зміну бортового обладнання ПК. Вагомим є застосування цифрових мереж передачі даних, що підтримують функцію позиціонування за наземними станціями.

Application of GNSS Methods for Monitoring Offshore Platform Deformation

Global Navigation Satellite System (GNSS) has become a powerful tool for high-precision deformation monitoring application. Monitoring of deformation and subsidence of offshore platform due to factors such as shallow gas phenomena. GNSS is the technical interoperability and compatibility between various satellite navigation systems such as modernized GPS, Galileo, reconstructed GLONASS to be used by civilian users. It has been known that excessive deformation affects platform structurally, causing loss of production and affects the efficiency of the machinery on board the platform. GNSS have been proven to be one of the most precise positioning methods where by users can get accuracy to the nearest centimeter of a given position from carrier phase measurement processing of GPS signals. This research is aimed at using GNSS technique, which is one of the most standard methods to monitor the deformation of offshore platforms. Therefore, station modeling, which accounts for the spatial correlated errors, and hence speeds up the ambiguity resolution process is employed. It was found that GNSS combines the high accuracy of the results monitoring the offshore platforms deformation with the possibility of survey.