Geodetic System Research Articles

ADJUSTMENT OF A REGIONAL ALTIMETRIC NETWORK, IN BRAZIL, TO ESTIMATE NORMAL HEIGHTS AND GEOPOTENTIAL NUMBERS

In 2018, the Brazilian Institute of Geography and Statistics (IBGE) defined the normal height values and geopotential numbers for the High Precision Altimetric Network (HPAN), creating the need for developing procedures able to adapt works correlated with the Brazilian Geodetic System (BGS). In that context, and considering the state and municipal altimetric networks, it is necessary to estimate normal heights. To this end, this paper proposes to estimate normal height values and geopotential numbers for the Altimetric Network of the Federal District (AN-DF). Computational procedures involving the Least Squares Method were established and applied in a geometric levelling survey, which includes 200 stations distributed throughout the study area. The obtained results allowed estimating the normal heights of the network stations with accuracy up to 0.032m. However, because significant differences were found in the adjusted and known values of some used HPAN stations, we recommend a rigorous analysis of these stations before using them. In any case considering that the geometric levelling and the applied procedures were carried out correctly, it is suggested that the values estimated for all stations of the AN-DF in this work may be used.

Improved specular point prediction precision using gradient descent algorithm

Global Navigation Satellite Systems Reflectometry (GNSS-R) utilizes GNSS signals reflected off the Earth surface for remote sensing applications. Due to weak power of reflected signals, GNSS-R receiver needs to track reflected signals by open loop. The first step is to calculate the position of specular point. The specular point position error of the existing algorithm—Quasi-Spherical Earth (QSE) Approach—is about 3 km which may cause troubles in data post-processing. In this paper, gradient descent algorithm is applied to calculate position of specular point and the calculation is based on World Geodetic System 1984 (WGS 84) ellipsoid in geodetic coordinate. The benefit of this coordinate is that it is easy to investigate the effect of real surface’s altitude. Learning rate—the key parameter of the algorithm—is adaptively adjusted according to initial error, latitude and gradient descent rate. With self-adaptive learning rate strategy, the algorithm converges fast. Through simulation and test on Global Navigation Satellite System Occultation Sounder II (GNOS II), the performances of the algorithm are validated. The specular point position error of the proposed algorithm is about 10 m. The speed of the proposed algorithm is competitive compared with the existing algorithm. The test on GNOS II shows that the proposed algorithm has good real-time performance.

Comparison of satellite remote sensing derived precipitation estimates and observed data in Kenya

This study evaluated the accuracy of four satellite remote sensing (SRS) based products in predicting rainfall (amounts and spatial distribution) over Kenya between 1998 and 2013. The four SRS products used include; two satellite products (Climate Hazards Group InfraRed Precipitation with Station (CHIRPS 2.0) and Tropical Rainfall Measuring Mission - Multi-satellite Precipitation Analysis (TMPA) 3B42 version 7 (TRMM)), one gauge-interpolated product (Global Precipitation Climatology Centre (GPCC)) and one re-analysis product (Modern-Era Retrospective Analysis for Research and Application (MERRA)). The monthly precipitation data were evaluated for completeness, converted to individual raster files, projected to the World Geodetic System (WGS) 1984 - Universal Transverse Mercator (UTM) zone 37 N ensuring a similar processing extent, rescaled to a common resolution and reclassified following defined uniform intervals for ease of comparison. Thereafter, they were subjected to five different metrics based on eight agro-ecological zones (AEZs) of Kenya, in reference to observed rainfall data obtained from Kenya meteorological department (KMD). Results show that all SRS products both overestimated or underestimated rainfall amounts on a pixel to pixel comparison. Based on point to point proportion of variance evaluation (r2), TRMM best-estimated rainfall in the tropical cool humid (r2 = 0.64), tropical warm humid (r2 = 0.58) and tropical cool subhumid (r2 = 0.39) zones and can be used for agricultural advisory services. The GPCC product best-estimated rainfall in the tropical warm semiarid (r2 = 0.46) and warm tropical sub-humid (r2 = 0.21), while CHIRPS 2.0 best-estimated rainfall in the tropical warm arid (r2 = 0.33) and therefore the two products could be best used to predict rainfall in the ASALs and drought-related studies, with potential for irrigation. The MERRA product best-estimated rainfall in tropical cool arid (r2 = 0.97) and tropical cool semiarid (r2 = 0.53) and could, therefore, be best used for high elevation and drought-related studies. These results demonstrate the promising potential of the satellite remote sensed data in complementing the existing meteorological observed data which are often marred by inconsistency and scarcity, and hence unreliable in the existing agricultural advisory and other climate-based applications in Kenya, and sub-Saharan Africa at large. However, given the observed AEZ dependant variations in the satellite estimates, it is advisable to choose the most suitable SRS product for specific activities per AEZ and calibrate before utilisation.

EVALUATION OF MONITORING THE PROCESS OF DEFORMATION AND SEDIMATION OF A RIGHT LINE VERTICAL ROD

Elements of building structures (EBS) undergo various kinds of deformation as a result of force and temperature effects. As long as the deformations are within the design values, they are not terrible for the structures of the structure, however, if they exceed the permissible values, then there may be a danger of their operation. Therefore, many large, complex, critical structures are constantly monitored by engineering geodesy methods and using sensors of deformations, displacements, tilts, etc.On the example of a vertical rod made of low-carbon steel, which is rigidly fixed and deformed as a result of subsidence of the lower base, the calculation of the accuracy of measuring the tensile strain is calculated, provided that it allows you to track the elastic limits. The calculation shows that the accuracy of measuring the tensile deformation of low-carbon steel is very high and can increase even more for metals of increased strength and with a different (less pronounced) tensile diagram. But modern devices can measure deformations with such precision. Such devices in the form of strain gauge networks are included in the general geodetic monitoring system.

Review of types of geodesic monitoring of deformations of buildings and structures under difficult engineering-geological conditions

The introductory article is a review, the article examines and analyzes the latest research and publications on this issue, namely, engineering and geodetic monitoring of deformations of buildings and structures in the modern development of the construction industry. The introductory article discusses the main types of deformed state of engineering structures, considers the problem of monitoring ground masses. The basic methods of geodetic monitoring of deformations of building structures in complex engineering geological conditions are presented. An extensive list of applications and the relevance of the development of geodetic monitoring of deformations is given. Common methods and instruments for geodetic deformation monitoring are considered: leveling, linear-angular measurements, automated geodetic systems - they are used for remote data acquisition and on-line, the implementation of laser scanning (terrestrial, air and automobile) and the process of complex shooting, using satellite navigation systems, stereophotogrammetry, the use of inclinometers in combination with geodetic instruments for monitoring engineering structures and soil masses. The advantages and disadvantages of modern geodetic monitoring methods are given.

On the transformation of the coordinates of points from the SK-42 system to WGS-84

The significant and effective use of global positioning satellite systems for solution of important theoretical and applied problems of Earth sciences means the preserving of the possibility to use a huge quantity of geodetic, cartographic, gravimetric and other data created on the basis of traditional methods and in different referencing coordinate systems. It is impossible without the correct coordinate transformation at the transition from one system to another. The determination of the coordinates of points using the satellite radio navigation system NAVSTAR GPS is closely related to the world geodetic coordinate system WGS-84. At the same time, data on gravity observations within the Pulkovo 1942 coordinate system have been accumulated in large volumes. It is obvious the need for recalculation of coordinates given in different systems. Information is given on the coordinate systems, geodetic coordinates, units of measurement, display formats for latitude and longitude values. The reference coordinate system of Pulkovo 1942 and the modern world geodetic system WGS-84 are described in sufficient detail. Formulas are given for calculating the normal gravity in these systems. Historical background and classification of coordinate transformation methods are considered. Significant role is given to the high-precision method of Molodensky and the modified Helmert method of coordinate transformation. The standard method of Molodensky is described at the level it is described in official open reports of US government agencies. Programs are considered that automate the solution of the problem of recalculating the coordinates of objects, as well as the issues of transformation of coordinate systems in geographical information systems. The attention is focused on the rash use of the software that might lead to some very strange and inexplicable results.

Future TRFs and GGOS – where to put the next SLR station?

Abstract. Satellite Laser Ranging (SLR) is one of the four geodetic space techniques contributing to the realisation of terrestrial reference frames (TRFs) as well as to the determination of Earth Rotation Parameters (ERPs). The current SLR tracking network suffers from an insufficient network geometry due to a lack of stations especially in the southern hemisphere. Previous simulation studies have shown that the extension of the global SLR tracking network is indispensable for reaching the target accuracy of future TRFs according to user requests and the ambitious goals of the Global Geodetic Observing System (GGOS). The simulation study presented here puts the focus on a determination of the locations where additional SLR stations are most valuable for an improved estimation of the geodetic parameters. Within the present study, we perform a simulation of a set of stations distributed homogeneously over the globe and compare different solutions, always adding one of these simulated stations to the real SLR station network. This approach has been chosen in order to be able to investigate the deficiencies of the existing SLR network and to judge in which regions on the globe an additional SLR station would be most valuable for the improvement of certain geodetic parameters of SLR-derived reference frames. It is shown that the optimum location of a future SLR station depends on the parameter of interest. In case of the ERPs, the main potential for improvement by a single additional station can be shown for locations in polar regions (improvement for ypole up to 7 %) and for locations along the equator for the lengh of day (LOD, improvement up to 1.5 %). The TRF parameters would benefit from an additional station around the pierce points of the axes of the terrestrial reference frame (improvement for ty up to 4 %), the Arctic and the Pacific Ocean region (tz improved by up to 4.5 %), and the Antarctic and the Indian Ocean region (scale improved by up to 2.2 %). As outcome of this study, it is concluded that an additional SLR site in the Antarctic region might be of first priority, enabling improvements in the pole coordinates and the scale of the TRF; potential further sites are recommended in the equatorial region, especially beneficial for the origin of the realised TRF as well as for LOD.

A Föld alakja és a geodinamika

Az 1960-as évek végén az ELTE Geofizikai Tanszékén megalakult Űrkutató Csoport és a Budapesti Műszaki Egyetem bázisán, nagyrészt diákköri munka keretében kezdődtek meg a hazai Doppler-geodéziai mérések, melyek célja földfelszíni pontoknak a Föld tömegközéppontjához rögzített koordináta-rendszerben történő helymeghatározása volt, műholdas jelek vételével. A jelen munkában összefoglalt kutatás eredményeként a mérési pontok helymeghatározásának pontossága ugyanabba a nagyságrendbe esett és alig maradt el a NASA által ugyanebben az évtizedben az amerikai űrprogram földi követőállomásainak hasonló módszerrel elvégzett helymeghatározásához képest. Ez a munka jelentette Horváth Ferenc kutatói pályafutásának kezdetét. Cikkünk végén bemutatjuk, hogy az űrgeodézia már ebben az időszakban is kapcsolódott a Föld dinamikai szerkezetének megértéséhez.

GLONASS-Aided High-Precision Navigation of Space Geodetic Systems

The paper considers the methods of high-precision navigation of space geodetic systems. A technology of determining the orbit parameters by kinematic and dynamic methods using GLONASS signals is proposed. It is for the first time that experimental estimates of position errors have been obtained in a study case of Geo-IK-2 spacecraft, with the measurement residuals of the global quantum-optical network being at the level of 0.06 m (RMS).

Gravitational deformation of ring-focus antennas for VGOS: first investigations at the Onsala twin telescopes project

The receiving properties of radio telescopes used in geodetic and astrometric very long baseline interferometry (VLBI) depend on the surface quality and stability of the main reflector. Deformations of the main reflector as well as changes in the sub-reflector position affect the geometrical ray path length significantly. The deformation pattern and its impact on the VLBI results of conventional radio telescopes have been studied by several research groups using holography, laser tracker, close-range photogrammetry and laser scanner methods. Signal path variations (SPV) of up to 1 cm were reported, which cause, when unaccounted for, systematic biases of the estimated vertical positions of the radio telescopes in the geodetic VLBI analysis and potentially even affect the estimated scale of derived global geodetic reference frames. As a result of the realization of the VLBI 2010 agenda, the geodetic VLBI network is currently extended by several new radio telescopes, which are of a more compact and stiffer design and are able to move faster than conventional radio telescopes. These new telescopes will form the backbone of the next generation geodetic VLBI system, often referred to as VGOS (VLBI Global Observing System). In this investigation, for the first time the deformation pattern of this new generation of radio telescopes for VGOS is studied. ONSA13NE, one of the Onsala twin telescopes at the Onsala Space Observatory, was observed in several elevation angles using close-range photogrammetry. In general, these methods require a crane for preparing the reflector as well as for the data collection. To reduce the observation time and the technical effort during the measurement process, an unmanned aircraft system (UAS) was used for the first time. Using this system, the measurement campaign per elevation angle took less than 30 min. The collected data were used to model the geometrical ray path and its variations. Depending on the distance from the optical axis, the ray path length varies in a range of about pm ,1,hbox {mm}. To combine the ray path variations, an illumination function was introduced as weighting function. The resulting total SPV is about - ,0.5 mm. A simple elevation-dependent SPV model is presented that can easily be used and implemented in VLBI data analysis software packages to correct for gravitational deformation in VGOS radio telescopes. The uncertainty is almost 200,upmu hbox {m} (2sigma ) and is derived by Monte Carlo simulations applied to the entire analysis process.

Satellittgeodesiens tidlige historiei Norge

We describe the first initiative in space geodesy in Norway in 1958, immediately following the dawn of the space age. It opened new research directions in astronomy at the University of Oslo. A satellite tracking station, funded by the US Air Force, was operated as part of a global network of stations. This contract provided state-of-the art equipment and job opportunities for young scientists, but the rapid increase in the number of satellites filled the observing time available and did not allow the instrument to be used for individual research. Oslo Space Track Station became a service unit in the USAF Space Track program, but delivered data that contributed to development of global gravitational models of the Earth and world geodetic reference systems.

Agricultural drainage tile surveying using an unmanned aircraft vehicle paired with Real-Time Kinematic positioning—A case study

A 2012 agricultural census reported approximately 218,000 U.S. farms to have subsurface tile networks that artificially drain over 19.7 million hectares. These drainage networks present a significant expense to landowners during their installation, inspection, maintenance, and upgrading. The conventional methods for locating buried drain tiles are by excavation employing heavy machinery and hand tile probes which are expensive and time-consuming.Aerial photography offers promise as a less-expensive alternative for mapping tile networks over vast acreages. In aerial photography, ground-surface discolorations from the concentratio of draining moisture periodically appear directly atop functioning drains. We have noted drainage surface patterns occurring on Midwestern fields with minimal surface residue one to three days following significant rainfall. An unmanned aerial vehicle (UAV) equipped with visible or thermal infrared (TIR) imaging can detect these distortions at appropriate times. Our study compared Real Time Kinematic (RTK) and Wide Area Augmentation System (WAAS) Global Positioning System (GPS) for mapping of subsurface drain tiles.The case study revealed WAAS GPS provided insufficient accuracy and precision for physically locating the buried tiles. Although more expensive and complicated, satellite RTK technology increases the vertical and horizontal alignment of UAV surveys as it projects aerial imagery precisely and accurately onto a geodetic coordinate system. The pairing of RTK technology with the UAV survey was deemed essential for physically locating buried tile lines in the field.

Validating the vertical quality of SRTM digital elevation model of the Mirim Lagoon hydrographic basin

Abstract. This work is part of a research project that aims at the automatic determination of knickpoints and the assessment of morphometric and hypsometric parameters of Mirim Lagoon Hydrographic Basin, using Shuttle Radar Topography Mission digital elevation model (SRTM-DEM) and spatial analyses.The analysis of geomorphologic systems is done using computational treatment of data obtained by remote sensing, especially those obtained by SRTM. These data permit the elaboration of a topographic model for the Earth surface and provide a base for studies in several units of geomorphologic analyses (geomorphologic systems), such as hydrographic basins.The most usual technique for derivation of relief morphologic attributes is based on digital elevation models (DEMs) and digital hydrographic nets. Computational routines are applied on those data for acquisition of the hydrography and drainage anomalies. The DEMs and the hydrographic nets must have either morphologic or hydrologic consistency to validate the results obtained in the morphometric analyses.More specifically, this study aims at describing the method and related results regarding the validation of the vertical accuracy of SRTM-DEM through a kinematic positioning based on the Global Navigation Satellite System (GNSS), in the Mirim Lagoon Hydrographic Basin region. Mirim Lagoon Hydrographic Basin is as cross-border basin located on the Atlantic coast of South America, and covers an area of 58,407.78 km2, where 47% of this area is in Brazil and 53% in Uruguay.Several studies deal with the validation of Digital Elevation Models (DEMs) and SRTM data using different GNSS surveying methods and receivers. The innovation of this work is the methodology developed to achieve the suitable accuracy for the control points coordinates to validate the SRTM-DEM of Mirim Lagoon Hydrographic Basin. The study used the kinematic relative positioning method with a recording rate of 1 second and without reference stations for post-processing with the precise point positioning (PPP) method. This methodology allowed covering a large area with reference stations being very far from the surveyed region and with different geodetic reference systems (two countries).The methodology entails the GNSS data acquisition and post-processing, the transformation from geometric heights into orthometric heights, the SRTM-DEM mosaic, the extraction of homologous points in the SRTM-DEM and the statistical analyses for validating the model.The study used a GNSS receiver of dual-frequency with recording rate of 1 second to collect a total of 275,916 points with 3D coordinates. Those points were post-processed using the PPP method with the Canadian Spatial Reference System – Precise Point Positioning (CSRS-PPP), and the ellipsoidal height was converted into orthometric height through the software INTPT geoid. During this work, we used the geopotential model (EGM96) to transform height differences between two countries, Brazil and Uruguay.In order to obtain the SRTM-DEM we used 15 SRTM images, version 3, band C, with a spatial resolution of 1 arcsecond (approximately 30 m). These images were individually processed to obtain the Digital Elevation Model Hydrologically Consistent (DEMHC) and to treat the inconsistencies. Afterwards, we created a mosaic with the 15 images.In the statistical analysis we examined the magnitude of absolute errors in the SRTM data. These errors were named discrepancies between the SRTM heights and the heights of GNSS survey points. After the post-processing and the heights conversion, the GNSS survey points were considered accurate and used as a reference for SRTM-DEM validation. The goal of the statistical analysis was to verify if the absolute vertical precision of the DEM data exceeds 16 m, according to the precision specifications of the DEM SRTM.Results showed that the vertical mean absolute error of the SRTM-DEM vary from 0.07 m to ± 9.9 m with average of −0.28 m. This vertical accuracy is better than the absolute vertical accuracy value of ± 16 m published in the SRTM data specification and validates the SRTM-DEM. Besides that, even considering different slopes and different heights the statistics showed that SRTM-DEM could be validated, in spite of the results for lower and flat area were more accurate than the ones for a higher area with high slope.

Closed form algorithm of double-satellite TDOA + AOA localization based on WGS-84 model

In this paper, we consider the double-satellite localization under the earth ellipsoid model of the Wideband Geodetic System (WGS-84) using the Time Difference of Arrival (TDOA) and the Angle-of-Arrival (AOA). Several closed-form solution algorithms via the pseudo-linearization of the measurement equations are presented to efficiently estimate the location. These algorithms include the Weighted Least Squares (WLS), the Constrained Total Least Squares (CTLS), and the Taylor-Series Iteration (TSI). Performance comparison of the proposed methods with the Cramér-Rao Lower Bound (CRLB) in the simulation is shown to demonstrate that the proposed algorithms are feasible and have stable performance.

Proposta dos parâmetros de transformação de coordenadas rectangulares da província de Luanda do elipsoide de Clark 1880 para o WGS 84

A atividade geodésica experimenta uma transformação significativa com o surgimento dos sistemas de posicionamento por observações de Satélites Artificiais Terrestres (SAT). A sua capacidade atual permite a determinação com alta precisão, da posição de qualquer objeto sobre a superfície da terra, aliada à rapidez e comodidade, superando os métodos clássicos em muitos aspetos. Com a adoção do sistema WGS 84 (World Geodetic System), os documentos cartográficos, em uso atualmente e produzidos com base no sistema Clark 1880 que é um sistema topocêntrico, terão de ser transformados ou adequados ao novo referencial geocêntrico. No presente artigo fez-se ênfase na determinação dos parâmetros de transformação na Província de Luanda. Os procedimentos metodológicos seguidos fundamentam-se na pesquisa descritiva, onde se destaca o método dedutivo, com base nos resultados obtidos através dos dados coletados. Neste contexto foram utilizados 8 pontos da Rede Geodésica de Angola (RGA), com coordenadas retangulares, referenciados no elipsoide Clark 1880 e WGS 84. Solucionado o sistema de equações normais, foram estimados os quatro parâmetros de transformação de Luanda (ΔX= -195.9722 metros; ΔY= + 53.8010 metros; γ = 1.5708 arcseg; m = 0.9999), pelo método dos mínimos quadrados. A avaliação dos resultados foi feita pela comparação das diferenças entre as coordenadas estimadas pelo ajustamento e os valores de referência, isto é, os valores conhecidos. Os resultados demonstraram que o modelo se apresenta apropriado para a transformação de bases cartográficas, sobretudo às de escalas iguais ou menores que 1:5000.

Technology of Geodetic Monitoring of Hydropower Structures During Compensation Grouting

A technology for geodetic monitoring of the displacements of hydropower structures during compensation grouting has been developed. Recommendations are provided for optimal composition, configuration, and functional structure of automated geodetic monitoring systems based on robotized tachymeters. The process of handling and analyzing data is shown using the example of the system of monitoring the uplift of structures of the experimental ground of Zagorsk GAES-2. Separate attention is given to visualization of monitoring results.

Multi-Temporal Investigation of the Boulder Clay Glacier and Northern Foothills (Victoria Land, Antarctica) by Integrated Surveying Techniques

The paper aims to detect the main changes that occurred in the area surrounding the Mario Zucchelli Station (MZS) through analysis of multi-temporal remote sensing integrated by geophysical measurements. Specific attention was directed at realizing an integrated geomorphological study of the Boulder Clay Glacier, a partially debris-covered glacier belonging to the Northern Foothills (Victoria Land, Antarctica). This area was recently chosen as the location for the construction of a new semi-permanent gravel runway for MZS logistical airfreight operations. Photogrammetric analysis was performed by comparing three historical aerial photogrammetric surveys (carried out in 1956, 1985, and 1993) and Very High Resolution (VHR) GeoEye-1 satellite stereo-image coverage acquired in 2012. The comparison of geo-referenced orthophoto-mosaics allowed the main changes occurring in some particular areas along the coast nearby MZS to be established. Concerning the study of the Boulder Clay Glacier, it has to be considered that glaciers and moraines are not steady-state systems by definition. Several remote sensing and geophysical investigations were carried out with the main aim of determining the general assessment of this glacier: Ground Penetrating Radar (GPR); Geodetic Global Positioning System (GPS) network; multi-temporal satellite Synthetic Aperture Radar (SAR) interferometry. The analysis of Boulder Clay Glacier moraine pointed out a deformation of less than 74 mm y−1 in a time span of 56 years, value that agrees with velocity and deformation data observed by GPS and InSAR methods. The presence of unexpected brine ponds at the ice/bedrock interface and the deformation pattern observed in the central part of the moraine has to be monitored and studied, especially under the long-term maintenance of the future runway.

USE OF GLOBAL POSITIONING SYSTEM (GPS) FOR BASIC SURVEY ON STUDENTS

As been coming ages, modern technology integrates into every life aspect including in field survey. Nowadays, one of the modern technology namely Global Positioning System (GPS). The GPS system was first developed by the US Department of Defense used for both military and civilian purposes. This system is designed to provide threedimensional position, speed, and information about world which is not affected by time and weather. Presently, GPS has been widely used by people all over the world who is need information about position, speed or time. To determine the coordinates of points on earth, the receiver requires at least 4 satellites to capture the signal correctly with the coordinates obtained referring to the global datum such World Geodetic System 1984 (WGS'84). GPS is divided into 3 types: Type of navigation or handheld, generally used in battle field or navigation purposes. Some vehicles have been equipped with GPS for navigation aids by adding a map to guide the rider thus rider know which pathway should be chosen to arrived at the destination. GPS mapping is a GPS tool used to calculate an area or create an important route in transit. Type Mapping has an accuracy level between 1-3 meters and mapping types require a base station serving to receive satellite signals and transmit them to a GPS receiver. Geodetic type is the most meticulous and most sophisticated type than navigation or mapping because it has a level of accuracy below 1 meter. The price of geodetic type is most expensive.

Application of The KNN Algorithm in Determining the Orientation of The Probability Area Containing The Ship Position by GPS Systems on Hai Phong Coastal Area

The need for navigation for the maritime industry is also very urgent. Today, most commercial boats have receivers and positioning signal receivers, giving an accuracy of several meters. For vessels arriving at, or passing through small canals, the ability to locate with an accuracy of less than 1 meter is necessary. In these cases, the use of DGPS technology is necessary. The determination of ship location and navigation depends on global satellite navigation systems, mainly GPS systems. In maritime practice, the position of the specified vessel is considered the most probable position and will be the center of the circle of probability area containing the ship position. However, the probability area containing the ship position is scalar, the radius of error of the circle of probability area depends on many factors, such as the deviation of geodetic system, the accuracy of the chart. Therefore, the determination of the most probable position with the highest accuracy is a quite complex problem. The demand for data processing is also greater; Machine Learning is thus contributing to solving this problem. In the framework of the article, the authors propose the application of the KNN algorithm to determine the orientation of the probability area containing the ship position with the most probable positions. The objective of this study is to improve efficiency and safety in maneuvering and navigation for sea vessels and testing for Hai Phong coastal area.

ENGINEERING GEODESIC PROVISION OF SPATIAL CONNECTION OF NATURAL OBJECTS

In the article the question of regulation of land relations is considered. It is noted that engineering geodesic investigations provide spatial connection of natural objects and their elements. One of the types of engineering and geodetic works is the removal of in-kind and fixing on the area of coastal strips along the reservoirs, which are carried out in order to create a favorable regime for water objects, preventing their pollution. State geodesic network-geodesic basis topographic units of all scale. Which unites in a single whole planned and high-altitude geodetic networks, created in accordance with the requirements of On approving the procedure for using the state geodetic reference System of coordinates USK-2000 in carrying out work with land management». Bit geodesic networks of thickening are the basis of topographic determinations in scale and engineering works. These works are carried out in the territories of settlements in land planning, land reclamation, land cadaster, use of water resources, etc. Bit geodetic network of thickening creates methods of polygonometry, triangulation and combination of these methods with the use of satellite navigation systems GPS. The method of marking works is chosen depending on the required accuracy of marking the point, the availability of geodetic instruments, the conditions of the area, qualification of the personnel, etc. In this case, the method of direct marking and the method of editing are distinguished. The first method consists in the direct construction of marking sizes with the given accuracy. The second method is based on the preliminary marking of the point, close to the design one, with its subsequent displacement to the design position. The method of direct marking is used, as a rule, in works of less accuracy, and the method of editing - in works that require high accuracy of marking (bridges, dams, etc.) The use of modern devices and technologies (GPS receivers, electronic total stations) allow to carry out geodetic work with greater accuracy and efficiency and convert the geodetic work to the level of new technologies.