Geodetic Coordinates Research Articles

Development of an Autonomous Driving Path-Generation Algorithm for a Crawler-Type Ridge-Forming Robot

The agricultural sector is currently facing problems including a decline in the agricultural population, labor shortages, and an aging population. To solve these problems and increase agricultural productivity, the development and distribution of autonomous agricultural machinery is necessary. Since autonomous agricultural machinery is operated along a pre-defined path, it is essential to generate an autonomous driving path that takes into account the driving and working methods of the agricultural machinery. In this study, an autonomous driving path-generation algorithm for the autonomous operation of a crawler-type ridge-forming robot is proposed. The proposed algorithm defines the field boundary using the geodetic coordinates of the field boundary points and the size of the robot, generates working line segments within the field boundary, and generates three types of waypoints, which constitute an autonomous driving path based on the autonomous driving operating scenario. To verify the proposed algorithm, tests were conducted using four types of field boundary points with different shapes, and the results are presented. As a result of the simulation test, when a ridge was created using the generated autonomous driving path, the area occupied by the ridge in the total field area according to the field types of a rectangle, trapezoid, pentagon, and hexagon was indicated to be 80, 77, 85, and 77%, respectively.

Spatial positioning method based on range-only measurement of multi-station radar

Aiming at the characteristics that affect the high ranging accuracy of shipborne radar, a multi station radar spatial positioning method based on ranging is proposed. This method is based on the ECEF (Earth Centered Earth Fixed) coordinate system, and adopts the method of intersecting the detection distances of multiple radars to the target, and directly calculates the spatial position of the target. This method only needs the geodetic coordinates of each radar station and the detection range of the target to calculate the geodetic coordinates of the target, which can effectively solve the coordinate conversion problem caused by the curvature of the earth, and does not involve higher-order equations and multi-value solutions, and it does not involve iterative initial value calculation. The positioning system can not only obtain high positioning accuracy, but also has a long operating distance, which can better solve the multi-radar range measurement intersection positioning problem.

Precyzyjne wyznaczanie geodezyjne w budowie obiektów inżynierskich z orientacją w określonym kierunku

In the construction practice, there are engineering structures, where some complex requirements in the process of their building have to be meet, e.g., their positioning, geographical orientation and geometric determination. The current publication examines the specificity of geodetic activities, regarding the orientating of the main construction axes of the foundation and the supporting structures of the terrestrial telecommunication antennas in a predetermined direction, for example, in the parallel direction to the geographical meridian. The focus is on the assessment of the accuracy and the choice of appropriate methods and equipment in order to create the required geodetic network, as well as to perform accurate setting out works. The combination of demands, namely for a specific geographic orientation and precise relative accuracy of the setting elements, implies a suitable transition from the ellipsoidal geodetic coordinates to the projection plane of the setting out project. In this connection, the influence of the meridian convergence on the accuracy of the planning setting out works is examined. A mathematical approach is proposed to assess the need of elimination of this factor, depending on the value of the constructional tolerance and the geographic location of the site.The necessary precision for determining the geodetic ellipsoidal coordinates by GNSS (Global Navigation Satellite System) measurements as well as the required accuracy of the planning and elevation setting out works are shown.Using different geodetic methods and tools, a preliminary accuracy assessment approach and the choice of the appropriate coordinate projection and height reference system is also proposed. The real data, which were obtained in different Earth’s locations by the explained methodology, are presented. The established geodetic networks provide orientation of the main construction axes of the bases of the terrestrial communication antennas in the parallel direction to the geodetic meridian with an azimuth standard error - МА = ± 2÷5' (minutеs) and allowable error in distances and eleventions of the setting out elements, respectively - MdS ≤ ±3 mm, Mdh ≤ ± 2 mm.

POSSIBILITIES OF TRANSFORMING RECTANGULAR 3D GEODETIC INTO ELLIPSOIDAL COORDINATES USING NEURONAL NETWORKS

<p class="ABSTRACT">The transition from ellipsoidal geodetic coordinates to rectangular 3D coordinates is quite simple, while the reverse procedure is somehow more complex due to the mathematical relationship between the ellipsoidal width and 3D coordinates. Until now, several methods for solving this problem have been defined and described in geodetic literature. In this paper, the possibility of applying a backpropagation algorithm based on a multilayer perceptron (Multilayer Perceptron – MLP) neural network for the transformation of rectangular 3D geodetic into ellipsoidal coordinates is analyzed. The applied MLP model is based on Bayesian regularization (BR). The adequacy of the model was verified by a robustness test and a cross-validation test. Based on the obtained results, it was concluded that the MLP neural network can be used for the transformation from rectangular 3D to ellipsoidal coordinates. Future research should analyze the possibility of applying this procedure to solve the problem of data transformation.</p>

Accuracy Assessment of UAV LiDAR Compared to Traditional Total Station for Geospatial Data Collection in Land Surveying Contexts

Abstract. Accurate surveying of vegetated areas presents significant challenges due to obstructions that obscure visibility and compromise the precision of measurements. This paper introduces a methodology employing the DJI Zenmuse L2 Light Detection and Ranging (LiDAR) sensor, which is mounted on a Matrice 350 RTK drone. The DJI Zenmuse L2 sensor excels at capturing detailed terrain data under heavy foliage, capable of collecting 1.2 million points per second and offering five returns, thus enhancing the sensor's ability to detect multiple surface responses from a single laser pulse. In a case study conducted near a creek heavily obscured by tree coverage, traditional aerial imaging techniques are found insufficient for capturing critical topographic features, such as the creek banks. Employing LiDAR, the study aims to map these obscured features effectively. The collected data is processed using DJI Terra software, which supports the accurate projection and analysis of the LiDAR data. To validate the accuracy of the data collected from the LiDAR sensor, traditional survey methods are deployed to ground truth the data and provide an accuracy assessment. Ground control points (GCPs) are established using a GNSS receiver to provide geodetic coordinates, which then assist in setting up a total station. This total station measures vertical and horizontal angles, as well as the slope distance from the instrument to positions underneath the tree coverage on the ground. These measurements serve as checkpoints to validate the accuracy of the LiDAR data, thus ensuring the reliability of the survey. This paper discusses the potential of integrating LiDAR data with traditional surveying data, which is expected to enhance the ability of surveyors to map environmental features efficiently and accurately in complex and vegetated terrains. Through detailed procedural descriptions and expected outcomes, the study aims to provide valuable insights into the strategic application of geospatial technologies to overcome common surveying challenges.

Taoism-Net: A Fruit Tree Segmentation Model Based on Minimalism Design for UAV Camera

The development of precision agriculture requires unmanned aerial vehicles (UAVs) to collect diverse data, such as RGB images, 3D point clouds, and hyperspectral images. Recently, convolutional networks have made remarkable progress in downstream visual tasks, while often disregarding the trade-off between accuracy and speed in UAV-based segmentation tasks. The study aims to provide further valuable insights using an efficient model named Taoism-Net. The findings include the following: (1) Prescription maps in agricultural UAVs requires pixel-level precise segmentation, with many focusing solely on accuracy at the expense of real-time processing capabilities, being incapable of satisfying the expectations of practical tasks. (2) Taoism-Net is a refreshingly segmented model, overcoming the challenges of complexity in deep learning, based on minimalist design, which is used to generate prescription maps through pixel level classification mapping of geodetic coordinates (the lychee tree aerial dataset in Guangdong is used for experiments). (3) Compared with mainstream lightweight models or mature segmentation algorithms, Taoism-Net achieves significant improvements, including an improvement of at least 4.8% in mIoU, and manifested a superior performance in the accuracy–latency curve. (4) “The greatest truths are concise” is a saying widely spread by ancient Taoism, indicating that the most fundamental approach is reflected through the utmost minimalism; moreover, Taoism-Net expects to a build bridge between academic research and industrial deployment, for example, UAVs in precision agriculture.

Accuracy of marine gravimetric measurements in terms of geodetic coordinates of land reference benchmark

The article presents how the values of (3D) coordinates of land reference points affect the results of gravimetric measurements made from the ship in sea areas. These measurements are the basis for 3D maritime inertial navigation, improving ships' operational safety. The campaign verifying the network absolute point coordinates used as a reference point for relative marine gravity measurements was described. The obtained values were compared with catalogue values. In verification of network points 3D position the satellite data Global Satellite Navigation System (GNSS) and ground supporting systems (GBAS) was used. In this example, the height difference of the land reference point was 0.32 m. As a consequence, the offset budget of the marine campaign was affected in the range of up to 0.35 mGal. The influence on gravity free-air anomaly was not constant over the entire area covered by the campaign.

Research on Identification and Location of Mining Landslide in Mining Area Based on Improved YOLO Algorithm

The wide range and high intensity of landslides in the mining area pose a great threat to the safety of human life and property. It is particularly important to identify and monitor them. However, due to the serious surface damage, small landslide scale, complex background and other factors in the mining area, it is impossible to accurately identify and detect the landslide in the mining area. It is necessary to select an efficient detection model to detect it. In this paper, aiming at the problem of landslide identification in mining area, the remote sensing image of mining area is obtained by unmanned aerial vehicle (UAV), and the landslide data set of mining area is constructed by data enhancement method. An improved YOLOv8 algorithm is proposed. By adding a mixed attention mechanism in the channel and spatial dimensions, the detection accuracy of the model for mining landslide is improved, and the monitoring of landslide changes in the mining area is successfully completed. At the same time, an algorithm for locating the landslide position is proposed. Through this algorithm, the detected landslide pixel coordinates can be converted into geodetic coordinates. The results show that the improved YOLOv8 algorithm proposed in this paper has a recognition accuracy of 93.10% for mining area landslides. Compared with the mAP@0.5 of the original YOLOv8 algorithm and YOLOv5 algorithm, the improved YOLOv8 algorithm has an increase of 4.2% and 5.1%. This study has realized the monitoring and positioning of the landslide in the mining area, which can provide the necessary data support for the ecological restoration on mining area.

A complete closed-form method for transformation from Cartesian to geodetic coordinates

A complete closed-form method for transformation from Cartesian to geodetic coordinates

Research of measurement accuracy using GNSS RTK method for determining geodetic coordinates of vertical network points

Research of measurement accuracy using GNSS RTK method for determining geodetic coordinates of vertical network points

Determining the coordinates of a ground target from aircraft board using the method of multiple corner notches

The calculating of the stationary ground target coordinates using multiple angular spatial notches obtained using sighting equipment installed on board of a moving aircraft is considered. As intermediate parameters, auxiliary variables were used — slant ranges, which made it possible to reduce the problem to solving a system of linear algebraic equations obtained using the weighted least squares method. A complete algorithm for determining the geodetic coordinates of the target is presented, taking into account the positional and angular position of the aircraft at the time of measurement. Keywords spatial corner notches, multiple notches method, method of the weighted least squares

INDOOR POSITIONING AND NAVIGATION BASED ON QR CODE MAP

Abstract. Solving the indoor positioning problem can effectively improve work and life efficiency. Outdoors, navigation and positioning mainly rely on satellites to provide global positioning and road network topology to constrain the direction of travel. Therefore, to achieve good indoor navigation and positioning, two things are needed: 1) continuous position acquisition and 2) an indoor road network. Since the indoor environment is relatively stable, the geodetic coordinates of key indoor nodes can be obtained in advance through measurement methods and control points can be set up. Inertial navigation is stable and autonomous, and when combined with control points, it can achieve stable position acquisition. QR codes are rich in information, low in cost, and easy to deploy. They can be used as nodes to construct an indoor road network or as control points. This study proposes an indoor road network map construction method that can achieve local accuracy and global consistency in large indoor scenes. In this indoor road network map, node information includes the position and posture of the QR code. When a machine passes through a node position, it can obtain its absolute position and direction in the geodetic coordinate system by taking a picture of the node’s QR code and combining it with IMU fusion positioning. Through map edge information, indoor navigation and path planning can be achieved.

Centimeter-level-precision seafloor geodetic positioning model with self-structured empirical sound speed profile

In-field Sound Speed Profile (SSP) measurement is still indispensable for achieving centimeter-level-precision Global Navigation Satellite System (GNSS)-Acoustic (GNSS-A) positioning in current state of the art. However, in-field SSP measurement on the one hand causes a huge cost and on the other hand prevents GNSS-A from global seafloor geodesy especially for real-time applications. We propose an Empirical Sound Speed Profile (ESSP) model with three unknown temperature parameters jointly estimated with the seafloor geodetic station coordinates, which is called the 1st-level optimization. Furthermore, regarding the sound speed variations of ESSP we propose a so-called 2nd-level optimization to achieve the centimeter-level-precision positioning for monitoring the seafloor tectonic movement. Long-term seafloor geodetic data analysis shows that, the proposed two-level optimization approach can achieve almost the same positioning result with that based on the in-field SSP. The influence of substituting the in-field SSP with ESSP on the horizontal coordinates is less than 3 mm, while that on the vertical coordinate is only 2–3 cm in the standard deviation sense.

On robust estimation of the Gauss–Markov model with a singular covariance matrix

Although the robust parameter estimation has been intensively investigated in statistics and measurement science, no one considers the robust estimation within the Gauss–Markov model (GMM) with a singular covariance matrix. In this contribution, a method of finding the robust solutions in the singular linear model has been suggested based on the generalization of the unified least-squares objective function. The equivalent cofactor matrix in the robust objective function is established by the bifactor strategy based on the IGG III function. The robustness of the proposed robust algorithms is demonstrated with the examples of geodetic coordinates transformation and the free network deformation analysis.

Exact and heuristic formulae to compute the geodetic height from the ellipse equation

The conversion of the cartesian coordinates of a point to its geodetic equivalent coordinates in reference to the geodetic ellipsoid is one of the main challenges in geodesy. The ellipse equation in the meridian plane significantly influences the value of the geodetic coordinates. This research analyzes this influence and how it can contribute to their solutions. The study investigates the mathematical relation between them and presents an exact formula relating to the geodetic height and the ellipse equation. In addition, a heuristic formula for the relation between the geodetic height and the ellipse equation is proposed, which is independent of the geodetic latitude and has a relative accuracy better than 99.9 %. The calculation is stable, and the cost is low.

IMPROVING THE USE OF GEODETIC, GEOCENTRIC, AND TOPOCENTRIC COORDINATE SYSTEMS IN METEOR ASTRONOMY AND RELATED TASKS

The problem of using the geodetic, geocentric, and topocentric coordinate systems in video observations’ processing of meteors and other dynamical objects in Earth’s atmosphere is considered. For meteor heights in a range of 0…200 km and arbitrary Earth’s ellipsoid latitudes, the following values are calculated: the difference between geodetic and geocentric latitudes, the meridian arc length corresponding to this shift, and the difference between geocentric and geodetic altitudes above the Earth’s ellipsoid. The carried-out calculations allowed us to conclude that the geocentric coordinate system is optimal for the calcula- tion of kinematic parameters of meteors and trajectory measurements of ballistic objects at all-range altitudes and long distances between observation points without using horizontal coordinate systems as intermediate ones. This coordinate system is also used in the computation of heliocentric orbit elements of meteoroids. It is noted that the transition from the geocentric to the geodetic coordinate system is necessary for mapping the projections of the meteor trajectory to search for their remnants — meteorites. The reason is related to the difference between them, which can reach 11 arcmin for objects located at an altitude of 100 km above the level of the Earth’s ellipsoid, which corresponds to the shift of 21 km. The difference between geocentric and geodetic altitudes is inessential and amounts to half a meter at an altitude of 100 km and slightly more than one meter at 200 km and can be neglected in meteor calculations and most ballistic tasks. These considerations formed the basis for our proposed alternative vector method for the inverse transition from geocentric to geodetic coordinates and the numerical solution of the corresponding equation. In order to decrease the calculation time for mass processing, it is recommended to change the numerical processing of the inverse task by fitting it with elementary functions. An example of fitting is given. It brings to the maximal deviation in latitude near one arcmin, which corresponds to approximately 35 meters. It is noted that such precision is satisfactory for meteor measurements, but for ballistic problems, the accuracy of fitting must be improved.

THE RESEARCH OF IMPLEMENTATION OF NUMERICAL RIGOROUS MATHEMATICAL METHODS WITH THE PARAMETER OF THE MEMBERS NUMBER IN THE TAYLOR SERIES

The current level of development of geoinformation technologies makes it possible to determine the cartometric properties of terrain objects with a user-defined accuracy. The author of this paper proposes a mathematical model that allows to implement the function of converting geodetic coordinates into rectangular flat Gauss-Kruger projections in a software environment based on the setting of the parameter of the number of members in the Taylor series, adjusting the accuracy of the coordinate transformation and their dimension. The purpose of this work is to implement a mathematical model of a numerical approximate computer method of converting geodetic coordinates into flat rectangular Gauss-Kruger projections. The results of this study will also be used to create functions for converting coordinates from rectangular flat Gauss-Kruger projections to geodetic coordinates and from one 6-degree zone of the Gauss-Kruger projection to another, taking into account the parameter of the number of members in the Taylor series. The proposed mathematical models are recommended to be implemented in the MATLAB or PhyCharm using the necessary libraries. The following studies will focus on determining the areas and lengths of objects located in two or more 6-degree zones of the Gauss-Kruger projection.

AVALIAÇÃO DA ACURÁCIA DA TÉCNICA DE POSICIONAMENTO GNSS PPP-RTK COM O USO DO SERVIÇO DE CORREÇÃO TRIMBLE CENTERPOINT RTX

The use of only one receiver at the user level, together with the solution of phase ambiguities as integer values, are among the main advantages of the PPP-RTK GNSS Positioning Technique. However, it is necessary to have a Geodetic Network at a global level for the generation of products, such as precise orbits and satellite clocks. Furthermore, to accurately estimate geodetic coordinates, all errors involved with the propagation of GNSS signals and with ground stations must be properly modeled and treated. Thus, the main objective of this work is to evaluate the accuracy of the PPP-RTK Positioning Technique, using corrections from the Trimble Centerpoint RTX Service in Brazil. For this, GNSS surveys were carried out in all states of the Federation in Geodetic Stations belonging to the SGB, whose coordinates were considered as reference in the evaluation process. Student's t statistical tests were applied – to detect possible trends (systematic errors) in the data, and Chi-Square to assess the precision of the coordinates. Finally, the results show that the horizontal accuracy improves gradually with increasing convergence time, reaching 0.025m ± 0.018m (Trend and Precision) for 15 minutes of convergence.

Визначення еталонних напрямків на сертифікованому поліґоні з використанням GNSS вимірювань

This work examines the results of experimental GNSS measurements in 2022 performed at the points of the scientific geodetic range (NSG). The purpose of the research is to perform simultaneous GNSS measurements at four points of the reference linear base (ELB) section and to process experimental GNSS observations at points of the metrological calibrated geodetic network to determine reference azimuths and directional angles. Method. Experimental measurements were carried out using two frequency GNSS receivers with every second registration of signals and binding to the nearest permanent stations that are part of the International GNSS service: GEOTERRACE. The paper considers the application of the method of calculating azimuths using geodetic coordinates of points and parameters of reference ellipsoids. The results. Data processing of synchronous observations of points (ELB) and permanent stations was performed in the Leica Geo Office software complex. The value of the marginal error of determining the coordinates of the investigated points does not exceed 5 mm. The results of the calculations of the investigated azimuths for different coordinate systems and the accuracy of their determination are given. The parameters of the Krasovsky, WGS-84 and ITRF 2000 ellipsoid references were used for the calculations. The calculated values of the direction angles in the USK 2000 coordinate system for the six-degree zone. Scientific novelty. The possibility of using GNSS measurements for creating reference directions, determining their azimuths and directional angles is shown. An accuracy assessment was carried out based on the results of the measurements. The calculated accuracy of determining the azimuths of the directions depends on the accuracy of determining their coordinates and the distance between observation points. The obtained formula for calculating the accuracy of direction determination in angular units. Practical significance. The stability of the points calibrated by the metrological service of the ELB NHP section over time has been confirmed, which gives grounds for using the investigated directions as standards for calibration of navigation equipment. Calculated azimuths and direction angles of the selected directions for different coordinate reference systems. The calculated value of the convergence of the meridians for the six-degree zone of USK 2000 point P-1. The obtained values of true azimuths can be used to study the inclination of the magnetic needle.

Towards realizing a visual UAV flying environment: A novel approach based aerial imagery to construct a dataset for visual servoing

Realizing a visual flying environment in various scenarios is an instrumental key to establishing visual hardware-in-the-loop (HIL) simulation for flying UAVs. To simulate a desired UAV flying mission for a specific building landing in arbitrary geodetic coordinates, a new approach is presented. The approach fulfills the UAV landing HIL via three key elements: Building, Training, and Servoing. Building a flying dynamic scene which is not limited to a certain scenario, but can be utilized for generating different aerial remote sensing scenes according to desired geodetic coordinates (location-free), flying mission, perspective angles, and approaching velocities. The dynamic scene is constructed via RHINO graphics software based on georeferenced images taken at different altitudes. Training a deep detection framework on the extracted dataset from each constructed scene to localize a specific building as a landing platform. Servoing a pan–tilt camera on an embedded system by a pure image-based visual servoing (IBVS) method to coincide the detected building center with the acquired frame center during the flight. Tiny-YOLOv4 is picked as a light detector that runs on Nvidia nano with a servo kit and achieves a satisfactory result even with two wind disturbances models in a real-time condition. Thus, verifying a successful UAV landing on a specific building approach is accomplished.