Real-time Kinematic Technology Research Articles

Next generation gravel road profiling – The potential of advanced UAV drone in comparison with road surface tester and rotary laser levels

Over the last decades, significant progress has been made and new approaches have been proposed for efficient collection of road condition data. Gravel roads are crucial for connecting urban and rural areas in Sweden, constituting a significant portion of the road network. Therefore, this study addresses the use of a developed Unmanned Aerial Vehicle (UAV)-based digital imaging system focusing on efficient collection of surface condition data over gravel roads.The study focuses on in-situ profile measurements of a gravel road located in Trosa, Sweden, using three different profiling methods: UAV drone with RTK technology, Road Surface Tester (RST), and Rotary Laser Level (RLL) to explore the agreement between these methods.The UAV drone, equipped with Real-Time Kinematic (RTK) technology, captures high-resolution images to produce detailed 3D surface models, overcoming the challenges posed by adverse weather conditions. Notable outcomes reveal RTK technology's stability, maintaining a steady 3D position accuracy below 2 cm. To enhance synchronization and comparison between different profiling methods, efforts should be made to standardize coordinate systems and measurement analysis software.Minimum average absolute differences of 1.1 cm, 1 cm, and 0.7 cm were recorded for all profiles (from 1 m left to 1 m right of the road centerline) in the comparisons between UAV drone – RST, UAV drone – RLL, and RST – RLL methods, respectively. This underlines the significant advancement in UAV drone technology, enabling remarkably accurate measurements of vertical offsets for profiling the tested gravel road despite the high altitude at which the UAV drone operates.

Accuracy Assessment of UAV Photogrammetry System with RTK Measurements for Direct Georeferencing

Abstract. The direct georeferencing accuracy of unmanned aerial vehicle (UAV) images with real-time kinematic (RTK) measurements is a concerned topic in the community of photogrammetry. This study assesses the capabilities of a multi-rotor platform equipped with RTK technology, specifically a DJI Phantom 4 RTK UAV, for robust direct georeferencing. The UAV surveyed a square and a building at Wuhan University to assess the accuracy and spatial consistency of direct georeferencing in close-range photography. We tested checkpoint errors under various ground control points (GCPs) configurations. The results show that without GCP, an analysis of 71 spatially distributed checkpoints produced a root mean square error (RMSE) of 5.58 cm in the Z direction. This finding indicates that RTK-equipped UAVs can achieve acceptable error margins even without using GCPs, thereby fulfilling the precision requirements for large-scale mapping.

Research on the Model Predictive Trajectory Tracking Control of Unmanned Ground Tracked Vehicles

This article summarizes the research significance and the development status of the unmanned ground tracked vehicles (UGTVs). According to the speed and steering principle of the UGTVs in plane motion, the kinematic state space equation of the vehicle is established. Based on the model predictive control (MPC), the UGTVs trajectory tracking controller is also established. After introducing the overall control system solution, based on the vehicle model, the track speed on both sides is used as the control input to solve the predicted output of the system. After constraining the control amount, the model prediction controller is established by using S function. Several simulations with different preset speeds are performed under linear conditions, and the numerical simulation with different prediction time domains and control time domains are performed under continuous curves. The test validates the effectiveness of the controller, and the effects of speed and time domain parameters on the deviation are analyzed based on the results. Based on satellite positioning technology, trajectory tracking tests of the UGTVs are carried out. After analyzing the positioning principle and common errors, the real-time kinematic technology is used to improve the positioning accuracy of the vehicle prototype. The hardware of the test platform includes a data acquisition system, a control execution system and a walking execution system, and the software part includes data processing and optimization control. The trajectory tracking experiments under different driving conditions are conducted, and the results show that the navigation tracking system can achieve good tracking performance.

Accuracy of Aerial Photoscanning with Real-Time Kinematic Technology

<div class="section abstract"><div class="htmlview paragraph">Photoscanning photogrammetry is a method for obtaining and preserving three-dimensional site data from photographs. This photogrammetric method is commonly associated with small Unmanned Aircraft Systems (sUAS) and is particularly beneficial for large area site documentation. The resulting data is comprised of millions of three-dimensional data points commonly referred to as a point cloud. The accuracy and reliability of these point clouds is dependent on hardware, hardware settings, field documentation methods, software, software settings, and processing methods. Ground control points (GCPs) are commonly used in aerial photoscanning to achieve reliable results. This research examines multiple GCP types, flight patterns, software, hardware, and a ground based real-time kinematic (RTK) system. Multiple documentation and processing methods are examined and accuracies of each are compared for an understanding of how capturing methods will optimize site documentation.</div></div>

Test Method of Real-time Kinematic and Its Application in Terminal Positioning Performance test

The real-time kinematic technology has been widely used in positioning terminals. The principle, test method of the real-time kinematic technology and its application in terminal positioning test are presented in this paper. A virtual drive test system is developed by using the real-time kinematic technology, and the positioning performance of the terminal is tested under different road sections. The test results show that the system can evaluate the terminals performance under the real application scenarios very well.

Reduction of environmental pollution by using RTK-navigation in

The concept of precision farming is wide, and it represents the efficiency which is achieved with the help of precision. For the navigation of field machines, the RTK (Real Time Kinematic) navigation is needed. In order to verify the positive effects in practice, RTK navigation system equipped with Fentd 828 was applied to test the width of overlap, and fuel and time that could be saved compared with manual driving. The experiment was conducted on two areas of land size of 172 m × 58 m with two working machines width 3 m and 6 m. Results indicated that 15.7% of the time and 8.66% of the fuel were saved on a working machine of 3 meters width, and 12.6% of the time and 8.28% of the fuel were saved on a working machine of 6 m width. The width of the overlap represent 10% of the working width of the machine, and with the method of turning, which RTK navigation allows, additional time was saved. Ecological footprint, CO2 emissions and global warming potential (GWP) was estimated under different guiding systems. The largest footprint was related to manual tillage with 3 m width working machine, while estimation on CO2 (kg) emissions and GWP obtained the same result. The use of precision agriculture technologies allows better planning and analyzing of working procedures. The air, water and soil pollution are less intensive. Keywords: precision farming, RTK technology, ecological footprint, environmental pollution, tillage DOI: 10.25165/j.ijabe.20191205.4932 Citation: Kelc D, Stajnko D, Berk P, Rakun J, Vindis P, Lakota M. Reduction of environmental pollution by using RTK-navigation in soil cultivation. Int J Agric & Biol Eng, 2019; 12(5): 173–178.

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.

Reduction of environmental pollution by using RTK-navigation in soil cultivation

The concept of precision farming is wide, and it represents the efficiency which is achieved with the help of precision. For the navigation of field machines, the RTK (Real Time Kinematic) navigation is needed. In order to verify the positive effects in practice, RTK navigation system equipped with Fentd 828 was applied to test the width of overlap, and fuel and time that could be saved compared with manual driving. The experiment was conducted on two areas of land size of 172 m × 58 m with two working machines width 3 m and 6 m. Results indicated that 15.7% of the time and 8.66% of the fuel were saved on a working machine of 3 meters width, and 12.6% of the time and 8.28% of the fuel were saved on a working machine of 6 m width. The width of the overlap represent 10% of the working width of the machine, and with the method of turning, which RTK navigation allows, additional time was saved. Ecological footprint, CO2 emissions and global warming potential (GWP) was estimated under different guiding systems. The largest footprint was related to manual tillage with 3 m width working machine, while estimation on CO2 (kg) emissions and GWP obtained the same result. The use of precision agriculture technologies allows better planning and analyzing of working procedures. The air, water and soil pollution are less intensive. Keywords: precision farming, RTK technology, ecological footprint, environmental pollution, tillage DOI: 10.25165/j.ijabe.20191205.4932 Citation: Kelc D, Stajnko D, Berk P, Rakun J, Vindiš P, Lakota M. Reduction of environmental pollution by using RTK-navigation in soil cultivation. Int J Agric & Biol Eng, 2019; 12(5): 173–178.

GPS RTK定位技术在驾考系统中的应用

全球定位系统(GPS)因其高精度三维定位测速及定时的功能在精密工程测量中得到迅速广泛的应用。利用高精度GPS载波相位实时动态差分(RTK)定位技术的特点，在机动车驾驶技能考试中，可精确地计算考车的轮廓位置点，解决了考车行驶过程中的距离测量问题。根据RTK技术在考车上架设的双GPS天线和具体考试项目里车线之间距离的检测方法，并结合考场电子地图各项目的特征点和各项目的评判规则，华众设计的全自动智能驾考系统，可实现精确评判。 Global positioning system (GPS) has been widely used in precision engineering measurement be-cause of its high precision three dimensional positioning velocity test and timing function. Using the characteristics of high precision GPS real-time kinematic (RTK) positioning technology in the motor vehicle driving skills test can accurately calculate the contour points of the test vehicle, this solves the problem of distance measurement in the course of test vehicle. Based on RTK Technology in the test vehicle mounted dual GPS antenna and the detection method of the distance between the test vehicle and the line in the examination of specific project, and combined with the examination of electronic map the feature points and the purposes of evaluation rules, Huazhong design the automatic intelligence of the driving test system , which can realize accurate judgment.

RTK Mobile Machine Control--Assessing Partial Sky Blockage with GIS

Effective Real Time Kinematic (RTK) mobile machine control requires a sufficient number of global positioning system (GPS) satellites that are both visible and suitably positioned. Reliably obtaining the highest degree of accuracy and precision afforded by RTK technology requires the initial acquiring of a solution (i.e., obtaining an RTK fix solution), the maintaining of the RTK fix solution, and if it is lost, rapidly reestablishing the RTK fix solution. Losing the RTK fix solution is a common occurrence when operating near trees, tall landforms, and large structures that can cause significant sky blockage. Operators can increase the likelihood of acquiring and maintaining an RTK fix solution by incorporating more satellites from multi-national Global Navigation Satellite System (GNSS) constellations. However, this added capability is only of practical economic benefit when and if operating near sky blockages. Due to the additional expense in upgrading mobile machine control to full GNSS coverage capabilities, upgrade considerations should include the impact of sky blockages surrounding production fields caused by the rolling terrain, nearby landforms, and most importantly, field-surrounding tree canopies.

Reliable and Redundant RTK Positioning for Applications in Hard Observational Conditions

Reliable and Redundant RTK Positioning for Applications in Hard Observational ConditionsIt is well known that RTK (Real Time Kinematic) positioning is a very efficient technique for determination of coordinates in real time, directly on location. Although this technique has been well known since the mid-nineties of the last century, the common use of this technique developed since permanent reference GNSS (Global Navigation Satellite Systems) stations started operating as the national reference systems. Positioning in real time is very convenient for users who do not need to know any advanced technique of post-processing, especially in cases when no obstructions exist around the measured point exist. However, in practice, there are some situations when the use of RTK technique makes some difficulties, especially if the GNSS receiver has no full availability of satellites. Obstructions caused by trees, buildings, power lines etc. limit satellite availability and in consequence decrease the reliability of determined coordinates significantly. In those situations gross errors of even meters can appear in RTK positioning. In order to avoid misleading coordinates occurring we can use more than one RTK receiver simultaneously. The paper presents an approach to the RTK technology based on the simultaneous use of three different RTK receivers. Three different GNSS/RTK receivers can be set on a special mounting beam and additionally RTK positions are sent in real time to a computer. The computer software analyses not only the precision but also checks the accuracy and reliability of the RTK positions determined. Consequently, the new approach to RTK survey presented can allow obtaining reliable coordinates of centimeter accuracy even under very severe forest conditions.

Performance of RTK Positioning in Forest Conditions: Case Study

This paper presents the performance of the real-time kinematic (RTK) technique in very severe conditions. The measurements were conducted in forest conditions during two different experiments. Two Global Positioning System receivers were used: an Ashtech Z-Surveyor and a Z-Xtreme. Radiomodems were used for transmitting RTK corrections from a reference station to a rover. The RTK measurements were performed during quite good satellite configuration. The use of RTK technology, based on the Ashtech Z-Xtreme receiver as a rover in forest terrain, allowed centimeter accuracy to be obtained. However, practical experiments showed that there is a need for redundant independent RTK solutions based on repeated independent ambiguity reinitializations. Although gross errors might occur, the RTK technique can be very helpful technology for centimeter positioning in woodland areas.