GNSS Device Research Articles

Automated Derivation of Vine Objects and Ecosystem Structures Using UAS-Based Data Acquisition, 3D Point Cloud Analysis, and OBIA

This study delves into the analysis of a vineyard in Carinthia, Austria, focusing on the automated derivation of ecosystem structures of individual vine parameters, including vine heights, leaf area index (LAI), leaf surface area (LSA), and the geographic positioning of single plants. For the derivation of these parameters, intricate segmentation processes and nuanced UAS-based data acquisition techniques are necessary. The detection of single vines was based on 3D point cloud data, generated at a phenological stage in which the plants were in the absence of foliage. The mean distance from derived vine locations to reference measurements taken with a GNSS device was 10.7 cm, with a root mean square error (RMSE) of 1.07. Vine height derivation from a normalized digital surface model (nDSM) using photogrammetric data showcased a strong correlation (R2 = 0.83) with real-world measurements. Vines underwent automated classification through an object-based image analysis (OBIA) framework. This process enabled the computation of ecosystem structures at the individual plant level post-segmentation. Consequently, it delivered comprehensive canopy characteristics rapidly, surpassing the speed of manual measurements. With the use of uncrewed aerial systems (UAS) equipped with optical sensors, dense 3D point clouds were computed for the derivation of canopy-related ecosystem structures of vines. While LAI and LSA computations await validation, they underscore the technical feasibility of obtaining precise geometric and morphological datasets from UAS-collected data paired with 3D point cloud analysis and object-based image analysis.

Design of Autonomous Position and Secondary Estimation of Atmospheric Parameters Sensor Using Low-cost GNSS

The article focuses on the design and implementation of a Low-cost GNSS device for autonomous position monitoring and for determining parameters of the atmosphere. The first part is dedicated to the specification of individual components and their combination into several devices. The primary part includes a test of these GNSS devices and the parameters of data collection. This is followed by a quality test of these collected datasets, in several graphs is shown device capabilities. Also, we can see some problems with components, but we were able to specify what causes them. The final part deals with positioning and determining atmospheric parameters by G-Nut software with the selected GNSS sensor.

Evaluation of a GNSS for wave measurement and directional wave spectrum analysis

Wave buoys are important devices to monitor and analyze wave data for ocean and coastal engineering. A GNSS wave buoy is briefly introduced in the paper, which has high resolution to measure the buoy motion by vertical, north-south and west-east displacements and independent velocities in above three directions. Based on the displacements and velocities, statistical results, frequency spectra and directional spectra are analyzed, and results based on the displacements are compared with that from Waverider with a distance less than 6m deployed in the special sea water with the GNSS buoy. Wave profiles comparison show that GNSS buoy presented slightly large significant wave height and mean wave height due to its high sampling frequency, and resulted in smaller mean wave period than that from Waverider. Statisticaly, between the analyzing result of the GNSS and wave rider, the maximum error of wave height is about 5.5%; and the maximum difference of wave period is about 0.5s, when sampling frequency is similar. The energy spectra were basically consistent from these two devices. The peaks of directional spectra were similar but the spreading angle was smaller from GNSS. Results mean the GNSS device presents almost similar wave information to that from Waverider.

GNSS Real–Time Precise Point Positioning in Arctic Northeast Passage

Human activities in the Arctic regions have been increasing in recent years due to the impacts of climate change, such as Arctic Sea ice decline. For example, there has been an increase in Arctic shipping routes. A robust navigation system with a high positioning accuracy is required when traversing the extremely challenging Arctic environment to ensure the safety of human activities. However, the high–precision GNSS navigation and the positioning method, e.g., real–time kinematic (RTK), is not available in the polar regions due to the accessibility issues of the required infrastructures. On the other hand, the International GNSS Service (IGS) enables real–time applications; additionally, quick and convenient satellite communication systems are also available. This offers the possibility of real–time precise point positioning (RT–PPP) with multi–GNSS for high-precision navigation in the Arctic. In our paper, we analyzed the performance of multi–GNSS RT–PPP in the Arctic Northeast Passage (NEP), highlighting the following contributions: First, a GNSS device is installed on the M/V TIANHUI, which passed through the NEP from 10 September to 20 September 2019; Second, we quantitatively evaluated the collected GNSS signals in terms of the maximum satellite elevations, number of visible satellites (NSAT), position dilution of precision (PDOP) values, signal–to–noise ratio (SNR), and multipath errors. Third, we evaluated the accuracy of the CLK93 real–time products compared with the Deutsches GeoForschungsZentrum (GFZ) final products GBM. Finally, we carried out experiments for both single– (SF) and dual–frequency (DF) RT–PPP in the NEP during the 11–day testing period. Our experimental results show that meter–level positioning accuracy can be achieved with SF RT–PPP, while the DF RT–PPP model reaches sub–decimeter values and even centimeter–level accuracy. In addition, using the multi–GNSS method, we showed that the average RMS values of DF RT–PPP in the horizontal and vertical directions are 0.080 m and 0.057 m, respectively, demonstrating an improvement of approximately 70% over single–GPS solutions.

GENERATION OF REFERENCE VEHICLE TRAJECTORIES IN REAL-WORLD SITUATIONS USING AERIAL IMAGERY FROM A HELICOPTER

Abstract. Highly accurate reference vehicle trajectories are required in the automotive domain e. g. for testing mobile GNSS devices. Common methods used to determine reference trajectories are based on the same working principles as the device under test and suffer from the same underlying error problems. In this paper, a new method to generate reference vehicle trajectories in real-world situations using simultaneously acquired aerial imagery from a helicopter is presented. This method requires independent height information which is coming from a LIDAR DTM and the relative height of the GNSS device. The reference trajectory is then derived by forward intersection of the vehicle position in each image with the DTM. In this context, the influence of all relevant error sources were analysed, like the error from the LIDAR DTM, from the sensor latency, from the semi-automatic matching of the vehicle marking, and from the image orientation. Results show that the presented method provides a tool for creating reference trajectories that is independent of the GNSS reception at the vehicle. Moreover, it can be demonstrated that the proposed method reaches an accuracy level of 10 cm, which is defined as necessary for certification and validation of automotive GNSS devices.

UBLOX F9P FOR GEODETIC MEASUREMENT

This article brings knowledge of the settings of the Ublox ZED-F9P device, which will allow to use this receiver to build-up a simple low-cost GNSS device. The settings for the rover and base station functions are different and need to be done very accurately. Next we present a wiring scheme of the Ublox receiver with the Arduino system which as a whole device will enable the full functionality of the GNSS receiver as it is known from commonly used commercial devices. Ublox receiver was tested on accuracy and solution stability, results are shown in the article. At our department we create devices usable for teaching students as users or developers.

Investigation in designing and developing the GNSS positioning instrumentation used in measurement and mapping by CORS/RTK technology

Currently, in addition to GNSS receivers manufactured by foreign companies and imported into Vietnam, there are some domestically produced products with lower prices on the market. This paper presents an investigation on the design and development of a low-cost and high-precision GNSS device, used for CORS/RTK measurement in establishing topographic and cadastral maps. The developed GNSS device consists of a GNSS satellite antenna, a receiver, and an electronic field-book (using a smartphone device) installed with a self - developed software. The GNSS receiver is developed based on the technology and equipment of Drotek company (France). The components of the GNSS receiver have been selected and designed with functionality for both dynamic and static measurement modes. The GNSS receiver and electronic field-book are connected wirelessly via the Bluetooth module, allowing convenient operation with the receiver. Experiments were conducted to measure the parallel points of an established geodetic network using GPS technology. The possitioning data was measured by two receivers, South’s S82 (China) and self-developed KX20-R, using RTK method with a single CORS station installed at the University of Mining and Geology. The results showed that the developed GNSS positioning device provides an accuracy of centimeters and completely meet the requirements of large-scale topographic and cadastral surveying and mapping.

Performance and Micro-Pacing Strategies in a Freestyle Cross-Country Skiing Distance Race.

This study examined the micro-pacing strategies during a distance freestyle cross-country (XC) skiing competition. Nine female and 10 male highly trained XC skiers wore a GNSS device during a FIS-sanctioned race. The course was ~4900 m; women completed two-laps; men completed three-laps. The course was divided into uphill (S1, S3, S5, S7), downhill (S2, S4, S6, S8), and flat (S9) sections for analyses. Statistical parametric mapping was used to determine the course positions (clusters) where total race time or section time was significantly associated with instantaneous skiing speed. Total race time was associated with instantaneous skiing speed during a cluster in S1 on lap 2 for both sexes (t ≥ 5.899, p ≤ 0.008). The two longest uphill sections (S1; S5) and the flat section (S9) contained clusters where section times were related to instantaneous skiing speed for both sexes (p < 0.05). The fastest woman gained 6.9 s on the slowest woman during a cluster in S1 on lap 1 and 7.3 s during a cluster in S9 on lap 1. The fastest man gained 51.7 s on the slowest man over all clusters in S5 over the 3 laps combined. Compared to skiers with longer total race times, skiers with shorter race times skied with faster instantaneous speeds in some clusters of the uphill sections, as well as on the flat section of the course. This study also identified different relative micro-pacing strategies for women and men during freestyle distance XC skiing races. Finally, statistical parametric mapping analyses can help to identify individual strengths and weaknesses for guiding training programs and optimise competition pacing strategies.

人物計測のためのビデオカメラ間およびビデオカメラとGNSSの時刻同期に関する研究

In Japan, towards the Tokyo Olympics and Paralympics, the Japan Sports Agency has been founded, and policies related to training athletes and improving competitiveness are being promoted. To achieve these policies, many researches use AI technology to analyze sports data gathered by video cameras and IoT devices. To make effective use of those data, it is necessary to manage them with a unified time stamp. However, it is difficult to unify the time stamp because these devices are not linked to each other. To solve this problem, the time synchronization is often adopted manually, but it costs a lot of manpower. Therefore, in this research, we firstly organize the problems of time synchronization between video cameras and between video cameras and GNSS device by investigating existing researches. And then, we propose an efficient and highly accurate time synchronization technologies that can solve these problems.

An Online Stream Monitoring Algorithm for Fraud Detection in the Transport of Goods

The process of monitoring vehicles used in road transports plays an important role in detecting fraud committed by drivers. Algorithm designers face a number of challenges, including large number of vehicles monitored, demands related to online calculations, and ability to easily explain fraud alarms triggered to supervisors who make final decisions about actions to be taken. In this paper, we propose rather general, lightweight stream, online heuristics. The vehicle’s position is periodically controlled by a GNSS device. The algorithm detects potential illegal activities along the route between the origin and the destination. Anomalies in the vehicle’s trajectory are detected, based on a multi-resolution analysis of the economy of routes. The economy metric is easily understood and verifiable by controllers. The solution is also capable of identifying clearly suspicious trajectories that popular geofencing approaches would overlook. The scale on which the solution may be adopted is obtained thanks to the stream – like nature of the algorithm: essentially, the resources used do not increase along with the size of the input stream (the number of GNSS frames generated for the vehicle). An experiment illustrating the algorithm’s viability is presented as well.

Real-time precise point positioning with a low-cost dual-frequency GNSS device

In recent years, there is an increasing demand for precise positioning with low-cost GNSS devices in support of applications from self-driving cars to unmanned aerial vehicles. Although single-frequency GNSS devices are still dominant in the low-cost market to date, some GNSS manufacturers have released low-cost dual-frequency GNSS devices, which are able to track new civilian signals such as L2C or L5. With dual-frequency GNSS measurements, the ionospheric delays can be eliminated by forming ionospheric-free combinations to further improve the positioning accuracy and reliability with low-cost GNSS devices. Extensive work has been conducted in the past for precise point positioning using high-end dual-frequency GNSS receivers. For low-cost GNSS-based PPP, there are some issues that need to be addressed. One is that current low-cost dual-frequency receivers can track only civil signals but not all GPS satellites currently transmit L2C or L5 civil signals. This means that fewer dual-frequency GNSS measurements are available for position determination. Another is that the measurement quality of low-cost receivers is not as good as high-end receivers. The above will not only increase the convergence time but also affect the obtainable positioning accuracy. We propose a new method in which not only the conventional dual-frequency ionospheric-free code and phase measurements, but also the single-frequency ionosphere-corrected code measurements with precise ionospheric products, are adopted for position determination. To be more specific, ionospheric-free code and phase combinations are applied to satellites with the second civil signal, while the single-frequency ionosphere-corrected code measurement is applied to all observed satellites. Both stationary and automotive experiments have been conducted to assess the performance of the new method. The field test results show that it can quickly reach half-meter accuracy in horizontal at a much faster convergence speed than the conventional DF-PPP which would usually take several minutes to reach a similar accuracy. This indicates that the new method is more suitable for mass-market applications with low-cost GNSS devices.

Utilização de Veículos Aéreos Não Tripulado no Monitoramento da Dinâmica Sedimentar de Praias Expostas

O uso de veículos aéreos não tripulados (VANT), popularmente conhecidos por drones, têm sido utilizados com frequência em diversos setores, como segurança pública, fiscalização ambiental, pesquisa, agricultura e no monitoramento de ambientes naturais diversos. O monitoramento da dinâmica sedimentar de duas porções distintas da Praia de Navegantes (SC), Brasil – a porção Sul, em processo de recuperação há dez anos, e um trecho da porção Norte, Praia do Gravatá, em avançado processo de degradação – foi realizado entre os meses de abril e julho de 2019 com a utilização de um VANT. Foram realizados seis sobrevoos em cada um dos locais estudados. A aerofotogrametria desses locais foi realizada a uma altura pré-definida de 100 metros, tendo sido registrada por meio de memorial de processamento com a sobreposição lateral de 65% e frontal de 75% entre as imagens obtidas. As imagens de cada levantamento foram tratadas no software Agisoft PhotoScan com aplicação de pontos de apoio materializados em solo georreferenciados com emprego de aparelho GPS/GNSS, marca Geomax, Modelo Zenith 25, na qual os mesmos (pontos) foram pós-processados com base na Rede Brasileira de Monitoramento Contínuo (RBMC) do Instituto Brasileiro de Geografia e Estatística (IBGE). Foram geradas ortofotos georreferenciadas, imagens 3D com geração de curvas de nível com intervalos de 0,25 m, o que possibilitou calcular os volumes de sedimentos erodidos ou acrescidos. O método proposto demanda ainda de alguns ajustes e aprimoramento, mas demonstrou grande eficácia no monitoramento do processo de dinâmica sedimentar nos locais estudados.

The costs of retrofitting smart tachographs in HDVS in European Union

The paper focuses on the costs connected with the idea of retrofitting smart tachographs in all heavy duty vehicles in the European Union. Such a motion has been proposed, in order to increase the road safety. The new class of tachographs, ie. the smart tachographs are supposed to be fitted with a GNSS device ensuring a constant monitoring of the vehicle’s speed and other parameters but also a transmitter which should allow to send data in real time without the necessity to download the data manually. However, such a vast process will generate severe costs for the Member States’ administration but also for private companies which will need to handle the cost of fitting the device in their vehicles. The purpose of the article is to estimate this cost.

Influence of Different Route-choice Decision Modes

Abstract More and more drivers use GPS based tools (GNSS) to plan their route in order to choose the optimum route (shorter, faster or the most economical). These GNSS devices can operate offline or online. Off-line, when the GIS database is installed in the device and there is not any information regarding the actual traffic flow, in that case the program always calculates the same route between two places. Online, when the actual traffic flow information is available, in that case there is the possibility of the calculation of the optimal route in real time. Based on the above options, the driver’s route-choice decision can be static, dynamic or informed. Static, when the driver always follows the same route: either without using a GNSS device (choosing the usual way) or with an offline device. Dynamic, when the driver chooses the way conforming to only real time visual information on the spot without any navigation tool or external information, and decides according to traffic density. Informed, when the GNSS device calculates the optimal route in line with the current traffic flow information. The aim of this study is the present the influence of the proportion of different route-choice decision modes.

UNMANNED AERIAL VEHICLE USE FOR WOOD CHIPS PILE VOLUME ESTIMATION

Abstract. The rapid development of unmanned aerial vehicles is a challenge for applied research. Many technologies are developed and then researcher are looking up for their application in different sectors. Therefore, we decided to verify the use of the unmanned aerial vehicle for wood chips pile monitoring. We compared the use of GNSS device and unmanned aerial vehicle for volume estimation of four wood chips piles. We used DJI Phantom 3 Professional with the built-in camera and GNSS device (geoexplorer 6000). We used Agisoft photoscan for processing photos and ArcGIS for processing points. Volumes calculated from pictures were not statistically significantly different from amounts calculated from GNSS data and high correlation between them was found (p = 0.9993). We conclude that the use of unmanned aerial vehicle instead of the GNSS device does not lead to significantly different results. Tthe data collection consumed from almost 12 to 20 times less time with the use of UAV. Additionally, UAV provides documentation trough orthomosaic.

UNMANNED AERIAL VEHICLE USE FOR WOOD CHIPS PILE VOLUME ESTIMATION

The rapid development of unmanned aerial vehicles is a challenge for applied research. Many technologies are developed and then researcher are looking up for their application in different sectors. Therefore, we decided to verify the use of the unmanned aerial vehicle for wood chips pile monitoring. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt; We compared the use of GNSS device and unmanned aerial vehicle for volume estimation of four wood chips piles. We used DJI Phantom 3 Professional with the built-in camera and GNSS device (geoexplorer 6000). We used Agisoft photoscan for processing photos and ArcGIS for processing points. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt; Volumes calculated from pictures were not statistically significantly different from amounts calculated from GNSS data and high correlation between them was found (p = 0.9993). We conclude that the use of unmanned aerial vehicle instead of the GNSS device does not lead to significantly different results. Tthe data collection consumed from almost 12 to 20 times less time with the use of UAV. Additionally, UAV provides documentation trough orthomosaic.

Study on the Spread, Biomass Production, and Nutrient Content of Ragweed with High-Precision GNSS and GIS Device System

One of the important issues in agroenvironmental protection today is the pollen emission of common ragweed (Ambrosia artemisiifolia L.). A decrease in pollen emission can only be achieved if we have adequate knowledge of ragweed's biology, its spread, and the dynamic processes of the population. The damage this weed affords is important from both a human health and plant protection point of view. Winter wheat is an important crop in Hungary, being seeded on approximately 1.2–1.3 million ha annually. The present research investigates the spread of ragweed in cereal stubble fields, its nutrient content, and its water uptake. Three weeks after the harvest of winter wheat, A. artemisiifolia was present in the area in high density. Young ragweed plants absorbed the most potassium and nitrogen. Average potassium and nitrogen contents were 6.0 and 5.8 kg ha−1, respectively. Phosphorus content was 1.1 kg ha−1, and A. artemisiifolia also absorbed a significant quantity of calcium. Average calcium content was 3.85 kg ha−1.