scholarly journals Methodology for the Correction of the Spatial Orientation Angles of the Unmanned Aerial Vehicle Using Real Time GNSS, a Shoreline Image and an Electronic Navigational Chart

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2810
Author(s):  
Krzysztof Naus ◽  
Piotr Szymak ◽  
Paweł Piskur ◽  
Maciej Niedziela ◽  
Aleksander Nowak

Undoubtedly, Low-Altitude Unmanned Aerial Vehicles (UAVs) are becoming more common in marine applications. Equipped with a Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) receiver for highly accurate positioning, they perform camera and Light Detection and Ranging (LiDAR) measurements. Unfortunately, these measurements may still be subject to large errors-mainly due to the inaccuracy of measurement of the optical axis of the camera or LiDAR sensor. Usually, UAVs use a small and light Inertial Navigation System (INS) with an angle measurement error of up to 0.5∘ (RMSE). The methodology for spatial orientation angle correction presented in the article allows the reduction of this error even to the level of 0.01∘ (RMSE). It can be successfully used in coastal and port waters. To determine the corrections, only the Electronic Navigational Chart (ENC) and an image of the coastline are needed.

Author(s):  
Lương Ngọc Dũng ◽  
Trần Đình Trọng ◽  
Vũ Đình Chiều ◽  
Bùi Duy Quỳnh ◽  
Hà Thị Hằng ◽  
...  

Giải pháp thành lập bản đồ địa hình bằng thiết bị bay không người lái (Unmanned Aerial Vehicle - UAV) đang ngày càng phổ biến ở Việt Nam. Đã có nhiều nghiên cứu chứng minh thiết bị UAV đảm bảo độ chính xác thành lập bản đồ địa hình tỷ lệ lớn, tuy nhiên chưa có các giải pháp cụ thể cho công trình đặc thù dạng tuyến. Mục tiêu nghiên cứu của bài báo là các chế độ bay phù hợp cho công tác khảo sát địa hình các công trình dạng tuyến. Đối tượng thực nghiệm, một đoạn đường bộ thuộc địa phận đê Xuân Quan, Hà Nội, được khảo sát bằng thiết bị UAV Phantom 4 Pro với các chế độ khác nhau trên các phần mềm điều khiển bay có sẵn. Kết quả thực nghiệm các chế độ bay được so sánh với kết quả đo định vị động thời gian thực (Global Navigation Satellite System/Real Time Kinematic - GNSS/RTK) để đánh giá độ chính xác. Nghiên cứu chỉ ra kiểu bay dải phủ trùm, đối với công trình dạng tuyến, thích hợp ở các giai đoạn thiết kế kỹ thuật và thiết kế thi công. Trong khi kiểu bay 2 dải đơn phù hợp và hiệu quả cho các quá trình quy hoạch, đánh giá sơ bộ công trình dạng tuyến.


2020 ◽  
Vol 12 (19) ◽  
pp. 3185
Author(s):  
Ehsan Khoramshahi ◽  
Raquel A. Oliveira ◽  
Niko Koivumäki ◽  
Eija Honkavaara

Simultaneous localization and mapping (SLAM) of a monocular projective camera installed on an unmanned aerial vehicle (UAV) is a challenging task in photogrammetry, computer vision, and robotics. This paper presents a novel real-time monocular SLAM solution for UAV applications. It is based on two steps: consecutive construction of the UAV path, and adjacent strip connection. Consecutive construction rapidly estimates the UAV path by sequentially connecting incoming images to a network of connected images. A multilevel pyramid matching is proposed for this step that contains a sub-window matching using high-resolution images. The sub-window matching increases the frequency of tie points by propagating locations of matched sub-windows that leads to a list of high-frequency tie points while keeping the execution time relatively low. A sparse bundle block adjustment (BBA) is employed to optimize the initial path by considering nuisance parameters. System calibration parameters with respect to global navigation satellite system (GNSS) and inertial navigation system (INS) are optionally considered in the BBA model for direct georeferencing. Ground control points and checkpoints are optionally included in the model for georeferencing and quality control. Adjacent strip connection is enabled by an overlap analysis to further improve connectivity of local networks. A novel angular parametrization based on spherical rotation coordinate system is presented to address the gimbal lock singularity of BBA. Our results suggest that the proposed scheme is a precise real-time monocular SLAM solution for a UAV.


Author(s):  
E. Tufarolo ◽  
C. Vanneschi ◽  
M. Casella ◽  
R. Salvini

<p><strong>Abstract.</strong> Open pit mines localized in high mountains are probably one of the most complex environments for Structure-From-Motion (SfM) based photogrammetry. The case study presented in this paper refers to the realization of a detailed topographic mapping in the Torano marble basin (Apuan Alps, Italy) which needed, after decades of excavation activity, a new topographic survey.</p><p>Given the requested very high resolution, the time constraints and safety-related problems, a photogrammetric approach by a fixedwing Unmanned Aerial Vehicle (UAV) was chosen to carry out thesurvey of the basin. In addition, given the morphological complexity of the area, characterized by extreme steep slopes more than hundreds of meters high, and the necessity to minimize the fieldwork without sacrificing the work quality, an UAV equipped with a L1/L2 Network Real Time Kinematic (NRTK) Global Navigation Satellite System (GNSS) was used.</p><p>The scope of this work is to compare the accuracy of UAV derived 3D photogrammetric models realized with different approaches: by using traditional Ground Control Points (GCPs), by using the on-board Network Real Time Kinematic system for camera position detection, and a mix of both. At the end, we tested the quality of the models to verify the reachable levels of accuracy.</p>


2021 ◽  
pp. 1-13
Author(s):  
Jonghyuk Kim ◽  
Jose Guivant ◽  
Martin L. Sollie ◽  
Torleiv H. Bryne ◽  
Tor Arne Johansen

Abstract This paper addresses the fusion of the pseudorange/pseudorange rate observations from the global navigation satellite system and the inertial–visual simultaneous localisation and mapping (SLAM) to achieve reliable navigation of unmanned aerial vehicles. This work extends the previous work on a simulation-based study [Kim et al. (2017). Compressed fusion of GNSS and inertial navigation with simultaneous localisation and mapping. IEEE Aerospace and Electronic Systems Magazine, 32(8), 22–36] to a real-flight dataset collected from a fixed-wing unmanned aerial vehicle platform. The dataset consists of measurements from visual landmarks, an inertial measurement unit, and pseudorange and pseudorange rates. We propose a novel all-source navigation filter, termed a compressed pseudo-SLAM, which can seamlessly integrate all available information in a computationally efficient way. In this framework, a local map is dynamically defined around the vehicle, updating the vehicle and local landmark states within the region. A global map includes the rest of the landmarks and is updated at a much lower rate by accumulating (or compressing) the local-to-global correlation information within the filter. It will show that the horizontal navigation error is effectively constrained with one satellite vehicle and one landmark observation. The computational cost will be analysed, demonstrating the efficiency of the method.


2021 ◽  
Vol 14 (2) ◽  
pp. 105
Author(s):  
Maelckson Bruno Barros Gomes ◽  
André Luis Silva Santos

<p class="04CorpodoTexto">Este artigo tem por objetivo aplicar geotecnologias para obtenção de informações planialtimétricas a fim de avaliar a viabilidade de implantação do campus Centro Histórico/Itaqui-Bacanga do IFMA. Considerando que para realização de levantamento por métodos tradicionais é recomendado que seja realizado o destocamento e a limpeza do terreno previamente, avaliou-se a realização do levantamento planialtimétrico a partir de um par de receptores <em>Global Navigation Satellite System</em> (GNSS) pelo método <em>Real Time Kinematic</em> (RTK) pós processado e também a partir da realização de levantamento fotogramétrico, utilizando aeronave remotamente pilotada (ARP), popularmente conhecida como drone. Esta análise permitiu demonstrar que o aerolevantamento com a ARP pode ser aplicado na concepção inicial de um projeto de engenharia, conforme classificação do Tribunal de Contas da União (TCU) para níveis de precisão, pois obteve-se uma diferença orçamentária de 19% entre os projetos elaborados a partir das duas geotecnologias.</p><div> </div>


2016 ◽  
Vol 12 (03) ◽  
pp. 64
Author(s):  
Haifeng Hu

Abstract—An online automatic disaster monitoring system can reduce or prevent geological mine disasters to protect life and property. Global Navigation Satellite System receivers and the GeoRobot are two kinds of in-situ geosensors widely used for monitoring ground movements near mines. A combined monitoring solution is presented that integrates the advantages of both. In addition, a geosensor network system to be used for geological mine disaster monitoring is described. A complete online automatic mine disaster monitoring system including data transmission, data management, and complex data analysis is outlined. This paper proposes a novel overall architecture for mine disaster monitoring. This architecture can seamlessly integrate sensors for long-term, remote, and near real-time monitoring. In the architecture, three layers are used to collect, manage and process observation data. To demonstrate the applicability of the method, a system encompassing this architecture has been deployed to monitor the safety and stability of a slope at an open-pit mine in Inner Mongolia.


Author(s):  
George K. Chang ◽  
Kiran Mohanraj ◽  
William A. Stone ◽  
Daniel J. Oesch ◽  
Victor (Lee) Gallivan

Intelligent compaction (IC) is an emerging technology with rollers equipped with global navigation satellite system (GNSS), an accelerometer-based measurement system, and an onboard color-coded display for real-time monitoring and compaction control. Paver-mounted thermal profiling (PMTP) is used to monitor asphalt surface temperatures behind a paver with a thermal scanner, and to track paver speeds, stops, and stop durations. Leveraging both IC and PMTP technologies allows for paving and compaction controls in real time, and for executing appropriate adjustments as needed. A case study is used to demonstrate the advantage of using both IC and PMTP over conventional operations. Postconstruction asphalt coring and tests, as well as pavement profile surveys were conducted to provide asphalt density data and pavement smoothness acceptance data for comparison and correlation analysis with IC and PMTP data. The data from 2 days of operations, one without the Material Transfer Vehicle (MTV) and another with the MTV, were analyzed and compared to illustrate the benefits of using IC, PMTP, and MTV for producing quality pavement products. Durability and smoothness are two key construction qualities for agencies and users of hot mix asphalt (HMA) pavements. These two factors also affect the long-term structural and functional pavement performance.


2018 ◽  
Vol 71 (4) ◽  
pp. 769-787 ◽  
Author(s):  
Ahmed El-Mowafy

Real-time Precise Point Positioning (PPP) relies on the use of accurate satellite orbit and clock corrections. If these corrections contain large errors or faults, either from the system or by meaconing, they will adversely affect positioning. Therefore, such faults have to be detected and excluded. In traditional PPP, measurements that have faulty corrections are typically excluded as they are merged together. In this contribution, a new PPP model that encompasses the orbit and clock corrections as quasi-observations is presented such that they undergo the fault detection and exclusion process separate from the observations. This enables the use of measurements that have faulty corrections along with predicted values of these corrections in place of the excluded ones. Moreover, the proposed approach allows for inclusion of the complete stochastic information of the corrections. To facilitate modelling of the orbit and clock corrections as quasi-observations, International Global Navigation Satellite System Service (IGS) real-time corrections were characterised over a six-month period. The proposed method is validated and its benefits are demonstrated at two sites using three days of data.


2019 ◽  
Vol 11 (3) ◽  
pp. 311 ◽  
Author(s):  
Wenju Fu ◽  
Guanwen Huang ◽  
Yuanxi Zhang ◽  
Qin Zhang ◽  
Bobin Cui ◽  
...  

The emergence of multiple global navigation satellite systems (multi-GNSS), including global positioning system (GPS), global navigation satellite system (GLONASS), Beidou navigation satellite system (BDS), and Galileo, brings not only great opportunities for real-time precise point positioning (PPP), but also challenges in quality control because of inevitable data anomalies. This research aims at achieving the real-time quality control of the multi-GNSS combined PPP using additional observations with opposite weight. A robust multiple-system combined PPP estimation is developed to simultaneously process observations from all the four GNSS systems as well as single, dual, or triple systems. The experiment indicates that the proposed quality control can effectively eliminate the influence of outliers on the single GPS and the multiple-system combined PPP. The analysis on the positioning accuracy and the convergence time of the proposed robust PPP is conducted based on one week’s data from 32 globally distributed stations. The positioning root mean square (RMS) error of the quad-system combined PPP is 1.2 cm, 1.0 cm, and 3.0 cm in the east, north, and upward components, respectively, with the improvements of 62.5%, 63.0%, and 55.2% compared to those of single GPS. The average convergence time of the quad-system combined PPP in the horizontal and vertical components is 12.8 min and 12.2 min, respectively, while it is 26.5 min and 23.7 min when only using single-GPS PPP. The positioning performance of the GPS, GLONASS, and BDS (GRC) combination and the GPS, GLONASS, and Galileo (GRE) combination is comparable to the GPS, GLONASS, BDS and Galileo (GRCE) combination and it is better than that of the GPS, BDS, and Galileo (GCE) combination. Compared to GPS, the improvements of the positioning accuracy of the GPS and GLONASS (GR) combination, the GPS and Galileo (GE) combination, the GPS and BDS (GC) combination in the east component are 53.1%, 43.8%, and 40.6%, respectively, while they are 55.6%, 48.1%, and 40.7% in the north component, and 47.8%, 40.3%, and 34.3% in the upward component.


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