scholarly journals A Test on the Potential of a Low Cost Unmanned Aerial Vehicle RTK/PPK Solution for Precision Positioning

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3882
Author(s):  
Nicola Angelo Famiglietti ◽  
Gianpaolo Cecere ◽  
Carmine Grasso ◽  
Antonino Memmolo ◽  
Annamaria Vicari

This paper investigated the achievable accuracy from a low-cost RTK (Real Time Kinematic)/PPK (Post Processing Kinematic) GNSS (Global Navigation Satellite Systems) system installed on board a UAV (Unmanned Aerial Vehicle), employing three different types of GNSS Bases (Alloy, RS2 and RING) working in PPK mode. To evaluate the quality of the results, a set of seven GCPs (Ground Control Points) measured by means of the NRTK (Network Real Time Kinematic) technique was used. The outcomes show a RMSE (Root Mean Square Error) of 0.0189 m for an ALLOY Base, 0.0194 m for an RS2 Base and 0.0511 m for RING Base, respectively, on the vertical value of DEMs (Digital Elevation Models) obtained by a photogrammetric process. This indicates that, when changing the Base for the PPK, the solutions are different, but they can still be considered adequate for precision positioning with UAVs, especially when GCPs could be used with some difficulty. Therefore, the integration of a RTK/PPK GNSS module on a UAV allows the reconstruction of a highly detailed and precise DEM without using GCPs and provides the possibility to carry out surveys in inaccessible areas.

2019 ◽  
Vol 8 (4) ◽  
pp. 169 ◽  
Author(s):  
Shady Zahran ◽  
Adel Moussa ◽  
Naser El-Sheimy

The last decade has witnessed a wide spread of small drones in many civil and military applications. With the massive advancement in the manufacture of small and lightweight Inertial Navigation System (INS), navigation in challenging environments became feasible. Navigation of these small drones mainly depends on the integration of Global Navigation Satellite Systems (GNSS) and INS. However, the navigation performance of these small drones deteriorates quickly when the GNSS signals are lost, due to accumulated errors of the low-cost INS that is typically used in these drones. During GNSS signal outages, another aiding sensor is required to bound the drift exhibited by the INS. Before adding any additional sensor on-board the drones, there are some limitations that must be taken into considerations. These limitations include limited availability of power, space, weight, and size. This paper presents a novel unconventional method, to enhance the navigation of autonomous drones in GNSS denied environment, through a new utilization of hall effect sensor to act as flying odometer “Air-Odo” and vehicle dynamic model (VDM) for heading estimation. The proposed approach enhances the navigational solution by estimating the unmanned aerial vehicle (UAV) velocity, and heading and fusing these measurements in the Extended Kalman Filter (EKF) of the integrated system.


2021 ◽  
Vol 10 (8) ◽  
pp. e3410816846
Author(s):  
Fabiane de Fátima Maciel ◽  
Herida dos Reis Silva ◽  
Fábio Luiz Albarici ◽  
Luciano Aparecido Barbosa ◽  
Jorge Luiz Alves Trabanco

Desde a ampliação do sistema rodoviário no Brasil na década de 1930, tem-se um cenário com inúmeras obras viárias em diferentes condições de uso e segurança. Tal fato é preocupante devido à falta de monitoramento adequado em OAEs (Obras de Arte Especiais) e por quem de fato estas estruturas devem ser monitoradas. Estas estruturas estão sujeitas às ações de forças estáticas e dinâmicas, podendo causar deslocamentos e/ou deformações que se caracterizam por sua amplitude, direção e comportamento temporal. Há também processos de deteriorações, sejam por desgaste ao uso ou por solicitações naturais, levando-se ao enfraquecimento da estrutura. A incorporação de métodos de inspeção e monitoramento no comportamento estrutural em OAEs torna-se crescente devido ao alto custo de recuperação destas obras. Contudo, é necessário que haja um plano de monitoramento contínuo ou periódico, de acordo com as grandezas admissíveis de cada estrutura. A tecnologia dos GNSS (Global Navigation Satellite Systems) por meio da metodologia de levantamento RTK (Real Time Kinematic), mostrou-se capaz de oferecer suporte em tempo real no controle de deformações estruturais. Neste contexto, foi desenvolvido o SiGE (Sistema de Gerenciamento Estrutural) para monitoramento e emissão de alertas acerca de eventos previamente determinados pelo operador do sistema. Com a obtenção destes dados em tempo real, é possível avaliar a segurança da estrutura em serviço, monitorar a estrutura de forma contínua e segura e aprimorar projetos futuros com a definição de deslocamentos estruturais máximos.


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.


Author(s):  
A. Masiero ◽  
G. Sofia ◽  
P. Tarolli

Abstract. Most of the high resolution topographic models are currently obtained either by means of Light Detection and Ranging (LiDAR) or photogrammetry: the former is usually preferred for producing very accurate models, whereas the latter is much more frequently used in low cost applications. In particular, the availability of more affordable Unmanned Aerial Vehicles (UAVs) equipped with high resolution cameras led to a dramatic worldwide increase of UAV photogrammetry-based 3D reconstructions. Nevertheless, accurate high resolution photogrammetric reconstructions typically require quite long data processing procedures, which make them less suitable for real-time applications.This work aims at investigating the use of a low cost Time of Flight (ToF) camera, combined with an Ultra-Wide Band (UWB) positioning system, mounted on a drone, in order to enable quasi real time 3D reconstructions of small to mid-size areas, even in locations where Global Navigation Satellite Systems (GNSSs) are not available.The proposed system, tested on a small area on the Italian Alps, provided high resolution mapping results, with an error of few centimeters with respect to a terrestrial close-range photogrammetry survey conducted on the same day.


2022 ◽  
Vol 12 (1) ◽  
pp. 435
Author(s):  
Shulin Zeng ◽  
Cuilin Kuang ◽  
Wenkun Yu

Modern low-cost electronic devices can achieve high precision for global navigation satellite systems (GNSSs) and related applications. Recently, the pseudo-range and carrier phase have been directly obtained from a smartphone to establish a professional-level surveying device. Although promising results have been obtained by linking to an external GNSS antenna, the real-time kinematic (RTK) positioning performance requires further improvement when using the embedded smartphone antenna. We first investigate the observation quality characteristics of the Xiaomi Mi 8 smartphone. The carrier-to-noise-density ratio of L5/E5a signals is below that of L1/E1 signals, and the cycle slip and loss of lock are severe, especially for L5/E5a signals. Therefore, we use an improved stochastic model and ambiguity-resolution strategies to improve the short-baseline RTK positioning accuracy. Experimental results show that the ambiguity fixing rate can reach approximately 90% in 3 h of observations when using the embedded antenna, while the GPS/Galileo/BDS single-frequency combination is more suitable for smartphones. On the other hand, convergence takes 10–30 min, and the RTK positioning accuracy can reach 1 and 2 cm along the horizontal and vertical directions, respectively, if ambiguity is resolved correctly. Moreover, we verify the feasibility of using a mass-produced smartphone for deformation monitoring. Results from a simulated dynamic deformation experiment indicate that a smartphone can recognise deformations as small as 2 cm.


2019 ◽  
Vol 94 ◽  
pp. 01021 ◽  
Author(s):  
Heri Andreas ◽  
Hasanuddin Zainal Abidin ◽  
Dina Anggreni Sarsito ◽  
Dhota Pradipta

For more than two decade, the position on the earth can be precisely determined “real-time” in the order of few centimeters by Real Time Kinematic (RTK) GNSS (Global Navigation Satellite Systems) Method. Nevertheless, few limitations are still recognized such as degradation of accuracy against limited satellite visibilities (e.g. heavy satellite obstructions from forest canopy). It usually takes time to resolve the ambiguities or even in many occasion resulted in failure. Fortunately since recent years to the future seems more satellite systems beside GPS and GLONASS are being launched such as BEIDOU, GALILEO, QZSS, etc. It means that more satellite will be existed above the sky. The term GNSS has changed into Multi GNSS. This Multi GNSS is theoretically adding the value to previous GNSS System like GPS; problems of limited satellite visibilities (e.g. under forest canopy) to the position accuracy perhaps will reduce. Within this paper we try to do study the capabilities of RTK Multi GNSS under forest canopy in Indonesia. We observed by RTK in the forest areas which have canopy of 40 to 90 percent. As conclusion we found improvement in positioning result of even area of very limited satellite visibilities.


2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Christopher H. Roosevelt

AbstractMicrotopographic mapping has a long history in archaeology and has gained prominence recently owing to the proliferation of digital technologies. With such proliferation, it becomes necessary to compare and contrast different approaches based on a common set of criteria. This article compares the implementation and efficiency of two methods of mapping microtopography – ground-based Real-Time Kinematic Global Navigation Satellite System (RTK GNSS) and Unmanned Aerial Vehicle Photogrammetry (UAVP) survey – assessing the pros and cons of each, including those related to data quality. ‘Off-the-shelf’ solutions for methods were used to create the comparative dataset of microtopographic maps of six Middle and Late Bronze Age sites over the course of four seasons between 2007 and 2013 in the study area of the Central Lydia Archaeological Survey in western Turkey. Comparison of results demonstrate that the methods are similar with respect to ease of implementation, cost efficiency, and the (in)significance of data defects, while, unsurprisingly, UAVP survey can be greater than one order of magnitude more labor efficient than RTK GNSS survey and over two orders of magnitude more detailed as measured by data density. The accuracy of both methods is high, within typical error budgets for site-level mapping, and comparable to other recent digital mapping approaches. Accordingly, the results suggest that, given site suitability, UAVP is the more labor and cost-efficient method in the long run, with significant data quality benefits.


Author(s):  
Chen Yu ◽  
Nigel T. Penna ◽  
Zhenhong Li

Real-time centimetre-level precise positioning from Global Navigation Satellite Systems (GNSS) is critical for activities including landslide, glacier and coastal erosion monitoring, flood modelling, precision agriculture, intelligent transport systems, autonomous vehicles and the Internet of Things. This may be achieved via the real-time kinematic (RTK) GNSS approach, which uses a single receiver and a network of continuously operating GNSS reference stations (CORS). However, existing CORS networks have often been established simply by attempting regular spacing or in clusters around cities, with little consideration of weather, climate and topography effects, which influence the GNSS tropospheric delay, a substantial GNSS positional error and which prevents homogeneous RTK accuracy attainment. Here, we develop a framework towards optimizing the design of CORS ground infrastructure, such that tropospheric delay errors reduce to 1.5 mm worth of precipitable water vapour (PWV) globally. We obtain average optimal station spacings of 52 km in local summer and 70 km in local winter, inversely related to the atmospheric PWV variation, with denser networks typically required in the tropics and in mountainous areas. We also consider local CORS network infrastructure case studies, showing how after network modification interpolated PWV errors can be reduced from around 2.7 to 1.4 mm.


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