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EDAS (Egnos Data Access Service) differential GNSS corrections: a reliable free-of-charge alternative for precision farming in Europe

Vázquez J., Lacarra E., Morán J., Sánchez M. A., González A., Bruzual J., Rioja J.

Annual of Navigation

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2019

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No. 26

46--58

EN

EDAS (EGNOS Data Access Service) is the EGNOS internet broadcast service, which provides free of charge access to the data collected and generated by the EGNOS infrastructure. EDAS disseminates over the Internet, both in real time and via an FTP archive, the raw data of the GPS, GLONASS (no commitment on GLONASS data is provided (1)) and EGNOS GEO satellites collected by the receivers located at the EGNOS reference stations, which are mainly distributed over Europe and North Africa. The EDAS services offer several types of GNSS data in various protocols and formats, such as DGNSS corrections. This paper reports on the results of some in-field tests conducted by ESSP and Topcon Agriculture to confirm the suitability of EDAS DGNSS corrections for precision farming in Europe. The European Commission (EC) is the owner of EGNOS system (including EDAS) and has delegated the exploitation of EGNOS to the European GNSS Agency (GSA). EDAS service provision is performed by ESSP, as EGNOS Services Provider, under contract with the GSA, the EGNOS program manager. In the ENC 2018 article “EDAS (EGNOS Data Access Service): Differential GPS corrections performance test with state-of-the-art precision agriculture system”, ESSP and Topcon Agriculture presented the results of the first in-field test conducted in a dynamic and real-life environment in the summer of 2017. The test results indicated that the EDAS DGNSS corrections could enable a reliable pass-to-pass accuracy performance for a wide range of precision agriculture applications and become an attractive solution for cereal farms, when the farm is located in the vicinity of an EGNOS reference station. In particular, Topcon Agriculture acknowledged that the observed performance was sufficient to support the following precision agriculture applications: spraying and spreading of any crop type, tilling and harvesting of cereal. Then, ESSP and Topcon Agriculture engaged in additional testing activities to further characterise the EDAS DGPS performance in different scenarios (i.e. at various European locations and with a variety of distances between the designated farm and the target EGNOS reference station). In each test, multiple runs with the rover tractors have been performed over the reference patterns predefined in the Topcon guidance systems. Data recorded during the tests has been analysed in detail, looking at the key performance indicators (e.g. cross track error and pass-to-pass performance) that characterize the EDAS DGPS performance for precision agriculture applications. Different techniques for the computation of the pass-to-pass accuracy performance have been used, including a procedure to measure live in the field and a post-processing alternative. The diversity of scenarios available allows drawing conclusions on the applicability of EDAS DGPS corrections (in terms of maximum distance from the target EGNOS station) for precision agriculture and also understanding the impact of operationally relevant aspects such as the quality of the mobile internet coverage (highly variable across Europe). The EDAS system and its architecture, the main types of data disseminated through EDAS services and the online information available to the EDAS users are introduced in this paper. In particular, the EDAS Ntrip service is described in detail, since it provides the differential corrections to the GPS and GLONASS satellites at the EGNOS reference stations in RTCM format, which are the basis for the present study. The article also reports on the results of the latest tests, which have been performed using Topcon receivers, vehicles and auto-steering systems. In all cases, two different Topcon guidance systems on board tractors were running simultaneously to assess the EDAS DGPS positioning performance with respect to a the reference provided by a top-performing RTK-based Topcon solution. The objective of this paper is to draw conclusions on the use of EDAS DGPS corrections as a reliable free-of-charge alternative for precision farming in Europe (especially for cereal farms), based on the available performance results from the testing campaign and the feedback from the involved precision agriculture experts.

2

Dynamic probability fields for risk assessment and guidance solutions

Williams Edwin, Jin Yan

Annual of Navigation

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2019

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No. 26

33--45

EN

Standard Guidance, Navigation, and Control (GN&C) systems take state data from a navigation system and create a trajectory that minimizes some a-priori determined cost function. These cost functions are typically time, money, weight, or any general physically realizable quantity. Previous work has been done to show the effectiveness of using risk as the sole objective function. However, this previous work used Poisson distributions and historical estimates to achieve this goal. In this paper we present the situation-risk assessment (SRA) method contained within the intelligent situation assessment and collision avoidance (iSC) platform. The SRA method uses data clustering, and pattern recognition to create a historically based estimate of guidance probabilities. These are then used in data driven, dynamic models to create the future probability fields of the situation. This probability, along with the other agent’s goals and objectives, are then used to create a minimum risk guidance solution in the nautical environment.

3

AIOSAT - Autonomous Indoor & Outdoor Safety Tracking System

Adin Iñigo, Zabalegui Paul, Perez Alejandro, Arrizabalaga Jaione, Goya Jon, Mendizabal Jaizki

Annual of Navigation

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2019

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No. 26

21--32

EN

Even though satellite-based positioning increases rescue workers’ safety and efficiency, signal availability, reliability, and accuracy are often poor during fire operations, due to terrain formation, natural and structural obstacles or even the conditions of the operation. In central Europe, the stakeholders report a strong necessity to complement the location for mixed indoor-outdoor and GNSS blocked scenarios. As such, location information often needs to be augmented. For that, European Global Navigation Satellite System Galileo could help by improving the availability of the satellites with different features. Moreover, a multi-sensored collaborative system could also take advantage of the rescue personnel who are already involved in firefighting and complement the input data for positioning. The Autonomous Indoor & Outdoor Safety Tracking System (AIOSAT) is a multinational project founded through the Horizon 2020 program, with seven partners from Spain, Netherlands and Belgium. It is reaching the first year of progress (out of 3) and the overarching objective of AIOSAT system is to advance beyond the state of the art in tracking rescue workers by creating a high availability and high integrity team positioning and tracking system. On the system level approach, this goal is achieved by fusing the GNSS, EDAS/EGNOS, pedestrian dead reckoning and ultra-wide band ranging information, possibly augmented with map data. The system should be able to work both inside buildings and rural areas, which are the test cases defined by the final users involved in the consortium and the advisory board panel of the project.

4

Measurable realistic image-based 3D mapping

Liu W., Wang J., Wang J. J., Ding W., Almagbile A.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2011

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Vol. 22

297--310

EN

Maps with 3D visual models are becoming a remarkable feature of 3D map services. High-resolution image data is obtained for the construction of 3D visualized models.The3D map not only provides the capabilities of 3D measurements and knowledge mining, but also provides the virtual experienceof places of interest, such as demonstrated in the Google Earth. Applications of 3D maps are expanding into the areas of architecture, property management, and urban environment monitoring. However, the reconstruction of high quality 3D models is time consuming, and requires robust hardware and powerful software to handle the enormous amount of data. This is especially for automatic implementation of 3D models and the representation of complicated surfacesthat still need improvements with in the visualisation techniques. The shortcoming of 3D model-based maps is the limitation of detailed coverage since a user can only view and measure objects that are already modelled in the virtual environment. This paper proposes and demonstrates a 3D map concept that is realistic and image-based, that enables geometric measurements and geo-location services. Additionally, image-based 3D maps provide more detailed information of the real world than 3D model-based maps. The image-based 3D maps use geo-referenced stereo images or panoramic images. The geometric relationships between objects in the images can be resolved from the geometric model of stereo images. The panoramic function makes 3D maps more interactive with users but also creates an interesting immersive circumstance. Actually, unmeasurable image-based 3D maps already exist, such as Google street view, but only provide virtual experiences in terms of photos. The topographic and terrain attributes, such as shapes and heights though are omitted. This paper also discusses the potential for using a low cost land Mobile Mapping System (MMS) to implement realistic image 3D mapping, and evaluates the positioning accuracy that a measureable realistic image-based (MRI) system can produce. The major contribution here is the implementation of measurable images on 3D maps to obtain various measurements from real scenes.

5

Evaluating the performance of mems based inertial navigation sensors for land mobile applications

Kealy A., Retsche G., Grejner-Brzezińska D., Gikas V., Roberts G.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2011

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Vol. 22

237--248

EN

In 2010 a collaborative working group was formed under the professional associations: International Association of Geodesy (IAG WG4.2.5) and International Federation of Surveys (FIG WG5.5). Entitled ubiquitous positioning, this working group aims to harness and develop existing research outputs available internationally in this research domain. Our goal over the next four years is to provide an online resource for academic and industry professionals, who can use these research outputs thereby reducing duplication and facilitating more rapid progress in the development of ubiquitous positioning systems. This paper presents a summary of the research activities and results of the working group to date. In particular, it presents the results of extensive testing to characterize the performance of a range of low-cost MEMS inertial sensors. The test scenarios, data acquisition software, processing tools and results obtained will be fully described and presented. The performance of these sensors in augmenting GNSS positioning is also presented using results obtained from a combination of loosely and tightly coupled Kalman filters. Finally, the future plans for the working group over the next four years and opportunities for wider collaboration will be discussed.

6

Assisting personal positioning in indoor environments using map matching

Attia M., Moussa A., Zhao X., El-Sheimy N.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2011

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Vol. 22

39--49

EN

Personal positioning is facing a huge challenge to maintain a reliable accuracy through all applications. Although in outdoor applications, several mobile navigation devices can provide acceptable positioning accuracy, the situation in indoor environment is not the same. Mobile navigation devices mainly contain a global positioning system (GPS) receiver and an inertial measurement unit (IMU). The main drawback in indoor navigation applications is the unavailability of the GNSS signals, which decreases the possibility of obtaining an accurate absolute position solution, as the inertial system (INS) solution will drift with time in the absence of external updates. Several alternatives were presented lately to update the inertial solution such as using Wi-Fi, UWB, RFID, several self-contained sensors, imaging aiding and spatial information aiding. In order to achieve accurate position solution, with low-cost and usable technique, an integrated mobile navigation system integrating GPS/IMU/Wi-Fi and map-matching was developed. The developed system uses the prior knowledge of the indoor geometrical and topological information, as a threshold for the navigation solution, forcing the provided solution to be mostly on the right track. The geometrical and topological information for the building was used to build the geospatial data model. The use of this model was performed by developing a map matching algorithm which uses the geometrical and topological characteristics of the building to locate the user position on the building map. This algorithm was developed based on the geospatial information of the Engineering building, University of Calgary, where the field test occurred. The map-matching algorithm was evaluated by processing and comparing two separate navigation solutions through the study area, one using only the GPS/IMU/Wi-Fi system, and second solution was assisted with the map-matching algorithm which shows significant enhancement in the position solution for the indoor trajectory.

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A novel single-step procedure for the calibration of the mounting parameters of a multi-camera terrestrial mobile mapping system

Habib A., Kersting A., Bang K., Rau J.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2011

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Vol. 22

173--185

EN

Mobile Mapping Systems (MMS) can be defined as moving platforms which integrates a set of imaging sensors and a position and orientation system (POS) for the collection of geo spatial information. In order to fully explore the potential accuracy of such systems and guarantee accurate multi-sensor integration, a careful system calibration must be carried out. System calibration involves individual sensor calibration as well as the estimation of the inter-sensor geometric relationship. This paper tackles a specific component of the system calibration process of a multi-camera MMS – the estimation of the relative orientation parameters among the cameras, i.e., the inter-camera geometric relationship (lever-arm offsets and boresight angles among the cameras). For that purpose, a novel single step procedure, which is easy to implement and not computationally intensive, will be introduced. The proposed method is implemented in such a way that it can also be used for the estimation of the mounting parameters among the cameras and the IMU body frame, in case of directly georeferenced systems. The performance of the proposed method is evaluated through experimental results using simulated data. A comparative analysis between the proposed single-step and the two-step, which makes use of the traditional bundle adjustment procedure, is demonstrated.

8

A multisensor for electrochemical sequential autonomous automatic measurements

Navratil T., Yosypchuk B., Barek J.

Chemia Analityczna

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2009

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Vol. 54, No. 1

3-17

EN

A newly constructed electrochemical multisensor containing 8 different sensors (5 different solid amalgam electrodes, platinum, gold and glassy carbon electrodes) for analysis of small sample volumes (5-200 μL) was developed. The multisensor was connected to the specially constructed and developed electrochemical multichannel device for sequential autonomous measurements. This device consisted of a computer (PC or notebook), an interface card, and a control box; it was able to control up to 8 sensors (i.e. electrode sets) in a selected sequence, in which each sensor could utilize different detection mode (e.g. DCV, DPV, coulometry, chronopotentiometry, square-wave voltammetry) and operate at different parameters. The analysis of a mixture of ferrocene and nucleic acid bases: adeninę and guanine was used to demonstrate the possibilities of this device.

PL

Opracowano nowy sensor składający się z 8 elektrod, w tym 5 ze stałego amalgamatu i po jednej z platyny, ztota i węgla szklistego. Sensor jest przewidziany do analiz próbek o malej objętości (5-200 μL). Sensor zosta) podłączony do specjalnie skonstruowanego, wielokanałowego urządzenia elektrochemicznego, które umożliwiło sekwencyjne, niezależne pomiary na wszystkich elektrodach. Urządzenie składało się z komputera (PC lub notebook), karty interfejsowej i części kontrolnej. Każdąelektrodę można było użyć w połączeniu z wybraną techniką elektrochemiczną (np. woltamperometria stałoprądowa, woltampe-rometria pulsowa różnicowa, woltamperometria prostokątnej fali, kulometria i chronoam-perometria). W celu zademonstrowania możliwości nowego układu przeprowadzono analizę mieszaniny ferocenu, adenicy i guaniny.