Robustness of High Accuracy GNSS-based Positioning using GNSS Reference Stations in Urban Environments

2020 ◽  
Author(s):  
Daniel H. Olesen ◽  
Anna B.O. Jensen ◽  
Søren S. Larsen ◽  
Samuel Lukac
Keyword(s):  
High Accuracy ◽  
Urban Environments

Enabling High Accuracy Dynamic Applications in Urban Environments Using PPP and RTK on Android Multi-Frequency and Multi-GNSS Smartphones

2019 ◽  
Author(s):  
Marco Fortunato ◽  
Joshua Critchley-Marrows ◽  
Malgorzata Siutkowska ◽  
Maria Loredana Ivanovici ◽  
Elisa Benedetti ◽  
...  
Keyword(s):  
High Accuracy ◽  
Urban Environments

Low Cost, High Accuracy Positioning In Urban Environments

2006 ◽  
Vol 59 (3) ◽  
pp. 365-379 ◽  
Author(s):  
Chris Hide ◽  
Terry Moore ◽  
Chris Hill ◽  
David Park
Keyword(s):  
Urban Environment ◽  
Real Time ◽  
Low Cost ◽  
High Accuracy ◽  
Urban Environments ◽  
Reference Trajectory ◽  
Differential Gps ◽  
Positioning Accuracy ◽  
Gps Receivers ◽  
Better Than

It is well known that GPS measurements are regularly obstructed in urban environments. Positioning accuracy in such environments is significantly degraded and in many areas, it is not possible to obtain a GPS position fix at all. There are currently two methods that can be used to improve availability in the urban environment. Firstly, GPS receivers can be augmented with dead reckoning sensors such as an INS. Alternatively, High Sensitivity GPS (HSGPS) receivers can be used which are able to acquire and track very weak signals. This paper assesses the performance obtained from a GPS and low cost INS integrated system and a HSGPS receiver in an urban environment in Nottingham, UK. The navigation systems are compared to a high accuracy integrated GPS/INS system which is used to provide a reference trajectory. It is demonstrated that the differential GPS and low cost INS system can provide horizontal positioning accuracy of better than 2·5 m RMS in real-time, and better than 1 m RMS in post-processing, whereas the non-differential HSGPS receiver provides a real-time performance of 5 m RMS. These results were obtained in an environment where, with conventional GPS receivers, a position solution is only available 48·4% of the time. Operational considerations such as initial alignment of the GPS and low cost INS are also discussed when comparing the two systems for urban positioning applications.

scholarly journals Background and Recent Advances in the Locata Terrestrial Positioning and Timing Technology

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1821 ◽  
Author(s):  
Chris Rizos ◽  
Ling Yang
Keyword(s):  
Literature Review ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
High Accuracy ◽  
Urban Environments ◽  
Navigation Satellite ◽  
Positioning Systems ◽  
Comprehensive Literature Review ◽  
The World ◽  
Global Navigation Satellite

Global Navigation Satellite System (GNSS) is the most widely used Positioning, Navigation, and Timing (PNT) technology in the world today, but it suffers some major constraints. Locata is a terrestrial PNT technology that can be considered as a type of localised “constellation”, which is able to provide high-accuracy PNT coverage where GNSS cannot be used. This paper presents a comprehensive literature review of the Locata technology and its applications. It seeks to answer questions, such as: (1) What is Locata and how does it work? (2) What makes Locata unique compared with other terrestrial positioning systems? (3) How has Locata been used in different applications for accurate PNT? (4) What are the current challenging issues that may restrict its further adoption for custom-grade navigation in urban environments?

scholarly journals Implementation of a Lagrangian Stochastic Particle Trajectory Model (LaStTraM) to Simulate Concentration and Flux Footprints Using the Microclimate Model ENVI-Met

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 977
Author(s):  
Helge Simon ◽  
Jannik Heusinger ◽  
Tim Sinsel ◽  
Stephan Weber ◽  
Michael Bruse
Keyword(s):  
Particle Trajectory ◽  
High Accuracy ◽  
Complex Model ◽  
Urban Environments ◽  
Flux Footprint ◽  
Trajectory Model ◽  
Flux Measurements ◽  
Particle Trajectory Model ◽  
Flux Footprints ◽  
Stochastic Particle

The number of studies evaluating flux or concentration footprints has grown considerably in recent years. These footprints are vital to understand surface–atmosphere flux measurements, for example by eddy covariance. The newly developed backwards trajectory model LaStTraM (Lagrangian Stochastic Trajectory Model) is a post-processing tool, which uses simulation results of the holistic 3D microclimate model ENVI-met as input. The probability distribution of the particles is calculated using the Lagrangian Stochastic method. Combining LaStTraM with ENVI-met should allow us to simulate flux and concentration footprints in complex urban environments. Applications and evaluations were conducted through a comparison with the commonly used 2D models Kormann Meixner and Flux Footprint Predictions in two different meteorological cases (stable, unstable) and in three different detector heights. LaStTraM is capable of reproducing the results of the commonly used 2D models with high accuracy. In addition to the comparison with common footprint models, studies with a simple heterogeneous and a realistic, more complex model domain are presented. All examples show plausible results, thus demonstrating LaStTraM’s potential for the reliable calculation of footprints in homogeneous and heterogenous areas.

scholarly journals Methodology for Simulating 5G and GNSS High-Accuracy Positioning

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3220 ◽  
Author(s):  
José del Peral-Rosado ◽  
Jani Saloranta ◽  
Giuseppe Destino ◽  
José López-Salcedo ◽  
Gonzalo Seco-Granados
Keyword(s):  
High Accuracy ◽  
Urban Environments ◽  
Global Navigation Satellite Systems ◽  
Base Stations ◽  
Line Of Sight ◽  
Millimetre Wave ◽  
Localization Accuracy ◽  
Satellite Systems ◽  
Hybrid Positioning ◽  
Global Navigation Satellite

This paper focuses on the exploitation of fifth generation (5G) centimetre-wave (cmWave) and millimetre-wave (mmWave) transmissions for high-accuracy positioning, in order to complement the availability of Global Navigation Satellite Systems (GNSS) in harsh environments, such as urban canyons. Our goal is to present a representative methodology to simulate and assess their hybrid positioning capabilities over outdoor urban, suburban and rural scenarios. A novel scenario definition is proposed to integrate the network density of 5G deployments with the visibility masks of GNSS satellites, which helps to generate correlated scenarios of both technologies. Then, a generic and representative modeling of the 5G and GNSS observables is presented for snapshot positioning, which is suitable for standard protocols. The simulations results indicate that GNSS drives the achievable accuracy of its hybridisation with 5G cmWave, because non-line-of-sight (NLoS) conditions can limit the cmWave localization accuracy to around 20 m. The 5G performance is significantly improved with the use of mmWave positioning with dominant line-of-sight (LoS) conditions, which can even achieve sub-meter localization with one or more base stations. Therefore, these results show that NLoS conditions need to be weighted in 5G localization, in order to complement and outperform GNSS positioning over urban environments.

scholarly journals High-Accuracy Positioning in Urban Environments Using Single-Frequency Multi-GNSS RTK/MEMS-IMU Integration

2018 ◽  
Vol 10 (2) ◽  
pp. 205 ◽  
Author(s):  
Tuan Li ◽  
Hongping Zhang ◽  
Zhouzheng Gao ◽  
Qijin Chen ◽  
Xiaoji Niu
Keyword(s):  
High Accuracy ◽  
Urban Environments ◽  
Single Frequency ◽  
Mems Imu

A New 1,000 kV Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 260-261
Author(s):  
M. Nishigaki ◽  
S. Katagiri ◽  
H. Kimura ◽  
B. Tadano
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
Basic Research ◽  
Chromatic Aberration ◽  
High Accuracy ◽  
Biological Specimen ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron

The high voltage electron microscope has many advantageous features in comparison with the ordinary electron microscope. They are a higher penetrating efficiency of the electron, low chromatic aberration, high accuracy of the selected area diffraction and so on. Thus, the high voltage electron microscope becomes an indispensable instrument for the metallurgical, polymer and biological specimen studies. The application of the instrument involves today not only basic research but routine survey in the various fields. Particularly for the latter purpose, the performance, maintenance and reliability of the microscope should be same as those of commercial ones. The authors completed a 500 kV electron microscope in 1964 and a 1,000 kV one in 1966 taking these points into consideration. The construction of our 1,000 kV electron microscope is described below.

The influence of natural and urban environments on attentional processing of emotional stimuli

2014 ◽  
Author(s):  
Chrono Nu ◽  
Katie Mullin ◽  
Hailey Edwards ◽  
Kailey Kornhauser ◽  
Russell Costa ◽  
...  
Keyword(s):  
Urban Environments ◽  
Emotional Stimuli ◽  
Attentional Processing

Minimetrò in Perugia as leverage for urban regeneration

TERRITORIO ◽  
2020 ◽  
pp. 148-163
Author(s):  
Luca Fondacci
Keyword(s):  
Urban Regeneration ◽  
Urban Environments ◽  
Low Carbon ◽  
Sustainable Mobility ◽  
Field Surveys ◽  
Peripheral Area ◽  
Alternative Means ◽  
Considerable Impact ◽  
The City ◽  
Historical Centre

In the 1970s, the fragile historical centre of the city of Perugia was a key area where the binomial of sustainable mobility and urban regeneration was developed and applied. At the turn of the xxi century, the low carbon automatic people-mover Minimetrò broadened that application from the city's historical centre to the outskirts, promoting the enhancement of several urban environments. This paper is the outcome of an investigation of original sources, field surveys and direct interviews, which addresses the Minimetrò as the backbone of a wide regeneration process which has had a considerable impact on the economic development of a peripheral area of the city which was previously devoid of any clear urban sense. The conclusion proposes some solutions to improve the nature of the Minimetrò as an experimental alternative means of transport.

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