Introduction Conclusions References Tables Figures Back Close Abstract Introduction Conclusions References Tables Figures Back Close Abstract The Martilli's urban parameterization scheme is improved and implemented in a mesoscale model in order to take into account the typical effects of a real city on the air temperature near the ground and on the surface exchange fluxes. The mesoscale model i...

The current global navigation satellite systems (GNSS) receiver cannot calculate satisfactory positioning results in urban environment due to multipath and non-line-of-sight (NLOS) effects. The research team of The University of Tokyo developed a particle filter based positioning method using a basic 3-dimension city building to rectify the positioning result of commercial GPS single frequency ...

his investigation was carried out to reveal the impact of solar radiation on wind flow structure and pollutant dispersion in an urban street canyon of aspect ratio of one using the computational fluid dynamic (cfd) technique. the simulation results (velocity and concentration data) show that heating from building wall surfaces and ground lead to strong buoyancy forces as the air is heated by th...

Martilli’s urban parameterization scheme is improved and implemented in a mesoscale model in order to take into account the typical effects of a real city on the air temperature near the ground and on the surface exchange fluxes. The mesoscale model is run on a single column using atmospheric data and radiation recorded above roof level as forcing. Here, the authors validate Martilli’s urban bo...

The GPS signal is subject to a variety of potential degradations, such as path loss (e.g., foliated or indoor environments), multipath (e.g., urban canyon or inbuilding), and interference (intentional or unintentional). There are many applications, both commercial and military, where a group of GPS users may operate together in a denied or degraded GPS environment. Using the traditional GPS rec...

RTK GPS has become a global utility in engineering survey activities. RTK GPS offers an efficient means of providing near instantaneous positions by employing differential GPS positioning whereby users can obtain sub-centimetre/millimetre level position in real time. In RTK GPS all algorithms using code information only are limited to range accuracy of about 0.5-1.0 metres due to code noise. Ho...

This paper presents a method to perform global localization in urban environments using segment-based maps in combination with particle filters. In the proposed approach the likelihood function is generated as a grid, derived from segment-based maps. The scheme can efficiently assign weights to the particles in real time, with minimum memory requirements and without any additional pre-filtering...

In this paper, detailed numerical simulations of sound propagation in an urban environment are presented. The focus is on propagation from a “source canyon” to a distant “receiver canyon”. Such numerical simulations have to take into account multiple reflections, both specular and diffuse, multiple diffractions, the presence of different building materials, and also the interaction with a movin...

ADREA-HF, which is a Computational Fluid Dynamics (CFD) code, is utilised in order to numerically study the flow and concentration fields within a street-canyon area. The selected site is Runeberg Str., a typical urban street canyon with an aspect ratio of approximately 1:1 in Helsinki, Finland. The ADREA-HF model is a transient, non-hydrostatic, dense transport code, especially developed for d...

Different revolutionary applications, like the unmanned autonomous systems, require a highly precise positioning with centimetre-level accuracies. And real-time kinematic (RTK) GNSS stands chance to these potential applications. RTK can provide in open-sky or suburban environments. However, performance is limited deep urban canyon severe multipath and cycle slip effects. The measurements noise ...