New Modified Urban Canyon Models for Satellite Signal Propagation Prediction

Abstract

The effects of high-rise buildings on satellite propagation in the vicinity of urban canyons are investigated. A comparison between a conventional canyon model and the two modified canyon models, which take into account the presence of high-rise buildings, is presented for both narrow-band and wideband signal cases. The narrow band is developed using ray tracing (RT) and includes the direct wave, the specular reflection from building walls and ground, and the diffracted waves. In addition, multiple shadow boundaries are defined and used to carry out the uniform theory of diffraction calculations. The incident shadow boundary is the dominant boundary and is used to determine the line-of-sight region for all cases, while wall and ground reflection shadow boundaries are used to obtain higher precision due to multiple reflections. The wideband model is developed by applying a channel transfer function to the data obtained from the RT method. The proposed models are used to predict the received signal in a realistic urban environment from satellites. The models are applicable to any satellite link application, such as global navigation satellite systems, low Earth-orbiting, and high-altitude platform systems, and the results are obtained for a satellite transmitting two linearly polarized signals at a frequency of 1.625 GHz. It is found that the presence of highrise buildings next to a street canyon can significantly alter the visibility of satellites, which, in turn, lead to an increase in path loss. Consequently, ignoring high-rise buildings in the proximity of a street canyon can lead to a path loss difference of as much as 30 dB. INDEX TERMS Street canyon, conventional canyon model (CCM), non-line of sight (NLOS), ray tracing (RT), uniform theory of diffraction (UTD).

Performance Analysis of Urban Satellite-Terrestrial Networks with 3D Blockage Effects: A Stochastic Geometry Approach

“…Limited research has been conducted on satellite communication that considers explicitly the dense nature of urban areas [25]- [28]. The authors in [25], [26] present deterministic propagation models for conventional and modified urban canyons in 2D, confined to small-scale satellite networks and not appropriate for statistical analyses involving probabilistic methods. The work in [27] presents a satellite-to-ground pathloss model incorporating environment-specific properties for dense environments.…”

Comparing Positioning Performance of LEO Mega-Constellations and GNSS in Urban Canyons

“…In the article [10], the author introduces modified propagation models tailored for urban canyons, which require knowledge of satellite signal properties to estimate path losses within the canyons. Another approach involves the use of the City Geography Markup Language (CityGML) model to represent urban environments, which is subsequently converted into a STereoLithography (STL) surface model [11].…”

Link Budget Analysis for LEO Satellites Based on the Statistics of the Elevation Angle

“…On the other hand, the minimum link length occurs close to the maximum elevation angle, θ max , which ideally coincides with the ES zenith, and with the minimum value of r S,E . With obstructed line of sight conditions, the best and worst-case elevation angle for a particular ES location can be determined by several methods, including geometrical-based approximations using data of the obstacles height and position as in [28]. Another approach based on digital hemispherical photographs has been utilized by [29] and more recently, by [30] and [31], among others, to extract the elevation angle conditions of a particular location.…”