A Novel UAV-Assisted Positioning System for GNSS-Denied Environments

Abstract

Global Navigation Satellite Systems (GNSS) are extensively used for location-based services, civil and military applications, precise time reference, atmosphere sensing, and other applications. In surveying and mapping applications, GNSS provides precise three-dimensional positioning all over the globe, day and night, under almost any weather conditions. The visibility of the ground receiver to GNSS satellites constitutes the main driver of accuracy for GNSS positioning. When this visibility is obstructed by buildings, high vegetation, or steep slopes, the accuracy is degraded and alternative techniques have to be assumed. In this study, a novel concept of using an unmanned aerial system (UAS) as an intermediate means for improving the accuracy of ground positioning in GNSS-denied environments is presented. The higher elevation of the UAS provides a clear-sky visibility line towards the GNSS satellites, thus its accuracy is significantly enhanced with respect to the ground GNSS receiver. Thus, the main endeavor is to transfer the order of accuracy of the GNSS on-board the UAS to the ground. The general architecture of the proposed system includes hardware and software components (i.e., camera, gimbal, range finder) for the automation of the procedure. The integration of the coordinate systems for each payload setting is described, while an error budget analysis is carried out to evaluate and identify the system’s critical elements along with the potential of the proposed method.

Cooperative 3D Beamforming for Small-Cell and Cell-Free 6G Systems

“…Finally, the average capacity per unit bandwidth can be found by integrating (11) over all possible user and interference locations (u) and is formulated as:…”

“…When we have k s ≫ 1 and c σ ≪ k 2 s , the absolute value of arguments in the exponential integral Ei of (10) is large. Hence, the approximation Ei(z) ≈ e z z [67] can be used to simplify it, which results in (11). APPENDIX C Lemma 1.…”

“…These UAVs may play the role of both user equipment (UE) and of arial base stations (BS). These air-born UEs coexist with terrestrial ground users and are often termed as cellular-connected UAVs, which have been harnessed in applications such as remote sensing [10], [11], package delivery [12], surveillance [13] etc. A direct consequence of this new paradigm is that the UEs and BSs are going to co-exist in 3D space, where many of these have to engage in simultaneous communications.…”

Cooperative 3D Beamforming for Small-Cell and Cell-Free 6G Systems

“…These UAVs may play the role of both user equipment (UE) and of aerial base stations (BS). These air-born UEs coexist with terrestrial ground users and are often termed as cellular-connected UAVs, which have been harnessed in applications such as remote sensing [10], [11], package delivery [12], surveillance [13] etc. A direct consequence of this new paradigm is that the UEs and BSs are going to co-exist in 3D space, where many of these have to engage in simultaneous communications.…”