Toward Reliable UAV-Enabled Positioning in Mountainous Environments: System Design and Preliminary Results

Abstract

Reliable positioning services are extremely important for users in mountainous environments. However, in such environments, the service reliability of conventional wireless positioning technologies is often disappointing due to frequent nonline-of-sight (NLoS) propagation and poor geometry of available anchor nodes. Hence, we propose a unmanned aerial vehicle (UAV)-enabled positioning system that utilizes UAV's mobility to overcome the above challenges. In this article, we first analyze and model the major causes of service failures in the proposed system. In particular, a geometry-based NLoS probability model is established based on the digital elevation models (DEM) of realistic terrain for reliability analysis. Subsequently, we propose a reliability prediction method and derive the corresponding metric to evaluate the system's ability to provide reliable positioning services. Moreover, we also develop a voting-based method for the further enhancement of service reliability. Monte-Carlo simulations show that in mountainous environments, the proposed reliability prediction method could achieve a prediction accuracy that is at least 36.8% higher than that of the existing technique. In addition, in the experiments conducted in two typical valley scenarios, the proposed reliability enhancement method improves the service reliability of the proposed system by 23% and 29%, respectively. These numerical results demonstrate the strong potential of the proposed system and methods for reliable positioning.

Management of Positioning Functions in Cellular Networks for Time-Sensitive Transportation Applications

“…Therefore, in order to provide guidance for practical ITS applications and analyze the general performance of the proposed muting management in cellular networks, shown in Fig. 8 T is regarded as the "BS- 7 The solid dot in each PRS correlation function represents the correlation peak, which may not be the position corresponding to the true time delay since random noise and interference is also present. adjacent area".…”

“…The widely used Global Navigation Satellite Systems (GNSS) offers an affordable and easily accessible position information as an add-on service to a user equipment (UE). However, satellite-based positioning systems suffer a severe deterioration due to frequent blockage and degradation in dense urban environments [6], [7]. To make matters worse, GNSS jammers and cycle slips in the real time kinematic (RTK) approaches would also inevitably lead to undesirable system outages [8], [9].…”

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“…Unlike satellites and terrestrial BSs, unmanned aerial vehicles (UAVs) can be controlled to fly to places where they can establish line-of-sight (LoS) links with ground users [7]. In addition, by considering the UAV-user layout in the deployment of UAVs, the problem of poor geometry can also be addressed [8]. Because of the aforementioned advantages of UAVs, UAV-enabled positioning that uses UAVs as aerial anchor nodes has been envisioned as a promising solution for positioning in challenging environments [9], [10].…”

“…Compared with TDoA and other positioning techniques used in terrestrial networks, TWR technique can ease the constraint of clock synchronization through the exchange of messages, making it suitable for mobile anchor nodes like UAVs [32]. As derived in [8], the relative range measurement corresponding to the j-th UAV-A and i-th UAV-B can be written as…”

Bearings only passive location of UAV in formation flight based on computer simulation

“…Therefore, it has become a research hotspot of current target tracking. The current bearings only passive location of UAV is based on this background for bearing tracking [3].…”