Performance assessment of GNSS diffraction models in urban areas

Abstract

The GNSS performance is significantly degraded in urban canyons because of the signal interferences caused by buildings. Besides the multipath and non‐line‐of‐sight (NLOS) receptions, the diffraction effect frequently occurs in urban canyons, which will severely attenuate the signal strength when the satellite line‐of‐sight (LOS) transmitting path is close to the building edge. It is essential to evaluate the performance of current diffraction models for GNSS before applying mitigation. The detailed steps of applying the knife‐edge model and the uniform geometrical theory of diffraction (UTD) model on GNSS are given, including the C/N0 and pseudorange simulation of the diffracted signal. The performances of both models are assessed using real data from two typical urban scenarios. The result shows the UTD can adequately model the GNSS diffraction effect even in a complicated urban area. Compared with the knife‐edge model, the UTD achieves better modeling accuracy, whereas it requires higher computational loads.

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“…Diffraction and reflection delays are different, and different strategies should be applied separately to these effects (Zhang & Hsu, 2021). This diffraction path of G08 passes through the narrow gap between two buildings, and multiple reflections may occur on these two surfaces.…”

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Predicting C/N0 as a Key Parameter for Network RTK Integrity Prediction in Urban Environments

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