RT Journal Article SR Electronic T1 Performance assessment of GNSS diffraction models in urban areas JF NAVIGATION: Journal of the Institute of Navigation JO NAVIGATION FD Institute of Navigation SP 369 OP 389 DO 10.1002/navi.417 VO 68 IS 2 A1 Guohao Zhang A1 Li-Ta Hsu YR 2021 UL https://navi.ion.org/content/68/2/369.abstract AB The GNSS performance is significantly degraded in urban canyons because of the signal interferences caused by buildings. Besides the multipath and nonline-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 πΆβˆ•π‘0 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.