Multipath mitigation and NLOS detection using vector tracking in urban environments

Li Ta Hsu, Shau Shiun Jan, Paul D. Groves, Nobuaki Kubo

Research output: Journal article publicationJournal articleAcademic researchpeer-review

97 Citations (Scopus)


Multipath interference and non-line-of-sight (NLOS) reception are major error sources when using global navigation satellite systems in urban environments. A promising approach to minimize the effect of multipath interference and aid NLOS detection is vector tracking. Therefore, the objective of this research was to assess vector tracking in a dense urban environment to determine its effect on multipath interference and NLOS reception. Here, a vector delay lock loop is implemented using an adaptive extended Kalman filter. This replaces the individual code-tracking loops and navigation filter, but retains conventional carrier frequency tracking. The positioning and tracking performance of the conventional and vector-tracking implementations with and without a strobe correlator are compared using intermediate frequency signals recorded in the Koto-Ku district of urban canyon Tokyo city environment. Both static and dynamic tests were performed. It is shown that vector tracking reduces the root-mean-square positioning error by about 30 % compared with an equivalent conventional receiver in urban environments and is capable of detecting long-delay NLOS reception for a GPS receiver without any external aiding.

Original languageEnglish
Pages (from-to)249-262
Number of pages14
JournalGPS Solutions
Issue number2
Publication statusPublished - 1 Jan 2015
Externally publishedYes


  • Multipath mitigation
  • Non-line-of-sight (NLOS) detection
  • Strobe correlator
  • Urban canyon
  • Vector delay lock loop (VDLL)
  • Vector tracking

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)


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