Vector Delay Lock Loop Research Articles

Anti‐jamming scheme for GPS receiver with vector tracking loop and blind beamformer

A novel scheme with an antenna array and a vector delay lock loop (VDLL) is proposed for improving the anti-jamming capability of the global positioning system (GPS) receiver. The VDLL is used to supply reference information relying on the unique structure of the coarse/acquisition code for blind beamformers. A spectral self-coherent restoral with a sparse constraint algorithm is presented to suppress interference and preserve the satellite signal without the direction of arrival of the satellite signal. Simulation results show that the proposed method can not only successfully suppress interference but also ensure the reliability of the VDLL in the presence of interference.

Multipath mitigation and NLOS detection using vector tracking in urban environments

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 .