Interference and multipath mitigation utilising a two‐stage beamformer for global navigation satellite systems applications. Issue 1 (1st January 2013)

• Record Type: Journal Article
• Authors: Daneshmand, Saeed; Broumandan, Ali; Nielsen, John; Lachapelle, Gérard
• Is Part Of: IET radar, sonar & navigation. Volume 7:Issue 1(2013)
• Page Start: 55
• Page End: 66
• Publication Date: 2013-01-01
• Subjects: antenna arrays -- array signal processing -- correlation methods -- matrix algebra -- multipath channels -- optimisation -- satellite navigation -- signal denoising; two‐stage beamformer -- global navigation satellite systems applications -- GNSS -- location‐based services -- time‐frequency interference suppression methods -- wideband interference signals -- broadband interference signal mitigation -- narrowband interference signal mitigation -- antenna elements -- antenna arrays -- coherent multipath components -- signal cancellation phenomenon -- temporal correlation matrix rank deficiency -- interference subspace -- optimisation problem -- minimum power distortionless response beamformer -- minimum difference output power method -- multipath mitigation; Signal processing -- Periodicals; Radar -- Periodicals; Sonar -- Periodicals; Electronics in navigation -- Periodicals; Navigation -- Periodicals; 621.3848
• DOI: 10.1049/iet-rsn.2012.0027
• Languages: English
• ISSNs: 1751-8784

Abstract

Abstract : The performance of location‐based services provided by global navigation satellite systems is compromised by interference and multipath propagations. Although time/frequency interference suppression methods have been widely studied in the literature, they fail to cope with wideband interference signals. Instead, techniques utilising several antenna elements can be employed to mitigate both narrowband and broadband interference signals. However, the performance of beamforming techniques utilising antenna arrays severely degrades in dealing with correlated and coherent multipath components which cause signal cancellation phenomenon and temporal correlation matrix rank deficiency. This study proposes a two‐stage beamformer to jointly deal with interference and multipath signals. In the first stage, before the despreading process, by applying the subspace method, the interference subspace is estimated and used as a constraint for the optimisation problem in the next stage. In the second stage, a modified version of the minimum power distortionless response beamformer employing several overlapping sub‐arrays called the minimum difference output power method is utilised to mitigate the correlated multipath components. The proposed beamformer can deal with the signal cancellation phenomenon and temporal correlation matrix rank deficiency. Several simulation examples and a real data test are provided to illustrate the effectiveness of the proposed beamformer. Results show that the proposed method is able to put deep nulls in the direction of the narrowband and wideband interference signals, and significantly reduces the multipath‐induced time of the arrival error.