Single-channel amplitude-comparison wideband direction finding method with nonuniform time modulation
[Objective]To overcome the problem of the limitation of working bandwidth due to the phase ambiguity caused by the carrier frequency's variation in conventional time-modulated direction finding,a single-channel direction finding method with nonuniform time modulation is proposed in this paper.[Methods]By modulating the signals received by different antenna elements at the same time with nonuni-form periods,the amplitude information can be separately mapped to the corresponding modulated frequency without aliasing.With the amplitude ratio independently extracted from the harmonics,single-channel direc-tion finding for the incident signal can be achieved using the lookup table method.[Results]The feasibility of the proposed method is verified on the basis of the numerical simulation results.Meanwhile,a wideband non-uniform time modulation system available for 2.4 GHz and 5.8 GHz is constructed and its effectiveness demonstrated,with the results showing that the mean of direction finding absolute error is 0.21° and 0.18° re-spectively.[Conclusions]The proposed method can effectively improve the working bandwidth and has such advantages as a simple structure,low cost,low signal processing complexity and wideband direction finding.
time modulationwideband direction findingamplitude comparisonsingle channelnonuni-form modulation
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