A generalized approach for narrowband interference （NBI） suppression in direct sequence spread spectrum （DSSS） communication systems using adaptive infinite impulse response （IIR） filter is presented. The excisi...A generalized approach for narrowband interference （NBI） suppression in direct sequence spread spectrum （DSSS） communication systems using adaptive infinite impulse response （IIR） filter is presented. The excision filter coefficients depend on both the jammer power and its instantaneous frequency. The dependency of the filter construction on the jammer power is significant as it allows optimal tradeoff between interference removal and signal distortion by maximizing the receiver signal to noise ratio improvement（SNRI）. Instead of traditional adaptive line enhancer （ALE） estimator, a preferable NBI estimator-Fourier interpolation estimator （FIE） is proposed. Closed-form expressions of the SNR improvement and theoretical bit error rate （BER） based on the assumption that the output of the correlator is Gaussian distributed are both derived. Performance results obtained by numerical simulation are also presented and compared with theoretical results.展开更多
The NAVSTAR Global Positioning System （GPS）, a networked system providing three-dimenslon user position and timing, is widely used during the past ten years. However, interferences to GPS introduce great dangers to ...The NAVSTAR Global Positioning System （GPS）, a networked system providing three-dimenslon user position and timing, is widely used during the past ten years. However, interferences to GPS introduce great dangers to GPS users. This paper gives an assessment of interferences to the GPS positioning signal. The work is mainly concentrated on effects of wide band interferences. Effects of traditional interferences such as continuous wave （CW）, as well as broadband noise and pulse interference are studied. Furthermorre, according to the GPS＇ s signal characteristics, another kind of wideband interferences, named m sequence interference in this paper, is also studied. Simulation results show that m sequence interference is the most harmful to GPS C/A code if special m sequence is adopted and thus special countermeasures should be used to eliminate this effect.展开更多
基金Sponsored by the Beijing Municipal Natural Science Foundation(4052024)
文摘A generalized approach for narrowband interference （NBI） suppression in direct sequence spread spectrum （DSSS） communication systems using adaptive infinite impulse response （IIR） filter is presented. The excision filter coefficients depend on both the jammer power and its instantaneous frequency. The dependency of the filter construction on the jammer power is significant as it allows optimal tradeoff between interference removal and signal distortion by maximizing the receiver signal to noise ratio improvement（SNRI）. Instead of traditional adaptive line enhancer （ALE） estimator, a preferable NBI estimator-Fourier interpolation estimator （FIE） is proposed. Closed-form expressions of the SNR improvement and theoretical bit error rate （BER） based on the assumption that the output of the correlator is Gaussian distributed are both derived. Performance results obtained by numerical simulation are also presented and compared with theoretical results.
基金Sponsored by Foundation of Harbin Institute of Technology(Grant No. HIT.02.07).
文摘The NAVSTAR Global Positioning System （GPS）, a networked system providing three-dimenslon user position and timing, is widely used during the past ten years. However, interferences to GPS introduce great dangers to GPS users. This paper gives an assessment of interferences to the GPS positioning signal. The work is mainly concentrated on effects of wide band interferences. Effects of traditional interferences such as continuous wave （CW）, as well as broadband noise and pulse interference are studied. Furthermorre, according to the GPS＇ s signal characteristics, another kind of wideband interferences, named m sequence interference in this paper, is also studied. Simulation results show that m sequence interference is the most harmful to GPS C/A code if special m sequence is adopted and thus special countermeasures should be used to eliminate this effect.
