Improved anti‐jamming scheme for direct‐sequence spread‐spectrum receivers

Abstract

An anti-jamming scheme on the base band instead of the intermediate frequency (IF) is proposed to improve the anti-jamming capability of direct-sequence spread-spectrum (DSSS) receivers. For timefrequency domain technology, both the residual jamming energy and the unexpected loss of signal energy resulting from inaccurate jamming rejection would reduce the capability of signal acquisition. The scheme of detecting jamming by FFT and rejecting jamming by notch filters on the base band is exploited to improve the accuracy of jamming rejection. Monte Carlo simulation results show that the proposed scheme could enhance the anti-jamming capability of DSSS receivers.

Antijamming Improvement for Frequency Hopping Using Noise-Jammer Power Estimator

“…Military wireless communications need to mitigate jammers to attain reliability. To reduce jamming, several antijam techniques, such as frequency-hopping spread spectrum (FHSS) and direct-sequence spread spectrum (DSSS), were researched [3][4][5][6][7][8][9][10][11][12][13][14][15]. When jammer power is large, the FHSS is known to be more effective [16], but BER degradation remains.…”

An architecture design for anti-jamming circuit with low power and low area cost in high-precision GNSS receiver chip

“…However, its disadvantages are also obvious for VLSI design [14,15], which requires high area cost and dynamic power for the FFT and IFFT circuit. The time domain solution mainly utilizes the correlation of narrowband jamming to predict the frequency of the jamming signals in the current signal, and uses the adaptive notch filter (ANF) to suppress the jamming signals [16,17,18,19,20]. Although the hardware resources of the time domain solution have the lowest requirements compared with other solutions, if there are multiple jamming signals in the GNSS signal, the jamming signals can only be detected and eliminated serially.…”

Hybrid anti‐jamming approach for kinematic global positioning system receivers

“…In most GPS anti-jamming applications, only the first effect is considered and hence only a pre-correlation mitigation block is designed to overcome jamming attacks. Adaptive time filtering [7,8], frequency filtering [9][10][11][12], time-frequency (t-f) filtering [13][14][15][16][17][18][19], and spatial filtering [20,21] methods are the most common pre-correlation mitigation techniques in GPS receivers. The first three groups are suitable for narrowband jamming mitigation and the fourth group is appropriate for both narrowband and wideband jamming mitigation [15].…”

“…Adaptive filtering methods are simple and thus they are suitable for real-time applications. However, they need primary information about jamming signal [7][8][9][10][11][12]. In [17], a waveletpackets transform (WPT)-based anti-jamming system is proposed, which can detect and mitigate narrowband jamming.…”

“…The pre-correlation block is employed to ensure that at least four satellites can be acquired in jamming environments. As the most adaptive filtering methods need primary information about jamming signal [7][8][9][10] and spatial filtering methods impose extra hardware to the system (and are also computationally complex) [20,21], t-f-based mitigation methods are more suitable for employing in the pre-correlation block. Hence, the pre-correlation block employs short-time Fourier transform (STFT) to detect and mitigate narrowband jamming.…”