MBOC(6,1,4/33) 신호의 다중경로 영향 완화를 위한 새로운 Strobe 펄스 설계

Abstract

In this paper, we propose a novel strobe pulse to mitigate the multipath effect of MBOC (6,1,4/33) signal and analyze its performance. By additionally modulating a passband Direct Sequence/Spread Spectrum (DS/SS) signal with a Binary Offset Carrier (BOC) sub-carrier, the signal band can be moved to a desired band, thereby increasing frequency efficiency. In addition, the correlation characteristics of the correct code synchronization point are improved, so that the multipath effect can be reduced to compare with the existing Binary Phase Shift Keying (BPSK) modulated signal. However, the multipath effect is still one of the major performance limitations of the Global Navigation Satellite Systems (GNSSs). A conventional scheme to mitigate multipath effects of GNSS is the Strobe pulse technique. In this paper, we design a new strobe pulse that can effectively mitigate the multipath effects of MBOC (6,1,4/33) signals, and multipath mitigation in the 2-Ray model, a representative channel environment to assess the multipath mitigation performance by computer-based simulation. In order to compare the performance of the proposed new strobe pulse, the W2 pulse scheme with similar implementation complexity is considered. The W2 pulse technique is the one of the Strobe pulse technique for BOC signal. Based on the output of the discriminator in multipath free environment, the pull-in range of the W2 pulse technique is about 0.2 chips, whereas the proposed scheme is about 0.6 chips, which is about 3 times wider. And the false-lock point of the proposed scheme is less than about 20% to compare the W2 scheme. In the same environment, the multipath error envelope of the W2 and the proposed schemes is shown, and both techniques are affected only by the closed-in multipath signal. Among them, the proposed scheme has significantly lower multipath errors due to the closed-in multipath signal compared to the W2 technique, and the maximum value of the proposed scheme based on the running average of the multipath errors is about 32% compared to the W2 scheme.