Strobe Pulse Design for Quadrature Multiplexed Binary Offset Carrier Modulation in BeiDou B1C Signal
-
摘要: 第3代北斗卫星导航系统中B1C频点信号将使用正交复用二进制偏移载波调制方式。为了增强北斗卫星导航接收机码跟踪环路的抗多径性能并且解决码跟踪中的模糊跟踪问题,该文针对正交复用二进制偏移载波调制信号QMBOC(6, 1, 4/33)提出一种双闸波码跟踪环路结构。根据理想的目标鉴相函数和二进制偏移载波调制信号自相关函数的特点分别设计出针对BOC(1, 1)和BOC(6, 1)信号的闸波,并在本地码跟踪环路中使用这两种不同的闸波分别与输入信号相关,最后将所得的两个相关函数进行加权合并以用于鉴相过程。计算机仿真结果表明所提方法不仅能够有效消除QMBOC(6, 1, 4/33)信号的模糊跟踪可能性,且能够大幅增强接收机的抗多径性能,其对应多径误差包络面积相比于现有的方法能够减少约33%。
-
关键词:
- 北斗3代 /
- 正交复用二进制偏移载波调制 /
- 抗多径 /
- 模糊跟踪 /
- 闸波
Abstract: The third generation of BeiDou satellite navigation system employs Quadrature Multiplexed Binary Offset Carrier (QMBOC) modulation for B1C signal. In order to improve the anti-multipath performance of code tracking loops and solve the problem of code tracking ambiguity for BeiDou system, a double strobe code tracking loop structure for QMBOC(6, 1, 4/33) modulation is proposed. According to the ideal phase discrimination function and the auto-correlation function of BOC signal, two kinds of strobe pulse are designed for BOC(1, 1) and BOC(6, 1) respectively. Then, these two strobe pulse waveforms are used to correlated with the input signal in the code tracking loop. Finally, these two correlation functions are weighed combined for phase discrimination. The computer simulation results show that the proposed method can not only eliminate the code tracking ambiguity for QMBOC(6, 1, 4/33), but also improve the anti-multipath performance dramatically: the multipath error envelope area is reduced by about 33% compared with the existed method. -
表 1 北斗B1C信号调制方式
通道 载频(MHz) 调制方式 码速率 数据 1575.42 BOC(1,1) 100/s 导频 1575.42 QMBOC(6,1,4/33) 0 表 2 多径抑制性能参数对比
包络面积 包络极值 包络长度 本文方法 0.0024 0.0185 0.1283 W2闸波 0.0025 0.0217 0.5850 窄相关 0.0087 0.0227 0.8408 DST 0.0036 0.0270 0.7575 -
ZITOUNI S, ROUABAH K, CHIKOUCHE D, et al. General analytical models characterizing MBOC modulated signal[J]. Aerospace Science&Technology, 2016, 50: 112–126 doi: 10.1016/j.ast.2015.12.027 张天骐, 江晓磊, 赵军桃, 等. 二进制偏移载波及其衍生信号的通用无模糊捕获算法[J]. 电子与信息学报, 2017, 39(2): 451–458 doi: 10.11999/JEIT160351ZHANG Tianqi, JIANG Xiaolei, ZHAO Juntao, et al. Unambiguous general acquisition for binary offset carrier and its derivative signals[J]. Journal of Electronics&Information Technology, 2017, 39(2): 451–458 doi: 10.11999/JEIT160351 CHAE K, YOO S, SUN Y K, et al. Unambiguous tracking technique based on sub-carrier pulse grouping for TMBOC-modulated signals in GPS[J]. IEEE Access, 2016, 4(1): 7785–7794 doi: 10.1109/ACCESS.2016.2627623 WANG C, CUI X, MA T, et al. Asymmetric dual-band tracking technique for optimal joint processing of BDS B1I and B1C signals[J]. Sensors, 2017, 17(10): 2360–2376 doi: 10.3390/s17102360 LIU F and FENG Y. A main peak extraction method for high-order BOC signals[J]. Journal of Navigation, 2017, 70(5): 1–17 doi: 10.1017/S0373463317000261 LIM D W, CHO D J, CHOI H H, et al. A simple and efficient code discriminator for a MBOC signal tracking[J]. IEEE Communications Letters, 2013, 17(6): 1088–1091 doi: 10.1109/LCOMM.2013.040913.122050 YU J, YANG W, LU W, et al. The tracking accuracy of baseband DLL with AWN[C]. IEEE, International Conference on Signal Processing, Beijing, China, 2013: 1361–1364. doi: 10.1109/ICoSP.2012.6491829. FALLETTI E and MOTELLA B. Combination of squared correlators for multipath mitigation in safety-of-life global navigation satellite systems receivers[J]. IET Radar Sonar&Navigation, 2012, 6(7): 611–619 doi: 10.1049/iet-rsn.2011.0279 WU J and DEMPSTER A G. " BOC-Gated-PRN” a multipath mitigation technique for BOC(n, n) waveforms[J]. IEEE Transactions on Aerospace&Electronic Systems, 2011, 47(2): 1136–1153 doi: 10.1109/TAES.2011.5751248 NUNES F D, SOUSA F M G, and LEITAO J M N. Gating functions for multipath mitigation in GNSS BOC signals[J]. IEEE Transactions on Aerospace&Electronic Systems, 2007, 43(3): 951–964 doi: 10.1109/TAES.2007.4383585 NI S, PANG J, ZHANG K, et al. A novel unambiguous W2 CCRW multipath mitigation algorithm applied to BOC (n, n) signals[C]. China Satellite Navigation Conference (CSNC), Singapore, 2016: 107–113. doi: 10.1007/978-981-10-0937-2_9. LIU Z, LI B, TANG X, et al. Unambiguous s-curve shaping for multipath mitigation for MBOC modulated signals in GNSS[C]. International Conference on Wireless Communications & Signal Processing, Nanjing, China, 2015: 1–5. CHEN H, JIA W, REN J, et al. Unambiguous S-curve shaping technique for multipath mitigation in cosine-BOC signals[J]. IEEE Communications Letters, 2012, 16(11): 1725–1728 doi: 10.1109/LCOMM.2012.091212.121226 SOUSA F M G, NUNES F D, and LEITAO J M N. Code correlation reference waveforms for multipath mitigation in MBOC GNSS receivers[C]. ProcENC-GNSS, Toulouse, France, 2008, 1: 1–10. LIU Z, PANG J, LIU Y, et al. Double strobe technique for unambiguous tracking of TMBOC modulated signal in GPS[J]. IEEE Signal Processing Letters, 2015, 22(12): 2204–2208 doi: 10.1109/LSP.2015.2470240 李文刚, 王屹伟. 基于局部相关函数插值的二进制偏移载波调制信号码相位估计与鉴相方法[J]. 电子与信息学报, 2018, 40(3): 557–564 doi: 10.11999/JEIT170506LI Wengang and WANG Yiwei. Code phase estimate and discrimination method for BOC modulated signal based on partial correlation function interpolation[J]. Journal of Electronics&Information Technology, 2018, 40(3): 557–564 doi: 10.11999/JEIT170506 WU J and DEMPSTER A G. Unambiguous double delta discriminator for sine-phased BOC(n, n)receiver[J]. Journal of Global Positioning Systems, 2013, 10(2): 149–156 doi: 10.5081/jgps.10.2.149 XU C, ZHE L, TANG X, et al. Strobe double phase estimator: A multipath mitigating technique for BOC signal in GNSS based on double phase estimator[J]. International Journal of Satellite Communications&Networking, 2017, 35(3): 249–261 doi: 10.1002/sat.1180 BORIO D. Coherent side-band BOC processing[J]. IET Radar Sonar&Navigation, 2017, 11(10): 1455–1466 doi: 10.1049/iet-rsn.2016.0245 DENG Z, HU E, YIN L, et al. An unambiguous tracking technique for sine-BOC(kn, n) modulated GNSS signals[J]. Wireless Personal Communications, 2017, 11(4): 1–12 doi: 10.1007/s11277-017-5067-5