共查询到14条相似文献,搜索用时 140 毫秒
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CCRW技术在MBOC调制信号下多径抑制性能 总被引:1,自引:0,他引:1
由于频谱与二相移键控(BPSK)信号有较好的分离度且具有良好的跟踪性能,多元二进制偏置载波(MBOC)调制为GPS现代化和Galileo系统所采用,其多径抑制技术也成为研究热点。选取了四种典型的码相关参考波形(CCRW)技术,研究了其应用于MBOC信号时的多径抑制性能,并与BPSK和BOC(1,1)调制下的多径抑制性能进行了比较。通过仿真可知,在同等条件下,W2、W3、w4CCRW技术在时系多元二进制偏置载波(TMBOC)调制下多径抑制性能最差,在二进制偏置载波(CBOC)调制下性能最优,但三种方法均优于W1CCRW. 相似文献
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采用窄相关技术和双△相关技术,对BPSK(1)信号和BOC(1,1)信号在不同预相关带宽和不同相关器间隔时的平均加权多径误差包络进行了仿真,提取了多径误差典型值。结果表明,随着相关器间隔的减小,多径误差逐渐减小,但当相关器间隔为0.1个码片时,多径误差的减小已不明显;多径误差并不是随着预相关带宽的增大一直减小,而是有一... 相似文献
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在Galileo系统建设和GPS现代化的进程中,为实现与BPSK(Bi-phase Shift Keying)的频谱分离,采用了BOC(Binary Offset Carrier)调制。BOC调制在码跟踪精度、多径抑制等方面比BPSK调制具有更好的性能,但其自相关函数的多相关峰特性使得在测距中可能产生偏差,因此,消除相关峰的模糊度是BOC信号接收中非常关键的问题。介绍了一种基于QBOC码的BOC信号码跟踪环路(“BOC十QBOC-BOC”),并推导出该环路码跟踪性能的解析表达式,最后的仿真结果验证了理论推导的正确性,可为BOC信号接收机的设计提供参考。 相似文献
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针对导航信号的多径误差分析,在多径误差包络曲线分析方法基础上提出了多径误差包络期望分析方法。与包络曲线分析方法相比,包络期望分析方法能够定量分析导航信号多径误差。基于包络期望分析方法,对同码速率的二进制偏移载波(BOC)调制导航信号与二进制相位控键(BPSK)调制导航信号的多径误差进行了对比分析。结果表明,BOC调制导航信号具有更小的典型多径误差。 相似文献
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BOC调制信号多径误差分析 总被引:1,自引:0,他引:1
针对导航信号的多径误差分析,在多径误差包络曲线分析方法基础上提出了多径误差包络期望分析方法.与包络曲线分析方法相比,包络期望分析方法能够定量分析导航信号多径误差.基于包络期望分析方法,对同码速率的二进制偏移载波(BOC)调制导航信号与二进制相位控键(BPSK)调制导航信号的多径误差进行了对比分析.结果表明,BOC调制导航信号具有更小的典型多径误差. 相似文献
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《武汉大学学报(信息科学版)》2016,(2)
针对全球导航卫星系统(global navigation satellite system,GNSS)信号体制评估过程中,多径误差包络评估方法给出了多径误差的上界,并没有反映反射信号载波和子载波相位引入的码跟踪误差问题,提出了一种码跟踪多径误差非包络评估方法。该方法将反射信号的码相位延时映射到载波和子载波相位延时,为码跟踪多径误差提供了准确的理论值,而且避免了多径误差包络方法求包络曲线的过程。给出了该方法的理论表达式,对BPSK、AltBOC、MBOC和BOC信号进行了多径性能仿真,并与多径误差包络评估方法进行了对比。理论和仿真结果表明,本文方法能准确的估计码跟踪多径误差,为GNSS信号多径误差测量值提供有效的理论指导。 相似文献
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介绍了GPS与Galileo共用信号的演变过程,通过BOC(1,1)在兼容性、互操作性方面的表现,以及将MBOC(6,1,1/11)与之相比较,描述了MBOC(6,1,1/11)在这两个方面的表现。可供我国卫星导航信号体制设计借鉴学习,为GPS/Galileo接收机设计提供参考。 相似文献
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Weighted discriminators for GNSS BOC signal tracking 总被引:1,自引:1,他引:0
Modern Global Navigation Satellite System including Galileo and GPS III will employ multiplexed binary offset carrier (MBOC) modulation to achieve spectrum separation and enhanced tracking performance. A challenge of the MBOC or BOC signal tracking is the presence of ambiguities due to multiple sidepeaks of the autocorrelation functions. Several different techniques including multi-correlator and double estimator schemes have been proposed to address the ambiguity issue. We propose a class of ambiguity-free code tracking techniques by exploiting the unique features of the BOC modulation. In the proposed architecture, the incoming BOC-modulated signals are correlated with BOC-modulated replica and the spreading codes, respectively. Through a multiplicative combination strategy of the two correlator outputs, a noncoherent weighted discriminator is formed and shown to possess the ambiguity-free property. The multipath effect is assessed and compared with existing early-minus-late power and autocorrelation sidepeak cancellation technique discriminators. The noise effects of the theory and simulation are also discussed. In order to further verify the proposed scheme, a set of field data of a Galileo in-orbit validation satellite is collected and processed. It is demonstrated that the proposed method is simple to implement, free from ambiguities, and yields acceptable performance in the presence of multipath and noise. 相似文献
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With the proposed new GNSS signals, enhanced navigation performance is expected in both civil and military applications. However, these new signals introduce the difficulty of combining multiple signal components into a constant-envelope signal. For the Compass B1 band, the problem is to multiplex a QPSK(2) signal and a new multiplexed binary offset carrier (MBOC) signal with a center frequency difference of 14.322 MHz. One approach for multiplexing spreading codes is the phase-optimized constant-envelope transmission (POCET) method proposed for the GPS L1 band. However, only binary spreading codes are considered in POCET. We first generalize the POCET method as a multilevel POCET (MPOCET) algorithm for multilevel coded signals. A new implementation of the alternative binary offset carrier (AltBOC) generator is derived from MPOCET. Secondly, the multiplexing problem for Compass is modeled by MPOCET. Multilevel subcarriers of AltBOC are adopted in the model. As a result, an 8-PSK unbalanced AltBOC (UAltBOC) modulation, which has a QPSK(2) signal at the lower sideband and a TMBOC signal at the upper sideband, is obtained. Simulations for signal model validation and power spectrum analysis are conducted. Numerical results indicate that UAltBOC successfully combines the QPSK and TMBOC signals with only 0.16-dB additional combining loss compared to AltBOC. The proposed MPOCET technique is demonstrated as a unified multiplexing method for navigation signals. 相似文献
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