The Galileo navigation satellite system(Galileo)E5 Alternative Binary Offset Carrier(AltBOC)signal brings various challenges due to its complex modulation,wide bandwidth,and multi-peaked auto-correlation function.Whil...The Galileo navigation satellite system(Galileo)E5 Alternative Binary Offset Carrier(AltBOC)signal brings various challenges due to its complex modulation,wide bandwidth,and multi-peaked auto-correlation function.While wideband tracking needs to solve the ambiguity problem and design dedicated baseband channels,the single-sideband cannot have the outstanding performance of the AltBOC signal.We propose a new tracking method called“Double Sideband Combined Tracking”(DSCT),which can fully exploit the AltBOC signal’s code tracking accuracy without ambiguity and ensure compatibility with Binary Phase Shift Keying(BPSK)processing channels,easily implemented in hardware.The DSCT employs one phase locked loop and one delay locked loop to track the carrier and code,respectively.The double-sideband correlation results used by the two loops are recovered by coherently combining the singlesideband correlation results of the two BPSK channels.Meanwhile,the combined model,the loop discriminator,and the ambiguity detection of the DSCT are discussed.Furthermore,the code tracking error caused by thermal noise is modeled and analyzed.The test results based on real Galileo E5 signals show that the DSCT exhibits better or comparable code tracking accuracy to the AltBOC wideband tracking method.When the loop falsely locks onto a sidepeak,the DSCT can quickly detect and re-lock on the main peak.展开更多
基金This research is funded by the National Key Research and Development Program of China(No.2020YFB0505803)the National Natural Science Foundation of China(No.41974024).
文摘The Galileo navigation satellite system(Galileo)E5 Alternative Binary Offset Carrier(AltBOC)signal brings various challenges due to its complex modulation,wide bandwidth,and multi-peaked auto-correlation function.While wideband tracking needs to solve the ambiguity problem and design dedicated baseband channels,the single-sideband cannot have the outstanding performance of the AltBOC signal.We propose a new tracking method called“Double Sideband Combined Tracking”(DSCT),which can fully exploit the AltBOC signal’s code tracking accuracy without ambiguity and ensure compatibility with Binary Phase Shift Keying(BPSK)processing channels,easily implemented in hardware.The DSCT employs one phase locked loop and one delay locked loop to track the carrier and code,respectively.The double-sideband correlation results used by the two loops are recovered by coherently combining the singlesideband correlation results of the two BPSK channels.Meanwhile,the combined model,the loop discriminator,and the ambiguity detection of the DSCT are discussed.Furthermore,the code tracking error caused by thermal noise is modeled and analyzed.The test results based on real Galileo E5 signals show that the DSCT exhibits better or comparable code tracking accuracy to the AltBOC wideband tracking method.When the loop falsely locks onto a sidepeak,the DSCT can quickly detect and re-lock on the main peak.
文摘在移除二进制偏移载波(Binary Offset Carrier,BOC)信号跟踪模糊的同时,为了保持BOC信号高的码跟踪精度,提出基于加权鉴别函数(Weighted Discriminator Function,WDF)的BOC信号无模糊跟踪方法。WDF使用非相干超前减滞后功率(Noncoherent Early Minus Late Power,NELP)鉴别器和子载波相位消除(Sub Carrier Phase Cancellation technique,SCPC)鉴别器,生成无误锁点的鉴别函数实现BOC信号跟踪。针对BOC(10,5)信号,仿真结果表明,相比于SCPC、基于伪相关函数的无模糊延迟锁定环(Pseudo correlation function based Unambiguous Delay Lock Loop,PUDLL)方法和对称脉冲模糊移除(Symmetrical Pulse Ambiguity Removing,SPAR)方法,所提WDF方法在码跟踪误差方面分别改善了2.5dB、5.5dB与8.3dB,多径误差分别降为60.4%、32.8%与38.0%。因此,WDF是一种有效的、高性能的BOC信号无模糊跟踪方法。
