摘要
远近效应反映了传播距离变化下信号间干扰对信号捕获、跟踪和电文解析的影响,是影响地基伪卫星定位系统定位精度和有效范围的关键因素。针对地基伪卫星系统在高精度定位中的应用,分析了远近效应对系统性能的影响,提出基于跳时改善远近效应的方法,分析了TH/DS-CDMA伪卫星信号体制改善远近效应的作用原理和改善程度,并提出在帧信号体制下系统跳时相关参数的一般设计方法。针对基于北斗参数的伪卫星仿真了系统测距误差和可用范围的分布特性。仿真结果表明,跳时体制可大幅提升地基伪卫星信号的测距性能和有效覆盖范围,跳时对载波相位测量的影响和在星地联合运行下的参数设计有待进一步研究。
The near-far effect is the influence of inter-signal interference depending on propagation distance on signal acquisition, tracking and data extraction, which is a key factor that affects the terrestrial pseudolites system＇s positioning accuracy and effective range.For terrestrial pseudolite system employed in high accuracy applications, the near-far effect on the system performance is analyzed, and a suppressing method based on time hopping is presented. The paper discusses the fundamental principles of TH/DS- CDMA（Time Hopping/Direct Sequence-CDMA）pseudolite signal and its improvement in suppressing near-fear effects, and presents a general design method of frame structure related parameters.A simulation of spatial distribution of pseudolite system＇s ranging error and effective range with Beidou related parameters is presented with satisfactory results that the signal structure can greatly boost the ranging and effectiveness performance.Further research is needed to focus on TH＇ s impact on carrier phase measurement and parameters design in GNSS-combined mode.
出处
《无线电工程》
2017年第6期27-31,共5页
Radio Engineering
基金
国家重点研发计划基金资助项目(2016YFB0502402)
