基于SIC的伪卫星系统抗远近效应捕获算法研究

SIC-based anti near-far effect acquisition method for pseudolites systems

  • 摘要: 地基伪卫星系统中由于远近效应的影响,近场伪卫星信号可能对远场伪卫星信号形成压制干扰,导致远场伪卫星信号无法被捕获. 针对该系统中使用的跳时直接序列扩频(TH-DSSS)信号的捕获问题,引入串行干扰消除(SIC)技术,缓解伪卫星系统中的远近效应问题,通过本地重构强信号和干扰对消降低强信号对弱信号捕获的影响,并从理论和仿真两方面对其性能进行了分析. 仿真结果表明,相比传统未采用干扰消除的捕获算法而言,基于SIC的信号捕获方法在不改变伪卫星基站结构和接收机框架的基础上,可有效降低远近效应的影响,提高弱信号捕获概率,扩大系统工作范围,从而为接收机在强远近效应场景下的捕获、跟踪和定位解算提供有效保障.

     

    Abstract: In the Ground-based Pseudolites System, near-field pseudolite signals may interfere and suppress the far-field signals since the existence of near-far effect, causing failure acquisition of the far-field signals. A SIC-based acquisition method anti near-far effect is proposed in this paper, aiming at the acquisition of time-hopping direct sequence spread spectrum (TH-DSSS) signal implemented in this system. Interferences of strong signals to weak signals are reduced by reconstructing local replica of the strong signal and interference cancellation. The proposed method is analyzed in theory and simulation. Simulation results indicate that the SIC-based acquisition method has the ability to reduce the influence of near-far effect, increase the detection probability of weak signals and enlarge the operating range of system without changing the pseudolite base station structure and the framework of corresponding receiver, which provides an effective guarantee for the receiver to capture, track and position in scenarios with strong near-far effect.

     

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