脉冲干扰对软件接收机的影响分析

Analysis of Pulse Interference Effects on the Software Receiver

关键词:  卫星导航  多相关器  捕获  跟踪  脉冲干扰

Key words:  Satellite navigation  Multi-correlator  Acquisition  Tracking  Pulse interference

摘要:

卫星信号经过长距离传播,信号能量损耗严重,到达地面的功率很弱,容易受到各种干扰的影响。脉冲干扰为常见的干扰类型,所以针对不同功率、不同周期,以及不同占空比的脉冲干扰信号,通过接收前端采集受脉冲干扰的GPS L1信号,利用软件接收机及多相关器生成技术,详细分析了脉冲干扰对接收机信号捕获与跟踪性能的影响。分析结果表明,周期为1ms的脉冲干扰信号,能对接收机产生强烈的干扰效果,捕获图中的噪声明显增大;跟踪过程中,载噪比和相关值突发性减小,造成跟踪数据异常。而长周期的脉冲信号仅在脉冲到达时影响接收机的捕获和跟踪,但由于信号跟踪不能连续进行,导致伪距观测量的不连续与导航数据不能正常解码,从而干扰接收机。

Abstract:

After long distance transmission, the power of satellite signals reaching the ground experiences serious loss and is very weak.Thus, the signals can easily be affected by various kinds of interference.As pulse interference is a typical interference, the effects of the periodic pulse interference with different power, period and duty cycle on the GPS L1 signals are analyzed in the paper.Firstly, the interfered GPS L1 signals are collected by a GNSS Front End and analyzed in a software receiver.Then, we focused on the pulse interference effects on the acquisition and tracking processes of the receiver and multi-correlators are used to generate the auto-correlation function.Finally, the test results show that the pulse interference with a short period (1ms) degrades the receiver performance significantly.In acquisition process, the noise level increases and the peak value referring to the satellite signal reduces correspondingly.The values of the correlation and C/N0 decrease suddenly during tracking process.However, the pulse interference with a long period affects the receiver only when the pulse arrives.The discrete signal tracking leads to discontinuous pseudorange measurements and abnormal navigation data, hence the receiver is interfered