非理想信道下测量零值无偏干扰抑制滤波器设计

现有的抗干扰滤波器在通道非理想特性下会导致接收机测量零值发生偏移,且偏移量与干扰参数相关,其已成为高精度测距接收机实现其精度提升的主要障碍。针对上述问题,从对称通道特性出发,给出一种无偏的时域抗干扰滤波器设计技术。解决了传统的时域抗干扰滤波器在非理想信道下测量零值偏移的问题,且工程实现简单。理论分析和仿真实验进一步验证了方法的有效性,采用该方法可以使测量零值偏移小于0.2 ns。

Zero bias anti-jamming filter design in non-ideal channel

The tap weights of anti-jamming filter always be constrained, in order to mitigate the tracking bias which introduced by anti-jamming filter. The premise of these methods is that the receiver channel is ideal. However the analog receiver channel is not ideal in practice, where the magnitude and phase responses are not constant across the range of the passband. So there is non-zero bias for the GNSS receiver due to the anti-jamming filter and the bias. Furthermore, since the tap weights of the adaptive transversal filter varies based on jamming pattern, the bias will also vary. The bias is always in nanosecond time scale in practice. This problem of code tracking bias has been a significant hurdle to achieving interference suppression capabilities in precision GNSS applications. Aiming at this problem, using the symmetrical characteristic of non-ideal analog receiver channel, a new technique called zero bias anti-jamming filter is presented. The proposed method can be easy implement in engineering. Theoretical analysis and simulative results show that the proposed method is capable of reducing the bias to less than 0.1ns, which is significantly smaller than the traditional adaptive anti-jamming filter.