针对可见光定位的信源在空间传输中抗干扰能力差、易失真,且接收信号的信噪比(SNR)会随传输距离的增加而显著降低等问题,设计了一款线性调频(LFM)信号同步检测的时域匹配滤波器。该匹配滤波器的特点是结合了过采样与互相关正交算法,将它应用在LFM信号的可见光定位中,可以有效地提高信号传输的距离。基于现场可编程门阵列器件完成了LFM时域匹配滤波器的逻辑设计与集成。在长距离可见光通信的同步检测实验中,在6 m通信距离内,该匹配滤波器同步检测的正确率超过99%,这为将来采用LFM信号进行可见光定位的应用奠定了基础。

This paper presents a time-domain matched filter for synchronous detection of linear frequency modulation (LFM) signals to consider the influence of poor anti-interference ability and distortion of visible light location source in space transmission and the signal to noise ratio (SNR). The SNR of a received signal decreases significantly with the increase in transmission distance. The matched filter is characterized by a combination of oversampling and a cross-correlation orthogonal algorithm. The application of the proposed filter to the visible light location of the LFM signal effectively improves the signal transmission distance. The logic design and integration of the LFM time-domain matched filter are completed using a field programmable gate array. In the synchronous detection experiment of long-distance visible light communication, the accuracy of synchronous detection of the matched filter is more than 99% at a communication distance of 6 m, which lays a foundation for the application of the LFM signal in the visible light location in the future.