基于FPGA的S模式询问信号的侦收解码

S模式询问信号包括前同步脉冲和有效数据两个部分,且通过PAM和DPSK调制方式发送出去。针对其信号特点,从时域和频域考虑,给出两种解码方法,并对其计算机仿真结果进行了对比,得出互谱分析法抗干扰能力优于基于DFT解调法的结论。在ISE开发软件环境下,采用硬件编程语言VHDL,实现了基于FPGA的互谱分析解码设计。

Interception and decoding of the Mode S inquiry signal based on FPGA

The Mode S inquiry signal contains pre-synchronous pulses and valid data,and it is transmitted after PAM（pulse amplitude modulation） and DPSK（difference phase shift keying） modulation.Aimed at its characteristic,two decoding methods are proposed through clock domain and frequency domain.Comparing with each other,the computer simulation results indicate that the cross spectra analyzed method is good at anti-jamming and better than the demodulation based on DFT.Based on FPGA,the decoding design of the cross spectra analyzed method is realized under the ISE development software environment,using hardware programming language VHDL.