一种基于FFT/IFFT技术的罗兰C天地波识别新算法

A new Algorithm for Sky-Wave and Ground-Wave Detection of Loran C Based on FFT/IFFT Technology

罗兰C天、地波到达时间间隔小于50μs时，对天、地波到达时刻的估计误差大。为了准确估计时间间隔小于50μs的天、地波到达时刻，在FFT/IFFT技术基础上采用了天、地波分别识别算法，并证明了该方法可行性。仿真结果表明：利用该算法，天地波自动识别的准确率分别可达99．6％和98．6％以上，相对USCG标准可改善信噪比4．4dB，对数字化罗兰C接收机的研究与设计具有重要意义。

The estimate error for arriving time difference between ground-wave and sky-wave is large when their arriving time is tess then 50μs for Loran C receiver. For estimating the arriving time of sky-wave and ground-wave exactly, a new algorithm for the detection was presented based on FFT/IFFT, and its feasibility was proved. The simulation results showed that veracity of arriving time for sky-wave and ground-wave could be up to 99.6% and no less than 98.6% respectively using the new algorithm, and signal to noise ratio could be improved 4.4 dB compared with USCG standard. That is very important for the research and design of digital Loran C receiver.