基于IFFT频谱相除的罗兰C天地波识别新算法

目前模拟接收机的周期识别复杂、识别时间长，而相关文献提出的算法在罗兰C天地波到达时间间隔小于50时估计误差大。为了准确估计时间间隔小于50的天地波到达时刻，在IFFT频谱相除技术基础上提出天地波分别识别的新算法。在证明了方法可行性的基础上，采用该算法仿真分析了天波以及地波自动识别的准确性。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6dB。

A New Loran C Sky-Wave and Ground-Wave Identification Algorithm Based on IFFT Spectral Division

For present analog Loran C receiver, it is very complicated and takes a long time to complete cycle identification. Moreover, estimate error when arriving time of sky-wave and ground-wave is less than 50 under algorithms presented by some relative documents is intolerant. For estimating the arriving time of sky-wave and ground-wave exactly, a new algorithm for the detection is presented based on IFFT(Inverse Fast Fourier Transform) spectral division. After proving its feasibility, veracity of arriving time for sky-wave and ground-wave is simulated. The results show that using the new algorithm, veracity of arriving time for sky-wave and ground-wave can get up to 99.6% and no less than 98.6% respectively，and signal to noise ratio (SNR) can be improved 6dB relative to the standard of USCG.