罗兰C信号TOA高精度估计算法

High precision TOA estimation method for Loran C signal

针对低频地波传播的罗兰C信号TOA(Time of Arrival)估计,提出一种采样周期内分数TOA的高精度估计算法。利用互相关获得有周期模糊的第三周过零点TOA估计值,采用改进的导出脉冲法的估计结果对其解模糊,获得第三周过零点采样周期整数倍的TOA估计值,最后以解模糊后的TOA估计值作为参考通过将其邻域内的离散信号插值为连续时间信号,由此连续时间信号的过零点得到小于一个采样周期的TOA估计。计算机仿真结果和实测数据验证了本文提出的罗兰C信号TOA估计的高精度性能和本文算法的有效性。

A high precision fractional TOA estimation algorithm is proposed for low frequency ground-wave propagation Loran C signal TOA estimation within a sampling period. The TOA estimate with cycle ambiguity of the third cycle zero crossing point is obtained from the cross correlation algorithm. An improved derived pulse method is used to resolve the ambiguity in TOA estimation,and then unambig uous TOA estimate of the third cycle zero crossing point which is an integer multiple of sampling period is found. Adopting this unambiguous TOA as a reference and interpolating the discrete signal within its neighborhood into a continuous signal,the fractional TOA less than the sampling period is obtained by finding the zero point of the interpolated continuous signal. Simulation and the real data processing results demonstrate the high precision,validity and feasibility of TOA estimation of the proposed method.