跳频信号的时差直接定位

针对跳频信号，提出了两种时差直接定位方法--最大似然直接定位法与最大相关累积直接定位法.第一种算法利用跳频信号频域有限分布特性，通过频域构造互相关函数（Cross Correlation Function，CCF）矩阵，在二维网格中搜索CCF矩阵的最大特征值得到目标的位置估计.第二种算法以各站与参考站的CCF之和为目标函数，直接在二维网格中搜索得到目标位置估计.两种算法进行了对比，第一种方法在性能上优于第二种，但计算量更大.蒙特卡洛仿真表明，提出的最大似然直接定位方法的性能是最优的，最大相关累积方法性能也优于传统的两步法.

TDOA-Based Direct Geolocation of Frequency-Hopping Signals

Two direct TDOA geolocation approaches are proposed for FH(Frequency-Hopping) signals-the maximum likelihood direct geolocation and the maximum correlation-sum direct geolocation.The first approach makes use of the sparsity of FH signals in frequency domain,and constructs CCF(cross correlation function) matrix in frequency domain,the location estimate is obtained by searching the max eigenvalue of CCF in a two dimensional grid.The second approach directly uses the sum of CCF,and searches in a two dimensional gird to find the location estimate.The comparison between them has been made,and the first approach performs better than the second one,but needs much more computation.Monte Carlo simulations validate that the accuracy of the proposed maximum likelihood direct geolocation method is the best,and the maximum correlation-sum direct geolocation method also outperforms the two-step method.