基于自适应核时频分布的多普勒频移及多径时延估计

对修正时频相关函数多径时延估计法作了改进，提出了两种基于自适应核时频分布的LFM脉冲声纳目标回波多普勒频移及多径时延的联合估计方法。即首先利用目标回波及发射信号的先验信息，构造抑制交叉项的时频分布，再利用WVD峰值法及Radon-Wigner变换法进行参量估计。最后，仿真实验验证了该方法的有效性。

On Improving Joint Estimation of Doppler Frequency and Multipath Time Delay of Overlapping Echoes for LFM Pulse Sonar

For LFM (linear frequency modulation) pulse sonar, the method, based on modified time frequency correlation, for joint estimation of Doppler frequency and multipath time delay of overlapping echoes, can, in our opinion, be improved. Section 2 reviews the method in Ref. 8 and then improves it; our improved method utilizes Radon Wigner transform; so, we call this method, for short, the Radon Wigner transform method. In our opinion, there is still a better way for making such joint estimation. Section 3 presents an adaptive kernel distribution for reduction of cross terms. Section 4 uses this adaptive kernel distribution and Radon transform for joint estimation. We call this better improved method the Radon RID (RID stands for reduced interferences distribution) transform method. Table 1 lists simulation results, for three methods: (1) method in Ref.8 (M1 in Table 1), (2) Radon Wigner transform method ( M2 in Table 1), (3) Radon RID transform method ( M4 in Table 1). These results show preliminarily that Radon Wigner transform method and Radon RID transform method, both proposed by us, are much better than the method of Ref.8 and that Radon RID transform method is better than the Radon Wigner transform method in joint estimation of Doppler frequency and multipath time delay of overlapping echoes for LFM pulse sonar.