基于时延和相位估计的合成孔径声呐运动补偿研究

合成孔径声呐成象的难点之一在于孔径上载体的运动不稳定性影响了合成孔径上水听器接收的信号的相干性,其结果将导致图像的畸变和分辨率的降低。首先讨论了运动误差对合成孔径声呐(SAS)成像的影响及运动补偿的必要性。在分析位移相位中心运动补偿法的基础上,提出了一种改进算法。该方法首先估计时延,然后再对剩余误差进行相位估计,从而扩大了算法适用的运动误差范围。文中给出了利用该方法的计算机仿真结果和部分水池实验结果,从结果可以看出,该方法有效地修正了在合成孔径上由于介质和载体不稳定带来的不相干性,提高了成像的质量。

A Study on SAS movement compensation based on time delay and phase estimation

A Study on SAS Movement Compensation Based on Time Delay and Phase Estimation Abstract One difficulty of SAS (Synthetic Aperture Sonar) imaging lies in that vehicle instabilities within the aperture length affects the coherence of hydrophone data over the length of the synthetic aperture, which results in distorted images and loss of resolution. Influences of movement errors on synthetic aperture sonar image results and the necessity of movement compensation are discussed firstly. Based on analyzing the so-called displaced phase center algorithm, an improved algorithm is proposed. With this method, the time delay is estimated firstly, then the residual phase error. Through this way the movement error range that can be compensated by this algorithm is extended. Some simulation results on computer and experimental results in the test tank using the proposed algorithm are given in the end of this paper. It can be seen from these results that this algorithm compensates the incoherence caused by movement and medium instability effectively and the imaging quality is improved.