Time delay signal process assisted by virtual instrument

Time delay estimation is the basis of target orientation of multi-sensor network, while the preliminary analysis and processing of the time delay signal is very important to the time delay estimation. In this paper, a virtual instrument time delay analysis system is designed, which contains: a virtual oscilloscope, a virtual spectrum analyzer, a virtual filter and a virtual time delay analyzer. By the use of this analysis system, the spectrum of the acoustic target signal collected in the field is analyzed. Analysis shows the main frequency of the target signal: 85Hz, 20Hz, 170Hz, 125Hz. Significance of the time delay peak is proposed to describe the validation of the cross-correlation result. Based on the three main frequency components, signals were filtered by the three filters and analyzed separately. The time delay estimation has been carried out for several sampling data segments selected by certain rules. Results were shown in figures of time delay vs. time and significant ratio vs. time. Each curve in a figure corresponds to a certain number of points of cross correlation. According to the results, the frequency component from 155Hz to 180Hz is much more suitable for practical use. The regular pattern of the time delay curve is consistent with the target motion. Application reveals that the system is helpful in the research of time delay estimation.