Increasing the accuracy of time-frequency detection in engineering is always the goal that scientists are striving to achieve, because it is widely applied in the fields of Radar, Sonar, the exploration of earthquake epicenter etc. The current high-resolution time-frequency methods are mostly based on the structure of time-frequency distribution function of Cohen Family. Time frequency distribution function can trace the instantaneous frequency of nonstationary signal. This paper combines the process principle of multi-aperture Radar and Array signal and applies time-frequency distribution function in DOA of active sensor devices. By decoding of physical characteristics from the changes of frequency, which can be done by using the active devices to detect the response signal of the target and the analyzing the nonstationary changes of frequency caused by the delays of time and phase, the related positions and contained angle of target and reference can be found and practically applied to the target DOA of aircraft and vehicle engineering. By doing that, the troublesome multidimensions Fourier projection calculations, eigen factoring and Spectrum scan can be avoided and reduces the huge amount of active dynamic sensor devices required for vehicles, but not all of the distribution functions can be used to analyze the multi-objects. For example, Wigner distribution function is one of the case, because it contains the high cross-terms and is easily to be interfered by noise. In this paper, the application of a new time-frequency distribution function MACK (Modified Adaptive Cone Kernel) is proposed. The application general form is derived and proved, also the signals of time-varying spectrum are decoded. MACK can eliminate all of the cross-terms and the time-frequency analysis ability is high and uniform. The simulation results showed that the MACK function is very realistic and useful on aircraft navigation and vessel location.
Chang, Shun-Hsyung; Liu, Jun-Cheng; and Chiu, Chih-Wei
"Applying Time-Frequency Distribution Function to DOA of Mobile Active Sensor,"
Journal of Marine Science and Technology: Vol. 9:
2, Article 12.
Available at: https://jmstt.ntou.edu.tw/journal/vol9/iss2/12