Abstract: The interference striation equation of the target in intermediate or short range has been derived combining with the concept of waveguide invariant,indicating that the striations are a family of quasi-hyperbolas in the shallow water.The waveguide invariant β,which reflects the environmental information,the heading angle φ and r₀/v,which is the ratio of the range of the closest approach point to the target velocity,can be estimated by processing the LOFARgram and time-bearing display using Hough transform.Both the simulation and sea-trial data analysis results show that stable interference structure of the low-frequency sound field can be observed and high accurate parameter estimation for moving target can be obtained by adopting a means of image processing.Passive ranging could be achieved based on the double elements model,and the simulation results show that the algorithm has higher positioning accuracy and better robustness.