Underwater Acoustic Source Localization via an Improved Triangular Method

Underwater passive localization commonly faces the challenge of inaccurate arrival time when using time measurements as location features. This is because in the noisy underwater environment, the received signals are often over-whelmed by excessive noise. Several pseudo peaks might appear when adopting cross-correlation method to extract arrival time measurements. In this case, exploiting the angular information to locate an underwater target passively can be a more practi-cal choice. Triangulation is a classic ranging method used in passive sonar. Combing two angular measurements and one traveled distance, two-dimensional coordinates of the target can be obtained. In this paper, we propose an improved triangu-lar localization method based on azimuth-only measurements in underwater environment. Unlike the traditional triangular method, our proposed method changes the localization scenario and properly utilizes the movable surface vehicle to locate an underwater target for three times. Additionally, some appropriate optimization methods are employed to refine the final position. Numerous simulations are conducted to analyze the effects of signal-to-noise ratio (SNR), the traveled distances, the distance between the ship and the target on the positioning accuracy. The results prove that our proposed method outperforms the traditional one with respect to the localization accuracy in the case of low SNR. The method presented herein is more reliable for single target positioning in the noisy underwater environment. To some extent, it has much reference significance for the promotion of the traditional triangular method.