Underwater Transmitter Localization Based on TDOA and FDOA Considering the Unknown Time-Varying Emission Frequency

Abstract

This article considers locating a noncooperative underwater transmitter utilizing multiple receivers, such that each receiver can measure the frequency difference of arrival (FDOA) as well as the time difference of arrival (TDOA) of the transmitter’s sound. This article considers the case where the unknown emission frequency of the transmitter changes as time goes. This article addresses hybrid TDOA-FDOA localization, under the assumption that the transmitter’s maximum speed is known in advance. To the best of our knowledge, this article is unique in tackling hybrid TDOA-FDOA localization, considering the case where the unknown emission frequency changes as time goes on. Under MATLAB simulations, this article shows that the proposed hybrid localization method is comparable to the ideal case, where the time-varying emission frequency is known in advance. Furthermore, we show that the proposed localization approach outperforms the case where the emission frequency is estimated as a wrong value.

A Co-Localization Algorithm for Underwater Moving Targets with an Unknown Constant Signal Propagation Speed and Platform Errors

“…In (7), 23 , , , τ and , , τ , respectively, represent the measured frequency difference parameter vector and the actual frequency difference parameter…”

“…Signal strength is influenced by water temperature, salinity, and flow velocity, resulting in low positioning accuracy. Combining the AOA and TDOA can only be used to estimate the position of the target [19,21], so currently, joint TDOA/FDOA positioning is often used for mobile target localization [8,22,23], which can achieve the estimation of the position and velocity to the target. However, this method demands the participation of at least five or more platforms in the localization, significantly elevating its economic costs and deployment complexities.…”