Anchorless underwater acoustic localization

Abstract

We consider the problem of estimating the trajectory of a submerged source emitting acoustic signals without using any anchor nodes or receiving array. This approach is required for several applications, including the localization of acoustic sources such as marine mammals or underwater vehicles, for which the cost of covering a broad area with multiple receivers would be excessively high. Since multi-lateration is impossible in this scenario, we perform localization by incorporating bathymetry information. Specifically, we assume that the receiver retains knowledge of the environmental parameters that affect the signal propagation, and that the bathymetry of the area is sufficiently diverse to induce distinguishable channel impulse responses for different source locations. Our method compares the channel estimates obtained from the received acoustic signals against a database of channel responses, pre-computed through an acoustic ray tracing model. The set of possible node locations that result are then organized in trellis form to obtain a final estimate of the source's trajectory via a path tracking method similar to the Viterbi algorithm. Our results show that the proposed approach can estimate node locations and paths with very small error, provided that the receiver has sufficiently accurate and up-todate environmental information.

Model Free Localization with Deep Neural Architectures by Means of an Underwater WSN

“…Note that, if the training is performed with real data, with the WSN deployed, the training would also bring the advantage of adaptability because the localization DNN will learn to locate implicitly using the concrete geometry of the zone. This is an advantage that anchorless methods such as [9] also have, with the important difference that we do not need to map the sea region since the localization DNN will infer that by itself during the training phase, considerably reducing the computational load.…”

“…One solution to this problem is the use of self-localization algorithms [8]. Another solution is the use of an anchor-less localization mechanism that relies on fingerprinting [9], but this method needs to model the environment. Active messaging means that the sensors, as well as the target to locate, communicate among them in order to obtain the localization, which means having an increase in battery consumption and having a cooperative target.…”

Underwater Wireless Sensor Networks: A Survey on Enabling Technologies, Localization Protocols, and Internet of Underwater Things

“…Those receivers should be deployed in the underwater bottom to cover a wide area to ensure the target detection and localization, which is not useful in a real scenario. While most of the proposed localization schemes require the use of anchor nodes to estimate the position of a submerged acoustic source [91], authors in [92] proposed an anchorless localization method. In their work, the CIR of the received signal is modeled for multiple possible locations using bathymetry information.…”

“…The best CIR model location that fits with the measured one is kept in a set of possible node locations; then a trellis form is created from this set to obtain the final source trajectory estimation using a path tracking process similar to the Viterbi algorithm. Instead of accurate sensor node localization, authors in [92] aim to reduce the energy consumption and computational complexity of the localization scheme through reducing the communication between nodes. As the later cited work [92], the scheme presented in [93] is anchor-free.…”

“…Instead of accurate sensor node localization, authors in [92] aim to reduce the energy consumption and computational complexity of the localization scheme through reducing the communication between nodes. As the later cited work [92], the scheme presented in [93] is anchor-free. The exact location of the sensor node is calculated by its depth obtained from the attached sensor pressure combined to the two-dimensional information given by the AUV.…”