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Deep Net Localization - Eavesdropping in Mobile Acoustic Underwater Sensor Networks
Abstract
Navigation is a challenging task for underwater devices, as there is no global navigation system available. This often restricted Autonomous Underwater Vehicles (AUV) in their operations, either spatially because they depend on reference markers that need to be deployed on the mission side, or by dive time as they need to surface regularly to geo-reference themselves via satellite. For most applications the position and attitude information of an AUV is crucial for a meaningful interpretation of the collected data. In this paper, we present Deep Net Localization (DNL), a novel localization approach for stationary and mobile nodes in an acoustic underwater sensor network. For that purpose a communication protocol was developed that enables network nodes to self-localize their position and attitude in the network by eavesdropping on the communication of other nodes. This is achieved by combining modern acoustic USBL modems and pressure sensors with a Bayes estimator. Without the need to actively transmit acoustic signals, DNL saves energy and reduces
the overall workload of the communication channel. Furthermore this minimizes interference effects with other acoustic sensors, like multi-beam sonar, which are essential for the measurement purpose of a sensor node. In order to assess the approach we first tested the general functioning in a Monte-Carlo-Simulation.
Subsequently the method was evaluated with real data that was collected during a sea trial in the Middle Atlantic Ocean.
... In terms of error in the distance and the direction estimations, the performance of localization accuracy is compared within different mechanisms. Sergej Neumann, et.al proposed a novel localization technique with respect to the attitude estimation namely deep net localization [21]. There is no active data exchange required in this approach and in order to perform localization, regular communication is used within the network. ...
The underwater acoustic network is the type of network which is deployed under the deep sea or ocean to gather underwater information. The sensor node position estimation is a major issue of the underwater acoustic network. The process of estimating node position is called node localization. In the existing RSSI based approach for the node localization has a high delay which reduces its efficiency. The technique needs to be designed which localize a number of nodes in less amount of time. This research is based on the advancement of the range-based scheme for node localization. In the proposed scheme mobile beacons are responsible for the node localization. The beacon nodes send beacon message in the network and sensor nodes respond back with a reply message. When two beacons receive the reply of a sensor node that is considered as a localized node. The sensor nodes which are already localized will not respond back to the beacon messages which reduce delay in the network for node localization. The simulation of proposed modal is performed in MATLAB and it shows that proposed scheme performs well in terms of a number of nodes localized.
This report summarizes our research directions in un- derwater sensor networks. We highlight potential applica- tions to off-shore oilelds for seismic monitoring, equipment monitoring, and underwater robotics. We identify research directions in short-range acoustic communications, MAC, time synchronization, and localization protocols for high- latency acoustic networks, long-duration network sleeping, and application-level data scheduling.
In underwater sensor networks (UWSNs), determining the location of every sensor is important and the process of estimating the location of each node in a sensor network is known as localization. While various localization algorithms have been proposed for terrestrial sensor networks, there are relatively few localization schemes for UWSNs. The characteristics of underwater sensor networks are fundamentally different from that of terrestrial networks. Underwater acoustic channels are characterized by harsh physical layer environments with stringent bandwidth limitations. The variable speed of sound and the long propagation delays under water pose a unique set of challenges for localization in UWSN. This paper explores the different localization algorithms that are relevant to underwater sensor networks, and the challenges in meeting the requirements posed by emerging applications for such networks, e.g. offshore engineering.
Localization is a common problem in underwater
sensor networks. Since global navigation satellite systems do not work underwater, geo-referencing of underwater sensors requires other technologies. In this paper, we present an novel localization approach for nodes in an acoustic underwater sensor network. By combining pressure sensors with the functionality of modern acoustic USBL modems, the nodes are able to self-localize their position inside the network. This can be done in a passive manner, just by listening to the transmitted messages of other network nodes, thereby saving energy and sparing the communication channel from additional traffic. In order to evaluate the performance of the method, experiments have been conducted in simulation and under real conditions in the Middle Atlantic Ocean.
CLAWAR 2015: 18th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines
Zhejiang University, HangZhou, China, 6 – 9 September 2015
Edited by: Hongye Su ( Zhejiang University, China), Tianmiao Wang ( Beijing University of Aeronautics and Astronautics, China), Mohammad O Tokhi ( University of Sheffield, UK), Gurvinder S Virk ( University of Gävle, Sweden)
Successful deep-sea exploration (up to 6000m) performed by autonomous underwater vehicles (AUVs) depends heavily on accurate AUV localization. In the absence of GPS underwater, this requires acoustic communication, localization and geo-referencing underwater participants, e.g. by a GPS-positioned surface vehicle, which is necessary to periodically correct drift errors from deadreckoning. Within the SMIS project this is supposed to be achieved by a team of AUVs assisted by an unmanned surface vehicle (USV) and a sea-bed-station. In order to derive constraints for the team behaviour, the quality and stability of the acoustic localization needs to be examined thoroughly in advance. This delivers various constraints for later at-sea operation, e.g. the maximum distance between AUV and USV and the maximum horizontal distance to the USV for a given AUV depth. Additionally, heuristic estimates for reproducibility of long-range position measurements can be derived which indicate imminent errors based on acoustic localization only. This paper reports associated tests and their results using USBL modems in deep-sea trials performed in the Atlantic ocean.
This paper presents the joint research project “SMIS” with focus on the requirements and the design of the seabed station. A major issue for all autonomous subsea systems is the problem of limited battery capacity due to design boundary conditions. SMIS counteracts this by deploying an autonomous power-carrying vehicle, similar to a mobile petrol station, to extend the operation time for the AUVs.
The demands of the autonomous seabed station include the unguided submerge through 6000 m water column, a safe landing on suitable ground without excessive power consumption and a reliable docking mechanism for power transmission to AUVs on the sea floor. Moreover, the communication between the SMIS vehicle fleet for georeference and path guidance during the AUV operation is essential. A modular design also allows operation in ROV mode, which expands the field of application.
Unmanned surface vehicles (USV) increasingly gain importance in all areas of marine engineering and natural sciences. Different measuring vehicles are used for short-term measurements with various adaptable sensors. The operation time of these vehicles is limited to few hours. Moreover, long endurance vehicles were designed for long-term missions, generating energy from solar, wind or waves, which are suitable for low-power applications. This paper describes the conceptual design and automation aspects of an innovative ocean-going autonomously acting unmanned surface vehicle. As the vehicle should act as communication node for deep-sea communication up to 6.000 meters, the main challenge is designing a low noise vehicle with reduced motions in waves. The vehicle is supposed to operate autonomously for at least one week. Hence, a hybrid energy system has been designed using batteries and a fuel cell. The automation system allows the vehicle to solve missions in a full autonomous way with minimum operator intervention. The paper closes with aspects of the vehicle construction and first trials.
Underwater Wireless Sensor Networks (UWSNs) are expected to support a variety of civilian and military applications. In UWSNs, Medium Access Control (MAC) protocol has attracted strong attention due to its potentially large impact to the overall network performance. Unlike terrestrial networks, which mainly rely on radio waves for communications, UWSNs utilize acoustic waves, which pose a new research challenge in the design of MAC protocols. To present the development of MAC protocols in UWSNs, this paper surveys the current state-of-the-art MAC protocols for UWSNs. In the early development, the performance in terms of delay and throughput of the UWSNs has been the major concern of the MAC layer protocol design. Later, the design of energy-efficient MAC protocols becomes a new research focus because sensor nodes are generally powered by batteries which are less likely to be recharged. In this paper, we first describe the underwater acoustic environment and the challenges to the MAC protocols design in UWSNs. We then provide a comparative study of several types of MAC protocols according to current existing diverse implementations. Furthermore, open research issues will be summarized. Hopefully, this survey will inspire more active research in this area.
Ultra-short baseline (USBL) positioning systems and reliable data transfer systems for application on underwater vehicles have recently attracted significant interest. However, contemporary USBL transceivers and underwater acoustic modems operate separately in time and/or in different frequency bands. This paper presents a technical solution blending positioning and communication modes. Physical implementation of a combined positioning and communication device has been built upon the Sweep Spread Carrier (S2C) technology. Due to deep integration of a USBL positioning system with an underwater acoustic modem, the USBL antenna and the modem (apart of sharing the electroacoustic circuit) use also the same acoustic signal to transfer information and estimate the position of signal's source. A significant advantage of such a combined positioning and communication system consists in its ability to simultaneously track transponder/AUV movements and exchange instant messages and payload data with the transponder/AUV, enabling real-time control and navigation of the AUV based on actual positioning data. The paper presents experimental accuracy of the USBL estimating range and bearing of moving transponders in shallow waters, as well as data transfer rates obtained during data exchange in channels with strong reverberation.
Underwater Wireless Sensor Networks (UWSNs) are expected to support a variety of civilian and military applications. Sensed data can only be interpreted meaningfully when referenced to the location of the sensor, making localization an important problem. While global positioning system (GPS) receivers are commonly used in terrestrial WSNs to achieve this, this is infeasible in UWSNs as GPS signals do not propagate through water. Acoustic communications is the most promising mode of communication underwater. However, underwater acoustic channels are characterized by harsh physical layer conditions with low bandwidth, high propagation delay and high bit error rate. Moreover, the variable speed of sound and the non-negligible node mobility due to water currents pose a unique set of challenges for localization in UWSNs. In this paper, we provide a survey of techniques and challenges in localization specifically for UWSNs. We categorize them into (i) range-based vs. range-free techniques; (ii) techniques that rely on static reference nodes vs. those who also rely on mobile reference nodes, and (iii) single-stage vs. multi-stage schemes. We compare the schemes in terms of localization speed, accuracy, coverage and communication costs. Finally, we provide an outlook on the challenges that should be, but have yet been, addressed.
In this paper, we present a silent positioning scheme termed UPS for underwater acoustic sensor networks. UPS relies on the time difference of arrivals locally measured at a sensor to detect range differences from the sensor to four anchor nodes. These range differences are averaged over multiple beacon intervals before they are combined to estimate the 3-D sensor location through trilateration. UPS requires no time synchronization and provides location privacy at underwater vehicles/sensors whose locations need to be determined. To study the performance of UPS, we model the underwater acoustic channel as a modified ultrawideband Saleh-Valenzuela model: The arrival of each path cluster and the paths within each cluster follow double Poisson distributions, and the multipath channel gain follows a Rician distribution. Based on this channel model, we perform both theoretical analysis and simulation study on the position error of UPS under acoustic fading channels. The obtained results indicate that UPS is an effective scheme for underwater vehicle/sensor self-positioning.
A survey of practical issues in underwater networks
- Jim Partan
- Jim Kurose
- Brian Neil Levine