Preliminary deep water results in single-beacon one-way-travel-time acoustic navigation for underwater vehicles

Abstract

Abstract-This paper reports the development and experimental evaluation of a novel navigation system for underwater vehicles that employs Doppler sonar, synchronous clocks, and acoustic modems to achieve simultaneous acoustic communication and navigation. The system reported herein, which is employed to renavigate the vehicle in post-processing, forms the basis for a vehicle-based real-time navigation system. Existing high-precision absolute navigation techniques for underwater vehicles are impractical over long length scales and lack scalability for simultaneously navigating multiple vehicles. The navigation method reported in this paper relies on a single moving reference beacon, eliminating the requirement for the underwater vehicle to remain in a bounded navigable area. The use of underwater modems and synchronous clocks enables range measurements based on one-way time-of-flight information from acoustic data packet broadcasts. The acoustic data packets are broadcast from the single, moving reference beacon and can be received simultaneously by multiple vehicles within acoustic range. We report experimental results from the first deep-water evaluation of this method using data collected from an autonomous underwater vehicle (AUV) survey carried out in 4000 m of water on the southern Mid-Atlantic Ridge. We report a comparative experimental evaluation of the navigation fixes provided by the proposed synchronous acoustic navigation system in comparison to navigation fixes obtained by an independent conventional long baseline acoustic navigation system.

Underwater sensor networks: applications, advances and challenges

“…SDME exploits post-facto localization (analogous to postfacto time synchronization of reference-broadcast synchronization [39]) to reduce message counts using an otherwise standard scheme based on all-pairs, broadcastbased, inter-station ranging. They observe localization accuracy of about 1 m at ranges of 139 m. The system of Webster et al [44] uses a single moving reference beacon (with global positioning system based position) to localize a moving AUV. Their localization scheme is based on acoustic ranging between vehicles with synchronized, high-precision clocks, combined with AUV location estimates from inertial navigation, combined post-facto with an extended Kalman filter.…”

Advances in decentralized single-beacon acoustic navigation for underwater vehicles: Theory and simulation

“…Previous work in the area of single-beacon navigation is extensively reviewed in [27]. This section reviews some of the references most relevant to this paper.…”

“…Navigation with a single, fixed beacon whose position is known a priori has been reported using several different estimation techniques-a least squares approach in [21] and [1], and a vehicle-based extended Kalman filter (EKF) in [16] and [10]. Navigation with respect to a moving beacon whose position is not known a priori is reported in [17] using a nonlinear least mean square method; in [6] using a maximum likelihood method; and in [27] using a centralized EKF. However, each of these methods, as reported, is only structurally tractable for post-processing, though the authors of [17] suggest improvements that would allow for real-time implementations.…”

“…The acoustic messages are broadcast from a single reference beacon that has knowledge of its position in the world frame [4], [6], [27], e.g. a vehicle or ship that is equipped with a GPS receiver.…”

“…Using underwater modems to combine acoustic communication and navigation, the vehicles employ one-way-travel-time (OWTT) navigation to estimate their own position using ranges from a single georeferenced beacon. The ranges are measured from the one-way travel-time of acoustic broadcasts from the reference beacon and require no centralized processing [4], [6], [27], [28].…”