This paper describes a decision theoretic approach to real-time obstacle avoidance and path planning for a mobile robot. The mobile robot navigates in a semistructured environment in which unexpected obstacles may appear at random locations. Twelve sonar sensors are currently used to report the presence and location of the obstacles. To handle the uncertainty of an obstacle’s appearance, we ado...

mpulsive Echo Ranging systems are air-deployed, active, multistatic sonar systems designed to operate in both littoral and open-ocean areas. Sources ensonify a target, and multiple receivers detect resulting short-duration echo signals. Because the source illuminates ocean bottom features, particularly in shallow littoral waters, and the ocean is rich in independently generated transients, the ...

This paper describes our approach for the RoboCup 2006 Rescue League. The mobile system we use is based on an ActivMedia Pineer 3 AT. It is equipped with a four wheel drive and sonar sensors in the front and in the back. On this platform, an alumnium rack is installed where the other devices are attached to: A self made stereo camera system (consisting of two high resolution Sony FireWire camer...

This paper describes using a mobile robot, equipped with some sonar sensors and an odometer, to test navigation through the use of a cognitive map. The robot explores an office environment, computes a cognitive map, which is a network of ASRs [33, 34], and attempts to find its way home. Ten trials were conducted and the robot found its way home each time. From four random positions in two trial...

We present a novel approach to estimating depth from single omnidirectional camera images by learning the relationship between visual features and range measurements available during a training phase. Our model not only yields the most likely distance to obstacles in all directions, but also the predictive uncertainties for these estimates. This information can be utilized by a mobile robot to ...

We present a novel split and merge based method for dividing a given metric map into distinct regions, thus effectively creating a topological map on top of a metric one. The initial metric map is obtained from range data that are converted to a geometric map consisting of linear approximations of the indoor environment. The splitting is done using an objective function that computes the qualit...

With conventional time-of-flight sonar ranging systems, it is impossible to differentiate a reflection from a plane and from a rightangle corner reflector. A multitransducer pulse/echo ranging system is described that differentiates these two reflectors by exploiting the physical properties of sound propagation. The amplitudes and ranges of reflected signals for the different transmitter and re...

People who attend to the problem of underwater port protection usually use sonar based systems. Recently it has been shown that integrating a sonar system with an auxiliary array of magnetic sensors can improve the effectiveness of the intruder detection system. One of the major issues that arise from the integrated magnetic and acoustic system is the interpretation of the magnetic signals comi...

Using sonar to detect submarines used to be an effective method. Current technologies, however, have made it possible for submarines to thwart standard (active or passive) sonar mechanisms [1]. One viable alternative is to use magnetic or acoustic sensors in close proximity to possible underwater pathways a submarine may pass through. This approach may require deploying large-scale underwater s...

A baffled arc array (BAA) comprises a circular array of sensors surrounding a cylindrical metal baffle, and beamforming is carried out by processing sensors on an arc centred on beamsteer. It is widely used in sonar for passive underwater surveillance. An important factor that limits the performance of the array at high frequencies is the appearance of grating lobes in the beamformer response. ...