Abstract: An apparatus configurable as a back support and as a boarding ladder for use with an inflatable boat is disclosed. The apparatus includes a first frame configured for mounting on an inflated tube of the inflatable boat and a second frame, pivotally coupled to the first frame, the second frame having a transverse element. The second frame is moveable, with respect to the first frame, between a raised position, where the transverse element provides a back support, and a lowered position where the transverse element provides a rung of a boarding ladder. The apparatus may also include one or more third frames that extend below the second fame when the second frame is in the lowered position, the one or more third frames providing one or more additional rungs of the boarding ladder.

Abstract: An apparatus configurable as a back support and as a boarding ladder for use with an inflatable boat is disclosed. The apparatus includes a first frame configured for mounting on an inflated tube of the inflatable boat and a second frame, pivotally coupled to the first frame, the second frame having a transverse element. The second frame is moveable, with respect to the first frame, between a raised position, where the transverse element provides a back support, and a lowered position where the transverse element provides a rung of a boarding ladder. The apparatus may also include one or more third frames that extend below the second fame when the second frame is in the lowered position, the one or more third frames providing one or more additional rungs of the boarding ladder.

Abstract: A method and apparatus for monitoring impacts on or between bodies is disclosed. In one application, head impacts and the performance of a helmet during impacts are monitored by determining head motion and helmet motion relative to a common origin and/or frame of reference in response to sensed head motion and sensed helmet motion. The head motion in the common frame of reference is compared with helmet motion in the common frame of reference to determine performance of the helmet. The apparatus may include a surface-mountable motion sensor having a reusable sensing circuit and a disposable mounting structure.

Abstract: A method and apparatus for providing back support for a user seated on an inflated tube of an inflatable boat. A support element, which supports the user's back, is coupled to one or more anchor points within the boat via circum-tubular coupling elements that prevent the support element from rotating about the tube.

Abstract: A method and apparatus for providing back support for a user seated on an inflated tube of an inflatable boat. A support element, which supports the user's back, is coupled to one or more anchor points within the boat via circum-tubular coupling elements that prevent the support element from rotating about the tube.

Abstract: A method and apparatus for monitoring motion of a substantially rigid body relative to at a first location, in which linear and rotational motions are sensed by one or more motion sensors attached to the substantially rigid body at other locations. The sensed rotation is used to compensate for the angular and centripetal acceleration components in the sensed linear motion. In one embodiment, the components are estimated explicitly from the sensed rotation. In a further embodiment, the sensed rotations are used to estimate the relative orientations of two or more sensors, enabling the linear motions to be combined so as to cancel the angular and centripetal accelerations. A reference sensor may be used for in-situ calibration. When the substantially rigid body is a human head, the reference sensor may be coupled to a helmet or mouthguard.

Abstract: A method and apparatus for monitoring motion of a rigid body, such as a head, in which a plurality of reference sensors are attached to a calibration structure, such as a helmet, and a plurality of body-mountable sensors are adapted for mounting on the rigid body. Once mounted, the positions and orientations of the body-mountable sensors may be unknown. In operation, a processing unit receives signals from the reference sensors and the body-mountable sensors and determines calibration parameters for the body-mountable sensors. The calibration parameters depend upon the sensitivity of the body-mountable sensors to linear, rotational and centripetal motions. These sensitivities, in turn, are dependent upon the positions and orientations of the body-mountable sensors. Body motion is determined from the body-mountable sensors using the calibration parameters.

Abstract: A method and apparatus for estimating the positions of sensors in an array of connected sensors. The sensors are operable to sense a propagating phenomenon, such as an acoustic disturbance in water or air. For each sensor i in the array of connected sensors, the direction vector di that corresponds to a direction of propagation between a reference point and the sensor i is measured. The position of the sensors relative to the reference point are determined dependent upon the vectors di. Additional information, such as propagation time, sensor orientation, and/or the lengths of the connections between sensors may be used. Optionally, the direction d are found using a singular value decomposition of a matrix formed from vectors of sampled signals components.

Abstract: An active control system for attenuating tonal noise in a defined region is described. In its most basic form the system includes sensors for generating signals indicative of the residual noise in the region after attenuation and the uncontrolled sound affecting the region, signal processing circuit for processing the generated signals differently depending on the tonal content thereof, an adaptive filter supplied with at least one of the generated signals whose characteristic is controlled by the processing circuitry, a transducer for producing tonal-noise-attenuating disturbance in the region and delay means for delaying signals relating to the uncontrolled noise before or after or during the adaptive filtering. The system finds direct application in a personal headset or ear defender.