Abstract: A method of determining the stiffness and condition on a wooden structure. The method consists of initiating the natural vibration of the structure in a band of frequencies that cover at least two of the first five resonant modes of vibration. An electrical response equivalent to the vibration motion of the structure is generated and the electrical response is converted to a digital signal. The resonant frequency of the structure is calculated by analysing the digital signal. By comparing the results with the results obtained using a mathematical model the stiffness and condition of the structure is determined.

Abstract: The present invention provides a method and apparatus to determine the position, velocity and orientation of an object with respect to an observation point. It consists of placing a sensor spaced from the object and placed at the observation point which will emit two non-parallel beams of light toward the object. Retroreflectors on the object will reflect the light in opposite direction to generate pulses of reflected light caused by the angular relative motion between the incident beam of light and the retroreflectors. A processor can be used to provide an indication of the position, velocity and orientation of the object based on the time interval between reflected pulses.