STRUCTURAL DYNAMICS OF THE INTERNATIONAL SPACE STATION USING DATA FROM THE LASER DYNAMIC RANGE IMAGER

摘要

The International Space Station (ISS) represents a unique structure that has a high density of ultra low frequency modes, sparse instrumentation, on-orbit construction, and the need for validated models. To allow the measurement of large uninstrumented sections of this structure in a non-contact fashion, a system called the Laser Dynamic Range Imager (LDRI) has been developed. This system uses diffuse modulated laser illumination coupled with an intensity modulated video receiver to produce video and range images. The output data includes displacement time histories from 250,000 active pixels from the range as well as the two cross-plane directions. The hardware is currently mounted on the Space Shuttle Orbiter Endeavor and is scheduled to be exercised on-orbit as part of ISS assembly flight 4A (also called STS-97) in December of 2000. The analysis software provides the diverse functions of image processing, spatial calibration, range extraction, point tracking, digital signal analysis, coordinate transformation, and traditional modal analysis. Ground-based testing has provided opportunities to verify and develop the sensor and analysis products.