Laser Vibrometry System for Space Situational Awareness

CTI proposes to develop a ground-based coherent laser radar for satellite vibration measurements. This system will be designed to make measurements of surface vibrations of satellites in orbits of up to 1000 km altitude. The vibration measurements will yield velocity power spectral densities up to 1 kHz. The proposed system will also be designed to work with existing telescope and satellite tracking facilities. The proposed Phase I research will include accurate modeling of the velocity estimate noise sources in the vibrometer. Key noise sources include local oscillator laser shot noise, local oscillator frequency instability, atmospheric refractive turbulence, and speckle noise due to relative motion between the sensor and the target. In the analysis, dominant noise sources will be identified and techniques for mitigation of these noise sources will be studied. Possible methods of noise mitigation include improved laser frequency stability and a variety of diversity techniques for mitigating speckle noise. The proposed Phase I research will conclude with a preliminary design of a Phase II sensor meeting the requirements established in Phase I.