Radiometric sensitivity and resolution of synthetic tracking imaging for orbital debris monitoring

We consider sampling and detection strategies for solar-illuminated space debris. We argue that the lowest detectable debris cross-sectional area (corresponding to a factor of 3-10x in diameter) may be reduced by 10-100x by analysis of stacks of image frames collected at high rates rather than single frame data. In particular, instead of a pixel as a spatial region, the analysis is based on a "phase-space-pixel" which corresponds to an angular velocity and space region and whose intensity is computed by a weighted stacking of spatial pixels corresponding to a test debris trajectory within a wide camera field-of-view (FOV). To isolate debris signals from background, the exposure time is set to match the time it takes for debris to transit through the instantaneous field of view. Debris signatures are detected by multiscale X-ray processing of the data cube. Radiometric analysis of line integrals shows that sub-cm objects in Low Earth Orbit can be detected and assigned full orbital parameters by this approach.