Inverse Synthetic Aperture LADAR for Geosynchronous Space Objects - Signal-to-Noise Analysis

Inverse synthetic aperture LADAR ISAL provides high resolution images which are not limited in resolution by the diffraction limit of the telescope collecting the imaging data. This makes it an ideal method for imaging Geosynchronous Earth Orbit GEO space objects. Although LADAR is a well researched topic, little has been published on the suitability of ISAL for imaging GEO space objects and the associated SNR models. This paper derives an expression for the return signal detected by a coherent ISAL system. Using tomographic techniques common to synthetic aperture radar SAR, a model is developed for the signal-to-noise ratio of the reconstructed image. Noise sources considered include photon noise and laser speckle noise.