Simulation of a Fourier telescopy imaging system for objects in low Earth orbit

Abstract

Software has been developed for the SAINT program that simulates the operation of a Fourier Telescopy imaging system that could potentially be used to create images of a satellite in low earth orbit. Fourier telescopy uses multiple beams that illuminate the target with a fringe pattern that sweeps across it due to frequency differences between beams. In this way the target spatial frequency components are encoded in the temporal signal that is reflected from the target. The software simulates the propagation effects and target interaction effects that would be present in a real system. This enables the creation of a simulated received signal as a function of time. A particular problem was accurately modeling the appearance of the target as its aspect changes during a rapid transit over the transmitter and receiver. A novel reconstructor has been developed that compensates for atmospheric phase fluctuations affecting the large number of beams transmitted simultaneously( ~10). The reconstructor solves for hundreds of image Fourier components simultaneously, permitting rapid reconstruction of the image.

High-resolution imaging techniques based on optical synthetic aperture

“…Holmes described the technique of Fourier telescopy in detail 10 . Nowadays much of the analysis has been performed on Fourier telescopy [11][12][13][14][15][16] . In this technique, an object is illuminated by several laser apertures, and the interference fringes modulated the object reflectivity.…”

A 37 mJ, 100 Hz, high energy single frequency oscillator*

“…Single-frequency Nd:YAG laser has a wide range of applications, as optical metrology, high-resolution spectroscopy, coherent detection, [1][2][3][4][5][6][7][8] and especially Fouriertelescopy (FT). [9][10][11][12][13][14][15][16][17][18] To obtain a single-frequency laser, three problems need to be solved, including single longitudinal mode selection, single transverse mode selection, and energy enhancement. For single longitudinal mode selection, several ways have been developed, such as short cavity configuration, [19][20][21][22][23] microchip lasers, [23,24] non-planar ring oscillator, [25][26][27][28][29][30] traveling-wave cavity, [31][32][33][34][35][36][37][38][39] twisting mode lasers, and inserted multi etalons.…”

Compressed sensing sparse reconstruction for coherent field imaging

“…It has therefore drawn considerable attention in recent years, becoming a promising candidate in the field of space surveillance and object recognition. [5,6] Based on the computational imaging principle, coherent field imaging can produce good images from the target spatial frequency components encoded in the temporal signal reflected from the target, therefore return signal processing and reconstruction is essentially significant in the whole imaging system. By fine recovery and reconstruction of the return signal, the target image can be obtained with high resolution.…”