Vision System With Ranging For Maneuvering In Space

Abstract

Automated rendezvous, stationkeeping, and docking, as well as robot vison for space construction, require a compact, rugged system to provide two-and three-dimensional (range) images. The system proposed in this paper consists of a module having a transmitter array of laser diodes and a single detector/receiver that covers the full field of view (FOV) of the module. Each diode in the array is imaged on a pixel in the FOV. Sinusoidal intensity modulation is used such that the range at each pixel can be determined by phase comparison of the transmitted and received signals. The system FOV can be expanded by using multiple modules. The laser diode modulation frequency is initially low to determine coarse range without ambiguities. It is then increased in sequential steps to reach the desired accuracy for a given range. Because the scanning is accomplished by individually illuminating elements in the diode array, the scanning is achieved with no moving parts, and the pixels in the FOV can be randomly accessed. Preliminary results demonstrated a 15 cm range accuracy with an uncooperative target at a range of 13 m in bright sunlight.