A HIGH-ACCURACY TIMING METHOD FOR PHOTOGRAPHIC TRACKING SATELLITE——AN IMPROVEMENT IN THE SBG TIMING SYSTEM

A new timing method for a tracking system using a moving plate carriage, is describedin this paper. Bh attaching a digital displacement measuring device to the plate carriage, thevalue of each displacement Sis sampled by a microcomputer at a certain time tand proc-essed along with tto obtain the exposure time of the tracking dot with an estimation ofhigh accuracy. The result shows that the new timing system accuracy is 0.04ms and withoutlag. In addition, we have investigated the original timing system of the SBG thoroughly usingthe new timing system of bigher accuracy. We have found that the original timing systemof SBG had a lag of 2.3ms and its timing accuracy was about 1 ms.