The Impact of Dynamic Solar Panels on Long Exposure Fourier Telescopy

摘要

Fourier telescopy offers the capability to obtain images of geosynchronous satellites by trading the need for a high power laser and a very large high optical quality receiver for a very large collecting aperture of lower optical quality. The GLINT Program is managed by the US Air Force Research Laboratory and is funded by a congressional add and completion requires continued support. The proposed collector consists of 40 heliostats, each 10m~2. The optical quality of the heliostats is not a major issue as the images are obtained by demodulating a received time-series signal. Even with a 4,000m~2 collector the energy requirements dictate that as many as 200 pulses must be averaged for each triple product to be obtained. With a laser operating at several Hertz, the collection of data for a single triple product will take minutes and the collection of the full set of triplets for a modest system, will take several hours. This paper studies strategies for dealing with dynamic solar panels. During an engagement, the body of the satellite will remain fixed relative to the ground site; however the solar panels will turn to point at the sun. Data collected for a full night will be corrupted. One approach is to take data for a short period over many nights at the same solar time. Examples are presented of image quality versus length of time of data collection. The analysis makes uses of the Air Force Research Laboratory's Time-Domain Analysis and Simulation for Active Tracking (TASAT) code. The amount of time that data may be collected on a given night is compared to the quality of the image recovered. A successful laboratory demonstration of Fourier telescopy is also described.