Claims
- 1. A system for reducing spacecraft instrument pointing errors caused by instrument-motion-induced spacecraft motion, said system comprising:
- at least one instrument mounted on a spacecraft and disposed to point towards locations external to the spacecraft;
- coupled to each instrument, motive means for changing the pointing direction of the instrument;
- coupled to each motive means, commanding means for commanding motion in the instrument; and
- compensating means for compensating errors in spacecraft motion induced by instrument motion, said compensating means having an output coupled to each of the motive means and an input coupled to each of the commanding means, wherein the compensating means sends to each of the motive means a signal representative of the negative of the spacecraft motion expected as a result of motion in the instruments commanded by the commanding means.
- 2. The system of claim 1 wherein the compensating means comprises an electronic circuit embodying a model of the negative of the dynamics of motion of the spacecraft.
- 3. The system of claim 1 further comprising means for selectively disabling signals emanating from the compensating means, in response to signals sent from the earth.
- 4. The system of claim 1 wherein the spacecraft instruments comprise:
- an imager having a mirror adjustably pointed at the earth by first motive means; and
- a sounder having a mirror adjustably pointed at the earth by second motive means.
- 5. The system of claim 4 wherein:
- the imager and sounder are mounted on a face of a satellite; and
- the first and second motive means each comprise a two-orthogonal-axis gimbal for selectively pointing the mirrors of the imager and sounder, respectively, at locations on the earth.
DESCRIPTION
The invention described herein was made in the performance of work under NASA Contract No. NAS5-29500 and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, as amended (72 Stat. 435; 42 U.S.C. 2457).
US Referenced Citations (10)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2502404 |
Sep 1982 |
FRX |