Optical gyro encoder tested on the NTT

Werner W. Schroeder; H. Dahlmann; B. Huber; L. Schuessele; H. Zech; Martin Ravensbergen

doi:10.1117/12.221705

25 September 1995 Optical gyro encoder tested on the NTT

Werner W. Schroeder, H. Dahlmann, B. Huber, L. Schuessele, H. Zech, Martin Ravensbergen

Proceedings Volume 2510, Fiber Optic and Laser Sensors XIII; (1995) https://doi.org/10.1117/12.221705
Event: European Symposium on Optics for Environmental and Public Safety, 1995, Munich, Germany

Abstract

The prototype of an optical gyro encoder (OGE) has been successfully tested on the NTT telescope in September '93. The OGE consists of a ring laser gyro and a fiber optic gyro with their input axis parallel. The gyro outptu signals are compensated for earth rotation and misalignment and are subsequently integrated to get the angles. An adaptive digital control loop locks the fiber optic gyro to the laser gyro data. Thus the combined output has the precision of the laser gyro and the low noise of the fiber optic gyro. Specifically, the bias stability is better than 2 X 10^-3 deg/h, the scale factor accuracy better than 1 ppm, the random walk coefficient better than 5 X 10^-4 deg/(root)h and the resolution better than 3 X 10^-4 arcsec. The OGE has been mounted in the altitude and in the azimuthy axis of the telescope. The data were compared with the telescope disk encoder data. The test data show that the pointing accuracy is about 1 arcsec and the tracking accuracy 0.1 arcsec over a time of 30 seconds. This accuracy is sufficient for the very large telescope, for instance.

Citation Download Citation

Werner W. Schroeder, H. Dahlmann, B. Huber, L. Schuessele, H. Zech, and Martin Ravensbergen "Optical gyro encoder tested on the NTT", Proc. SPIE 2510, Fiber Optic and Laser Sensors XIII, (25 September 1995); https://doi.org/10.1117/12.221705

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