Abstract : Two Bendix LDG 540 gyroscopes were tested at the Central Inertial Guidance Test Facility, 6585th Test Group, Holloman Air Force Base, New Mexico during the period from 30 September 1975 to 22 January 1976. The purpose of the tests was to characterize the gyro output noise signature in the frequency range from .00001 to 10 Hz with the gyro in a quiescent environment. A description of the test item is presented as well as descriptions of the support electronics, test equipment, fixtures, data acquisition system, and test procedures. A complete set of the individual test results are included in the appendices along with the monitored environmental influences of temperature, pad motion, and the gyro wheel supply electronics. The results are presented both in time domain plots, and the frequency domain power spectral density (PSD) plots. Both gyros were sensitive to temperature and wheel current variations. The best low frequency performance was obtained from the second twenty-four hour test on gyro S/N 1.