Gyro noise testing in the low frequency range using PSD analysis

Power spectral density measurements from .00001 to 10 Hz have been made of the output noise of eight inertial gyros from different manufacturers competing for selection as stabilizers for a satellite attitude reference system. Accomplishing this task required substantial instrumentation as well as rapid and flexible data handling. The gyro environment was monitored simultaneously with the gyro output allowing for observation of and compensation for variations in test pad tilt, ambient temperature, gyro temperature, and wheel supply voltage and current. A description of the test station used for the measurements is presented along with representative samples of the monitored environment and noise output of the various gyros. In addition, the interactive computer system built around the Fast Fourier Transform (FFT) is described and the techniques required to perform frequency analysis on long term data are discussed.