Mechanical Oscillation
Mechanical oscillations transmitted from a mounting structure into a sensor assembly generate high frequency noise and potential bias errors. Platform vibration involves the rapid displacement of the sensing element due to engines, rotors, thrusters and structural flexing in the carrier vehicle. The input can mask the actual signal being measured and lead to extensive data degradation if not properly mitigated.
High Frequency
Signal components often exceed the sampling rate of the analog to digital converter, causing aliasing in the output data. When platform vibration occurs at the same frequency as the internal resonant frequency of a micro-gyroscope, it can induce large scale errors or physical damage to the proof mass. Signal processing units use low pass filters to remove these unwanted oscillations before the data enters the navigation algorithm.
The amplitude and spectral density of the noise are monitored to ensure they stay within the operational limits of the sensor.
Passive Isolation
Isolation systems use rubber mounts or wire rope isolators to absorb energy before it reaches the instrument. The components are tuned to provide a cutoff frequency that is much lower than the expected platform vibration frequencies.
Structural Resonance
Members within the sensor housing may amplify specific frequencies through constructive interference. Identifying these harmonics through modal analysis allows designers to stiffen the assembly and shift the resonances away from the typical operating range.
