Mechanical Asymmetry
Rotational rate errors resulting from linear acceleration typically emerge in gyroscopic instruments due to mechanical asymmetries or mass center displacements. The g-sensitive drift defines the degree to which a gyro output changes when subjected to a force acting along its sensing or input axes. The parameter is critical for instruments operating in high dynamic environments where maneuvering forces exceed the local gravity vector.
Acceleration Sensitivity
Mass imbalances within the rotating or vibrating structure of the sensor create torques that the electronics interpret as rotation. Practitioners measure g-sensitive drift by placing the gyro in different orientations relative to gravity or by using a centrifuge to apply sustained linear loads. The resulting error is typically expressed in degrees per hour per g of acceleration.
Because this effect is often linear, a first order coefficient can describe the relationship between the applied force and the induced rate error. Multi-axis testing ensures that sensitivities along the orthogonal axes are captured for the total error budget of the system.
Calibration Routine
Testing procedures often involve a multipoint tumble test where the sensor is rotated through 360 degrees in discrete steps. By analyzing the output at each position, the g-sensitive drift component can be separated from the fixed bias and the scale factor error. This separation allows for the creation of a compensation matrix that subtracts the predicted drift based on the current accelerometer readings.
Installation Constraint
Mechanical stress from the mounting interface can distort the sensor frame and exacerbate these internal imbalances. Proper torque specifications for mounting bolts and the use of stress-relieved materials help maintain the factory calibration of the g-sensitive drift.
