The navigation accuracy of laser strap-down inertial navigation products declines with gyro dither, which is a bottleneck problem for the development of the important aviation instrument. The reason is that the dither of three gyros in the product couples and generates extra noise in the output signals of gyros. To decouple dither, this paper applies the vibration absorber in laser inertial navigation products. First of all, an angular vibration model of the three-rigid body system, which is constructed by the gyro, platform, and vibration absorber, is established. Then, the theoretical restriction of the absorber and the system response are derived. Finally, considering the power limitation for dither, the total power of the vibration system is analyzed. The analytical and experimental results show that the efficiency of the vibration absorber only relates to the frequency offset with gyros, and the absorber does lead to a sharp power increase.

/pdf/the-application-of-the-vibration-absorber-in-laser-inertial-ypjukbsoyh.pdf

The Application of the Vibration Absorber in Laser Inertial Navigation Products

A correcting digital filter for a mechanically dithered single-axis ring laser gyro (RLG) is proposed. The filter is intended to determine the angular position of a strapdown inertial navigation system (SINS) in the RLG sensitivity axis using the known value of the RLG angular position with respect to inertial space, taking into account the models of the suspension elastic forces nonlinearity, the hysteresis model of vibration energy dissipation, and the model of the suspension piezoceramic vibratory drive. Parameterized models of nonlinearity, dissipation, and the output characteristic of the suspension piezoceramic drive have been developed. A method for finding nonlinearity parameters of elastic forces using a set of experimental amplitudefrequency characteristics (AFC) is proposed. Numerical simulations of the AFCs of an elliptic eliminator and a correcting filter under sinusoidal rotation of the SINS with the amplitude of 1 arcmin in the frequency band of 80–3600 Hz have been performed. The efficiency of the proposed filter has been verified experimentally under pulse action on the SINS; the test results are discussed. Comparison of the experimental and calculated data shows the adequacy of the proposed models and satisfactory operation of the correcting digital filter.

A. M. Tolochko

Papers

A correcting filter for a mechanically dithered single-axis ring laser gyro