Proc. SPIE. 5634, Advanced Sensor Systems and Applications II
KEYWORDS: Digital signal processing, Sensors, Digital filtering, Interference (communication), Signal processing, Gyroscopes, Analog electronics, Digital electronics, Signal detection, Bessel functions
With the development of the technique of the digital signal processor, the using of digital signal processor in the open loop IFOG (interferometric fiber optic gyroscope) signal processing brings a great improvement of the performance of IFOG, especially in the technique of digital filtering, acquisition the values of arcsine and inverse tan function. The traditional way to get the values of inverse tan function is linear interpolation technique in digital signal circuit. This article put forward a new way to acquire the values of inverse tan function, the proportion of the second order Bessel function to the first order Bessel function and the proportion of the fourth order Bessel function to the second order Bessel function by using of the virtue of DSP, high speed of data processing. The fundamental, second and fourth harmonic signals from photoelectrical detector are sampled and demodulated by analog circuit. Then the signals from analog circuit are sampled into DSP by a 24-bit analog-to-digital converter, which is used to improve the dynamical range of the system. Then DSP computes the values mentioned above by polynomial approach. The simulation in Mathematic and Microsoft Visual C++ 6.0 proved that the method of polynomial approach to the functions has higher precision compared to the method of linear interpolation. Meanwhile the designed circuit shows it can meet the demand of real time data process. The tested results of designed circuit prove it has a great improvement in the dynamic range and precision of IFOG.