North Seeker Based On The Vector Modulating Method

Navigation and orientation is to define the parameters of aerocraft, including the attitude and location. The precise measurement norm is the key factor to carry out the accurate location. The gyroscope north-seeker is a high-precision and self-determination inertial instrument base on the strap-down inertial navigation theory. It can provide the intersecting angle between the reference-orientation and the geographic true north-orientation through measuring the ponderance of Earth Rotary Rate(ERR) at the carrier coordinate axes.With the development of the aerospace and aviation science, the requirement for the precision of the north seeker has become increasingly critical, where gyro is the key to improve the precision. Fibre Optic Gyro (FOG) is the component of the common north-seeker, which has many characteristics, like the all-solid structure, high reliability, integration optics parts, low cost and sordid-work condition resistibility. Furthermore, it is fit for the Strap-down navigation installation.The Fast north-seeker is a hotspot issue in the Navigation and orientation field. The traditional north-seekers include: the Two-position Gyro-based north-seeker; The Gyro-multi-place north-seeker. Theoretically,Using low-precision optical-Gyro can't implement the Two-position and multi-place North seeking scheme. So this paper present a bran-new scheme called the VMM(Vector Modulating Method), Using low-precision optical-Gyro design a north-seeker, the precision fluctuate between 0 and 0.5 degree. Accordingly, this paper is organized as follows:According to the Navigation and Modulation-Demodulation principle and the linear system theory, expatiate the VMM in detail. The VMM adopts a mechanical rotation method to modulate the input signal into sine wave before entering the sensor. Because of the features of frequency consistency specialty and superposition of the linear vector sensor, precise response of input signal will be derived by means of demodulation. Base on the above principle, advance the FOG output math expression after modulating.Due to the low-precision FOG, the output signal includes large numbers of...