An Algorithmic Study on Free-gyro Positioning System (Ⅰ)

Abstract

The authors aim to establish the theory necessary for developing free gyro positioning system and focus on measuring the nadirangle by using the motion rate of a free gyro. The azimuth of a gyro vector from the North can be given by using the property of thefree gyro. The motion rate of the spin axis in the gyro frame is transformed into the platform frame and again into the NED(north-east-down) navigation frame. The nadir angle of a gyro vector is obtained by using the North components of the motion rate ofthe spin axis in the NED frame. The component has to be transformed into the horizontal component of the gyro by using the azimuthof the gyro vector and then has to be integrated over the sampling interval