An Algorithmic Study on Free-gyro Positioning System( I ) - Measuring Nadir Angle by using the Motion Rate of a Spin Axis -

Jeong, Tae-Gweon; Park, Sok-Chu

Journal of Navigation and Port Research 2007;31(7):751-757.
Published online September 30, 2007.

An Algorithmic Study on Free-gyro Positioning System( I ) - Measuring Nadir Angle by using the Motion Rate of a Spin Axis -

Tae-Gweon Jeong, Sok-Chu Park

Abstract

The authors aim to establish the theory necessary for developing free gyro positioning system and focus on measuring the nadir angle by using the motion rate of a free gyro. The azimuth of a gyro uector from the North can be given by using the property of the free 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 of the spin axis in the NED frame. The component has to be transformed into the horizontal component of the gyro by using the azimuth of the gyro vector and then has to be integrated over the sampling interval

Key Words: Free gyro;Gyro vector;Nadir angle;Angular velocity of the earth's rotation; Motion rate of spin axis;Gyro frame;Platform frame;NED navigation frame