Study on semi-period transit method in north-seeking

摘要

The precision, speed and automatic degree of gyroscope has become more and more important for the modern north-seeking measurement. Traditional north-finding gyroscope system based on transit method needs a whole gyroscope swing period which could not meet the modern measuring need for its long working time. Based on the principle of period Transit method, semi-period Transit method is proposed to improve the north-seeking speed and automatic degree. Semi-period Transit method requires gyroscope cursor to move through the maximal point of velocity, zero point of collimation and point of reversion respectively. Then the essential information to work out the gyroscope sway period and swing can be obtained from the cursor moving track and velocity fitting curve. Thereby the north-seeking result can be gained. When semi-period Transit method is adopted in coarse north-seeking and precise north-seeking by JT - 15 gyroscope, if the gyroscope collimation deviates real north ±1°, ±8′north-seeking uncertainty can be achieved. While if the gyroscope collimation deviates real north ±15′, ±30″north-seeking uncertainty can be achieved. Compared to whole period. Transit method semi-period Transit method only takes about half time to get the result of seeking north, so the north-seeking speed has been boosted remarkably. In addition, collimation doesn't need to be traced by manipulator in north-seeking, which makes the manipulation easier and improves the instrument automatic degree.