초록 ▼

By means of a two-axis, electrically restrained gyro with vertical spin axis, North direction is determined from the ratio of the horizontal components of the angular rate of the earth. The gyro is rotatable about a vertical axis into 0°-, 90°-, 180°- and 270°-positions. The signals thus obtained ar

By means of a two-axis, electrically restrained gyro with vertical spin axis, North direction is determined from the ratio of the horizontal components of the angular rate of the earth. The gyro is rotatable about a vertical axis into 0°-, 90°-, 180°- and 270°-positions. The signals thus obtained are stored. A signal processing circuit operating with various differences of these signals and ratios of such differences provides the North deviation unaffected by gyro drift and scale factor error.

대표청구항 ▼

Instrument for the automatic determination of North direction by means of a gyro influenced by the rotation of the earth, wherein (a) the gyro is a two-axis gyro, the spin axis (z) of which is substantially vertical, (b) a position pickoff (30,24) and a torquer (32,36) are provided on each of the tw

Instrument for the automatic determination of North direction by means of a gyro influenced by the rotation of the earth, wherein (a) the gyro is a two-axis gyro, the spin axis (z) of which is substantially vertical, (b) a position pickoff (30,24) and a torquer (32,36) are provided on each of the two mutually perpendicular input axes (x,y) of the gyro, (c) the signal of each position pickoff (30,24) associated with one input axis (x,y) is applied crosswise to the torquer (26,32) of the respective other input axis (y,x) to restrain the gyro electrically with its spin axis (z) to the vertical, (d) the gyro is rotatable by a servomechanism (42) from an initial position (0°-position) through 180°about a vertical axis (ZG) coincident with the spin axis (z) into a 180°-position, and (e) a north deviation computer (FIG. 6) is provided, which comprises (e1) memories (54,58) for storing the two signals supplied to the torquers in the 0°-position, (e2) difference forming means for generating signals representing the difference of signals which are supplied to one or the other torquer (26,32), respectively, in different positions of the gyro determined by the servomechanism (42), and (e3) quotient forming means for forming the quotient of such differences to provide a trigonometric function of the azimuth angle between one input axis of the gyro and North, characterized in that (f) the gyro is rotatable by the servomechanism (42) about the vertical axis (zG) in addition into a 90°-position and into a 270°-position, and (g) the North deviation computer comprises memories (54 to 68) for storing the respective two signals supplied to the torquers in the 180°-position, the 90°-position and the 270°-position, and (h) the quotient forming means (78) form the respective quotient of differences of signals such that (h1) each difference is formed of two signals which are supplied to the same torquer (26,32) in two positions of the gyro angularly spaced by 180°, (h2) the signals which form the difference in the numerator are supplied to the same torquer (26,32) as the signals which form the difference in the denominator of this quotient, and (h3) the difference in the numerator is formed of signals which are associated with positions of the gyro angularly spaced by 90°from those positions of the gyro which are associated with the signals forming the difference in the denominator.