초록 ▼

A marine gyro compass output is corrected to take account of accelerations acting upon the ship in which it is installed by calculating about once per second a correction capable of expression by differential equations which are solved by numerical methods by taking small but finite time increments

A marine gyro compass output is corrected to take account of accelerations acting upon the ship in which it is installed by calculating about once per second a correction capable of expression by differential equations which are solved by numerical methods by taking small but finite time increments to linearise the equations with regard to time, the current calculated correction factor being applied to correct the gyro compass output many times per second. The corrections can take into account (a) ship north-south acceleration, (b) change in Coriolis acceleration, (c) earth rotation rate and (d) azimuth error for east-west speed. Furthermore, account can be taken of the constant characteristics of the particular gyro compass to be corrected in terms of its tilt limit, its period of damped oscillation, its damping and the characteristics of the compass electrolytic level which determines tilt.

대표청구항 ▼

A method of correcting the output of a marine gyro compass comprising applying a first signal representative of the speed of a ship to a signal processor, applying a second signal to the signal processor representative of the output of a marine gyro compass, producing an output signal being a correc

A method of correcting the output of a marine gyro compass comprising applying a first signal representative of the speed of a ship to a signal processor, applying a second signal to the signal processor representative of the output of a marine gyro compass, producing an output signal being a corrected marine gyro compass output, the corrections being corrections capable of expression by virtue of differential equations and which are solved by numerical method by taking small but finite time increments to linearize the equations with regard to time, the correction factor being updated in this way at regular time intervals, effecting an initial procedure to feed into a semipermanent data store cooperating with the signal processor values corresponding to a limit of measurable tilt in the gyro compass and said output signal is produced by calculating the rate of change of the tilt up to said limit, the tilt when beyond the limit being also calculated, and storing values corresponding to the following in said initial procedure: the damping characteristic in the gyro compass, the period term for the damped oscillations in the gyro compass following movement to a new position, and a function representative of the viscosity of the fluid in the tilt determining mechanism of the gyro compass. A method of correcting the outut of a marine gyro compass having an electrolytic level indicator comprising storing in a signal processor data representative of a limit of measurable tilt in the level indicator, a damping factor (DMP) for the level indicator, a period term (PER) for the level indicator, and a constant (K) being the viscosity characteristic of the electrolytic level indicator, applying a first signal representative of the speed of the ship to the signal processor. applying a second signal to the signal processor representative of the output of the marine gyro compass, and producing an output signal corresponding to the output of the marine gyro compass corrected by a correction factor by taking into account said input data and first and second signals by solving the following differential equations by numerical methods; EDD=-PER.EES-EE.Fcos(LAT)+VE.tan(LAT)/RG EED=-DMP.EES+ED.Fcos(LAT) EESD=K(EE+AN/G-EES) the solving of the equations being effected by taking small but finite time increments to linearize the equations with regard to time, the correction factor used to produce the corrected output signal being updated at regular time intervals, in the above equations the following notation being used: AN; ship north acceleration ED,EDD; azimuth error and error rate EE,EED; tilt and tilt rate EES,EESD; tilt signal and tilt signal rate G; acceleration due to gravity DMP; damping term of the level detector PER; period term of the level detector K; characteristic viscosity of the compass level detector LAT; latitude FFF