Azimuth-Keeping Characteristic Analysis and Computer Simulation for a Dynamically Tuned Gyro Based North-Finder
A characteristic of a north-finder applied in our project is that in experiments, its azimuth-keeping accuracy and the initial azimuth of the body on which the north-finder is fixed has a relation of the period function whose period is 180 degree. To find what causes this characteristic, the paper firstly introduces the principle of the dynamically tuned gyro based north-finder, then derives the differential equation about the influence of gyro drift upon the north-finder's azimuth-keeping accuracy. Based on this differential equation, several simulations are carried out to study how different sort of gyro drift influences the north-finder's azimuth-keeping accuracy. The comparisons of the simulation results with the experimental ones indicate that the gyro drift results in this characteristic. Ω is the axial rotation angular rate of the Earth along the Up (the local vertical) and it equals sin ie ω φ : ie ω is the axial rotation angular rate of the Earth and φ is the north-finder's latitude. This compensation scheme is rational because the north-finder is used in plain areas, and it is proved feasible by road test of the vehicle.