The Design And Implementation Of High-precision Magnetic Compass

When a vessel is navigating at sea,such an alternative navigation device with a moderate accuracy and strong anti-interference capability is required for the magnetic compass.The magnetic compass will encounter a very complicated application environment when it is actually used.The vibration of the carrier and the change of the magnetic environment will bring great errors to the navigation of the magnetic compass.This article analyzes these errors in detail and proposes solutions.Finally designed a high-precision magnetic compass for marine use.First,the principle of calculation of the magnetic heading is analyzed,and the mathematical model of the heading is obtained.Then,in order to improve the accuracy of heading measurement,the measurement error was analyzed.According to the different error mechanism,the error is divided into sensor error,installation error,carrier error,environmental error and magnetic declination.Through the analysis of these errors,a mathematical model of the magnetic compass error was established,which laid a foundation for solving the error.Then,for these different errors,this article focuses on solving carrier error and environmental error.The carrier error causes the magnetic field measurement to be distorted from a circle to an ellipse.In this paper,the ellipsoid fitting method is used to compensate.The environmental error mainly refers to the error caused by eliminating the tape from the hull.This paper uses a time-interval method to solve this problem.In the dynamic state,the carrier inclination angle measurement will have a relatively large error.In response to this situation,simultaneous measurement is performed using a gyro and an accelerometer to improve the dynamic accuracy of the inclination measurement.Based on the above conclusions and the measurement principle of magnetic compass,the calculation formula of magnetic compass after compensation is obtained,and its correctness is verified through simulation experiments.After that,based on this,using the stm32f407vet6 chip as the core,the hardware platform of the magnetic compass was built and an internal software program was designed to realize the data acquisition function,the heading display function,the data transmission function,the magnetic field compensation function,and the human-computer interaction.Features.Finally,a high-precision magnetic compass that can be used on a ship is obtained.Finally,the magnetic compass was verified in the experiment.Firstly,the static accuracy of the magnetic compass was tested on a turntable with an accuracy of 1° or less;then a dynamic test was performed on the cart,with an accuracy of 3°;and finally,a test of the magnetic compass was conducted on the ship,and was obtained.The ideal effect,direct flight accuracy and maneuvering precision have reached the expected requirements.