Research Of Geomagnetic Navigation Detector And Its Calibration Technology

With the rapid development of navigation, on one hand, digital magnetic orientation equipment has been used in ship navigation because of the low cost, high reliability and high precision. It makes up the shortages of GPS and gyroscopes. On the other hand, traditional single-function navigation equipment can no longer meet the demands of ship's control nowadays. Integrated navigation system based on magnetic orientation will become a new research direction. This paper synthesizes the advantages of the digital compass, digital azimuth instrument and GPS module, and combines them into a geomagnetic navigation detector. It has completed the digital compass design and the high-precision calibration algorithm. This detector can provide information on geomagnetic intensity, magnetic heading angle, attitude angle, target image, latitude and longitude, Green time and so on.The digital compass has been developed successfully as the core navigation module. It consists of a 3-axis magnetic sensor which is produced by Honeywell, a tilt sensor which is produced by ADI, and a dsPIC30F4013 microprocessor which is produced by Microchip. It also comprises a 16-bit A/D converter to amplify and sample the analog signal from the magnetic sensor. A transport protocol is designed to control the output and query the variable.Based on the digital compass, a geomagnetic navigation detector is designed by a dual-core system which is combined a DSP core with an ARM core. It can capture the video from CCD camera, display the video on the TFT monitor after adding a man-machine interface above it, transmission the data among the peripherals, and execute the migration algorithms.In addition, according to the problem from the process of development, the paper puts forward a new calibration method. The calibration based on Single-heading can realize the compass calibration without the need to rotate the ship in a circle movement. In this scheme, the ship magnetism and the earth magnetism are measured separately basing on two hypothesis premises. It has simplified the tedious steps of the traditional self-calibration process.It reduces the cost of navigation equipment by researching the core module. This design plays the advantages of several navigation equipments, and shows a digitized, intelligent and automatic system, and also shows a good prospect.