Abstract
The geomagnetic sensor is a kind of highly sensitive sensor, which is easy to be interfered with by the outside in the process of measurement. To solve this problem, the author uses the least square method to estimate the gain value and sensitivity product value of the amplification circuit of the geomagnetic sensor and explores the solution of the bias voltage of the geomagnetic sensor by using the ellipsoid fitting model. By analyzing the error sources of the geomagnetic sensors in the measurement process, the error compensation model covering various error factors is constructed. All parameters of the error compensation model are obtained by fitting the experimental data of the turntable. After several experiments with different attitude angles, the validity of the compensation model is verified, and the measurement accuracy of the roll angle is improved, which meets the requirements of roll angle measurement.
Highlights
The geomagnetic field is the inherent basic physical field of the earth
After calculating and summarizing the measured data, the geomagnetic intensity error measured by the three axes of the geomagnetic sensor and the geomagnetic intensity error obtained after compensation are shown in Figure 7, in which the dotted line represents the change of geomagnetic intensity error before compensation, and the solid line represents the change of geomagnetic intensity error after compensation
The least square method and ellipsoid fitting model are used to estimate the optimal parameters in the input–output relationship of geomagnetic sensor
Summary
The geomagnetic field is the inherent basic physical field of the earth. Geomagnetic intensity exists at any place in the near-earth space, and the intensity and direction will change with the longitude, latitude, and height, but in a relatively short time and a small space, the difference is not significant.[1,2] Based on the characteristics of the geomagnetic field, the three-axis geomagnetic sensor can measure the projection of geomagnetic vector on the carrier coordinate system, so as to obtain the attitude of the carrier and provide technical support for navigation control. The final goal of sensor calibration is to get more accurate variable L and zero drift value, which can reduce the influence of system error for subsequent attitude test It can be seen from formula 1 that the direct output voltage value of the geomagnetic sensor is a cosine function of the angle between the sensor sensitive axis and the geomagnetic vector. Ax = cos2Icos2(D À b) + sin2I ð7aÞ cos (D À b) lx = arctg tan I ð7bÞ sin a cos (D À b) À tan I cos a lyz = arctg sin (D À b) ð7cÞ qAyzffiffi=ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ( cos I sin a cos (D À b) À sin I cos a)2 + cos2Isin2(D À b) ð7dÞ Another mathematical expression of variable L and zero-drift value can be obtained by taking equation (6) back to equation (2), as shown in the following formula. The non-orthogonal error model shown in the above figure can be expressed as
Sign-in/Register to view highlights & summary 
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call