The Design Of The Missile-Borne Three-axis Magnetic Measurement System And The Research Of The Magnetic Measurement System Error Calibration And Compensation Method

Modern warfare requires conventional weapons to have the ability of accurately strikingon the target, so precision-guided ammunition plays an important role in the war. The accuratemeasurement data of the magnetic field vector can provide GPS, inertial navigation systemsin conventional weapons with aided navigation data, thereby improve the accuracy ofconventional weapons’guidance. The main contents in this paper is that obtaining thethree-component magnetic field intensity data by designing and developing the missile-bornethree-axis magnetic measurement system and improving the measurement accuracy of themagnetic measurement system by the analysis of the three-axis magnetic measurement systemerror and the missile body’s magnetic field error, thereby providing the integrated navigationsystems in conventional weapons with the accurate geomagnetic aided navigation data. It is ofgreat significance to improve the level of China’s weapons and equipment.For the accurate measurement requirements in the high impact, high speed rotation testenvironment of the conventional ammunition, the sensors, analog components and digitalcomponents were selected by analyzing the requirement of the missile-borne environment.This paper also designed the missile-borne three-axis magnetic measurement system with thesmall volume, low-power, high-precision, high sampling rate, and the ability of multi-channelsynchronous acquisition and the supporting PC software.In the research of the three-axis magnetic sensor error, the model of the sensor’s biaserror, sensitivity error and triaxial nonorthogonal error were established by the analysis of theerrors. Then the ellipsoid fitting algorithm based on the least squares method was selected tocalibrate the sensor’s error coefficient according to the characteristics of the measurement data of which the actual three-axis magnetic sensor measured the same geomagnetic vector ina different posture, thereby determine the three-axis magnetic sensor error calibrationcompensation method. In the research of the misalignment error between the ideal three-axismagnetic sensor and the coordinate of the magnetic measurement system packaging shell, thecalibration compensation model of the misalignment error was established by the analysis ofthe misalignment error between the ideal three-axis magnetic sensor and the coordinate of themagnetic measurement system packaging shell. This paper excogitated a simple misalignmenterror calibration method which doesn’t need the high accuracy calibration equipment,according to the characteristics of the measurement data of which the magnetic measurementsystem measured the same geomagnetic vector in a different posture in the magneticmeasurement system coordinate.In the research of missile body magnetic field, this paper analyzed the effect of themeasurement data of the missile-borne three-axis magnetic measurement system in the fixedmagnetic field generated by the hard iron materials and the induced magnetic field generatedby the soft iron materials in the missile body materials. The mathematical model of themagnetic measurement data affected by the missile body magnetic field was established bythe analysis of the generation mechanism of the fixed magnetic field and the inducedmagnetic field in the missile body materials. The error calibration compensation algorithmwas designed according to the number and the characteristics of the missile body magneticfield error coefficients in the mathematical model.Finally, A series of computer simulations and experiments with test data ware done forverifying the effectiveness of the missile-borne three-axis magnetic measurement system, thecalibration method of the magnetic measurement system error and the calibration method ofthe missile body magnetic field error.