Improved Towed Airborne Three-Axis Magnetic Gradient Anomalies Navigation

• Published in: IEEE transactions on instrumentation and measurement Vol. 73; pp. 1 - 12
• Main Authors: Xu, Supeng, Jin, Zixiang, Jiang, Guoming, Zhang, Guibin, Liang, Jian, Sun, Wei, Zhang, Lianzhi, Fan, Zhenyu, Dong, Genwang
• Format: Journal Article
• Language: English
• Published: New York IEEE 2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Accuracy; Airborne three-axis magnetic gradient; Aircraft; Aircraft navigation; Algorithms; Anomalies; Contour matching; Diurnal variations; Error correction; geomagnetic navigation; Geomagnetism; Helicopters; Inertial navigation; Interference; internal coincidence accuracy (ICA); Magnetic devices; Magnetic storms; Magnetometers; matching algorithm; Navigation systems; Noise measurement; Position errors; Satellite navigation systems; Three axis
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2023.3336438

Precise geomagnetic navigation of aircraft without GPS can be challenging. However, the low accuracy of traditional magnetic data and the limitations of the existing geomagnetic matching algorithms affect its implementation. We propose a set of strategies to address these issues. First, we designed a towed airborne three-axis magnetic gradient device for measurements, which effectively reduced the influence of geomagnetic diurnal variation, geomagnetic storms, and aircraft interference. Second, we introduced a least-squares correction algorithm to enhance the accuracy of the magnetic data by reducing the heading error resulting from the magnetometer sensor. The algorithm improved the internal coincidence total accuracy (ICTA) from 0.6529 to 0.0186 nT, a remarkable 35-fold increase. Finally, we established a geomagnetic matching navigation algorithm called aeromagnetic gradient iterative closest contour point (AGICCP) for a three-axis gradient field, which corrected the cumulative error of the inertial navigation system (INS) in long-distance navigation. Our simulation experiments demonstrated that AGICCP outperforms the traditional ICCP and vector ICCP (VICCP) algorithms, reducing the position error from 736.96 and 174.70 m, respectively, to 26.73 m. The suggested magnetic gradient device and the proposed algorithms significantly improve the accuracy of geomagnetic navigation. This study provides new insights into precise airborne navigation with great practical significance.