Experimental Study on the Localization of Moving Object by Total Geomagnetic Field

Kang, Chong; Fan, Liming; Zheng, Quan; Kang, Xiyuan; Zhou, Jian; Zhang, Xiaojun

doi:10.1155/2017/7948930

Cited by 6 publications

(3 citation statements)

References 14 publications

(21 reference statements)

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“…Though the utility of these methods should not be understated, they nonetheless present a challenge in some mobile contexts. Recent foundational work has shown the ability to compensate for disturbance fields using a magnetometer array [28], but this compensation introduces additional delay to latencies already unsuitable for high-bandwidth tracking of multiple magnets.…”

Section: Introductionmentioning

confidence: 99%

Low-Latency Tracking of Multiple Permanent Magnets

2019

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Magnetic target tracking is a low-cost, portable, and passive method for tracking materials wherein magnets are physically attached or embedded without the need for line of sight. Traditional magnet tracking techniques use optimization algorithms to determine the positions and orientations of permanent magnets from magnetic field measurements. However, such techniques are constrained by high latencies, primarily due to the numerical calculation of the gradient. In this study, we derive the analytic gradient for multiple-magnet tracking and show a dramatic reduction in tracking latency. We design a physical system comprising an array of magnetometers and one or more spherical magnets. To validate the performance of our tracking algorithm, we compare the magnet tracking estimates with state-of-the-art motion capture measurements for each of four distinct magnet sizes. We find comparable position and orientation errors to state-of-the-art magnet tracking, but demonstrate increased maximum bandwidths of 336%, 525%, 635%, and 773% for the simultaneous tracking of 1, 2, 3, and 4 magnets, respectively. We further show that it is possible to extend the analytic gradient to account for disturbance fields, and we demonstrate the simultaneous tracking of 1 to 4 magnets with disturbance compensation. These findings extend the use of magnetic target tracking to high-speed, real-time applications requiring the tracking of one or more targets without the constraint of a fixed magnetometer array. This advancement enables applications such as low-latency augmented and virtual reality interaction, volitional or reflexive control of prostheses and exoskeletons, and simplified multi-degree-of-freedom magnetic levitation.

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Section: Introductionmentioning

confidence: 99%

Low-Latency Tracking of Multiple Permanent Magnets

2019

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“…When the hard magnetic field is small and the induced magnetic field is the main component, the orientation of the target’s magnetic moment is parallel to the orientation of the geomagnetic field. In practice, the induced magnetic field is much larger than the hard magnetic field 18 . In this study, the induced magnetic field is only considered.…”

Section: Resultsmentioning

confidence: 99%

“…But the accuracy of the location is intrinsically limited by the PSO optimization algorithm. Kang 18 presented a method of locating a magnetic diploe based on a scalar magnetometer array. In the method, a conjugate gradient algorithm was designed and the main idea is that the moving target is measured twice with a time interval, thus, the influence of locating target can be eliminated which is caused by the geomagnetic total field with time-varying and uneven spatial distribution.…”

Section: Introductionmentioning

confidence: 99%

A method for estimating magnetic target location by employing total field and its gradients data

You

et al. 2022

Sci Rep

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In this paper, we present a magnetic target localization method by measurement of total field and its spatial gradients. We deduce an approximate formula of the target’s bearing vector expressed by the total field and its gradients. The total field and its gradient can be measured by a scalar magnetometer array and the approximate value of the bearing vector can be calculated. An iterative method is introduced to improve the localization accuracy of the magnetic target. Simulations experiments have been done to evaluate the performance of the proposed method. The results show that the relative errors of the bearing vector estimated by the iterative method can be kept below the level of 5%. In addition, when difference root-mean-square (RMS) noise is added to the magnetometers, the relative errors of the bearing vector only vary from 0.8 to 6%, which indicates that the proposed method has a high tolerance to the noise of the magnetometers.

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