Magnetic-interference-free dual-electric compass

Lee, KyungMoon; Kim, YangHwan; Yun, JaeMu; Lee, Jang-Myung

doi:10.1016/j.sna.2005.01.032

Cited by 18 publications

(4 citation statements)

References 1 publication

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“…In [25,26], sensor tags are embedded into shoes, which can perceive the user's moving trace. However, the IMU-based approaches are usually vulnerable to magnetic interference, because the electronic compasses can be impacted by magnetic changes [13,23,32]. For example, in [34] it is shown that, the presence of magnetic materials such as metal in buildings can disturb a compass's perception of North, and the direction error of compasses in an office building can be as high as 30 • .…”

Section: Related Workmentioning

confidence: 99%

“…The accelerometers, gyroscopes and compasses in cellphones or Inertial Measurement Units (IMUs) are used to measure the motion of users and thus estimate the walking paths. However, the electronic compasses can be interfered by magnetic field changes [13,23,32], especially for the scenarios where the magnetic field changes significantly [6,38], such as in manufacturing plants [27]. In contrast with the previous approaches, if we use force sensors alone to locate users, the cost of the anchor installation and site survey can be eliminated.…”

Section: Introductionmentioning

confidence: 99%

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ShoesLoc

Jin

Nahrstedt

2019

Proc. ACM Interact. Mob. Wearable Ubiquitous Technol.

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Currently, in-shoe force sensors have been widely used for step counting and gait analysis. However, it has not been realized that in-shoe force sensors are also capable of tracking walking paths. In this paper, we present ShoesLoc, an indoor walking path tracking method based on in-shoe force sensors. We show that, based on the force signals from a user's shoes, it is possible to estimate the walking direction change and the stride length of each step with machine learning techniques. We further apply a particle filter to combine this information with the constraint of barriers in floor maps, and thus can determine the walking path and the current position of the user. To solve the problem of the low accuracy caused by cumulative walking direction errors, we improve the particle filter by designing the direction correction algorithm. Moreover, we propose the weight normalization method to handle the impact of handbags and backpacks. Our experimental results show that, after a convergence phase, ShoesLoc achieves the average location error of 0.9-1.3 m. Compared with traditional indoor tracking technologies, ShoesLoc does not require the installation of wireless anchors, and has good robustness to environment changes such as the magnetic interference. CCS Concepts: • Information systems → Location based services; • Human-centered computing → Ubiquitous and mobile computing systems and tools.

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Section: Related Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

ShoesLoc

Jin

Nahrstedt

2019

Proc. ACM Interact. Mob. Wearable Ubiquitous Technol.

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“…The magnitude of magnetic interference, as well as interference caused by metal reflectors, is unpredictable and cannot be modeled numerically or compensated by calibration. Such external magnetic interference can significantly increase the error of the compass [54][55][56]. Installing a digital compass and global positioning system (GPS) in a solar tracker is economically unprofitable compared to a tracker based on photosensors.…”

Section: Introductionmentioning

confidence: 99%

Optimized Single-Axis Schedule Solar Tracker in Different Weather Conditions

et al. 2020

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Improving the efficiency of solar panels is the main task of solar energy generation. One of the methods is a solar tracking system. One of the most important parameters of tracking systems is a precise orientation to the Sun. In this paper, the performance of single-axis solar trackers based on schedule and light dependent resistor (LDR) photosensors, as well as a stationary photovoltaic installation in various weather conditions, were compared. A comparative analysis of the operation of a manufactured schedule solar tracker and an LDR solar tracker in different weather conditions was performed; in addition, a simple method for determining the rotation angle of a solar tracker based on the encoder was proposed. Finally, the performance of the manufactured solar trackers was calculated, taking into account various weather conditions for one year. The proposed single-axis solar tracker based on schedule showed better results in cloudy and rainy weather conditions. The obtained results can be used for designing solar trackers in areas with a variable climate.

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“…The interferences are classified into three types: time-invariant, high-frequency, and low-frequency interferences. The time-invariant interference is caused by the installation on the metal-structure, which can be compensated by the one-turn rotation scheme [8]. The high-frequency interference is filtered out by a linear estimation algorithm, and the low-frequency interference is eliminated by using the difference between the two compasses.…”

Section: Introductionmentioning

confidence: 99%

Implementation of Spreader Pose Control Using Dual-Electric Compasses

2009

Self Cite

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A spreader pose control system based on the skew angle of the spreader has been implemented by using dual-electric compasses. In the conventional spreader pose control, researchers most often use CCD cameras, laser sensors or tilt sensors to measure the skew angle. However, those sensors are not only sensitive to the weather and disturbances but are also expensive to build a stable system. To overcome these shortcomings, an inexpensive and efficient system to control the spreader pose has been implemented by using dual-magnetic compasses. Note that since the spreader iron-structure itself is a noise source to the magnetic compass, it is not considered prudent to use the magnetic compass to measure the orientation of the spreader. An algorithm to eliminate the interferences of metal structure to the dual compasses has been developed in this paper. To show the effectiveness of the dual-magnetic compasses proposed in this study, a 10:1 reduction model of a spreader control system is implemented and real pose control data are analyzed.

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Magnetic-interference-free dual-electric compass

Cited by 18 publications

References 1 publication

ShoesLoc

ShoesLoc

Optimized Single-Axis Schedule Solar Tracker in Different Weather Conditions

Implementation of Spreader Pose Control Using Dual-Electric Compasses

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