scholarly journals Development of noise correction method of environmental magnetic field with reference magnetic sensor for magnetocardiography

2020 ◽  
Vol 103 (8) ◽  
pp. 21-28
Author(s):  
Kuniomi Ogata ◽  
Akihiko Kandori
Keyword(s):  
Magnetic Field ◽  
Correction Method ◽  
Magnetic Sensor ◽  
Noise Correction

scholarly journals Automotive antenna diversity system for satellite radio with high phase accuracy in low SNR-scenarios

2018 ◽  
Vol 10 (5-6) ◽  
pp. 578-586 ◽  
Author(s):  
Simon Senega ◽  
Ali Nassar ◽  
Stefan Lindenmeier
Keyword(s):  
Signal To Noise Ratio ◽  
A Priori ◽  
Multipath Fading ◽  
Correction Method ◽  
Antenna System ◽  
Antenna Diversity ◽  
Phase Detection ◽  
Low Snr ◽  
Single Antenna ◽  
Noise Correction

AbstractFor a fast scan-phase satellite radio antenna diversity system a noise correction method is presented for a significant improvement of audio availability at low signal-to-noise ratio (SNR) conditions. An error analysis of the level and phase detection within the diversity system in the presence of noise leads to a correction method based on a priori knowledge of the system's noise floor. This method is described and applied in a hardware example of a satellite digital audio radio services antenna diversity circuit for fast fading conditions. Test drives, which have been performed in real fading scenarios, are described and results are analyzed statistically. Simulations of the scan-phase antenna diversity system show higher signal amplitudes and availabilities. Measurement results of dislocated antennas as well as of a diversity antenna set on a single mounting position are presented. A comparison of a diversity system with noise correction, the same system without noise correction, and a single antenna system with each other is performed. Using this new method in fast multipath fading driving scenarios underneath dense foliage with a low SNR of the antenna signals, a reduction in audio mute time by one order of magnitude compared with single antenna systems is achieved with the diversity system.

scholarly journals Magnetic Target Position Estimation Method Based on Prior Information

2021 ◽  
Vol 2113 (1) ◽  
pp. 012020
Author(s):  
Guangfa Sun
Keyword(s):  
Magnetic Field ◽  
Target Recognition ◽  
A Priori ◽  
Magnetic Sensor ◽  
Test Method ◽  
Target Area ◽  
A Priori Information ◽  
Measurement Results ◽  
Magnetic Target ◽  
Priori Information

Abstract Aiming at the problem of detection and location of magnetic targets in water beach, the acoustic magnetic composite detection method is studied. After the sonar obtains the image of the suspicious object in the target area, the magnetic target recognition and location are realized by using the abnormal magnetic field distribution data near the target area measured by the shipborne magnetic sensor and the multi-sensor information fusion method. A target recognition and location method based on a priori information is proposed to solve the problem that the measurement results of magnetic sensor can not fully reflect the influence of ferromagnetic target on the surrounding magnetic field due to terrain constraints. In order to make up for this lack of information, taking the sonar measurement results as a priori information, the hypothesis test method is adopted to make full use of all the measurement results of different types of sensors to realize the recognition and positioning of magnetic targets.

Topographic Correction for the Data of SQUID-based TEM Using a Ground Loop

2019 ◽  
Vol 24 (1) ◽  
pp. 111-117
Author(s):  
Yanju Ji ◽  
Yi Zhao ◽  
Shangyu Du ◽  
Dongsheng Li ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Interference ◽  
Low Frequency ◽  
High Sensitivity ◽  
Absolute Error ◽  
Correction Method ◽  
Topographic Effects ◽  
Topographic Correction ◽  
Transient Electromagnetic ◽  
Ground Loop

Superconducting quantum interference device (SQUID) can be used to detect the signal of transient electromagnetic method (TEM) due to its superiority of high sensitivity in the low frequency range. However, the measuring direction of SQUID is hardly consistent with the normal direction of the transmitting coil of a TEM system because of the undulating topography in the field. In this case, the central magnetic field measured by SQUID is only a component of the theoretical central magnetic field. There will be larger errors if we directly use the measured central magnetic field for geological interpretation. To solve this problem, we propose a topographic correction method for the data of SQUID-based TEM using ground loop. The theoretical central magnetic field of the ground loop is calculated after the trapezoidal transmitting current wave is turned off. Then, we use the theoretical central magnetic field of the ground loop as the reference to correct the measured central magnetic field of SQUID-based on the trigonometric function relation between the measuring direction of SQUID and the topographic inclination. The experiment of SQUID-based TEM using a ground loop was carried out in the field. The result shows that at the measurement point with larger topographic inclination, the average absolute error of the measured central magnetic field reduces significantly with the proposed correction method. This method can also be applied to the correction of complex topographic effects when using SQUID to measure three components of magnetic field.

Application of a HTS Coil With a Magnetic Sensor to Nondestructive Testing Using a Low-Frequency Magnetic Field

2017 ◽  
Vol 27 (4) ◽  
pp. 1-4 ◽  
Author(s):  
Yasuaki Matsunaga ◽  
Ryota Isshiki ◽  
Yuta Nakamura ◽  
Kenji Sakai ◽  
Toshihiko Kiwa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nondestructive Testing ◽  
Low Frequency ◽  
Magnetic Sensor ◽  
Frequency Magnetic Field
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