Selection of the Geomagnetic Normal Field and Calculation of Geomagnetic Anomalous Field

Gao, Jintian; An, Zhenchang; Gu, Zheng; Han, Wei; Zhan, Zhongwen; Yao, Tong-Qi

doi:10.1002/cjg2.627

Cited by 13 publications

(8 citation statements)

References 14 publications

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“…After adding the calculation values at some IGRF points in the boundary area, the above-mentioned misfit of the geomagnetic anomalies is reduced (Gu et al, 2004;Gao et al, 2005). In order to search for the rationality of the number of the added IGRF points and the distribution, a model calculation is done for some groups of selecting 28∼48 IGRF points and their homogeneous distribution.…”

Section: Discussionmentioning

confidence: 99%

“…In the research on geomagnetic field model in China, Chen (1948) first established the Taylor polynomial model of geomagnetic field in Beipai region of Chongqing for 1946. Chinese scientists have studied the geomagnetic models by using the Taylor polynomial method, the rectangular harmonic analysis, the spline method and the spherical cap harmonic analysis (An et al, 1991;Xia et al, 1988;Xu et al, 2003;Gu et al, 2004;Gao et al, 2005). The above-mentioned results have greatly promoted the development of the research on geomagnetic field model.…”

Section: Introductionmentioning

confidence: 99%

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Geomagnetic survey and geomagnetic model research in China

Zhan

Gao

et al. 2006

Earth Planet Sp

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The geomagnetic survey at 135 stations in China were carried out in 2003. These stations are with better environmental condition and small magnetic field gradient (<5 nT/m). In the field survey, the geomagnetic declination D, the inclination I and the total intensity F were measured. Ashtech ProMark2 differential GPS (Global Positioning System) was used in measuring the azimuth, the longitude, the latitude and the elevation at these stations. The accuracy of the azimuth is 0.1 . The geomagnetic survey data were reduced using the data at geomagnetic observatories in China. The mean standard deviations of the geomagnetic reduced values are: <1.5 nT for F, <0.5 for D and I . Using the geomagnetic data which include the data at 135 stations and 35 observatories in China, and the data at 38 IGRF (International Geomagnetic Reference Field) calculation points in China's adjacent regions, the Taylor polynomial model and the spherical cap harmonic model were calculated for the geomagnetic field in China. The truncation order of the Taylor polynomial model is 5, and its original point is at 36.0• N and 104.5• E. Based on the geomagnetic anomalous values and using the method of spherical cap harmonic (SCH) analysis , the SCH model of the geomagnetic anomalous field was derived. In the SCH model, the pole of the spherical cap is at 36.0• N and 104.5• E, and the half-angle is 30• , the truncation order K = 8 is determined according to the mean square deviation between the model calculation value and the observation value, the AIC (Akaike Information Criterion) and the distribution of geomagnetic field.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geomagnetic survey and geomagnetic model research in China

Zhan

Gao

et al. 2006

Earth Planet Sp

Self Cite

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“…2). The Taylor polynomial model and the spherical cap harmonic model (Haines, 1985;An, 2003;Gu et al, , 2006Gao et al, 2005) of geomagnetic declination in China were established. In calculating the geomagnetic field model, the results appear larger misfit of ge- omagnetic anomalies in the boundary area when only using the geomagnetic data at 135 stations and 35 observatories in China.…”

Section: Analysis and Processing For The Measurement Datamentioning

confidence: 99%

“…In calculating the geomagnetic field model, the results appear larger misfit of ge- omagnetic anomalies in the boundary area when only using the geomagnetic data at 135 stations and 35 observatories in China. After adding the calculation values at some IGRF points in the boundary area, the above-mentioned misfit of geomagnetic anomalies is improved (Gu et al, , 2006Gao et al, 2005). In order to search for the rationality of the number of the added IGRF points and the distribution, a model calculation was done for some groups of selecting 28∼48 IGRF points and the homogeneous distribution.…”

Section: Analysis and Processing For The Measurement Datamentioning

confidence: 99%

Application of GPS in geomagnetic survey

Zhan

Gao

et al. 2006

Earth Planet Sp

Self Cite

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When measuring the geomagnetic declination, the azimuth of the reference mark must be measured. This paper briefly describes the principle of measuring the azimuth by the differential GPS (Global Positioning System), several test observations of GPS and the results. In geomagnetic survey in China during 2002∼2003, GPS was used in measuring the azimuth. Field observations by GPS were carried out during the period that satellite signals were better received. The statistical results of the GPS data at 135 stations in China show that the difference of the azimuths between 2 GPS measurements at various stations is 0.0 ∼5.9 and the average is 1.6 . The azimuthal accuracy measured by GPS in this paper is 0.1 , and it is much better than the azimuthal accuracy 1.0 given by Newitt et al. (1996). The observation results show that the azimuths measured by GPS are accurate and reliable; they are not related to the time-space changes. The geomagnetic declinations D at various stations were obtained based on the azimuths measured by GPS, and the standard deviation of the reduced value of D was < 0.4 . Using the reduced values, the 8-order spherical cap harmonic model and the 5-order Taylor polynomial model in China for D were obtained. In geomagnetic survey, GPS is also used in measuring the longitude, the latitude and the elevation at various stations.

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“…Generally, the effective geomagnetic map described in sea surface or up only reflect the geomagnetic field of detection surface, but can't represent the magnetic anomaly due to geologic structural changes and ferromagnetic object [1][2][3]. In order to automatic geomagnetic localization under water, a solution based on magnetic anomaly is put forward: the magnetic anomaly is inversed a magnetic target position relative to the underwater vehicle, which is determined by measuring magnetic field magnitude and gradient of target , and then the position of the vehicle is achieved by SLAM (simultaneous location and mapping ) algorithm.…”

Section: Introductionmentioning

confidence: 99%

Effect upon vehicle position precision of errors in measuring magnetic field device

Huang

Sun

Ling

2009

2009 9th International Conference on Electronic Measurement &Amp; Instruments

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The relative position between magnetic target and the device, which is installed on vehicle under water, is determined by measuring magnetic field magnitude and its gradient of target on condition that geomagnetic field anomaly can be viewed as a magnetic dipole object. The errors of measuring magnetic field and its gradient caused by nonorthogonality between axes, different sensitivity of each axis, and installation center departure of magnetometers are analyzed in theoretically. These errors of magnetic field magnitude and its gradient can act effect on the localization precision of underwater vehicle, which is analyzed theoretically and simulation numerically. These results show that magnetometer performances such as nonorthogonality between axes, and different sensitivity of each axis have the remarkable influence on the localization precision.

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Selection of the Geomagnetic Normal Field and Calculation of Geomagnetic Anomalous Field

Cited by 13 publications

References 14 publications

Geomagnetic survey and geomagnetic model research in China

Geomagnetic survey and geomagnetic model research in China

Application of GPS in geomagnetic survey

Effect upon vehicle position precision of errors in measuring magnetic field device

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