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Volume 35 (1989)
- Issue 4 Pages 371-
- Issue 3 Pages 287-
- Issue 2 Pages 63-
- Issue 1 Pages 1-
Volume 35, Issue 3
Displaying 1-9 of 9 articles from this issue
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Takehisa HARADA1989 Volume 35 Issue 3 Pages 287-297
Published: November 25, 1989
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSLet Bx=r be normal equation in adjustment of a huge geodetic network, which has observations of distances but no observation of azimuth, here xT is (3). If the network is so-called a free network which has no point with known position, defect of rank of B is numerically 3 in net-adjustment by means of the method of free -network solution on an ellipsoid. The network can obviously freely move in east -westward but can slightly move in north-southward and rotationally in both narrow limited widths on account of geometric ununiformity of the surface of ellipsoid and limited figures in computation. If we neglect the limited narrow free widths as compared with vast surface of the earth, degrees of freedom of the network is clearly less than 3, however, it is erroneous that we judge the less degrees of freedom is straightly equal to defect of rank of B in net-adjustment. Infinite solutions also numerically exist in the very narrow free widths, because net-adjustment finds out always essentially infinitesimal movement and rotation of the network . We cannot obtain numerically right solution unless defects of rank is 3 at least in the method using generalized inverse matrix with the type of least norm, because the 3 defects just work to halt the above movement and rotation of the network to choose only one solution from infinite ones .View full abstractDownload PDF (1528K) -
Yoichi FUKUDA1989 Volume 35 Issue 3 Pages 299-305
Published: November 25, 1989
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSA new method of Eötvös correction for the surface ship gravimetry is proposed . Since Eotvos correction is calculated from ship's velocity relative to the ground, an essential problem arises from errors of ship's position . To obtain an improved and smooth track of a ship from the given data: ship's velocity relative to the water, ship's heading and NNSS positioning with consideration of its error, reduces to a kind of curve fitting problem which can be effectively solved using the Bayes type discretet spline function.View full abstractDownload PDF (627K) -
—Yasutomi.Usuzuku Baseline Network, Yamasaki Fault, Southwest Japan—Makoto OMURA, Kunio FUJIMORI, Yutaka TANAKA, Shigeaki OTSUKA1989 Volume 35 Issue 3 Pages 307-317
Published: November 25, 1989
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSElectro-optical distance measurements were performed by using a Geomensor CR204 on November 1988 in a small geodetic network, Yasutomi-Usuzuku Baseline Network, across the Yamasaki fault, Southwest Japan. Based on data obtained through the field measurements, characteristics and measurement accuracy of the Geomensor have been discussed in the present article. Prism constants were determined by comparing distances measured by the Geomensor with those by two invar baseline tapes, and their standard deviations were estimated to about 0.1 mm. Distance errors depending on elevation angles of the Geomensor were also found, and then we applied an empirical formula to correct the measured distances. The formula is Lc=Lg+3.1 tanΘ+Cn, where Lc is the corrected distance, Lg the measured distance, Θ the elevation angle of the Geomensor and C, the constant of the prism employed. Most of the data, which were not disturbed by meteorological influences, had discrepancies of less than 0.4 mm at distances ranging from 25 to 340 m, if the formula was applied. The baseline lengths were calculated by applying the least squares method (free network). Standard deviations of the lengths determined were ±0.2 mm, which was equivalent to the strain of ±1×10-6 in the network. The accuracy attained was high enough to detect the crustal strain changes in the network over a period of a few years.View full abstractDownload PDF (1083K) -
Yukio HAGIWARA1989 Volume 35 Issue 3 Pages 319-324
Published: November 25, 1989
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSAs well known the Newtonian gravitational force is governed by the inverse square law of mass separations. In recent years a hypothesis has appeared that, in addition to the conventional Newtonian gravity, there exists another force acting only in the near-field. It is expected on theoretical grounds that the force has a mathematical form similar to the Yukawa-type potential . Our interest is in contributions of the non-Newtonian gravity field to the shape of the geoid . The present paper introduces a theoretical approach to physical geodesy, in which the Yukawa-type potential term is considered. In conclusion we prove the geoid height is hardly affected by the non-Newtonian term.View full abstractDownload PDF (472K) -
Yukio HAGIWARA1989 Volume 35 Issue 3 Pages 325-333
Published: November 25, 1989
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSRecently the non-Newtonian gravitational law has been reexamined on the basis of the theory of elementary particles. An additional force to the conventional Newtonian force is considered to decrease exponentially with a distance between two masses. Some experiments have been proposed for confirming the non-Newtonian behavior of gravity field. The present paper reviews the proposed methods for determining parameters of the exponential term, and moreover suggests a new experimental approach by gravity surveying over an underground fluid reservoir. This new method involves measurements of gravity field change on three horizontal planes before and after fluid injection.View full abstractDownload PDF (4636K) -
Tsuneji RIKITAKE1989 Volume 35 Issue 3 Pages 335-347
Published: November 25, 1989
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA method of potential analysis by use of Hermite functions is worked out in relation to geomagnetic and gravity anomaly. A potential field on a plane surface is expressed with a series of orthogonal functions involving Hermite functions. The coefficients of the series are useful for estimating potential values at different levels in height. The method is especially useful when it is applied to a problem of isolated anomaly because the functions involved tend to become zero at points distant from the anomaly. In actual problems, a number of infinite integrals, which involve Hermite functions, are to be evaluated for specified sets of coordinates. Such numerical integrations can readily be performed fairly accurately because the orthogonal functions tend to vanish very quickly for a large value of distance from the center of the anomaly. Two- and three-dimensional analyses are given in the paper taking the magnetic anomaly at Kursk, that over a magnetized cone and that over Izu-Oshima Island, an active volcano about 110 km southwest of Tokyo, as examples. It is demonstrated that upward continuation of the anomaly is successfully completed for these cases.View full abstractDownload PDF (903K) -
Masao KOMAZAWA1989 Volume 35 Issue 3 Pages 349-351
Published: November 25, 1989
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSGravity value observed below sea level is transformed into gravity (g') in the reduction sphere by filling free space between underwater station and sea level (datum surface) with rock material and by removing rock material from outer area of reduction sphere through terrain correction and spherical Bouguer correction. Normal gravity field (r') below sea level is calculated through free air reduction and subtraction of spherical shell between underwater station and sea level. Since gravity anomaly is defined as "g'-rit is regarded as the value at the station below sea level rather than at the sea surface.View full abstractDownload PDF (1721K) -
[in Japanese]1989 Volume 35 Issue 3 Pages 353-357
Published: November 25, 1989
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (732K) -
[in Japanese]1989 Volume 35 Issue 3 Pages 359
Published: November 25, 1989
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (111K)
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