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Volume 38 (1992)
- Issue 4 Pages 315-
- Issue 3 Pages 211-
- Issue 2 Pages 89-
- Issue 1 Pages 1-
Volume 38, Issue 2
Displaying 1-8 of 8 articles from this issue
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Guangqi CHEN, Teruyuki KATO1992 Volume 38 Issue 2 Pages 89-102
Published: July 25, 1992
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSA method for calculating strain field from repeated GPS observations is presented. It includes three major procedures. At first, the adjustment of a GPS baseline network is carried out. Both the displacements of observation points and the variations of base-, lines in the network are calculated out in this procedure. And then, the whole network is divided into finite uniform grids. The displacements on the grid points are calculated by using an interpolation and extrapolation method. Finally, The principal strains and dilatation in each grid area are calculated from the displacements on its grid points by assuming a uniform strain field within the small grid area. As an example, the strain field in the Sagami Bay from 1989 to 1990 has been calculated.View full abstractDownload PDF (1138K) -
Naosuke SEKIGUCHI1992 Volume 38 Issue 2 Pages 103-112
Published: July 25, 1992
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA possible interpretation is proposed on the anomalous behaviour of the polar wobble around 1930, where the radius of its Chandlerian component was diminished and, in addition, its phase was advanced. This phenomenon is interpreted as a result of statistical fluctuations of the pole due to the random excitation processes. Assuming that the excitation of the polar wobble consists of random motions of the excitation pole with the time scale of a week, we estimate the probability that a remarkable decreaseof the Chandlerian motion occurs within 2-Chandlerian periods. It is found to be quite possible that we can experience such a phenomenon once a century. Numerical simulations suggest that both the phase advance and retardation of the polar wobble will occur with almost equal probability, and the former case took place around 1930 .View full abstractDownload PDF (1304K) -
Arata SENGOKU1992 Volume 38 Issue 2 Pages 113-117
Published: July 25, 1992
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSPrecise and high-speed estimation of perturbation due to geopotential field is essentially important in orbital analyses of near Earth satellites, since perturbation due to geopotential field is much larger than any other perturbations and its estimation is one of the most time-consuming process in the analyses. However, prevalent algorithm has spurious singularity at poles. Here we report a new algorithm to estimate accerelation due to geopotential field at high speed, three times as fast as older ones, without any singularity.View full abstractDownload PDF (526K) -
Ken-ichi NAGASAKA, Yoichiro FUJII1992 Volume 38 Issue 2 Pages 119-135
Published: July 25, 1992
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSWe can deduce the three-dimensional baseline vectors ref ering to the geocentric rectangular coordinate with GPS interferometry. We developed the free adjustment technique that make use of the observed three-dimensional baseline vectors in GPS network.
The free adjustment can be performed with aid of pseudo-inverse matrix N+ that is equivalent to solve the normal equation under the constraint equation Σ(ΔXi)=o(i=1-k), where ΔXi is the estimated correction values for the initial coordinates of GPS stations and k is the number of GPS stations. Then we can also estimate the confidence ellipsoid that indicates the errors of the coordinates at the GPS stations with the elements of variance-covariance matrix.
We apply the developed free adjustment to the results of GPS survey in the Boso Peninsula, Japan. This Boso GPS campaigns had been in operation during 25-28 October 1990 and the occupied stations were six points (Mito, Itako, Yayoi, Chiba, Chosi, Kominato). The observation scenario was divided into two sessions that are assigned asSession-1 (08:0010:00 UT) and the Session-2 (10:00-12:00 UT).
Standard deviations of the adjusted coordinates at the GPS stations range from 1.70 cm to 2.48 cm for the Boso GPS campaigns of the observation at the Session-1 in 27 October 1990, while at the Session-2 of the same day, standard deviations of the coordinates range from 8.73 cm to 10.49 cm. As compared the precision for the observation at the Session-1 with at the Session-2, it is clear that the precision for the observation at the Session-2 is inferior to the one at the Session-1. The cause of the difference of the precision mainly depends on the difference of the satellite configurations.
It is suggested that the direction of semimajor axis, the shape and the size of confidence ellipsoid are much affected by the GPS satellite configurations.View full abstractDownload PDF (1725K) -
M. MURATA, T. TSUJII, K. MATSUSHIMA, T. ONO, Y. MIYAZAWA, K. ISHIKAWA, ...1992 Volume 38 Issue 2 Pages 137-149
Published: July 25, 1992
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSFlight experiments have been conducted at the Sendai airport using the experimental research aircraft Dornier-228-200 (Do-228) of National Aerospace Laboratory (NAL). The objective is to evaluate new navigation sensor technologies which will play a key role in the design of HOPE (H-II Orbiting Plane) approach/landing (A/L) navigation system. The navigation sensors tested include Microwave Landing System (MLS), Global Positioning System (GPS), Inertial Navigation System (INS), and radar altimeter. Differential GPS (DGPS) is also tested in both standalone and hybrid modes. During the flight the Do-228 is tracked by a laser tracker. Tracker data are used to provide reference trajectories of the aircraft. Navigation accuracy is evaluated as the difference between reference trajectory and navigation output from respective navigation sensors or hybrid systems in the post-flight analysis. This comparison becomes possible if we could establish a, common reference navigation frame on which all navigation outputs are transformed. Since GPS provides absolute position and velocity with respect to the World Geodetic System 1984 (WGS84), while others generally provide relative position (and velocity) information, it is convenient that such a navigation frame is referenced to the WGS84 system. In this paper, a method based on GPS surveying is proposed and applied to establish such a reference frame and position coordinates of the groundbased navigation-aid facilities. An example of application of the surveying results is presented which evaluates standalone GPS navigation accuracy for the A/L flight phase.View full abstractDownload PDF (1267K) -
Katuo SETA, Shigeo IWASAKI, Barry K. WARD, Tadanao O'ISHI1992 Volume 38 Issue 2 Pages 151-162
Published: July 25, 1992
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA baseline consisting of seven base points was set in an underground tunnel at the National Research Laboratory of Metrology, in order to calibrate EDMs with high accuracy. These base points are located on a straight line to supply twenty-one distances ranging from 9 to 190 m to estimate cyclic error. Each distance is measured by means of a quasi white light interferometer, its light source is a multi-mode laser diode, with an error of less than 30pm±0.1 ppm. Most commercially produced EDMs can be calibrated on this baseline with an accuracy required.View full abstractDownload PDF (1207K) -
Harumi AOKI1992 Volume 38 Issue 2 Pages 163-166
Published: July 25, 1992
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe accuracy of crustal strain measurement and its dependence on distance are illustrated on a figure for various instruments to demonstrate the detection capability of crustal strain.View full abstractDownload PDF (550K) -
Teruyuki KATO, Shujiro NISHI1992 Volume 38 Issue 2 Pages 167-169
Published: July 25, 1992
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (255K)
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