Heki, K., Three approaches to improve the estimation accuracies of the vertical VLBI station positions

J. Geod. Soc. Japan, 36, 143-154, 1990.

通信総合(旧電波)研究所の所内談話会で行った、「間違いだらけのスケジュール選び」、 「究極のパラメータ推定」、「大気マッピング関数について」という三題噺を論文化した もの。大気マッピング関数の改良で上下位置の系統誤差を減らし、低仰角観測で大気と上下位 置の分離性を向上させ、連続性の拘束を入れて安定化を図った天頂遅延の高時間分解能推定に よって残差を減らす、という上下位置の推定精度の向上の三指針を示した内容。その後のGPS 気象学のコンセプトのひとつ「測地精度の向上」を先取りしていたかもしれない。

It has been pointed out that very long baseline interferometry (VLBI) is less accurate in determining the station positions in a vertical axis than in a horizontal plane. However, possible applications of VLBI for sea level monitoring, terrestrial reference frame for astrometry and earth rotation studies, etc., require accurate determination of the station position in the vertical axis as well as in the other axes. I propose three different approaches to improve the accuracies of the estimated vertical site positions, that is, to control the vertical elongation of the positional error ellipsoids by low elevation observations, to reduce the size of the ellipsoids by decreasing the residuals, and to select a "right" atmospheric mapping function to avoid systematic errors in vertical positions.


日置幸介 (email: heki@ep.sci.hokudai.ac.jp)