Space geodesy (English spelling)

Japanese: 宇宙測地 - うちゅうそくち（英語表記）space geodesy

A technology that uses radiation and reflected light from celestial bodies and artificial celestial bodies to precisely measure the distance between two points on Earth, vertical movements, and the distance between the Earth and celestial bodies. GPS receives radio waves from multiple artificial satellites simultaneously to instantly confirm the current position and observe crustal movements and the rise and fall of sea levels. SLR (Satellite Laser Ranging) simultaneously observes artificial satellites from three or more points on the Earth's surface and determines the location of an unknown point by precisely measuring the round-trip time. VLBI (Very Long Baseline Interferometry) receives radio waves from quasars with an accuracy of 0.1 nanoseconds between distant points and precisely determines the distance between those points. Measurements can be made with an accuracy of a few millimeters. In recent years, synthetic aperture radar (SAR) has been used to detect crustal movements.

(Yasuji Saito, Director of the Kanagawa Prefectural Museum of Natural History / 2007)

Source : "Chiezo" published by Asahi Shimbun Publications Co., Ltd. About Chiezo

Japanese:

天体や人工天体からの放射や反射光を利用して、地球の2地点間の距離や上下変動、地球と天体の距離を精密に測定する技術。複数の人工衛星からの電波を同時受信し、現在位置を瞬時に確認、地殻変動や海面の昇降を観測するGPS、人工衛星を地表の3地点以上から同時観測し、往復時間の精密測定から未知の地点位置を決めるSLR(衛星レーザー測距)、クエーサーからの電波を遠く離れた地点間で到達時間差0.1ナノ秒の精度で受信し、その地点間の距離を精密に決めるVLBI(超長基線電波干渉計)などがあり、誤差数mmの精度で測定できる。近年、地殻変動の検出にSAR(synthetic aperture radar:合成開口レーダー)が利用されている。

(斎藤靖二神奈川県立生命の星・地球博物館館長／ 2007年)

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