the gravity recovery and climate experiment (grace), twin satellites launched in march 2002, are making detailed measurements of the earth's gravity field. it will yield discoveries about gravity and the earth's natural systems. different sensors and instruments have been placed in the grace satellites to fulfill the primary scientific objective of the mission in mapping the earth’s g...

gravity recovery and climate experiment (grace) satellite gravimetry mission launched in march 2002 based on its twin gravimetric satellites makes application of both high-low (hl) and law-low (ll) gravimetric techniques possible. the ll is based on satellite-to-satellite tracking (sst) via the one way two frequencies k-band-ranging between the two grace satellites. as a result of combination o...

one of the most valuable and important application of artificial satellites in geodetic sciences is recovery of the earth's gravity field. orbits of satellites either gravimetric or nongravimetric are analyzed to improve the earth's gravity field. gravimetric satellites are launched at low altitudes to observe gravity field in more detail. grace twin satellites are the second spacecra...

Spacecraft formation flying has received significant attention over the past decade, it has been a topic of interest because of its unique technical advantages and good application features. Several small, unconnected satellites operating in a coordinated way may achieve a better performance than a monolithic satellite, and possess advantages such as increased instrument resolution, reduced cos...

ADEOSIIwas launched on Dec., 2002. However, after about 10 months operation, it has lost most of its power due to the solar paddle failure. As a follow on of ADEOSIImission, JAXA is now planning GCOM mission which is composed of a series of satellites. They are now called GCOM-W and GCOM-C satellites. Both satellites are composed of 3 satellites with 5 year lifetime. Hence, 13 years of continuo...

Three atmospheric-chemistry sensors form part of the ENVISAT payload that has been placed into orbit in March 2002. This paper presents reviews the end-toend performance of the GOMOS, MIPAS and SCIAMACHY observation systems and will discuss the product quality control assessment of these instruments. An important part of the quality assessment is the Geophysical Validation. At the ACVT Validati...