GPSおよび超小型加速度計搭載小型衛星計画

We propose a mission plan by means of a micro-satellite on a Low Earth Orbit (LEO) (300-1,000 km) with an advanced GPS (Global Positioning System) receiving system and a micro accelerometer on board. This LEO satellite can provide the following Earth observations: (1) time variations of low degrees Earth's gravity field coefficients; (2) fluctuations in atmospheric density in the thermosphere estimated from the atmospheric drags; (3) vertical structures of temperature, water vapor and electron density with GPS occultation technique; (4) the sea surface height and surface winds by receiving GPS reflection. The cost of this kind of small satellite is mush smaller than the ordinary earth observation satellites. Thus a large number of this kind of LEO satellites enables the low cost Earth's environments monitoring with high temporal and spatial resolutions in future.