Exploring constellation coverage of China

The specific target area we study is bounded by north latitudes 4.25° and 53.5167° and east longitudes 73.6667° and 135.0833°; this target area includes China completely. Before starting in-depth study, we first test our ideas with the simple evaluation-version STK-Satellite Tool Kit. We use circular synchronous orbits with repeatable ground traces to constitute our Earth-observation constellation. In this kind of orbits, the most important factor is orbital altitude, which we use well-known analytic method to determine as 786 km. Our constellation has only two orbital planes with one satellite in each plane. The simulation and computation are performed by evaluation-version STK-Satellite Tool Kit. The results show preliminarily that the accumulated coverage, the average coverage, and the maximum coverage respectively are 90.54%, 0.27% and 8.36%. These results are quite satisfactory and are a good starting point for our in-depth study.