Optimized polar orbit constellations for redundant earth coverage

An analytical solution has been obtained to identify the minimum number of satellite polar orbit families which provide at least two fold redundant coverage at or above a latitude of 50 degrees. It is shown that the required number of satellites required varies in relation to the altitude of the coverage and the desired redundancy of coverage n. The orbit families providing two-, four-, and sixfold redundant coverage at a latitude of zero degrees are given in a table.