Each of a first and a second navigation satellite system (NSS) are adapted to operate according to a first and a second specification, respectively, and each includes a first and a second plurality of satellite vehicles (SV), respectively. Each of the first and the second plurality of SVs are adapted...http://www.google.es/patents/US7893869?utm_source=gb-gplus-sharePatente US7893869 - Global navigation satellite system
