Time and Frequency Requirements for an Enhancement of GPS with GEO Satellites

An enhancement of GPS with GEO satellites is proposed. It can enhance the availability of GPS by additional satellites paths and the measurement precision by additional bandwidth. The additional GEO paths signals are precisely synchronized with GPS. The basic requirement for the proposed system is to provide additional positioning links through geo-stationary earth orbit satellites (GES) with distance precision better than 1 meter without causing any serious degradation to the communication services provided by those GES systems. Those requirements necessitate very narrow band delay lock loop (DLL) receivers both at the earth station (ES) and mobile terminal (MT). In order to shorten the acquisition time of those DLL receivers, PN correlators become essential. Correlation time T = 100 mus has been achieved in the convolver array.