Pseudo gps signal transmitting system in a base station

Abstract

The object of this invention is to prevent GPS time monitor errors from effecting the distance-measuring accuracy. To achieve the object, a monitor GPS receiver receives GPS signals from each GPS satellite via a receiving antenna, senses satellite data, and obtains observation data on the basis of user clock pulses synchronized with a reference clock from a reference oscillator. A data processing unit computes a pseudo range error value from the satellite data and observation data obtained at the monitor GPS receiver on the basis of the user clock pulses, and formats these data items to generate transmission data. A transmitter combines PN codes with the transmission data on the basis of the user clock pulses to generate a pseudo GPS signal, modulates a carrier signal synchronized with the reference clock, and power-amplifies the modulated output. A transmitting antenna is directed toward a specific stationary satellite and transmits a pseudo GPS signal to a user GPS receiver via the stationary satellite.