KEEPING ACCURATE TIME FOR A HYBRID GPS RECEIVER AND MOBILE PHONE WHEN POWERED OFF

摘要

A method for keeping accurate time for a hybrid GPS(Global Positioning System) receiver and a portable phone when powered off is provided to get accurate system time from a GPS and a portable phone infrastructure for stabilizing local oscillators and to find carriers in spectrums without search time by having accurate local oscillators. An assembly body of a hybrid GPS receiver and a portable phone comprises a GPS RF(108), a GPS-DSP processing stage(110), a mobile phone transceiver(132), a DSP processing state(134), a master clock(114), an SCXO(Software Control Crystal Oscillator) model(118), a time base(122), a GPS time regenerator(124), and an RTC(Real Time Clock). The GPS RF(108) and a GPS-DSP processing stage(110) calculate position solutions and accurate GPS time. The mobile phone transceiver(132) and the DSP processing state(134) are for cellular communication. The master clock(114) offers a local oscillator frequency reference to the GPS RF(108), the GPS-DSP processing stage(110), the mobile phone transceiver(132), and the DSP processing state(134) independently. The SCXO model(118) controls the master clock(114). The time base(122) supplies accurate clocks to the SCXO model(118) such that errors and deviations of the master clock(114) are compensated for, and receives calculated GPS time via an input module.