| 摘要 |
A GPS receiver acquires carrier frequency and Gold code phase using short segments of a received GPS signal. In one embodiment, a 1-ms segment (604a) of the GPS signal (602) is transformed to the frequency domain (606/608). This is multiplied (610a) by a frequency representation of the Gold code (609). The resulting product is converted to the time domain (614), and a peak is detected (620). The location of the peak corresponds to the code phase. If n o peak is located, the carrier frequency is changed. Full- and half-bin steps in carrier frequency are considered. Processing gain is achieved by using longe r segments of the input signal, for example 4 or 16 ms and integrating 1-ms segments. Considerations are provided for compensating for the effects of a transition, should it occur in the short segment of the GPS signal being processed. Integrations can be performed using non-coherent and coherent techniques.
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