| 摘要 |
A method and apparatus are disclosed for fixing the location of a receiver using transmitted signals that include a unique periodically repeating sequence. The apparatus and method are useful in communication systems, especially unsynchronized systems, such as A-GPS utilized on GSM and UMTS cellular telephone systems. A received signal is stored by the receiver for at least two repetitions of the periodically repeating sequence. FFT operations are performed, and the resulting data frequency samples are pruned responsiv e to a hypothesized residual frequency. This reduces the number of subsequent calculations required and the processing time. A correlation series is determined from the pruned samples and reference frequency samples corresponding to a hypothesized transmitter. If a match is found, a code pha se offset is determined; if not, the process is repeated with another hypothesized residual frequency. Multiple correlation series similarly obtained may also be incoherently combined prior to this examination.</SDOAB >
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