| 摘要 |
FIELD: radar-location. ^ SUBSTANCE: invention relates to methods and a device for establishing location of a receiver using GPS signals. The invention employs signals of GPS transmitters, which comprise a unique periodically recurring pseudonoise (PN) sequence. The invention is especially useful in non-synchronised systems, for example A-GPS, used in GSM and UMTS systems for mobile telephones. A received signal is stored in a receiver for at least two repetition periods of the PN sequence. A fast Fourier transformation operation is done (FFT), and frequency samples of data are obtained, which are curtailed in response to a hypothetical residual frequency. This cuts the number of the next required calculations and processing time. Correlation series are determined from the curtailed samples and reference frequency samples of the corresponding hypothetical transmission. If conformity is detected, the displacement of code shift is determined. Otherwise the process is repeated with another hypothetical residual frequency. Several similar obtained correlation series can be joined incoherently. ^ EFFECT: device and method of detecting GPS signals. ^ 25 cl, 13 dwg |
