| 摘要 |
A test scanner located where it does not directly receive GPS signals relies on a second device, a reference transmitter with a GPS receiver, to provide time information. The reference transmitter has an internal GPS synchronized clock and a pilot transmission pattern that serves as a marker. The reference transmitter is positioned within close proximity to the test scanner. The reference transmitter periodically receives GPS signals and sets its reference internal clock accordingly. This reference transmitter transmits its highly recognizable signal with time synchronization information. The test scanner, able to distinguish between the reference pilot and base station pilot signals, receives the marked signal and uses the timing information to set the test scanner's internal clock. The test scanner can then perform a pilot scan of one or more CDMA base station pilot channels. Measurement and evaluation of signal propagation coverage and adequacy can thus be made from an interior or otherwise GPS obstructed location.
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