Providing global positioning system (GPS) timing signals to remote cellular base stations
First Claim
Patent Images
1. A method comprising:
- generating an oscillating signal and a timing pulse signal having a fixed frequency from received global positioning system signals at a first location;
modulating the oscillating signal with the timing pulse signal to produce a modulated signal, wherein modulating the oscillating signal with the timing pulse signal comprises using the oscillating signal to generate a pseudorandom noise code of symbols that repeats over time at a frequency of no greater than the fixed frequency of the timing pulse signal, wherein for each instance of the pseudorandom noise code of symbols, the occurrence of a timing pulse in the timing pulse signal is aligned with a predetermined position of one of the symbols in the pseudorandom noise code of symbols; and
transmitting the modulated signal to a device located at a second location through a communications channel, the device being configured to process the modulated signal to attempt to synchronize the device to global positioning system time.
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Abstract
In a cellular network, a GPS receiver includes circuitry that modulates a global positioning system (GPS) timing pulse signal with a carrier signal and transmits the modulated signal to one or more remote base stations. When the modulated timing pulse signal is received at a remote base station it is demodulated and a timing pulse signal corresponding to the GPS timing pulse signal is recovered. The remote base station may be configured to transmit a reply signal back to the GPS receiver, which can then be used to estimate a propagation delay between the GPS receiver and the remote base station.
167 Citations
47 Claims
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1. A method comprising:
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generating an oscillating signal and a timing pulse signal having a fixed frequency from received global positioning system signals at a first location; modulating the oscillating signal with the timing pulse signal to produce a modulated signal, wherein modulating the oscillating signal with the timing pulse signal comprises using the oscillating signal to generate a pseudorandom noise code of symbols that repeats over time at a frequency of no greater than the fixed frequency of the timing pulse signal, wherein for each instance of the pseudorandom noise code of symbols, the occurrence of a timing pulse in the timing pulse signal is aligned with a predetermined position of one of the symbols in the pseudorandom noise code of symbols; and transmitting the modulated signal to a device located at a second location through a communications channel, the device being configured to process the modulated signal to attempt to synchronize the device to global positioning system time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. Apparatus comprising:
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a global positioning receiver configured to receive signals from a constellation of global positioning satellites and produce a timing pulse signal having a fixed frequency; a pseudorandom noise code generator configured to generate a pseudorandom noise code of symbols that repeats over time at a frequency of no greater than the fixed frequency of the timing pulse signal, wherein for each instance of the pseudorandom noise code of symbols, the occurrence of a timing pulse in the timing pulse signal is aligned with a predetermined position of one of the symbols in the code; and a transmitter configured to transmit the pseudorandom noise code of symbols to a remote device. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A base station for use in a cellular communication network, the base station comprising:
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an input configured to receive a modulated timing pulse signal derived from a timing pulse signal having a fixed frequency, the modulated timing pulse signal being generated by a remote global positioning system receiver, wherein the modulated timing pulse signal comprises a pseudorandom noise code of symbols having a frequency no greater than that of the fixed frequency of the timing pulse signal; and a demodulation circuit operably connected to the input and configured to demodulate the modulated timing pulse signal to derive a second timing pulse signal corresponding to the timing pulse signal of the remote global positioning system receiver to attempt to synchronize the base station to global positioning system time, wherein the demodulation circuit comprises; a shift register circuit configured to receive the pseudorandom noise code of symbols and produce a pulse when a sequence of symbols in the pseudorandom noise code of symbols matches with a predetermined sequence of symbols; and an oscillator configured to drive the shift register circuit at a reference frequency. - View Dependent Claims (40, 41, 42, 43)
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44. A method for providing timing information to a base station in a cellular network, the method comprising:
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receiving global positioning signals from a constellation of global positioning satellites; generating a first timing pulse signal having a series of timing pulses occurring at a fixed frequency from the global positioning signals; modulating, at a first location, the first timing pulse signal with a carrier signal to produce a modulated signal, wherein modulating the first timing pulse with signal with the carrier signal comprises generating a pseudorandom noise code of symbols that repeats over time at a frequency of no greater than the fixed frequency of the first timing pulse signal, wherein for each instance of the pseudorandom noise code of symbols, the occurrence of a timing pulse of the series of timing pulses in the first timing pulse signal is aligned with a predetermined position of one of the symbols in the pseudorandom noise code of symbols; and transmitting the modulated signal to the base station, the base station being located at a second location, wherein the second location is remote from the first location, and wherein the base station is configured to process the modulated signal to attempt to synchronize the base station to global positioning system time. - View Dependent Claims (45, 46, 47)
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Specification