GPS receiver utilizing a communication link
First Claim
1. In a method for determining the position of a remote unit, a process comprising:
- receiving, at said remote unit from a transmission cell in a cellular communication system, a Doppler information of a satellite in view of said remote unit; and
computing, in said remote unit, a position information for said satellite by using said Doppler information without receiving and without using satellite ephemeris information.
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Accused Products
Abstract
A GPS receiver in one embodiment includes an antenna which receives GPS signals at an RF frequency from in view satellites; a downconverter coupled to the antenna for reducing the RF frequency of the received GPS signals to an intermediate frequency (IF); a digitizer coupled to the downconverter and sampling the IF GPS signals at a predetermined rate to produce sampled IF GPS signals; a memory coupled to the digitizer storing the sampled IF GPS signals (a snapshot of GPS signals); and a digital signal processor (DSP) coupled to the memory and operating under stored instructions thereby performing Fast Fourier Transform (FFT) operations on the sampled IF GPS signals to provide pseudorange information. These operations typically also include preprocessing and post processing of the GPS signals. After a snapshot of data is taken, the receiver front end is powered down. The GPS receiver in one embodiment also includes other power management features and includes, in another embodiment the capability to correct for errors in its local oscillator which is used to sample the GPS signals. The calculation speed of pseudoranges, and sensitivity of operation, is enhanced by the transmission of the Doppler frequency shifts of in view satellites to the receiver from an external source, such as a basestation in one embodiment of the invention.
732 Citations
36 Claims
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1. In a method for determining the position of a remote unit, a process comprising:
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receiving, at said remote unit from a transmission cell in a cellular communication system, a Doppler information of a satellite in view of said remote unit; and computing, in said remote unit, a position information for said satellite by using said Doppler information without receiving and without using satellite ephemeris information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A mobile unit which uses data representative of GPS signals to provide the position of said mobile unit, said mobile unit comprising;
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a receiver in said mobile unit, said receiver operable for coupling through a cellular communications link in a transmission cell to receive a Doppler information of a satellite in view of said mobile unit; a processing unit in said mobile unit, said processing unit coupled to said receiver to receive said Doppler information and compute a position information for said satellite by using said Doppler information without receiving and without using satellite ephemeris information. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of using a basestation for providing a communications link to a mobile GPS unit, said method comprising:
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determining a Doppler information of a satellite in view of said mobile GPS unit, wherein said Doppler information is used by said mobile GPS unit to determine a position information for said satellite; transmitting from a transmission cell in a cellular communication system said Doppler information of said satellite in view to said mobile GPS unit wherein said mobile GPS unit determines said position information without receiving and without using satellite ephemeris information. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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26. A basestation for providing a cellular communication link to a mobile GPS unit, said basestation comprising:
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a source of a Doppler information of a satellite in view of said mobile GPS unit; a transmitter coupled to said source of said Doppler information, said transmitter for transmitting through said cellular communications link in a transmission cell said Doppler information to said mobile GPS unit wherein said mobile GPS unit determines a position information without receiving and without using satellite ephemeris information. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A method for determining the position of a remote unit, comprising the steps of:
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transmitting through a transmission cell in a cellular communication system GPS satellite information, including Doppler information, to a remote unit from a basestation via a cellular data link; receiving at said remote unit said satellite information and GPS signals from in view satellites; computing, in the remote unit, pseudoranges to said in view satellites said pseudoranges computed using said Doppler information wherein said remote unit determines said pseudoranges without receiving and without using satellite ephemeris information; transmitting said pseudoranges to said basestation from said remote unit via said cellular data link; and computing, at said basestation, the position of said remote unit, using said pseudoranges.
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Specification