System and method for determining the position of a wireless CDMA transceiver
First Claim
1. A system for determining a position of a mobile wireless transceiver comprising:
- a base station;
means for calculating a Doppler shift of signals transmitted from first, second and third satellites, respectively, relative to the base station;
means for calculating a first set of pseudo ranges of the first and second satellites, respectively, relative to said base station;
means for sending satellite identification information, Doppler shift information, and said pseudo range information between said base station and said wireless transceiver;
means disposed at said wireless transceiver for receiving said satellite identification information, Doppler shift information, and said pseudo range information from said base station;
means disposed at said mobile wireless transceiver for utilizing said information received from said base station to identify a second set of pseudo ranges between said transceiver and said first and second satellites, respectively, at a time T;
means disposed at said mobile wireless transceiver for sending to said base station said second set of pseudo ranges between said transceiver and said first and second satellites, respectively, along with time information for the time T; and
means disposed at the base station for calculating the position of said wireless transceiver in response to said second set of pseudo ranges and said time information for the time T.
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Accused Products
Abstract
A system and method for determining a position of a mobile wireless transceiver. The inventive system merges GPS position location and wireless communication technologies to achieve a precise position location in dense urban and other environments when line-of-sight to the satellites is somewhat obscured. The inventive method uses signals from only two GPS satellites and the serving terrestrial base station. In a most general sense, the inventive method includes the steps of receiving at a base station a first signal transmitted from a first GPS satellite and a second signal transmitted from a second GPS satellite. The mobile transceiver is adapted to receive these GPS signals as well and transmit a third signal to the base station in response thereto. The base station receives the third signal and uses it to calculate the position of the wireless unit. In a specific implementation, the base station sends aiding information to the wireless unit. The aiding information is used by the wireless unit to quickly acquire the signals transmitted by the first and second satellites and includes satellite identification information, Doppler shift information, and range information between the base station and the satellites. On the acquisition by the wireless unit of the signals transmitted by the first and second satellites, the wireless unit wireless unit calculates the range between the wireless unit and each of the satellites. This range information is transmitted back to the base station along with information as to the time at which the measurement was made. In a CDMA implementation, the time at which the wireless unit transmits the third signal to the base station is known by the base station. The delay in the receipt of the third signal provides an indication to the base station as to the range between the base station and the wireless unit. The base station utilizes information known as to its position, the position of the first and second satellites relative to the wireless unit and the range to the wireless unit from the base station to calculate the position of the wireless unit.
346 Citations
21 Claims
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1. A system for determining a position of a mobile wireless transceiver comprising:
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a base station; means for calculating a Doppler shift of signals transmitted from first, second and third satellites, respectively, relative to the base station; means for calculating a first set of pseudo ranges of the first and second satellites, respectively, relative to said base station; means for sending satellite identification information, Doppler shift information, and said pseudo range information between said base station and said wireless transceiver; means disposed at said wireless transceiver for receiving said satellite identification information, Doppler shift information, and said pseudo range information from said base station; means disposed at said mobile wireless transceiver for utilizing said information received from said base station to identify a second set of pseudo ranges between said transceiver and said first and second satellites, respectively, at a time T; means disposed at said mobile wireless transceiver for sending to said base station said second set of pseudo ranges between said transceiver and said first and second satellites, respectively, along with time information for the time T; and means disposed at the base station for calculating the position of said wireless transceiver in response to said second set of pseudo ranges and said time information for the time T. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for determining a position of a mobile wireless transceiver comprising:
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a base station; means disposed at the base station for identifying first and second Global Positioning System satellites; means for calculating a Doppler shift of signals transmitted from said first and second satellites, respectively, relative to the base station; means for calculating a first set of pseudo ranges of the first and second satellites, respectively, relative to said base station; means for sending satellite identification information, Doppler shift information, and said pseudo-range information from said base station to said wireless transceiver; means disposed at said wireless transceiver for receiving said satellite identification information, Doppler shift information, and said pseudo range information from said base station; means disposed at said mobile wireless transceiver for utilizing said information received from said base station to identify a second set of pseudo ranges between said transceiver and said first and second satellites, respectively, at a time T; means disposed at said mobile wireless transceiver for sending to said base station said second set of pseudo ranges between said transceiver and said first and second satellites, respectively, along with time information for the time T and means disposed at the base station for calculating the position of said wireless transceiver in response to said second set of pseudo ranges and said time information for the time T said means for calculating including; means for determining the distance of said wireless transceiver from said base station and means for utilizing the distance of said wireless transceiver from said base station in the calculation of the position of said wireless transceiver. - View Dependent Claims (10, 11, 12, 13)
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14. A method for determining a position of a mobile wireless transceiver including the steps of:
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calculating Doppler shift of signals transmitted from first and second satellites, respectively, relative to a base station; calculating a first set of pseudo ranges of the first and second satellites, respectively, relative to said base station; sending satellite identification information, Doppler shift information, and said pseudo-range information from said base station to said wireless transceiver; receiving, at said transceiver, said satellite identification information, Doppler shift information, and said pseudo range information from said base station; utilizing said information received from said base station to identify a second set of pseudo ranges between said transceiver and said first and second satellites, respectively, at a time T; sending to said base station said second set of pseudo ranges between said transceiver and said first and second satellites, respectively, along with time information for the time T; and calculating the position of said wireless transceiver in response to said second set of pseudo ranges4,5 and said time information tx. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification