Position location system and method
First Claim
1. A position location system comprising:
- a portable unit comprising a transmitter that transmits a locating signal which is composed of at least two tone components;
a plurality of base stations that receive the locating signal, each base station comprising;
one or more antennas that receive the locating signal, with at least one base station having at least two antennas;
at least one receiver coupled to each of the antennas, the receiver generating values indicative of amplitude and phase of at least two tone components of the locating signal, as received at the corresponding antenna and measured at a defined time; and
a processor that receives the values indicative of amplitude and phase from the plurality of receivers at the base stations, and combines the values indicative of amplitude and phase to determine the position of the portable unit.
2 Assignments
0 Petitions
Accused Products
Abstract
A position location system includes multiple base stations spaced over a region. A portable unit within the region transmits a locating signal which is received by the base stations. The base stations report amplitude, phase and time data related to the locating signal to a control station. The control station includes a processor and memory that combine the data from all of the participating base stations to directly compute an optimal estimate of the location of the portable unit. The control station generates an ambiguity function based upon the probability that the portable unit is located at a particular position. By optimizing the ambiguity function, the error in the computation is minimized to produce an accurate position estimate.
209 Citations
38 Claims
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1. A position location system comprising:
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a portable unit comprising a transmitter that transmits a locating signal which is composed of at least two tone components; a plurality of base stations that receive the locating signal, each base station comprising; one or more antennas that receive the locating signal, with at least one base station having at least two antennas; at least one receiver coupled to each of the antennas, the receiver generating values indicative of amplitude and phase of at least two tone components of the locating signal, as received at the corresponding antenna and measured at a defined time; and a processor that receives the values indicative of amplitude and phase from the plurality of receivers at the base stations, and combines the values indicative of amplitude and phase to determine the position of the portable unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 27, 38)
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13. A position location system comprising:
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a portable unit comprising a transmitter for transmitting a pair of tones in succession; a plurality of base stations for receiving the tones, each base station comprising; a pair of antennas, each of which receives the pair of tones, and a receiver coupled to each antenna that generates a complex-valued representative signal indicative of amplitude and phase of each of the tones as received at the antennas, the receivers being synchronized with one another; and a processor that receives the complex-valued representative signals from the base stations and combines amplitude and phase information for each of the tones to determine the position of the portable unit. - View Dependent Claims (14, 28)
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15. A method of determining position of a portable unit comprising the steps of:
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within the portable unit, transmitting a locating signal composed of at least two tone components; within each of a plurality of base stations, receiving the locating signal at one or more antennas, and within at least one base station, receiving the locating signal with at least two antennas; coupling each antenna to a receiver; within each receiver, generating amplitude and phase values from the locating signal as received by the antenna, the values indicative of amplitude and phase of at least two tone components of the locating signal, as received at the corresponding antenna and measured at defined times; and within a processor, combining the values indicative of amplitude and phase for the tone components from a plurality of the receivers to determine the position of the portable unit. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 29)
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30. A system comprising:
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a plurality of base stations that receive a radio signal from a transmitter and generate in-phase and quadrature complex values indicative of the amplitude and phase of at least two tone components of the radio signal as received at at least one antenna, wherein the complex values are measured within each receiver at a defined time, at least one base station having two or more antennas; and a processor that receives the in-phase and quadrature complex values from the base stations to determine the position of the transmitter. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37)
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Specification