Location measurement process for radio-frequency badges employing path constraints
First Claim
1. A computer-implemented process for measuring the location of people and objects carrying radio frequency (RF) transmitters (TXs) that transmit messages to a plurality of RE receivers (RXs) located in a space each of which is in communication with a computer of a computer network, wherein each RX forwards data received from the TXs to the network via its associated computer, along with a value indicating the signal strength of the received TX transmission, the process comprising using a centralized computer of the network to perform the following process actions:
- capturing data provided from the RXs which comprises the signal strength of each TX transmission measured by each RX associated with a TX carried by a person or object of interest within the space;
generating a locating signal strength vector representing the signal strength measured by each RX in response to the same TX transmission associated with the TX carried by the person or object of interest;
for each locating signal strength vector generated, comparing the locating vector to previously generated calibration signal strength vectors to determine what calibration vector is most likely to correspond to the locating vector based on any previous computed locations for the person or object being located and a prescribed set of allowable transitions between locations assigned to the calibration vectors, wherein each calibration signal strength vector represents what the signal strengths measured by each RX in response to a TX transmission would be if a TX is placed at said assigned locations in the space, and deeming the person or object being located to be at the location assigned to that calibration vector.
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Accused Products
Abstract
A process for measuring the location of people and objects carrying radio frequency (RF) transmitters (TXs) that transmit messages to a plurality of RF receivers (RXs) located in a space. Each RX is in communication with a computer of a computer network and forwards data received from the TXs to the network via its associated computer, along with a value indicating the signal strength of the received TX transmission. The signal strengths attributable to the same transmission are used to form a locating signal strength vector which is then compared to exemplary vectors generated from signal strength readings gathered in a calibration procedure from a set of representative locations in the space. In comparing the locating vector to the exemplary vectors, constraints are enforced on movements between locations (e.g., cannot pass through walls) and to probabilistically enforce expectations on transitions between locations.
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Citations
23 Claims
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1. A computer-implemented process for measuring the location of people and objects carrying radio frequency (RF) transmitters (TXs) that transmit messages to a plurality of RE receivers (RXs) located in a space each of which is in communication with a computer of a computer network, wherein each RX forwards data received from the TXs to the network via its associated computer, along with a value indicating the signal strength of the received TX transmission, the process comprising using a centralized computer of the network to perform the following process actions:
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capturing data provided from the RXs which comprises the signal strength of each TX transmission measured by each RX associated with a TX carried by a person or object of interest within the space;
generating a locating signal strength vector representing the signal strength measured by each RX in response to the same TX transmission associated with the TX carried by the person or object of interest;
for each locating signal strength vector generated, comparing the locating vector to previously generated calibration signal strength vectors to determine what calibration vector is most likely to correspond to the locating vector based on any previous computed locations for the person or object being located and a prescribed set of allowable transitions between locations assigned to the calibration vectors, wherein each calibration signal strength vector represents what the signal strengths measured by each RX in response to a TX transmission would be if a TX is placed at said assigned locations in the space, and deeming the person or object being located to be at the location assigned to that calibration vector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A location measurement system for measuring the location of persons and objects within a space, comprising:
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at least one radio frequency (RF) transmitters (TX), each of which is carried by the person, or attached to the object, whose location is to be measured and each of which transmits TX messages;
a plurality of RF receivers (RXs), each of which receives TX messages transmitted by TXs within signal range of the RX, said TX messages comprising a transmitter identifier which uniquely identifies the particular TX transmitting the TX message, and wherein each RX measures the strength of the signal carrying a TX message received from a TX;
at least one computing device, each of which is in communication with one or more RXs and which receive data messages from the RXs which are generated upon receipt of a TX message from a TX, wherein the data message comprises the transmitter identifier, a signal strength indicator associated with the TX message and a receiver identifier that uniquely identifies the particular RX sending the data message;
a centralized computing device which is in communication with each of the computing devices associated with a RX via said network and which receives badge hit messages each of which represents a version of the forwarded RX data messages with an identifier identifying the computing device forwarding the message appended thereto; and
a computer program comprising program modules executable by the centralized computing device, wherein the centralized computing device is directed by the program modules of the computer program to, generate a locating signal strength vector representing the signal strength measured by each RX in response to the same TX transmission associated with the TX carried by the person or object of interest within the space using the badge hit messages received via said network, and for each locating signal strength vector generated, compare the locating vector to previously generated calibration signal strength vectors to determine what calibration vector is most likely to correspond to the locating vector based on any previous computed locations for the person or object being located and a prescribed set of allowable transitions between locations assigned to the calibration vectors, and deeming the person or object of interest to be at a location assigned to that calibration vector, wherein each calibration signal strength vectors represents what the signal strengths measured by each RX in response to a TX transmission would be if a TX is placed at said assigned locations in the space. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A computer-readable medium having computer-executable instructions for measuring the location of people and objects carrying radio frequency (RF) transmitters (TXs) that transmit messages to a plurality of RF receivers (RXs) located in a space each of which is in communication with a computer of a computer network, wherein each RX forwards data received from the TXs to the network via its associated computer, along with a value indicating the signal strength of the received TX transmission, said computer-executable instructions comprising:
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in a calibration phase, storing a representation of a space in which the location of a person or object carrying a TX is to be measured, wherein the representation comprises the coordinates and name of representative locations in the space where the person or object might be located at any point in time, capturing calibration data provided from the RXs which comprises the signal strength of each TX transmission measured by each RX when a TX is respectively placed at each of the representative locations in the space, and generating a calibration signal strength vector representing the signal strength measured by each RX in response to the same TX transmission and assigning the calibration vector to the representative location where the TX was placed when the transmission was made; and
in a locating phase, capturing data provided from the RXs which comprises the signal strength of each TX transmission measured by each RX associated with a TX carried by a person or object of interest within the space, generating a locating signal strength vector representing the signal strength measured by each RX in response to the same TX transmission associated with the TX carried by the person or object of interest, and for each locating signal strength vector generated, comparing the locating vector to the previously generated calibration signal strength vectors to determine what calibration vector is most likely to correspond to the locating vector based on any previous computed locations for the person or object being located and a prescribed set of allowable transitions between locations assigned to the calibration vectors, and deeming the person or object of interest to be at the location associated with that calibration vector.
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22. A computer-implemented process for measuring the location of people and objects carrying radio frequency (RF) receivers (RXs) that receive messages transmitted by a plurality of RF transmitters (TXs) located in a space, wherein each RX is in communication with a centralized computer of a computer network and forwards data received from the TX transmissions via the network to said centralized computer, along with a value indicating the signal strength of each received TX transmission, the process comprising using a centralized computer of the network to perform the following process actions:
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capturing data provided from the RXs which comprises the signal strength of each TX transmission measured by each RX associated with a person or object of interest within the space;
generating a locating signal strength vector representing the signal strengths measured by a RX carried by the person or object of interest in response to TX transmissions received within a prescribed period of time;
for each locating signal strength vector generated, comparing the locating vector to previously generated calibration signal strength vectors to determine what calibration vector is most likely to correspond to the locating vector based on any previous computed locations for the person or object of interest and a prescribed set of allowable transitions between locations assigned to the calibration vectors, wherein each calibration signal strength vectors represents what the signal strengths measured by the RX carried by the person or object of interest in response to TX transmissions received within a prescribed period of time would be if the RX is placed at said assigned locations in the space, and deeming the person or object being located to be at the location assigned to that calibration vector.
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23. A computer-implemented process for measuring the location of people and objects carrying radio frequency (RF) receivers (RXs) that receive messages transmitted by a plurality of RF transmitters (TXs) located in a space, wherein each RX measures a value indicating the signal strength of each received TX transmission, the process comprising the following process actions:
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generating a locating signal strength vector representing the signal strengths measured by a RX carried by the person or object of interest in response to TX transmissions received within a prescribed period of time;
for each locating signal strength vector generated, comparing the locating vector to previously generated calibration signal strength vectors to determine what calibration vector is most likely to correspond to the locating vector based on any previous computed locations for the person or object of interest and a prescribed set of allowable transitions between locations assigned to the calibration vectors and deeming the person or object being located to be at a location assigned to that calibration vector, wherein each calibration signal strength vectors represents what the signal strengths measured by the RX carried by the person or object of interest in response to TX transmissions received within a prescribed period of time would be if the RX is placed at said assigned locations in the space.
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Specification