US 2003/0206115 A1Published application

Location measurement process for radio-frequency badges

AssigneeMicrosoft Corporation

InventorsJohn Krumm, Gregory Smith, Barrett L. Brumitt, Stephen C. Harris

Life of this patent

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Abstract

A process for determining the location of entities carrying transmitters (TXs) that transmit TX ID messages to at least one receiver (RX) connected to a computer, in a network of computers. Each RX sends data messages to its associated computer which includes an identifier identifying the TX transmitting the TX ID message, the signal strength of the received TX ID message, and a RX identifier. Each RX computer generates badge hit messages from each data message, and provides them to a centralized computer of the network. The centralized computer generates a badge hit table having a separate entry for each badge hit message, which has fields including the information received in the badge hit message and a hit time indicating the time the entry was added to the table. The badge hit table data is used to determining the location of the TXs, and so the entities.

Claims38

Dependent claims

A computer-implemented process for determining the location of people and objects carrying radio frequency (RF) transmitters (TXs) that transmit TX ID messages to at least one RF receiver (RX) which is in communication with a computer in a computer network, wherein each RX forwards data received from the TXs to the network, along with a value indicating the signal strength of the received TX message, the process comprising using a computer to perform the following process actions:

each computer associated with a RX generating badge hit messages upon receipt of a data message from the RX and providing the badge hit messages to a centralized computer of the network, wherein each badge hit message includes information received in the data message comprising a transmitter identifier, the signal strength indicator associated with the TX ID message and a receiver identifier that uniquely identifies the particular RX sending the data message;
generating a badge hit table in a badge hit database residing on the centralized computer, wherein the badge hit table has a separate entry derived from each badge hit message received whose fields comprise the information received in the badge hit message and a hit time assigned to the entry indicating the time the entry was added to the badge hit table;
determining the location of each TX transmitting a TX ID message using the badge hit data;
and
updating an entity location table of a geometric model database with the location of entities included therein, wherein the entity location table comprises a list of entities and the TX identifier of a TX that is associated with each entity, as well as the location of the entity if known, and wherein said entity is a person, object or a collection of persons and objects and the location of the entity is the location determined for the TX associated with the entity.

2 more elements

A location tracking system for determining the location of persons and objects using transmitters that transmit TX ID messages to at least one receiver connected to a computing device in a network of computing devices, comprising:

a plurality of radio frequency (RF) transmitters (TXs), each of which is carried by the person, or attached to the object, whose location is to be determined;
at least one RF receiver (RX), each of which receives TX ID messages transmitted by TXs within signal range of the RX, said TX ID messages comprising a transmitter identifier which uniquely identifies the particular TX transmitting the TX ID message, and wherein each RX measures the strength of the signal carrying a TX ID message received from a TX;
at least one computing device, each of which is in communication with a different RX and which receives data messages from the RX which are generated upon receipt of a TX ID message from a TX, wherein the data message comprises the transmitter identifier, a signal strength indicator associated with the TX ID 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 computing device is directed by the program modules of the computer program to determine the location of each TX using the data forwarded to it from each computing device associated with a RX.

3 more elements

A computer-readable medium having computer-executable instructions for determining the location of entities carrying RF transmitters that transmit TX ID messages to at least one receiver connected to a computing device in a network of computing devices from a data table having entries for each TX ID message received comprising fields for a PIN identifying an entity associated with the transmitter responsible for the TX ID message, the signal strength indicator indication the strength of the RF signal carrying the TX ID message, a receiver identifier that identifies the receiver receiving the TX ID message, and a hit time indicating the time the entry was added to the data table, said computer-executable instructions comprising:

screening the entries of the data table to ensure that only entries having a signal strength value equaling or exceeding a prescribed level, and that only one entry per transmission, are used to determine the location of a transmitter whose transmission resulted in the entry;
and
determining the location of the transmitter associated with each of the screened entries having a signal strength value equaling or exceeding the prescribed level and representing the only entry attributable to a transmission that is used to determine an entities location, based on a known location of the receiver identified in the entry;
and
equating the transmitter's location to the entity whose PIN is listed in the entry under consideration.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/137,238Filed 1 May 2002
Published: 6 Nov 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G06K 7/10079
Resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers.: the collision being…
G06K 7/0008
Methods or arrangements for sensing record carriers, e.g. for reading patterns: general problems related to the reading of electronic memory…
H04L 2012/2841
Characterised by the type of medium used: wireless
H04W 64/00
Locating users or terminals or network equipment for network management purposes