Electronic locating system
First Claim
1. A method for electronically locating and tracking persons, animals or objects in a predetermined work area utilizing a number of base stations associated with said work area, provided with stationary transmitting and receiving devices and a number of transponders added to the persons, animals or objects to be located, provided with transmitting and receiving means, wherein in operation each base station generates in the work area a reference field which can be received by the transponders, and wherein each transponder is provided with means to measure the field strength of reference fields generated by the base stations at the location of the transponder and to transmit a signal representing the measured field strength together with an identification code for the respective transponder as a position signal to receiving means provided in the base stations, wherein with the base stations by means of substantially horizontal oriented and substantially planar loop shaped coils low-frequency magnetic fields are transmitted with a unique single unmodulated frequency for each base station;
- wherein the receiving means of the transponders are configured to receive the X, Y, and Z components of each of the field frequencies; and
wherein the transmitting means of the transponders comprise an ultra-high frequency (UHF) transmitter;
wherein position signal transmitted by a transponder represents field strengths of a number of magnetic fields at a location of the transponder and the position of the transponder is calculated on the basis of these signals in a base station or in a central computer connected with the base stations; and
wherein the work area extends within the near field of the applied frequencies of the low-frequency magnetic fields.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and apparatus for electronically locating and tracking persons, animals, or objects in a predetermined work area utilizing a number of base stations associated with the work area, provided with stationary transmitting-/receiving devices and a number of transponders added to the persons, animals, or objects to be located, provided with transmitting and receiving means, wherein the base stations generate interrogation fields which can be received by the transponders, wherein with the base stations low-frequency magnetic fields with a unique frequency for each base station are generated in the predetermined work area, and wherein transponders are used, which are provided with means to measure the field strength associated with each separate received frequency at the location of the transponder and then to transmit this as a position signal via high-frequency transmitting means of the transponder to high-frequency receiving means provided in the base stations.
7 Citations
24 Claims
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1. A method for electronically locating and tracking persons, animals or objects in a predetermined work area utilizing a number of base stations associated with said work area, provided with stationary transmitting and receiving devices and a number of transponders added to the persons, animals or objects to be located, provided with transmitting and receiving means, wherein in operation each base station generates in the work area a reference field which can be received by the transponders, and wherein each transponder is provided with means to measure the field strength of reference fields generated by the base stations at the location of the transponder and to transmit a signal representing the measured field strength together with an identification code for the respective transponder as a position signal to receiving means provided in the base stations, wherein with the base stations by means of substantially horizontal oriented and substantially planar loop shaped coils low-frequency magnetic fields are transmitted with a unique single unmodulated frequency for each base station;
- wherein the receiving means of the transponders are configured to receive the X, Y, and Z components of each of the field frequencies; and
wherein the transmitting means of the transponders comprise an ultra-high frequency (UHF) transmitter;
wherein position signal transmitted by a transponder represents field strengths of a number of magnetic fields at a location of the transponder and the position of the transponder is calculated on the basis of these signals in a base station or in a central computer connected with the base stations; and
wherein the work area extends within the near field of the applied frequencies of the low-frequency magnetic fields. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 23, 24)
- wherein the receiving means of the transponders are configured to receive the X, Y, and Z components of each of the field frequencies; and
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11. An apparatus for electronically locating and tracking persons, animals, or objects in a predetermined work area, comprising a number of base stations associated with said work area, provided with stationary transmitting/receiving devices, and a number of transponders added to the persons, animals or objects to be located, provided with transmitting and receiving means, wherein each base station in operation generates a magnetic reference field which can be received by the transponders, wherein each transponder is provided with means to measure for each frequency received by a transponder the field strength of reference fields generated by the base stations at the location of the transponder and to transmit a signal representing the measured field strength together with an identification code for the transponder as a position signal to receiving means provided in the base stations, wherein the base stations are provided with substantially horizontal placed and substantially planar loop shaped transmitting coils and are configured to generate in the work area low-frequency magnetic fields with a unique single unmodulated frequency for each base station, and wherein the receiving means of the transponders are configured to receive the X, Y, and Z components of each of the low-frequency magnetic fields;
- wherein position signal transmitted by a transponder represents field strengths of a number of magnetic fields at a location of the transponder and the position of the transponder is calculated on the basis of these signals in a base station or in a central computer connected with the base stations; and
wherein the work area extends within the near field of the applied frequencies of the low-frequency magnetic fields. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
- wherein position signal transmitted by a transponder represents field strengths of a number of magnetic fields at a location of the transponder and the position of the transponder is calculated on the basis of these signals in a base station or in a central computer connected with the base stations; and
Specification