Data reader and positioning system
View Patent ↗A data reader can read data regardless of the position of a radio IC tag. The data reader reads data at a separate position from a radio IC tag provided with a storage unit storing data and a communicating antenna for transmitting the data stored in the storage unit, and includes a reader/writer for generating a modulated signal by modulating a carrier wave and a plurality of antenna units for transmitting radio waves for a read for communicating data with a storage medium by radiating the modulated signal into the air. The reader/writer includes a phase adjustment circuit for changing the phase of a carrier wave.
1. A positioning system, comprising:
a plurality of antenna units mounted in different places to read data from storage mediums each having a storage unit for storing data and a communicating antenna for transmission of the data stored in the storage unit, by using radio waves having different polarization directions;
a control unit connected to each antenna unit, for controlling each antenna unit to sequentially change radiation characteristics of each antenna unit;
an antenna switch unit for selectively driving the antenna units in accordance with a control instruction from the control unit to transmit the radio wave having desired polarization directions according to each antenna unit by switching the antenna units; and
a positioning unit for calculating the position of each storage medium on the basis of strengths of signals, the strengths of the signals being obtained as a result of read operations of the data stored in the storage mediums, by using radio waves having different polarization directions, while having each antenna unit sequentially change its radiation characteristics.
2. The positioning system according to claim 1 , wherein the control unit sequentially changes the radiation characteristics of each antenna unit such that no dead spot occurs at a position in which each storage medium is located at one or more time points among a plurality of time points.
3. The positioning system according to claim 1 , wherein the control unit performs the read operations at a plurality of time points, respectively, and determines whether each of the read operations is successful, and
wherein each of the read operations is performed by changing the radiation characteristics.
4. A positioning system, comprising:
a plurality of antenna units mounted in different places to read data from storage mediums each having a storage unit for storing data, and a communicating antenna for transmission of the data stored in the storage unit, by using radio waves having different center frequencies;
a control unit connected to each antenna unit, for controlling each antenna unit to sequentially change radiation characteristics of each antenna unit;
an antenna switch unit for selectively driving the antenna units in accordance with a control instruction from the control unit to transmit the radio wave having desired polarization directions according to each antenna unit by switching the antenna units; and
a positioning unit for calculating the position of each storage medium on the basis of strengths of signals, the strengths of the signals being obtained as a result of read operations of the data of the storage mediums, by using radio waves having different central frequencies, while having each antenna unit sequentially change its radiation characteristics.
5. The positioning system according to claim 4 , wherein the control unit sequentially changes the radiation characteristics of each antenna unit such that no dead spot occurs at a position in which each storage medium is located at one or more time points among a plurality of time points.
6. The positioning system according to claim 4 , wherein the control unit performs the read operations at a plurality of time points, respectively, and determines whether each of the read operations is successful, and
wherein each of the read operations is performed by changing the radiation characteristics.
7. A positioning system, comprising:
a plurality of antenna units mounted in different places to read data from storage mediums each having a storage unit for storing data and a communicating antenna for transmission of the data stored in the storage unit, by using radio waves having different polarization directions and center frequencies;
a control unit connected to each antenna unit, for controlling each antenna unit to sequentially change radiation characteristics of each antenna unit;
an antenna switch unit for selectively driving the antenna units in accordance with a control instruction from the control unit to transmit the radio wave having desired polarization directions according to each antenna unit by switching the antenna units; and
a positioning unit for calculating the position of each storage medium on the basis of strengths of signals, the strengths of the signals being obtained as a result of read operations of the data stored in the storage mediums by using radio waves having different polarization directions and different central frequencies, while having each antenna unit sequentially change its radiation characteristics.
8. The positioning system according to claim 7 , wherein the control unit sequentially changes the radiation characteristics of each antenna unit such that no dead spot occurs at a position in which each storage medium is located at one or more time points among a plurality of time points.
9. The positioning system according to claim 7 , wherein the control unit performs the read operations at a plurality of time points, respectively, and determines whether each of the read operations is successful, and
wherein each of the read operations is performed by changing the radiation characteristics.
10. A positioning system, comprising:
a plurality of antenna units mounted in different places to read data from storage mediums each having a storage unit for storing data and a communicating antenna for transmission of the data stored in the storage unit;
a control unit connected to each antenna unit, for controlling each antenna unit to sequentially change radiation characteristics of each antenna unit;
an antenna switch unit for selectively driving the antenna units in accordance with a control instruction from the control unit to transmit the radio wave having desired polarization directions according to each antenna unit by switching the antenna units; and
a positioning unit for calculating the position of each storage medium by using the number of succeeded read operations which is obtained by having each antenna unit read the storage mediums, while having each antenna unit sequentially change its radiation characteristics.
11. The positioning system according to claim 10 , wherein:
the positioning unit records an intensity of signals received from each storage medium when a read operation is successfully performed on each storage medium, and calculates the position of each storage medium by using the intensity of the signal together with the number of succeeded read operations.
12. The positioning system according to claim 10 , wherein the control unit sequentially changes the radiation characteristics of each antenna unit such that no dead spot occurs at a position in which each of the storage mediums is located at one or more time points among a plurality of time points.
13. The positioning system according to claim 10 , wherein the control unit performs the read operations at a plurality of time points, respectively, and determines whether each of the read operations is successful, and
wherein each of the read operations is performed by changing the radiation characteristics.