JP2009152660A - Active radio tag, radio receiver, location detector, and location detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active radio tag capable of improving measurement precision of a location without providing a receiving function. <P>SOLUTION: Radio waves R1 and R2 transmitted from the active radio tag 11 are received in order by receivers 12a to 12d, intensities of the radio waves R1 and R2 are measured, and the intensities of the radio waves R1 and R2 measured by the receivers 12a to 12d and ID data of the active radio tag 11 are transmitted to a personal computer 13, which detects the location of the active radio tag 11 based upon the intensity of the radio wave R1 including the ID data when the intensity of the radio wave R1 received by the receivers 12a to 12d and including the ID data does not get saturated, or detects the location of the active radio tag 11 based upon the intensity of the radio wave R2 transmitted right after the radio wave R1 including the ID data when the intensity of the radio wave R1 received by the receivers 12a to 12d and including the ID data gets saturated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an active wireless tag, a wireless reception device, a position detection device, and a position detection system, and is particularly suitable for application to a method for detecting a position based on the intensity of a radio wave transmitted from an active wireless tag.

In hospitals and sales outlets, in order to grasp the current positions of employees and employees, receivers are installed at each point in the building and site, and active wireless tags are held by employees and employees. May detect the current position of employees or employees from the intensity of radio waves transmitted from the.
Further, for example, in Patent Document 1, when a radio station of a mobile station receives a predetermined radio wave, a radio wave of a response signal is emitted and its transmission power is gradually reduced. When the radio wave of the machine is received, the received signal is notified to the control means, and the control means identifies one of the detection radios that has been notified of reception until the latest, and the identified detection signal A method for determining that a mobile station radio exists in the vicinity of the radio is disclosed.
Japanese Patent Laid-Open No. 2006-19840

However, even if the active wireless tag and the receiver are separated from each other to some extent, the intensity of the radio wave transmitted from the active wireless tag is set so that a predetermined sensitivity can be obtained at the receiver. For this reason, in the conventional position detection method, when the active wireless tag approaches the receiver, the intensity of the radio wave received by the receiver increases, so that the intensity of the radio wave received by the receiver is saturated, and the active radio tag There was a problem that the measurement accuracy of the tag position deteriorated.
Further, in the method disclosed in Patent Document 1, when the mobile station receives a predetermined radio wave, both the transmitter and the receiver are connected to the mobile station in order to emit a response signal radio wave and gradually reduce its transmission power. There is a problem that the configuration of the mobile station needs to be installed and the scale of the mobile station increases.
Accordingly, an object of the present invention is to provide an active wireless tag, a wireless reception device, a position detection device, and a position detection system that can improve the position measurement accuracy without providing a receiver.

In order to solve the above-described problem, according to the active wireless tag according to claim 1, first wireless transmission means for wirelessly transmitting ID data for identifying itself when a predetermined period or a predetermined condition is satisfied, and transmission of the ID data Immediately after the second wireless transmission means for transmitting a radio wave having a weaker intensity than the radio wave at the time of transmission of the ID data.
According to another aspect of the wireless receiver of the present invention, the radio wave including the ID data transmitted from the active radio tag and the radio wave having a lower intensity than the radio wave transmitted immediately after the ID data is transmitted. Radio receiving means; radio wave intensity measuring means for measuring the intensity of radio waves received by the radio receiving means; radio wave intensity including ID data measured by the radio wave intensity measuring means; and radio wave intensity immediately thereafter Communication means for transmitting together with the ID data.

  According to the position detecting device of claim 3, the intensity of the radio wave including the ID data transmitted from the active radio tag and the intensity of the radio wave weaker than that at the time of transmission of the ID data transmitted immediately thereafter are obtained. Receiving means for receiving together with the ID data; saturation determining means for determining whether the intensity of radio waves including the ID data transmitted from the active wireless tag is saturated; and ID data transmitted from the active wireless tag When the intensity of the radio wave including is not saturated, first position detecting means for detecting the position of the active radio tag based on the intensity of the radio wave including the ID data, and ID data transmitted from the active radio tag If the intensity of the radio wave including the signal is saturated, the actuator is activated based on the intensity of the radio wave transmitted immediately after the radio wave including the ID data. Characterized in that it comprises a second position detecting means for detecting the position of the probe wireless tag.

  According to the position detection system of claim 4, the active wireless tag that transmits a radio wave that is weaker than the radio wave at the time of transmission of the ID data immediately after transmission of the ID data that identifies itself, and the active wireless tag A radio that receives a radio wave including ID data transmitted from a tag and a weak radio wave transmitted immediately thereafter, and transmits the intensity of the radio wave including the ID data and the radio wave intensity immediately after the radio wave together with the ID data; When the intensity of the radio wave including the ID data received by the wireless device is saturated, the position of the active wireless tag is detected based on the intensity of the radio wave transmitted immediately after the radio wave including the ID data. And a position detection device.

  As described above, according to the present invention, the active wireless tag approaches the receiver by transmitting from the active wireless tag a radio wave weaker than the radio wave at the time of transmitting the ID data immediately after transmitting the ID data. Even in this case, it is possible to receive a radio wave whose intensity is not saturated at the receiver without weakening the intensity of the radio wave when transmitting the ID data. For this reason, it is possible to improve the measurement accuracy of the position of the active wireless tag without providing a receiver in the active wireless tag, and accurately grasp the position of the moving object while suppressing an increase in the size of the active wireless tag. It becomes possible.

Hereinafter, a position detection system to which an active wireless tag according to an embodiment of the present invention is applied will be described with reference to the drawings.
Fig.1 (a) is a block diagram which shows schematic structure of the position detection system which concerns on one Embodiment of this invention.
In FIG. 1A, an active wireless tag 11, receivers 12a to 12d, and a personal computer 13 are provided in the position detection system. Here, the receivers 12a to 12d can be installed in a building such as a hospital or a building, and the receivers 12a to 12d and the personal computer 13 are connected via a communication line such as serial communication. Further, the active wireless tag 11 can be provided to a moving body such as a staff member or an employee who moves in a building such as a hospital or a building.

  Here, the active wireless tag 11 can transmit radio waves having a weaker intensity than the radio waves at the time of transmission of the ID data to the receivers 12a to 12d immediately after transmission of the ID data for identifying itself. The receivers 12a to 12d receive the radio wave including the ID data transmitted from the active wireless tag 11 and the weak radio wave transmitted immediately thereafter, and determine the intensity of the radio wave including the ID data and the radio wave intensity immediately thereafter. It can be transmitted to the personal computer 13 together with the ID data. When the intensity of the radio wave including the ID data received by the receivers 12a to 12d is saturated, the personal computer 13 uses the active wireless tag based on the intensity of the radio wave transmitted immediately after the radio wave including the ID data. 11 positions can be detected.

FIG. 1B is a diagram illustrating a configuration of wireless data transmitted from the active wireless tag.
In FIG. 1B, the wireless data transmitted from the active wireless tag can be composed of a radio wave R1 including ID data and a radio wave R2 transmitted immediately thereafter. Arbitrary data can be placed on the radio wave R2, and empty data may be placed. For example, the transmission time of the radio wave R1 can be set to several tens of msec, and the transmission time of the radio wave R2 can be set to a few msec that is sufficiently shorter than the transmission time of the radio wave R1. Thereby, even when the radio wave R2 is transmitted immediately after the radio wave R1, an increase in power consumption can be suppressed, and battery consumption can be suppressed.

FIG. 1C is a diagram illustrating the relationship between the radio wave intensity of the wireless data transmitted from the active wireless tag and the distance from the active wireless tag.
In FIG. 1C, the intensity of the radio wave R1 including the ID data is set so that the ID data of the active wireless tag 11 can be specified even if the active wireless tag 11 and the receivers 12a to 12d are separated to some extent. . For this reason, when the active wireless tag 11 approaches the receivers 12a to 12d, the strength of radio waves received by the receivers 12a to 12d increases, and the strength of radio waves received by the receivers 12a to 12d is saturated.
On the other hand, the intensity of the radio wave R2 transmitted immediately after the radio wave R1 including the ID data is such that the intensity of the radio wave received by the receivers 12a to 12d even when the active wireless tag 11 approaches the receivers 12a to 12d. For example, it can be set to about 1/10 of the radio wave R1.

  The active wireless tag 11 transmits a radio wave R1 including ID data, and immediately after that, a radio wave R2 having a lower intensity than the radio wave R1 is transmitted. The radio waves R1 and R2 transmitted from the active wireless tag 11 are sequentially received by the receivers 12a to 12d, and the strengths of the radio waves R1 and R2 are measured. The intensity of the radio waves R1 and R2 measured by the receivers 12a to 12d and the ID data of the active wireless tag 11 are sent to the personal computer 13 by serial communication, and the radio wave R1 is saturated by the personal computer 13. It is judged whether or not. When the intensity of the radio wave R1 including the ID data received by the receivers 12a to 12d is not saturated, the personal computer 13 determines the position of the active wireless tag 11 based on the intensity of the radio wave R1 including the ID data. To detect. On the other hand, when the intensity of the radio wave R1 including the ID data received by the receivers 12a to 12d is saturated, the personal computer 13 is based on the intensity of the radio wave R2 transmitted immediately after the radio wave R1 including the ID data. Then, the position of the active wireless tag 11 is detected.

  For example, when the distance between the active wireless tag 11 and the receivers 12a to 12d is H4, H2, H3, and H1, respectively, as shown in FIG. Since the intensity of the included radio wave R1 is saturated, the distance between the active wireless tag 11 and the receivers 12b and 12d is determined based on the intensity of the radio wave R2 transmitted immediately after the radio wave R1 including the ID data. The On the other hand, in the receivers 12a and 12c, the intensity of the radio wave R1 including the ID data is not saturated. Therefore, based on the intensity of the radio wave R1 including the ID data, between the active wireless tag 11 and the receivers 12a and 12c. The distance is determined.

  As a result, when the active wireless tag 11 approaches the receivers 12a to 12d by transmitting from the active wireless tag 11 a radio wave R2 having a lower intensity than the radio wave R1 at the time of transmitting ID data immediately after transmitting the ID data. In this case, the receivers 12a to 12d can receive the radio wave R2 whose intensity is not saturated without weakening the intensity of the radio wave R1 when transmitting the ID data. For this reason, it is possible to improve the measurement accuracy of the position of the active wireless tag 11 without providing a receiver in the active wireless tag 11, and to accurately increase the position of the moving object while suppressing the increase in the scale of the active wireless tag 11. It becomes possible to grasp well.

FIG. 2 is a block diagram showing a schematic configuration of an active wireless tag according to an embodiment of the present invention.
2, the active wireless tag 11 in FIG. 1 includes a microcomputer 21 that performs overall control, an RF transmission circuit 28 that performs wireless transmission, and a battery 27 that supplies power to the microcomputer 21 and the RF transmission circuit 28. Is provided.
Here, the microcomputer 21 includes a ROM 22 that stores programs and data for executing processing performed by the active wireless tag 11, a RAM 23 that secures a work area performed by the CPU 25, a timer 24 that sets a transmission interval, a baud rate, and the like. An IO port 26 that provides a communication interface with the CPU 25 and the RF transmission circuit 28 for performing various arithmetic processes is provided. In addition, the RF transmission circuit 28 can transmit the radio wave R1 including the ID data, and can transmit the radio wave R2 that is weaker than the radio wave R1 immediately after the radio wave R1 is transmitted.

FIG. 3 is a block diagram showing a schematic configuration of a receiver according to an embodiment of the present invention.
In FIG. 3, the receivers 12 a to 12 d in FIG. 1 include a microcomputer 31 that performs overall control, an RF reception circuit 39 that performs wireless reception, and a radio wave intensity that measures the strength of radio waves received by the RF reception circuit 39. The measurement circuit 40, the serial communication circuit 41 for performing serial communication with the personal computer 13, the microcomputer 31, the RF reception circuit 39, the power supply circuit 38 for supplying power to the serial communication circuit 41, and the AC output supplied from the outlet. An AC adapter 37 that outputs to the power supply circuit 38 is provided.

  Here, the microcomputer 31 is set with a ROM 32 for storing a program or data for executing processing performed by each of the receivers 12a to 12d, a RAM 33 for securing a work area performed by the CPU 35, and a baud rate such as serial communication. A timer 34, a CPU 35 for performing various arithmetic processes, an RF receiving circuit 39, an IO port 36 for providing a communication interface among the radio wave intensity measuring circuit 40 and the serial communication circuit 41 are provided.

  Further, the RF receiving circuit 39 can receive the radio wave R1 including the ID data transmitted from the active radio tag 11 of FIG. 1 and the radio wave R2 having a low intensity transmitted immediately after the radio wave R1. The radio wave intensity measuring circuit 40 can measure the intensity of the radio wave R1 including the ID data received by the RF receiving circuit 39 and the radio wave R2 transmitted immediately thereafter. Further, the serial communication circuit 41 transmits the intensity of the radio wave R1 including the ID data measured by the radio wave intensity measurement circuit 40 and the intensity of the radio wave R2 immediately after that to the personal computer 13 together with the ID data of the active wireless tag 11. be able to.

FIG. 4 is a flowchart showing an operation of the active wireless tag according to the embodiment of the present invention.
In FIG. 4, after performing the initial process (step S11), the microcomputer 21 of FIG. 2 starts the timer 24 and waits for a fixed period (step S12). Then, when a certain time has elapsed (step S13), the microcomputer 21 causes the RF transmission circuit 28 to transmit the radio wave R1 including its own ID data (step S14). Is transmitted to the RF transmission circuit 28 (step S15).

  When the radio waves R1 and R2 are transmitted to the RF transmission circuit 28, the process returns to step S12, and the above operations are repeated to transmit the radio waves R1 and R2 to the receivers 12a to 12d at regular intervals. Note that, if the transmission interval of the radio waves R1 and R2 is shortened, the movement position of the active wireless tag 11 can be specified with high accuracy, but the battery 27 is consumed quickly. For this reason, the transmission intervals of the radio waves R1 and R2 can be set according to the moving speed of the active wireless tag 11, and the transmission intervals of the radio waves R1 and R2 are reduced as the moving speed of the active wireless tag 11 increases. Can do. For example, when grasping the labor situation of a nurse in a hospital, the interval between moving rooms can be assumed to be about 10 seconds, so the transmission intervals of radio waves R1 and R2 are set to 1 to 2 seconds. can do.

FIG. 5 is a flowchart showing the operation of the receiver according to the embodiment of the present invention.
In FIG. 5, after performing the initial process (step S21), the microcomputer 31 of FIG. 3 measures the radio field intensity of the radio wave R1 by the radio field intensity measurement circuit 40 (step S22), and the active radio tag 11 of FIG. The radio wave R1 including the ID data and the radio wave R2 immediately after that are received via the RF receiving circuit 39 (step S23). When confirming the reception of the ID data, the microcomputer 31 stores the ID data and the radio wave intensity 1 of the radio wave R1 in the RAM 33 (step S24).

Subsequently, the microcomputer 31 causes the radio field intensity measurement circuit 40 to measure the radio field intensity of the radio wave R2 (step S25), and stores the radio field intensity 2 of the radio wave R2 in the RAM 33 (step S26). The microcomputer 31 uses the serial communication circuit 41 to display the intensity 1 of the radio wave R1 including the ID data measured by the radio wave intensity measurement circuit 40 and the intensity 2 of the radio wave R2 immediately after that, together with the ID data of the active wireless tag 11. To the microcomputer 31 (step S27).
And if the intensity | strength 1, 2 and ID data of each radio wave R1, R2 are transmitted to the serial communication circuit 41, it will return to step S22 and the radio | wireless R1 transmitted from the active radio | wireless tag 11 by repeating the above operation | movement, R2 is received at regular intervals.

FIG. 6 is a flowchart showing the operation of the personal computer according to the embodiment of the present invention.
In FIG. 6, when the personal computer 13 of FIG. 1 serially receives the intensities 1 and 2 and ID data of the radio waves R1 and R2 from the receivers 12a to 12d (step S31), the ID data is stored (step S32). .
Subsequently, it is determined whether or not the intensity 1 of the radio wave R1 including the ID data received by each of the receivers 12a to 12d is saturated (step S33), and the intensity 1 of the radio wave R1 including the ID data is saturated. If not, the position of the active wireless tag 11 is detected by calculating the distance between each of the receivers 12a to 12d and the active wireless tag 11 based on the intensity 1 of the radio wave R1 including the ID data ( Step S34).

On the other hand, when the intensity 1 of the radio wave R1 including the ID data received by the receivers 12a to 12d is saturated, the personal computer 13 determines the intensity of the radio wave R2 transmitted immediately after the radio wave R1 including the ID data. By multiplying 2 by a predetermined coefficient, the distance between each of the receivers 12a to 12d and the active wireless tag 11 is calculated, and the position of the active wireless tag 11 is detected (step S35).
Then, the personal computer 13 compares the distances between the receivers 12a to 12d and the active wireless tag 11 calculated (step S36), and the receiver 12a having the closest distance to the active wireless tag 11 is compared. The position from ˜12d and the ID data of the active wireless tag 11 are displayed (step S37).

1A is a block diagram showing a schematic configuration of a position detection system according to an embodiment of the present invention, FIG. 1B is a diagram showing a configuration of radio data transmitted from an active radio tag, and FIG. (C) is a figure which shows the relationship between the radio wave intensity | strength of the radio | wireless data transmitted from an active radio | wireless tag, and the distance from an active radio | wireless tag. It is a block diagram showing a schematic structure of an active radio tag concerning one embodiment of the present invention. It is a block diagram which shows schematic structure of the receiver which concerns on one Embodiment of this invention. 3 is a flowchart illustrating an operation of an active wireless tag according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the receiver which concerns on one Embodiment of this invention. It is a flowchart which shows operation | movement of the personal computer which concerns on one Embodiment of this invention.

Explanation of symbols

11 Active wireless tag 12a to 12d Receiver 13 Personal computer 21, 31 Microcomputer 22, 32 ROM
23, 33 RAM
24, 34 Timer 25, 35 CPU
26, 36 IO port 27 Battery 28 RF transmitter circuit 37 AC adapter 38 Power supply circuit 39 RF receiver circuit 40 Radio wave intensity measurement circuit 41 Serial communication circuit

Claims (4)

First wireless transmission means for wirelessly transmitting ID data for identifying itself when a predetermined period or a predetermined condition is satisfied;
An active wireless tag comprising: a second wireless transmission unit configured to transmit a radio wave having a weaker intensity than a radio wave at the time of transmission of the ID data immediately after the transmission of the ID data. Radio receiving means for receiving a radio wave including ID data transmitted from an active radio tag and a radio wave having a weaker intensity than a radio wave transmitted immediately after the ID data is transmitted;
Radio wave intensity measuring means for measuring the intensity of the radio wave received by the radio receiving means;
A radio receiving apparatus comprising: communication means for transmitting the intensity of a radio wave including ID data measured by the radio wave intensity measuring means and the intensity of a radio wave immediately after the ID data together with the ID data. Receiving means for receiving, together with the ID data, the intensity of the radio wave including the ID data transmitted from the active wireless tag and the intensity of the radio wave weaker than that of the ID data transmitted immediately thereafter;
Saturation determination means for determining whether the intensity of the radio wave including the ID data transmitted from the active wireless tag is saturated;
First position detection means for detecting the position of the active wireless tag based on the strength of the radio wave including the ID data when the intensity of the radio wave including the ID data transmitted from the active wireless tag is not saturated;
When the intensity of the radio wave including ID data transmitted from the active radio tag is saturated, the position of the active radio tag is detected based on the intensity of the radio wave transmitted immediately after the radio wave including the ID data. A position detection device comprising: 2 position detection means. An active wireless tag that transmits a radio wave that is weaker than the radio wave at the time of transmission of the ID data immediately after transmission of the ID data for identifying itself;
A radio wave including ID data transmitted from the active wireless tag and a weak radio wave transmitted immediately thereafter are received, and the intensity of the radio wave including the ID data and the radio wave intensity immediately thereafter are transmitted together with the ID data. A radio,
A position for detecting the position of the active wireless tag based on the strength of the radio wave transmitted immediately after the radio wave including the ID data when the strength of the radio wave including the ID data received by the wireless device is saturated A position detection system comprising: a detection device.

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