JP2005098958A - Transceiving system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transceiving system capable of specifying the position of a transmitter, even under a circumstance where a radio wave is reflection or diffraction. <P>SOLUTION: This transceiving system 100 is provided with the transmitter 10, an array antenna 20, and a receiver 30. The transmitter 10 transmits omnidirectional radio waves via an antenna 11. The receiver 30 changes the directivity of the array antenna 20 into a plurality of numbers, by changing the patterns for turning on/off antenna elements 21-27 of the array antenna 20, receives the radio wave from the transmitter 10 via the array antenna 20 and detects the intensities of the plurality of received radio waves. The receiver 30 generates reception signal profiles indicating the intensity profiles of the plurality of radio waves, and computes the correlation coefficient between the plurality of received radio waves and a position signal profile indicating each position of the transmitter 10 measured in advance. The receiver 30 determines a position where the correlation coefficient gets maximum as the position of the transmitter 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transmission / reception system capable of specifying the position of a transmitter.

  Conventionally, a system that detects the position of a terminal using a radio wave from a GPS (Global Positioning System) satellite is known (Non-Patent Document 1). This system consists of receiving hardware and data analysis software. The reception hardware continuously receives signals from a plurality of GPS satellites, and calculates carrier phase range data from the reconstructed carrier phase data and code clock. Further, the data analysis software calculates the relative position and the accurate satellite orbit between the plurality of receiving hardware from the carrier phase range data obtained by the plurality of receiving hardware.

  A method for identifying the position of a transmitter by triangulation using two terminals is also known. The method using triangulation includes a method of determining the position of the transmitter by measuring an angle between the two terminals and the transmitter, and a distance between each terminal and the transmitter using the two terminals. There is a method to determine the position of the transmitter by measuring.

  Furthermore, a system that detects the position of a terminal indoors using a wireless LAN (Local Area Network) is also known (Non-Patent Document 2). This system includes a server, a plurality of access points, and a terminal. The server and the plurality of access points are connected to the LAN network. The terminal communicates with a plurality of access points. Of the plurality of access points, an access point associated with a terminal is a master access point, and three or more slave access points are provided for one master access point.

  The server requests the terminal to transmit a signal via the master access point. Each slave access point receives a signal from the terminal and transmits the received signal and the reception time of the signal to the server. The server calculates a time difference of arrival (TDOA) from the terminal to each slave based on the signal and time information received from each slave, and substitutes the calculated TDOA into the following simultaneous equations. To calculate the terminal position X.

| Z-Zi | --Z-Z1 | = c (Ti-T1), i = 1, 2,..., N
Where Z1, Z2,..., Zn represent the position of each slave access point, T1, T2,..., Tn represent the reception time of the terminal signal at each slave access point, and c is The speed of light.
YUJI SUGIMOTO, NORIYUKI KURIHARA, HITOSHI KIUCHI, AKIHIRO KANEKO, FUMITAKE SAWADA, FUMITAKE SAWADA System Prestar (Development of GPS Positioning System "PRESTAR"), IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, 38 (Vol.38), No2, April 1989, p.644-647 Kanno et al., "Wireless LAN Integrated Access System (1)-Examination of Position Detection System", 2003 IEICE General Conference, B-5-203, pp. 662, March 2003

  However, the method using GPS has a problem that the position of the transmitter cannot be specified indoors and underground malls because radio waves from GPS satellites are weak.

  In addition, the method using triangulation and the method using wireless LAN require a plurality of terminals, and there is a problem that the performance deteriorates when there is reflection of radio waves by walls and diffraction of radio waves by obstacles.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a transmission / reception system capable of specifying the position of a transmitter even in an environment in which radio waves are reflected or diffracted.

  According to the present invention, the transmission / reception system includes a transmitter and a receiver. The transmitter transmits radio waves. The receiver receives radio waves from the transmitter via an antenna whose directivity can be electrically switched. The receiver identifies the position of the transmitter by comparing the received signal profile indicating the intensity profile of multiple received radio waves received by changing the antenna directivity multiple times with the reference signal profile indicating each position of the transmitter. To do.

  Preferably, the transmitter transmits radio waves via another antenna capable of transmitting omnidirectional radio waves.

  Preferably, the transmitter transmits a radio wave via another antenna set to a predetermined directivity.

  According to the present invention, the transmission / reception system includes a transmitter and a receiver. The transmitter transmits radio waves via an antenna whose directivity can be electrically switched. The receiver receives radio waves from the transmitter. The receiver receives the radio wave transmitted by changing the antenna directivity a plurality of times, and the received signal profile indicating the intensity profile of the received plurality of received radio waves and the reference signal profile indicating each position of the transmitter The position of the transmitter is specified by comparison.

  Preferably, the receiver receives radio waves from the transmitter via another antenna capable of receiving omnidirectional radio waves.

  Preferably, the receiver receives a radio wave from the transmitter via another antenna set to a predetermined directivity.

  Preferably, the receiver receives a radio wave from the transmitter via another antenna capable of electrically switching directivity.

  Preferably, the reference signal profile is composed of a plurality of position signal profiles indicating each position of the transmitter. Then, the receiver calculates a correlation coefficient between the received signal profile and each of the plurality of position signal profiles, and specifies a position corresponding to the position signal profile having the maximum correlation coefficient as the position of the transmitter.

  Preferably, the receiver includes a receiver, a profile holder, a correlation calculator, and a maximum value detector. The receiver converts the received radio wave into a received signal profile. The profile holder holds a plurality of position signal profiles in association with a plurality of position information, and sequentially outputs each position signal profile and position information corresponding to the position signal profile. The correlation calculator calculates a correlation coefficient between the received signal profile from the receiver and the position signal profile from the profile holder, and outputs the calculated correlation coefficient. The maximum value detector detects the position information having the maximum correlation coefficient based on the position information from the profile holder and the correlation coefficient from the correlation calculator, and uses the detected position information as the position of the transmitter. As specified.

  Preferably, the plurality of position signal profiles are profiles measured by fixing one of the transmitter and the receiver and moving the other.

  Preferably, the plurality of position signal profiles includes a plurality of first and second position signal profiles. The plurality of first position signal profiles are profiles that are measured in advance by changing the directivity of the antenna to a plurality by the first pattern. The plurality of second position signal profiles are profiles measured in advance by changing the antenna directivity to a plurality of second patterns different from the first pattern. The receiver calculates the first correlation coefficient between the first received signal profile and each of the plurality of first position signal profiles when the directivity of the antenna is changed to a plurality by the first pattern. When a plurality of maximum values are detected from the first correlation coefficient, a second received signal profile is generated when the directivity is changed to a plurality by the second pattern, and the generated second reception is generated. A second correlation coefficient between the signal profile and each of the plurality of second position signal profiles is calculated to determine the position of the transmitter.

  Preferably, the receiver specifies, as a transmitter position, position information that matches position information corresponding to the maximum value of the second correlation coefficient among a plurality of position information corresponding to the plurality of maximum values.

  Preferably, each of the received signal profile and the plurality of position signal profiles includes a real part and an imaginary part. Then, the receiver calculates a correlation coefficient between the received signal profile and each of the plurality of position signal profiles using the real part and the imaginary part, and transmits a position corresponding to the position signal profile having the maximum correlation coefficient. Specify the position of the machine.

  Preferably, the antenna has a plurality of antenna elements, a control voltage generation circuit that generates a control voltage pattern for changing the directivity of the antenna, and a directivity by the plurality of antenna elements according to the control voltage pattern from the control voltage generation circuit. And a directivity changer for changing the sex to plural.

  Preferably, the antenna is an antenna whose directivity can be switched by reactance.

  In the transmission / reception system according to the present invention, a radio signal from a transmitter is received with a plurality of directivities changed, a received signal profile indicating an intensity profile of the received plurality of radio waves, and each position of the transmitter measured in advance. A correlation coefficient with a reference signal profile indicating Then, the position where the correlation coefficient is maximized is specified as the position of the transmitter.

  Therefore, according to the present invention, the position of the transmitter can be specified even in an environment where radio waves from the transmitter are reflected and diffracted.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a schematic diagram of a transmission / reception system according to Embodiment 1 of the present invention. The transmission / reception system 100 includes a transmitter 10, an array antenna 20, and a receiver 30. The transmission / reception system 100 is installed indoors, for example, in one room 50.

  The transmitter 10 includes an antenna 11. The antenna 11 is an omnidirectional antenna (omni antenna). Then, the transmitter 10 transmits, for example, a radio wave having a carrier frequency of 2.484 GHz via the antenna 11.

  Since the antenna 11 is an omnidirectional antenna, the radio wave transmitted from the antenna 11 propagates in all directions. The radio wave RW1 propagates directly from the antenna 11 toward the array antenna 20 of the receiver 30. The radio wave RW2 propagates from the antenna 11 toward the wall 51, is reflected by the wall 51, and then propagates toward the array antenna 20 of the receiver 30. Further, the radio wave RW3 propagates from the antenna 11 toward the wall 52, is reflected by the wall 52, and then propagates toward the array antenna 20 of the receiver 30. Further, the radio wave RW4 propagates from the antenna 11 toward the floor 53, is reflected by the floor, and then propagates toward the array antenna 20 of the receiver 30. Furthermore, the radio wave transmitted from the antenna 11 is reflected by the ceiling (not shown), propagates in the direction of the receiver 30, and is diffracted by an obstacle (not shown). Propagate in the direction.

  As described above, the radio wave emitted from the antenna 11 directly propagates in the direction of the receiver 30, and is reflected by the walls 51, 52, the floor 53 and the ceiling, and diffracted by the obstacle, and is directed to the array antenna 20. Propagate.

  The array antenna 20 includes antenna elements 21 to 27. The antenna elements 21 to 23 and 25 to 27 are parasitic elements, and the antenna element 24 is a feed element. The parasitic elements 21 to 23 and 25 to 27 are loaded with varactor diodes, which are variable capacitance elements. The array antenna 20 changes directivity by controlling the DC voltage applied to the varactor diodes. . That is, the array antenna 20 is an antenna whose directivity can be switched by reactance. That is, the array antenna 20 is an antenna capable of electrically switching directivity. The array antenna 20 is attached to the receiver 30 and receives radio waves RW1 to RW4 including direct waves, reflected waves and diffracted waves transmitted from the transmitter 10 with a predetermined directivity, and receives the received radio waves. Supply to machine 30.

  The receiver 30 specifies the position Ri (xi, yi, zi) (i: 1 to n, n is a natural number) of the transmitter 10 based on the radio wave from the array antenna 20 by a method described later. The position Ri (xi, yi, zi) represents each position of the transmitter 10 in the room 50 by xyz orthogonal coordinates.

  FIG. 2 is a schematic block diagram of the receiver 30 shown in FIG. The receiver 30 is loaded on a receiver 31, a correlation calculator 32, a profile holder 33, a maximum value detector 34, a control voltage generation circuit 35, and parasitic elements 21 to 23 and 25 to 27, respectively. Varactor diode 36.

  The receiver 31 receives a plurality of radio waves received by the array antenna 20 from the array antenna 20 by changing the directivity to a plurality (also referred to as “multiple times”, the same shall apply hereinafter). The receiver 31 sequentially detects the intensities of the plurality of radio waves, generates a received signal intensity profile RSSI indicating the intensity profiles of the plurality of radio waves, and outputs the received signal intensity profile RSSI to the correlation calculator 32.

  Correlation calculator 32 receives position signal intensity profiles PST1 to PSTn from profile holder 33. Each of the position signal strength profiles PST1 to PSTn is directed to the directivity of the array antenna 20 when the transmitter 10 is present at positions R1 (x1, y1, z1) to Rn (xn, yn, zn) of the room 50, respectively. It is an intensity profile of a plurality of radio waves received by changing to a plurality. Then, the correlation calculator 32 calculates correlation coefficients ρ1 to ρn between the received signal strength profile RSSI from the receiver 31 and the position signal strength profiles PST1 to PSTn from the profile holder 33 by a method described later, and the calculation The correlation coefficients ρ1 to ρn thus output are output to the maximum value detector 34.

  Profile holder 33 holds position signal intensity profiles PST1 to PSTn corresponding to positions R1 to Rn in room 50 of transmitter 10. Then, the profile holder 33 sequentially outputs the position signal intensity profiles PST1 to PSTn to the correlation calculator 32, and sequentially outputs the positions R1 to Rn to the maximum value detector 34. That is, when the profile holder 33 outputs the position signal intensity profile PST1 to the correlation calculator 32, the profile holder 33 outputs the position R1 corresponding to the position signal intensity profile PST1 to the maximum value detector 34. Thereafter, similarly, the profile holder 33 sequentially outputs the position signal intensity profiles PST2 to PSTn to the correlation calculator 32, and sequentially outputs the positions R2 to Rn to the maximum value detector 34.

  The maximum value detector 34 sequentially receives the correlation coefficients ρ1 to ρn from the correlation calculator 32 and sequentially receives the positions R1 to Rn from the profile holder 33. Then, the maximum value detector 34 detects the maximum value ρmax from the correlation coefficients ρ1 to ρn, and extracts a position corresponding to the detected maximum value ρmax from the positions R1 to Rn. For example, when the maximum value detector 34 detects the correlation coefficient ρ5 as the maximum value ρmax, the maximum value detector 34 extracts the position R5 as a position corresponding to the maximum value ρmax. When the maximum value detector 34 extracts the position corresponding to the maximum value ρmax, the maximum value detector 34 specifies the extracted position as the position of the transmitter 10.

  The control voltage generation circuit 35 sequentially generates control voltages CLV1 to CLVs (s is a natural number), and sequentially outputs the generated control voltages CLV1 to CLVs to the varactor diode 36. The varactor diode 36 sequentially changes the directivity of the antenna elements 21 to 27 of the array antenna 20 by changing the reactance value according to the control voltages CLV1 to CLVs. That is, the varactor diode 36 sequentially changes the directivity of the array antenna 20 to a plurality of numbers according to the control voltages CLV1 to CLVs.

  FIG. 3 is a conceptual diagram of the received signal strength profile RSSI. The control voltage generation circuit 35 sequentially generates control voltages CLV1 to CLVs each consisting of voltages V1 to V7 and outputs them to the varactor diode 36. In this case, the voltages V1 to V7 are voltages for changing reactance values loaded on the antenna elements 21 to 27, respectively, and can be changed in the range of 0 to 20V.

  The varactor diode 36 sets the directivity of the array antenna 20 to one directivity according to the control voltage CLV1 composed of the pattern P1. The array antenna 20 receives the radio wave from the transmitter 10 with the set directivity and supplies it to the receiver 31. The receiver 31 detects the intensity WI1 of the radio wave supplied from the array antenna 20.

  Next, the varactor diode 36 sets the directivity of the array antenna 20 to another directivity according to the control voltage CLV2 composed of the pattern P2. The array antenna 20 receives the radio wave from the transmitter 10 with the set directivity and supplies it to the receiver 31. The receiver 31 detects the intensity WI2 of the radio wave supplied from the array antenna 20.

  Thereafter, similarly, the varactor diode 36 sequentially changes the directivity of the array antenna 20 according to the control voltages CLV3 to CLVs composed of the patterns P3 to Ps, respectively. The array antenna 20 receives the radio wave from the transmitter 10 with the set directivity and supplies it to the receiver 31. The receiver 31 sequentially detects the strengths WI <b> 3 to WIs of the radio waves supplied from the array antenna 20.

  Then, the receiver 31 generates a received signal intensity profile RSSI indicating an intensity profile composed of the intensity WI <b> 1 to WIs, and outputs the received signal intensity profile RSSI to the correlation calculator 32.

  Note that the order of the patterns P1 to Ps is determined in advance. Therefore, the control voltage generation circuit 35 sequentially generates the control voltages CLV1 to CLVs in the order of the patterns P1 to Ps and outputs them to the varactor diode 36.

  As described above, when the directivity of the array antenna 20 is changed to a plurality of values, a received signal strength profile RSSI including a predetermined strength profile is obtained.

  FIG. 4 is a conceptual diagram of a position signal intensity profile. The position signal intensity profile PST1 is a plurality of radio waves received by sequentially changing the directivity of the array antenna 20 according to the control voltages CLV1 to CLVs when the transmitter 10 exists at the position R1 (x1, y1, z1) of the room 50. It is an intensity profile. Hereinafter, similarly, the position signal strength profiles PST2 to PSTn are obtained when the transmitter 10 exists at positions R2 (x2, y2, z2) to Rn (xn, yn, zn) of the room 50, respectively. Are the intensity profiles of a plurality of radio waves received by sequentially changing the directivity of the signals by the control voltages CLV1 to CLVs.

  Therefore, when the transmitter 10 exists at the position Ri (any one of the positions R1 to Rn), the receiver 31 detects the intensity of a plurality of radio waves from the array antenna 20 and detects the position signal intensity profile PSTi (position signal intensity). Any one of profiles PST1 to PSTn) is generated. As a result, the position signal intensity profiles PST1 to PSTn mean intensity profiles indicating the respective positions R1 to Rn of the transmitter 10.

  Note that the receiver 30 may be fixed and the transmitter 10 may be sequentially moved to each of the positions R1 to Rn to measure a plurality of position signal strength profiles PST1 to PSTn. May be sequentially moved to each of the positions R1 to Rn to measure the position signal intensity profiles PST1 to PSTn. That is, in the present invention, either one of the transmitter 10 and the receiver 30 may be fixed and the other may be moved to measure the position signal strength profiles PST1 to PSTn.

  The profile holder 33 holds the position signal intensity profiles PST1 to PSTn measured in advance in association with the positions R1 to Rn. Then, the profile holder 33 sequentially outputs the position signal intensity profiles PST1 to PSTn to the correlation calculator 32, and sequentially outputs the positions R1 to Rn to the maximum value detector 34.

  The correlation calculator 32 calculates correlation coefficients ρ1 to ρn between the received signal strength profile RSSI and the position signal strength profiles PST1 to PSTn according to the following equations.

ρi = | <R> · <Pi> | / (| <R> | × | <Pi> |) (1)
However, i = 1 to n.

In equation (1), <R> means a vector representation of the received signal strength profile RSSI, and <R> = [r1, r2,..., Rs)] ^T. <Pi> means a vector display of each of the position signal intensity profiles PST1 to PSTn, and <Pi> = [p1, p2,..., Ps] ^T. [R1, r2,..., Rs)] ^T and [p1, p2,..., Ps] ^T are the vectors [r1, r2,..., Rs)] and [p1, p2 respectively. ,..., Ps] represents a transposed vector.

  When calculating the correlation coefficient ρi according to the equation (1), the strengths WI1 to WIs constituting the received signal strength profile RSSI shown in FIG. 3 are elements r1 to rs, and the position signal strength profiles PST1 to PSTn shown in FIG. Let s intensities constituting the element be elements p1 to ps.

  FIG. 5 is a relationship diagram between the correlation coefficient ρi calculated by the equation (1) and the positions R1 to Rn of the transmitter 10. The maximum value detector 34 receives the correlation coefficients ρ1 to ρn from the correlation calculator 32 and receives the positions R1 to Rn from the profile holder 33. For example, the correlation coefficients ρ1 to ρn have the relationship shown in FIG. 5 with the positions R1 to Rn. The maximum value detector 34 detects the correlation coefficient ρ5 as the maximum value of the correlation coefficients ρ1 to ρn, and extracts the position R5 corresponding to the detected correlation coefficient ρ5. Then, the maximum value detector 34 sets the extracted position R5 as the position in the room 50 of the transmitter 10.

  Since the correlation coefficient ρi can take a value in the range of 0 to 1, the maximum value of the correlation coefficient ρi is “1”. As is clear from the equation (1), the correlation coefficient ρi is obtained by calculating the inner product of the vector <R> and the vector <Pi>. Therefore, when the vector <R> matches the vector <Pi>, the correlation coefficient ρi is maximized. This means that the received signal strength profile RSSI matches the position signal strength profile PSTi (any of PST1 to PSTn).

  Even if the two profiles do not completely match, the correlation coefficient ρi will be larger if one profile is closer to the other profile.

  Therefore, in the present invention, the received signal strength is calculated by calculating the correlation coefficient ρi (i: 1 to n) by the equation (1) and detecting the maximum value of the correlation coefficient ρi (i: 1 to n). Position signal intensity profiles closer to the profile RSSI are extracted from the position signal intensity profiles PST1 to PSTn. Since each of the position signal strength profiles PST1 to PSTn represents each position R1 to Rn in the room 50 of the transmitter 10 as described above, if a position signal strength profile closer to the received signal strength profile RSSI is extracted, the transmitter 10 The position in the room 50 can be specified.

  That is, the received signal strength profile RSSI and the position signal strength profiles PST1 to PSTn are generated by the array antenna 20 by the same control voltage patterns CLV1, CLV2,..., CLVs (sequentially generated according to the patterns P1 to Ps shown in FIG. Since the profile is measured by sequentially changing the directivity, if the transmitter 10 exists at the position Ri (xi, yi, zi) of the room 50, the receiver 31 receives the signal that matches the position signal intensity profile PSTi. A received signal strength profile RSSI approximate to the signal strength profile RSSI or the position signal strength profile PSTi is generated. Therefore, if the maximum value ρmax is detected from the correlation coefficients ρ1 to ρn, the position corresponding to the maximum value ρmax becomes the position of the transmitter 10.

  FIG. 6 is a flowchart for explaining the operation of specifying the position of transmitter 10 in receiver 30 shown in FIG. When a series of operations is started, the control voltage generation circuit 35 sequentially generates control voltages CLV1 to CLVs and outputs them to the varactor diode 36. The varactor diode 36 sequentially changes the directivity of the array antenna 20 to a plurality of in accordance with the control voltages CLV1 to CLVs, and the array antenna 20 receives radio waves from the transmitter 10 with each directivity (step S1). ), And supplies the received radio wave to the receiver 31.

  The receiver 31 sequentially detects the intensity of a plurality of radio waves supplied from the array antenna 20, and generates a received signal intensity profile RSSI indicating the intensity profile of the plurality of radio waves (step S2). Then, the receiver 31 outputs the generated received signal strength profile RSSI to the correlation calculator 32.

  Thereafter, the correlation calculator 32 sets k = 0 (step S3), and receives the position signal intensity profile PST1 from the profile holder 33 (step S4). When the correlation calculator 32 receives the position signal intensity profile PST1, it sets k = k + 1 (step S5). Then, the correlation calculator 32 calculates the correlation coefficient ρ1 between the received signal strength profile RSSI and the position signal strength profile PST1 using the equation (1) (step S6).

  When calculating the correlation coefficient ρ1, the correlation calculator 32 determines whether or not k = n (step S7). When k = n is not satisfied, the steps S4 to S6 are repeatedly executed until k = n. . That is, the correlation calculator 32 calculates the correlation coefficients ρ1 to ρn based on the received signal strength profile RSSI and the position signal strength profiles PST1 to PSTn. Then, the correlation calculator 32 outputs the calculated correlation coefficients ρ1 to ρn to the maximum value detector 34. The profile holder 33 sequentially outputs the positions R1 to Rn to the maximum value detector 34.

  If it is determined in step S7 that k = n, the maximum value detector 34 detects the maximum value ρmax from the correlation coefficients ρ1 to ρn (step S8), and sets the position corresponding to the maximum value ρmax to the transmitter. The position is specified as 10 (step S9). Thereby, a series of operation | movement is complete | finished.

  Note that the operation of specifying the position of the transmitter 10 in the receiver 30 is actually performed by a CPU (Central Processing Unit), and the CPU stores a program including each step shown in FIG. 6 in a ROM (Read Only Memory). , And the read program is executed to specify the position of the transmitter 10 according to the flowchart shown in FIG.

  Accordingly, the ROM corresponds to a computer (CPU) readable recording medium in which a program for causing a computer (CPU) to execute an operation for specifying the position of the transmitter 10 is recorded.

  Then, the program including the steps shown in FIG. 6 causes the computer (CPU) to specify the position of the transmitter 10 based on a plurality of radio waves received by sequentially changing the directivity of the array antenna 20 to a plurality. It is a program.

  Therefore, this program can cause the computer (CPU) to specify the position of the transmitter 10 even if the radio wave includes a reflected wave and a diffracted wave.

  The plurality of position signal intensity profiles PST1 to PSTn constitute a “reference signal profile”.

  Further, the positions R1 to Rn constitute “position information”.

  According to the first embodiment, the receiver 30 generates a received signal strength profile RSSI indicating the strength profiles of a plurality of radio waves received by the array antenna 20 by changing the directivity to a plurality, and the generated received signal strength. Based on the profile RSSI and position signal intensity profiles PST1 to PSTn indicating the respective positions R1 to Rn in the room 50 of the transmitter 10 measured in advance by receiving radio waves including reflected waves and diffracted waves from the transmitter 10. Thus, since the position of the transmitter 10 is specified by detecting the position signal intensity profile that matches the received signal intensity profile RSSI, the position of the transmitter 10 can be specified even in an environment where reflected waves and diffracted waves exist.

  Further, the position of the transmitter 10 can be specified by one terminal (receiver 30).

[Embodiment 2]
FIG. 7 is a schematic block diagram of a receiver in the second embodiment. In the transmission / reception system according to the second embodiment, the receiver 30 of the transmission / reception system 100 is replaced with a receiver 30A.

  The receiver 30A is obtained by replacing the maximum value detector 34 of the receiver 30 with the maximum value detector 34A, replacing the control voltage generating circuit 35 with the control voltage generating circuit 35A, and replacing the profile holder 33 with the profile holder 33A. Others are the same as those of the receiver 30.

  The profile holder 33A sequentially changes the directivity of the array antenna 20 in accordance with the position signal intensity profiles PST11 to PST1n measured by sequentially changing the directivity of the array antenna 20 according to the control voltages CLV11 to CLV1s, and the control voltages CLV21 to CLV2s. The measured position signal intensity profiles PST21 to PST2n are held in association with the positions R1 to Rn. The profile holder 33A sequentially outputs the position signal intensity profiles PST11 to PST1n to the correlation calculator 32. When the profile holder 33A receives the switching signal EXC1 from the maximum value detector 34A, the position calculator 33A converts the position signal intensity profiles PST21 to PST2n to the correlation calculator 32. Output sequentially.

  Position signal intensity profiles PST11 to PST1n and PST21 to PST2n are measured by the same method as that in the first embodiment.

  When there are two maximum values in the correlation coefficients ρ11 to ρ1n received from the correlation calculator 32, the maximum value detector 34A generates a switching signal EXC1 and outputs the switching signal EXC1 to the profile holder 33A. Generated and output to the control voltage generation circuit 35A. The switching signal EXC1 is a signal for switching the position signal intensity profile output to the correlation calculator 32 from the position signal intensity profiles PST11 to PST1n to the position signal intensity profiles PST21 to PST2n. The switching signal EXC2 is a signal for switching the pattern of the control voltage CLV output to the varactor diode 36. Further, when one maximum value exists in the correlation coefficients ρ11 to ρ1n received from the correlation calculator 32, the maximum value detector 34A specifies the position corresponding to the maximum value as the position of the transmitter 10. When there are two maximum values in the correlation coefficients ρ11 to ρ1n received from the correlation calculator 32, the maximum value detector 34A further increases from the correlation coefficients ρ21 to ρ2n received from the correlation calculator 32. A value is detected, and a position common to the maximum value detected from the correlation coefficients ρ11 to ρ1n and the maximum value detected from the correlation coefficients ρ21 to ρ2n is specified as the position of the transmitter 10.

  The control voltage generation circuit 35A sequentially generates control voltages CLV11 to CLV1s composed of the same patterns P11 to P1s as the patterns P1 to Ps described above and outputs them to the varactor diode 36. In addition, when receiving the switching signal EXC2 from the maximum value detector 34A, the control voltage generation circuit 35A sequentially generates control voltages CLV21 to CLV2s having patterns P21 to P2s different from the patterns P11 to P1s and outputs them to the varactor diode 36. .

  In the second embodiment, the varactor diode 36 sequentially changes the directivity of the array antenna 20 to a plurality according to the control voltages CLV11 to CLV1s and CLV21 to CLV2s.

  FIG. 8 is a conceptual diagram of a received signal strength profile in the second embodiment. The control voltage generation circuit 35A sequentially generates control voltages CLV11 to CLV1s composed of patterns P11 to P1s and outputs them to the varactor diode 36.

  The varactor diode 36 sequentially changes the directivity of the array antenna 20 into a plurality according to the control voltages CLV11 to CLV1s. The array antenna 20 receives radio waves from the transmitter 10 with each set directivity and supplies a plurality of radio waves to the receiver 31. The receiver 31 detects the intensity of a plurality of radio waves supplied from the array antenna 20 and generates a received signal intensity profile RSSI1.

  When receiving the switching signal EXC2 from the maximum value detector 34A, the control voltage generation circuit 35A sequentially generates control voltages CLV21 to CLV2s composed of patterns P21 to P2s and outputs them to the varactor diode 36.

  The varactor diode 36 sequentially changes the directivity of the array antenna 20 into a plurality according to the control voltages CLV21 to CLV2s. The array antenna 20 receives radio waves from the transmitter 10 with each set directivity and supplies a plurality of radio waves to the receiver 31. The receiver 31 detects the intensity of a plurality of radio waves supplied from the array antenna 20 and generates a received signal intensity profile RSSI2.

  In the second embodiment, the correlation calculator 32 calculates the correlation coefficients ρ11 to ρ1n by the above-described method based on the received signal strength profile RSSI1 and the position signal strength profiles PST11 to PST1n, and detects the maximum value. To 34A. Further, the correlation calculator 32 calculates the correlation coefficients ρ21 to ρ2n by the method described above based on the received signal strength profile RSSI2 and the position signal strength profiles PST21 to PST2n and outputs them to the maximum value detector 34A.

  FIG. 9 is another relationship diagram between the correlation coefficient ρmi (m = 1, 2) calculated by the equation (1) and the position of the transmitter 10. The maximum value detector 34A receives the correlation coefficients ρ11 to ρ1n from the correlation calculator 32 and receives the positions R1 to Rn from the profile holder 33.

  For example, the correlation coefficients ρ11 to ρ1n have the relationship shown in FIG. 8 with the positions R1 to Rn. The maximum value detector 34A detects the correlation coefficients ρ14 and ρ1k as the maximum values of the correlation coefficients ρ11 to ρ1n. That is, the maximum value detector 34A detects two maximum values ρ1max1 (= ρ14) and ρ1max2 (= ρ1k). When the maximum value detector 34A detects two maximum values ρ1max1 and ρ1max2, it generates a switching signal EXC1 and outputs it to the profile holder 33A, and generates a switching signal EXC2 and outputs it to the control voltage generation circuit 35A.

  When receiving the correlation coefficients ρ21 to ρ2n from the correlation calculator 32, the maximum value detector 34A detects the maximum value ρ2max (= ρ2k) from the correlation coefficients ρ21 to ρ2n. Then, the maximum value detector 34A extracts a position Rk common to the maximum values ρ1max1 (= ρ14), ρ1max2 (= ρ1k) and the maximum value ρ2max (= ρ2k), and uses the extracted position Rk of the transmitter 10. Specify as location.

  As described above, in the second embodiment, the correlation coefficients ρ11 to ρ1n calculated by receiving radio waves from the transmitter 10 while changing the directivity of the array antenna 20 to a plurality of patterns according to one pattern are two maximum values. , The directivity of the array antenna 20 is changed into a plurality of patterns according to another pattern, the radio waves from the transmitter 10 are received, the correlation coefficients ρ21 to ρ2n are calculated, and the correlation coefficients ρ11 to ρ1n and the correlation coefficient are calculated. The position of the transmitter 10 is specified based on ρ21 to ρ2n.

  FIG. 10 is a flowchart for explaining the operation of specifying the position of transmitter 10 in receiver 30A shown in FIG. When a series of operations is started, the control voltage generation circuit 35A sequentially generates the control voltages CLV11 to CLV1s according to the first pattern (patterns P11 to P1s) and outputs them to the varactor diode 36. Then, the varactor diode 36 sequentially changes the directivity of the array antenna 20 into a plurality according to the control voltages CLV11 to CLV1s.

  The array antenna 20 receives the radio wave from the transmitter 10 with each directivity (step S11) and supplies the received radio wave to the receiver 31. Then, the maximum value detector 34A sets m = 1 (step S12). The receiver 31 sequentially detects the intensity of a plurality of radio waves supplied from the array antenna 20 and generates a received signal intensity profile RSSI1 indicating the intensity profile of the plurality of radio waves (step S13). Then, the receiver 31 outputs the generated received signal strength profile RSSI1 to the correlation calculator 32.

  Thereafter, the correlation calculator 32 sets k = 0 (step S14), and receives the position signal intensity profile PST11 from the profile holder 33A (step S15). When the correlation calculator 32 receives the position signal intensity profile PST11, it sets k = k + 1 (step S16). Then, the correlation calculator 32 calculates the correlation coefficient ρ11 between the received signal strength profile RSSI1 and the position signal strength profile PST11 using the equation (1) (step S17).

  When calculating the correlation coefficient ρ11, the correlation calculator 32 determines whether or not k = n (step S18). When k = n is not satisfied, the steps S15 to S17 are repeatedly executed until k = n. . That is, the correlation calculator 32 calculates the correlation coefficients ρ11 to ρ1n based on the received signal strength profile RSSI1 and the position signal strength profiles PST11 to PST1n. Then, the correlation calculator 32 outputs the calculated correlation coefficients ρ11 to ρ1n to the maximum value detector 34A. Further, the profile holder 33A sequentially outputs the positions R1 to Rn to the maximum value detector 34A.

  If it is determined in step S18 that k = n, the maximum value detector 34A detects the maximum value ρ1max from the correlation coefficients ρ11 to ρ1n (step S19). Then, the maximum value detector 34A determines whether m = 2 (step S20), and when m = 2 is not satisfied, further determines whether the maximum value ρ1max detected in step S19 is two. (Step S21).

  When it is determined in step S21 that the maximum value ρ1max is two, the maximum value detector 34A sets m = m + 1 (step S22), generates the switching signal EXC1, and outputs it to the profile holder 33A. The switch signal EXC2 is generated and output to the control voltage generation circuit 35A.

  The profile holder 33A sequentially outputs the position signal intensity profiles PST21 to PST2n to the correlation calculator 32 in response to the switching signal EXC1 from the maximum value detector 34A. Further, the control voltage generation circuit 35A sequentially generates the control voltages CLV21 to CLV2s according to the second pattern (patterns P21 to P2s) according to the switching signal EXC2 from the maximum value detector 34A and outputs the control voltages CLV21 to CLV2s to the varactor diode 36. . Then, the varactor diode 36 sequentially changes the directivity of the array antenna 20 to a plurality according to the control voltages CLV21 to CLV2s.

  The array antenna 20 receives the radio wave from the transmitter 10 with each directivity (step S23), and supplies the received radio wave to the receiver 31. Thereafter, steps S13 to S19 are repeatedly executed. In this case, the correlation calculator 32 calculates the correlation coefficients ρ21 to ρ2n based on the received signal strength profile RSSI2 and the position signal strength profiles PST21 to PST2n and outputs the correlation coefficients ρ21 to ρ2n to the maximum value detector 34A. Detects the maximum value ρ2max from the correlation coefficients ρ21 to ρ2n.

  On the other hand, when it is determined in step S21 that the maximum value ρ1max is not two, the maximum value detector 34A specifies the position corresponding to the detected ρ1max as the position of the transmitter 10 (step S24).

  After step S13 to S19 are repeatedly executed, if it is determined in step S20 that m = 2, the maximum value detector 34A has a position R (ρ2max) corresponding to the maximum value ρ2max corresponding to the maximum value ρ1max1. It is determined which of the position R (ρ1max1) and the position R (ρ1max2) corresponding to the maximum value ρ1max2 is equal (step S25).

  When it is determined that the position R (ρ2max) corresponding to the maximum value ρ2max is equal to the position R (ρ1max1) corresponding to the maximum value ρ1max1, the maximum value detector 34A determines the position corresponding to the maximum values ρ1max1 and ρ2max. The position of the transmitter 10 is specified (step S26).

  On the other hand, when it is determined in step S25 that the position R (ρ2max) corresponding to the maximum value ρ2max is equal to the position R (ρ1max2) corresponding to the maximum value ρ1max2, the maximum value detector 34A sets the maximum values ρ1max2 and ρ2max to The corresponding position is specified as the position of the transmitter 10 (step S27).

  And after any of step S24, S26, S27, a series of operation | movement is complete | finished.

  Note that the operation of specifying the position of the transmitter 10 in the receiver 30A is actually performed by the CPU. The CPU reads a program including the steps shown in FIG. 10 from the ROM, and executes the read program. The position of the transmitter 10 is specified according to the flowchart shown in FIG.

  Accordingly, the ROM corresponds to a computer (CPU) readable recording medium in which a program for causing a computer (CPU) to execute an operation for specifying the position of the transmitter 10 is recorded.

  Then, the program including the steps shown in FIG. 10 has a plurality of maximum values in correlation coefficients calculated based on a plurality of radio waves received by sequentially changing the directivity of the array antenna 20 to a plurality of This is a program that causes a computer (CPU) to specify the position of the transmitter 10.

  Therefore, this program specifies the position of the transmitter 10 even when there are a plurality of maximum correlation coefficients calculated based on a plurality of radio waves including direct waves, reflected waves, and diffracted waves. It can be executed by a computer (CPU).

  According to the second embodiment, the phase difference between the received signal intensity profile of a plurality of radio waves received by sequentially changing the directivity of array antenna 20 into a plurality of patterns according to a certain pattern and the position signal intensity profile indicating each position of transmitter 10. When there are two maximum values in the relation numbers ρ11 to ρ1n, the received signal intensity profile and the position signal intensity profile of a plurality of radio waves received by sequentially changing the directivity of the array antenna 20 to a plurality of patterns according to another pattern The correlation coefficients ρ21 to ρ2n are calculated, and the position common to the position corresponding to the maximum value of the correlation coefficients ρ11 to ρ1n and the position corresponding to the maximum value of the correlation coefficients ρ21 to ρ2n is set as the position of the transmitter 10. Identify.

  Therefore, the position of the transmitter 10 can be specified even when there are a plurality of maximum values in the correlation coefficient.

  In the above description, the case where there are two maximum correlation coefficient values has been described, but the maximum value may be three or more.

  Further, when there are a plurality of maximum values in correlation coefficients ρ21 to ρ2n, the correlation coefficient may be calculated by sequentially changing the directivity of array antenna 20 to a plurality according to another control voltage pattern.

  Others are the same as in the first embodiment.

[Embodiment 3]
FIG. 11 is a schematic block diagram of a receiver in the third embodiment. In the transmission / reception system according to the third embodiment, the receiver 30 of the transmission / reception system 100 is replaced with a receiver 30B.

  Receiver 30B includes a receiver 31A, a correlation calculator 32A, a profile holder 33B, a maximum value detector 34B, a control voltage generation circuit 35, and a varactor diode 36. The control voltage generation circuit 35 and the varactor diode 36 are as described in the first embodiment.

  The receiver 31A detects a plurality of signals received by the array antenna 20 by changing the directivity to a plurality of parts into a real part and an imaginary part, and a real part received signal profile based on the detected real part intensity. RCV_I is generated, and an imaginary part received signal profile RCV_Q is generated based on the detected intensity of the imaginary part. Then, receiver 31A outputs real part received signal profile RCV_I and imaginary part received signal profile RCV_Q to correlation calculator 32A.

  The correlation calculator 32A sequentially receives the real part position signal profiles PST1_I to PSTn_I and the imaginary part position signal profiles PST1_Q to PSTn_Q from the profile holder 33B. Then, the correlation calculation unit 32A generates a complex vector <Rcp1> = <RCV_I> + j <RCV_Q> having the real part received signal profile RCV_I and the imaginary part received signal profile RCV_Q as real parts and imaginary parts, respectively.

Further, the correlation calculator 32A generates a complex vector <Pcp1> = <PSTi_I> + j <PSTi_Q> having the real part position signal profiles PST1_I to PSTn_I and the imaginary part position signal profiles PST1_Q to PSTn_Q as real parts and imaginary parts, respectively. . Then, the correlation calculator 32A calculates the complex conjugate transposed vector <Rcpl> ^H = <RCV_I> ^T −j <RCV_Q> ^T of the complex vector <Rcpl>, and calculates the complex vectors <Rcpl> ^H , <Rcpl> and <Pcpl. > Is substituted into the following equation to calculate the correlation coefficient ρcp1.

ρcpli = | <Rcpl> ^H · <Pcpl> | / (| <Rcpl> | × | <Pcpl> |) (2)
The profile holder 33B holds real part position signal profiles PST1_I to PSTn_I and imaginary part position signal profiles PST1_Q to PSTn_Q corresponding to the positions R1 to Rn in the room 50 of the transmitter 10. Then, the profile holder 33B outputs the real part position signal profile PST1_I and the imaginary part position signal profile PST1_Q to the correlation calculator 32A, and outputs the position R1 to the maximum value detector 34B. Similarly, the profile holder 33B sequentially outputs the real part position signal profiles PST2_I to PSTn_I and the imaginary part position signal profiles PST2_Q to PSTn_Q to the correlation calculator 32A, and outputs the positions R2 to Rn to the maximum value detector 34B. Output sequentially.

  The maximum value detector 34B detects the maximum value of the correlation coefficients ρcp11 to ρcpln based on the correlation coefficient ρcpli (i: 1 to n) from the correlation calculator 32A, and determines the position corresponding to the detected maximum value. The position of the transmitter 10 is specified.

  FIG. 12 is a conceptual diagram of a real part received signal profile and an imaginary part received signal profile. Control voltage generation circuit 35 sequentially generates control voltages CLV1 to CLVs according to patterns P1 to Ps and outputs them to varactor diode 36.

  The varactor diode 36 sets the directivity of the array antenna 20 to one directivity according to the control voltage CLV1 composed of the pattern P1. The array antenna 20 receives the radio wave from the transmitter 10 with the set directivity and supplies it to the receiver 31A. The receiver 31A detects the real part WI1_I and the imaginary part WI1_Q of the intensity of the radio wave supplied from the array antenna 20.

  Next, the varactor diode 36 sets the directivity of the array antenna 20 to another directivity according to the control voltage CLV2 composed of the pattern P2. The array antenna 20 receives the radio wave from the transmitter 10 with the set directivity and supplies it to the receiver 31A. The receiver 31A detects the real part WI2_I and the imaginary part WI2_Q of the intensity of the radio wave supplied from the array antenna 20.

  Thereafter, similarly, the varactor diode 36 sequentially changes the directivity of the array antenna 20 according to the control voltages CLV3 to CLVs composed of the patterns P3 to Ps, respectively. The array antenna 20 receives the radio wave from the transmitter 10 with the set directivity and supplies it to the receiver 31A. The receiver 31A sequentially detects the real part WI3_I to WIs_I and the imaginary part WI3_Q to WIs_Q of the intensity of the radio wave supplied from the array antenna 20.

  Then, the receiver 31A generates a real part received signal profile RCV_I composed of the strong real parts WI1_I to WIs_I and an imaginary part received signal profile RCV_Q composed of the strong imaginary parts WI1_Q to WIs_Q, and outputs them to the correlation calculator 32A. To do.

  FIG. 13 is a conceptual diagram of a real part position signal profile and an imaginary part position signal profile. The real part position signal profile PST1_I and the imaginary part position signal profile PST1_Q indicate the directivity of the array antenna 20 by the control voltages CLV1 to CLVs when the transmitter 10 exists at the position R1 (x1, y1, z1) of the room 50. It is a real part intensity profile and an imaginary part intensity profile of each of a plurality of radio waves received by changing sequentially. Hereinafter, similarly, the real part position signal profiles PST2_I to PSTn_I and the imaginary part position signal profiles PST2_Q to PSTn_Q are obtained from the transmitter 10 at positions R2 (x2, y2, z2) to Rn (xn, yn, zn) of the room 50, respectively. ) Are real part intensity profiles and imaginary part intensity profiles of a plurality of radio waves received by sequentially changing the directivity of the array antenna 20 according to the control voltages CLV1 to CLVs.

  The profile holder 33B holds the real part position signal profile PST1_I and the imaginary part position signal profile PST1_Q corresponding to the position R1. Hereinafter, similarly, the profile holder 33B corresponds to the positions R2 to Rn, respectively, and the real part position signal profile PST2_I, the imaginary part position signal profile PST2_Q, the real part position signal profile PSTn_I, and the imaginary part position signal profile PSTn_Q. Hold.

  Then, the profile holder 33B sequentially outputs the real part position signal profile PST1_I and the imaginary part position signal profile PST1_Q to the real part position signal profile PSTn_I and the imaginary part position signal profile PSTn_Q to the correlation calculator 32A, and outputs the positions R1 to Rn. The data is sequentially output to the maximum value detector 34B.

  The complex position signal profiles PST1_I to PSTn_I and PST1_Q to PSTn_Q are measured in advance by the same method as in the first embodiment.

  The operation of specifying the position of the transmitter 10 in the receiver 30B is performed according to the flowchart shown in FIG. In this case, the received signal profile and the position signal profile in steps S2, S4, and S6 are composed of a real part and an imaginary part as described above.

  As described above, in the third embodiment, the intensity profiles of a plurality of radio waves received by the array antenna 20 with different directivities are represented by complex vectors, so that the phase between the complex reception signal profile and the complex position signal profile is expressed. The number of relations can be calculated more accurately, and the position of the transmitter 10 can be specified more accurately.

  In the third embodiment, when there are a plurality of maximum values in the correlation coefficients ρcp1 to ρcpln calculated by the above-described method, the position of the transmitter 10 is specified by the method described in the second embodiment. May be.

  Others are the same as in the first embodiment.

  In the present invention, antenna elements 21 to 27, control voltage generating circuit 35 (or 35A), and varactor diode 36 constitute an “antenna” whose directivity can be electrically switched.

  In the above description, it has been described that the received signal strength profile RSSI is generated by the array antenna 20, the receiver 31, and the varactor diode 36. However, the present invention is not limited to this, and a plurality of antenna elements, switches, and receivers are used. A received signal strength profile RSSI may be generated. In this case, the switch sequentially switches connections with the plurality of antenna elements, and supplies the radio waves received by the antenna elements to the receiver.

  Further, the received signal strength profile RSSI may be generated by a plurality of antenna elements and a plurality of receivers. In this case, the plurality of receivers are provided corresponding to the plurality of antenna elements. Each receiver detects the intensity of the radio wave received by the corresponding antenna element and outputs it to the correlation calculators 32 and 32A.

  Further, the received signal strength profile RSSI may be generated by a plurality of antenna elements, a plurality of variable phase shifters, and an adder. In this case, the plurality of variable phase shifters are provided corresponding to the plurality of antenna elements, and receive radio waves by sequentially changing the phase pattern. The adder adds radio waves from a plurality of variable phase shifters to one phase pattern and outputs the result to the correlation calculators 32 and 32A.

  Further, in the above description, the array antenna 20 is mounted on the receiver 30 and the antenna 11 is mounted on the transmitter 10. However, the present invention is not limited to this, and the array antenna 20 is mounted on the transmitter. 10 and the antenna 11 may be attached to the receiver 30. That is, in the present invention, the array antenna 20 only needs to be attached to either the transmitter 10 or the receiver 30.

  Furthermore, in the present invention, the array antenna 20 may be attached to both the transmitter 10 and the receiver 30.

  Furthermore, in the above description, the transmission / reception system 100 is described as being installed in one room. However, the present invention is not limited to this, and the transmitter 10 and the receiver 30 may be installed in separate rooms. .

  Furthermore, the transmission / reception system 100 may be installed outdoors including a radio wave environment in which at least reflected waves and diffracted waves propagate.

  Hereinafter, experimental results for specifying the position of the transmitter 10 in the transmission / reception system 100 will be described. FIG. 14 shows the layout of the experimental environment. The room 60 used for the experiment is a room having a length of 11.95 m, a width of 9.6 m, and a height of 10 m. The room 60 includes walls 61 to 64, a floor 65, and a ceiling (not shown). A desk 41 and shelves 42 and 43 are arranged in an approximately half area of the room 60.

  In the experiment, an area where the desk 41 and the shelves 42 and 43 are not arranged is set as the position detection target area 70. The position detection target area 70 is a 3 m long and 5 m wide area. In the position detection target area 70, 416 measurement points were set at intervals of 0.2 m. The 416 measurement points are represented by the X coordinate and the Y coordinate, and the receiver 30 for specifying the position of the transmitter 10 is arranged at the position [20, 5]. In FIG. 14, the arrangement position of the receiver 30 is indicated by the array antenna 20.

  The transmitter 10 is equipped with an omni antenna as the antenna 11. The antenna 11 and the array antenna 20 were disposed at the same height of 1.2 m from the floor 65.

  Thus, since the desk 41 and the shelves 42 and 43 exist in the room 60 in which the transmitter 10 and the receiver 30 are arranged, the radio waves transmitted from the transmitter 10 are transmitted through the walls 61 to 64, the floor 65, and It is reflected by the ceiling and propagates to the receiver 30, and is diffracted by the desk 41 and the shelves 42 and 43 and propagates to the receiver 30.

  Therefore, the environment used for the experiment is an environment in which the radio wave transmitted from the transmitter 10 is received as a radio wave including a reflected wave and a diffracted wave.

  Transmitter 10 modulates a signal composed of an M-sequence PN code by BPSK (Binary Phase Shift Keying) modulation, and transmits the modulated signal at a carrier frequency of 2.484 GHz. The sequence length of the transmission signal was 1000 symbols and the symbol rate was 500 kHz. Further, symbol synchronization and carrier synchronization between transmission and reception are performed by cheating by connecting the transmitter 10 and the receiver 30 with a wire and transmitting and receiving a reference signal for synchronization.

  The directivity of the array antenna 20 was sequentially switched according to the patterns P1 to P7 shown in Table 1.

  Note that the patterns P1 to P7 shown in Table 1 include reactances R1 to R7 instead of the voltages V1 to V7 applied to the antenna elements 21 to 27 of the array antenna 20. Since the reactances R1 to R7 of the antenna elements 21 to 27 are changed by changing the voltages V1 to V7 applied to the antenna elements 21 to 27, the directivity of the array antenna 20 is changed by changing the reactances R1 to R7 of the antenna elements 21 to 27. You can change your gender.

  In the experiment, the reactance R4 of the antenna element 24 was fixed to 0Ω. Further, the transmitter 10 is installed at each measurement point shown in FIG. 14, and the directivity of the array antenna 20 is sequentially changed according to the patterns P1 to P7 shown in Table 1 to receive the radio wave from the transmitter 10 and the position signal intensity profile. PST1 to PSTn (including PST11 to PST1n and PST21 to PST2n) and complex position signal profiles PST1_I to PSTn_I and PST1_Q to PSTn_Q were created in advance.

  In the experiment, it was evaluated whether or not the position of the transmitter 10 can be accurately specified when the transmitter 10 is installed at the position [5, 10].

  FIG. 15 shows a correlation calculation result when the received signal strength profile RSSI in the first and second embodiments is used. FIG. 16 is a graph of the correlation coefficient ρ on the dotted line A-A ′ in FIG. 15. FIG. 17 shows a correlation calculation result when the complex received signal profile in the third embodiment is used. FIG. 18 is a graph of the correlation coefficient ρ ′ on the dotted line A-A ′ in FIG.

  Each correlation coefficient ρ in FIG. 15 is a received signal strength profile when transmitter 10 is installed at each measurement point shown in FIG. 14 and the directivity of array antenna 20 is sequentially changed according to patterns P1 to P7 shown in Table 1. This is a correlation coefficient between RSSI and position signal intensity profiles PST1 to PSTn.

  Further, the correlation coefficient ρ ′ in FIG. 17 is a complex reception when the transmitter 10 is installed at each measurement point shown in FIG. 14 and the directivity of the array antenna 20 is sequentially changed according to the patterns P1 to P7 shown in Table 1. This is a correlation coefficient between the signal profiles RCV_I and RCV_Q and the complex position signal profiles PST1_I to PSTn_I and PST1_Q to PSTn_Q.

  As shown in FIG. 16, when the received signal strength profile RSSI was used, the largest correlation coefficient ρ = 0.99 was obtained at the position [5, 10] where the transmitter 10 was placed. Further, as shown in FIG. 18, even when the complex reception signal profiles RCV_I and RCV_Q are used, the largest correlation coefficient ρ ′ = 0.99 is obtained at the position [5, 10] where the transmitter 10 is disposed. .

  From these results, the position detection method using the received signal strength profile RSSI and the position detection method using the complex received signal profiles RCV_I and RCV_Q can accurately specify the position of the transmitter 10 with an accuracy of 0.2 m or less. all right.

  15 and FIG. 17, when the received signal strength profile RSSI (FIG. 15) is used, the arrangement position of the transmitter 10 is greater than when the complex received signal profiles RCV_I and RCV_Q are used (FIG. 17). In many points other than [5, 10], the correlation coefficient ρ is large.

  Therefore, in the case of the position detection method using the received signal strength profile RSSI, the directivity of the array antenna 20 is set to a plurality of patterns P11 to P1s as described in the second embodiment in order not to erroneously detect the position of the transmitter 10. It is important that the received signal strength profile RSSI is created in accordance with P21 to P2s.

[Embodiment 4]
FIG. 19 is a schematic diagram of a transmission / reception system according to the fourth embodiment. The transmission / reception system 100A according to the fourth embodiment is the same as the transmission / reception system 100 except that the transmitter 10 of the transmission / reception system 100 shown in FIG.

  The transmitter 10A includes an antenna 11A. The antenna 11A is an antenna having directivity. Therefore, the radio wave RW5 transmitted from the antenna 11A propagates in the direction of the wall 52, is reflected by the wall 52, and then propagates in the direction of the receiver 30. The radio wave RW6 transmitted from the antenna 11A propagates in the direction of a wall (not shown) in front of the room 50, is reflected by the wall, and then propagates in the direction of the receiver 30. Furthermore, the radio wave RW7 transmitted from the antenna 11A propagates directly in the direction of the receiver 30.

  In FIG. 19, three radio waves RW5 to RW7 are shown as radio waves transmitted from the antenna 11A. However, depending on the directivity of the antenna 11A, a radio wave propagating in a different direction from the radio waves RW5 to RW7 may be transmitted. Sent from

  20 is a vertical sectional view of the antenna 11A shown in FIG. The antenna 11A includes antenna elements 12-15. The antenna elements 13 and 14 have a length of λ / 4 where λ is the wavelength of the radio wave. Antenna elements 13 and 14 are connected to conductors 16 and 17, respectively. The conductors 16 and 17 are connected to the transmitter 10A.

  The antenna element 12 has a length L1, the length from the one end 13A of the antenna element 13 to the other end 14A of the antenna element 14 is L2 (<L1), and the antenna element 15 has a length L3 ( <L2).

  The antenna element 12 is disposed on the opposite side of the antenna element 15 with the antenna elements 13 and 14 as the center. The distance between the antenna element 12 and the antenna elements 13 and 14 is L4, and the distance between the antenna element 15 and the antenna elements 13 and 14 is L5 (≧ L4).

  FIG. 21 is a plan view of the antenna 11A viewed from the A direction shown in FIG. The antenna elements 13 and 14 are supplied with power from the transmitter 10A through the conductors 16 and 17. Thereby, the antenna 11A transmits the radio waves RW5 to RW7 having directivity.

  The receiver 30 receives the radio wave transmitted from the antenna 11A having directivity while changing the directivity of the array antenna 20 to a plurality, and specifies the position of the transmitter 10A by the method described in the first embodiment.

  In the transmission / reception system 100A, the receivers 30A and 30B described in the second and third embodiments may be used instead of the receiver 30. The receivers 30A and 30B receive the radio waves transmitted from the antenna 11A having directivity while changing the directivity of the array antenna 20 to a plurality, and transmit the radio waves by the methods described in the second and third embodiments, respectively. The position of the machine 10A is specified.

  Thus, the receivers 30, 30 </ b> A, and 30 </ b> B can specify the position of the transmitter 10 </ b> A even when the transmitter transmits radio waves having directivity.

  In the above description, the antenna 11A is attached to the transmitter 10A and the array antenna 20 is attached to the receiver 30. However, in the present invention, the antenna 11A is not limited to this. 30 and the array antenna 20 may be attached to the transmitter 10A.

  Others are the same as Embodiments 1-3.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a transmission / reception system capable of specifying the position of a transmitter.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of the transmission / reception system by Embodiment 1 of this invention. It is a schematic block diagram of the receiver shown in FIG. It is a conceptual diagram of a received signal strength profile. It is a conceptual diagram of a position signal intensity profile. It is a related figure of the correlation coefficient computed by Formula (1), and the position of a transmitter. It is a flowchart for demonstrating the operation | movement which pinpoints the position of the transmitter in the receiver shown in FIG. 6 is a schematic block diagram of a receiver according to Embodiment 2. FIG. FIG. 10 is a conceptual diagram of a received signal strength profile in the second embodiment. It is another relationship figure of the correlation coefficient computed by Formula (1), and the position of a transmitter. It is a flowchart for demonstrating the operation | movement which pinpoints the position of the transmitter in the receiver shown in FIG. 11 is a schematic block diagram of a receiver in a third embodiment. FIG. It is a conceptual diagram of a real part received signal profile and an imaginary part received signal profile. It is a conceptual diagram of a real part position signal profile and an imaginary part position signal profile. It is a layout of an experimental environment. It is a correlation calculation result at the time of using the received signal strength profile RSSI in Embodiment 1,2. 16 is a graph of a correlation coefficient ρ on a dotted line A-A ′ in FIG. 15. It is a correlation calculation result at the time of using the complex received signal profile in Embodiment 3. 18 is a graph of correlation coefficient ρ ′ on dotted line A-A ′ in FIG. 17. FIG. 10 is a schematic diagram of a transmission / reception system according to a fourth embodiment. FIG. 20 is a vertical sectional view of the antenna shown in FIG. 19. It is a top view of the antenna seen from the A direction shown in FIG.

Explanation of symbols

  10, 10A transmitter, 11, 11A antenna, 12-15, 21-27 antenna element, 16, 17 conductor, 20 array antenna, 30, 30A, 30B receiver, 31, 31A receiver, 32, 32A correlation calculator 33, 33A, 33B Profile holder, 34, 34A, 34B Maximum value detector, 35, 35A Control voltage generation circuit, 36 Varactor diode, 41 units, 42, 43 shelves, 50, 60 rooms, 51, 52, 61 ˜64 walls, 53, 65 floors, 70 position detection target area, 100, 100A transmission / reception system.

Claims (15)

A transmitter that transmits radio waves,
A receiver for receiving radio waves from the transmitter via an antenna capable of electrically switching directivity;
The receiver compares a received signal profile indicating a plurality of received radio wave intensity profiles received by changing the directivity of the antenna a plurality of times with a reference signal profile indicating each position of the transmitter. A transmission / reception system that identifies a location.   The transmission / reception system according to claim 1, wherein the transmitter transmits the radio wave via another antenna capable of transmitting an omnidirectional radio wave.   The transmission / reception system according to claim 1, wherein the transmitter transmits the radio wave via another antenna set to a predetermined directivity. A transmitter that transmits radio waves via an antenna capable of electrically switching directivity;
A receiver for receiving radio waves from the transmitter,
The receiver receives a radio wave transmitted by changing the directivity of the antenna a plurality of times, and receives a received signal profile indicating an intensity profile of the received plurality of received radio waves as a reference signal indicating each position of the transmitter A transmission / reception system that identifies a position of the transmitter in comparison with a profile.   The transmission / reception system according to claim 4, wherein the receiver receives radio waves from the transmitter via another antenna capable of receiving omnidirectional radio waves.   The transmission / reception system according to claim 4, wherein the receiver receives radio waves from the transmitter via another antenna set to have a predetermined directivity.   The transmission / reception system according to claim 4, wherein the receiver receives a radio wave from the transmitter via another antenna capable of electrically switching directivity. The reference signal profile consists of a plurality of position signal profiles indicating each position of the transmitter,
The receiver calculates a correlation coefficient between the received signal profile and each of the plurality of position signal profiles, and specifies a position corresponding to the position signal profile having the maximum correlation coefficient as the position of the transmitter. The transmission / reception system according to any one of claims 1 to 7. The receiver
A receiver for converting the received received radio wave into the received signal profile;
A profile holder that holds the plurality of position signal profiles in association with a plurality of position information, and sequentially outputs each position signal profile and position information corresponding to the position signal profile;
A correlation calculator that calculates a correlation coefficient between a received signal profile from the receiver and a position signal profile from the profile holder, and outputs the calculated correlation coefficient;
Based on the position information from the profile holder and the correlation coefficient from the correlation calculator, the position information that maximizes the correlation coefficient is detected, and the detected position information is specified as the position of the transmitter. The transmission / reception system according to claim 8, further comprising a maximum value detector.   The transmission / reception system according to claim 8 or 9, wherein the plurality of position signal profiles are profiles measured by fixing one of the transmitter and the receiver and moving either of the other. The plurality of position signal profiles comprises a plurality of first and second position signal profiles,
The plurality of first position signal profiles are profiles measured in advance by changing the directivity of the antenna into a plurality of patterns according to a first pattern,
The plurality of second position signal profiles are profiles measured in advance by changing the directivity of the antenna into a plurality of second patterns different from the first pattern,
The receiver has a first correlation coefficient between a first received signal profile and each of the plurality of first position signal profiles when the directivity of the antenna is changed to a plurality by a first pattern. When a plurality of maximum values are detected from the first correlation coefficient, a second received signal profile is generated when the directivity is changed to a plurality by the second pattern, The transmission / reception system according to claim 8, wherein a position of the transmitter is specified by calculating a second correlation coefficient between the generated second received signal profile and each of the plurality of second position signal profiles. .   The receiver identifies, as a position of the transmitter, position information that matches position information corresponding to the maximum value of the second correlation coefficient among a plurality of position information corresponding to the plurality of maximum values. The transmission / reception system according to claim 11. Each of the received signal profile and the plurality of position signal profiles includes a real part and an imaginary part,
The receiver calculates a correlation coefficient between the received signal profile and each of the plurality of position signal profiles using the real part and the imaginary part, and corresponds to the position signal profile having the maximum correlation coefficient. The transmission / reception system according to claim 8, wherein a position to be specified is specified as a position of the transmitter. The antenna is
A plurality of antenna elements;
A control voltage generation circuit for generating a control voltage pattern for changing the directivity of the antenna;
14. The directivity changer according to claim 1, further comprising: a directivity changer that changes the directivity of the plurality of antenna elements into a plurality according to the control voltage pattern from the control voltage generation circuit. Transmission / reception system.   The transmission / reception system according to any one of claims 1 to 14, wherein the antenna is an antenna whose directivity can be switched by reactance.

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