Responder and positioning system

Abstract

To suppress the influence of multipath in a short time.SOLUTION: A responder 100 receives the interrogation wave Pt from an interrogator 200 and transmits the response wave Pr to the interrogator 200. The responder includes: a plurality of antenna elements 101 which receive the interrogation wave Pt; a reference signal generator 112 which generates a reference signal; a plurality of modulator / demodulator 111 which receive the interrogation wave Pt and output quadrature phase amplitudes based on the received signal and the reference signal output from the antenna element 101; a parallel-to-time-series signal converter 113 which converts the parallel signals of quadrature phase amplitudes output from the respective modulator / demodulator 111 into time-series signals; a frequency divider 106 which outputs a frequency-divided signal having a frequency and a phase for detecting the time-series signal; a multiplier 107 which outputs a multiplication signal obtained by multiplying the time-series signal and the frequency-divided signal; and a beam selector 103 which determines the direction of arrival of the interrogation wave Pt based on the multiplication signal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a transponder and a positioning system. [Background technology]

[0002] Conventionally, various transponders that receive a query wave from an interrogator and transmit a response wave to the interrogator have been used. In such transponders, a query wave reaches the transponder through multiple propagation paths such as a direct wave and a reflected wave, generating a phase difference according to the difference in the propagation distance. When these waves overlap, a reduction in reception strength and a phase shift occur, adversely affecting the quality of the received signal at the transponder; this is known as multipath. In order to suppress the effect of multipath, for example, Patent Document 1 proposes a method of separating a direct wave and a reflected wave from a query wave by measuring the arrival direction and arrival delay time of a signal arriving at an antenna and obtaining a PDA (Power, Delay, Angle) profile. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-91844 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the responder disclosed in Patent Document 1, in order to obtain the PDA profile, it is necessary to execute a calculation flow such as the FFT-MUSIC method using fast Fourier transform (FFT). Also, in order to extract a signal arriving from a specific direction based on the PDA profile, it is necessary to calculate a weight that gives directivity. Thus, determining the arrival direction of a signal based on the PDA profile requires a large number of product-sum calculations, which takes a considerable amount of time. In conventional responders such as those disclosed in Patent Document 1, such a large number of product-sum calculations are performed by software. [Means for solving the problem]

[0005] In order to solve the above problem, a transponder of the present invention is a transponder that receives an interrogation wave from an interrogator and transmits a reply wave to the interrogator, and is characterized in that it comprises a plurality of antenna elements that receive the interrogation wave, a reference signal generator that generates a reference signal, a plurality of modulator-demodulators that output a quadrature amplitude based on a received signal that is output from the antenna elements upon receiving the interrogation wave and the reference signal, a parallel-to-time series signal converter that converts the parallel signals of the quadrature amplitude output from each of the modulator-demodulators into a time series signal, a frequency divider that outputs a frequency-divided signal having a frequency and phase for detecting the time series signal, a multiplier that outputs a multiplied signal obtained by multiplying the time series signal by the frequency-divided signal, and a beam selector that determines the direction of arrival of the interrogation wave based on the multiplied signal. [Brief description of the drawings]

[0006] [Figure 1] FIG. 2 is a diagram illustrating an example of use of a responder according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a responder according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing the modem and reference signal generator of the transponder in FIG. 2. [Figure 4] 3 is a flowchart showing a process for determining the direction of arrival of a query wave in the transponder of FIG. 2; [Diagram 5] 3 is a flowchart showing a process of generating a response wave in the transponder of FIG. 2. [Figure 6] 3 is a flowchart showing an operation flow of an embodiment of a positioning system including the transponder of FIG. 2; [Figure 7] 3 is a diagram showing the configuration of a robot arm that is an embodiment of a positioning system including the transponder of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] First, the present invention will be briefly described. In order to solve the above problems, a first aspect of the present invention provides a transponder that receives an interrogation wave from an interrogator and transmits a reply wave to the interrogator, and is characterized in that it comprises a plurality of antenna elements that receive the interrogation wave, a reference signal generator that generates a reference signal, a plurality of modulator-demodulators that output a quadrature amplitude based on a received signal that is output from the antenna elements upon receiving the interrogation wave and the reference signal, a parallel-to-time series signal converter that converts the parallel signals of the quadrature amplitude output from each of the modulator-demodulators into a time series signal, a frequency divider that outputs a frequency-divided signal having a frequency and phase for detecting the time series signal, a multiplier that outputs a multiplied signal obtained by multiplying the time series signal by the frequency-divided signal, and a beam selector that determines the direction of arrival of the interrogation wave based on the multiplied signal.

[0008] According to this aspect, the antenna element, the reference signal generator, the modem, the parallel-to-time series signal converter, the frequency divider, the multiplier, and the beam selector are provided. These components allow the use of hardware, not software, to perform calculations for suppressing the effects of multipath using fast Fourier transform or the like. Therefore, the effects of multipath can be suppressed in a short time.

[0009] A second aspect of the responder of the present invention is an aspect dependent on the first aspect, characterized in that the divider changes the division ratio of the divided signal over time, and the beam selector determines the direction of arrival based on the intensity of the multiplied signal.

[0010] According to this aspect, the arrival direction is determined based on the intensity of the multiplied signal generated based on the frequency-divided signal whose frequency division ratio changes over time, so that the arrival direction can be determined by serial detection.

[0011] A third aspect of the responder of the present invention is an aspect dependent on the first aspect, characterized in that the frequency divider outputs a plurality of frequency-divided signals having different frequency division ratios, and the beam selector determines the direction of arrival based on the intensity of the multiplied signal.

[0012] According to this aspect, the arrival direction is determined based on the intensity of a multiplied signal generated based on a plurality of frequency-divided signals having different frequency division ratios, so that the arrival direction can be determined by detecting in parallel.

[0013] A responder according to a fourth aspect of the present invention is an aspect dependent on the first aspect, and includes: an arrival direction memory unit that stores a frequency division ratio as arrival direction information of the interrogation wave output from the beam selector; and a quadrature phase amplitude memory unit that stores the quadrature phase amplitude, wherein the frequency divider outputs a response wave frequency-divided signal having a frequency corresponding to the frequency division ratio as the arrival direction information to the multiplier, the multiplier multiplies the response wave frequency-divided signal by a response wave time series signal based on the quadrature phase amplitude stored in the quadrature phase amplitude memory unit, and outputs a response wave multiplied signal to the parallel-to-time series signal converter, the parallel-to-time series signal converter converts the response wave multiplied signal into a response wave parallel signal and outputs it to the modem, the modem generates the response wave of a response wave quadrature phase amplitude corresponding to the response wave parallel signal based on a response wave reference signal, and the multiple antenna elements transmit the response wave to the interrogator.

[0014] According to this aspect, the frequency divider outputs a frequency-divided signal for the response wave to the multiplier, the multiplier outputs a multiplied signal for the response wave to the parallel-to-time series signal converter, the parallel-to-time series signal converter converts the multiplied signal for the response wave into a parallel signal for the response wave and outputs it to the modem, the modem generates a response wave with a quadrature phase amplitude for the response wave, and the antenna element transmits the response wave to the interrogator. With this configuration, it is possible to suitably transmit the response wave to the interrogator while suppressing the effects of multipath in a short time.

[0015] The responder of a fifth aspect of the present invention is an aspect dependent on the first aspect and is characterized in that it comprises a reception time discriminator that discriminates the reception time at which the interrogation wave is received by the antenna element based on a predetermined signal component contained in the multiplied signal.

[0016] According to this aspect, a reception time discriminator is provided for discriminating the reception time at which the interrogation wave is received by the antenna element, so that the reception time of the interrogation wave can be ascertained, and for example, the timing of transmitting a reply wave to the interrogator can be optimized based on the reception time of the interrogation wave.

[0017] The responder of the sixth aspect of the present invention is an aspect dependent on the fourth aspect, and is characterized in that it comprises a reception time discriminator that discriminates the reception time at which the interrogation wave is received by the antenna element based on a predetermined signal component contained in the multiplied signal, and the beam selector determines the output time of the frequency-divided signal for the reply wave based on the reception time.

[0018] According to this aspect, a reception time discriminator is provided for discriminating the reception time when the interrogation wave is received by the antenna element, and the beam selector determines the output time of the frequency-divided signal for the reply wave based on the reception time, thereby optimizing the timing of transmitting the reply wave to the interrogator.

[0019] A seventh aspect of the present invention is a positioning system comprising a responder of any one of the first to sixth aspects, the interrogator, a distance calculation unit that calculates a distance from the interrogator to the responder, and a position measurement unit that measures a position of the responder, wherein the interrogator outputs the interrogation wave including a specific signal pattern, the distance calculation unit calculates the distance from the interrogator to the responder based on a difference between a time when the interrogation wave is transmitted from the interrogator and a time when the interrogator receives the reply wave transmitted from the responder, and a predetermined holding time, and the position measurement unit measures the position of the responder based on the distance.

[0020] According to this aspect, the interrogator outputs an interrogation wave including a specific signal pattern, the distance calculation unit calculates the distance from the interrogator to the transponder based on the difference between the time when the interrogation wave is transmitted from the interrogator and the time when the interrogator receives the reply wave transmitted from the transponder and the predetermined holding time, and the position measurement unit measures the position of the transponder based on the distance. With this configuration, the position of the transponder can be measured accurately.

[0021] An eighth aspect of the positioning system of the present invention is an aspect dependent on the seventh aspect, and is characterized in that it comprises a mechanical body having a movable part and a fixed part, the interrogator is provided in the fixed part, and the responder is provided in the movable part.

[0022] According to this aspect, the interrogator is provided on the fixed part, and the responder is provided on the movable part. With this configuration, the position of the responder provided on the movable part can be accurately measured.

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. A responder 100 of the present invention is a responder that receives a query wave Pt from an interrogator 200 and transmits a response wave Pr to the interrogator 200 (see FIG. 2). First, an example of use of the responder 100 of one embodiment of the present invention will be described with reference to FIG. 1.

[0024] 1, when the responder 100 receives a query wave Pt from the interrogator 200, it receives a direct wave that reaches the responder 100 directly from the interrogator 200, and a reflected wave that reaches the responder 100 after being reflected by an object O from the interrogator 200. In addition, in Fig. 1, the direct wave is designated as direct wave Pt1, the reflected wave that reaches the responder 100 after being reflected only by object O1 is designated as reflected wave Pt2, the reflected wave that reaches the responder 100 after being reflected only by object O2 is designated as reflected wave Pt3, and the reflected wave that reaches the responder 100 after being reflected by both objects O1 and O2 is designated as reflected wave Pt4.

[0025] Generally, the reflected wave transmitted from the interrogator 200 arrives at the transponder 100 later than the direct wave. Furthermore, the same is true when the reply wave Pr returned from the transponder 100 to the interrogator 200 is received by the interrogator 200. For this reason, radio waves propagated along different paths arrive at different times, in other words, the direct wave component and the reflected wave component are mixed, which may dull the received waveform and cause the so-called multipath effect. As a method for suppressing such a multipath effect, there is a method of separating the direct wave Pt1 and the reflected waves Pt2 to Pt4 from the interrogation wave Pt.

[0026] Therefore, the details of the responder 100 according to an embodiment of the present invention capable of separating a direct wave and a reflected wave from a query wave Pt will be described below with reference to Figs. 2 to 5. First, with reference to Fig. 2, the operation of the responder 100 when the responder 100 receives the query wave Pt will be described together with the configuration of the responder 100. Note that Fig. 2 shows both the manner in which the responder 100 receives the query wave Pt with a wavelength λ and the manner in which the responder 100 transmits a response wave Pr with a wavelength λ. In detail, the responder 100 receives the query wave Pt from a direction inclined at an angle Θ with respect to the Z direction in Fig. 2 that is perpendicular to the receiving surface of the antenna element 101, and transmits the response wave Pr from the responder 100 in the direction opposite to the receiving direction, using the responder 100 having an array antenna in which the receiving surface of the antenna element 101 is arranged in a plane in the X direction in Fig. 2 and the Y direction perpendicular to the X direction.

[0027] The interrogation wave Pt is an electric wave (electromagnetic wave) having a waveform modulated by an appropriate method with various information such as ID (IDENTIFICATION) information, which is an identification number for identifying the responder 100 that receives it, and synchronization information. The modulation method can be selected from phase modulation, amplitude modulation, orthogonal frequency division multiplexing, etc. The carrier waves used as the interrogation wave Pt and the response wave Pr can be microwaves, millimeter waves, terahertz waves, etc.

[0028] The antenna element 101 has the function of receiving the interrogation wave Pt, and a plurality of them are arranged at regular intervals in one dimension (for example, the X direction in FIG. 2) or two dimensions (for example, the X direction in FIG. 2 and the Y direction intersecting with the X direction) to form an array antenna. Note that the transponder 100 of this embodiment has an array antenna in which the antenna elements 101 are arranged two-dimensionally, but for ease of explanation, the interrogation wave Pt and the response wave Pr are considered to be inclined only in the X direction with respect to the Z direction. Here, generally, the array is mounted as an array of patch antennas on a substrate, and the electric field amplitude distribution A oscillating on the surface of the array antenna is T (x i , t) can be expressed by the following equation (1).

[0029]

number

[0030] where k T is the wave vector of the interrogation wave Pt. i is a vector that points from the origin of the coordinate axis to the position of the ith antenna. ω is the carrier angular frequency of the interrogation wave Pt. The phase difference φ is the difference between the phase of the interrogation wave Pt and the phase of the LO signal, which is a signal output by the local oscillator 112b described later, at the position of the bidirectional mixers 111b and 111c. If the phase of the interrogation wave Pt is modulated, this phase difference φ includes the modulation phase. Although polarization dependency is not particularly mentioned here, a dual-polarized antenna that can independently receive polarization components in two orthogonal directions can also be used if necessary.

[0031] 2 and 3, the modem 111 is connected to each of the antenna elements 101. As shown in Fig. 3, the modem 111 has a bidirectional amplifier 111a and bidirectional mixers 111b and 111c. The modem 111 amplifies an electric signal output from the antenna element 101 by the bidirectional amplifier 111a, and then branches the signal and inputs it to the bidirectional mixers 111b and 111c. As shown in Fig. 3, the bidirectional mixers 111b and 111c are connected to the path 104, and as shown in Fig. 2, the path 104 is connected to the parallel-to-time series signal converter 113.

[0032] 3, the reference signal generator 112 is composed of a local oscillator 112b and a ±π / 2 shifter 112a. The local oscillator 112b has a frequency ω LO The signal oscillates at and branches into two transmission lines 112c. One signal becomes an in-phase LO signal as is, and the other signal becomes an LO signal with a quadrature phase after being delayed by a phase of π / 2 by the ±π / 2 shifter 112a. The signal is then connected with equal-length wiring to prevent phase differences, and distributed to all bidirectional mixers (bidirectional mixers 111b and 111c).

[0033] With this configuration, all bidirectional mixers perform quadrature demodulation with the same phase, and the amplitude A of two orthogonal phase components is obtained as a baseband signal. I (x i ,t), A Q (x i ,t). Hereinafter, the set of both amplitudes will be called "quadrature phase amplitudes." This action is shown using the following equations (2) and (3). Note that in the following equations (2) and (3), ω LO In actual operation, terms including LO Only terms not including the above remain, and the quadrature phase amplitude information for each corresponding cell in the parallel-to-time series signal converter 113 is temporarily held in the form of an analog signal.

[0034]

number

[0035]

number

[0036] Here, the method of determining the arrival direction of the interrogation wave Pt in the transponder 100 of this embodiment will be described with reference to the flowchart of Fig. 4 as follows. First, in step S110, the parallel-to-time series signal converter 113 converts the analog signals of quadrature phase amplitude held in parallel in each cell into a time series signal. Specifically, for example, a bucket brigade method can be used, which is a method based on the principle of CCD (Charge Coupled Device) in which analog signals are held as electric charges and transferred sequentially to adjacent cells. As another example, an active matrix method used in liquid crystal displays can also be used.

[0037] Next, in step S120, the quadrature phase amplitude information is converted into digital data by an A / D converter (not shown) and is sequentially stored in the quadrature phase amplitude storage unit 102. Note that this step S120 can be performed in parallel with step S110.

[0038] Next, in step S130, the multiplier 107 shown in FIG. 2 multiplies one or more AC signals output by the second divider of the divider 106 shown in FIG. 2, which has a first divider and a second divider with different frequencies, by the time series signal converted by the parallel-to-time series signal converter 113. As the multiplier 107, for example, an analog multiplier made of transistors can be used. As shown in FIG. 2, the first divider indicated by reference number 1 is connected to the parallel-to-time series signal converter 113, the quadrature phase amplitude storage unit 102, and the reception time discriminator 108, and the second divider indicated by reference number 2 is connected to the multiplier 107 connected to the parallel-to-time series signal converter 113 and the beam selector 103.

[0039] Next, in step S140, the beam selector 103 shown in FIG. 2 scans the division ratio of the second frequency divider to identify the division ratio corresponding to the strongest output of the multiplier 107 from one or more multiplied signals, and stores this information in the arrival direction storage unit 105 shown in FIG. 2. Since the direct wave component generally has a higher intensity than the reflected wave, the process of step S140 ultimately means identifying the arrival direction of the direct wave. The scanning of the division ratio of the second frequency divider may be performed by scanning the division ratio over time, or the one-dimensional antenna arrays arranged in the X direction may be arranged in multiple directions in the Y direction perpendicular to the X direction, and the direct wave components may be obtained simultaneously and in parallel by multiplying each of the one-dimensional antenna arrays by different frequencies.

[0040] A series of operations from step S110 to step S140, which are executed by the parallel-to-time series signal converter 113, the multiplier 107, the beam selector 103, etc., is equivalent to obtaining the spatial frequency of the quadrature amplitude distributed in the X direction, that is, the Fourier coefficients. That is, by executing steps S110 to S140, it is possible to quickly and regularly obtain the direction of arrival of the direct wave corresponding to the division ratio of the output with the highest intensity.

[0041] 2 monitors the pattern of data in the quadrature phase amplitude storage unit 102. When the identification number of the target transponder 100 is added to the interrogation wave Pt by, for example, phase modulation and transmitted, the transponder 100 generates a trigger signal for switching from reception of the interrogation wave Pt to transmission of the reply wave Pr at that time when the identification number of the transmitted interrogation wave Pt matches the identification number of its own station. When the transponder 100 is used for positioning the transponder 100 or for measuring the distance from the interrogator 200 to the transponder 100, if a holding time Th from the completion time of reception of the interrogation wave Pt to the start time of transmission of the reply wave Pr is specified, a waiting time may be set to satisfy this and the generation of the trigger signal may be adjusted.

[0042] Next, the process of generating the response wave Pr in the responder 100 of this embodiment will be described with reference to the flowchart in Fig. 5. First, when the reference signal generator 112 detects a trigger signal in step S210, the beam selector 103 sets the division ratio of the second frequency divider of the frequency divider 106 based on the information stored in the arrival direction storage unit 105 in step S220.

[0043] Next, in step S230, quadrature phase amplitude storage unit 102 prepares an analog signal of time-series information by, for example, converting the stored digital information of quadrature phase amplitude into an analog signal using a D / A converter (not shown), and outputs the analog signal to multiplier 107. Then, in step S240, multiplier 107 multiplies the output of the second frequency divider of frequency divider 106 by the output of quadrature phase amplitude storage unit 102, and transmits the multiplied result to parallel-to-time-series signal converter 113.

[0044] Next, in step S250, the parallel-to-time series signal converter 113 converts the time series signal into a parallel signal by a CCD or active matrix method, similar to when the interrogation wave Pt was received, and outputs the parallel signal to the modem 111. Then, in step S260, the reference signal generator 112 inverts the sign of the ±π / 2 shifter 112a to generate a conjugate LO signal, which is a time-reversed LO signal. When expressed on an IQ plane, which is a plane defined by the in-phase axis and the quadrature axis, this becomes a wave that rotates in the opposite direction compared to when it was received.

[0045] Then, in step S270, the output from the D / A converter (not shown) is mixed with the conjugate LO signal by the modem 111, and the mixed signal is output to the antenna element 101 via the bidirectional amplifier 111a, and the response wave Pr is returned to the interrogator 200. Here, the electric field amplitude distribution A R (x i ,t) is the quadrature phase amplitude A I (x i ,t), A Q (x i , t), it can be expressed by the following equation (4).

[0046]

number

[0047] Here, the sign inversion in the ±π / 2 shifter 112a causes the quadrature component sin(ω LO As a result of this series of processing, the wave vector k of the output response wave Pr is R is the wave vector k at the time of receiving the interrogation wave Pt T It propagates in the opposite direction to

[0048] Strictly speaking, when comparing equation (1) and equation (4), a phase difference of 2φ occurs, and the holding time from the time when the interrogation wave Pt is received to the time when the reply wave Pr starts to be transmitted (holding time t h) generates an error. If there is a need to correct this, a method of correcting it by adjusting the quadrature phase amplitude data stored in the storage unit 102 can be considered. In addition, the correction may be performed by providing a phase shifter immediately after the output of the local oscillator 112b.

[0049] As described above, the transponder 100 of this embodiment, which receives the interrogation wave Pt from the interrogator 200 and transmits the reply wave Pr to the interrogator 200, includes a plurality of antenna elements 101 that receive the interrogation wave Pt. The transponder 100 of this embodiment also includes a reference signal generator 112 that generates a reference signal, a plurality of modulator-demodulators 111 that output a quadrature amplitude based on a received signal and a reference signal that are output from the antenna elements 101 upon receiving the interrogation wave Pt, and a parallel-to-time series signal converter 113 that converts the parallel signals of the quadrature amplitude output from each of the modulator-demodulators 111 into a time series signal. The transponder 100 of this embodiment also includes a frequency divider 106 that outputs a frequency-divided signal having a frequency and phase for detecting the time series signal, a multiplier 107 that outputs a multiplied signal obtained by multiplying the time series signal by the frequency-divided signal, and a beam selector 103 that determines the direction of arrival of the interrogation wave Pt based on the multiplied signal.

[0050] As described above, the responder 100 of this embodiment includes the antenna element 101, the reference signal generator 112, the modem 111, the parallel-to-time series signal converter 113, the frequency divider 106, the multiplier 107, and the beam selector 103. These components allow the responder 100 to perform calculations for suppressing the effects of multipath using fast Fourier transform or the like, using hardware instead of software. Therefore, the responder 100 of this embodiment can suppress the effects of multipath in a short time. The reference signal is an AC signal having the frequency and phase of a carrier wave.

[0051] 4, the frequency divider 106 can change the division ratio of the frequency-divided signal over time, and the beam selector 103 can determine the arrival direction of the interrogation wave Pt based on the intensity of the multiplied signal. That is, the transponder 100 of this embodiment can determine the arrival direction of the interrogation wave Pt by serially detecting the multiplied signal whose division ratio has been changed over time.

[0052] On the other hand, in the transponder 100 of this embodiment, in steps S130 and S140 of Fig. 4, the frequency divider 106 outputs multiple frequency-divided signals having different frequency division ratios in parallel, and the beam selector 103 can determine the arrival direction of the interrogation wave Pt based on the intensity of the multiplied signal. That is, the transponder 100 of this embodiment can detect multiple multiplied signals in parallel to determine the arrival direction of the interrogation wave Pt.

[0053] As described above, the responder 100 of this embodiment includes the arrival direction storage unit 105 and the quadrature phase amplitude storage unit 102. The arrival direction storage unit 105 stores a frequency division ratio as arrival direction information of the interrogation wave Pt output from the beam selector 103, and the quadrature phase amplitude storage unit 102 stores a quadrature phase amplitude. Here, in step S220 of Fig. 5, the frequency divider 106 outputs to the multiplier 107 a frequency-divided signal for the response wave (frequency division ratio set by the second frequency divider) having a frequency corresponding to the frequency division ratio as arrival direction information of the interrogation wave Pt. 5, the multiplier 107 multiplies the response wave frequency-divided signal (frequency division ratio set by the second frequency divider) by the response wave time-series signal (output of the quadrature phase amplitude storage unit 102) based on the quadrature phase amplitude stored in the quadrature phase amplitude amplitude storage unit 102, and outputs the response wave multiplied signal to the parallel-to-time series signal converter 113. Also, in step S250 in FIG. 5, the parallel-to-time series signal converter 113 converts the response wave multiplied signal into a response wave parallel signal (time series signal converted into a parallel signal) and outputs it to the modem 111. Also, in steps S260 and S270 in FIG. 5, the modem 111 generates a response wave Pr of a quadrature phase amplitude for the response wave corresponding to the response wave parallel signal (time series signal converted into a parallel signal) based on the response wave reference signal (conjugate LO signal), and the multiple antenna elements 101 transmit the response wave Pr to the interrogator 200. The responder 100 of this embodiment has such a configuration and is therefore capable of suitably transmitting the response wave Pr to the interrogator 200 while suppressing the effects of multipath in a short period of time.

[0054] In this embodiment, the frequency-divided signal, time-series signal, multiplied signal, parallel signal, reference signal, and quadrature amplitude for the response wave Pr are the same as or simply inverted from the frequency-divided signal, time-series signal, multiplied signal, parallel signal, reference signal, and quadrature amplitude for the query wave Pt. However, the frequency-divided signal, time-series signal, multiplied signal, parallel signal, reference signal, and quadrature amplitude for the response wave Pr may be reconstructed by applying corrections to those for the query wave Pt.

[0055] As described above, the transponder 100 of this embodiment includes a reception time discriminator 108 that discriminates the reception time at which the interrogation wave Pt is received by the antenna element 101, based on a predetermined signal component contained in the multiplied signal. The beam selector 103 can then determine the output time of the frequency-divided signal for the reply wave, based on the reception time. This allows the transponder 100 of this embodiment to grasp the reception time of the interrogation wave Pt, and the transponder 100 of this embodiment can optimize the timing of transmitting the reply wave Pr to the interrogator 200, based on the reception time of the interrogation wave Pt.

[0056] Next, an embodiment of a positioning system 1 using the transponder 100 of this embodiment will be described with reference to Fig. 6. In the positioning system 1 of this embodiment, the interrogator 200 modulates a signal including the identification number of the target transponder 100 in a predetermined manner, generates an interrogation wave Pt, and transmits it to the transponder 100.

[0057] Like the transponder 100 of this embodiment, the interrogator 200 of the positioning system 1 of this embodiment also generates directional waves using an array antenna in which multiple antenna elements 101 are arranged at predetermined intervals along the receiving surface of the transponder 100. When the position of the desired transponder 100 is unknown, it is preferable that the interrogator 200 scans the direction of the directional wave from the interrogator 200 and retains information on that direction at the time when the reply wave Pr is returned.

[0058] When the transponder 100 detects its own identification number, it writes necessary information in the form of quadrature amplitude in advance in the quadrature amplitude storage unit 102, and transmits the reply wave Pr by reading out this information. It operates so that there is a hold time Th from the time when reception of the interrogation wave Pt is completed to the time when transmission of the reply wave Pr starts. However, a delay function may be added as necessary.

[0059] In the positioning system 1 of this embodiment, the interrogator 200 is provided with a distance calculation unit 201 that calculates the distance from the interrogator 200 to the transponder 100, and a position measurement unit 202 that measures the position of the transponder 100. There is no particular limitation on the locations where the distance calculation unit 201 and the position measurement unit 202 are provided, and they may be provided in the transponder 100, or may be provided in a location separate from the interrogator 200 and the transponder 100. When the interrogator 200 determines that reception of the reply wave Pr is complete, it calculates the time between the transmission completion time of the interrogation wave Pt and the reception start time of the reply wave Pr, and the holding time t h from propagation time t p and calculates the distance from the interrogator 200 to the transponder 100. The position of the transponder 100 is calculated from the transmission direction of the interrogation wave Pt and the distance from the interrogator 200 to the transponder 100. Note that when both the interrogator 200 and the transponder 100 are stationary, the propagation time t p and the propagation time t of the response wave Pr p is equal to

[0060] As described above, the positioning system 1 of this embodiment includes the transponder 100, the interrogator 200, a distance calculation unit 201 that calculates the distance from the interrogator 200 to the transponder 100, and a position measurement unit 202 that measures the position of the transponder 100. Here, the interrogator 200 outputs a query wave Pt that includes a specific signal pattern such as an identification number. The distance calculation unit 201 calculates the difference between the time when the interrogator 200 transmits the query wave Pt and the time when the interrogator 200 receives the reply wave Pr transmitted from the transponder 100, as well as a predetermined hold time t h , the distance from the interrogator 200 to the responder 100 is calculated based on the distance. The position measurement unit 202 then measures the position of the responder 100 based on the distance.

[0061] The positioning system 1 of the present embodiment, being configured as described above, can accurately measure the position of the responder 100. When there are multiple interrogators 200, the position of the responder 100 can be measured by the multiple interrogators 200 even if the interrogators 200 do not have directionality, and when there is only one interrogator 200, the position of the responder 100 can be measured as long as the interrogator 200 has directionality. Furthermore, when there is only one interrogator 200, the position of the responder 100 can be measured even if the interrogator 200 does not have directionality, as long as the moving direction of the responder 100 is only one direction.

[0062] Next, an embodiment of a positioning system 1 different from the positioning system 1 shown in FIG. 6, which uses a responder 100 of this embodiment, will be described with reference to FIG. 7. In this embodiment, an articulated robot 10 is installed in the center of the positioning system 1, and a responder 100 is attached to an arm tip 10a. A control device (not shown) is built into the articulated robot 10, and calculates the position of the responder 100 in a multipoint positioning manner from the distance to the responder 100 measured by communicating with eight interrogators 200 (interrogator 200a, interrogator 200b, interrogator 200c, interrogator 200d, interrogator 200e, interrogator 200f, interrogator 200g, interrogator 200h). In this embodiment, each interrogator 200 and the control device are electrically connected by wired communication, but may be connected by wireless communication.

[0063] Interrogators 200a, 200b, 200c, 200d, 200e, 200f, 200g, and 200h are arranged around the articulated robot 10, have a function of returning a response wave Pr equivalent to that of the transponder 100, and are also capable of measuring the distance between the interrogators 200. By collecting distance information between the interrogators 200 in advance in the control device, an absolute coordinate system within the positioning system 1 can be set, and the position coordinates of all the interrogators 200 can be calculated.

[0064] Since the interrogators 200 can also measure the distance from the responder 100, the position of the responder 100 can also be calculated in the absolute coordinate system. Here, eight interrogators 200 are provided, but if the three-dimensional position of the responder 100 is to be measured, it is sufficient to find unknown variables in three mutually perpendicular axis directions. For this reason, if the interrogators 200 are not all on the same plane, the position of the responder 100 can be calculated with at least four interrogators 200. Furthermore, if all the interrogators 200 are provided outside the movement range of the responder 100, the position of the responder 100 can be calculated with three interrogators 200.

[0065] In the positioning system 1 of this embodiment, an appropriate interrogator 200 can be selected depending on the wireless communication situation. Furthermore, by attaching the transponder 100 to joints other than the arm tip 10a, the positions and movements of the joints and arms of the articulated robot 10 can be measured. Furthermore, in a usage scene targeting a workpiece, the transponder 100 can be attached to a tray on which the workpiece is placed, so that the position of the workpiece can be measured. Furthermore, by operating each motor in the articulated robot 10 and the tray transport mechanism based on information regarding these positions, and at the same time having the transponder 100 track the transmission direction of the interrogation wave Pt, it becomes possible to control a plurality of mechanisms in a coordinated manner.

[0066] The positioning in the absolute coordinate system described above is also effective for setting the initial position, i.e., teaching, which is necessary before the operation of the articulated robot 10. In the conventional articulated robot 10, an encoder is provided at each joint to detect the rotation direction of the joint and the arm, and the final coordinate of the arm tip 10a is estimated. However, as the number of joints increases, the measurement error of the encoder accumulates, and furthermore, the arm and the joints are deflected due to their own weight, which may cause a large deviation from the actual position of the arm tip 10a. In order to improve this, it was necessary to increase the rigidity of the arm itself and the holding force of the reducer. On the other hand, by using the positioning system 1 of this embodiment, even if the initial state of each encoder, etc. is unknown, it is possible to grasp the state of the articulated robot 10 by, for example, attaching the transponder 100 to each part of the articulated robot 10 and measuring the position of the transponder 100 by transmitting the interrogation wave Pt from the interrogator 200.

[0067] Explaining the positioning system 1 of the present embodiment in another way, as shown in FIG. 7, the positioning system 1 of the present embodiment includes a mechanical body 12 having a multi-joint robot 10 as a movable part having an arm, joints, etc., and a fixed part 11 on which the multi-joint robot 10 is installed. The interrogator 200 is provided on the fixed part 11, and the responder 100 is provided on an arm tip part 10a of the multi-joint robot 10 as a movable part. The positioning system 1 of the present embodiment is configured in this way, and is therefore capable of accurately measuring the position of the responder 100 provided on the movable part. However, the present embodiment is not limited to this configuration, and depending on the device configuration of the mechanical body 12, for example, the responder 100 may be provided on the fixed part 11, and the interrogator 200 may be provided on the movable part.

[0068] The present invention is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present invention. The technical features in the embodiment corresponding to the technical features in each aspect described in the Summary of the Invention can be replaced or combined as appropriate to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. In addition, if the technical feature is not described as essential in this specification, it can be deleted as appropriate. For example, instead of an array antenna having multiple antenna elements, a configuration having one directional antenna element such as a parabolic antenna may be used. The present invention can be applied to the control and automatic driving of automatic guided vehicles in factories. [Explanation of symbols]

[0069] 1...positioning system, 10...articulated robot (movable part), 10a...arm tip, 11...fixed part, 12...mechanical body, 100...responder, 101...antenna element, 102..., 103...beam selector, 104...path, 105...arrival direction memory unit, 106...frequency divider, 107...multiplier, 108...reception time discriminator, 111...modulator / demodulator, 111a...bidirectional amplifier, 111b...bidirectional Directional mixer, 111c...bidirectional mixer, 112...reference signal generator, 112a...±π / 2 shifter, 112b...local oscillator, 112c...transmission line, 113...parallel-to-time series signal converter, 200...interrogator, 200a...interrogator, 200b...interrogator, 200c...interrogator, 200d...interrogator, 200e...interrogator, 200f...interrogator, 200g...interrogator, 200h...interrogator

Claims

1. A responder that receives an interrogation wave from an interrogator and transmits a response wave to the interrogator, a plurality of antenna elements for receiving the interrogation wave; a reference signal generator for generating a reference signal; a plurality of modulators and demodulators each outputting a quadrature phase amplitude based on a received signal output from the antenna element in response to receiving the interrogation wave and the reference signal; a parallel-to-time series signal converter that converts the parallel signals of quadrature phase amplitude output from each of the modulators and demodulators into a time series signal; a frequency divider that outputs a frequency-divided signal having a frequency and a phase for detecting the time series signal; a multiplier that outputs a multiplied signal obtained by multiplying the time-series signal by the frequency-divided signal; a beam selector for determining the direction of arrival of the interrogation wave based on the multiplied signal; A responder comprising:

2. 2. The responder according to claim 1, The frequency divider changes a frequency division ratio of the frequency-divided signal over time; A transponder, characterized in that the beam selector determines the direction of arrival based on the strength of the multiplied signal.

3. 2. The responder according to claim 1, the frequency divider outputs a plurality of the frequency-divided signals having different frequency division ratios; A transponder, characterized in that the beam selector determines the direction of arrival based on the strength of the multiplied signal.

4. 2. The responder according to claim 1, a direction of arrival storage unit that stores a frequency division ratio as information on the direction of arrival of the interrogation wave output from the beam selector, and a quadrature phase amplitude storage unit that stores the quadrature phase amplitude, The frequency divider outputs a response wave frequency-divided signal having a frequency corresponding to a frequency division ratio as the arrival direction information to the multiplier, the multiplier multiplies the response wave frequency-divided signal by a response wave time series signal based on the quadrature phase amplitude stored in the quadrature phase amplitude storage unit, and outputs the response wave multiplied signal to the parallel-to-time series signal converter; the parallel-to-time series signal converter converts the response wave multiplied signal into a response wave parallel signal and outputs the parallel signal to the modem; The modem generates the response wave having a quadrature phase amplitude for the response wave corresponding to the parallel signal for the response wave based on a reference signal for the response wave, A responder, characterized in that the plurality of antenna elements transmit the response wave to the interrogator.

5. 2. The responder according to claim 1, a reception time discriminator for discriminating a reception time at which the interrogation wave was received by the antenna element based on a predetermined signal component contained in the multiplied signal.

6. 5. The responder according to claim 4, a reception time discriminator for discriminating a reception time at which the interrogation wave is received by the antenna element based on a predetermined signal component included in the multiplied signal, The responder is characterized in that the beam selector determines an output time of the frequency-divided signal for the reply wave based on the reception time.

7. A responder according to any one of claims 1 to 6, The interrogator; a distance calculation unit that calculates a distance from the interrogator to the responder; a position measurement unit that measures the position of the transponder; Equipped with the interrogator outputs the interrogation wave having a predetermined signal pattern and having directionality; the distance calculation unit calculates a distance from the interrogator to the transponder based on a difference between a time when the interrogator transmits the interrogation wave and a time when the interrogator receives the response wave transmitted from the transponder, and a predetermined holding time; A positioning system, wherein the position measurement unit measures the position of the transponder based on the distance.

8. 8. The positioning system according to claim 7, A mechanical body having a movable part and a fixed part, the interrogator is provided on the fixed part, A positioning system, wherein the responder is provided on the movable part.

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