JP6894204B2 - Positioning system - Google Patents

Description

The present invention relates to a mobile station, about the positioning system that calculates the position of the own station based on the radio signals received from a plurality of fixed stations.

Currently, a positioning system (see, for example, Patent Document 1) that calculates the position of a mobile station based on the propagation distance of each of a plurality of radio signals transmitted from a plurality of fixed stations whose positions are fixed in advance to the mobile station. It is widespread.

In the positioning system described in Patent Document 1, spectrum diffusion communication is performed between a fixed station (base station) and a mobile station (mobile terminal). Specifically, the fixed station spreads the spectrum of the baseband signal by multiplying the baseband signal by a code signal based on a predetermined code. As a result, the baseband signal is encoded and the encoded signal is generated.

The code is a list of numbers represented by "0" or "1", and the number of these numbers is the code length. The baseband signal and the code signal are binary signals represented by "+1" and "-1", respectively. In the coded signal, for example, "+1" corresponds to the sign "0" and "-1" corresponds to the sign "1". In the code signal, the waveform corresponding to the predetermined code is periodically repeated.

The period of 1 bit of the baseband signal corresponds to one cycle of the code signal. Therefore, the minimum pulse width (hereinafter referred to as chip period) in the coded signal is a value calculated by dividing the period of 1 bit of the baseband signal by the code length. Since the spectral width is inversely proportional to the minimum pulse width, the spectral width of the coded signal is approximately the same as the product of the spectral width of the baseband signal and the code length. The reciprocal of the chip period is expressed as the product of the bit rate of the baseband signal and the code length, and is called the chip rate.

In the fixed station, the signal generated by superimposing the coded signal on the carrier wave is transmitted to the mobile station as a radio signal. The mobile station extracts a coded signal from the radio signal. Then, the coded signal is decoded into a baseband signal by multiplying the extracted coded signal by the coded signal described above.

When a radio signal is transmitted from a fixed station to a mobile station, the mobile station receives a radio signal that reaches its own station directly from the fixed station and a radio signal that is reflected by an object and reaches its own station. The mobile station can individually decode a plurality of encoded signals extracted from the plurality of received radio signals. The mobile station regards the propagation distance of the radio signal that was first successfully decoded as the distance between the fixed station and the mobile station, and uses this propagation distance for the calculation of the position.

Japanese Unexamined Patent Publication No. 7-181242

However, in the conventional positioning system as described in Patent Document 1, it is not possible to individually decode the coded signals extracted from the plurality of radio signals received during the elapse of the chip period. Therefore, an error occurs between the propagation distance used for the calculation of the position and the distance between the fixed station and the mobile station, and the maximum value of this error is expressed by the product of the velocity of the electromagnetic wave and the chip period. In order to reduce the error, it is necessary to increase the code length and increase the chip rate. As a result, the chip period is shortened, so that the maximum value of the error is reduced.

Naturally, the carrier frequency of the radio signal needs to be higher than the chip rate. Then, in order to realize a positioning system having a high chip rate, it is necessary to use a radio signal having a high carrier frequency.

However, in the conventional positioning system as described in Patent Document 1, the carrier frequency of the radio signal is as low as about 1 GHz. Therefore, the chip rate is as low as about 1 MHz. As a result, the conventional positioning system has a problem that the position of the mobile station cannot be calculated accurately.

The present invention has been made in view of such circumstances, and its object is to provide a positioning system that can accurately calculates the position.

The positioning system according to the present invention includes a plurality of fixed stations fixed at predetermined positions, a mobile station, and a transfer device on which the mobile station is mounted and transports a work, and the plurality of fixed stations. Each has a transmitter that transmits a radio signal whose carrier is a millimeter wave, and the mobile station is a receiver that receives a radio signal transmitted by the transmitter of the plurality of fixed stations, and the receiver is With respect to the received radio signal, the distance calculation unit that calculates the propagation distance from the source to the receiver and the distance calculation unit calculate the transmission distance based on the propagation distances of a plurality of radio signals having different transmission sources. It has a position calculation unit that calculates the position of the station, and the transfer device changes the traveling direction, stops the movement, or moves the speed based on the position information indicating the position calculated by the position calculation unit of the mobile station. There line changes, the plurality of fixed stations respective said transmitter has a directional, continuously transmits the radio signal, transmission direction of the radio signals transmitted in succession different from one another At least one of the transmitters of the plurality of fixed stations has an output antenna that outputs the radio signal, a reflector that reflects the radio signal output by the output antenna, and a reflection of the radio signal in the reflector. It is characterized by having a changing portion for changing the angle.

In the present invention, a plurality of fixed stations are fixed at predetermined positions. Each transmitter of the plurality of fixed stations transmits a radio signal having a millimeter wave carrier to the mobile station. The mobile station calculates the propagation distance from the source to the mobile station for the received radio signal. The mobile station calculates the position of its own station based on the propagation distance of a plurality of radio signals from different sources.

For example, when spectral diffusion communication is performed between a transmitter of each of a plurality of fixed stations and a mobile station, the carrier of the radio signal is a millimeter wave, so that the transmitter of each of the plurality of fixed stations has a high chip rate. It is possible to transmit a radio signal to a mobile station. When the chip rate is high, the mobile station can accurately calculate the position of its own station.
The mobile station is mounted on a transport device that transports the work. The transport device changes the traveling direction, stops the movement, or changes the moving speed based on the position information indicating the position calculated by the mobile station.

In addition , the transmitters of the plurality of fixed stations continuously transmit radio signals. The transmitter of each of the plurality of fixed stations has directivity and changes the transmission direction of the radio signal over time. Therefore, the probability that the radio signal reaches the mobile station directly from the transmitter is high, and the probability that the radio signal is reflected by an object and reaches the mobile station is low.

Further , at least one of the transmitters of the plurality of fixed stations transmits the radio signal by reflecting the radio signal output by the output antenna with a reflector. Change the reflection angle of the radio signal on the reflector. This makes it possible to continuously transmit radio signals having different transmission directions.

The positioning system according to the present invention is characterized in that the receiver has a dipole antenna or a microstrip antenna.

In the present invention, the mobile station receiver receives a radio signal using a dipole antenna or a microstrip antenna. Therefore, since the directivity of the receiver is wide, there is a high probability that the radio signal transmitted by the transmitter will be received.

In the positioning system according to the present invention, the transmitters of the two or more fixed stations do not transmit the radio signal at the same time zone, and the transmitter that transmits the radio signal is changed over time. It is characterized by that.

In the present invention, a plurality of fixed stations do not transmit radio signals in the same time zone, and the fixed stations that transmit radio signals are changed over time. Therefore, a plurality of radio signals do not interfere with each other, and information contained in the radio signals, for example, information indicating a fixed station as a transmission source, is appropriately acquired in the mobile station.

In the positioning system according to the present invention, each of the plurality of fixed stations has a coding unit that encodes the baseband signal by spreading the spectrum of the baseband signal based on a predetermined code, and the coding. The mobile station further includes a generation unit that generates the radio signal by superimposing the coded signal encoded by the unit on the carrier wave, and the mobile station generates the coded signal from the radio signal received by the receiver. It is characterized by having an extraction unit for extraction and a decoding unit for decoding the coded signal into the baseband signal by back-spreading the spectrum of the coded signal extracted by the extraction unit.

In the present invention, each of the plurality of fixed stations encodes the baseband signal by spreading the spectrum of the baseband signal based on a predetermined code, and superimposes the encoded coded signal on the carrier wave. By generating a radio signal. The mobile station extracts the coded signal from the radio signal received by the receiver and reverse-diffuses the spectrum of the extracted coded signal to decode the coded signal into a baseband signal. As described above, spectrum diffusion communication is performed between each of the plurality of fixed stations and the mobile station.

According to the present invention, the position can be calculated accurately.

It is a block diagram which shows the main part structure of the positioning system in Embodiment 1. FIG. It is a block diagram which shows the main part composition of a fixed station. It is explanatory drawing of the method of generating a radio signal. It is a block diagram which shows the main part composition of a mobile station. It is explanatory drawing of decoding of the baseband signal. It is a flowchart which shows the procedure of the process which a calculation part executes. It is a chart which shows the correlation value and propagation distance associated with the source. It is a block diagram which shows the composition of the main part of the fixed station in Embodiment 2. FIG. It is explanatory drawing of the method of changing the reflection angle of a radio signal. It is a block diagram which shows the main part structure of the positioning system in Embodiment 3. FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a main part of the positioning system 1 according to the first embodiment. The positioning system 1 is provided in the room R and includes three fixed stations 10a, 10b, 10c, a control device 11, a mobile station 12, and a transfer device 13. The fixed stations 10a, 10b, and 10c are each fixed at a predetermined position of the room R. The positions of the fixed stations 10a, 10b, and 10c are the corners of the room R and are different from each other. The fixed stations 10a, 10b, and 10c are connected to the control device 11 by wire.

The mobile station 12 is mounted on the transport device 13. The transport device 13 transports a workpiece such as a welded part, an electronic part, a substrate, or a wafer, for example. The transport device 13 is, for example, an automatic guided vehicle that moves on a predetermined route, or a mobile body such as a mobile shuttle that moves on a track installed on the ceiling or floor. The operation of the transport device 13 is managed by a production control system called a MES (Manufacturing Execute System). In the room R, walls W1, W2, and W3 that reflect radio signals exist. The transport device 13 moves in the room R while avoiding contact with the wall bodies W1, W2, and W3. The mobile station 12 moves in the room R together with the transfer device 13.

The fixed stations 10a, 10b, and 10c each transmit a radio signal to the mobile station 12 according to the instruction of the control device 11. The mobile station 12 calculates the position of its own station based on the radio signals received from the fixed stations 10a, 10b, and 10c, and outputs a position signal including position information indicating the calculated position to the carrier device 13. The transport device 13 changes the traveling direction, stops the movement, changes the moving speed, and the like based on the position information included in the position signal input from the mobile station 12.

FIG. 2 is a block diagram showing a main configuration of the fixed station 10a. The fixed station 10a includes a signal output unit 20, a clock unit 21, a coding unit 22, a code signal generator 23, a superimposition unit 24, a carrier wave generator 25, an amplifier 26, and a transmitter 27.

The signal output unit 20 acquires time information indicating the current time from the clock unit 21. When the signal output unit 20 acquires the time information from the clock unit 21, the time indicated by the time information acquired by the signal output unit 20 coincides with or substantially coincides with the time at the time of acquisition. Further, a radio signal transmission instruction is input from the control device 11 to the signal output unit 20. The signal output unit 20 acquires time information from the clock unit 21 when a transmission instruction is input. The signal output unit 20 outputs a baseband signal including time information acquired from the clock unit 21, source information indicating the fixed station 10a, coordinate information indicating the position of the fixed station 10a in coordinates, and the like to the coding unit 22. To do. A stop instruction for instructing the stop of transmission of the wireless signal is input to the signal output unit 20. The signal output unit 20 stops the output of the baseband signal when the stop instruction is input.
The time information included in the baseband signal is transmission time information indicating the transmission time. In the following, the time information included in the baseband signal will be referred to as transmission time information.

The code signal generator 23 outputs a transmission side code signal corresponding to a predetermined code to the coding unit 22. The code is a list of numbers represented by "0" or "1", and the number of these numbers is the code length. For example, when the code is "010101", the code length is 7. In the transmitting side code signal, the waveform corresponding to the predetermined code is periodically repeated.

The coding unit 22 encodes the baseband signal by spreading the spectrum of the baseband signal input from the signal output unit 20 by using the transmitting side coded signal input from the coded signal generator 23. .. The coding unit 22 outputs the coded coded signal to the superimposing unit 24.

The carrier wave generator 25 outputs the carrier wave to the superimposing unit 24. The carrier wave output by the carrier wave generator 25 is a millimeter wave. The frequency range of millimeter waves is 30 GHz to 300 GHz.
The superimposition unit 24 generates a superimposition signal by superimposing the coded signal input from the coding unit 22 on the carrier wave input from the carrier wave generator 25. The superimposition unit 24 outputs the generated superimposition signal to the amplifier 26.

The amplifier 26 amplifies the amplitude of the superposed signal input from the superimposing unit 24, and outputs the superposed signal with the amplified amplitude to the transmitter 27. The transmitter 27 transmits the superimposed signal input from the amplifier 26 to the mobile station 12 as a radio signal. Therefore, the superimposition unit 24 functions as a generation unit that generates a radio signal transmitted by the transmitter 27.

The transmitter 27 has directivity, and as shown in FIG. 1, transmits the radio signal A1 in the first direction, transmits the radio signal A2 in the second direction, and transmits the radio signal A3 in the third direction. .. The transmitter 27 switches the transmission direction of the radio signal between the first direction, the second direction, and the third direction each time a predetermined time elapses. The transmitting direction of the transmitter 27 is switched in the order of the first direction, the second direction, and the third direction.

The transmitter 27 has a changeover switch 30, three output antennas 31, 32, 33, and a changeover unit 34. The changeover switch 30 has a rod-shaped conductor 30f.
One end of the conductor 30f of the changeover switch 30 is connected to the output end of the amplifier 26 to which the superimposed signal is output. The other end of the conductor 30f is connected to one of the three output antennas 31, 32, 33.

Signals are input to each of the three output antennas 31, 32, and 33 by wire. Each of the three output antennas 31, 32, and 33 has directivity and wirelessly outputs a signal input by wire. The output directions of the three output antennas 31, 32, and 33, which output signals wirelessly, are different from each other. A superimposed signal is input from the amplifier 26 to the output antenna to which the other end of the conductor 30f of the changeover switch 30 is connected among the three output antennas 31, 32, 33, and the superimposed signal is output as a wireless signal from this output antenna. Will be done.

When the output antenna 31 outputs a radio signal, the radio signal A1 is transmitted in the first direction. When the output antenna 32 outputs a radio signal, the radio signal A2 is transmitted in the second direction. When the output antenna 33 outputs a radio signal, the radio signal A3 is transmitted in the third direction.

The switching unit 34 switches the connection destination of the other end of the conductor 30f of the switching switch 30 to one of the three output antennas 31, 32, 33 each time a predetermined period elapses. As a result, each time a predetermined period elapses, the output destination for outputting the superimposed signal, that is, the wireless signal is switched to one of the three output antennas 31, 32, 33. The switching unit 34 switches the connection destination of the other end of the conductor 30f in the order of the output antennas 31, 32, 33. As a result, the transmission direction in which the transmitter 27 transmits the radio signal is switched in the order of the first direction, the second direction, and the third direction, and the radio signals having different transmission directions are continuously transmitted.

The timing at which the switching unit 34 changes the connection destination of the other end of the conductor 30f of the changeover switch 30 may be adjusted based on the time indicated by the clock unit 21 or may be adjusted based on a timer (not shown). Alternatively, the adjustment may be made based on the instruction of the control device 11.

When a transmission instruction is input from the control device 11, the signal output unit 20 continuously outputs a baseband signal to the coding unit 22. At this time, the signal output unit 20 outputs the baseband signal to the coding unit 22 each time a predetermined time elapses. Therefore, the transmitter 27 continuously transmits the radio signals, and the transmission directions of the three radio signals continuously transmitted by the transmitter 27 are different from each other.

FIG. 3 is an explanatory diagram of a method for generating a radio signal. FIG. 3 shows an example of waveforms of a baseband signal, a transmitting side code signal, a coded signal, a carrier wave, and a radio signal. Voltage and time are shown on each of these vertical and horizontal axes. The baseband signal, the transmitting side code signal, and the coded signal are binary signals represented by "+1" and "-1", respectively. In reality, "+1" corresponds to "(amplitude) / 2" and "-1" corresponds to "-(amplitude) / 2".

As described above, the signal output unit 20 outputs a baseband signal including transmission time information, transmission source information, and coordinate information to the coding unit 22. The baseband signal is an NRZ (Non-Return to Zero) signal.
As described above, the code signal generator 23 outputs the transmission side code signal to the coding unit 22, and in the transmission side code signal, a predetermined waveform corresponding to a predetermined code is periodically repeated. In the example of FIG. 3, the predetermined code is "0100101", the code "0" corresponds to "+1", and the code "1" corresponds to "-1". The period Ts of the transmission-side code signal matches or substantially matches the length of one bit of the baseband signal.

The coding unit 22 encodes the baseband signal by multiplying the baseband signal and the transmitting side code signal. Therefore, the waveform of the encoded signal during the period when the baseband signal indicates "+1" matches the predetermined waveform, and the waveform of the encoded signal during the period when the baseband signal indicates "-1" is positive or negative of the predetermined waveform. Matches the inverted waveform.

The minimum value of the pulse width of the coded signal is a value calculated by dividing the length of one bit of the baseband signal by the code length of a predetermined code. In the following, the minimum value of the pulse width of the coded signal will be referred to as the chip period. The product of the bit rate of the baseband signal and the code length is the chip rate. The tip period Tc is the reciprocal of the tip rate.

The minimum value of the pulse width of the coded signal, that is, the chip period Tc is smaller than the minimum value of the pulse width of the baseband signal, that is, the period of 1 bit of the baseband signal. For binary signals, the spectral width is inversely proportional to the minimum pulse width. Therefore, the coding unit 22 encodes the spectrum of the baseband signal. In the example of FIG. 3, the minimum value of the pulse width of the coded signal is (minimum value of the pulse width of the baseband signal) / 7. Therefore, the spectral width of the coded signal is 7 times the spectral width of the baseband signal.

The carrier wave output by the carrier wave generator 25 is a sine wave as shown in FIG. When the carrier wave is millimeter wave, the frequency of the carrier wave is one frequency in 30 GHz to 300 GHz.

As described above, the superimposition unit 24 generates a superimposition signal transmitted as a radio signal from the transmitter 27 by superimposing the coded signal output by the coding unit 22 on the carrier wave output by the carrier wave generator 25. To do. The waveform of the superimposed signal during the period when the coded signal indicates "+1" matches the waveform of the carrier wave, and the waveform of the superimposed signal during the period when the coded signal indicates "-1" is a waveform obtained by inverting the positive and negative of the waveform of the carrier wave. Matches.
As described above, the amplitude of the superposed signal generated by the superimposing unit 24 is amplified by the amplifier 26, and the superposed signal whose amplitude is amplified is transmitted from the transmitter 27 as a radio signal.

The fixed stations 10b and 10c are configured in the same manner as the fixed stations 10a. In the description of the configuration of the fixed station 10a, the configuration of the fixed station 10b can be described by replacing each of the radio signals A1, A2, and A3 with the radio signals B1, B2, and B3. Similarly, in the description of the configuration of the fixed station 10a, the configuration of the fixed station 10c can be described by replacing each of the radio signals A1, A2, A3 with the radio signals C1, C2, C3.

The frequencies of the carrier waves output by the carrier wave generators 25 of the fixed stations 10a, 10b, and 10c are the same or substantially the same. Further, the codes used in the code signal generators 23 of the fixed stations 10a, 10b, and 10c are the same. Further, the times indicated by the clock units 21 of the fixed stations 10a, 10b, and 10c are the same or substantially the same. The control device 11 repeatedly adjusts these times so that the times indicated by the clock units 21 of the fixed stations 10a, 10b, and 10c match.

The control device 11 instructs the fixed stations 10a, 10b, 10c to transmit the radio signal so that at least two transmitters 27 among the three fixed stations 10a, 10b, 10c do not transmit the radio signal in the same time zone. The transmitter 27 that outputs and transmits the radio signal is changed over time. Therefore, at all times of the day, only one fixed station among the fixed stations 10a, 10b, 10c is transmitting the radio signal, or all of the fixed stations 10a, 10b, 10c are transmitting the radio signal. Is stopped.

The transmitters 27 of the three fixed stations 10a, 10b, and 10c transmit radio signals as follows, for example.
First, the control device 11 outputs a transmission instruction to the signal output unit 20 of the fixed station 10a, and changes the transmitter for transmitting the radio signal to the transmitter 27 of the fixed station 10a. The transmitter 27 of the fixed station 10a transmits the radio signals A1, A2, and A3 in this order.

After the radio signal A3 is transmitted, the control device 11 outputs a stop instruction to the signal output unit 20 of the fixed station 10a. After that, the control device 11 outputs a transmission instruction to the signal output unit 20 of the fixed station 10b, and changes the transmitter for transmitting the radio signal to the transmitter 27 of the fixed station 10b. The transmitter 27 of the fixed station 10b transmits the radio signals B1, B2, and B3 in this order.
After the radio signal B3 is transmitted, the control device 11 outputs a stop instruction to the signal output unit 20 of the fixed station 10b. After that, the control device 11 outputs a transmission instruction to the signal output unit 20 of the fixed station 10c, and changes the transmitter for transmitting the radio signal to the transmitter 27 of the fixed station 10c. The transmitter 27 of the fixed station 10c transmits the radio signals C1, C2, and C3 in this order.
After the radio signal C3 is transmitted, the control device 11 outputs a stop instruction to the signal output unit 20 of the fixed station 10c. After that, the control device 11 outputs the transmission instruction again to the signal output unit 20 of the fixed station 10a.

The signal output units 20 of the fixed stations 10a, 10b, and 10c each stop the output of the baseband signal when three times the predetermined time described above has elapsed after the transmission instruction is input from the control device 11. It may be configured as follows. In this case, the control device 11 may output a transmission instruction each time three times a predetermined time elapses. The control device 11 outputs transmission instructions in the order of the signal output units 20 of the fixed stations 10a, 10b, and 10c.

FIG. 4 is a block diagram showing a main configuration of the mobile station 12. The mobile station 12 includes a receiver 40, an amplifier 41, a mixer 42, an oscillator 43, a low-pass filter (hereinafter referred to as LPF) 44, a decoding unit 45, a reception detection unit 46, a code signal generator 47, an arithmetic unit 48, and a clock unit. It has 49, a timer 50, an output unit 51, and a storage unit 52.

The receiver 40 receives the radio signal transmitted by the transmitter 27 of the fixed stations 10a, 10b, and 10c, and outputs the received radio signal to the amplifier 41. The receiver 40 has a dipole antenna or a microstrip antenna.

In the dipole antenna, two conductors protrude from the end face of the cable, and each of the two conductors has an L shape. The positions of the protruding ends of each of the two conductors are symmetrical with respect to the axis of the cable at the end face.
In a microstrip antenna, a circular, elliptical, or rectangular resonance element is installed on a thin printed circuit board with copper foil. A substrate having a low dielectric constant is used as a printed circuit board.

The receiver 40 receives a radio signal using a dipole antenna or a microstrip antenna. Therefore, since the directivity of the receiver 40 is wide, there is a high probability that the radio signal transmitted by the transmitters 27 of the fixed stations 10a, 10b, and 10c will be received.
The reception band of the radio signal of the receiver 40 is a part or the whole of the frequency band (30 GHz to 300 GHz) corresponding to the millimeter wave.

The amplifier 41 amplifies the amplitude of the radio signal received from the receiver 40, and outputs the amplified radio signal to the mixer 42.
The oscillator 43 outputs a sine wave to the mixer 42.

The mixer 42 generates a mixed signal including a coded signal by mixing the radio signal input from the amplifier 41 and the sine wave output from the oscillator 43. The frequency of the sine wave output by the oscillator 43 is, for example, the same as the frequency of the carrier wave output by the carrier wave generator 25 of the fixed stations 10a, 10b, 10c. The mixer 42 outputs the generated mixing signal to the LPF 44.

The LPF 44 extracts a coded signal from the mixed signal input from the mixer 42, and outputs the extracted coded signal to the decoding unit 45 and the reception detection unit 46. The mixer 42 and LPF 44 function as an extractor.

The code signal generator 47 outputs a receiving side code signal corresponding to a predetermined code to the decoding unit 45, similarly to the code signal generators 23 of the fixed stations 10a, 10b, and 10c, respectively. The code used in the code signal generator 47 is the same as the code used in the code signal generator 23 of the fixed stations 10a, 10b, 10c. The receiving-side code signal is a signal in which a predetermined waveform corresponding to a predetermined code is periodically repeated, similarly to the transmitting-side code signal. The predetermined waveform and period are the same for each of the receiving side code signal and the transmitting side code signal.
The code used in the code signal generators 23 and 47 is, for example, a PN (Pseudo Noise) code.

The decoding unit 45 multiplies the receiving side code signal and the coded signal in a state where the receiving side code signal input from the code signal generator 47 and the coded signal input from the LPF 44 are in phase with each other. Thereby, the spectrum of the coded signal input from the LPF44 is despread. As a result, the coded signal extracted by the LPF44 is decoded into a baseband signal.

FIG. 5 is an explanatory diagram of decoding to a baseband signal. In the following, the signal obtained by multiplying the receiving side coded signal and the coded signal will be referred to as a multiplication signal. FIG. 5 shows an example of waveforms of the coded signal, the receiving side coded signal, and the multiplication signal. Voltage and time are shown on each of these vertical and horizontal axes. The receiving side code signal, the receiving side code signal, and the multiplication signal are binary signals represented by "+1" and "-1", respectively. In reality, "+1" corresponds to "(amplitude) / 2" and "-1" corresponds to "-(amplitude) / 2".

The decoding unit 45 multiplies the coded signal and the receiving side coded signal. Therefore, the multiplication signal indicates "+1" while the encoded signal and the receiving side encoded signal both indicate "+1" or "-1". Further, among the coded signal and the receiving side coded signal, one of them shows "+1" and the other shows "-1", and the multiplication signal shows "-1".

As shown in FIG. 5, when the phase difference between the coded signal and the receiving side coded signal is not zero, the multiplication signal does not match the baseband signal. At this time, the absolute value of the integrated value calculated by integrating over the period Ts of the receiving side code signal, that is, the correlation value is small. In the example of FIG. 5, the correlation value is 1.
When the phase difference between the coded signal and the receiving side code is zero, the multiplication signal matches the baseband signal and the correlation value is maximum. In the example of FIG. 5, the maximum value of the correlation value coincides with the length of the period Ts.

The decoding unit 45 adjusts the phase difference between the coded signal and the receiving side code to zero while monitoring the correlation value. When the correlation value is maximum, the phase difference is zero. As described above, the minimum value of the pulse width of the coded signal (chip period Ts) is smaller than the minimum value of the pulse width of the baseband signal, and the spectrum width is inversely proportional to the minimum value of the pulse width. Therefore, when the decoding unit 45 performs decoding, the spectrum of the coded signal is despread. In the example of FIG. 5, since the minimum value of the pulse width of the baseband signal is 7 times the minimum value of the pulse width of the coded signal, the spectrum width of the baseband signal is (spectral width of the coded signal) /. 7.

The correlation value increases as the reception strength of the radio signal received by the receiver 40 increases. The decoding unit 45 outputs the decoded baseband signal and the correlation value information indicating the correlation value when the phase difference is zero to the calculation unit 48.

When a radio signal is transmitted from the transmitters 27 of the fixed stations 10a, 10b, and 10c to the receiver 40 of the mobile station 12, the radio signal received by the receiver 40 is directly sent from the transmitter 27 to the receiver 40. In addition to the radio signal that has arrived, there is a possibility that the radio signal that has arrived at the receiver 40 after being reflected by an object such as the walls W1, W2, W3 is included.

When the receiver 40 receives a plurality of radio signals in the same time zone, the decoding unit 45 determines the correlation value information indicating the baseband signal related to the radio signal that was first successfully decoded and the correlation value related to this radio signal. Is output to the calculation unit 48.
Therefore, the decoding unit 45 has a high probability of decoding the coded signal of the radio signal that has reached the receiver 40 directly from the transmitter 27 into a baseband signal.

When the code used by the code signal generators 23 of the fixed stations 10a, 10b, and 10c is different from the code used by the code signal generator 47 of the mobile station 12, the correlation value is small regardless of the phase difference, and the coded signal. Is not decoded into a baseband signal.

When the coded signal is input from the LPF 44, the reception detection unit 46 shown in FIG. 4 detects the reception of the radio signal and notifies the calculation unit 48 that the receiver 40 has received the radio signal.

The calculation unit 48 acquires time information indicating the current time from the clock unit 49. When the calculation unit 48 acquires the time information from the clock unit 49, the time indicated by the time information acquired by the calculation unit 48 substantially coincides with the time at the time of acquisition.
The timer 50 starts and ends timing according to the instruction of the calculation unit 48. The time counting time measured by the timer 50 is read out by the calculation unit 48.

The output unit 51 outputs a position signal including position information indicating the position of the mobile station 12 to the transfer device 13 according to the instruction of the calculation unit 48. As described above, the transport device 13 changes the traveling direction, stops the movement, changes the moving speed, and the like based on the position information included in the position signal input from the output unit 51.

The storage unit 52 is, for example, a non-volatile memory. The control program is stored in the storage unit 52. The calculation unit 48 has a CPU (Central Processing Unit) (not shown), and executes a control program to execute a process including a position calculation process for calculating the position of the mobile station 12.
Various data are stored in the storage unit 52 by the calculation unit 48. Further, the data stored in the storage unit 52 is read out by the calculation unit 48. The storage unit 52 stores information indicating the positions of the fixed stations 10a, 10b, and 10c.

FIG. 6 is a flowchart showing a procedure of processing executed by the calculation unit 48. First, the calculation unit 48 instructs the timer 50 to start counting (step S1), and determines whether or not the reception detection unit 46 has detected the reception of the radio signal (step S2).

When the calculation unit 48 determines that the reception detection unit 46 has detected the reception of the radio signal (S2: YES), the calculation unit 48 together with the transmission time information and the transmission source information included in the baseband signal input from the decoding unit 45. , Acquires the correlation value information input from the decoding unit 45 (step S3). Next, the calculation unit 48 acquires the time information from the clock unit 49 (step S4). Here, the time indicated by the time information acquired by the calculation unit 48 is the reception time of the radio signal.

Next, the calculation unit 48 transmits the radio signal received by the receiver 40 based on the transmission time indicated by the transmission time information acquired in step S3 and the reception time indicated by the time information acquired in step S4. To the receiver 40 of the mobile station 12 is calculated (step S5). The calculation unit 48 calculates, for example, the period from the transmission time to the reception time as the propagation time.

Next, the calculation unit 48 calculates the propagation distance of the radio signal received by the receiver 40 from the source to the receiver 40 of the mobile station 12 based on the propagation time calculated in step S5 (). Step S6). For example, when it is considered that the room is vacuum, the calculation unit 48 calculates the propagation distance by multiplying the propagation time by the propagation speed of the radio signal in the vacuum. The propagation speed of a radio signal in a vacuum is represented by the product of 3 and 10 to the 8th power (unit: m / s). The calculation unit 48 also functions as a distance calculation unit.

Next, the calculation unit 48 stores the correlation value indicated by the correlation information acquired in step S3 and the propagation distance calculated in step S6 in association with the source indicated by the source information acquired in step S3. (Step S7).
FIG. 7 is a chart showing the correlation value and the propagation distance associated with the transmission source. In step S7, for example, as shown in FIG. 7, the calculation unit 48 stores the correlation value Ma1 and the propagation distance La1 in association with the fixed station 10a which is the transmission source.

When the calculation unit 48 determines that the reception detection unit 46 has not detected the reception of the radio signal (S2: NO), or after executing step S7, the time counting time measured by the timer 50 is the reference time. It is determined whether or not it is the above (step S8). When the calculation unit 48 determines that the time counting time is less than the reference time (S8: NO), the calculation unit 48 executes step S2.

The calculation unit 48 stores the correlation value and the propagation time of the radio signal received by the receiver 40 in association with the transmission source until the time counting time becomes equal to or longer than the reference time. As described above, the radio signals A1, A2, A3, B1, B2, B3, C1, C2, and C3 are sequentially transmitted from the fixed stations 10a, 10b, and 10c each time a predetermined time elapses. The reference time is set to, for example, 9 times a predetermined time. As a result, the receiver 40 of the mobile station 12 can receive all of the radio signals A1, A2, A3, B1, B2, B3, C1, C2, and C3 by the time the clock time exceeds the reference time. Is.

When all of the radio signals A1, A2, A3, B1, B2, B3, C1, C2, and C3 are received before the time counting time exceeds the reference time, they are associated with the source as shown in FIG. Nine correlation values and nine propagation distances are stored in the storage unit 52. If, for example, the radio signal B3 does not reach the receiver 40 of the mobile station 12 by the time when the timekeeping time exceeds the reference time, eight correlation values and eight propagation distances are associated with the source. Is stored in the storage unit 52.

When the calculation unit 48 determines that the time counting time is equal to or longer than the reference time (S8: YES), the calculation unit 48 instructs the timer 50 to end the time counting (step S9), and correlates values for each of the fixed stations 10a, 10b, and 10c. Selects the maximum propagation distance (step S10). The calculation unit 48 executes step S10 based on the correlation value and the propagation distance stored in the storage unit 52 before the time counting time becomes equal to or longer than the reference time. For each of the fixed stations 10a, 10b, and 10c, the higher the correlation value, the better the reception state of the radio signal. Therefore, the propagation distance having the maximum correlation value is selected.

For example, it is assumed that the correlation value and the propagation distance are stored in the storage unit 52 as shown in FIG. 7 before the time counting time becomes equal to or longer than the reference time. The calculation unit 48 selects the propagation distance corresponding to the maximum correlation value among the correlation values Ma1, Ma2, and Ma3 for the fixed station 10a. When the correlation value Ma1 is the maximum correlation value, the propagation distance La1 is selected. Similarly, the calculation unit 48 selects the propagation distance corresponding to the maximum correlation value in the correlation values Mb1, Mb2, Mb3 for the fixed station 10b, and the maximum in the correlation values Mc1, Mc2, Mc3 for the fixed station 10c. Select the propagation distance corresponding to the correlation value of.

Next, the calculation unit 48 calculates the position of the mobile station 12 based on the three propagation distances selected in step S10 (step S11). The calculation unit 48 calculates the position of the mobile station 12 by, for example, hyperbolic navigation. It is assumed that the calculation unit 48 selects the propagation distances La1, Lb1, Lc1 corresponding to the fixed stations 10a, 10b, and 10c in step S10. In hyperbolic navigation, the calculation unit 48 indicates the position where the difference in distance between the fixed stations 10a, 10b and 10b is the absolute value of (La1-Lb1) at the coordinates indicating the positions of the fixed stations 10a, 10b and 10c. Draw a hyperbola, draw a second hyperbola showing the position where the difference in distance between the fixed stations 10b and 10c is the absolute value of (Lb1-Lc1), and set the intersection of the first and second hyperbolas to the position of the mobile station 12. Calculate as. The first hyperbola is a hyperbola whose two focal points are the positions of the fixed stations 10a and 10b. The second hyperbola is a hyperbola whose two focal points are the positions of the fixed stations 10b and 10c. The positions of the fixed stations 10a, 10b, and 10c are the positions indicated by the coordinate information included in the baseband signal whose source is the fixed stations 10a, 10b, and 10c.

The calculation unit 48 may calculate the position of the mobile station 12 by another method. For example, the calculation unit 48 draws a circle in which the center is the position of the fixed station 10a and the radius is the propagation distance La1 at the coordinates indicating the positions of the fixed stations 10a, 10b, and 10c, and the center is the position of the fixed station 10b. Draw a circle whose radius is the propagation distance Lb1 and whose center is the position of the fixed station 10c and whose radius is the propagation distance Lc1. Then, the calculation unit 48 may calculate the intersection of the three circles as the position of the mobile station 12.
The calculation unit 48 also functions as a position calculation unit.

Next, the calculation unit 48 instructs the output unit 51 to output a position signal including the position information indicating the position calculated in step S11 to the transfer device 13 (step S12).
After executing step S12, the calculation unit 48 ends the process. After completing the process, the calculation unit 48 executes step S1 again and repeats the calculation of the position of the mobile station 12.

In the positioning system 1 configured as described above, since the carrier wave of the radio signal transmitted by the transmitters 27 of the fixed stations 10a, 10b, and 10c is millimeter waves, the radio signal having a high chip rate is transmitted to the mobile station 12. can do. By lengthening the code length while maintaining the period Ts in the transmitting side code signal, the chip period Tc is shortened and the chip rate of the coded signal is increased.

When the chip rate is high, the chip period Tc is short, so that when the receiver 40 of the mobile station 12 receives a plurality of radio signals in the same time zone, the decoding unit 45 moves the walls W1, W2, W3, etc. The probability of decoding the coded signal extracted from the radio signal reflected by the wall is low. Therefore, the calculation unit 48 of the mobile station 12 can accurately calculate the position of the mobile station 12.

Further, the carrier wave of the radio signal transmitted by the transmitters 27 of the fixed stations 10a, 10b, and 10c is millimeter wave. Therefore, the radio signal does not spread significantly due to diffraction, and the radio signal transmitted from the transmitters 27 of the fixed stations 10a, 10b, and 10c has a high probability of going straight and reaching the receiver 40 of the mobile station 12. .. As a result, the calculation unit 48 of the mobile station 12 has a low probability of calculating an erroneous position as the position of the mobile station 12.

Further, the transmitters 27 of the fixed stations 10a, 10b, and 10c each have directivity, and the transmission direction of the radio signal is changed with time. Therefore, the probability that the radio signal will reach the mobile station 12 directly from the transmitter 27 is high, and the probability that the radio signal will be reflected by an object such as the walls W1, W2, W3 and reach the mobile station 12 is low.

When the position of the mobile station 12 is the position shown in FIG. 1, when the receiver 40 of the mobile station 12 receives the radio signals B1, B2, B3 from the transmitter 27 of the fixed station 10b, the receiver 40 is walled. There is a possibility of receiving the radio signal B1 reflected by the body W1 and the radio signal B3 reflected by the wall body W2. However, the receiver 40 does not receive the radio signal B2 reflected by an object such as the walls W1, W2, W3. Therefore, the receiver 40 has a low probability of receiving the radio signal reflected by the objects such as the walls W1, W2, and W3.

Further, at least two transmitters 27 in the fixed stations 10a, 10b, 10c do not transmit the radio signal in the same time zone, and the radio signal is transmitted in the transmitter 27 in the fixed stations 10a, 10b, 10c. The transmitter 27 to transmit is changed over time. Therefore, the plurality of radio signals do not interfere with each other, and the transmission time information, the transmission source information, and the like included in the radio signals are appropriately acquired by the calculation unit 48 of the mobile station 12.

(Embodiment 2)
FIG. 8 is a block diagram showing a main configuration of the fixed station 10a according to the second embodiment.
Hereinafter, the difference between the second embodiment and the first embodiment will be described. Since the other configurations other than the configurations described later are common to the first embodiment, the same reference numerals as those of the first embodiment are assigned to the components common to the first embodiment, and the description thereof is omitted. To do.

In the positioning system 1 according to the second embodiment, the configurations of the transmitters 27 of the three fixed stations 10a, 10b, and 10c are different from those of the positioning system 1 according to the first embodiment.

The transmitter 27 of the fixed station 10a has directivity as in the first embodiment, and transmits radio signals A1, A2, and A3 as shown in FIG. The transmitter 27 switches the transmission direction of the radio signal between the first direction, the second direction, and the third direction each time a predetermined time elapses. The transmitting direction of the transmitter 27 is switched in the order of the first direction, the second direction, and the third direction.

The transmitter 27 has an output antenna 60, a reflector 61, and a drive unit 62. The output antenna 60 is connected to the output end of the amplifier 26 from which the superimposed signal is output. The output antenna 60 wirelessly outputs the superimposed signal input from the amplifier 26 by wire to the reflector 61 as a wireless signal. The reflector 61 has a U-shaped cross section and reflects the radio signal output by the output antenna 60 on the inner surface. As a result, a radio signal is transmitted.

The drive unit 62 changes the reflection angle of the radio signal on the reflector 61. As a result, the transmission direction of the radio signal is switched to the first direction, the second direction, or the third direction. The drive unit 62 functions as a change unit.

FIG. 9 is an explanatory diagram of a method of changing the reflection angle of the radio signal. The drive unit 62 is connected to the outside of the reflector 61. The drive unit 62 passes through the connection point with the reflector 61 and rotates the reflector 61 about a straight line perpendicular to the floor surface of the room R. As a result, the reflection angle of the radio signal in the reflector 61 is changed. The straight line perpendicular to the floor surface of the room R is a straight line perpendicular to the paper surface in FIG.

The shape of the cross section of the reflector 61 is not limited to the U shape, and may be, for example, a rectangular shape. Further, as shown in FIG. 9, when the reflector 61 has a cross section in which the inclination changes continuously, the drive unit 62 moves the reflector 61 in a direction parallel to the floor surface of the room R. You may let me. For example, in FIG. 9, the drive unit 62 can change the reflection angle of the radio signal on the reflector 61 by moving the reflector 61 in the vertical direction. The vertical direction in FIG. 9 is one of the directions parallel to the floor surface of the room R.

As described above, the drive unit 62 can continuously transmit radio signals having different transmission directions by changing the reflection angle of the radio signals in the reflector 61.

The transmitters 27 of the fixed stations 10b and 10c are configured in the same manner as the transmitters 27 of the fixed stations 10a. In the description of the configuration of the transmitter 27 of the fixed station 10a, the configuration of the transmitter 27 of the fixed station 10b can be described by replacing each of the radio signals A1, A2, A3 with the radio signals B1, B2, B3. Similarly, in the description of the configuration of the transmitter 27 of the fixed station 10a, the configuration of the transmitter 27 of the fixed station 10c will be described by replacing each of the radio signals A1, A2, A3 with the radio signals C1, C2, C3. Can be done.

The positioning system 1 in the second embodiment similarly exhibits other effects other than the effect obtained by the configuration of the transmitter 27 among the effects performed by the positioning system 1 in the first embodiment.

In the first and second embodiments, the configurations of the transmitters 27 of the fixed stations 10a, 10b, and 10c do not have to be the same. In the first embodiment, at least one of the transmitters 27 of the fixed stations 10a, 10b, and 10c may have a changeover switch 30, three output antennas 31, 32, 33, and a changeover unit 34. Further, in the second embodiment, at least one of the transmitters 27 of the fixed stations 10a, 10b, and 10c may have an output antenna 60, a reflector 61, and a drive unit 62. Therefore, in the first and second embodiments, for example, the transmitter 27 of the fixed station 10a has a changeover switch 30, three output antennas 31, 32, 33 and a changeover unit 34, and the fixed station 10b, Each 10c transmitter 27 may have an output antenna 60, a reflector 61, and a drive unit 62.

(Embodiment 3)
FIG. 10 is a block diagram showing a configuration of a main part of the positioning system 1 according to the third embodiment.
Hereinafter, the differences between the third embodiment and the first embodiment will be described. Since the other configurations other than the configurations described later are common to the first embodiment, the same reference numerals as those of the first embodiment are assigned to the components common to the first embodiment, and the description thereof is omitted. To do.

The positioning system 1 according to the third embodiment includes a fixed station 10d in addition to the components included in the positioning system 1 according to the first embodiment. The fixed station 10d is also fixed at a predetermined position of the room R and is connected to the control device 11 by wire. The positions of the fixed stations 10a, 10b, 10c, and 10d are different from each other. The fixed station 10d also transmits a radio signal to the mobile station 12 according to the instruction of the control device 11. The mobile station 12 calculates the position of its own station based on the radio signals received from the fixed stations 10a, 10b, 10c, and 10d.

The fixed station 10d is configured in the same manner as the fixed station 10a. In the description of the configuration of the fixed station 10a in the first embodiment, the configuration of the fixed station 10d can be described by replacing each of the radio signals A1, A2, A3 with the radio signals D1, D2, D3.

The frequency of the carrier wave output by the carrier wave generator 25 of the fixed station 10d is the same as or substantially the same as the frequency output by the carrier wave generator 25 of each of the fixed stations 10a, 10b, and 10c. Further, the code used in the code signal generator 23 of the fixed station 10d is also the same as the code used in the code signal generator 23 of each of the fixed stations 10a, 10b, and 10c. The control device 11 repeatedly adjusts these times so that the clocks 21 of the fixed stations 10a, 10b, 10c, and 10d match the times.

Similar to the first embodiment, the control device 11 is fixed so that at least two transmitters 27 among the four fixed stations 10a, 10b, 10c, and 10d do not transmit radio signals at the same time zone. The transmitter 27 that outputs the transmission instruction to the stations 10a, 10b, 10c, and 10d and transmits the radio signal is changed over time. Therefore, at all times of the day, only one fixed station among the fixed stations 10a, 10b, 10c, 10d is transmitting the radio signal, or all of the fixed stations 10a, 10b, 10c, 10d are transmitting the radio signal. The transmission of wireless signals is stopped.
The receiver 40 of the mobile station 12 receives the radio signal transmitted by the transmitter 27 of the fixed stations 10a, 10b, 10c, 10d, and the received radio signal is output to the amplifier 41.

The calculation unit 48 of the mobile station 12 performs the same processing as in the first embodiment. The reference time is set to, for example, 12 times a predetermined time. As a result, by the time the time counting time measured by the timer 50 exceeds the reference time, the receiver 40 of the mobile station 12 has the radio signals A1, A2, A3, B1, B2, B3, C1, C2, C3. It is possible to receive all of D1, D2, and D3.

In step S10, the calculation unit 48 selects the propagation distance having the maximum correlation value for each of the fixed stations 10a, 10b, 10c, and 10d. In step S11, the calculation unit 48 calculates the position of the mobile station 12 based on the four propagation times selected in step S10. Here, since the calculation unit 48 uses four propagation distances, it relates not only to the two-dimensional position, that is, the position related to the vertical and horizontal directions in FIG. 10, but also to the three-dimensional position, that is, the vertical, horizontal, and high / low positions. The position can be calculated. The position related to the height is the position in the direction perpendicular to the paper surface of FIG.
The positioning system 1 in the third embodiment has the same effect as that of the first embodiment.

In the third embodiment, when the position calculated by the calculation unit 48 is sufficient in a two-dimensional position, the calculation unit 48 has a correlation value for each of the three fixed stations 10a, 10b, 10c, and 10d. The maximum propagation distance may be selected and the position of the mobile station 12 may be calculated based on the three selected propagation distances. In this configuration, the receiver 40 of the mobile station 12 cannot receive all the radio signals continuously transmitted by one transmitter 27 in the fixed stations 10a, 10b, 10c, and 10d. However, the position of the mobile station 12 is calculated.

Further, the number of fixed stations may be K (K: an integer of 5 or more). When the position calculated by the calculation unit 48 is sufficient in the two-dimensional position, the calculation unit 48 selects and selects the propagation distance having the maximum correlation value for each of the three fixed stations. The position of the mobile station 12 may be calculated based on one propagation distance. In this configuration, all the radio signals continuously transmitted by the transmitters 27 of the (K-3) fixed stations among the K fixed stations are not received by the receiver 40 of the mobile station 12. Even if there is, the position of the mobile station 12 is calculated.

When the position to be calculated by the calculation unit 48 is a three-dimensional position, the calculation unit 48 selects the propagation distance having the maximum correlation value for each of the four fixed stations, and the selected four. The position of the mobile station 12 may be calculated based on the propagation distance. In this configuration, the receiver 40 of the mobile station 12 cannot receive all the radio signals continuously transmitted by the transmitters 27 of the (K-4) fixed stations among the K fixed stations. Even in this case, the position of the mobile station 12 is calculated.
When the number of fixed stations is K, the reference time is set to, for example, 3.K times the predetermined time. "・" Represents a product.
Further, if the position calculated by the calculation unit 38 is a one-dimensional position, the number of fixed stations may be two. In this case, the reference time is set to, for example, 6 times a predetermined time.

In the third embodiment, the configuration of the transmitter 27 is not limited to the configuration including the changeover switch 30, the three output antennas 31, 32, 33, and the changeover unit 34. The transmitter 27 may be configured to include an output antenna 60, a reflector 61, and a drive unit 62. In this case, the positioning system 1 in the third embodiment has the same effect as that in the first embodiment. Further, the configurations of the transmitters 27 of all fixed stations do not have to be the same.

In the first to third embodiments, the number of transmission directions of the radio signal transmitted by the transmitter 27 of the fixed station is not limited to 3, and may be 2 or 4 or more. Also, the number of transmission directions does not have to be the same for all fixed stations. Further, the transmitter 27 of the fixed station does not have to continuously transmit the radio signal. Further, the position of the fixed station may be any position of the indoor R that is different from each other, and is not limited to the corner of the indoor R.
Further, the configuration of the receiver 40 is not limited to a configuration having a dipole antenna or a microstrip antenna, and may be any configuration capable of receiving a radio signal.

Further, the method of calculating the propagation time is not limited to the calculation method based on the transmission time and the reception time of the radio signal. For example, the output of the transmitting side code signal performed by the code signal generator 23 of one fixed station and the output of the receiving side code signal performed by the code signal generator 47 of the mobile station 12 are performed at the same time in the mobile station 12. In, the phase difference between the coded signal and the receiving side coded signal (see FIG. 5) may be calculated as the propagation time.
Further, the correlation value indicated by the correlation value information output by the decoding unit 45 is not limited to the correlation value when the phase difference between the coded signal and the receiving side coded signal is zero, and is not limited to the correlation value of the coded signal and the receiving side coded signal. It may be a correlation value when the phase difference is not zero.

The disclosed embodiments 1 to 3 should be considered as exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of claims, not the meaning described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Positioning system 10a, 10b, 10c, 10d Fixed station 12 Mobile station 22 Coding unit 24 Superimposing unit (generating unit)
27 Transmitter 31, 32, 33, 60 Output antenna 34 Switching unit 40 Receiver 42 Mixer (part of extraction unit)
44 LPF (part of extraction section)
45 Decoding unit 48 Calculation unit (distance calculation unit, position calculation unit)
61 Reflector 62 Drive (change)

Claims (4)

With multiple fixed stations fixed in predetermined positions,
With mobile stations
The mobile station is mounted and equipped with a transport device for transporting workpieces.
Each of the plurality of fixed stations has a transmitter that transmits a radio signal having a carrier wave of millimeter waves.
The mobile station
A receiver that receives a radio signal transmitted by the transmitter of the plurality of fixed stations, and
For the radio signal received by the receiver, a distance calculation unit that calculates the propagation distance from the source to the receiver, and
It has a position calculation unit that calculates the position of its own station based on the propagation distance of a plurality of radio signals having different transmission sources, which is calculated by the distance calculation unit.
The transport apparatus, on the basis of the position information indicating the position of the position calculating unit has calculated in the mobile station, change in the traveling direction, have row changes stop or moving speed of the mobile,
The transmitter of each of the plurality of fixed stations has directivity and continuously transmits the radio signal.
The transmission directions of the wireless signals transmitted continuously are different from each other.
At least one of the transmitters of the plurality of fixed stations
An output antenna that outputs the radio signal and
A reflector that reflects the radio signal output by the output antenna,
With a changing part that changes the reflection angle of the radio signal in the reflector
A positioning system characterized by having. The positioning system according to claim 1, wherein the receiver has a dipole antenna or a microstrip antenna. The transmitters of two or more fixed stations do not transmit the radio signal at the same time zone.
The positioning system according to claim 1 or 2 , wherein the transmitter that transmits the radio signal is changed over time. Each of the plurality of fixed stations
A coding unit that encodes the baseband signal by diffusing the spectrum of the baseband signal based on a predetermined code.
It further has a generation unit that generates the radio signal by superimposing the coded signal encoded by the coding unit on the carrier wave.
The mobile station
An extraction unit that extracts the coded signal from the radio signal received by the receiver, and
Any of claims 1 to 3 , wherein the extraction unit has a decoding unit that decodes the coded signal into the baseband signal by back-diffusing the spectrum of the extracted coded signal. The positioning system described in one.

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