JP2001066360A - Distance detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and stably measure distance by receiving a radio wave and a sound wave that are transmitted in synchronization and measuring the distance between reception and transmission parts based on the detection time difference between the radio wave and the sound wave. SOLUTION: In a transmission device 1, an antenna 7 for radio wave transmission and an element 8 for sound wave transmission receive modulated radio wave and sound wave carriers, and simultaneously dispatches a transmission radio wave 9 and a transmission sound wave 10. In a reception device 2, after reception is started, a timer 19 is reset, and at the same time a radio wave reception part 15 is set to a radio wave-waiting state. In this state, when a reception radio wave 11 exceeds a specific level, the timer 19 is started, and at the same time a sound wave reception part 17 is set to a sound wave-waiting state. In this state, when a reception sound wave 12 exceeds the specific level, the timer 19 is stopped. After the timer 19 is stopped, an analysis part 20 reads each detection time where each reception level detection signal of the radio and sound waves is detected for measuring delay time, and uses the measured value or the like for analyzing the distance between the transmission and reception devices 1 and 2 according to a specific numerical formula.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a distance detection system for detecting a distance between a base station and a mobile station, for example, in mobile radio communication.

[0002]

2. Description of the Related Art For a conventional distance detection system, PH
A mobile station position detection system in S (Personal Handyphone System) will be described as an example. FIG. 7 is a schematic diagram showing a service area in the PHS. Mobile station 30
Can move freely within a service area 33 composed of wireless zones 32a to 32j covered by a plurality of base stations 31a to 31j, respectively. Where PH
In the conventional position detection system in S, the reception electric field strength of the mobile station 30 and the base stations 31a to 31j is measured in each of the finely divided radio zones 32a to 32j, and the highest level of the reception electric field is measured. The wireless zone (in FIG. 7, the wireless zone 32e) in which the intensity is detected is determined as the current position of the mobile station 30.

FIG. 8 is a block diagram showing a conventional radio station used in FIG. The transmitting side 40 has a control unit 41, a radio unit 42, and a transmitting antenna 43, and the receiving side 5
Radio waves can be transmitted toward zero. On the other hand, the receiving side 50 includes a receiving antenna 51, a radio section 52, and a control section 5.
3 and can receive a radio wave from the transmitting side 40. Here, a reception field strength detection section 54 is provided in the radio section 52 of the reception side 50, and when a reception field strength above a certain level is detected, it is determined that the transmission side 40 is present in its own zone.

[0004]

However, in the position detection system that performs distance detection only by the received electric field strength as described above, it can be confirmed that a mobile station exists in a radio zone of a certain base station. It is difficult to accurately measure the distance between mobile stations. In addition, since the electric field intensity fluctuates due to multiple propagation of radio waves or fading, it is difficult to detect distances with high accuracy and stability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a distance detecting system capable of performing a highly accurate and stable distance measurement between wireless stations irrespective of fluctuations in the received electric field strength.

[0006]

In order to achieve the above object, in a distance detecting system according to the present invention, a transmitting device having means for transmitting a radio wave and a sound wave in synchronism, and transmitting from the transmitting device are provided. A receiving device unit having means for receiving the received radio waves and sound waves, and a unit for measuring a distance to the transmitting device unit based on a detection time difference between the radio waves and the sound waves received by the receiving device unit I have.
Specifically, the receiving device unit includes a radio wave detection unit that detects reception of a radio wave, a sound wave detection unit that detects reception of a sound wave, a timer that measures a detection time difference between the radio wave and the sound wave, and based on the detection time difference. And an analyzer for measuring the distance to the transmitting device.

[0007] Further, the transmitting device section has means for modulating and transmitting a radio wave carrier and a sound wave carrier with a signal to which identification data synchronized with a transmission signal is added, respectively.
A receiving unit configured to detect identification data from the radio wave carrier; a second data detection unit configured to detect identification data from the sonic carrier; and identification data and second data detected by the first data detection unit. It may be configured to include a timer for measuring a detection time difference from the identification data detected by the detection unit, and an analysis unit for measuring a distance to the transmission device based on the detection time difference. Note that a mobile radio communication system including the above-described distance detection system and a mobile station and a base station can also be constructed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a distance detection system according to the present invention will be described with reference to FIGS.
This embodiment shows an example in which the distance detection system of the present invention is applied to a mobile radio communication system. FIG.
1 is a block diagram illustrating a configuration of a distance detection system according to the present embodiment. This distance detection system comprises a transmitting device 1 and a receiving device 2. The transmitting device section 1 includes a transmission control section 3, a radio wave transmitting section 4, a sound wave transmitting section 5, a synchronization circuit 6, a radio wave transmitting antenna 7, and a sound wave transmitting element 8. On the other hand, the receiving unit 2 includes a radio wave receiving antenna 13, a sound wave receiving element 14, a radio wave receiving unit 15, a radio wave detecting unit 16, a sound wave receiving unit 17, a sound wave detecting unit 18, a timer 1
9, an analysis unit 20, and a reception control unit 21.

First, the operation of the transmitting unit 1 will be described. The transmission control unit 3 controls the transmission device unit 1. When transmitting a signal from the transmission unit 1 to the reception unit 2, the transmission control unit 3 transmits a radio wave transmission signal to the radio wave transmission unit 4, and the sound wave transmission unit 5 transmits a sound wave transmission signal. Send in synchronization. The radio wave transmitting unit 4 modulates the radio wave carrier with the radio wave transmitting signal, and the sound wave transmitting unit 5 modulates the sound wave carrier with the sound wave transmitting signal.

Here, both the radio wave transmitting unit 4 and the sound wave transmitting unit 5 are connected to the synchronization circuit 6. This synchronization circuit 6
In order to transmit the radio wave carrier and the sound wave carrier modulated by the radio wave transmitting unit 4 and the sound wave transmitting unit 5 to the radio wave transmitting antenna 7 and the sound wave transmitting element 8 in synchronization with the transmission signal, radio wave transmission is performed. The output operation of the unit 4 and the sound wave transmitting unit 5 is controlled. The transmitting radio wave 9 and the transmitting sound wave 10 are simultaneously transmitted from the radio wave transmitting antenna 7 and the sound wave transmitting element 8 which have received the radio wave carrier and the sound wave carrier. Note that these synchronized transmission radio waves 9 and transmission sound waves 10
It is transmitted intermittently by the synchronization circuit 6. This is to conform to the time division multiple access (TDMA) system. FIG. 2 is a timing chart of each signal in the present embodiment. 2A and 2B show the state of the transmission radio wave 9 and the transmission sound wave 10.

Next, the operation of the receiving unit 2 will be described. FIG. 3 is a flowchart showing the operation of the receiving unit in the present embodiment. In the receiving unit 2, after the reception is started (S61), the timer 19 is reset (S6).
2), and at the same time, the radio wave receiving unit 15 enters a radio wave waiting state (S63). In this state, the radio wave receiving antenna 13
Receives the received radio wave 11 (S64), the radio wave receiving unit 1
5 transmits a radio wave reception level signal to the radio wave detection unit 16. Upon receiving this signal, the radio wave detection unit 16 determines whether the intensity of the radio wave reception level signal is equal to or higher than a predetermined level set in advance (S65). If the level is equal to or higher than the predetermined level, the reception is determined and a radio wave reception level detection signal is transmitted to the timer 19. On the other hand, if it is lower than the predetermined level, the radio wave standby state (S63) is continued. FIGS. 2C and 2E show the state of the received radio wave 11 and the radio wave reception level detection signal.

The timer 19 starts (S66) with the rising of the radio wave reception level detection signal as a trigger, and at the same time, the sound wave receiving section 17 enters a sound wave waiting state (S67). In this state, when the sound wave receiving element 14 receives the received sound wave 12 (S68), the sound wave receiving unit 17
, A sound wave reception level signal is transmitted. Upon receiving this signal, the sound wave detector 18 determines whether the intensity of the sound wave reception level signal is equal to or higher than a predetermined level set in advance (S69). If the level is equal to or higher than the predetermined level, it is determined to be “reception”, and a sound wave reception level detection signal is transmitted to the timer 19. The timer 19 stops (S70) with the rising of the sound wave reception level detection signal as a trigger.
On the other hand, if the level is lower than the predetermined level, the sound wave waiting state (S6)
Continue with 7). The sound wave waiting state (S6)
In 7), if no sound wave is received for a certain period of time, the reception control unit 21 determines that a time-out has occurred, sets the timer 19 to a reset state (S62), and returns to the radio wave standby state (S6).
Return to 3). FIGS. 2D and 2F show the received sound wave 12.
And the state of the sound wave reception level detection signal.

After the timer 19 enters the stop state (S70), the analyzer 20 reads each time when the timer 19 detects the radio wave reception level detection signal and the sound wave reception level detection signal, and measures the delay time Td. I do. The value of this delay time Td is determined by the circuit delay time Tc generated by the circuit difference between the radio wave receiving unit 15 and the sound wave receiving unit 17,
c, the distance x between the transmitting device 1 and the receiving device 2 is analyzed by substituting the parameters into the following equation (1) together with parameters such as the propagation speed Vs (t) of the sound wave in consideration of the ambient temperature t. (S71).

(Equation 1) Note that, from Vc 近似 Vs, the distance x may be approximately obtained by using the following equation (2).

(Equation 2)

Thereafter, the reception unit 2 terminates reception (S7).
The receiving routine (S61 to S72) is repeated until 3).
As described above, according to the present embodiment, the distance between the wireless stations is measured based on the detection delay time caused by the difference between the propagation velocities of the radio waves and the sound waves. Therefore, a highly accurate and stable distance measurement can be performed as compared with the conventional configuration in which the distance is detected only by the received electric field strength.

Next, a second embodiment of the distance detection system according to the present invention will be described with reference to FIGS.
1 to 3 are the same as those in the above-described embodiment, and a description thereof will not be repeated. Here, only differences will be described. FIG. 4 is a block diagram illustrating a configuration of the distance detection system according to the present embodiment. The difference in the circuit configuration between the present embodiment and the above-described embodiment is that the radio wave detecting unit 16 and the sound wave detecting unit 18 that constitute the receiving device unit 2 in the above-described embodiment are respectively replaced by the first
That is, the data detector 22 and the second data detector 23 are used. Hereinafter, the operation of each unit will be described.

First, the operation of the transmitting unit 1 will be described. The difference from the above-described embodiment is that when transmitting the radio wave transmission signal from the transmission control unit 3 to the radio wave transmission unit 4 and transmitting the sound wave transmission signal to the sound wave transmission unit 5 in synchronization with each other, The transmission control unit 3 has means for adding identification data synchronized with a signal. The radio wave transmitting unit 4 modulates the radio wave carrier with the radio wave transmitting signal to which the identification data is added,
Then, modulation of a sound wave carrier is performed by a sound wave transmission signal to which identification data is added.

Here, as in the above-described embodiment, the radio wave transmitting unit 4 and the sound wave transmitting unit 5 are both connected to the synchronization circuit 6, and the radio wave transmitting antenna 7 and the sound wave transmitting element 8
The transmission radio wave 9 and the transmission sound wave 10 are transmitted simultaneously and intermittently. FIG. 5 is a timing chart of each signal in the present embodiment. FIGS. 5G and 5H show the state of the transmission radio wave 9 and the transmission sound wave 10.

Next, the operation of the receiving unit 2 will be described. FIG. 6 is a flowchart showing the operation of the receiving device unit in the present embodiment. In the receiving unit 2, after the start of reception (S81), the timer 19 is reset (S8).
2), and at the same time, the radio wave receiving unit 15 enters a radio wave waiting state (S83). In this state, the radio wave receiving antenna 13
Receives the received radio wave 11 (S84), the radio wave receiving unit 1
5 sends the first identification data to the first data detection unit 22. Upon receiving this data, the first data detection unit determines whether the first identification data matches data set in advance (S85). If they match, it is determined to be “reception” and the first identification data detection signal is sent to the timer 19. On the other hand, if they do not match, the radio wave standby state (S83) is continued. (I) and (k) of FIG. 5 show the state of the received radio wave 11 and the first identification data detection signal.

The timer 19 starts with the rising edge of the first identification data detection signal as a trigger (S86), and at the same time, the sound wave receiving section 17 enters a sound wave waiting state (S87). In this state, when the sound wave receiving element 14 receives the received sound wave 12 (S88), the sound wave receiving unit 17 sends the second identification data to the second data detecting unit 23. Upon receiving this data, the second data detection unit 23 determines whether or not the second identification data matches the preset one (S2).
89). If they match, it is judged as "received" and the second
An identification data detection signal is sent to the timer 19. The timer 19 stops (S90) using the rising edge of the second identification data detection signal as a trigger. On the other hand, if they do not match, the sound wave waiting state (S87) is continued. In the sound wave standby state (S87), if the second identification data is not detected for a certain period of time, the reception control unit 21 determines that a time-out has occurred, resets the timer 19 (S82), and returns to the radio wave standby state (S82). S83)
Return to (J) and (l) of FIG. 5 show the state of the received sound wave 12 and the second identification data detection signal.

After the timer 19 enters the stop state (S90), the analysis unit 20 reads each time when the timer 19 detects the first identification data detection signal and the second identification data detection signal, and calculates a delay time Td Is measured. And
The distance x between the transmitting device 1 and the receiving device 2 is analyzed by using the formula (1) or the formula (2) described in the above embodiment. Thereafter, the receiving unit 2 repeats the reception routine (S81 to S92) until the reception is completed (S93). As described above, in the present embodiment, when radio waves and sound waves are received, reception and non-reception are determined based on the coincidence and non-coincidence of identification data added to the reception and non-reception, instead of determining reception and non-reception based on the level of the reception level. Things. Accordingly, the distance between the wireless stations can be measured even in a situation where transmission and reception between the wireless stations are continuous and radio waves are not interrupted, that is, even during continuous communication.

[0021]

In the distance detection system according to the present invention, radio waves and sound waves are transmitted in synchronization with each other, and the distance between the radio stations is measured based on the detection delay time caused by the difference between the propagation speeds of the received radio waves and sound waves. Therefore, it is not affected by the fluctuation of the received electric field strength. Therefore, a highly accurate and stable distance measurement can be performed as compared with the conventional configuration in which the distance is detected only by the received electric field strength.

Further, a configuration may be adopted in which radio waves and sound waves modulated by a signal to which identification data synchronized with a transmission signal are added are transmitted in synchronization with each other, and the distance between wireless stations is measured from the detection delay time of the identification data. . In this way, when receiving radio waves and sound waves, reception and non-reception are not determined based on the strength of the reception level, but reception and non-reception are determined based on the match or mismatch of identification data added thereto. The distance between wireless stations can be measured even in a situation where transmission and reception between wireless stations are continuous and radio waves are not interrupted, that is, during continuous communication.

Further, a mobile radio communication system including a mobile station and a base station having the above-described distance detection system may be constructed. Thus, if this mobile station is carried by oneself, it is possible to accurately grasp the current position of the user. In addition, in order to accurately manage the current positions of a plurality of personnel, each individual may carry a mobile station. Then, the manager can accurately and collectively manage the current position of each individual having the mobile station, and can issue an appropriate staffing instruction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a distance detection system according to the present invention.

FIG. 2 is a timing chart of each signal in the first embodiment.

FIG. 3 is a flowchart showing a receiving operation in the first embodiment.

FIG. 4 is a block diagram showing a second embodiment of the distance detection system according to the present invention.

FIG. 5 is a timing chart of each signal in the second embodiment.

FIG. 6 is a flowchart illustrating a receiving operation according to the second embodiment.

FIG. 7 is a schematic diagram showing a service area in the PHS.

FIG. 8 is a block diagram showing a conventional radio station used in FIG.

[Description of Signs] 1 Transmitting unit 2 Receiving unit 3 Transmission control unit 4 Radio wave transmitting unit 5 Sound wave transmitting unit 6 Synchronous circuit 7 Radio wave transmitting antenna 8 Sound wave transmitting element 13 Radio wave receiving antenna 14 Sound wave receiving element 15 Radio wave Receiving unit 16 Radio wave detecting unit 17 Sound wave detecting unit 18 Sound wave receiving unit 19 Timer 20 Analyzing unit 21 Reception control unit 22 First data detecting unit 23 Second data detecting unit

Claims (4)

[Claims] 1. A transmitting unit having means for synchronizing and transmitting radio waves and sound waves, a receiving unit having means for receiving radio waves and sound waves transmitted from the transmitting unit, and receiving by the receiving unit Means for measuring the distance to the transmitting device based on the detected time difference between the radio wave and the sound wave. 2. The radio communication apparatus according to claim 1, wherein the receiving unit comprises: a radio wave detecting unit for detecting reception of a radio wave; a sound wave detecting unit for detecting reception of a sound wave; a timer for measuring a detection time difference between the radio wave and the sound wave; The distance detection system according to claim 1, further comprising: an analysis unit configured to measure a distance to the transmission device unit. 3. The transmitting device section includes means for modulating a radio wave carrier and a sound wave carrier with a signal to which identification data synchronized with a transmission signal is added, and transmitting the modulated radio wave carrier and the radio wave carrier, respectively. A first data detector for detecting identification data from the carrier, a second data detector for detecting identification data from the sonic carrier, identification data detected by the first data detector, and identification data detected by the second data detector. The distance detection system according to claim 1, further comprising: a timer for measuring a detection time difference, and an analysis unit for measuring a distance to the transmission device based on the detection time difference. 4. A mobile radio communication system comprising a mobile station having the distance detection system according to claim 1 and a base station.