JPH05100005A - Signal transmitting position sensing method using radio signal - Google Patents

Abstract

PURPOSE:To provide a signal transmitting position sensing method using radio signals, with which the antenna is free of any rotary part, the transmitting position is measurable in a short time, and also the position in the direction over the height can be measured. CONSTITUTION:A signal transmitting position sensing method using radio signals comprises a mobile transmitter 14 transmitting electric wave signals of a certain frequency, at least four stationary radio stations 10-13 located in different positions and equipped with signal receiver receiving the electric wave signals, and at least one base station 13. The signals are received by the receivers of the stationary radio stations and passed to the base station 13, and the difference between the electric wave transfer times from the mobile transmitter 14 to the stationary radio stations is measured, and on the basis of the measurement, the position of the mobile transmitter 14 is calculated three- dimensionally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting position detecting method using a radio signal, and more particularly to a method of specifying a transmitting position from a difference in propagation time of radio waves.

[0002]

2. Description of the Related Art As a method for confirming the position of a radio wave transmission source using radio waves, there is a security method described in Japanese Patent Application Laid-Open No. 64-66581 through transmission and reception of radio wave signals. A radio wave signal is transmitted by a transmitter, the radio wave signal is received by one or more omnidirectional antennas, and the position where the electric field strength is maximum is detected while rotating two or more directional antennas. ,
It was a method of applying the principle of the triangulation method to specify the transmission position of the radio signal.

[0003]

However, in the above method, after the signal is once received by the omnidirectional antenna, 2
Since it is necessary to rotate the above directional antenna to detect the transmission of radio waves, a Yagi antenna or the like is used for the antenna, and further, since it has a mechanical rotating portion, there is a drawback that the device becomes large. Also, since the directional antenna is rotated after receiving the radio signal with the omnidirectional antenna,
There is a problem that it takes time to determine the transmission position. Furthermore, in the above method, the position of the transmitter can be detected only in a plane, and when a large number of high-rise buildings are constructed as in recent years and an accident or the like occurs, the floor can be searched. There was a problem that it could not be done and it was inconvenient. The present invention has been made in view of the above circumstances, the antenna has no rotating portion, and the transmitting position can be measured in a short time.
Moreover, it is an object of the present invention to provide a transmission position detecting method using a radio signal which can measure a position in the height direction.

[0004]

A method according to the above-mentioned object.
A transmitting position detecting method using a wireless signal described, a mobile transmitter that emits a radio signal of a predetermined frequency, and at least four fixed radio stations provided with a receiver arranged at a different position to receive the radio signal, At least one base station, and transmits the radio wave signal to the base station after being received by a receiver of each fixed radio station, and a difference in propagation time of radio waves from the mobile transmitter to each fixed radio station. Is measured, and the position of the mobile radio station is three-dimensionally calculated from the measured value. According to a second aspect of the present invention, there is provided a transmitting position detecting method using a wireless signal, wherein one of the fixed wireless stations is a base station. A method for detecting a transmission position using a wireless signal according to claim 3 is the method according to claim 1 or 2, wherein the signal received by the receiver of each fixed wireless station is wired communication, radio communication or optical communication. Is configured to be transmitted to the base station. In the above, the present invention is applicable regardless of whether the radio signal includes a pulse signal and the distance signal is calculated from the propagation delay time of the pulse, or the distance is calculated from the phase shift of the radio wave or the modulated wave. To be done. In addition, it is preferable that the detected position of the mobile transmitter is displayed on a screen such as a cathode ray tube or a liquid crystal display panel in association with a map. For this reason, the map information is previously stored in a memory, and the movement is performed on the map. The position of the mold transmitter is preferably displayed as a dot (bright spot or flashing signal).

[0005]

In the transmitting position detecting method using the radio signals according to the first to third aspects, the mobile transmitter transmits the radio wave signal of the predetermined frequency, and the radio wave signal is received by at least four fixed radio stations. Then, each of the fixed wireless stations immediately transmits the radio signal to the base station. Therefore, the radio wave signal transmitted to the base station is propagated to at least four or more fixed wireless stations and further propagated from the fixed wireless stations to the base station, which requires a propagation time. However, since each fixed wireless station receives a radio signal and propagates to the base station for a fixed time, subtracting this time gives the propagation time of the radio signal from the mobile transmitter to each fixed wireless station. On the other hand, since the propagation speed of radio waves is constant, it is possible to detect the difference in propagation time from the mobile transmitter to at least four fixed wireless stations and the magnitude of each propagation time. The position of the mobile transmitter can be three-dimensionally detected from the magnitude and the propagation velocity of the radio wave (substantially constant). Particularly, in the transmitting position detecting method using the radio signal according to the second aspect, since one fixed wireless station is the base station, the other fixed wireless stations are
More than a station. Further, in the transmission position detecting method using the radio signal according to the third aspect, since the fixed radio station performs signal transmission from the fixed radio station to the base station by wire communication, radio wave communication or optical communication, the propagation is performed. Since the time becomes constant, the time when each fixed wireless station receives the radio signal can be specified very easily.

[0006]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a schematic block diagram of the entire system to which a transmission position detecting method using a radio signal according to an embodiment of the present invention is applied, FIG. 2 is an operation explanatory diagram, and FIG. 3 is a reception time of each radio signal. FIG. 4 is a flow chart showing the relationship.

FIG. 1 shows a system configuration of a transmission position detecting method using a radio signal according to an embodiment of the present invention.
In this embodiment, the first, second and third fixed radio stations 1
It has 0-12 and the base station 13, and the base station 13 also serves as the fourth fixed wireless station. The mobile transmitter 14 internally has a pulse generation circuit, a code signal transmission circuit for identifying the mobile transmitter 14, and a modulation circuit (AM, SSB, FM, PM modulation) for mounting these on a carrier of a specific frequency. Any of them) and an antenna (not shown) for propagating a radio signal composed of the modulated radio wave of a predetermined electric power in the air, and pressing a specific push button switch (or another switch means). The radio signal is emitted by the operation. Although the identification code is a digital code and is arranged immediately after the pulse signal, the identification code signal is omitted in FIG. Further, the pulse signal may be a single pulse, but it is also possible to use a repetitive pulse having a relatively long interval (for example, about 0.01 to 1 second interval). When using a repetitive pulse, the propagation time may be measured for each repetitive pulse and the average value thereof may be calculated, or an analog value (for example, the charging time and voltage of the capacitor and the voltage may be used by using a repetitive signal). (Relationship with) may be measured. The width of the pulse signal is an extremely short interval (for example, 0.01 μs to 1 μs). A carrier wave carrying the pulse signal normally uses a radio wave of about 10 to 1000 MHz according to the pulse width, but a lower frequency or a higher frequency (1 GHz).
Or more). The antenna of the mobile transmitter may be a non-directional antenna such as a helical antenna, a collinear antenna or a GP antenna, or a loop antenna having some directivity.

The first fixed radio station 10 includes a receiving antenna 15 which is an omnidirectional antenna for receiving a radio signal from the mobile transmitter 14, and a receiver 16 connected to the receiving antenna 15. It has a transmitter 17 for propagating the signal received by the receiver 16 to the base station 13. Further, the mobile transmitter 1 is included in the second fixed wireless station 11.
The receiving antenna 18 which is an omnidirectional antenna for receiving the radio wave signal from the receiver 4, the receiver 19 connected to the receiving antenna 18, and the signal received by the receiver 19 are transmitted to the base station 1
3 and the transmission device 20 that propagates to the network. The third fixed wireless station 12 includes a receiving antenna 21 formed of an omnidirectional antenna that receives an emergency radio signal from the mobile transmitter 14, and a receiver 22 connected to the receiving antenna 21. The signal received by the receiver 22 is transmitted to the base station 13
And a transmitting device 23 that propagates to the.

Since it is sufficient for the receivers 16, 19, 22 to receive only the pulse signal of the radio wave emitted from the mobile transmitter 14, for example, the pulse signal is FM-modulated and the identification code is AM-modulated. Or vice versa, it is possible that the receivers 16, 19, 22 do not receive the identification code. The transmitters 17, 20, 2
Since 3 is for transmitting the pulse signal to the base station 13, when carrying by radio waves, frequency conversion is once performed to a different frequency (preferably a high frequency), and each of It is also possible to transmit to the 1st receiver 24, the 2nd receiver 25, and the 3rd receiver 26. Also,
When a wire is used for the transmitters 17, 20, 23, it is preferable to provide a device for amplifying the output to a sufficient size so as not to be attenuated. In this case, the first receiver 2
4, the second receiver 25 and the third receiver 26 are provided with a device for receiving a signal from a wired cable through which a signal is transmitted, shaping the waveform, and converting it into a correct pulse signal.

It is also possible to send the signals received by the receivers 16, 19, 22 to the first receiver 24, the second receiver 25 and the third receiver 26 by optical fibers, and in this case, the signals are transmitted. The devices 17, 20 and 23 are provided with light conversion elements such as light emitting diodes, and the first receiver 24, the second receiver 25 and the third receiver 26 are provided with light receiving elements such as photodiodes and phototransistors. .. Furthermore, the signals received by the receivers 16, 19 and 22 are converted into laser light by the first receiver 2
4, it is also possible to send to the second receiver 25 and the third receiver 26, in which case the transmitting device 17, 20, 23 includes a laser light emitting device, the first receiver 24, the second receiver
The receiver 25 and the third receiver 26 will include a laser light receiving device oriented in a specific direction.

As described above, the base station 13 has the first
A third receiver 24, 25, 26, an omnidirectional receiving antenna 27 for directly receiving the radio waves of the mobile transmitter 14, and a fourth receiver 28 connected to the receiving antenna 27. I have it. When the pulse signal and the identification code are transmitted in the same modulated wave in the radio signal, the fourth receiver may be a receiver including a single detection circuit,
When different modulation methods are used, a detection circuit according to each modulation method is provided inside to discriminate a pulse signal and an identification code signal. The outputs of the first to fourth receivers 24, 25, 26, 28 are transmitted to the arrival time measuring circuit 29, which is measured by the same timer, and the arrival time of each pulse signal is measured and stored in a memory (not shown). It is supposed to do.

On the other hand, a circuit 30 for decoding the identification code from the signal received by the fourth receiver 28 is provided to transmit information to the computer 31, and at the same time, a specific information stored in the CD is stored. Map information 32 is linked to the computer 31. The computer 31 has a CPU, a ROM for storing a necessary program, a ROM and a RAM for storing information therein, and the arrival time measuring circuit 29 and the identification code decoding circuit 30 via an internal interface circuit. It is connected to and takes in the output. In addition, the computer 31 has an indicator 3 such as a cathode ray tube.
3 is connected to display the map and the position of the mobile transmitter 14 which is the final output.

Next, the position detecting method of the system will be described with reference to FIG.
, The fixed radio stations 10, 11 at points A, B, and C are used as the emergency radio signal emitted from P.
12 and a base station 13 acting as a fixed wireless station located at the point Q. In this embodiment, each of the transmitters 17, 20, and 23 is provided with a frequency converter and a transmitter, and the received radio signals are frequency-converted into different frequencies, so that the first receiver 24 and the second receiver are provided. 25 and the third receiver 26. First
Immediately after the fixed radio station 10 receives the radio wave signal, it is frequency-converted and the signal is propagated to the base station 13. The signal received by the second fixed wireless station 11 is also frequency-converted and propagated to the base station 13. Then, the signal received by the third fixed wireless station 12 is also frequency-converted and propagated to the base station 13. The base station 13 receives all of these signals, and when the radio wave signal is a single pulse within a fixed time, the time received by the first to third receivers 24 to 26 and the fourth receiver 28 is built in. It is preferable to measure with a timer and store each time in memory.

Here, from the mobile transmitter 14 to the base station 13
Considering the time until the radio signal propagates up to, as shown in FIGS. 2 and 3, the time for the radio signal to propagate to the base station 13 via the first fixed radio station 10 is (t ₁ + t
_A ) Further, the time required for the radio wave signal to propagate through the second fixed wireless station 11 to the base station 13 is (t ₂ + t _B ).
Then, via the third fixed wireless station 12, the base station 1
The time until 3 receives the radio signal is (t ₃ + t _C ). The time when the base station 13 receives the radio wave signal is t ₄ . Note that, in reality, since there is a phase delay of the device, the above (t _A ), (t _B ), and (t _C ) become longer than the actual signal propagation time, and in some cases, a constant delay time is required. It is also possible to have. However, the times (t _A ), (t _B ), and (t _C ) can be easily measured by measuring the mobile transmitter 14 at different specific distance positions.

Therefore, since the reception time of the radio wave signal at the base station 13 and the above (t _A ), (t _B ), (t _C ) are known, point A (x ₁ , y ₁ ,
z ₁ ), B point (x ₂ , y ₂ , z ₂ ), C point (x ₃ ,
y ₃ , z ₃ ) and the fixed wireless stations 10 to 12 and the base station 13 arranged at the point Q (x ₄ , y ₄ , z ₄ ) respectively,
The time when the radio signal emitted from the mobile transmitter 14 at the point (x, y, z) is received can be known. On the other hand, since the velocity of the radio wave propagating in the air is a constant (c), for example, if the difference (t ₁ −t ₄ ) between the reception times at points A and Q is multiplied by the constant (c), point P will be This means that the distance difference between the points A and Q is on the hyperboloid of (t ₁ −t ₄ ) × c. Although there are two hyperboloids, one of them can be determined by comparing the sizes of t ₁ and t ₄ . Next, for example, point B and Q
Since the reception time of the radio signal at the point is known, point P is at B
Will be the difference between the distance from the point, and Q point is (t ₄ -t ₂₎ on one hyperboloid × c, further, the difference between the point P distance from point C and point Q (t ₄ -t ₃ ) It is on one hyperboloid of xc. The intersection point of these hyperboloids is the position of the point P to be obtained. This is because the curve (M) is determined when one hyperboloid intersects with another hyperboloid, and when the hyperboloid intersects another hyperboloid. Since the curve (N) is determined, the curve (M)
It is clear that the point of intersection is the curve (N). Therefore, point A (x ₁ , y ₁ , z ₁ ) and point B (x ₂ , y ₂ ,
z ₂ ), C point (x ₃ , y ₃ , z ₃ ) and Q point (x ₄ , y)
₍₄ , z ₄ ) If the reception time of the radio wave signal is known, the position of the point P (x, y, z) can be three-dimensionally known by making a simultaneous equation, and therefore the computer 31 calculates the position. I am trying.

This state is shown in FIG. 4, and the computer 31 first uses the points A (x ₁ , y ₁ , z ₁ ) and B (x
₂ , y ₂ , z ₂ ), arrival time of radio wave signals at point C (x ₃ , y ₃ , z ₃ ) and point Q (x ₄ , y ₄ , z ₄ ) and their magnitude are calculated (step a). .. Next, as described above, a simultaneous equation is established from these conditions to calculate the oscillation point (point P) of the mobile transmitter 14 (step b), and the map information 32
Is taken into the computer 31 and displayed on it (step c). Then, the person carrying the mobile transmitter 14 is read from the identification code decoded by the identification code decoding circuit 30 and displayed on the display 33 (step d). The information to be read is the person's address,
Display name, contact information, phone number, gender, age, blood type, and other necessary information. In this example,
Although the fixed wireless stations including the base station measure the position of the mobile transmitter 14 at four stations, the present invention is also applicable to the case where a larger number of fixed wireless stations or base stations are provided.

In the above embodiment, radio waves were used to propagate signals from the first to third fixed radio stations 10 to 12 to the base station 13, but optical communication using a laser or the like, wire communication,
It is also possible to carry out by communication using an optical fiber. Note that the position of the mobile transmitter can be specified within a very short time by using the pulse signal, but since the processing of the subsequent computer 31 takes time, there are signals from a plurality of mobile transmitters. In this case, parallel processing cannot be performed. Therefore, it is preferable to switch the memory attached to the arrival time measuring circuit 29 immediately after the transmission of one radio wave signal so that the reception time of each mobile transmitter is stored separately. Furthermore, it is preferable to prepare a plurality of computers to process the radio wave signals of different mobile transmitters emitted in a short time. Furthermore, if a large number of mobile transmitters are used at the same time, interference may occur and the operation may not be smooth. Therefore, it is possible to provide another receiver for each mobile transmitter and interlock so that the mobile transmitter does not operate when a radio wave is transmitted from another mobile transmitter. When the switch of the mobile transmitter is activated, the receiver is activated first and the radio signal can be transmitted only when a specific signal (allocation signal) is received from the base station. In this case, when the radio wave signal including the code signal is a signal having a short pulse property, a large number of mobile transmitters can be mixed at the same frequency, which further saves power. Since it is preferable that the clock of the base station is as accurate as possible, it is preferable to use a clock using a rubidium oscillator, a quartz oscillator placed in a constant temperature bath, or an atomic clock if necessary. ..

Further, a receiver for receiving radio waves (preferably including an identification signal for distinguishing each mobile transmitter) from the base station is attached to the mobile transmitter, and the receiver is the base station. It is also possible to send a position confirmation signal corresponding to a radio signal from the mobile transmitter when receiving a special radio wave from the mobile transmitter. You can check.

It is also possible to equip the mobile transmitter of the above embodiment with a carrying tool such as a cane, for example. Further, a solar battery and a storage battery can be used as a power source of the fixed wireless station, and the fixed wireless station can be installed in a place with good radio wave conditions. Since there is no moving part, the fixed wireless station becomes a maintenance-free fixed wireless station. Also, when a pulse signal is used for the radio wave, a plurality of pulses may be received by the reflecting object. In this case, the arrival time of the first pulse signal is measured. When an error occurs, it is preferable to repeat the experiment to some extent to correct the obstacle.

[0020]

As is apparent from the above description, the transmitting position detecting method using a radio signal according to the first to third aspects does not require a rotary antenna which requires a mechanical device, and therefore the device is not required. It is extremely compact, has few failures, and has a long life. Further, since it is not necessary to use a rotary antenna and signal processing can be performed immediately after receiving a radio wave signal with a fixed antenna, the transmission position of the radio wave signal can be detected in a short time. Furthermore, it is possible to perform three-dimensional measurement of the position where a radio wave signal oscillated, which is impossible with a rotary antenna.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a system that employs a transmission position detecting method using a radio signal according to an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the system.

FIG. 3 is a graph showing the relationship of the reception time of each radio signal.

FIG. 4 is a flowchart showing the operation of the computer.

[Explanation of symbols]

 10 First Fixed Radio Station 11 Second Fixed Radio Station 12 Third Fixed Radio Station 13 Base Station 14 Mobile Transmitter 15 Receiving Antenna 16 Receiver 17 Transmitter 18 Receiving Antenna 19 Receiver 20 Transmitter 21 Receiving Antenna 22 receiver 23 transmitter 24 first receiver 25 second receiver 26 third receiver 27 receiving antenna 28 fourth receiver 29 arrival time measuring circuit 30 identification code decoding circuit 31 computer 32 map information 33 indicator

Claims (3)

[Claims] 1. A mobile transmitter that emits a radio wave signal of a predetermined frequency, at least four fixed radio stations that are arranged at different positions and have a receiver that receives the radio wave signal, and at least one base station. Then, after the radio signal is received by the receiver of each fixed radio station, it is transmitted to the base station, the difference in the propagation time of radio waves from the mobile transmitter to each fixed radio station is measured, and from the measured value Set the position of the mobile radio station to 3
A method for detecting a transmission position using a wireless signal, which is characterized in that it is calculated dimensionally. 2. The transmission position detecting method using a radio signal according to claim 1, wherein one of the fixed radio stations is a base station. 3. A transmission position detection using a radio signal according to claim 1, wherein the signal received by the receiver of each fixed radio station is transmitted to the base station by wire communication, radio wave communication or optical communication. Method.