Method for locating position of mobile communication terminal, and base station

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a method for locating a mobile communication terminal of a wireless communication system and a base station.

【0002】

[Conventional technology]

Regarding position positioning in wireless communication systems, as disclosed in Japanese Patent Application Laid-Open No. 2001-103540, navigational position information (latitude, longitude, altitude) data has been obtained in advance by GPS (Grobal Positioning System) or the like. Positioning signals are simultaneously transmitted from the three base stations to the mobile communication terminal whose position moves, and the difference in arrival time of each position orientation signal is measured by the mobile communication terminal, and from this time difference and the latitude and longitude information of the base station. There is one that obtains the location information of the mobile communication terminal.

【0003】

In addition, as shown in FIG. 10, two base stations 1a and 1b whose position information has already been determined measure the radio wave arrival direction from the mobile communication terminal 4, respectively, and determine the distance between the base stations 1a and 1b. From the angles D and E in the figure, there is a method of determining the position of the mobile communication terminal using the principle of triangulation. Even if the base station has a function to measure the propagation delay time of the radio wave from the mobile communication terminal 4 instead of the direction detector, the distance between the mobile communication terminal 3 and the base stations 1a and 1b can be calculated from the propagation delay time. By confirming, the lengths of all sides of the triangle formed by the mobile communication terminal 4 and the base stations 1a and 1b are determined, and there is also a method of determining the position of the mobile communication terminal 3.

【0004】

As described above, in the conventional method, in order to calculate the side or angle of the triangle consisting of the base station and the mobile communication terminal, a plurality of base stations are required in the communicable range of the mobile communication terminal. In such a system, there is usually only one base station in the communicable range, and the position of the mobile communication terminal cannot be specified only by measuring one wave. In that case, in order to identify the position of the mobile communication terminal, the system is combined with an independent navigation device such as a GPS device, so that the mobile communication terminal becomes expensive and must receive radio waves from GPS satellites. was there.

【0005】

[Problems to be Solved by the Invention]

The present invention has been made to solve the above problems, and only one base station measures the radio wave of the mobile communication terminal to determine the position of the mobile communication terminal. The purpose is to provide a method of identification.

【0006】

[Means for solving problems]

The method for locating a mobile communication terminal according to the present invention includes a step of transmitting a wireless transmission signal from a base station to the mobile communication terminal, and the mobile communication terminal receiving the wireless transmission signal sends a response signal to the base station. The step of returning, the step of measuring the distance between the base station and the mobile communication terminal from the time difference between the transmission time of the wireless transmission signal and the arrival time of the response signal in the base station, and the response signal It includes a step of measuring the direction of arrival.

【0007】

Further, the base station includes at least two omnidirectional antennas, and measures the arrival direction of the response signal from the time difference of the response signals arriving at each omnidirectional antenna.

【0008】

Further, the base station includes a plurality of directional antennas, and measures the arrival direction of the response signal by comparing the incoming power of the response signal arriving at each directional antenna.

【0009】

Further, the transmission signal is transmission data.

【0010】

Further, the response signal returns after a certain delay time has elapsed after receiving the signal.

【0011】

Further, the base station according to the present invention includes a transmitter that transmits a wireless transmission signal to the mobile communication terminal, a receiver that receives a response signal to the wireless transmission signal emitted from the mobile communication terminal, and the transmission. It includes a distance measuring means for measuring the distance between itself and the mobile communication terminal from the time difference between the signal transmission time and the arrival time of the response signal, and a direction detecting means for measuring the arrival direction of the response signal.

【0012】

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. Hereinafter, Embodiment 1 of the present invention will be described. FIG. 1 is a diagram showing a configuration of a mobile communication system according to the first embodiment of the present invention. In the figure, the base station 1 includes a distance measuring means for measuring the distance of the mobile communication terminal 4 and an orientation measuring device 2a for measuring the orientation, and also transmits a position orientation signal for measuring the distance and the orientation. It is equipped with a transmitter / receiver 3. The base station 1 is, for example, a base station for mobile phones such as PDC, PHS, and IMT-2000, and a base station for car phones. Here, the position orientation signal may be a dedicated signal, but in reality It may be user data to be communicated with. Further, the mobile communication terminal 4 includes a signal detection circuit that detects a position orientation signal from the base station 1 and instructs the transmitter to return a response signal to the position orientation signal.

【0013】

Further, FIG. 2 is a diagram showing an example of a device configuration of the base station 1. In the figure, 5 includes a distance measuring means 6, a control unit that controls each device in the base station 1, and 7a, 7b, 7c, 7d, and 7e are antennas, respectively. 8a, 8b, 8c, respectively 8d receiver, 9a antenna 7a a phase comparator for comparing the phase of the received signal received by the antenna 7b, 9b Anne of antenna 7c and received signals received by the antenna 7d phase 10a and 10b are A / D converters, 11 is an orientation measuring device that measures the arrival direction of the received signal from the outputs of the phase comparators 9a and 9b, and 12 is connected to the antenna 7e for data. It is a transmission / reception device that performs processing for transmitting / receiving and making a call.

【0014】

Further, FIG. 3 is a diagram showing an example of a device configuration of the mobile communication terminal 4. In the figure, 7f is an antenna, 8e is a receiver, 13 is a transmission / reception switch for switching between receiver 8e and transmitter 14, and 15 is a control unit including signal detection means 16.

【0015】

Next, the position positioning method of the position setting system of the mobile terminal of the present invention will be described. In the mobile communication system as shown in FIG. 1, in order to measure the position of the mobile communication terminal 4, the position orientation signal is first transmitted from the transmission / reception device 3 from the transmission / reception device 12 of the base station 1 to the mobile communication terminal 4. At that time, the distance measuring means 6 stores the transmission timing of the position positioning signal.

【0016】

When the mobile communication terminal 4 receives this position orientation signal, the signal detection circuit 16 determines whether or not the received signal is a position orientation signal, and if it is identified as a position orientation signal, the transmitter 14 immediately sends the base station 1 to the transmitter 14. Is instructed to return a response signal. When the response signal is returned from the transmitter 14 of the mobile communication terminal 4 to the base station 1, the received signals received by the antennas 7a, 7b, 7c, 7d of the base station 1 are the receivers 8a, 8b, 8c, The radio frequency is converted from the radio frequency to the intermediate frequency by 8d, and the outputs of the receivers 8a and 8b are input to the phase comparator 9a, the phases of the received signals received by the antennas 7a and 7b are compared, and the phase difference is output.

【0017】

Here, the directional measurement method according to the first embodiment of the present invention will be described. FIG. 4 is a diagram showing the principle of directional measurement in the first embodiment. Antennas 7a and 7b are omnidirectional antennas and are installed at a distance d. Now, if the incoming radio wave 17 reaches the antennas 7a and 7b from the direction forming an angle A from the straight line connecting the antennas 7a and 7b, the antenna 7a is farther than the antenna 7b by the distance dsinA, so that much. A phase shift occurs. The arrival speed c and wavelength λ of the radio wave are known, and if the phase difference is δ, the arrival time difference τ is τ = λδ / 2π. Therefore, the angle A can be obtained from dsinA = c · τ, and the arrival direction of the radio wave can be determined. Can be measured.

【0018】

In the above, the method of measuring the radio wave arrival direction by measuring the phase difference has been shown, but as a matter of course, the radio wave arrival direction may be measured by directly obtaining the arrival time difference of the radio wave.

【0019】

Moreover, since the distance difference dsinA has the same value at angles A and -A, two directions can be considered even with the same time difference, and the directions are uncertain with only two omnidirectional antennas. Therefore, for example, this problem can be solved by providing another pair of omnidirectional antennas 7c and 7d at positions different by 90 degrees.

【0020】

In this way, the phase comparators 9a and 9b compare the phases of the radio waves arriving at each antenna, the A / D converters 10a and 10b convert them into digital signals, and the phase difference digital signal is input to the orientation finder 11. Will be done. The direction measuring device 11 calculates the direction from the phase difference by the method described above, and outputs the result.

【0021】

On the other hand, the radio wave of the received signal arriving at the antenna 7e is input to the transmission / reception device 12, and when this received signal is a response signal to the position positioning signal, the distance measuring means 6 stores the reception timing of the response signal. The time difference from the transmission timing of the position orientation signal is calculated by excluding the delay time and the like associated with the operation of each device measured in advance. Then, the distance between the two is measured from this time difference and the propagation speed of the radio wave.

【0022】

As described above, the position positioning signal may be an independent specific signal, but for example, in the case of a mobile communication system that performs packet communication, the position positioning signal is used in the header part of the packet containing the call voice data. An identification code indicating the presence may be added, and the time difference for distance measurement may be measured from the transmission / reception time of the first bit of the packet to which the identification code is added.

【0023】

Further, although the example in which the directional measuring device 2a and the transmitting / receiving device 3 receive radio waves by separate antennas has been described, the omnidirectional antenna of the directional measuring device 2 may be shared as the antenna of the transmitting / receiving device 3.

【0024】

Further, although the mobile communication terminal 4 that has received the position orientation signal has shown an example of immediately returning a response signal, for example, when the base station and the mobile communication terminal use one frequency, the mobile communication terminal immediately returns. When responds, the mobile communication terminal may transmit during the transmission of the base station, and the base station cannot receive the response signal of the mobile communication terminal. In such a case, the mobile communication terminal returns a response signal with a fixed delay that does not respond for a predetermined time. This relationship is shown in Fig. 5. 19a is the transmission signal of base station 1, 19b is the response signal to the position orientation signal from base station 1, 20 is the propagation delay based on the distance between base station 1 and the mobile communication terminal 4, and 21 is the fixed delay. is there. FIG. 5 (a) shows a case where the response signal 19b from the mobile communication terminal reaches the base station during transmission of the base station without a time delay 21, and FIG. 5 (b) shows a case where a fixed delay 21 is provided at the base. It is a figure when the signal collision between a station 1 and a mobile communication terminal 4 is avoided. When the response signal 19b to the position orientation signal is returned after the fixed delay 21 in this way, the distance is calculated by subtracting the minute of the fixed delay 21 from the time difference measured for the distance measurement. ..

【0025】

As described above, in the first embodiment of the present invention, in the position locating method of the mobile communication terminal, the position locating signal is transmitted from the base station to the mobile communication terminal, and the locating signal is transmitted from the time of transmitting the locating signal. The distance is calculated by measuring the time it takes for the response signal of the mobile communication terminal to reach the base station, and the arrival direction of this response signal is measured using a plurality of omnidirectional antennas. Since the position of the terminal can be measured by only one base station and there is almost no circuit added to the mobile communication terminal, an inexpensive position determination method is provided.

【0026】

Embodiment 2. In the above-described first embodiment, a method of using at least four omnidirectional antennas is shown as a method of measuring the arrival direction of radio waves, but in the second embodiment, a plurality of directional antennas are used. The direction of arrival of radio waves is measured by the combination of incoming power. For other transmission / reception devices, distance measuring means, etc., the same devices as in the first embodiment are used.

【0027】

FIG. 6 is a diagram showing the principle of the method for measuring the arrival direction of radio waves according to the second embodiment of the present invention. In the figure, for example, four directional antennas 18a, 18b, 18c, and 18d are arranged in the perpendicular directions, respectively, and the incoming radio wave 17 is incident on them. Antennas 18b and 18c detect incoming radio waves with antenna sensitivity at points B and C, respectively.

【0028】

FIG. 7 is a diagram showing the characteristics of the directional antennas 18a, 18b, 18c, and 18d in which the horizontal axis is the angle and the vertical axis is the incoming power. The figure shows the case where the main beam direction of the antenna 18b is 0 degrees and the clockwise direction is the positive direction. Points B and C in FIG. 7 correspond to the portions indicated by points B and C in FIG. 6, and the combination of the incoming power of each antenna changes as the radio wave arrival direction changes. Therefore, the incoming power of each directional antenna 18a, 18b, 18c, and 18d can be measured in this way, and the arrival direction of the radio wave can be measured from the combination thereof.

【0029】

FIG. 8 is a block diagram showing the configuration of the directional measuring device 2b when the directional antennas 18a, 18b, 18c, and 18d are used. The same components as in FIG. 2 of the first embodiment are designated by the same reference numerals. The incoming radio waves received by the directional antennas 18a, 18b, 18c, and 18d are converted from the radio frequency to the intermediate frequency by the receivers 8a, 8b, 8c, and 8d, respectively, and A / D converted to the orientation measuring device 11b. Entered. The directional measuring device 11b measures the angle from the combination of the incoming power of each antenna based on the above principle.

【0030】

If the directional measurement does not require much accuracy, the main beam direction of the directional antenna having the maximum incoming power may be used as the radio wave arrival direction as shown in FIG. FIG. 9 shows a case where the main beam direction of the antenna 18c is used as the radio wave arrival direction because the incoming power of the antenna 18c is maximized.

【0031】

Further, although the example in which the azimuth measuring device 2b and the transmitting / receiving device 3 receive radio waves by separate antennas has been described, the directional antenna of the azimuth measuring device 2b may be shared as the antenna of the transmitting / receiving device 3.

【0032】

Further, as shown in the first embodiment, when the base station and the mobile communication terminal communicate using one frequency, a fixed delay that does not respond for a certain period of time is provided in order to avoid a communication collision. It may be configured to return a response signal to the position orientation signal.

【0033】

As described above, in the first embodiment of the present invention, in the position locating method of the mobile communication terminal, the position locating signal is transmitted from the base station to the mobile communication terminal, and the locating signal is transmitted from the time of transmitting the locating signal. The distance is calculated by measuring the time it takes for the response signal of the mobile communication terminal to reach the base station, and the arrival direction of this response signal is measured using a plurality of directional antennas. Since the position of the above can be measured by only one base station and there is almost no circuit added to the mobile communication terminal, an inexpensive position determination method is provided.

【0034】

[Effect of the invention]

As described above, the method for locating a mobile communication terminal according to the present invention includes a step of transmitting a wireless transmission signal from a base station to the mobile communication terminal, and the mobile communication terminal receiving the wireless transmission signal is the base. A step of returning a response signal to the station and a step of measuring the distance between the base station and the mobile communication terminal from the time difference between the transmission time of the radio transmission signal and the arrival time of the response signal at the base station. Since the step of measuring the arrival direction of the response signal is provided, the position of the mobile communication terminal can be measured by only one base station, and there is almost no circuit added to the mobile communication terminal, so that the cost is low. ..

[Simple explanation of drawings]

[Figure 1]

It is a block diagram of the mobile communication system which concerns on Embodiment 1 of this invention.

[Figure 2]

It is a device block diagram of the base station which concerns on Embodiment 1 of this invention.

[Fig. 3]

It is a device block diagram of the mobile communication terminal which concerns on Embodiment 1 of this invention.

[Fig. 4]

It is a figure which shows the principle of the orientation measurement which concerns on Embodiment 1 of this invention.

[Fig. 5]

It is a figure which shows the transmission / reception timing when a certain time delay is provided. (a) It is a figure in the case where the transmitted / received signals collide without providing a certain time delay. (b) It is a figure when a certain time delay is provided and the collision of a transmission / reception signal is avoided.

[Fig. 6]

It is a figure which shows the principle of the orientation measurement which concerns on Embodiment 2 of this invention.

[Fig. 7]

It is a figure which shows the characteristic of each directional antenna which concerns on Embodiment 2 of this invention.

[Fig. 8]

It is a device block diagram of the base station which concerns on Embodiment 2 of this invention.

[Fig. 9]

It is a figure which shows an example of the orientation measurement method which concerns on Embodiment 2 of this invention.

[Fig. 10]

It is a figure which shows the conventional position positioning method.

[Explanation of symbols]

1 base station, 2 directional measuring device, 3 transmitter / receiver, 4 mobile communication terminal, 5 base station control unit, 6 distance measuring means, 7a, 7b, 7c, 7d, 7e omnidirectional antenna, 8a, 8b, 8c, 8d receiver, 9a, 9b phase comparator, 10a, 10b A / D converter, 11a directivity measuring device, 12 transmitter / receiver, 13 transmitter / receiver switch, 14 transmitter, 15 control unit, 16 signal detection means, 17 incoming radio wave , 18a, 18b, 18c, 18d, 18e directional antenna, 19a base station 1 transmit signal, 19b mobile communication terminal 4 response signal, 20 propagation delay, 21 fixed delay.