JP2005045747A - Wireless location tracking method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless location tracking method and a wireless location tracking apparatus which attaion a location tracking precisely by a more simplified and inexpensive system. <P>SOLUTION: In a location tracking system 10, which searches the direction of a mobile communication terminal 12, a mobile communication terminal 12a by the same cells calls the mobile communication terminal 12 to be assumed to be located within the same cell, and the mobile communication terminal 12 transmits radio waves to a base station 16 in response to this call. The radio waves transmitted from this mobile communication terminal 12 to the base station are received on a control channel or an information channel by a DOA detector 14, the frequency that the mobile communication terminal 12 uses, is discriminated and the DOA detector 14 then detects or discriminates the direction wherein the transmitted radio waves come. With this method, it is not necessary to change a public radio infrastructure or the like, so that the direction of the target mobile communication terminal can be detected by the simple and inexpensive system. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wireless position tracking method and apparatus, and more particularly to, for example, a portable radio wave direction-of-arrival detector using an electronically controlled waveguide array antenna (hereinafter referred to as “array antenna”) device, The present invention relates to a novel wireless position tracking method and apparatus using a wireless public infrastructure for portable communication terminals such as PHS (Personal Handy-phone System) and PDC (Personal Digital Cellular).

  A wireless position tracking system using PHS or GPS (Global Positioning System) is provided as a commercial service. Examples of these are disclosed in Non-Patent Documents 1 to 4, respectively.

  In a system using PHS, a mobile device measures the signal strength of radio waves transmitted from a plurality of radio base stations, and reports the result to the location information center. In the position information center, the position of the mobile device is specified using a multipoint surveying position specifying algorithm or the like.

In a system using GPS, radio waves from three to four GPS artificial satellites are received and latitude and longitude (altitude as necessary) are calculated.
Tomoyoshi Ohno, Ryuji Yamamoto, Hiroyuki Otsuka “Development of high-precision location information system using PH network” 2000 Shingaku Sodai, B-5-172, Sep. 2000 http: // www. locus. ne. jp Tadashi Shiomi “GPS-based ultra-precision positioning system”, Journal of Science, Vol. 70, no. 5,512-523 May 1987 Ichiro Murata, Ryo Murakami “GPS-Precision Positioning System Using Artificial Satellites” The Geodetic Society of Japan (ed.), Pp121-140 Japan Surveying Association Tokyo 1989

  In a system using PHS, a position accuracy of about 50 m can be obtained if the conditions are good, but the system becomes large and expensive.

  On the other hand, in a system using GPS, the position accuracy can be as high as about 10 m, but a dedicated GPS receiver is required, which is similarly expensive.

  Therefore, a main object of the present invention is to provide a wireless position tracking method and apparatus capable of accurately tracking a position with a simpler and less expensive system.

  The invention of claim 1 is a method of tracking the position of a mobile communication terminal that transmits a response radio wave to a base station in response to a call and then shifts to an information channel, and (a) in the control channel Receive response radio waves, determine the frequency used by the mobile communication terminal, and (b) use the determined frequencies to scan the antenna beam in multiple directions and receive response radio waves to receive signals for each direction. A position tracking method that acquires an intensity, and (c) specifies a direction indicating a maximum received signal intensity as a direction of a mobile communication terminal.

  In the first aspect of the present invention, the response radio wave transmitted from the mobile communication terminal to the base station is received, the frequency is specified, and the direction is determined while scanning the antenna beam at the frequency, so that the wireless public infrastructure can be used as it is. Thus, the position of the mobile communication terminal can be tracked easily and inexpensively.

  In the invention of claim 2, the base station transmits the identification number of the mobile communication terminal to the mobile communication terminal in the general call channel included in the control channel, and step (a) receives (a1) the general call channel. To obtain the identification number sent from the base station to the mobile communication terminal, (a2) receive the broadcast channel included in the control channel and obtain the structure of the control channel, (a3) based on the identification number and the control channel structure The position tracking method according to claim 1, wherein the frequency is specified.

In this claim 2, an identification number (decimal representation (n) of lower 2 octets in the embodiment) is acquired by the general call channel (PCH), and transmitted from the mobile communication terminal to the base station by the report channel (BCCH). Channel structure (in the embodiment, F1 (S) to FNc (S): frequency number (slot number) of intra-zone control channel, NC: number of intra-zone control channel, NP: number of PCH groups per control channel) Based on this decimal number and control channel structure, the slot position used, that is, the frequency of the portable communication terminal is specified. Therefore, the frequency used by the target mobile communication terminal can be accurately specified.

  According to a third aspect of the present invention, the mobile communication terminal transmits a response radio wave to the base station through the dedicated cell channel included in the control channel, and the frequency of the dedicated cell channel is specified in (a3). It is a tracking method.

  According to the third aspect, the frequency of the dedicated cell channel is specified, and accordingly, a response radio wave from the mobile communication terminal to the base station at that frequency is received.

  In claim 5, from the mobile communication terminal to the base station, the incoming radio state report and authentication response, and if necessary, a level measurement response is transmitted as a response radio wave, but in claim 4, at least once, Perform steps (b) and (c).

  According to the sixth aspect of the present invention, a response radio wave is transmitted to the base station via the control channel in response to the outgoing call, and then the position of the mobile communication terminal that shifts to the information channel is tracked using the mobile radio wave arrival direction detector. A position tracking device, a portable radio wave arrival direction detector using an antenna device that can scan the beam direction, frequency discrimination means that receives a response radio wave in the control channel and discriminates the frequency used by the mobile communication terminal, and uses the discriminated frequency The signal strength acquisition means for acquiring the received signal strength for each direction by scanning the antenna beam in multiple directions and receiving the response radio wave, and specifying the direction indicating the maximum received signal strength as the direction of the mobile communication terminal A position tracking device including an orientation specifying means for

  In the sixth aspect, similarly to the first aspect, the direction of the portable communication terminal can be specified by the portable radio wave arrival direction detector.

  The invention according to claim 7 is a method of tracking the position of a mobile communication terminal that transmits a response radio wave to a base station in response to a call and then moves to an information channel, and includes: (a) the control channel Determining the frequency at which the base station transmits a radio channel designation signal to the portable information terminal, and (b) receiving the radio channel designation signal to determine the frequency and slot number used in the information channel of the portable information terminal. (C) at each of the specified frequencies and slot numbers, scan the antenna beam in a plurality of directions and receive a signal transmitted from the portable information terminal to the base station in the information channel. In this position tracking method, received signal strength is acquired, and (d) a direction indicating the maximum received signal strength is specified as the direction of the mobile communication terminal.

  In claim 7, for example, by acquiring the BCCH of the perch channel, the common control channel structure is acquired and the decimal representation of the lower two octets of the incoming identification number of the target portable information terminal (n)) is obtained. In the information channel (TCH), a frequency for transmitting a radio channel designation (SCCH) signal from the base station to the mobile communication terminal is specified. The SCCH is received at this frequency. Since the frequency and slot number that can be used by the target portable information terminal in the information channel (TCH) are designated by the SCCH radio channel designation information, in step (c), the slot number of that frequency is set, and the antenna beam The direction is determined by receiving a signal transmitted from the portable information terminal to the base station while scanning. Therefore, since the wireless public infrastructure can be used as it is, as in the first aspect of the invention, the position of the mobile communication terminal can be tracked easily and inexpensively.

  The invention according to claim 8 is the location tracking method according to claim 7, wherein the portable information terminal transmits a synchronization burst to the base station in response to the radio channel designation signal, and receives the synchronization burst signal in step (c). It is.

  In claim 8, a synchronization burst transmitted from the portable information terminal to the base station is received. Since this synchronization burst is repeatedly transmitted until the mobile information terminal and the base station are synchronized, the position tracking can be reliably performed by using the synchronization burst.

  The base station transmits a call setup signal to the mobile information terminal when synchronization is established by the synchronization burst signal, and the mobile information terminal responds to the call setup signal to the base station by calling the call signal. The position tracking method according to claim 8, wherein step (c) receives a call signal.

  When synchronization is established between the portable information terminal and the base station by the synchronization burst, the base station transmits a call setup (SACCH) signal to the portable information terminal, and in response, the portable information terminal calls the base station (SACCH) signal. However, in claim 9, the direction is determined by receiving the calling signal. Therefore, since the calling signal can be used even if the synchronization burst is removed, the direction can be specified more reliably.

The portable information terminal transmits a synchronization burst to the base station in response to the radio channel designation signal, and the base station sets up a call to the portable information terminal when synchronization is established by the synchronization burst signal. 8. The position tracking method according to claim 7, wherein the mobile information terminal transmits a call signal to the base station in response to the call setup signal, and receives the call signal in step (c).
In the tenth aspect, as in the ninth aspect, since the calling signal can be used even if the synchronization burst is removed, the direction can be specified more reliably.

  The invention according to claim 11 uses a portable radio wave arrival direction detector to track the position of a portable communication terminal that transmits a response radio wave to a base station in response to a call and then shifts to an information channel. A position tracking device, a portable radio wave arrival direction detector, an antenna device capable of scanning a beam direction, a means for determining a frequency at which a base station transmits a radio channel designation signal to a portable information terminal in a control channel, a radio channel designation signal Means for identifying the use frequency and slot number in the information channel of the portable information terminal by receiving the signal, scanning the antenna beam in a plurality of directions at the identified frequency and slot number, and the portable information terminal in the information channel Means for obtaining the received signal strength for each direction by receiving the signal to be transmitted to, and the maximum received signal strength Comprising means for identifying a direction of the mobile communication terminal an azimuth indicating the a location tracking device.

  In claim 11, as in claim 7, the direction of the mobile communication terminal can be specified by the portable radio wave arrival direction detector.

  According to the twelfth aspect of the present invention, a response radio wave is transmitted to the base station via a control channel in response to an outgoing call, and then a call is started by moving to an information channel and operating a call button in the information channel. A method for tracking the position of a communication terminal, comprising: (a) a transmission signal transmitted from a mobile information terminal to a base station before the call button is operated and a mobile information terminal from the base station before the call button is operated The frequency used by the mobile communication terminal is determined by receiving at least one of the transmission signals transmitted to the control channel and at least one of the information channel, and (b) using the determined frequency, a plurality of antenna beams are transmitted. Obtain the received signal strength for each azimuth by scanning the azimuth and receiving the radio wave transmitted from the portable information terminal to the base station. Identifying the orientation as the direction of the mobile communication terminal, a positioning method.

  In the twelfth aspect, the position of the target portable information terminal can be tracked by using the method of the first and / or the seventh aspect until the call button is pressed.

  According to the present invention, the direction of a target mobile communication terminal can be easily detected with a simple and inexpensive system using a wireless public infrastructure.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  A radio location tracking system 10 according to an embodiment of the present invention shown in FIG. 1 is intended for location tracking of, for example, a portable communication terminal 12 which is a PDC, and is a handheld direction of arrival detector (DOA). ) finder): Hereinafter, it may be simply referred to as a “DOA detector”. ) 14 is used to specify the position of the mobile communication terminal 12. As is well known, the portable information terminal 12 is provided with a call button 13, and a call can be made by pressing the call button 13. However, in the present invention, the orientation and position of the portable information terminal 12 are to be specified before the call button 13 of the target portable information terminal 12 is pressed. This is because it is impractical to request the owner of the portable information terminal 12 to press the call button 13 considering that the position tracking of the portable information terminal is typically performed in a disaster relief situation. .

  Specifically, first, (1) another mobile communication terminal 12a is called (calling) that is assumed to be in the same cell. In response to this call, the mobile communication terminal 12 to be tracked transmits radio waves to the base station 16. (2) When the DOA detector 14 receives the radio wave transmitted from the mobile communication terminal 12 to the base station 16, and the DOA detector 14 detects or determines the arrival direction of the radio wave as described later, (3 ) The position of the mobile communication terminal 12 is tracked.

  An example of a DOA detector 14 that can be used in this embodiment is shown in FIGS. The embodiment of FIG. 2 uses a monopole array antenna, and the embodiment of FIG. 3 uses a dipole antenna instead of the monopole antenna.

  Such a DOA detector 14 is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 2003-114468. Here, the DOA detector 14 will be described to the extent necessary for understanding this embodiment.

  The DOA detector 14 includes a cylindrical housing 18 and a hand-held portion 20 that extends downward from the center of the lower surface of the housing 18 and is held by the user. An array antenna device 22 is provided on the upper surface of the housing 18. Specifically, the array antenna device 22 includes a ground conductor 24 disposed at the center of the upper surface of the housing, and one excitation element 26 and a plurality (six in this embodiment) at and around the center. The non-excitation element 28 is disposed. The excitation element 26 and the non-excitation elements 28a to 28f are electrically insulated from the above-described ground conductor 24, as can be seen from FIG. The non-excitation elements 28a to 28f are arranged at intervals of 60 ° with respect to the circumference of the radius R = λ / 4 (λ: wavelength), for example, with the excitation element 26 as the center. In addition, as shown in FIG. 2, a plurality of (in this embodiment, twelve LEDs 30 every 30 °) LEDs 30 are arranged outside the ring-shaped non-exciting elements 28a-28f. This LED 30 is for displaying the determined radio wave arrival direction in correspondence with the direction or position of each non-excitation element 28a-28f.

  As described above, the excitation element 26 of the array antenna device 22 is a 1/4 wavelength antenna element, is electrically insulated from the ground conductor 24, and the non-excitation elements 28a to 28f are variable. The grounding conductor 24 is grounded at high frequency via the reactance element 32. The physical lengths of the exciting element 26 and the non-exciting elements 28a to 28f are set to be the same. For example, when the variable reactance element 32 has inductance (L property), the variable reactance element 32 functions as an extension coil, and the electrical length of the non-excitation element 28 to which the variable reactance element 32 is connected is supplied to the excitation element 26. It becomes longer compared. Therefore, the non-excited element 28 functions as a reflector. On the other hand, when the variable reactance element 32 has a capacitance property (C property), the variable reactance element 32 becomes a shortening capacitor, and the electrical length of the non-excitation element 28 to which the variable reactance element 32 is connected becomes shorter than that of the excitation element 26. Therefore, the non-excitation element 28 functions as a director.

  Therefore, in the array antenna apparatus 22, the plane directivity characteristics of the array antenna apparatus 22 can be changed by changing the reactance values of the variable reactance elements 32 connected to the non-excitation elements 28a to 28f. That is, in the DOA detector 14 of this embodiment, the array antenna device 22 shown in FIG. 2 or 3 is used as a phased array antenna that detects the direction of arrival of radio waves.

  The planar directivity of the array antenna device 22 is shown in FIG. 4, for example. Referring to FIG. 4, in the array antenna apparatus 22 of the embodiment, it can be seen that although the bands are relatively wide as 65 MHz and the frequencies are 893 MHZ, 925 MHz, and 958 MHz, substantially the same directivity can be obtained. As a result of experiments by the inventors, the F / B ratio was 10 dB or more, the gain was 2 dBi or more, and the angle discrimination power was 2 dB at 0 ° and 60 °.

  Further, in the array antenna apparatus of the embodiment shown in FIG. 3, since the feeding port is only one central excitation element, the RF receiving system can be made into one system. Only the variable reactance elements (varactor diodes) and the bias circuit are loaded in the surrounding six non-excited elements. As described above, the capacitance of the variable reactance elements is changed by the applied DC voltage, and the respective elements are coupled. The amount is changed and the signal is electromagnetically synthesized in the space stage. However, since the loaded varactor is operated with a reverse bias, the power consumption can be reduced. The typical element spacing and element length are λ / 4 and λ / 2, respectively. For example, in the case of 925 MHz, the diameter (2R) and height of the annular arrangement of the non-excited elements are 16.2 cm, It is considered to be a size that can be carried with one hand. The beam scanning speed is limited by the CR time constant of the variable reactance element. However, in the case of a commercially available silicon varactor diode (for example, “1SV287”), the value is 17.1 psec. Therefore, high-speed scanning is possible.

  In this way, it is understood that the functions and specifications necessary for a portable radio wave arrival direction detector can be satisfied by using the array antenna device 22 in the DOA detector 14 of the embodiment. However, other types of scanning antennas (phased array antennas) can of course be used.

  As shown in FIG. 5, in the DOA detector 14, the array antenna device 22 (in the embodiment of FIG. 5 is an array antenna device using the dipole antenna element of FIG. 3) from the target portable communication terminal 12 to the base station 16 is used. The received signal that intercepts the response radio wave is input to the LNA (low noise amplifier) 36 via the coaxial cable 34, is amplified, and is input to the mixer 40 via the band-pass filter (BPF) 38. On the other hand, a local oscillation signal from an oscillator 42 is given to the mixer 40. Therefore, the mixer 40 down-converts the received signal into a predetermined intermediate frequency signal. The intermediate frequency signal is amplified by the BPF 44 and the amplifier 46 and detected by the detector 48.

  A detection signal (envelope signal) output from the detector 48 is given to a DSP (Digital Signal Processor) 52 as a digital signal by the A / D converter 50. This digital signal becomes data (RSSI value) indicating the electric field strength of the radio wave received by the array antenna device 22 at that time. The DSP 52 applies a reactance value set to each variable reactance element 32 via the D / A converter 56 in order to change the direction of the main beam as described above.

  Specifically, in this embodiment, each reactance value set for directing the main beam in 12 directions at 30 ° intervals (six reactance values for six variable reactance elements are set as one set. ) Is stored in advance in the ROM 54 as a reactance value set table, and when the main beam is directed in one direction, the DSP 52 reads one reactance value set from the table and passes each reactance value set via the D / A converter 56. The variable reactance element 32 is set.

  When the DSP 52 discriminates or detects the radio wave arrival direction, the DSP 52 lights the LED 30 via the driver 58 and displays the radio wave arrival direction. However, the specific operation of the radio wave arrival direction determination executed by the DSP 52 has been described in detail in the above-mentioned publication, and thus further description thereof is omitted here.

  Although the main specifications of the DOA detector 14 of this embodiment are shown in Table 1, it is natural that the performance of the DOA detector used is not limited to this.

図１の実施例のシステム１０において携帯通信端末１２の位置追跡を行うために必要な条件は、（１）探索対象となる携帯通信端末から継続して電波を送信させること、（２）探索対象となる携帯通信端末の送信周波数とタイムスロットとを特定すること、（３）バッテリ動作が可能なＤＯＡ探知機で探索対象となる携帯通信端末のバースト信号を受信してその方位を特定することである。このうち条件（３）については図２〜図５に示す実施例のＤＯＡ探知機１４で充足されることは先に説明したとおりであり、この点についての繰り返しの説明は省略する。

The conditions necessary for tracking the position of the mobile communication terminal 12 in the system 10 of the embodiment of FIG. 1 are: (1) continuously transmitting radio waves from the mobile communication terminal to be searched; (2) search target (3) By receiving a burst signal of a mobile communication terminal to be searched by a DOA detector capable of battery operation and specifying its orientation. is there. Of these, the condition (3) is satisfied by the DOA detector 14 of the embodiment shown in FIGS. 2 to 5 as described above, and repeated description of this point is omitted.

  Here, FIG. 6 shows a channel configuration (functional channel) of the PDC as the mobile communication terminal 12 used in the embodiment of FIG. In FIG. 1 embodiment, the portable communication terminal 12 functions as a transmitter mainly when the information channel (TCH) is used in a call state. However, as shown in the main specifications of the PDC in Table 2 below, the TCH carrier frequency and the number of time slots are very large, and the carrier frequency and time slot are determined by the radio network controller. Further, considering that mobile station initiative type channel switching occurs, it is difficult to instantaneously specify the TCH frequency and time slot of the mobile communication terminal to be searched.

  On the other hand, since the frequency of the broadcast channel (BCCH) and the common control channel (CCCH) is limited to some extent, it is easy to specify. In the case of a general call channel (PCH), F1 (S) to FNc (S): frequency number (slot number) of the intra-zone control channel, NC: intra-zone control channel, based on the control channel structure information included in the BCCH NP: PCH grouping number per control channel. Furthermore, if the decimal representation of the value of the lower two octets of the mobile station number of the mobile communication terminal to be searched is n, the frequency number IF and the PCH group on which the mobile communication terminal to be searched is waiting from the equation (1) Number IP can be specified. Therefore, the frequency of the dedicated cell channel (SCCH) that is the uplink signal can be specified. Therefore, in the system 10 of this embodiment, the dedicated cell channel (SCCH) is calculated from the frequency number (IF) and the PCH group number (IP) on which the portable communication terminal to be searched is awaited using the equation (1). ) Frequency and slot number.

なお、ユーザパケットチャネル（ＵＰＣＨ）に関しては、同様にその周波数は特定できるが、タイムスロットを特定することが困難なため、位置追跡システムには適応しないと考えられる。

As for the user packet channel (UPCH), the frequency can be specified in the same manner, but it is difficult to specify the time slot, so it is considered that it is not applicable to the position tracking system.

  Furthermore, a control sequence in which the mobile communication terminal transmits radio waves to the base station using SCCH is transmission, reception, location registration, packet transmission, packet reception, and the like. In particular, for incoming calls, as shown in FIG. 7, 0.5 sec. Incoming radio status report (SCCH) is transmitted within, followed by an authentication response (SCCH) to the authentication request (SCCH) from the base station, and optionally a level measurement response to the level measurement request (SCCH) from the base station (SCCH) is transmitted. By repeating this procedure, burst signals are continuously transmitted from the mobile communication terminal 12. Furthermore, since the SCCH is a control sequence before shifting to the information channel TCH, the disaster victim carrying the mobile communication terminal to be searched transmits radio waves even if he / she does not respond to the call. Therefore, in this embodiment, the SCCH frequency and slot number assigned to the target mobile communication terminal 12 are specified by intercepting a burst signal (response signal), and the arrival of the radio wave is performed by the method described above. The position of the target mobile communication terminal 12 is tracked by searching for the direction.

  A position tracking control sequence in the system 10 of the embodiment of FIG. 1 is shown in FIG. 7, and its operation flowchart is shown in FIGS. 8 and 10, respectively.

  First, in the first step S1 of FIG. 8, another mobile communication terminal 12a shown in FIG. 1 calls (transmits) the mobile communication terminal 12 to be searched. Then, the mobile communication terminal 12 to be searched is called by a call (PCH) via the radio base station 16. Therefore, in the next step S2, the DOA detector 14 also receives the PCH and obtains an incoming call identification number temporarily given to the mobile communication terminal 12 to be searched. That is, in this step S2, the DSP 52 of the DOA detector 14 obtains a decimal representation (n) of the value of the lower 2 octets (8-bit bytes) of the identification number.

On the other hand, the mobile communication terminal 12 to be searched transmits an incoming radio state report using BCCH in response to a call from the radio base station 16. The response by this broadcast channel functions as a beacon transmitted to all directions of the mobile communication terminal to be searched. Therefore, in step S3, the DOA detector 14 intercepts the BCCH transmitted from the target mobile communication terminal 12, and the structure of the control channel (CCH), that is, F1 (S) to FNc (S): intra-zone control. Channel frequency number (slot number), NC: number of intra-zone control channels, NP: PCH grouping number per control channel.
The DSP 52 of the DOA detector 14 executes the calculation according to the equation (1) shown above in step S4, and in step S5, the DSP 52 executes the calculation of the equation (1), and the portable communication terminal 12 as a target. Obtains the frequency and slot number of the general call channel (PCH) on which is waiting.

  FIG. 9 shows an example of time slots specified according to the embodiment of FIG. 8. In the example shown in FIG. 9, assuming that NC = 3 and NP = 3, the PCH is divided into NC × NP = 9 groups. Accordingly, when the identification number (mobile station number) n = 9 is calculated by the equation (1), n ′ = 9, NC = 3, NP = 3, and the slot number FNc (S) of the target mobile communication terminal 12 is “P9” shown in FIG.

  In this way, the DOA detector 14 can know the SCCH frequency of the target mobile communication terminal 12. Therefore, in the next step S6, the DOA detector 14 sets the reception frequency to the frequency of the SCCH transmitted by the mobile communication terminal to be searched, and thereafter tracks the position of the target mobile communication terminal 12 according to FIG. To do. However, although not shown in FIG. 5, the frequency can be accurately set by providing a PLL (phase locked loop) in the DSP 52.

  In FIG. 10, first, the DOA detector 14 intercepts the radio wave of the incoming wireless state report (FIG. 7) from the target mobile communication terminal 12 and tracks the position of the target mobile communication terminal 12. The first step S11 in FIG. 10 is triggered by the rise of PCH as a trigger. In this step S11, first, the SCCH time when the previously set SCCH incoming call identification number matches that of the target mobile communication terminal 12 is used. A range (for example, 0.5 sec.) Is designated. In step S12, this time is 0.5 sec. Receive radio status report sent within. In other words, the reactance value sets are sequentially read out one by one from the reactance value set table set in the ROM 54 by the DSP 52 (FIG. 5) of the DOA detector 14 by the method described above, via the D / A converter 56. By setting each variable reactance element, received signal strengths in 12 directions are obtained. The received signal strength (RSSI value) for each azimuth is stored in a buffer (not shown) each time, and then compared with each other, and the azimuth showing the maximum strength is estimated as the radio wave arrival direction. In step S13, one of the 12 LEDs 30 (FIG. 2) for displaying the direction of arrival is driven according to the estimation result. However, the display method is not limited to this.

  Next, the DOA detector 14 intercepts the radio wave of the authentication response shown in FIG. 7 from the mobile communication terminal 12 and tracks the position of the mobile communication terminal 12 in steps S14 to S16. The specific method is the same as in steps S11 to S13, but here, in step S14, the mobile station number included in the layer 2 part of the SCCH is used for the selection of the SCCH. That is, in this step S14, the SCCH time range in which the mobile station number included in the layer 2 part matches the target mobile communication terminal 12 is specified, and in the next step S15, the same as the previous step S12, Estimate the direction of arrival of radio waves. In step S16, the estimated azimuth is displayed by an LED.

  Further, the DOA detector 14 also performs steps S17 to S19 by intercepting the radio waves in the level measurement response shown in FIG. 7 of the target mobile communication terminal 12, and estimates and displays the direction. However, steps S17 to S19 are exactly the same as the previous steps S14 to S16, and therefore redundant description is omitted here.

  In this way, in the embodiment of FIG. 1, when the DOA detector 14 intercepts the response radio wave transmitted from the target mobile communication terminal 12 to the base station 16, the arrival direction of the radio wave, that is, the position of the mobile communication terminal 12 is estimated. To do. The estimated result may be displayed by the LED 30 (FIG. 2). Sometimes, although not shown, for example, a PDA (Personal Digital Assistance) is connected to the DOA detector 14 and displayed on the screen of the PDA. It may be.

  In addition, it is thought that the following performance is calculated | required as the DOA detector 14 used for such a position tracking system. (1) It must be able to perform rapid antenna beam steering and have real-time characteristics. (2) It must be lightweight and battery operated, and be portable. (3) The reception frequency can be set to the SCCH frequency transmitted by the mobile communication terminal. (4) The angular resolution is within 30 °. (4) The receiver has a wide dynamic range and a wide searchable distance. In particular, downsizing the DOA detector 14 is important not only for estimating the direction of arrival of radio waves but also for tracking the position. Further, in order to search in the same cell, it is considered that a detectable distance of at least 500 m is required. Considering the time required for the search, it is desirable that the continuous usable time is about 4 hours.

  On the other hand, in the DOA detector used by the inventors in the experiment, the beam scanning completion time in all 12 directions is 1 msec. Met. The time slot length of the SCCH transmitted by the mobile communication terminal to be searched is, for example, 6.67 msec. Therefore, the DOA detector 14 of the embodiment has sufficient real-time property for direction estimation within one burst. Then, the SCCH frequency used by the target mobile communication terminal 12 can be correctly analyzed and set according to the method of the embodiment. Further, since the size (diameter: 16.2 cm) as described above is provided, the portable device is portable, and the continuous usable time of 4 hours or more is confirmed by the battery drive with the DOA detector used in the experiment.

  As described above, the position tracking system 10 of the embodiment of FIG. 1 uses a portable radio wave direction-of-arrival detector 14, a portable communication terminal such as a PDC, and a wireless public infrastructure therefor, for exclusive use. Since there is no need to use a transceiver or change the public wireless infrastructure, a position tracking system can be realized with a simple configuration and at a low cost.

  However, in the above-described embodiment, another mobile communication terminal 12 a is used to make a call to the target mobile communication terminal 12. However, as shown in FIG. 11, the DOA detector 14 may be provided with such a calling function. That is, as can be seen from the above description, the mobile communication terminal 12 for making a call does not need to talk to the target mobile communication terminal 12 just by calling the target mobile communication terminal 12. It is easy to provide such a calling mechanism in the DOA detector 14.

  In the embodiment of FIG. 11, for example, a calling key 60 including a numeric keypad as in a portable communication terminal is provided, and the DSP 52 gives a command to the calling mechanism 62 according to the key signal. In response, the calling mechanism places a call to the portable communication terminal 12 having the corresponding telephone number, and then the DSP 52 gives a stop command to the calling mechanism 62 when the transmission radio wave from the portable communication terminal 12 can be intercepted. . According to this embodiment, the position of the mobile communication terminal 12 can be tracked only by the DOA detector 14.

  Further, in the embodiment of FIG. 1, tracking is performed by estimating the direction E (γ, θ, φ) of the mobile communication terminal 12. However, if two DOA detectors 14a and 14b are used as in the embodiment shown in FIG. 12, the position of the target mobile communication terminal 12 can be specified by the principle of so-called triangulation. That is, in this embodiment, the two DOA detectors 14a and 14b can obtain different azimuth information (γ1, θ1, φ1) and (γ2, θ2, φ2), respectively, and these two azimuth information and two DOA The position of the mobile communication terminal 12 can be specified based on the distance L between the detectors 14a and 14b.

In the above-described embodiment, because it is difficult to instantaneously specify the TCH frequency and the time slot of the mobile communication terminal, the frequency number (IF) and the PCH group of the PCH group that the mobile communication terminal to be searched for in the PCH is waiting for. The frequency and slot number of the dedicated cell channel (SCCH) are obtained from the number (IP).
However, according to experiments by the inventors, if the radio channel designation (SCCH) transmitted from the base station to the portable information terminal can be intercepted in the TCH, the usable frequency and the slot number of the portable communication terminal that is the search target of the SCCH. Therefore, it was found that the orientation of the portable information terminal 12 can be specified before pressing the call button 13 (FIG. 1) even in TCH.

  More specifically, after the “level measurement response” in FIG. 7, the TCH shifts to the TCH. In this TCH, as shown in FIG. 13, a radio channel designation (SCCH) is transmitted from the base station to the portable information terminal. Then, the portable information terminal repeatedly transmits the synchronization burst to the base station using the frequency and slot number specified by the radio channel designation. This synchronization burst is repeatedly transmitted until synchronization is established between them, for example, until a PLL (phase locked loop) is drawn. Therefore, another embodiment of the present invention seeks to track the position of the portable information terminal by intercepting a synchronization burst repeatedly transmitted from the portable information terminal to the base station in the TCH.

  However, the location of the mobile information terminal can also be tracked on the TCH by receiving or intercepting a paging signal (SACCH) transmitted from the mobile information terminal to the base station after synchronization is established.

  In this embodiment, the radio channel designation signal cannot be intercepted unless the frequency at which the radio channel designation signal is transmitted from the base station to the portable information terminal is first specified in the TCH. By receiving the BCCH of the one-way channel to the portable information terminal and the channel that is first captured when the portable information terminal is turned on, the frequency at which the radio channel designation signal is transmitted is first identified.

  That is, at step S21 in FIG. 14, the BCCH of the perch channel is received using another portable information terminal 12a (FIG. 1), and at step S22, as in the previous step S3 (FIG. 8), the common control channel is received. The structure (Nc, Np) is acquired. Then, in the next step S23, calculation is performed using a part of the same expression (1) as in step S4 (FIG. 8), and in step S24, the radio channel designation signal is transmitted from the base station to the portable information terminal. Specify the frequency.

  Thereafter, in step S25, a call is made from the portable information terminal 12a to the target portable information terminal 12 (FIG. 1), and a radio channel designation signal is received in step S26, whereby the frequency and slot in the TCH of the target portable information terminal 12 are received. Specify a number. In step S27, the frequency and slot number specified in step S26 are set in the DOA detector 14, and the DOA detector 14 (FIG. 1) can receive a signal transmitted by the TCH from the target portable information terminal 12. Like that.

  On the other hand, since the target mobile information terminal 12 is called in step S25, the target mobile information terminal 12 eventually responds to the base station 16 (FIG. 1) as shown in FIG. Will send a synchronous burst. In step S28, the synchronization burst is received or intercepted by waiting on the frequency and slot number set in step S27. However, at this time, as in the previous steps S12, S15, S18 (FIG. 10), etc., this synchronous burst is received while scanning the antenna. That is, the DSP 52 (FIG. 5) of the DOA detector 14 sequentially reads out the reactance value sets one by one from the reactance value set table set in the ROM 54 and sets the reactance value sets to each variable reactance element via the D / A converter 56. Thus, the received signal strength in 12 directions is obtained. The received signal strength (RSSI value) for each azimuth is stored in a buffer (not shown) each time, and then the arrival direction of radio waves is estimated by performing an averaging process or the like. In step S29, for example, one of 12 LEDs 30 (FIG. 2) for displaying the direction of arrival is driven according to the estimation result.

  In this manner, in the embodiment shown in FIGS. 13 and 14, the position of the target portable information terminal 12 can be tracked before the call button 13 is pressed on the TCH.

  However, as described above, the call signal (SACCH) can be used instead of or in combination with the synchronous burst. In this case, naturally, in step S28 in FIG. 14, the call signal is received instead of the synchronous burst while scanning the antenna direction.

FIG. 1 is an illustrative view showing a wireless position tracking system according to an embodiment of the present invention. FIG. 2 is an illustrative view showing a portable radio wave arrival direction (DOA) detector used in the embodiment of FIG. FIG. 3 is an illustrative view showing an array antenna apparatus used in the DOA detector shown in FIG. FIG. 4 is a graph showing the plane directivity of the 7-element monopole array antenna apparatus of FIG. 2 using frequency as a parameter. FIG. 5 is a block diagram showing an internal configuration of the DOA detector shown in FIG. FIG. 6 is an illustrative view showing a channel configuration of the PDC used in the embodiment of FIG. FIG. 7 is an illustrative view showing a position tracking sequence in the FIG. 1 embodiment. FIG. 8 is a flowchart showing the operation of the FIG. 1 embodiment. FIG. 9 is an illustrative view showing a time slot specified according to the embodiment of FIG. FIG. 10 is a flowchart showing the operation of FIG. 1 embodiment. FIG. 11 is a block diagram showing a modification of the DOA detector. FIG. 12 is an illustrative view showing a method of specifying the position of the mobile communication terminal using the embodiment of FIG. FIG. 13 is an illustrative view showing a position tracking sequence in another embodiment of the present invention. FIG. 14 is a flowchart showing the operation of the other embodiment shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Position tracking system 12 ... Target mobile communication terminal 14, 14a, 14b ... DOA detector 16 ... Base station 22 ... Array antenna apparatus 30 ... LED
52 ... DSP

Claims (12)

A method of tracking the position of a mobile communication terminal that transmits a response radio wave to a base station in response to a call and then moves to an information channel,
(a) determining the frequency used by the mobile communication terminal by receiving the response radio wave in the control channel;
(b) using the determined frequency, scan the antenna beam in a plurality of directions and receive the response radio wave to obtain the received signal strength for each direction; and
(c) A position tracking method for specifying the direction indicating the maximum received signal strength as the direction of the mobile communication terminal. The base station transmits an identification number of the mobile communication terminal to the mobile communication terminal in a general call channel included in the control channel,
Step (a) is
(a1) receiving the general call channel and obtaining the identification number sent from the base station to the mobile communication terminal,
(a2) receiving a broadcast channel included in the control channel to obtain a control channel structure;
(a3) The position tracking method according to claim 1, wherein the frequency is specified based on the identification number and the control channel structure. The mobile communication terminal transmits the response radio wave to the base station through a dedicated cell channel included in the control channel,
The position tracking method according to claim 2, wherein in (a3), the frequency of the channel for the dedicated cell is specified.   The portable communication terminal transmits the response radio wave to the base station a plurality of times in the dedicated cell channel, and executes the steps (b) and (c) using at least one of the plurality of response radio waves. The position tracking method according to claim 1.   5. The position tracking method according to claim 4, wherein an incoming radio state report and an authentication response and, if necessary, a level measurement response are transmitted as the response radio wave from the mobile communication terminal to the base station. A position tracking device that uses a portable radio wave direction-of-arrival detector to track the position of a mobile communication terminal that transmits a response radio wave to a base station in response to a call and then moves to an information channel,
The portable radio wave arrival direction detector is an antenna device capable of scanning the beam direction,
A frequency discrimination means for receiving the response radio wave in the control channel and discriminating a frequency used by the mobile communication terminal;
Using the determined frequency, signal strength acquisition means for acquiring the received signal strength for each direction by scanning the antenna beam in a plurality of directions and receiving the response radio wave, and the direction indicating the maximum received signal strength A position tracking device, comprising orientation specifying means for specifying as a direction of the mobile communication terminal. A method of tracking the position of a mobile communication terminal that transmits a response radio wave to a base station in response to a call and then moves to an information channel,
(a) determining a frequency at which the base station transmits a radio channel designation signal to the mobile information terminal in the control channel;
(b) identifying a use frequency and a slot number in the information channel of the portable information terminal by receiving the radio channel designation signal;
(c) Received signal strength for each direction by scanning a beam of an antenna in a plurality of directions at the specified frequency and slot number and receiving a signal transmitted by the portable information terminal to the base station in the information channel And get
(d) A position tracking method for specifying the direction indicating the maximum received signal strength as the direction of the mobile communication terminal. The portable information terminal transmits a synchronization burst to the base station in response to the radio channel designation signal,
The position tracking method according to claim 7, wherein the synchronization burst signal is received in the step (c). The base station transmits a call setup signal to the mobile information terminal when synchronization is established by the synchronization burst signal, and the mobile information terminal sends a call signal to the base station in response to the call setup signal. Send
The position tracking method according to claim 8, wherein the calling signal is received in the step (c). The portable information terminal transmits a synchronization burst to the base station in response to the radio channel designation signal, and the base station sends a call setup signal to the portable information terminal when synchronization is established by the synchronization burst signal. And the portable information terminal transmits a call signal to the base station in response to the call setting signal,
The position tracking method according to claim 7, wherein the call signal is received in the step (c). A position tracking device that uses a portable radio wave direction-of-arrival detector to track the position of a mobile communication terminal that transmits a response radio wave to a base station in response to a call and then moves to an information channel,
The portable radio wave arrival direction detector is an antenna device capable of scanning the beam direction,
Means for determining a frequency at which the base station transmits a radio channel designation signal to the portable information terminal in the control channel;
Means for identifying a use frequency and a slot number in the information channel of the portable information terminal by receiving the radio channel designation signal;
The received signal strength for each direction is obtained by scanning the antenna beam in a plurality of directions at the specified frequency and slot number and receiving a signal transmitted from the portable information terminal to the base station in the information channel. A position tracking device comprising: means; and means for specifying a direction indicating a maximum received signal strength as a direction of the mobile communication terminal. In response to an outgoing call, a response radio wave is transmitted to the base station via the control channel, then the information channel is entered, and the call is started by operating the call button in the information channel, thereby tracking the position of the mobile communication terminal. A method,
(a) a transmission signal transmitted from the portable information terminal to the base station before the call button is operated and a transmission signal transmitted from the base station to the portable information terminal before the call button is operated Determining a frequency used by the mobile communication terminal by at least one of the control channel and the information channel by receiving at least one of
(b) using the determined frequency, scan the antenna beam in a plurality of directions, receive the radio wave transmitted by the portable information terminal to the base station, obtain the received signal strength for each direction, and
(c) A position tracking method for specifying the direction indicating the maximum received signal strength as the direction of the mobile communication terminal.

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