JP5323423B2 - Direction estimation system, direction estimation method, and direction estimation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely estimate a direction of a mobile communication terminal relative to an electric wave transmitting source such as a cellular base station and the like. <P>SOLUTION: The mobile communication terminal 10 has a function of estimating the direction of the terminal 10 relative to the cellular base station 20 being the electric wave transmitting source. The mobile communication terminal 10 includes: a memory section 12 for storing information representing an electric wave directivity-based relation between directions relative to the cellular base station 20 and electric wave reception states of the terminal 10 in the respective directions; a reception information acquiring section 13 for acquiring information representing the electric wave reception states of the terminal 10; and a direction estimating section 14 for estimating the direction from the information representing the electric wave reception states acquired by the reception information acquiring section 13, based on the information which is stored in the memory section 12 and represents above relation. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a direction estimation system, a direction estimation method, and a direction estimation program for estimating the direction of a mobile communication terminal from a radio wave source.

  Conventionally, in a cellular system (mobile communication system), so-called cellular positioning is performed in which the position of the terminal is estimated using radio waves transmitted and received between the cellular base station and the mobile communication terminal (cellular terminal). . In cellular positioning, radio waves may be received by only one cell depending on the radio wave reception environment of the terminal. In this case, there is a method for estimating the position of the terminal by estimating the distance and direction from the cellular base station to the terminal from the radio wave received by the terminal. In this method, the positioning accuracy depends on the estimation accuracy of the direction of the terminal from the cellular base station.

  RTT 1 station positioning is a method that uses a distance between a cellular base station and a terminal obtained by RTT (Round Trip Time) measurement and a sector ID that identifies the sector. As shown in FIG. 19 (a), the intersection of the arc having the radius between the cellular base station and the terminal as a radius and the sector direction (usually the antenna directing direction or the sector center direction) determined from the sector ID This is an estimated position method. In this method, since only one direction estimation can be performed in one sector, when the terminal is located away from the sector direction, the direction estimation accuracy is deteriorated and the positioning accuracy is also deteriorated.

The improved RTT 1 station positioning is a method proposed for the problem that the accurate direction of the terminal cannot be estimated by the conventional RTT 1 station positioning method. In this method, in order to improve the reception quality in the mobile communication terminal, the direction estimation accuracy is improved using DHO (Diversity Hand Over) in which the terminal simultaneously receives radio waves from a plurality of sectors. In this case, the maximum number of radio waves that can be received simultaneously is called the number of DHO branches. As shown in FIG. 19 (b), when radio waves from adjacent sectors are simultaneously received, three directions can be estimated in one sector by setting the intermediate direction of the two sectors as the estimated direction of the terminal. The positioning accuracy is improved. The above contents are described in Non-Patent Document 1.
J. Borkowski, et al., “Performance of Cell ID + RTT Hybrid Positioning Method for UMTS Radio Networks,” Proc. 5th European Wireless Conf., Pp487-492, Feb. 2004.

In addition, proposals have been made to further improve the positioning accuracy of RTT positioning using a plurality of measurement results. A plurality of sector IDs can be obtained by performing RTT positioning a plurality of times, that is, by receiving radio waves from a sector a plurality of times. By making the observation frequency ratio of each sector the angle ratio with each sector, it is possible to improve the direction estimation accuracy of the terminal (multiple measurement RTT positioning method). For example, as shown in FIG. 3, in the multi-measurement RTT positioning method, as a result of measuring the RTT multiple times, if the ratio of the number of observations of sector 1 and sector 2 is n, the angle that the terminal makes with the center direction of sector 1 The terminal direction can be estimated by setting the ratio between θ ₁ and the angle θ ₂ that the terminal makes with the center direction of the sector 2 to 1 / n.

  Although the multi-measurement RTT positioning method described above improves the estimation accuracy of the terminal direction as compared with the RTT 1-station positioning method or the like, the angle ratio is obtained from the simple ratio of the number of times of radio waves measured from the sector. Therefore, high direction estimation accuracy was not obtained.

  The present invention has been made in view of the above, and a direction estimation system, a direction estimation method, and a direction estimation program capable of estimating the direction of a mobile communication terminal from a radio wave source such as a cellular base station with high accuracy. The purpose is to provide.

In order to achieve the above object, a direction estimation system according to the present invention is a direction estimation system that estimates the direction of a mobile communication terminal from a radio wave source, and the direction from the source and the mobile communication terminal in that direction. A storage unit storing information indicating a relationship based on radio wave directivity with respect to a radio wave reception state, a reception information acquisition unit that acquires information indicating a radio wave reception state of a mobile communication terminal, and a reception information acquisition unit Direction estimation means for estimating a direction based on the information indicating the reception state of the acquired radio wave based on the information indicating the relationship stored in the storage unit, and the transmission source includes radio waves in two transmission directions. The storage unit stores information indicating the relationship between the angle with respect to the two transmission directions and the ratio of the reception intensity of the radio waves in the two transmission directions as information indicating the relationship based on the directivity of the radio waves. And The communication information acquisition means stores in advance information indicating the relationship between the ratio of the number of receptions of radio waves in two transmission directions based on the nature of radio wave fading and the ratio of the reception strengths of radio waves in the two transmission directions. Information indicating the number of receptions of radio waves in two transmission directions of the communication terminal is acquired, and the ratio of the two transmission directions of radio waves in the two transmission directions according to the acquired information is determined based on the relationship. The information indicating the ratio of the radio wave reception intensity is calculated, and the direction estimating means obtains the relationship stored in the storage unit from the information indicating the ratio of the radio wave reception intensity in the two transmission directions acquired by the reception information acquisition means. The direction is estimated based on the indicated information .

  In the direction estimation system according to the present invention, the direction of the mobile communication terminal is estimated based on the relationship based on the directivity of the radio wave between the radio wave source and the radio wave reception state of the mobile communication terminal. Thereby, according to the direction estimation system according to the present invention, the direction of the mobile communication terminal can be estimated with high accuracy.

As this configuration, if estimating the direction from the information indicating a plurality of times of reception state of radio waves, thereby enabling more accurate direction estimation.

According to the configuration of this, since the estimation of the two outgoing wave direction, allowing further accurate direction estimation.

According to the configuration of this, it is possible to appropriately perform the direction estimation from wave two outgoing.

According to the configuration of this, it is possible to acquire information indicating the ratio of easily receiving strength, as a result, it is possible to easily direction estimation.
The reception information acquisition means stores in advance information indicating a relationship between a ratio of the number of reception times of radio waves in two transmission directions and a ratio of reception strengths of radio waves in the two transmission directions having different fading characteristics. In addition, information corresponding to a transmission source among the plurality of pieces of information may be used for calculation of information indicating a ratio of radio wave reception strengths in two transmission directions.

  The direction estimation system obtains the relationship between the angle of the two transmission directions stored in the storage unit and the ratio of the reception intensity of the radio waves in the two transmission directions from the information indicating the reception state of the radio waves acquired by the reception information acquisition unit. It is desirable to further include accuracy estimation means for estimating the accuracy of the direction estimated by the direction estimation means based on the information shown. According to this configuration, since the accuracy of the estimated direction can be obtained, the estimated direction can be used appropriately.

  The transmission source transmits radio waves in three or more transmission directions, and the reception information acquisition means acquires information indicating the reception state of each radio wave in the three or more transmission directions of the mobile communication terminal, and It is desirable to identify the radio waves in the two transmission directions used for direction estimation based on the reception state. According to this configuration, even when the mobile communication terminal can receive radio waves in three or more transmission directions from a predetermined transmission source, the direction can be estimated appropriately.

  By the way, the present invention can be described as an invention of a direction estimation system as described above, and can also be described as an invention of a direction estimation method and a direction estimation program as follows. This is substantially the same invention only in different categories and the like, and has the same operations and effects.

That is, the direction estimation method according to the present invention estimates the direction of a mobile communication terminal from a radio wave source, and the directionality of radio waves between the direction from the source and the reception state of radio waves of the mobile communication terminal in that direction. A direction estimation method by a direction estimation system including a storage unit that stores information indicating a relationship based on a reception information acquisition step of acquiring information indicating a radio wave reception state of a mobile communication terminal, and acquisition in a reception information acquisition step the information indicating the reception state of radio wave, on the basis of the information indicating the stored above relationship in the storage unit, viewed contains a direction estimation step of estimating a direction, a source is radio two outgoing The storage unit stores information indicating the relationship between the angle with respect to the two transmission directions and the ratio of the reception strength of the radio waves in the two transmission directions as information indicating the relationship based on the directivity of the radio waves. In the reception information acquisition step, the mobile communication terminal acquires information indicating the number of receptions of radio waves in two transmission directions, and the ratio of the number of receptions of radio waves in the two transmission directions according to the acquired information From the relationship between the ratio of the number of receptions of radio waves in two transmission directions based on the characteristics of radio wave fading stored in advance and the ratio of the reception strengths of the radio waves in the two transmission directions, the reception intensity of the radio waves in the two transmission directions Based on information indicating a relationship stored in the storage unit from the information indicating the ratio of the reception intensity of the radio waves in the two transmission directions acquired in the reception information acquisition step in the direction estimation step. The direction is estimated .
Further, in the reception information acquisition step, among the information indicating the relationship between the ratio of the number of receptions of radio waves in two transmission directions and the ratio of the reception intensity of the radio waves in the two transmission directions, which are different in pre-stored fading characteristics Information according to the transmission source may be used for calculation of information indicating the ratio of the reception intensity of the radio waves in the two transmission directions.

  In the direction estimation method, from the information indicating the reception state of the radio wave acquired in the reception information acquisition step, the relationship between the angle with respect to the two transmission directions stored in the storage unit and the ratio of the reception intensity of the radio waves in the two transmission directions is obtained. It is desirable to further include an accuracy estimation step for estimating the accuracy of the direction estimated in the direction estimation step based on the information shown.

  The transmission source transmits radio waves in three or more transmission directions. In the reception information acquisition step, the mobile communication terminal acquires information indicating reception status for each radio wave in three or more transmission directions, and It is desirable to identify the radio waves in the two transmission directions used for direction estimation based on the reception state.

A direction estimation program according to the present invention is a direction estimation program that causes a computer to estimate the direction of a mobile communication terminal from a radio wave transmission source, and the direction of the mobile communication terminal in the direction and the direction from the transmission source. Acquired by a storage function that stores information indicating the relationship between the reception state and the radio wave directivity, a reception information acquisition function that acquires information indicating the reception state of the radio wave of the mobile communication terminal, and a reception information acquisition function Based on the information indicating the reception state of the radio wave, based on the information indicating the above relationship stored by the storage function, the computer executes a direction estimation function for estimating the direction , and the transmission source transmits the radio wave in two transmission directions. The memory function uses information indicating the relationship between the angle with respect to the two transmission directions and the ratio of the reception intensity of the radio waves in the two transmission directions, based on the directivity of the radio waves. The reception information acquisition function stores the relationship between the ratio of the number of receptions of radio waves in two transmission directions based on the nature of radio wave fading and the ratio of the reception strengths of radio waves in the two transmission directions in advance. Information indicating the number of receptions of radio waves in the two transmission directions of the mobile communication terminal is acquired, and the information is obtained from the ratio of the number of receptions of radio waves in the two transmission directions according to the acquired information. Based on the relationship, information indicating the ratio of the reception strength of the radio waves in the two transmission directions is calculated, and the direction estimation function is obtained from the information indicating the ratio of the radio wave reception strengths in the two transmission directions acquired by the reception information acquisition function. The direction is estimated based on information indicating the relationship stored in the storage function .
In addition, the reception information acquisition function stores in advance information indicating the relationship between the ratio of the number of receptions of radio waves in two transmission directions and the ratio of the reception intensity of radio waves in the two transmission directions, which have different fading characteristics. In addition, information corresponding to a transmission source among the plurality of pieces of information may be used for calculation of information indicating a ratio of radio wave reception strengths in two transmission directions.

  According to the present invention, since the direction of the mobile communication terminal is estimated based on the relationship between the radio wave source and the radio wave reception state of the mobile communication terminal, the direction of the mobile communication terminal is estimated with high accuracy. The direction can be estimated.

Hereinafter, preferred embodiments of a direction estimation system and a direction estimation method according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows a mobile communication terminal (cellular terminal) 10 that is a direction estimation system according to the present embodiment. The mobile communication terminal 10 can connect to a mobile communication network and perform mobile communication. The mobile communication terminal 10 performs mobile communication by performing wireless communication with any of a plurality of cellular base stations 20 included in the mobile communication network. The mobile communication terminal 10 has a function of estimating the direction of the terminal 10 from the cellular base station 20 (the azimuth angle with respect to the cellular base station 20). The direction is estimated using radio waves transmitted from the cellular base station 20. The estimation of the direction is performed, for example, for the mobile communication terminal 10 to estimate the position of the terminal 10 (positioning).

  The cellular base station 20 is a component in the mobile communication network, and is a radio wave source that transmits radio waves for estimating the direction by the mobile communication terminal 10. The cellular base station 20 is installed with a predetermined position. In addition, information for uniquely identifying the cellular base station 20 such as a cell ID and base station position information is set in the cellular base station 20, and the mobile communication terminal 10 determines the cellular base station 20 based on the information. Can be specified. Further, the cellular base station 20 is sectorized, and a plurality of sectors are set for each direction in which radio waves are transmitted. That is, the cellular base station 20 transmits radio waves in a plurality of different transmission directions. For example, six sectors are set for one cellular base station 20. In this case, the angle from the cellular base station 20 of one sector is 60 °.

  The pilot signal received for communication by the mobile communication terminal 10 includes information specifying the sector such as the sector ID, and the sector is also specified when the mobile communication terminal 10 performs communication. Specifically, as a radio wave used for direction estimation, a pilot signal (broadcast signal) periodically transmitted from the cellular base station 20, a positioning signal, or the like is used. When the positioning signal is used for direction estimation, the cellular base station 20 receives control from the mobile communication terminal 10 or a device in the mobile communication network, and the positioning signal is transmitted at regular intervals (for example, 1 Every second).

  When the mobile communication terminal 10 has a DHO function (that is, there are a plurality of DHO branches), the mobile communication terminal 10 can simultaneously receive radio waves from a plurality of cellular base stations 20 and sectors.

  Here, the principle of direction estimation according to the present invention (an outline of direction estimation in the mobile communication terminal 10 according to the present embodiment) will be described. FIG. 2 shows a graph of the relationship (antenna pattern) between the direction from the cellular base station 20 and the antenna gain in the mobile communication terminal 10 corresponding to the direction. Thus, as a sector antenna used for transmitting radio waves in each sector of the cellular base station 20, a directional antenna having a directivity such that the antenna gain in the mobile communication terminal 10 is higher in the central direction of the sector. Is used. The antenna pattern as described above is a known parameter used for base station design and the like.

  As shown in FIG. 3, it is assumed that the mobile communication terminal 10 is located at a position where radio waves of two adjacent sectors can be received. In this case, as shown in the graph of FIG. 4, the antenna gain is uniquely determined by the direction of mobile communication terminal 10 (from sector base station 20) and the antenna pattern of each sector. That is, if the antenna pattern is known, the direction of the mobile communication terminal 10 can be estimated from the antenna gain ratio of each sector.

  The received power of the mobile communication terminal 10 is determined by the transmission power (from the cellular base station 20), the propagation path loss, and the antenna gain. Since two adjacent sectors are in the same cell, the correlation of the shadow wing of the propagation path is high, and the instantaneous fluctuation characteristics of the propagation path are almost the same, so the propagation loss is considered to be almost the same. Therefore, it is considered that the ratio of the average received power of the signal of each sector received by the mobile communication terminal 10 and the ratio of the antenna gain are the same.

そして、隣接する２つのセクタにおいて、同一端末に対する送信電力が同じであると仮定すると、Ｐ_Ｔ１＝Ｐ_Ｔ２となる。また、伝搬損出も同じと考えられるのでＨ_１＝Ｈ_２となる。つまり、

が成り立つ。なお、ここで、Ｐ_Ｔ１、Ｇ_１、Ｈ_１、Ｐ_Ｒ１は、それぞれ、隣接する２つのセクタの一方のセクタの平均送信電力、アンテナ利得、平均伝搬損失、平均受信電力である。また、Ｐ_Ｔ２、Ｇ_２、Ｈ_２、Ｐ_Ｒ２は、それぞれ、隣接する２つのセクタの他方のセクタの平均送信電力、アンテナ利得、平均伝搬損失、平均受信電力である。従って、移動通信端末１０における、２つのセクタ間の平均受信電力比が求まれば、図４に示す、セルラ基地局２０からの移動通信端末１０の方向とセルラ基地局の隣接する２つのセクタからの電波の移動通信端末１０におけるアンテナ利得との関係を利用して、移動通信端末１０の方向の推定が可能になる。 In other words, the average transmission power P _T, antenna gain and G, average propagation loss H, when the average received power P _R, the following equation holds.

Assuming that the transmission power for the same terminal is the same in two adjacent sectors, P _T1 = P _T2 . Further, since propagation loss is considered to be the same, H ₁ = H ₂ . That means

Holds. Here, P _T1 , G ₁ , H ₁ , _{PR 1} are the average transmission power, antenna gain, average propagation loss, and average reception power of one of the two adjacent sectors, respectively. P _T2 , G ₂ , H ₂ , and PR ₂ are the average transmission power, antenna gain, average propagation loss, and average reception power of the other two adjacent sectors, respectively. Therefore, if the average received power ratio between two sectors in the mobile communication terminal 10 is obtained, the direction of the mobile communication terminal 10 from the cellular base station 20 and the two sectors adjacent to the cellular base station shown in FIG. The direction of the mobile communication terminal 10 can be estimated using the relationship between the antenna gain of the radio communication terminal 10 and the antenna gain.

  In order to obtain the above average received power ratio, it is usually necessary to measure the average received power of each sector in the cellular base station 20. In the present invention, in order to perform measurement easily, it is desirable to estimate the average received power ratio between two sectors using the reception state of a plurality of radio waves without measuring the average received power. If the terminal has a DHO function, the sector ID of each sector obtained from the DHO information may be used.

  Radio signals are reflected, scattered, and diffracted by obstacles on the propagation path, and signal power varies stochastically on the time axis as shown in the signal fluctuation image shown in the graph of FIG. 5 (fading). ). In the graph of FIG. 5, the horizontal axis is the time axis, the vertical axis is the signal power, and the average signal power indicates two signals (radio waves) a and b (average signal power is , Indicated by a straight line in the graph of FIG. Consider a case in which signals from two sectors are received and a signal with high power is selected as a received signal. When a signal undergoes fading, each reception probability (selection probability) is determined by the nature of fading and the respective average signal power. If the signal reception probability is obtained by the property, the average power ratio can be estimated from the fading property.

ここで、ｄは直接波の振幅、Ｉ_０は第１種０次ベッセル関数、ｄ^２／２σ^２はフェージングのライス係数Ｋである。そして、その包絡線の確率分布関数Ｐ（Ｖ）は以下の式となる。

ここで、Ｖは信号振幅、Ｄは直接波の振幅、Ｉ_ｋ（ｋ＝０〜∞）は第１種ｋ次ベッセル関数、Γ（ｘ）はガンマ関数である。 When the signal having the average power σ ² is fading, the probability density function p (v) at which the signal amplitude is v is expressed by the following equation.

Here, d is the amplitude of the direct wave, I ₀ is the first kind 0th-order Bessel function, and d ² / 2σ ² is the fading Rice coefficient K. And the probability distribution function P (V) of the envelope is as follows.

Here, V is the signal amplitude, D is the amplitude of the direct wave, I _k (k = 0 to ∞) is the first kind k-order Bessel function, and Γ (x) is the gamma function.

ここで、Ｐ_ａ（Ｖ），Ｐ_ｂ（Ｖ）は、それぞれ信号ａ，ｂの確率分布関数Ｐ（Ｖ）である。 When there are signals a and b whose average powers are σ ² and rσ ² (r is the average power ratio of signal a to signal b), respectively, and when fading of the same property is independently received, the amplitude of signal b The probability distribution function that becomes larger than the signal a is as follows.

Here, P _a (V) and P _b (V) are probability distribution functions P (V) of the signals a and b, respectively.

  The probability distribution function can be regarded as a function of the average power ratio r of the signals a and b and the Rice coefficient. That is, the probability that the signal a is received (the probability that the signal a is selected because the received power of the signal a exceeds the received power of the signal b) is determined from the average power ratio of the two signals and the nature of fading. If the inverse function of the above function is obtained, the average power ratio of the signal can be obtained from the reception probability of the signal a and the nature of fading.

  When it is difficult to obtain an inverse function, the relationship between the average power ratio and the reception probability may be obtained using computer simulation. The graph of FIG. 6 shows the relationship between the reception probability of the signal a (probability of a> b), the fading property (Rice coefficient), and the average power ratio of the signals a and b, obtained by computer simulation. From the reception probability of the signal a, it is possible to estimate the average received power ratio of a and b (ratio of the average received power of the signal a to the average received power of the signal b). From the estimated average received power ratio, the direction of the mobile communication terminal 10 can be estimated based on the relationship between the direction shown in the graph of FIG. 4 and the antenna gains of the two sectors. In the following description, a sector related to the signal a having a high reception probability is called a main sector, and a sector related to the signal b having a low reception probability is called a sub-sector. The above is the principle of direction estimation according to the present invention.

  Subsequently, the function of the mobile communication terminal 10 that estimates the direction of the terminal 10 based on the above principle will be described. As shown in FIG. 1, the mobile communication terminal 10 includes a communication unit 11, a storage unit 12, a reception information acquisition unit 13, a direction estimation unit 14, and an accuracy estimation unit 15. In addition to the above configuration, the mobile communication terminal 10 includes components that are generally included in the mobile communication terminal 10 (not shown).

  The communication unit 11 is means for performing mobile communication. As one of the functions for performing mobile communication, the communication unit 11 performs radio communication by transmitting and receiving radio waves to and from the cellular base station 20. The communication unit 11 receives radio waves for estimating the direction using the function. The reception of the radio wave is preferably performed a plurality of times at regular intervals, for example. When reception of the radio wave is performed a plurality of times, it is desirable that the interval be performed at an interval equal to or longer than the fading fluctuation period. The number of times radio waves are received and the reception interval (measurement interval) are preset as tuning parameters and are stored in the communication unit 11.

  The mobile communication terminal 10 can receive radio waves of cells and sectors as described above. The communication unit 11 treats a radio wave having the highest received power among a plurality of received radio waves as a received radio wave (observed radio wave) for direction estimation. Alternatively, the communication unit 11 may treat all of a plurality of received radio waves (or all radio waves that have received power above a certain level) as received radio waves (observed radio waves) for direction estimation. Good. The communication unit 11 outputs information on the received radio waves (observed radio waves) to the reception information acquisition unit 13 as information indicating a reception state of radio waves from the cellular base station 20. The information output to the reception information acquisition unit 13 includes the cell ID of the cellular base station 20 from which the radio wave is transmitted and the sector ID of the sector.

  The storage unit 12 is a unit that stores information indicating a relationship based on radio wave directivity between a direction from the cellular base station 20 and a radio wave reception state of the mobile communication terminal 10 in the direction. Specifically, the directivity of radio waves corresponds to the antenna pattern described above. The information indicating the relationship is information used for estimating the direction of the mobile communication terminal 10 based on the principle described above. The storage unit 12 stores the above relationship according to radio waves in two transmission directions (two sectors) according to the principle described above. Specifically, first, the storage unit 12 stores the probability of reception of radio waves in two sectors at the mobile communication terminal 10 and the average (reception) power ratio of radio waves in the two sectors as shown in the graph of FIG. It holds information indicating the relationship. This information is information for calculating the above average power ratio from the above reception probability. This information can be obtained, for example, by computer simulation as described above. Further, the information indicating the above relationship is in accordance with the fading property and is stored for each rice coefficient K indicating the fading property.

  The storage unit 12 also has an antenna gain ratio of radio waves of two adjacent sectors and an angle (where the mobile communication terminal 10 is located) from the antenna direction (sector central direction) as shown in the graph of FIG. Holds information indicating the relationship between The graph of FIG. 7 shows the angle from the center of one sector (sector related to the radio wave a) to the adjacent sector (sector related to the radio wave b). The graph of FIG. 7 is a graph corresponding to a sector having a central angle of 60 °. This relationship can be calculated from the antenna pattern in each sector as shown in the graph of FIG. This information is information for calculating the direction of the terminal 10 from the above average power ratio.

  The reception information acquisition unit 13 is a reception information acquisition unit that acquires information indicating the reception state of the radio wave of the terminal 10 itself. As described above, the reception information acquisition unit 13 uses the cell ID of the cellular base station 20 and the sector ID of the sector related to the radio wave received (observed) by the communication unit 11 as information indicating the reception state. 11 is input. When the communication unit 11 receives a plurality of times of radio waves, the reception information acquisition unit 13 acquires information indicating the reception state of the radio waves of the terminal 10 a plurality of times.

  Based on the information input from the communication unit 11, the reception information acquisition unit 13 generates information on the number of receptions (number of observations) of radio waves for each sector ID as illustrated in FIG. The reception information acquisition unit 13 generates information illustrated in FIG. 8A by selecting information for each radio wave of two adjacent sectors of the specific cellular base station 20 from the information input from the communication unit 11. To do. The specific cellular base station 20 is the cellular base station 20 that is a base point for estimating the direction of the terminal 10 itself. When information related to signals from a plurality of cellular base stations 20 is included in the information input from the communication unit 11, for example, information on the cellular base station 20 having the largest number of information is selected.

  Further, when information related to signals of three or more sectors is included, the reception information acquisition unit 13 specifies radio waves of two sectors used for direction estimation based on the reception state. Specifically, for example, the reception information acquisition unit 13 sets the sector with the largest number of observations as the main sector, and sets the sector with the larger number of observations as the sub-sector from the adjacent sectors on both sides. Alternatively, the RTT may be measured from the received radio wave, and the sector with the smallest measured RTT value may be used as the main sector, and the sector with the smallest RTT value from the adjacent sectors may be used as the sub-sector. Alternatively, the sector having the smallest measured RTT value may be set as the main sector, and the sector having the larger number of observations from the sectors adjacent to the sector may be set as the sub sector. The sector with the highest number of observations may be set as the main sector, and the sector with the smaller RTT value from the adjacent sectors may be set as the sub-sector. The reception information acquisition unit 13 stores information indicating the adjacent relationship between sectors in advance, and performs the above selection of sectors related to radio waves used for direction estimation based on the information. Moreover, when specifying the sector using RTT as mentioned above, the mobile communication terminal 10 (the communication part 11 and the received information acquisition part 13) has a function which measures RTT.

  The reception information acquisition unit 13 generates the radio wave observation probability for each sector ID shown in FIG. 8B from the generated information on the number of times radio waves are received for each sector ID as shown in FIG. Reception probability). The observation probability is determined by dividing the number of radio wave observations for each sector ID by the sum of the number of radio wave observations for each sector ID.

  The reception information acquisition unit 13 calculates the ratio of the radio wave reception intensity of the two sectors of the terminal 10 from the calculated observation probability. The ratio of the reception intensity is the above-described average (reception) power ratio of the radio waves of the two sectors. The reception information acquisition unit 13 stores the reception probability of the radio waves of the two sectors stored in the storage unit 12 in the mobile communication terminal 10 shown in the graph of FIG. 6 and the average (reception) power ratio of the radio waves of the two sectors. The average power ratio is calculated with reference to the information indicating the relationship. Here, the reception information acquisition unit 13 sets a sector having a high observation probability as the main sector of the terminal 10 itself. That is, the reception information acquisition unit 13 uses the radio wave of the sector with the higher observation probability as the radio wave a in the graph of FIG. 6 (the radio wave of the sector with the lower observation probability as the radio wave b in the graph of FIG. 6), and average power Calculate the ratio. In the example of FIG. 8B, direction estimation is performed using the sector with the sector ID “4” as the main sector.

  When calculating the above average power ratio, the reception information acquisition unit 13 sets a Rice coefficient and uses a relationship according to the Rice coefficient. The set rice coefficient may be input in advance by a user or the like according to the mobile communication network, for example. For example, when the Rice coefficient is set to 0 (Rayleigh fading), in the example of FIG. 8B, the signal average power ratio between the sector with sector ID “4” and the sector with sector ID “3” is about 5 .5 dB. Further, the signal average power ratio of the sector with sector ID “4” and the sector with sector ID “3” is 5.5 dB based on the idea that the average reception power ratio and the antenna gain ratio are the same.

  For the above-described setting of the rice coefficient, a unique value tuned in advance for each cellular base station 20 (cell) may be used. In that case, the reception information acquisition unit 13 stores in advance information indicating the correspondence between the cell ID and the Rice coefficient related to the cellular base station 20. The reception information acquisition unit 13 sets a rice coefficient from the cell ID included in the signal received by the communication unit 11 based on the information indicating the correspondence relationship.

  Also, the Rice coefficient may be set for each propagation environment such as A in the city, B in the suburbs, and C in the suburbs. In that case, for example, information indicating the correspondence between the propagation environment and the Rice coefficient is stored in advance. The reception information acquisition unit 13 stores information indicating the correspondence relationship between the cell ID and the propagation environment in advance, and information indicating the above correspondence relationship from the cell ID included in the signal received by the communication unit 11. The propagation environment and the rice coefficient are set based on The Rice coefficient may be a unified value for all cellular base stations 20 (cells). Other methods may be used.

  The reception information acquisition unit 13 outputs the calculated average power ratio information to the direction estimation unit 14. Note that the calculation of the average power ratio does not necessarily use the relationship of the graph of FIG. 6. The above-described equation is stored in the reception information acquisition unit 13 in advance, and mathematically (a priori) by the equation. It may be derived.

  Further, the relationship used by the reception information acquisition unit 13 for calculating the average power ratio may not be obtained by the computer simulation as shown in FIG. 6, for example, linear approximation as shown in FIG. (In this case, the storage unit 12 stores a linear approximation relationship). In this case, the estimation direction can be easily calculated, but the accuracy of the direction estimation may deteriorate. Here, the function used for the linear approximation may be calculated based on the maximum value (average power ratio when the reception probability is 100%) specified by tuning. This function is such that the average power ratio is 1 when the reception probability is 50%. As a tuning method, for example, a function (relationship between reception probability and average power ratio) calculated using a plurality of maximum values is prepared, and the direction estimation accuracy is the best.

  The direction estimation unit 14 is a direction estimation unit that estimates the direction of the terminal 10 from the information input from the reception information acquisition unit 13 based on the information stored in the storage unit 12. Specifically, the direction of the terminal 10 is calculated from the average power ratio information input from the reception information acquisition unit 13. The direction estimation unit 14 refers to the relationship between the antenna gain ratio of the radio waves of the two adjacent sectors shown in FIG. 7 and the angle at which the mobile communication terminal 10 is located from the antenna direction, stored in the storage unit 12. Then, the direction of the own terminal 10 is calculated. The direction of the own terminal 10 calculated here is an angle from the center of the sector which is the main sector in the reception information acquisition unit 13 to the other sector direction.

  In the example shown in FIG. 8 (when the signal average power ratio between the sector with sector ID “4” and the sector with sector ID “3” is 5.5 dB), the gain ratio corresponds to 5.5 dB as shown in FIG. Since the angle corresponds to a direction of about 18 °, the direction estimation unit 14 determines that the terminal 10 is in the direction of 18 ° from the center direction of the sector with the sector ID “4” to the sector with the sector ID “3”. calculate. The direction estimation unit 14 outputs information indicating the calculated direction as information on the estimation result. This output may be performed, for example, on a means for estimating the position of the own terminal 10 further provided in the mobile communication terminal 10 or displayed on the display of the own terminal 10 so that it can be referred to by the user. May be performed.

  Although the graph of FIG. 7 is a graph corresponding to a sector having a central angle of 60 °, different information may be used for each sector angle. When the sector angle differs for each cellular base station 20, the direction estimation unit 14 can specify the angle from the cell ID, for example, and the mobile communication from the antenna gain ratio and the antenna direction according to the sector angle. The relationship with the angle at which the terminal 10 is located is used.

  Further, the relationship used by the direction estimation unit 14 to calculate the direction may not be obtained from the antenna patterns of the two sectors as shown in FIG. 7, for example, a linear approximation as shown in FIG. (In this case, the storage unit 12 stores a linearly approximated relationship). In this case, the estimation direction can be easily calculated, but the accuracy of the direction estimation may deteriorate. Here, the function used for the linear approximation may be a linear function with the antenna front-back ratio as the maximum value (the antenna gain ratio when the angle from the antenna direction is 0). This function is such that the antenna gain ratio is 1 when the angle of the antenna is the central direction of two sector directions (30 ° in the case of FIG. 10). In addition, the function used for linear approximation may determine the maximum value by tuning. As a tuning method, for example, a function (relation between an angle from the antenna direction and the gain ratio of the antenna) calculated using a plurality of maximum values is prepared, and the direction estimation accuracy is the best.

  In the above description, the two sectors are adjacent cells. However, when there is no information related to the adjacent sector to the information input from the communication unit 11, the direction is determined by the above-described method using the two sectors having the smallest interval. It may be estimated. In this case, the relationship between the antenna gain ratio of the radio waves of two adjacent sectors and the angle from the antenna direction (where the mobile communication terminal 10 is located) shown in the graph of FIG. As the information to be shown, information considering the interval between the two sectors is used (the relationship is calculated and stored in the storage unit 12 in advance). In this case, the accuracy of direction estimation may deteriorate.

  The accuracy estimation unit 15 is an accuracy estimation unit that estimates the accuracy of the direction of the terminal 10 estimated by the direction estimation unit 14 from the information indicating the reception state of the radio wave in the terminal 10 acquired by the reception information acquisition unit 13. is there. In the direction estimation described above, the number of radio wave measurements (number of observations) and the number of DHO branches affect the accuracy of direction estimation. As an example, if the number of measurements (of radio waves in two sectors) is 10 and the number of DHO branches is 1, the resolution of the observation probability is 10%. In the above, since the direction of the mobile communication terminal 10 is estimated using a sector with a high observation probability as the main sector, the observation probabilities in the main sector are 6 patterns of 50%, 60%, 70%, 80%, 90%, and 100%. Become. Using the graph relationship when the Rice coefficient shown in FIG. 6 is 0 (Rayleigh fading), the signal average power ratio estimated from the observation probability is indicated by a circle in the graph of FIG. 11 except for the case of 100%. As shown in the figure, there are five patterns of about 1, 3, 5, 7, 9 times. Further, when the relationship between the antenna gain ratio and the angle from the antenna direction shown in FIG. 7 is used, the direction estimated from these signal average power ratios is as shown by the circled portion of the graph of FIG. 5 patterns of about 30 °, 22 °, 17 °, 14 ° and 12 °.

When the observation probability is 100%, the estimated direction is the center direction of the sector. Therefore, when the mobile communication terminal 10 is located between 0 ° and the estimated direction 12 ° when the observation probability is 90%, The corresponding error occurs. That is, in the direction estimation according to the present embodiment, as shown in FIG. 13, the angle range from the sector center direction to ± θ _max is a low accuracy region, and the angle range from ± θ _max to the end of the sector is a high accuracy region. It has the characteristic of becoming. Here, in FIG. 13, α is an angle from the center direction of the sector to the end of the sector, and θ _max is the sector direction in the estimated direction when the observation probability is next to 100% (corresponding to 90% in the above). Each angle is shown from the center direction. That is, even if the mobile communication terminal 10 is located in an angular range from the center direction of the sector to ± θ _max , the direction can be estimated only with low accuracy. The accuracy estimation unit 15 uses this feature to estimate the error included in the estimated direction as the estimated accuracy of the direction of the terminal 10 (the accuracy is high if the error is small).

First, the accuracy estimation unit 15 uses information on the number of pieces of information indicating the reception state of radio waves for estimating the direction from the reception information acquisition unit 13 (that is, the premise of estimation) as information indicating the reception state of radio waves at the terminal 10 itself. Alternatively, information as a condition) is acquired. This number is the sum of the numbers of information indicating the radio wave reception state measured each time when there are a plurality of DHO branches. Hereinafter, a case where the number of DHO branches is 1 will be described. When the number of measurements is n (n> 1), the resolution of the observation probability is 1 / n, and the accuracy estimation unit 15 determines the maximum observation probability P _max = (n−1) / excluding 100% from the number of measurements. n is calculated. The accuracy estimation unit 15 stores the relationship between the reception probability of the radio waves of the two sectors in the mobile communication terminal 10 and the average (reception) power ratio of the radio waves of the two sectors shown in the graph of FIG. referring to the information indicating the _calculated average power ratio _{R max} corresponding to _{P max.} Subsequently, the accuracy estimation unit 15 stores the relationship between the antenna gain ratio of the radio waves of the two adjacent sectors shown in FIG. 7 stored in the storage unit 12 and the angle at which the mobile communication terminal 10 is located from the antenna direction. see, it calculates the direction theta _max corresponding to average power ratio _{R max.}

となる。 Subsequently, as shown in FIG. 13, when the sector width is 2α and the sector direction is 0 °, the accuracy estimation unit 15 defines the high accuracy region in the estimation direction as A _h1 = {α, θ _max } and A _h2 = It can be calculated as {−α, −θ _max }. Accuracy estimator 15, an error theta _Eh of the estimated direction which belongs to the high-precision area A _h, as the direction of the accuracy of the terminal 10 estimated by the direction estimating section 14, by dividing the high accuracy region in half the number of measurements n Estimate (calculate) as a value. That means

It becomes.

Further, the accuracy estimation unit 15 can calculate the low accuracy region in the estimation direction as A _l = [− θ _max , θ _max ] including the sector center direction. The accuracy estimation unit 15 uses the error θ _El of the estimated direction of the low accuracy area A ₁ as the accuracy of the direction of the terminal 10 estimated by the direction estimation unit 14, and the maximum error is θ _max and the average error is the maximum error. The half is θ _max / 2. The accuracy estimation unit 15 may use the calculated A _h , A _l , θ _Eh , and θ _El as information indicating the accuracy of the direction of the terminal 10 itself, or indicate the accuracy by a predetermined function using these as variables. It is good also as information which calculates a value and shows the precision of the direction of self-terminal 10.

  The accuracy estimation unit 15 outputs information indicating the calculated accuracy of the direction of the terminal 10 estimated by the direction estimation unit 14. For example, the output is performed together with the output of the output result by the direction estimation unit 14 and may be performed by displaying the result on a display or the like. The accuracy estimation unit 15 does not have to be directly provided as a component of the mobile communication terminal 10 because it is not directly related to the direction estimation.

As a variation of the direction estimation error calculation method, A _h , A _l , θ _Eh , θ _El can be weighted, and the weight may be a tuning parameter for each cell and sector. The weight may be a unified value in all cells and sectors.

  Subsequently, FIG. 14 shows a hardware configuration of the mobile communication terminal 10 according to the present embodiment. As shown in FIG. 14, the mobile communication terminal 10 includes a CPU (Central Processing Unit) 101, a RAM (Random Access Memory) 102, a ROM (Read Only Memory) 203, an operation unit 104, a wireless communication unit 105, a display 106, and an antenna. It is configured by hardware such as 107. The functions described above are exhibited by the operation of these components. The above is the configuration of the mobile communication terminal 10.

  Subsequently, a direction estimation process (direction estimation method) executed by the mobile communication terminal 10 according to the present embodiment will be described using the flowchart of FIG. This process is started by using, for example, an operation to start the direction estimation process for the mobile communication terminal 10 to perform positioning of the terminal 10 by the user. Further, for example, it may be started by a trigger other than the above, such as the mobile communication terminal 10 receiving a direction estimation request from another device.

  First, in the mobile communication terminal 10, a radio wave is received from the cellular base station 20 by the communication unit 11 to estimate the direction, and the radio wave with the highest received power is the radio wave observed for the direction estimation. The The observation is performed multiple times. Information related to the observed radio wave is output from the communication unit 11 to the reception information acquisition unit 13 (S01, reception information acquisition step). Based on the information input from the communication unit 11, the reception information acquisition unit 13 aggregates the number of observations of each sector and generates information on the number of observations for each sector ID as shown in FIG. 8A (S02). Received information acquisition step). This information is information of two adjacent sectors of the same cellular base station 20 as described above. Subsequently, the reception information acquisition unit 13 calculates the reception probability of the radio wave for each sector ID shown in FIG. 8B from the information on the number of radio wave observations for each sector ID (S03, reception information acquisition step).

  On the other hand, the reception information acquisition unit 13 sets the Rice coefficient related to the relationship for obtaining the average power ratio of radio waves from the reception probability (S04, reception information acquisition step). Subsequently, the reception information acquisition unit 13 stores the radio wave reception probability at the mobile communication terminal 10 in the two sectors shown in the graph of FIG. 6 and the two reception probabilities stored in the storage unit 12 according to the set Rice coefficient. Information indicating the relationship with the average power ratio of the radio waves in the sector is referred to (S05, reception information acquisition step). Subsequently, the average power ratio of the radio waves of the two sectors is calculated from the reception probability of the radio waves by the reception information acquisition unit 13 based on the referenced relationship (S06, reception information acquisition step). Information indicating the calculated average power ratio is output from the reception information acquisition unit 13 to the direction estimation unit 14.

  Subsequently, the direction estimation unit 14 estimates the direction of the terminal 10 from the information indicating the average power ratio input from the reception information acquisition unit 13 (S07, direction estimation step). This estimation is performed with reference to the relationship between the antenna gain ratio of the radio waves of two adjacent sectors shown in FIG. 7 and the angle at which the mobile communication terminal 10 is located from the antenna direction, stored in the storage unit 12. It is. The calculated direction information is appropriately output. The accuracy of the direction estimated by the direction estimation unit 14 may be estimated by the accuracy estimation unit 15 together with the estimation of the direction (not shown, accuracy estimation step). The above is the direction estimation process executed by the mobile communication terminal 10 according to the present embodiment.

  As described above, according to the present embodiment, based on the relationship between the cellular base station 20 and the radio wave reception state of the mobile communication terminal 10 based on the directivity of the radio wave (the relationship shown in FIGS. 2, 4, 7, etc.). The direction of the mobile communication terminal 10 is estimated. Compared with the method of estimating the direction of the terminal 10 from the cellular base station 20 based on the radio wave, the ratio of the number of times the radio wave is measured as described in the background art section, and the like, It can be performed with high accuracy.

  Further, by performing estimation based on observation of radio waves a plurality of times as in the present embodiment, it is possible to estimate the direction with higher accuracy. However, the direction may be estimated from a single radio wave measurement using the relationship shown in FIG.

  Moreover, if direction estimation is performed using radio waves of two sectors from radio waves of a plurality of sectors (plurality) as in the cellular of the present embodiment, the direction can be estimated appropriately. Furthermore, if the information indicating the average power ratio (reception intensity ratio) is calculated based on the number of observations as in the present embodiment and the direction is estimated from the average power ratio, the direction is easily estimated. be able to. That is, it is not necessary to use the value of the reception intensity for reception of each radio wave for estimating the direction, and the direction can be estimated.

  Further, if the accuracy of the estimated direction is calculated as in the present embodiment, the estimated direction is appropriately used, for example, when the accuracy of the mobile communication terminal 10 is estimated only when high accuracy is obtained. Can be used for various purposes.

  In the present embodiment, the direction of the mobile communication terminal 10 is estimated using the cellular base station 20 of the mobile communication system. However, the mobile communication system may not necessarily be used, and any radio wave transmission may be performed. What is necessary is just to estimate the direction of the mobile communication terminal that receives the radio wave from the source.

  In the embodiment described above, the main body of direction estimation is the mobile communication terminal 10 that is also the target of direction estimation, but the main body of direction estimation is not necessarily the mobile communication terminal 10. For example, the direction estimation system according to the present embodiment may be a positioning server 30 as shown in FIG. The positioning server 30 is, for example, a device included in a mobile communication network, and is connected to (a plurality of) cellular base stations 20 and can communicate with the mobile communication terminal 40 via the cellular base station 20. . The positioning server 30 is a device that estimates the direction of the mobile communication terminal 40. The direction is estimated by the same method as described above. The estimation of the direction is performed, for example, for the positioning server 30 to estimate the position of the mobile communication terminal 40 (positioning). The mobile communication terminal 40 that is the target of direction estimation has the same function as the mobile communication terminal 10 described above, but is configured to estimate the direction (storage unit 12, received information acquisition unit 13, direction estimation unit 14 and The accuracy estimation unit 15) may not be provided. In addition, the mobile communication terminal 40 transmits information necessary for the positioning server 30 to estimate the direction to the positioning server 30. The cellular base station 20 has the same configuration as that of the cellular base station 20 described above.

  As illustrated in FIG. 16, the positioning server 30 includes a transmission / reception unit 31, a storage unit 32, a reception information acquisition unit 33, a direction estimation unit 34, and an accuracy estimation unit 35.

  The transmission / reception unit 31 is means for transmitting / receiving information to / from the mobile communication terminal 40. The transmission / reception unit 31 outputs the information received from the mobile communication terminal 40 to the reception information acquisition unit 33. Information received by the transmission / reception unit 31 from the mobile communication terminal 40 (information transmitted from the mobile communication terminal 40 to the positioning server 30) is information output from the communication unit 11 to the reception information acquisition unit 13 in the mobile communication terminal 10 described above. Similar information. The transmission of the information from the mobile communication terminal 40 may be performed by a trigger on the mobile communication terminal 40 side, or the transmission / reception unit 31 transmits a signal for starting direction estimation to the mobile communication terminal 40. Accordingly, the above information may be transmitted from the mobile communication terminal 40 accordingly.

  The storage unit 32 has the same configuration as the storage unit 12 of the mobile communication terminal 10 described above. The reception information acquisition unit 33 has the same configuration as the reception information acquisition unit 13 of the mobile communication terminal 10 described above except that the input of information is the transmission / reception unit 31. The direction estimation unit 34 and the accuracy estimation unit 35 have the same configurations as the direction estimation unit 14 and the accuracy estimation unit 15 of the mobile communication terminal 10 described above, respectively. The positioning server 30 also includes means for estimating the position of the mobile communication terminal 40 from the direction estimated by the accuracy estimation unit 15 (not shown).

  FIG. 17 shows a hardware configuration of the positioning server 30. As shown in FIG. 17, the positioning server 30 includes a computer including a CPU 301, a RAM 302 and a ROM 303 as main storage devices, a communication module 304 for performing communication, and an auxiliary storage device 305 such as a hard disk. Composed. The functions of the positioning server 30 described above are exhibited when these components are operated by a program or the like.

  The processing is also performed in the same manner as the processing in the mobile communication terminal 10 described above. However, the acquisition of information by the reception information acquisition unit 33 is performed when the information is transmitted from the mobile communication terminal 40 and received by the transmission / reception unit 31 and is input from the transmission / reception unit 31 to the reception information acquisition unit 33. Is called. As described above, the direction estimation system according to the present embodiment may be configured by an apparatus different from the mobile communication terminal 40 that is also a target of direction estimation.

  Subsequently, a direction estimation program for causing a computer (provided in the mobile communication terminal 10 or the positioning server 30) to perform the above-described series of processing for estimating the direction of the mobile communication terminal 10 will be described. As shown in FIG. 18, the direction estimation program 51 is stored in a program storage area 50a formed in a recording medium 50 provided in the computer.

  The direction estimation program 51 includes a main module 51a that centrally controls the direction estimation processing, a communication module 51b, a storage module 51c, a received information acquisition module 51d, a direction estimation module 51e, and an accuracy estimation module 51f. Configured. Functions realized by executing the communication module 51b, the storage module 51c, the reception information acquisition module 51d, the direction estimation module 51e, and the accuracy estimation module 51f are the communication unit 11, the storage unit 12, and the reception of the mobile communication terminal 10 described above. The functions of the information acquisition unit 13, the direction estimation unit 14, and the accuracy estimation unit 15 are the same.

  The direction estimation program 51 may be configured such that part or all of the direction estimation program 51 is transmitted via a transmission medium such as a communication line, and is received and recorded (including installation) by another device.

It is a figure which shows the function structure of the mobile communication terminal which is a direction estimation system which concerns on embodiment of this invention. It is a graph which shows the relationship (antenna pattern) of the direction from a cellular base station, and the antenna gain in the mobile communication terminal according to the said direction. It is a figure which shows the direction of the mobile communication terminal from two sectors and a cellular base station of a cellular base station. It is a graph which shows the relationship between the direction of the mobile communication terminal from a cellular base station, and the antenna gain in the mobile communication terminal of the electromagnetic wave from two sectors of a cellular base station. It is a graph which shows the change of the reception power in a mobile communication terminal according to time. It is a graph which shows the relationship between average power ratio and reception probability. It is a graph which shows the relationship between the gain ratio of the antenna of the radio wave of two adjacent sectors, and the angle at which the mobile communication terminal is located from the antenna direction (center direction of the sector). This is information indicating the number of observations of radio waves for each sector acquired by the reception information acquisition unit and the observation probability. It is a graph which shows the relationship which carried out the linear approximation of average power ratio and reception probability. It is a graph which shows the linear approximation relationship of the gain ratio of the antenna of the radio wave of two adjacent sectors, and the angle which a mobile communication terminal is located from an antenna direction (sector center direction). It is the graph which showed the average power ratio which can be calculated as an estimated value when the frequency | count of a measurement is 10. It is the graph which showed the angle of the mobile communication terminal from the antenna direction which can be calculated as an estimated value when the frequency | count of a measurement is 10. It is a figure which shows the low precision range of the direction estimation in a sector in this embodiment. It is a figure which shows the hardware constitutions of the mobile communication terminal which concerns on embodiment of this invention. It is a flowchart which shows the process (direction estimation method) performed with the mobile communication terminal which concerns on embodiment of this invention. It is a figure which shows the function structure of the positioning server which is a direction estimation system which concerns on embodiment of this invention. It is a figure which shows the hardware constitutions of the positioning server which concerns on embodiment of this invention. It is a figure which shows the structure of the direction estimation program which concerns on embodiment of this invention. It is a figure for demonstrating the estimation of the method of the conventional mobile communication terminal.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Mobile communication terminal, 11 ... Communication part, 12 ... Memory | storage part, 13 ... Received information acquisition part, 14 ... Direction estimation part, 15 ... Accuracy estimation part, 101 ... CPU, 102 ... RAM, 103 ... ROM, 104 ... Operation , 105 ... wireless communication unit, 106 ... display, 107 ... antenna, 20 ... cellular base station, 30 ... positioning server, 31 ... transmission / reception unit, 32 ... storage unit, 33 ... received information acquisition unit, 34 ... direction estimation unit, 35: Accuracy estimation unit 301: CPU 302: RAM 303 ... ROM 304 Communication module 305 Auxiliary storage device 40 Mobile communication terminal 50 Recording medium 50a Program storage area 51 Direction estimation Program, 51a ... main module, 51b ... communication module, 51c ... storage module, 51d ... received information acquisition module, 51e ... direction estimation module Lumpur, 51f ... accuracy estimation module.

Claims (10)

A direction estimation system that estimates the direction of a mobile communication terminal from a radio wave source,
A storage unit storing information indicating a relationship based on the directivity of the radio wave between the direction from the transmission source and the radio wave reception state of the mobile communication terminal in the direction;
Reception information acquisition means for acquiring information indicating a reception state of the radio wave of the mobile communication terminal;
Direction estimation means for estimating the direction based on information indicating the relationship stored in the storage unit from information indicating the reception state of the radio wave acquired by the reception information acquisition means;
With
The transmission source transmits radio waves in two transmission directions,
The storage unit stores information indicating a relationship between an angle with respect to the two transmission directions and a ratio of reception intensity of radio waves in the two transmission directions as information indicating a relationship based on directivity of the radio waves,
The reception information acquisition means stores in advance information indicating the relationship between the ratio of the number of receptions of radio waves in the two transmission directions based on the nature of radio wave fading and the ratio of the reception intensity of radio waves in the two transmission directions. In addition, the mobile communication terminal acquires information indicating the number of receptions of the radio waves in the two transmission directions, based on the relationship from the ratio of the reception frequency of the radio waves in the two transmission directions according to the acquired information. Calculate information indicating the ratio of the received strength of radio waves in the two outgoing directions,
The direction estimation unit is configured to determine the direction based on information indicating the relationship stored in the storage unit from information indicating a ratio of radio wave reception strengths of the two transmission directions acquired by the reception information acquisition unit. to estimate, direction estimation system.   The reception information acquisition unit stores in advance information indicating a relationship between a ratio of the number of receptions of radio waves in the two transmission directions and a ratio of reception strengths of the radio waves in the two transmission directions, which are different in fading nature. The direction estimation system according to claim 1, wherein information corresponding to the transmission source among the plurality of pieces of information is used for calculation of information indicating a ratio of radio wave reception intensity in the two transmission directions. From the information indicating the reception state of the radio wave acquired by the reception information acquisition means, the relationship between the angle with respect to the two transmission directions stored in the storage unit and the ratio of the reception intensity of the radio waves in the two transmission directions based on the information indicating, direction estimation system according to claim 1 or 2 further comprising a precision estimating means for estimating the direction of the accuracy estimated by the direction estimation means. The transmission source transmits radio waves in three or more transmission directions,
The reception information acquisition means acquires information indicating a reception state for each radio wave in the three or more transmission directions of the mobile communication terminal, and uses the two transmissions to estimate the direction based on the reception state Identify the direction of the radio waves,
The direction estimation system according to any one of claims 1 to 3 . Information indicating a direction based on the directivity of the radio wave between the direction from the source and the reception state of the radio wave of the mobile communication terminal in the direction is estimated from the direction of the mobile communication terminal from the radio wave source. A direction estimation method by a direction estimation system including a stored storage unit,
A reception information acquisition step of acquiring information indicating a reception state of the radio wave of the mobile communication terminal;
A direction estimating step for estimating the direction based on information indicating the relationship stored in the storage unit from information indicating the reception state of the radio wave acquired in the reception information acquiring step;
Only including,
The transmission source transmits radio waves in two transmission directions,
The storage unit stores information indicating a relationship between an angle with respect to the two transmission directions and a ratio of reception intensity of radio waves in the two transmission directions as information indicating a relationship based on directivity of the radio waves,
In the reception information acquisition step, the mobile communication terminal acquires information indicating the number of receptions of the radio waves in the two transmission directions, and the ratio of the reception frequency of the radio waves in the two transmission directions according to the acquired information From the relationship between the ratio of the number of receptions of radio waves in the two transmission directions based on the characteristics of radio wave fading stored in advance and the ratio of the reception strengths of the radio waves in the two transmission directions, Calculate information indicating the ratio of received strength,
In the direction estimation step, the direction is determined based on information indicating the relationship stored in the storage unit from information indicating a ratio of radio wave reception strengths in the two transmission directions acquired in the reception information acquisition step. to estimate, direction estimation method.   In the reception information acquisition step, a plurality of information indicating a relationship between a ratio of the number of receptions of radio waves in the two transmission directions and a ratio of reception strengths of the radio waves in the two transmission directions, which are different in pre-stored fading characteristics The direction estimation method according to claim 5, wherein information corresponding to the transmission source is used for calculation of information indicating a ratio of radio wave reception intensity in the two transmission directions. From the information indicating the reception state of the radio wave acquired in the reception information acquisition step, the relationship between the angle with respect to the two transmission directions stored in the storage unit and the ratio of the reception intensity of the radio waves in the two transmission directions is The direction estimation method according to claim 5 or 6 , further comprising an accuracy estimation step of estimating the accuracy of the direction estimated in the direction estimation step based on information to be indicated. The transmission source transmits radio waves in three or more transmission directions,
In the reception information acquisition step, the mobile communication terminal acquires information indicating reception states for each radio wave in the three or more transmission directions, and uses the two transmissions for estimation of the direction based on the reception states. Identify the direction of the radio waves,
The direction estimation method according to claim 5 , wherein the direction is estimated. A direction estimation program that causes a computer to estimate the direction of a mobile communication terminal from a radio wave source,
A storage function that stores information indicating a relationship based on the directivity of the radio wave between the direction from the transmission source and the radio wave reception state of the mobile communication terminal in the direction;
A reception information acquisition function for acquiring information indicating a reception state of the radio wave of the mobile communication terminal;
A direction estimation function for estimating the direction based on information indicating the relationship stored by the storage function from information indicating a reception state of the radio wave acquired by the reception information acquisition function;
To the computer ,
The transmission source transmits radio waves in two transmission directions,
The storage function stores information indicating a relationship between an angle with respect to the two transmission directions and a ratio of reception intensity of radio waves in the two transmission directions as information indicating a relationship based on directivity of the radio waves,
The reception information acquisition function stores in advance information indicating the relationship between the ratio of the number of receptions of radio waves in the two transmission directions based on the nature of radio wave fading and the ratio of the reception intensity of radio waves in the two transmission directions. In addition, the mobile communication terminal acquires information indicating the number of receptions of the radio waves in the two transmission directions, based on the relationship from the ratio of the reception frequency of the radio waves in the two transmission directions according to the acquired information. Calculate information indicating the ratio of the received strength of radio waves in the two outgoing directions,
The direction estimation function determines the direction based on information indicating the relationship stored in the storage function from information indicating a ratio of radio wave reception strengths of the two transmission directions acquired by the reception information acquisition function. estimated to, the direction estimation program.   The reception information acquisition function stores in advance information indicating a relationship between a ratio of the number of receptions of radio waves in the two transmission directions and a ratio of reception strengths of the radio waves in the two transmission directions, which have different fading characteristics. The direction estimation program according to claim 9, wherein information corresponding to the transmission source among the plurality of pieces of information is used for calculation of information indicating a ratio of reception intensity of radio waves in the two transmission directions.

Images