JP2010043996A - Terminal location estimation system and method, and position estimation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the location estimation precision of a terminal in estimating a terminal location from an incoming-direction estimation straight calculated based on a wireless communication signal between the terminal and a wireless base station. <P>SOLUTION: A terminal location estimation system includes: received-power calculation parts A1 to AN for measuring received power of signals received by a plurality of antennas; incoming-direction estimation parts B1 to BN for estimating the incoming direction of an electric wave from the received signal; and a weighing terminal location estimation part C for calculating the incoming-direction estimation straight from the estimated incoming direction and a coordinate of a communicating base station for the electric wave and for estimating a terminal location by executing weighing for further increasing weighing as the received power is higher, based on the incoming-direction estimation straight of the respective base stations and the respective received power. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a terminal position estimation system and method and a position estimation apparatus that estimate the position of a terminal by estimating the arrival direction of radio waves between a wireless terminal and a plurality of base stations.

FIG. 5 is a block diagram showing a configuration of a wireless device (terminal position estimation system) according to the technology that is the background of the present invention. In the terminal position estimation method by the wireless device shown in this figure, in a wireless device equipped with a plurality of wireless base stations S0-1 to S0-N and one or a plurality of terminals T0, radio waves between the terminal and the plurality of wireless base stations are transmitted. By estimating the arrival direction, the position of the terminal is estimated.
In this case, the radio base station S0-1~S0-N, a plurality of antennas _{# 1 1, # 2 1,} ..., # M 1 ~ # 1 N, # 2 N, ..., # M N and the radio unit R1 To RN and arrival direction estimation units B1 to BN. Each of the radio base stations S0-1 to S0-N estimates the arrival direction of the radio waves by the arrival direction estimation units B1 to BN, and the arrival direction estimation straight line from the coordinates of each of the radio base stations S0-1 to S0-N. L _{1 to} L _N are determined, and the terminal position estimation unit D obtains the position of the terminal T 0 from the arrival direction estimation straight lines L _{1 to} L _N. Specifically, each of the radio base station S0-1 if the radio base station is two, and the terminal position coordinates of the arrival direction estimation linear L _1, L ₂ of the intersection point P ₁₂ calculated in S0-2. When there are three or more radio base stations, since there are a plurality of intersections P ₁₂ , P ₁₃ , P ₂₃ ,..., P _NM of the respective arrival direction estimation straight lines L _{1 to} L _N , the intersections are geometrically averaged. These coordinates are set as the terminal position (see, for example, Non-Patent Document 1). Alternatively, the equations of the direction-of-arrival estimation straight lines are normalized, and the solution obtained by the pseudo inverse matrix calculation is set as the terminal position (see, for example, Non-Patent Document 2 (particularly Chapter 8)).
Jun Terada, Takahashi, H. Sato, Y. Mutoh, S. “A novel location-estimation method using direction-of-arrival estimation,” Vehicular Technology Conference, 2005. VTC-2005-Fall. 2005 IEEE 62nd, 28-25 Sept., 2005 Volume: 1, On page (s): 424-428 Ben Noble, James W. Danie “Applied Linear Algebra,” Prentice Hall; 3 edition (November 11, 1987)

  However, in the conventional techniques as shown in Non-Patent Documents 1 and 2 described above, the power of the radio signal transmitted from the terminal is greatly attenuated in a radio propagation environment, particularly in a place far away from the radio base station. As a result, the influence of noise increases and the estimation error of the arrival direction of the radio signal increases. Therefore, in such an environment, the reliability of the direction-of-arrival estimation line calculated by each radio base station is different, and when estimating the terminal position from each direction-of-arrival estimation line, the direction-of-arrival estimation with low reliability is performed. Positioning accuracy deteriorates due to the influence of straight lines. This phenomenon has a problem that it cannot be improved by the conventional technique for calculating the position of the terminal with the same reliability of all arrival direction estimation lines.

  In addition, since the accuracy of terminal position detection deteriorates, when performing position detection in a wireless system, the base station cannot increase the radio cell size, and a large number of base stations are required to cover a wide area.

  The present invention has been made in consideration of such circumstances, and its purpose is to estimate the terminal position from the arrival direction estimation line calculated based on the radio communication signal between the terminal and the radio base station. It is an object of the present invention to provide a terminal position estimation system and method and a position estimation apparatus that can improve the terminal position estimation accuracy.

  In order to solve the above-described problems, the present invention provides a terminal, three or more base stations that have a plurality of antennas and are installed at locations apart from each other, and the arrival direction of a radio signal between the terminal and the base station A terminal location estimation system comprising a location estimation device installed in any of the base stations or independently of the terminal and the base station, wherein the location of the terminal is estimated based on Receiving power measuring means for measuring the received power of the received signal from the terminal received at each of a plurality of antennas, and arrival direction estimating means for estimating the arrival direction of a radio wave from the received signal, the position The estimation device calculates the arrival direction estimation line for each base station from the arrival direction of the radio wave estimated by the arrival direction estimation means of the base station and the coordinates of the base station. Based on the arrival direction estimation straight line of each base station calculated by the constant straight line calculation means, the arrival direction estimation straight line calculation means, and the reception power measured by the reception power measurement means of each base station, the received power And a terminal position estimating means for estimating the position of the terminal by performing weighting to increase the weight as the value is higher.

  Further, the present invention provides the terminal location estimation system, wherein the base station includes the arrival direction estimation straight line calculation means instead of the location estimation device installed independently of the base station, and the arrival direction estimation The straight line calculation means calculates an arrival direction estimation straight line from the arrival direction estimated by the arrival direction estimation means of the own base station and the coordinates of the own base station.

  Further, the present invention comprises a terminal having a plurality of antennas and three or more base stations installed at locations distant from each other, and the terminal based on the arrival direction of the radio signal between the terminal and the base station In the terminal position estimation system for estimating the position of the received signal, the terminal comprises: received power measuring means for measuring received power of a received signal from each base station received by each of a plurality of antennas; and a received signal from each base station From the arrival direction estimation means for estimating the arrival direction of each radio wave, the arrival direction of each radio wave estimated by the arrival direction estimation means, and the coordinates of the base station of the transmission source of each radio wave, A direction-of-arrival estimation straight line calculating means to calculate, a direction-of-arrival estimation straight line of radio waves from each base station calculated by the direction-of-arrival estimation straight line calculating means, and a value measured by the received power measuring means. A terminal position estimation system for estimating the position of the terminal by weighting such that the higher the received power is, the higher the received power is based on the received power from the base station. It is.

  Also, the present invention provides the terminal location estimation system, wherein the terminal location estimation means uses an intersection calculation means for calculating an intersection of each of the two arrival direction estimation lines and a reception level measured by the reception power measurement means. Weight calculating means for estimating the terminal position by weighting the calculated intersection and averaging the weighted intersection positions by geometric load averaging.

  Further, according to the present invention, in the terminal location estimation system, the terminal location estimation unit weights the arrival direction estimation line equation using the reception level measured by the reception power measurement unit, The position of the terminal is estimated by performing a pseudo inverse matrix operation on a plurality of arrival direction estimation linear equations.

  In addition, the present invention provides a terminal, three or more base stations that have a plurality of antennas and are installed at locations apart from each other, and the terminal based on the arrival direction of the radio signal between the terminal and the base station A terminal location estimation method used in a terminal location estimation system comprising a location estimation device installed in any of the base stations or independently of the terminal and the base station, A received power measuring process in which a station measures received power of a received signal from the terminal received by each of a plurality of antennas; an arrival direction estimating process in which an arrival direction of a radio wave is estimated from the received signal; and the position estimating device Is a direction of arrival calculated from the direction of arrival of the radio wave estimated in the direction of arrival estimation of the base station and the coordinates of the base station. Based on a constant line calculation process, an arrival direction estimation line of each base station calculated in the arrival direction estimation line calculation process, and a reception power measured in the reception power measurement process of each base station, the received power And a terminal position estimation process for estimating the position of the terminal by weighting such that the higher the value is, the higher the weight is.

  Further, the present invention provides the terminal position estimation method, wherein the base station performs the arrival direction estimation straight line calculation process in the base station instead of the position estimation device installed independently of the base station, and the arrival direction. In the estimated line calculation process, the arrival direction estimation line is calculated from the arrival direction estimated in the arrival direction estimation process and the coordinates of the base station.

  Further, the present invention comprises a terminal having a plurality of antennas and three or more base stations installed at locations distant from each other, and the terminal based on the arrival direction of the radio signal between the terminal and the base station A terminal position estimation method in a terminal position estimation system that estimates the position of the received power measurement process in which the terminal measures received power of a received signal from each base station received by each of a plurality of antennas, and An arrival direction estimation process for estimating the arrival direction of each radio wave from the received signal from each base station, the arrival direction of each radio wave estimated in the arrival direction estimation process, and the coordinates of the base station of the transmission source of each radio wave A direction-of-arrival estimation straight line calculation process for calculating a direction-of-arrival estimation straight line, a direction-of-arrival estimation line of radio waves from each base station calculated in the direction of arrival estimation straight line calculation process, and the receiving power A terminal location estimation process for estimating a terminal position by performing weighting to increase the weight as the received power is higher based on the received power from the base station measured in the measurement process. This is a terminal position estimation method.

  Further, the present invention provides the terminal location estimation method, wherein the terminal location estimation process uses an intersection calculation process for calculating an intersection of each of the two arrival direction estimation lines and a reception level measured in the reception power measurement process. A weight calculation step of weighting the calculated intersection and estimating the position of the terminal by geometrically averaging the positions of the plurality of weighted intersections.

  Further, the present invention provides the terminal location estimation method, wherein in the terminal location estimation process, the arrival direction estimation line equation is weighted using the reception level measured in the reception power measurement process, and The position of the terminal is estimated by performing a pseudo inverse matrix operation on a plurality of arrival direction estimation linear equations.

  In addition, the present invention provides a terminal, three or more base stations that have a plurality of antennas and are installed at locations apart from each other, and the terminal based on the arrival direction of the radio signal between the terminal and the base station The position estimation apparatus in a terminal position estimation system comprising a position estimation apparatus installed in any of the base stations or independently of the terminal and the base station, wherein each of the base stations Arrival direction estimation line calculation means for calculating each arrival direction estimation line from the arrival direction of the radio wave estimated from the received signal from the terminal received by the base station at each of the plurality of antennas and the coordinates of the base station; Based on the direction-of-arrival estimation straight line of each base station and the received power of the received signal measured at each base station, a weight that increases the weight as the received power is higher A position estimating device characterized by comprising a terminal position estimating means for estimating the location of the terminal by performing.

  Further, the present invention provides the position estimation apparatus, wherein the base station includes the arrival direction estimation straight line calculation means instead of the position estimation apparatus installed independently of the base station, and the terminal position estimation means Is based on the arrival direction estimation straight line calculated from the arrival direction of the radio wave estimated by each base station and the coordinates of the base station, and the received power measured at each base station, the higher the received power, The position of the terminal is estimated by performing weighting to increase.

  Further, the present invention provides the position estimation apparatus, wherein the terminal position estimation unit uses an intersection calculation unit that calculates an intersection of each of the two arrival direction estimation lines, and a reception level measured by the reception power measurement unit. Weighting means for estimating the position of the terminal by weighting the calculated intersection and averaging the geometrical weights of the positions of the plurality of weighted intersections is provided.

  Further, the present invention provides the position estimation apparatus, wherein the terminal position estimation unit weights the arrival direction estimation line equation using the reception level measured by the reception power measurement unit, The position of the terminal is estimated by performing a pseudo inverse matrix operation on the arrival direction estimation linear equation.

  According to the present invention, in wireless communication between a terminal and a base station, a plurality of estimated directions of arrival are weighted based on received power measured by a plurality of antennas, and then the position of the terminal is estimated. The Therefore, it is possible to estimate the terminal position based on the reliability of each arrival direction estimation line, and it is possible to improve the terminal position estimation accuracy.

  According to the present invention, the intersection of the arrival direction estimation straight lines is weighted based on, for example, the average value, the maximum value, or the minimum value of the received power measured by the received power measuring means, and the positions of the plurality of intersection points are geometrically determined. Load average and determine terminal position. Therefore, it is possible to estimate the terminal position based on the reliability of each arrival direction estimation line, and it is possible to improve the terminal position estimation accuracy.

  Further, according to the present invention, the arrival direction estimation line equation is weighted based on the received power measured by the received power measuring means, a solution of the weighted equation is obtained by a pseudo inverse matrix operation, and the solution is obtained by the terminal. Determine with position. Therefore, it is possible to estimate the terminal position based on the reliability of each arrival direction estimation line, and it is possible to improve the terminal position estimation accuracy.

  Also, according to the present invention, it is possible to improve the position estimation accuracy of the terminal in the same cell size as compared to the one before application of the present invention. That is, even when the radio cell size is increased, it is possible to suppress a decrease in position estimation accuracy, and thus it is possible to increase the radio cell size, thereby reducing the number of base stations.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a wireless device (terminal position estimation system) according to the first embodiment of the present invention. The radio apparatus in FIG. 1 includes a plurality of radio base station apparatuses S1 to SN, a weighted terminal position estimation unit C connected to each radio base station apparatus S1 to SN via a predetermined communication line, and one or a plurality of radio terminals T0. (Only one unit is shown in FIG. 1). Note that the weighted position estimation unit C (position estimation apparatus) may be provided in any of the radio base station apparatuses S1 to SN or in the radio terminal, or an apparatus independent of the radio base station apparatus or the radio terminal. It may be installed inside.

In the figure, the radio base station apparatus S1~SN a plurality of receiving respective antennas _{# 1 1, # 2 1,} ..., # M 1 ~ # 1 N, # 2 N, ..., and # _{M N,} transmit and receive radio signals a radio portion R1~RN for, receiving antenna _{# 1 1, # 2 1,} ..., # M 1 ~ # 1 N, # 2 N, ..., received every # _{M N,} from the radio terminal T0 a reception power calculation unit A1~AN for calculating a reception power _W 1 to _W-N in each radio base station apparatus S1~SN for radio wave reception signal, a plurality of receiving antennas _{# 1 1, # 2 1,} ..., # M _{1 ~ # 1 N, # 2} N, ..., # arrival direction estimation unit B1~BN from a radio signal received by the radio unit R1~RN through _{M N} estimates the direction of arrival of radio waves from each radio terminal T0 Equipped with, and placed away from each other. The radio signal transmitted from the radio terminal T0 is received by each radio base station apparatus S1 to SN, and the arrival direction estimation unit B1 to BN calculates the arrival direction of the radio signal by a known method (described later). From the arrival direction calculated by the arrival direction estimation units B1 to BN and the coordinates of the radio base station apparatuses S1 to SN, the arrival direction estimation straight lines L _{1 to} L _N (a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = C ₂ ,..., A _N x + b _N y = c _N ), the equations L _{1 to} L _N of the arrival direction estimation line are calculated by the radio base station apparatuses S 1 to SN, respectively. Even after passing to the weighted terminal position estimating unit C, the calculated arrival direction information is transferred to the weighted terminal position estimating unit C, and the weighted terminal position estimating unit C calculates the equations for all the radio base station devices in a lump. Can be either. As will be described later, this weighted terminal position estimation unit C estimates the terminal position by performing weighting that increases the weight as the received power is higher, based on the received power.

In addition, the received signal power W from the wireless terminal T0 that is the measurement target in each of the radio base station apparatuses S1 to SN in the received power calculation units A1 to AN equipped in each of the radio base station apparatuses S1 to SN. _{1 to} W _N are calculated. The received power may be calculated using AGC (Automatic Gain Control) or the like in analog signal processing, or may be calculated using the moving average of the square component of a complex signal or the like in digital signal processing, and the received power is calculated. Any method is good. The received power calculation process may be performed as an RF (Radio Frequency) signal or a baseband signal.

The weighted terminal position estimation unit C of the present embodiment uses the arrival direction of radio waves calculated by the arrival direction estimation units B1 to BN based on the reception power calculated by the reception power calculation units A1 to AN. The terminal estimated position Z _est is calculated.

  Note that the arrival direction estimation methods in the arrival direction estimation units B1 to BN perform arrival direction estimation using a plurality of antennas such as CMA (Constant Modulus Algorithm), MMSE (Minimum Mean Square Error), and MUSIC (Multiple Signal Classification) method. Any method is conceivable.

  Here, a method of calculating the terminal position in the weighted terminal position estimation unit C will be described in detail.

(1) First Weighted Terminal Position Estimation Method As a first weighted terminal position estimation method by the weighted terminal position estimation unit C, for example, as shown in FIG. 2 (calculation method (1)), the arrival direction estimation straight line L ₁ and _{L 2} of the intersection _{P 12} on the received power _{W 1} and _{W 2} of the average value _{W ave12 = mean (W 1,} W 2) the weight of the receiving direction of arrival estimation linear _{L 2} and _{L 3} of the intersection point _{P 23} power W the weighted average value _{W 2} and _{W 3 ave23 = mean (W 2} , W 3), the arrival direction estimation linear _{L N-1} and _{L N} of intersection _{P (N-1)} and the received power _{W N-1} to _N the weighted average value _{W ave} of _{W N (N-1) N} = mean (W N-1, W N), and so on, continue to multiply the intersection coordinates, respectively, the positions of a plurality of intersections, mean ( W _ave12 P ₁₂ + W _ave23 P ₂₃ + ... + W _{av e (N-1) NP (N-1) N} ) and the geometrical load average, and the final terminal estimated position _Zest is determined.

In the example illustrated in FIG. 2, the weighted terminal position estimation unit C includes an intersection calculation unit C-1 and a weight multiplication unit C-2. This intersection calculation unit C-1 includes equations (simultaneous equations) a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ , from the arrival direction estimation units B1 to BN to the arrival direction estimation straight lines L _{1 to} L _N. .., A _N x + b _N y = c _N is received, and intersections P ₁₂ , P ₁₃ ,..., P _NM of the respective arrival direction estimation straight lines L _{1 to} L _N are calculated and output. Weight multiplier unit C-2 is received from the reception power calculation unit A1~AN power _W 1 to _W-N each intersection _P 12 calculated by the intersection calculation unit C-1 with receiving _information, P 13, _{..., P NM} For example, the terminal estimated position Z _est (estimated terminal position coordinates (x _est , y _est )) is calculated by the above-described method.

(2) Second Weighted Terminal Position Estimation Method As the second weighted terminal Sahara estimation method by the weighted terminal position estimation unit C, for example, as shown in FIG. 2 (calculation method (2)), the arrival direction estimation straight line L ₁ and receiving the intersection _{P 12} of _{L 2} power _{W 1} maximum value of the _{W 2 W max12 = max (W} 1, W 2) the weight of the receiving direction of arrival estimation linear _{L 2} and _{L 3} of the intersection point _{P 23} power W ₂ and the weight of the maximum value W _{max23 of} W ₃ = W max (W ₂ , W ₃ ) and the received power W _{N−1 at} the intersection P _{(N−1) N} of the arrival direction estimation lines L _N−1 and L _N. W _N maximum value _W max of the weights of _{(N-1) N = max} (W N-1, W N), and so on, continue to multiply the intersection coordinates, respectively, the positions of a plurality of intersections, mean ( _{W max12 P 12 + W max23 P} 23 + ... + W max (N _{-1) The} geometric load is averaged with _N P _{(N-1) N} ) to determine the final terminal estimated position Z _est .

(3) Third Weighted Terminal Position Estimation Method As the third weighted terminal position estimation method by the weighted terminal position estimation unit C, for example, as shown in FIG. 2 (calculation method (3)), the arrival direction estimation straight line L ₁ and receiving the intersection _{P 12} of _{L 2} power _{W 1} and a minimum value _W of _{W 2 min12 = min (W 1} , W 2) the weight of the receiving direction of arrival estimation linear _{L 2} and _{L 3} of the intersection point _{P 23} power W the weight of the minimum value _{W 2} and _{W 3 min23 = min (W 2} , W 3), the arrival direction estimation linear _{L N-1} and _{L N} of intersection _{P (N-1)} and the received power _{W N-1} to _N W _N minimum value _W min of the weight of _{(N-1) N = min} (W N-1, W N), and so on, continue to multiply the intersection coordinates, respectively, the positions of a plurality of intersections, mean ( W _min12 P ₁₂ + W _min23 P ₂₃ +... + W _{min (N -1) The} geometric load is averaged with _N P _{(N-1) N} ) to determine the final terminal estimated position Z _est .

  As described above (1) to (3), by weighting each intersection of each direction-of-arrival estimation line using the reception level, the distance from the radio base station apparatus having a low reception level, that is, the radio terminal can be reduced. A more accurate estimation of the terminal position is realized by lowering the weight of the intersection obtained from the base station which is considered to have a large error in the direction of arrival.

(4) Fourth Weighted Terminal Position Estimation Method As the fourth weighted terminal position estimation method by the weighted terminal position estimation unit C, for example, as shown in FIG. 3, arrival direction estimation straight lines L ₁ , L ₂ ,. _{A 1} x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ ,..., A _N x + b _N y = c _N , weight of received power amplitude | W ₁ | ˜ | W _N | do it,

Since AZ = C can be expressed, the pseudo inverse matrix of the determinant A is defined as A ^+, and A ⁺ is multiplied from the left side,

The obtained solution Z is defined as the final terminal estimated position Z _est .

FIG. 3 shows the weighted terminal position estimator C in FIG. 1 as a weighted terminal position estimator Ca. In this example, the weighted terminal position estimation unit Ca is composed of a weight multiplication unit Ca-3. The weight multiplication unit Ca-3 includes equations (simultaneous equations) a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ , from the arrival direction estimation units B 1 to BN to the arrival direction estimation lines L _{1 to} L _N. ..., a _N x + b _N y = c _N information is received, and received power information W _{1 to} W _N are received from the received power calculators A ₁ to AN, and a pseudo inverse matrix operation is performed as described above to obtain a solution. By calculating _| requiring, terminal estimated position _Zest (estimated terminal position coordinate ( _xest , _yest )) is calculated. That is, the weight multiplication unit Ca-3 performs weighting using the received power level measured for the equation of arrival direction estimation straight line, and performs a pseudo inverse matrix operation on the plurality of weighted arrival direction estimation linear equations after weighting. Thus, the position of the terminal is estimated.

(5) Fifth Weighted Terminal Position Estimation Method As a fifth weighted terminal position estimation method by the weighted terminal position estimation unit C, for example, as shown in FIG. 4, arrival direction estimation straight lines L ₁ , L ₂ ,. _N equation a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ ,..., A _N x + b _N y = c _N , received signal amplitude √ | W ₁ | ˜√ | W _N | Weight

Since AZ = C can be expressed, the pseudo inverse matrix of the determinant A is defined as A ^+, and A ⁺ is multiplied from the left side,

The obtained solution Z is defined as the final terminal estimated position Z _est .

FIG. 4 shows the weighted terminal position estimating unit C in FIG. 1 as a weighted terminal position estimating unit Cb. In this example, the weighted terminal position estimator Cb includes a weight multiplier Cb-3. The weight multiplication unit Cb-3 includes equations (simultaneous equations) a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ from the arrival direction estimation units B1 to BN and the arrival direction estimation lines L _{1 to} L _N. ..., a _N x + b _N y = c _N information is received, and received power information W _{1 to} W _N are received from the received power calculators A ₁ to AN, and a pseudo inverse matrix operation is performed as described above to obtain a solution. The terminal estimated position Z _est (estimated terminal position coordinates (x _est , y _est )) is calculated by _obtaining . That is, the weight multiplication unit Cb-3 performs weighting by using the received power level measured for the arrival direction estimation line equation, and performs a pseudo inverse matrix operation on the plurality of weighted arrival direction estimation line equations. Thus, the position of the terminal is estimated.

  As described in (4) and (5) above, the arrival direction estimation straight line itself is weighted using the reception level, so that the arrival direction estimation accuracy can be improved, and a highly accurate arrival direction straight line equation is used. Accurate estimation of the terminal position is realized by deriving the intersection.

  According to the first embodiment described above, it is possible to estimate the terminal position based on the reliability of each arrival direction estimation line, and it is possible to improve the terminal position estimation accuracy.

  In the embodiment, a method has been described in which a base station having a plurality of antennas receives a signal transmitted by a wireless terminal and estimates the position of the terminal from the reception level and the arrival direction. A wireless terminal having an antenna receives signals from a plurality of base stations, estimates reception levels and arrival directions, and notifies the weighted terminal position estimation unit of the present invention to estimate the terminal position. Also good. Hereinafter, such a configuration will be described as a second embodiment.

  6 and 7 are block diagrams showing the configuration of a radio apparatus according to the second embodiment of the present invention. FIG. 6 shows a radio apparatus comprising a radio terminal T and a plurality of radio base station apparatuses S0-1 to S0-N. FIG. 7 shows a part of the internal configuration of the wireless terminal T according to the present invention. Although only one unit is shown in FIG. 6, one or a plurality of wireless terminals T are provided.

6 and 7, respectively the radio terminal T plurality of receiving antennas _# 1 _T, # 2 T, ..., are equipped with # _{M T.} The radio signal transmitted from each radio base station apparatus (hereinafter also referred to as a base station) S0-1 to S0-N is received by the radio terminal T, and from which base station the base station discriminating unit I receives the radio signal. Then, the arrival direction estimation unit E calculates the arrival direction of the radio signal from each base station by a known method (described later). Here, as a method of identifying and separating which base station by the base station discriminating unit I, either by time division by changing the radio wave transmission time for each base station or by frequency division by changing the transmission frequency The space may be divided by the code, and any method for discriminating and separating the signal from the base station may be used.

Further, at the reception power calculation unit G that has been installed on the wireless terminal T, the antenna _{# 1 T, # 2 T,} ..., # M T received in each, each radio base station apparatus S0-1~S0-N The powers W _{1 to} W _N of the received signals from are calculated. The received power may be calculated using AGC or the like in analog signal processing, or may be calculated using a moving average of the square component of a complex signal in digital signal processing, or any method for calculating received power. . The received power calculation process may be performed with an RF signal or a baseband signal.

Based on the received power calculated by the received power calculator G, the weighted terminal position estimator F calculates the terminal estimated position Z _est of the wireless terminal T using the radio wave arrival direction calculated by the arrival direction estimator E. As will be described later, the weighted terminal position estimation unit F estimates the terminal position by performing weighting that increases the weight as the received power is higher, based on the received power.

  As the arrival direction estimation method, all methods for estimating the arrival direction using a plurality of antennas such as CMA (Constant Modulus Algorithm), MMSE (Minimum Mean Square Error), and MUSIC (Multiple Signal Classification) method are conceivable.

For comparison, FIG. 11 shows a configuration example of a conventional wireless terminal T1 when the configuration that is a feature of the present embodiment is not provided. In this configuration example, the wireless terminal T1 includes a plurality of reception antennas # 1 _T , # 2 _T ,..., _#MT , a base station determination unit I, an arrival direction estimation unit E, and a terminal position estimation unit H. Yes. In this configuration, the wireless terminal T1 uses the arrival direction estimation unit E to estimate the arrival direction of radio waves from each wireless base station, and determines the arrival direction estimation lines L _{1 to} L _N from the coordinates of each wireless base station. Then, the terminal position estimation unit H obtains the position of the wireless terminal T1 from the arrival direction estimation straight lines L _{1 to} L _N.

  Here, a method of calculating the terminal position in the weighted terminal position estimation unit F will be described in detail.

(1) First Weighted Terminal Position Estimation Method As a first weighted terminal position estimation method by the weighted terminal position estimation unit F, for example, as shown in FIG. 8, the intersection point P ₁₂ of the arrival direction estimation lines L ₁ and L ₂ is used. _Is the weight of the average value W _ave12 = mean (W ₁ , W ₂ ) of the received power W ₁ and W _{2, and} the average value of the received power W ₂ and W ₃ at the intersection P ₂₃ of the arrival direction estimation lines L ₂ and L _3. The weight of W _ave23 = mean (W ₂ , W ₃ ) is set to an average value W _ave of the received powers W _N−1 and W _N at the intersection P _{(N−1) N} of the arrival direction estimation straight lines L _N−1 and L _{N. (N-1)} Weights of _N = mean (W _N−1 , W _N ) are respectively multiplied by the intersection coordinates, and the positions of the plurality of intersections are represented by mean (W _ave12 P ₁₂ + W _ave23 P ₂₃ +... + W _{ave (N-1) NP (N- 1) N} ) The geometric load is averaged to determine the final terminal estimated position Z _est .

In the example illustrated in FIG. 8, the weighted terminal position estimation unit F includes an intersection calculation unit F-1 and a weight multiplication unit F-2. This intersection calculation unit F-1 receives equations (simultaneous equations) a ₁ x + b of arrival direction estimation lines L _{1 to} L _N of radio signals from the arrival direction estimation unit E from the radio base station apparatuses S0-1 to S0-N. _{1 y = c 1, a 2} x + b 2 y = c 2, ..., a N x + b N y = c receives information _N, the DOA estimation linear _L 1 ~L each intersection _P 12 of _{N, P 13,} ... , P _NM is calculated and output. In addition, the arrival direction estimation part E is an arrival direction estimation straight line from the estimated arrival direction of the radio wave from each radio base station apparatus S0-1 to S0-N and the coordinates of each radio base station S0-1 to S0-N. L _{1 to} L _N are determined. Weight multiplier unit F-2 is the intersection calculation unit F-1 with receiving information of the received power _W 1 to _W-N of a radio signal from each radio base station apparatus S0-1~S0-N from the received power calculation section G Based on the information of the calculated intersections P ₁₂ , P ₁₃ ,..., P _NM , for example, the terminal estimated position Z _est (estimated terminal position coordinates (x _est , y _est )) is calculated by the above method.

(2) Second Weighted Terminal Position Estimation Method As a second weighted terminal position estimation method by the weighted terminal position estimation unit F, for example, as shown in FIG. 8, the intersection point P ₁₂ of the arrival direction estimation lines L ₁ and L ₂ is used. _Is the weight of the maximum value W _max12 = max (W ₁ , W ₂ ) of the received power W ₁ and W _{2, and} the maximum value of the received power W ₂ and W ₃ at the intersection P ₂₃ of the arrival direction estimation lines L ₂ and L _3. The weight of W _max23 = max (W ₂ , W ₃ ) is set to the maximum value W _max of the received power W _N-1 and W _N at the intersection P _{(N-1) N} of the arrival direction estimation straight lines L _N-1 and L _{N. (N-1)} Weights of _N = max (W _N−1 , W _N ) are respectively multiplied by the intersection coordinates, and the positions of the plurality of intersections are _{expressed as} mean (W _max12 P ₁₂ + W _max23 P ₂₃ +... + W _{max (N-1) NP (N-1) N} ) and geometry The academic load is averaged, and the final terminal estimated position Z _est is determined.

(3) Third Weighted Terminal Position Estimation Method As a third weighted terminal position estimation method by the weighted terminal position estimation unit F, for example, as shown in FIG. 8, the intersection point P ₁₂ of the arrival direction estimation lines L ₁ and L ₂ is used. _Is the weight of the minimum value W _min12 = min (W ₁ , W ₂ ) of the received power W ₁ and W _{2, and} the minimum value of the received power W ₂ and W ₃ at the intersection P ₂₃ of the arrival direction estimation lines L ₂ and L _3. The weight of W _min23 = min (W ₂ , W ₃ ) is set at the intersection P _{(N−1) N} of the arrival direction estimation lines L _N−1 and L _N and the minimum value W _min of the received power W _N−1 and W _{N. (N-1)} Weights of _N = min (W _N−1 , W _N ) are respectively multiplied by the intersection coordinates, and the positions of the plurality of intersections are _{expressed as} mean (W _min12 P ₁₂ + W _min23 P ₂₃ +... + W _{min (N-1) NP (N-1) N} ) and geometry The academic load is averaged, and the final terminal estimated position Z _est is determined.

(4) Fourth Weighted Terminal Position Estimation Method As a fourth weighted terminal position estimation method by the weighted terminal position estimation unit F, for example, as shown in FIG. 9, arrival direction estimation straight lines L ₁ , L ₂ ,. _{A 1} x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ ,..., A _N x + b _N y = c _N , received power amplitude | W ₁ | ˜ | W _N |

As, than to be expressed as AZ = C, the pseudo-inverse of the matrix equation A as A ^+, multiplied by the A ⁺ from the left,

The obtained solution Z is defined as the final terminal estimated position Z _est .

FIG. 9 shows the weighted terminal position estimation unit F of FIG. 7 as a weighted terminal position estimation unit Fa. In this example, the weighted terminal position estimation unit Fa is composed of a weight multiplication unit Fa-3. This weight multiplication unit Fa-3 receives equations (simultaneous equations) a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ ,..., From the arrival direction estimation unit E to the arrival direction estimation lines L _{1 to} L _N. The terminal receives information on a _N x + b _N y = c _N , receives information on received power W _{1 to} W _N from the received power calculation unit G, performs pseudo inverse matrix operation as described above, and obtains a solution by obtaining a solution Estimated position Z _est (estimated terminal position coordinates (x _est , y _est )) is calculated.

(5) Fifth Weighted Terminal Position Estimation Method As a fifth weighted terminal position estimation method by the weighted terminal position estimation unit F, for example, as shown in FIG. 10, arrival direction estimation straight lines L ₁ , L ₂ ,. _N equation a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ ,..., A _N x + b _N y = c _N , received signal amplitude √ | W ₁ | ˜√ | W _N |

Since AZ = C can be expressed, the pseudo inverse matrix of the determinant A is defined as A ^+, and A ⁺ is multiplied from the left side,

The obtained solution Z is defined as the final terminal estimated position Z _est .

FIG. 10 shows the weighted terminal position estimator F of FIG. 7 as a weighted terminal position estimator Fb. In this example, the weighted terminal position estimation unit Fb is composed of a weight multiplication unit Fb-3. The weight multiplication unit Fb-3 receives equations (simultaneous equations) a ₁ x + b ₁ y = c ₁ , a ₂ x + b ₂ y = c ₂ ,... From the arrival direction estimation unit E and the arrival direction estimation lines L _{1 to} L _N. The terminal receives information on a _N x + b _N y = c _N , receives information on received power W _{1 to} W _N from the received power calculation unit G, performs pseudo inverse matrix operation as described above, and obtains a solution by obtaining a solution Estimated position Z _est (estimated terminal position coordinates (x _est , y _est )) is calculated.

  According to the second embodiment described above, the terminal position can be estimated based on the reliability of each arrival direction estimation line, and the terminal position estimation accuracy can be improved.

  As described above, according to the present invention, by using three or more radio base stations, the reception power is calculated for each radio base station, and three or more are calculated based on the reception power for each radio base station. The position of the terminal can be estimated from the arrival direction estimation straight line. Therefore, in this case, the terminal position can be estimated based on the reliability of each arrival direction estimation line, and the terminal position estimation accuracy can be improved.

  Further, according to the present invention, the intersection of the arrival direction estimation straight lines is weighted based on the average value, the maximum value, or the minimum value of the received power related to the two radio base station devices that calculated the intersection, The position of the intersection is determined as an end position by averaging the geometrical load. Therefore, it is possible to estimate the terminal position based on the reliability of each arrival direction estimation line, and it is possible to improve the terminal position estimation accuracy.

  In addition, according to the present invention, the equation of the arrival direction estimation line is weighted based on the received power, a solution of the weighted equation is obtained by a pseudo inverse matrix operation, and the solution is determined as the terminal position. Therefore, it is possible to estimate the terminal position based on the reliability of each arrival direction estimation line, and it is possible to improve the terminal position estimation accuracy.

  In addition, when the present invention is not applied, for example, the accuracy of the terminal position detection deteriorates. Therefore, when performing position detection in a wireless system, the base station cannot increase the radio cell size, and covers a wide area. Needed a lot of base stations. However, according to the present invention, there is an effect of reducing the number of base stations by increasing the radio cell size.

  The embodiment of the present invention is not limited to the above. For example, as a configuration combining the first embodiment and the second embodiment, the position detection according to the present invention can be performed by either the base station or one or a plurality of terminals. The configuration shown in each block diagram can be further divided, configured in a distributed manner, or distributed, or integrated to reduce the number of components, and further a terminal location estimation method (for example, It is possible to appropriately make changes such as preparing a plurality of estimation methods (1) to (5) of the first embodiment and switching them as appropriate or selectively adopting the results so that they can be used simultaneously.

An example of the characteristic evaluation (simulation) result of the above embodiment will be described with reference to FIGS. FIG. 12 shows the arrangement of the base stations and other conditions used in the characteristic evaluation, and FIG. 13 shows the wireless communication specifications used in the characteristic evaluation. FIG. 14 shows the relationship between the cell radius obtained by the characteristic evaluation and the RMS value (effective value) of the positioning error. The above (4) fourth weighted terminal position estimation method, that is, the case where the absolute values | W ₁ | to | W _N | of received power are used is referred to as proposed method 1 (circle), and (5) fifth weighted terminal position The estimation method, that is, the case where the received power amplitude √ | W ₁ | ˜√ | W _N | is used is proposed method 2 (Δ mark), and the case where weighting by received power is not performed is the background art method (□ mark). Show. Further, a no-noise environment is indicated by a broken line, and a noisy environment is indicated by a solid line. Although there are differences depending on the method, the proposed method shows better characteristics than the background art method.

1 is a block diagram illustrating a wireless device according to a first embodiment. It is a block diagram showing the detail of the 1st-3rd weighting terminal position estimation method in the weighting terminal position estimation part C. It is a block diagram showing the detail of the 4th weighting terminal position estimation method in the weighting terminal position estimation part C. It is a block diagram showing the detail of the 5th weighting terminal position estimation method in the weighting terminal position estimation part C. It is a block diagram which shows the radio | wireless apparatus as background art. It is a block diagram which shows the radio | wireless apparatus by 2nd Embodiment. It is a block diagram which shows the radio | wireless apparatus by 2nd Embodiment. It is a block diagram showing the detail of the 1st-3rd weighting terminal position estimation method in the weighting terminal position estimation part F. It is a block diagram showing the detail of the 4th weighting terminal position estimation method in the weighting terminal position estimation part F. It is a block diagram showing the detail of the 5th weighting terminal position estimation method in the weighting terminal position estimation part F. It is a block diagram which shows the radio | wireless apparatus as background art. It is a figure for demonstrating the characteristic evaluation result by the Example of this invention. It is a figure for demonstrating the characteristic evaluation result by the Example of this invention. It is a figure for demonstrating the characteristic evaluation result by the Example of this invention.

Explanation of symbols

# 1 ₁ , # 2 ₁ ..., #M ₁ , # 1 ₂ , # 2 ₂ , ... #M ₂ , ... # 1 _N , # 2 _N , ... #M _N , # 1 _T , # 2 _T ..., # M _T receive antennas A1, A2, ..., AN, G received power calculator B1, B2, ..., BN, E arrival direction estimation unit C, Ca, Cb, F weighted terminal position estimating portion C-1, F-1 intersection Calculation unit C-2, Ca-3, Cb-3, F-2, Fa-3, Fb-3 Weight multiplication unit D, H Terminal position estimation unit I Base station determination unit T, T0 Wireless terminals S0,. Wireless base station equipment

Claims (14)

Estimating the position of the terminal based on the arrival direction of the radio signal between the terminal and the base station having a plurality of antennas and three or more base stations installed at locations apart from each other, and the base station, A terminal location estimation system comprising a location estimation device installed in any of the base stations or independently of the terminal and the base station,
The base station
Received power measuring means for measuring received power of a received signal from the terminal received by each of a plurality of antennas;
Arrival direction estimation means for estimating the arrival direction of radio waves from the received signal;
Comprising
The position estimation device includes:
Arrival direction estimation straight line calculating means for calculating the arrival direction estimation straight line of each base station from the arrival direction of the radio wave estimated by the arrival direction estimating means of the base station and the coordinates of the base station;
Based on the arrival direction estimation line of each base station calculated by the arrival direction estimation line calculation means and the reception power measured by the reception power measurement means of each base station, the higher the reception power, the larger the weight. Terminal position estimating means for estimating the position of the terminal by performing weighting
A terminal position estimation system characterized by the above. The base station comprises the direction-of-arrival estimation straight line calculation means instead of the position estimation device installed independently of the base station,
The arrival direction estimation line calculation means calculates the arrival direction estimation line from the arrival direction estimated by the arrival direction estimation means of the own base station and the coordinates of the own base station,
The terminal position estimation system according to claim 1. A terminal comprising a terminal having a plurality of antennas and three or more base stations installed at locations distant from each other, and estimating the position of the terminal based on the arrival direction of the radio signal between the terminal and the base station In the position estimation system,
The terminal
Received power measuring means for measuring the received power of the received signal from each base station received by each of the plurality of antennas;
Arrival direction estimation means for estimating the arrival direction of each radio wave from the received signal from each base station;
An arrival direction estimation line calculation means for calculating an arrival direction estimation line from the arrival direction of each radio wave estimated by the arrival direction estimation means and the coordinates of the base station of the transmission source of each radio wave;
Based on the arrival direction estimation line of the radio wave from each base station calculated by the arrival direction estimation line calculation unit and the reception power from the base station measured by the reception power measurement unit, the reception power is high Terminal position estimation means for estimating the position of the terminal by weighting to increase the weight as much as possible,
A terminal position estimation system characterized by the above. The terminal position estimating means
Intersection calculating means for calculating an intersection of each of the two arrival direction estimation straight lines;
Weight calculation means for weighting the calculated intersection using the reception level measured by the reception power measurement means and estimating the position of the terminal by geometrically averaging the positions of the plurality of weighted intersections The terminal position estimation system according to any one of claims 1 to 3, further comprising: The terminal position estimating means
Weighting using the received level measured by the received power measuring means for the equation of the direction of arrival estimation straight line,
The terminal position estimation system according to any one of claims 1 to 3, wherein the terminal position is estimated by performing a pseudo inverse matrix operation on the plurality of weighted arrival direction estimation linear equations after weighting. Estimating the position of the terminal based on the arrival direction of the radio signal between the terminal and the base station having a plurality of antennas and three or more base stations installed at locations apart from each other, and the base station, A terminal location estimation method used in a terminal location estimation system comprising a location estimation device installed in any of the base stations or independently of the terminal and the base station,
The base station is
A received power measurement process for measuring received power of a received signal from the terminal received at each of a plurality of antennas;
A direction-of-arrival estimation process for estimating a direction of arrival of radio waves from the received signal;
The position estimation device is
A direction-of-arrival estimation straight line calculation process for calculating the direction-of-arrival estimation straight line of each base station from the direction of arrival of radio waves estimated in the direction of arrival estimation of the base station and the coordinates of the base station;
Based on the arrival direction estimation straight line of each base station calculated in the arrival direction estimation straight line calculation process and the reception power measured in the reception power measurement process of each base station, the higher the received power, the larger the weight. And a terminal position estimation process for estimating the position of the terminal by performing weighting. Instead of the position estimation device installed independently of the base station, the base station performs the arrival direction estimation straight line calculation process of the base station,
In the direction-of-arrival estimation line calculation process, the direction-of-arrival estimation line is calculated from the direction of arrival estimated in the direction-of-arrival estimation process and the coordinates of the own base station.
The terminal position estimation method according to claim 6. A terminal comprising a terminal having a plurality of antennas and three or more base stations installed at locations distant from each other, and estimating the position of the terminal based on the arrival direction of the radio signal between the terminal and the base station A terminal position estimation method in a position estimation system,
The terminal is
A received power measurement process for measuring received power of a received signal from each base station received by each of a plurality of antennas;
A direction-of-arrival estimation process for estimating the direction of arrival of each radio wave from the received signal from each base station;
An arrival direction estimation straight line calculation process for calculating an arrival direction estimation straight line from the arrival direction of each radio wave estimated in the arrival direction estimation process and the coordinates of the base station of the transmission source of each radio wave;
Based on the arrival direction estimation straight line of the radio wave from each base station calculated in the arrival direction estimation straight line calculation process and the reception power from the base station measured in the reception power measurement process, the reception power is high A terminal position estimation process for estimating the position of the terminal by performing weighting to increase the weight as much as possible. The terminal location estimation process includes:
An intersection calculation process for calculating an intersection of each of the two arrival direction estimation straight lines;
A weight calculation process for estimating the terminal position by weighting the calculated intersection using the reception level measured in the received power measurement process and geometrically averaging the positions of the plurality of weighted intersections The terminal location estimation method according to claim 6, comprising: In the terminal location estimation process,
Weighting with respect to the equation of arrival direction estimation straight line using the reception level measured in the received power measurement process,
The terminal position estimation method according to any one of claims 6 to 8, wherein the terminal position is estimated by performing a pseudo inverse matrix operation on the plurality of weighted direction-of-arrival estimation linear equations after weighting. Estimating the position of the terminal based on the arrival direction of the radio signal between the terminal and the base station having a plurality of antennas and three or more base stations installed at locations apart from each other, and the base station, The position estimation apparatus in a terminal position estimation system comprising any one of the base stations or a position estimation apparatus installed independently of the terminal and the base station,
Direction of arrival estimation for each base station is calculated from the direction of arrival of radio waves estimated from received signals from the terminals received by the base station at each of a plurality of antennas and the coordinates of the base station. Straight line calculation means;
A terminal that estimates the position of a terminal by performing weighting to increase the weight as the received power is higher, based on the arrival direction estimation line of each base station and the received power of the received signal measured at each base station A position estimation device comprising: position estimation means. The base station comprises the arrival direction estimation line calculation means instead of the position estimation device installed independently of the base station,
The terminal position estimation means receives a reception direction based on an arrival direction estimation straight line calculated from an arrival direction of radio waves estimated by the base stations and coordinates of the base station, and the received power measured at the base stations. Estimate the position of the terminal by weighting to increase the weight as the power is higher,
The position estimation apparatus according to claim 11. The terminal position estimating means
Intersection calculating means for calculating an intersection of each of the two arrival direction estimation straight lines;
Weight calculation means for weighting the calculated intersection using the reception level measured by the reception power measurement means and estimating the position of the terminal by geometrically averaging the positions of the plurality of weighted intersections The position estimation apparatus according to claim 11 or 12, characterized by comprising: The terminal position estimating means
Weighting using the received level measured by the received power measuring means for the equation of the direction of arrival estimation straight line,
The position estimation apparatus according to claim 11 or 12, wherein the position of the terminal is estimated by performing a pseudo inverse matrix operation on the plurality of weighted arrival direction estimation linear equations after weighting.

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