JP2007198742A - Positioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with cable connection used for synchronizing sensors with each other corresponding to the disposition of sensors and to the movement, etc. of the sensor themselves; and to correct clock errors among the sensors by performing processing in a positioning device in order to dispense with a transmission station used for correcting the clock errors. <P>SOLUTION: This positioning device for receiving a radio wave emitted from or reflected by a target by means of a plurality of sensors to calculate the position of the target based on incoming time differences of the received radio wave, is equipped with an incoming time difference calculation part for calculating the incoming time differences of the radio wave received a plurality of times by the respective sensors, and a position measurement part for measuring the clock errors among the sensors and the positions of the target at respective time points when the radio wave is received based on incoming time differences among the respective sensors. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positioning device that receives a radio wave radiated or reflected from a target whose position is to be known and calculates the position of the target.

  In the positioning device, radio waves radiated or reflected from the target are received by multiple sensors, and the position of the target is calculated based on the arrival time difference between the received radio waves. It is necessary to receive at the correct timing. For this purpose, it is necessary for each sensor to establish highly accurate time synchronization. The sensors are connected by a cable, and the sensors are operated in synchronization with each other with the same clock. However, when multiple sensors are installed in close proximity, they can be connected together using a wiring board, etc., but when the sensors are installed at positions separated from each other, individual cables can be connected between the sensors. It is necessary to prepare a large number of cables for the connection and connection work, which is disadvantageous in terms of cost. In addition, when the sensors themselves move, it is difficult to connect the sensors with cables. As a method for solving this problem, there is a method in which the arrival time of radio waves is observed with each sensor including a clock error, and the clock error is corrected by subsequent processing (see, for example, Patent Document 1). In the method of Patent Document 1, a transmitting station is placed at a known position, radio waves from the transmitting station are received by each sensor, and a time difference between the radio waves is calculated to calculate a clock error between the sensors. Is. When calculating the target position, the arrival time difference of the radio wave from the target is corrected with the previously determined clock error, and the target position is calculated based on the correction value.

JP 2001-272448 A

  In the conventional positioning device, the arrival time difference of the radio wave from the target is corrected using a previously determined clock error, and the target position is calculated based on the correction value. In order to obtain this, it is necessary to provide a separate transmission station, and the apparatus becomes large correspondingly.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a positioning device that enables correction of a clock error between sensors by processing within the own device.

  A positioning device according to the present invention is a positioning device that receives a radio wave radiated or reflected from a target by a plurality of sensors and calculates a target position based on a difference in arrival time of the received radio waves, and is received by each sensor a plurality of times. An arrival time difference calculation unit that calculates the arrival time difference of the received radio wave, and a positioning unit that measures the clock error between the sensors and the target position at each time when the radio wave is received based on the calculated arrival time difference between the sensors. It is provided.

  According to the present invention, the arrival time of radio waves is observed with a clock error included between the sensors, and the clock error is corrected in the subsequent positioning process. Therefore, there is no need to consider cable connection for synchronization between sensors, and there is no need to separately install a transmitting station for correcting clock errors.

Embodiment 1 FIG.
1 is a block diagram showing a functional configuration of a positioning apparatus according to Embodiment 1 of the present invention.
In the figure, a plurality of sensors 1 ₁ to 1 _N (N ≧ 5) are means for receiving a radio wave emitted from a target or reflected by the target a plurality of times. The arrival time difference calculation unit 2 is a means for calculating the arrival time difference of radio waves received by each sensor a plurality of times. The positioning unit 3 is means for calculating a clock error between the sensors and a target position at each time when the radio wave is received based on the arrival time difference of the radio wave between the sensors. The positioning unit 3 includes a collective positioning unit 31. The collective positioning unit 31 calculates an equation that the distance obtained by multiplying the time difference of the radio waves by the time of subtracting the clock error between the sensors and the speed of the radio waves is equal to the difference in the radio wave propagation distance. It is a means for measuring the position of the target at each time at which the clock error between the sensors and the radio wave are received by creating a plurality of times at the reception time.

Next, the principle of the present invention will be described.
In the sensor 1 ₁ to 1 _N, emitted from the target, or when receiving the radio wave reflected by a target, the sensor observes the arrival time which has received the radio wave. This method will be described by taking sensor _n (1 ≦ n ≦ N) as an example. First, in the sensor _n , the received signal is down-converted to a low frequency and converted into a digital signal by an A / D converter (sampling time is set to Δt). The digital received signal of the sensor 1 _n when the digital signal sampling number is i is represented as x _n (i). Here, it is assumed that the signal waveform of the radio wave from the target is known, and the known signal waveform is hereinafter referred to as a reference signal and represented by x _r (i). However, it is assumed that the reference signal has been converted to the same frequency as the signal received by the sensor. Then, the number of points (integer) in the correlation process is set to L, and the sample point h is varied to obtain h that maximizes the magnitude | f _n (h) | of the correlation function f _n (h) in the equation (1). Note that x _r (i) ^* means a complex conjugate of x _r (i).

Now, suppose that | f _n (h) | becomes maximum when h = h _n . Since this indicates that the signal received by the sensor 1 _n is similar to the reference signal, h _n · Δt is the arrival time τ _{n at} which the sensor 1 _n received the radio wave from the target.
τ _n = h _n · Δt (2)
In the following, since the arrival times observed at a plurality of times are handled, the arrival time observed by the sensor 1 _n at the time t _k is represented as τ _n ^(k) .
Each sensor observes radio wave arrival times τ _n ^(k) (1 ≦ n ≦ N, 1 ≦ k ≦ K) at a plurality of different times t _k (1 ≦ k ≦ K) as described above. It transmits to the arrival time difference calculation unit 2. Hereinafter, t _k is referred to as observation time.

そして、ｆ’_n,m（ｈ）が最大となるｈを求め、これにΔｔを乗じたものが、電波の到来時間差Δτ_n,m となる。
Δτ_n,m ＝ｈ・Δｔ
これまでの説明では、相関処理を用いて到来時間差を求める方法について説明したが、これに限らず、他の方式により求めた到来時間差を求めてもよい。 The arrival time difference calculation unit 2 calculates the arrival time difference of the radio wave from the target received by each sensor at the observation time t _k (1 ≦ k ≦ K) output from the sensors 1 ₁ to 1 _N. Now, at the observation time t _k , the arrival time of the radio wave received by the sensor 1 _n (1 ≦ n ≦ N) is τ _n ^(k) , and the radio wave received by the sensor 1 _m (1 ≦ m ≦ N, n ≠ m). Is the arrival time τ _m ^(k) . In this case, the arrival time difference calculation unit 2 calculates the arrival time difference Δτ _{n, m} ^(k) of the radio wave at the observation time t _{k according to the} equation (3).
Δτ _{n, m} ^(k) = τ _n ^(k) −τ _m ^(k) (3)
In the above description, the radio wave from the target is known. However, the arrival time can be obtained even when the radio wave is unknown. Specifically, the digital signal x _n (i) received by the sensor 1 _n and the digital signal x _m (i) received by the sensor 1 _m are transmitted, and correlation processing as shown in the equation (4) is performed. .

Then, h that maximizes f ′ _{n, m} (h) is obtained, and this is multiplied by Δt to obtain a radio wave arrival time difference Δτ _{n, m} .
Δτ _{n, m} = h · Δt
In the description so far, the method of obtaining the arrival time difference using the correlation processing has been described. However, the present invention is not limited to this, and the arrival time difference obtained by another method may be obtained.

ここで［Ｘ_n ，Ｙ_n ，Ｚ_n ］はセンサ１_n の座標（既知）、［Ｘ_m ，Ｙ_m ，Ｚ_m ］はセンサ１_m の座標（既知）とする。観測時刻ｔ_k における上記の様な方程式は、センサ数マイナス１成立するため、センサの総数をＮ個とすれば、（Ｎ−１）成立する。また、目標からの電波を受信した時刻の回数をＫ（観測時刻はｔ_k （１≦ｋ≦Ｋ），ｋは自然数）とすれば、各観測時刻ｔ_k で（５）式のような方程式は（Ｎ−１）個成り立つため、観測回数がＫ個の場合には、全部で（Ｎ−１）×Ｋ個成り立つ。 The positioning unit 3 generates a plurality of equations in the collective positioning unit 31 based on the arrival time difference Δτ _{n, m} ^(k) (n ≠ m, 1 ≦ k ≦ K) of the radio wave output from the arrival time difference calculation unit 2. The target position is calculated by solving them. A specific processing method will be described.
The time difference Δτ _{n, m} ^(k) of radio waves at the observation time t _k of the sensor 1 _n and the sensor 1 _m includes a clock error. If this clock error is ε _{n, m} (unknown number), (Δτ _{n, m} ^(k) −ε _{n, m} ) is the arrival time difference that does not include the clock error. For this reason, the distance obtained by multiplying (Δτ _{n, m} ^(k) −ε _{n, m} ) by the velocity c of the radio wave is equal to the difference between the distance from the sensor 1 _n to the target and the distance from the sensor 1 _m to the target. Therefore, equation (5) is established.

Here, [X _n , Y _n , Z _n ] is the coordinate (known) of the sensor 1 _n , and [X _m , Y _m , Z _m ] is the coordinate (known) of the sensor 1 _m . The above equation at the observation time t _k is satisfied by the number of sensors minus 1. Therefore, if the total number of sensors is N, (N−1) is satisfied. Further, if the number of times of reception of radio waves from the target is K (observation time is t _k (1 ≦ k ≦ K), k is a natural number), an equation like equation (5) at each observation time t _k Since (N−1) holds, if the number of observations is K, (N−1) × K holds in total.

On the other hand, the unknowns in equation (5) are related to the target position [x ^(k) , y ^(k) , z ^(k) ] and related to the clock error ε _{n, m} . Among these, the unknowns [x ^(k) , y ^(k) , z ^(k) ] of the target positions are different for each observation time t _k (1 ≦ k ≦ K), and therefore, when the number of observation times is K, 3 × K. Further, the clock error ε _{n, m} between the sensors is considered not to fluctuate abruptly, and therefore becomes constant regardless of the radio wave observation time t _k (1 ≦ k ≦ K) and becomes (N−1). Therefore, the total number of unknowns included in (N−1) × K equations is ((N−1) + 3K). Therefore, when the condition of the expression (6) is satisfied, the unknown number is equal to the equation, and the unknown number can be determined. However, since the arrival time difference may include an observation error, the equation (5) does not always intersect at one point. In this case, the unknown is calculated by obtaining a least square solution.
(N−1) × K = (N−1) + 3K (6)
For example, when the number of sensors N is 5, the number of observations K is 4, and an unknown number can be determined. If there are more equations than unknowns, the least squares solution is obtained to calculate the unknowns.
The collective positioning unit 31 calculates the unknowns (target position and clock error) as described above.

The positioning unit 3 may include a motion model setting unit 32 and a motion model positioning unit 33 as shown in FIG. In this case, the motion model setting unit 32 sets whether the target movement whose position is to be known is constant velocity linear motion, constant acceleration linear motion, or the like. The motion model positioning unit 33 creates a plurality of equations based on the result set by the motion model setting unit 32, and calculates the target position by combining these equations.
An example in which the constant velocity linear motion is set by the motion model setting unit 32 will be described below.
In the case of constant velocity linear motion, the target position [x ^(k) , y ^(k) , z ^(k) ] at the observation time t _k can be expressed as in equations (7) to (9).
x ^(k) = x ⁽¹⁾ + v _x · Δt _k (7)
y ^(k) = y ⁽¹⁾ + v _y · Δt _k (8)
z ^(k) = z ⁽¹⁾ + v _z · Δt _k (9)
Δt _k = t ₁ −t _k (10)
An equation created by the motion model positioning unit 33 is obtained by substituting this into equation (5), and is as shown in equation (11).

Assuming that the number of sensors is N and the number of observations is K, (N−1) × K of these equations are obtained as in the case of the collective positioning unit 31. On the other hand, the unknowns are the target position [x ⁽¹⁾ , y ⁽¹⁾ , z ⁽¹⁾ ] at the observation time t _1, the target speed [v _x , v _y , v _z ], the clock error ε _{n, m} Become. The number of unknowns (the position of the observation time t ₁ and the target speed) regarding the target position is a constant value 6 regardless of the observation time t _k , and the number of clock errors is the same as in the case of the collective positioning unit 31 ( N-1). Therefore, the condition for obtaining an equation more than the number of unknowns is as shown in equation (12). However, since the arrival time difference may include an observation error, the equation (12) does not always intersect at one point. In this case, the unknown is calculated by obtaining a least square solution.
(N−1) × K ≧ (N−1) +6 (12)
For example, when the number of sensors N is 5, K ≧ 5/2. Therefore, it is possible to estimate the unknown even when the number of observations K = 3. Since the collective positioning unit 31 has K ≧ 4 when N = 5, the motion model setting unit 33 can calculate the target position with a smaller number of observations. If there are more equations than unknowns, the unknowns are calculated by solving a least squares solution.
The motion model positioning unit 33 calculates a target position and a clock error by solving a large number of equations such as the equation (11) as described above and solving them. It should be noted that the conditions under which the target position can be measured shown in Expression (12) are different depending on the exercise model set by the exercise model setting unit 32.

  As described above, according to the first embodiment, based on the arrival time difference between the sensors calculated by the arrival time difference calculation unit 2, the clock error between the sensors and the target position at each time when the radio waves are received are determined. In particular, the positioning unit 3 is obtained by multiplying the time obtained by subtracting the clock error between the sensors from the difference in radio wave arrival time between the sensors in the collective positioning unit 31 by the radio wave speed. The equation that the distance is equal to the difference in the propagation distance of the radio wave is created for each radio wave reception time, and by combining these equations, the clock error between the sensors and the target position at each time the radio wave is received I am trying to calculate. Therefore, it is possible to correct a clock error between sensors in the positioning device. Therefore, there is no need to synchronize between sensors, there is no need to consider cable connection for synchronizing sensors in accordance with sensor placement, sensor movement, etc., and to correct clock errors There is no need to install a separate transmitter station.

なお、測位処理制御部３７から出力された電波の補正到来時間差Δτ’_n,m ^(k)が無い場合は、到来時間差算出部２から出力された到来時間差Δτ_n,m ^(k)そのものを電波の補正到来時間差Δτ’_n,m ^(k)の代わりに、（１３）式に代入して目標の暫定位置を算出する。 Embodiment 2. FIG.
FIG. 3 is a block diagram showing a functional configuration of a positioning apparatus according to Embodiment 2 of the present invention. In the figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted in principle. The positioning unit 3 according to the second embodiment includes a provisional positioning unit 34, a mismatch time calculation unit 35, a provisional clock error calculation unit 36, and a positioning process control unit 37.
The provisional positioning unit 34, 'with _{n, m} and ^(k), (13) a target in temporary position at the measurement time t _k by equation [x' radio wave correction TDOA Δτ outputted from the positioning process controller 37 ^{( k)} , y ' ^(k) , z' ^(k) ].

If there is no corrected arrival time difference Δτ ′ _{n, m} ^{(k) of} the radio wave output from the positioning processing control unit 37, the arrival time difference Δτ _{n, m} ^(k) itself output from the arrival time difference calculation unit 2 is used as the radio wave. Instead of the corrected arrival time difference Δτ ′ _{n, m} ^(k) , the target provisional position is calculated by substituting into the equation (13).

Unlike the formula (5) of the collective positioning unit 31 of the first embodiment, the temporary positioning unit 34 estimates a temporary target position that ignores the clock error. The unknown in equation (13) is only the target provisional position [x ′ ^(k) , y ′ ^(k) , z ′ ^(k) ], and therefore provisional if an equation such as equation (13) holds 3 or more. The position can be calculated. Since the positioning equation (13) is established with the number of sensors minus one, the target provisional position can be calculated when the number of sensors N is 4 or more. However, since the radio wave arrival time difference Δτ _{n, m} ^(k) includes a clock error, the positioning equation (13) does not always intersect at one point. In that case, the target provisional position is calculated so as to obtain a least squares solution. Further, even when there are more equations than unknowns, the target provisional position is calculated by obtaining the least squares solution.
The provisional position measurement unit 34 obtains the target provisional position as described above, and outputs the target provisional position to the mismatch time calculation unit 35.

ミスマッチ時間算出部３５では、上記の様にして算出したミスマッチ時間を暫定時計誤差算出部３６に出力する。 The mismatch time calculation unit 35 subtracts the time obtained by dividing the difference between the target temporary position obtained by the temporary position measurement unit 34 and the distance between each sensor by the speed of the radio wave from the arrival time difference of the radio wave between the sensors. Then, it is calculated as a mismatch time at each time. This process is expressed by equation (14). A difference between the target temporary position output from the temporary positioning unit 34 and the distance between the sensor 1 _n and the target temporary position and the distance between the sensor 1 _m is obtained. Next, the time (the second term of the equation) is obtained by dividing the difference between the target temporary position and the distance of each sensor by the radio wave velocity c. The obtained time (the second term of the equation) is subtracted from the arrival time difference Δτ _{n, m} ^{(k) of} the radio wave output from the arrival time difference calculation unit 2 to obtain a mismatch time ε ′ _{n, m} ^(k) .

The mismatch time calculation unit 35 outputs the mismatch time calculated as described above to the provisional clock error calculation unit 36.

また、暫定時計誤差算出部３６は、図５に示すように重み付け処理部３６２を備えてもよい。この場合、重み付け処理部３６２で、ミスマッチ時間算出部３５から出力されたミスマッチ時間ε’_n,m ^(k)に後述の重み付け係数ψ_n,m ^(k)を乗算することで重み付けを行い、センサ間の暫定時計誤差ε’’_n,mとして算出する。 The mismatch time ε ′ _{n, m} ^(k) is due to the clock error between sensors. Therefore, the provisional clock error calculation unit 36 calculates a provisional clock error based on the mismatch time at each time. The provisional clock error calculation unit 36 includes an average processing unit 361 as shown in FIG. The average processing unit 361 obtains an average value for the mismatch time ε ′ _{n, m} ^(k) (1 ≦ k ≦ K) of the sensor 1 _n and the sensor 1 _m as shown in the equation (15), and this is obtained as the sensor 1 _Let tentative clock error ε ″ _{n, m} for _n and sensor 1 _m .

Further, the provisional clock error calculation unit 36 may include a weighting processing unit 362 as shown in FIG. In this case, the weighting processing unit 362 performs weighting by multiplying the mismatch time ε ′ _{n, m} ^(k) output from the mismatch time calculation unit 35 by a weighting coefficient ψ _{n, m} ^(k), which will be described later. Calculated as the interim clock error ε ″ _{n, m} .

次に、関数ｇ_n,m （ｘ，ｙ，ｚ）を用いて、（１７）式に示す行列Ａ_n,mを求める。

ここで、行列Ａ_n,m の各成分は、暫定測位部３４から出力された目標の暫定位置［ｘ’^(k) ，ｙ’^(k) ，ｚ’^(k) ］を用いて求める。一例を（１８）式に示す。

The weighting coefficient ψ _{n, m} ^(k) is, for example, the geometry of the target position and the sensor position described in “New GPS Survey Fundamentals”, Takuya Tsuchiya, written by Hiromichi Tsuji, edited by Japan Surveying Association. The target position estimation accuracy reduction rate (geometric low accuracy reduction rate: GDOP) obtained from the physical relationship may be used. Here, a method of calculating the weighting coefficient ψ _{n, m} ^(k) will be described.
Now, it is assumed that the number of sensors N is 4, and the provisional position of the target calculated by the provisional positioning unit 34 is [x ′ ^(k) , y ′ ^(k) , z ′ ^(k) ]. Then, the provisional position of the goal, and the equation of the sensor 1 ₁ and the sensor 1 _2, and the equation of the sensor 1 ₂ and the sensor 1 _3, and the equation of the sensor 1 ₃ and the sensor 1 ₄ in which is calculated based on To do. Here, the function g _{n, m} (x, y, z) is defined as in equation (16).

Next, using the function g _{n, m} (x, y, z), a matrix A _{n, m} shown in equation (17) is obtained.

Here, each component of the matrix A _{n, m} is obtained using the target provisional positions [x ′ ^(k) , y ′ ^(k) , z ′ ^(k) ] output from the provisional positioning unit 34. An example is shown in equation (18).

重み付け処理部３６２では、（２０）式により求めた重み付け係数φ_n,m ^(k)を用いて、ミスマッチ時間算出部３５で算出されたミスマッチ時間ε’_n,m ^(k)を重み付けして、（２１）式により暫定時計誤差ε’’_n,m を算出し出力する。

Finally, a matrix W _{n, m} shown in Equation (19) is obtained.
W _{n, m} = (A _{n, m} ^H · A _{n, m} ) ⁻¹ (19)
Here, A _{n, m} ^H represents the complex conjugate transpose of the matrix A _{n, m} , and (A _{n, m} ^H · A _{n, m} ) ⁻¹ represents the matrix (A _{n, m} ^H · A _{n, m} ). Represents the inverse matrix of.
The weighting coefficient φ _{n, m} ^(k) is calculated based on the diagonal component of the matrix W _{n, m} as shown in equation (20).

The weighting processing unit 362 weights the mismatch time ε ′ _{n, m} ^(k) calculated by the mismatch time calculating unit 35 using the weighting coefficient φ _{n, m} ^(k) obtained by the equation (20), The provisional clock error ε ″ _{n, m} is calculated and output by equation (21).

The positioning process control unit 37 subtracts the provisional clock error calculated by the provisional clock error calculation unit 36 from the arrival time difference of the radio wave to obtain a correction value, and uses the obtained correction value for correction reception of the radio wave used by the provisional positioning unit 34. Output as time difference. In addition, the positioning process control unit 37 completes a series of positioning processes by the provisional positioning unit, the mismatch time calculation unit, and the provisional clock error calculation unit according to the determination criteria in the process of calculating the correction value of the arrival time difference, The target provisional position and provisional clock error obtained in each process are output as the final target position and clock error, or a series of positioning processes are continuously performed again to perform the positioning process again.
The positioning processing control unit 37, the arrival time difference .DELTA..tau _n of radio _waves, in order to correct the _m ^{(k), (22)} as shown in equation TDOA .DELTA..tau _n radio _{waves, m} ^(k) Provisional clock error from epsilon '_'n, subtracts the _m, radio waves corrected arrival time difference Δτ' _{n, m} ^{(k) is} determined. The corrected arrival time difference of the radio wave is used by the temporary positioning unit 34 to calculate the target temporary position at each time as described above.
Δτ ′ _{n, m} ^(k) = Δτ _{n, m} ^(k) −ε ″ _{n, m} (1 ≦ k ≦ K) (22)
Further, the positioning processing control unit 37 includes a processing number counting unit 371 as shown in FIG. 6 in order to determine whether or not the positioning processing is continued. The processing count counting unit 371 counts the number of times a series of processing has been performed by the temporary positioning unit 34, the mismatch time calculation unit 35, and the provisional clock error calculation unit 36, and the count number reaches a preset value (determination criterion). In such a case, it is determined that a series of positioning processes is completed. At this time, the positioning process control unit 37 determines the target provisional position [x ′ ^(k) , y ′ ^(k) z ′ ^(k) ] output from the temporary positioning unit 34 in the last process as the target to be obtained. The position and clock error are output, and the temporary clock error ε ″ _{n, m} output from the temporary clock error calculator 36 in the last process is output as the clock error of the sensors 1 _n and 1 _m . On the other hand, when the processing number counting unit 371 does not reach the preset value, it is determined that the series of positioning processing is to be continued again, and the positioning processing control unit 37 calculates the equation (22). To correct the arrival time difference, output the corrected arrival time difference of the radio wave to the temporary positioning unit 34, and perform a series of positioning processes again.

Further, the positioning processing control unit 37 may include a residual processing unit 372 as shown in FIG. In this case, the residual processing unit 372 calculates a difference (residual) between the target provisional position obtained in the current process and the target provisional position obtained in the previous process, and this residual is set in advance. If it is smaller than the measured value (determination criterion), it is determined that a series of positioning processes are completed. At this time, the positioning process control unit 37 outputs the target temporary position and the temporary clock error obtained in the current process as the target position and the clock error to be obtained. On the other hand, in the residual processing unit 372, when the residual is larger than a preset value, it is determined that the series of positioning processing is to be continued again, and the positioning processing control unit 37 arrives according to the equation (22). The time difference is corrected, the corrected arrival time difference of the radio wave is output to the temporary positioning unit 34, and a series of positioning processes is performed again.
In addition, the continuation or completion of a series of positioning processes may be determined based on the residual of the temporary clock error obtained by the temporary clock error calculation unit 36, or the temporary clock error residual and the target provisional You may make it carry out using both of the residual of a position.
Further, the positioning processing control unit 37 includes both a processing count counting unit 371 and a residual processing unit 372, and combines a series of positioning processing and a residual of a target position or a residual of a clock error by combining a series of positioning processing. It may be determined whether processing is continued or completed.

  As described above, according to the second embodiment, the positioning unit 3 uses the provisional positioning unit 34 to calculate the distance obtained by multiplying the corrected arrival time difference of radio waves between sensors by the speed of radio waves. Is created for each reception time of radio waves, and these equations are combined to calculate the provisional position of the target at each time. In the mismatch time calculation unit 35, the target time The time obtained by dividing the difference between the provisional position and the distance of each sensor by the velocity of the radio wave is subtracted from the difference in the arrival time of the radio wave between the sensors to calculate the mismatch time at each time, and the provisional clock error calculation unit 36 Thus, a provisional clock error between the sensors is calculated based on the calculated mismatch time, and the positioning process control unit 37 subtracts the provisional clock error calculated by the provisional clock error calculation unit 36 from the difference in arrival time of radio waves. A corrected arrival time difference of radio waves is obtained and output to the provisional positioning unit 34, and a series of positioning processes are completed according to the determination criteria, and the target provisional position and provisional clock error obtained in each process are determined as the final target The position and clock error are output, or a series of positioning processes are controlled to be continued again. Therefore, it is possible to correct the clock error between the sensors in the positioning device, and the same effect as in the first embodiment can be obtained.

In the first embodiment and the second embodiment, the case where the sensor is fixed has been described as an example. However, even when the sensor moves, if the position is known, the clock error between the target position and the sensor is calculated. can do.
In the first embodiment and the second embodiment, the method of calculating the target position by moving a single target whose position is desired to be known as time passes and observing the target multiple times has been described. However, a feature of the present invention is that the radio wave from the target at different positions is observed, and the clock error between the target position and the sensor is calculated based on the arrival time difference obtained therefrom. Therefore, when there are multiple targets at different positions, radio waves from each target are received once by each sensor, and based on the arrival time difference of each target obtained therefrom, the clock between each target position and the sensor is It is also possible to calculate the error.
Further, although a method using radio waves has been described, the present method can be applied even when used for sound waves or light waves regardless of the radio waves. Furthermore, although the case where the position of the target whose position is to be known is assumed to be three-dimensional has been described, even in the case of two dimensions, the altitude direction can be calculated by using conditions such as the presence of the target on the surface of the ground. . Furthermore, the functions of the positioning unit of the present invention described above can be executed by operating the CPU based on a software program.

It is a block diagram which shows the function structure of the positioning apparatus by Embodiment 1 of this invention. It is a block diagram which shows the other function structure of the positioning part which concerns on Embodiment 1 of this invention. It is a block diagram which shows the function structure of the positioning apparatus by Embodiment 2 of this invention. It is a block diagram which shows the structural example of the temporary clock error calculation part which concerns on Embodiment 2 of this invention. It is a block diagram which shows the other structural example of the temporary clock error calculation part which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structural example of the positioning process control part which concerns on Embodiment 2 of this invention. It is a block diagram which shows the other structural example of the positioning process control part which concerns on Embodiment 2 of this invention.

Explanation of symbols

1 ₁ to 1 _N sensor, 2 arrival time difference calculation unit, 3 positioning unit, 31 collective positioning unit, 32 motion model setting unit, 33 motion model positioning unit, 34 provisional positioning unit, 35 mismatch time calculation unit, 36 provisional clock error calculation Unit, 37 positioning processing control unit, 361 average processing unit, 362 weighting processing unit, 371 processing number counting unit, 372 residual processing unit.

Claims (17)

In a positioning device that receives radio waves radiated or reflected from a target by a plurality of sensors and calculates the position of the target based on the arrival time difference of the received radio waves,
An arrival time difference calculation unit for calculating an arrival time difference of radio waves received by each sensor multiple times;
A positioning apparatus comprising: a positioning unit that calculates a clock error between sensors and a target position at each time when the radio wave is received based on the calculated arrival time difference of radio waves between the sensors.   The positioning unit calculates the equation that the distance obtained by subtracting the clock error between sensors from the difference in arrival time of radio waves between sensors and the speed of radio waves is equal to the difference in radio wave propagation distance. The system according to claim 1, further comprising: a batch positioning unit that is created for each reception time and calculates a target position at each time at which the clock error between the sensors and the radio wave are received by combining these equations. Positioning device. The positioning unit
An exercise model setting unit for setting a target exercise model in advance;
A set motion model is set to the equation that the distance obtained by multiplying the time difference between each sensor by the time difference between each sensor and the time difference between the sensors is equal to the difference in the propagation distance. A motion model positioning unit is provided for calculating a clock error between sensors and a target position by generating these equations at the reception time of each radio wave corresponding to the above and combining these equations. Positioning device. The positioning unit
Create an equation for each radio wave reception time that the distance obtained by multiplying the corrected arrival time difference of the radio wave between the input sensors by the radio wave velocity is equal to the difference in the radio wave propagation distance. A temporary positioning unit that calculates the temporary position of the target at each time by
A time difference obtained by dividing the difference between the target temporary position and the distance of each sensor by the speed of the radio wave, and subtracting the time difference between the arrival times of the radio waves between the sensors to calculate a mismatch time at each time; ,
A provisional clock error calculation unit for calculating a provisional clock error between the sensors based on the calculated mismatch time;
The provisional clock error calculated by the provisional clock error calculation unit is subtracted from the arrival time difference of the radio wave to obtain a corrected arrival time difference of the radio wave and output to the provisional positioning unit, and according to the determination criterion, the provisional positioning unit, the mismatch A series of positioning processes by the time calculation unit and the provisional clock error calculation unit are completed, and the target provisional position and provisional clock error obtained in each process are output as the final target position and clock error, or The positioning apparatus according to claim 1, further comprising a positioning process control unit configured to control the series of positioning processes to be continued again.   5. The positioning device according to claim 4, wherein the provisional positioning unit creates an equation using a difference in arrival times of radio waves between sensors when there is no difference in corrected arrival times of input radio waves.   5. The positioning device according to claim 4, wherein the provisional clock error calculation unit includes an average processing unit that calculates an average value of mismatch times calculated by the mismatch time calculation unit as a provisional clock error between sensors.   The provisional clock error calculation unit includes a weighting processing unit that calculates a provisional clock error between sensors by weighting the mismatch time calculated by the mismatch time calculation unit using a weighting coefficient calculated by a predetermined method. The positioning device according to claim 4.   The positioning process control unit counts the number of executions of a series of positioning processes, and determines that the series of positioning processes is completed when the count number reaches a predetermined count value. 8. The processing number counting unit according to claim 4, further comprising a processing number counting unit that determines that the series of positioning processes is to be continued again when the count value is not reached. 9. Positioning device.   The positioning processing control unit is configured to obtain a residual between the provisional position of the target obtained by the provisional positioning unit in the previous process and the provisional position of the target obtained in the current process and / or the provisional clock error obtained in the previous process. When the residual of the provisional clock error obtained in the current process is smaller than a predetermined value, it is determined that the series of positioning processes is completed, and when the residual is larger than a predetermined value, The positioning device according to any one of claims 4 to 7, further comprising a residual processing unit that determines that a series of positioning processing is continuously performed again. In a positioning device that receives radio waves radiated or reflected from a target by a plurality of sensors and calculates the position of the target based on the arrival time difference of the received radio waves,
An arrival time difference calculation unit for calculating arrival time difference of radio waves from a plurality of targets received by each sensor;
A positioning apparatus comprising a positioning unit that calculates a clock error between sensors and each target position based on a difference in arrival time of radio waves between the sensors.   The positioning unit calculates an equality for each target that the distance obtained by multiplying the time difference of the radio wave between each sensor by the time of subtracting the clock error between each sensor and the speed of the radio wave is equal to the difference in the radio wave propagation distance. The positioning device according to claim 10, further comprising: a collective positioning unit configured to calculate a clock error between sensors and a position of each target by combining these formulas. The positioning unit
Create an equation for each target that the distance obtained by multiplying the corrected arrival time difference of the radio wave between the input sensors by the velocity of the radio wave is equal to the difference in the propagation distance of the radio wave, and make these equations simultaneous A provisional positioning unit that calculates the provisional position of each target,
A mismatch time calculation unit that subtracts the time obtained by dividing the difference between the provisional position of each target and the distance of each sensor by the velocity of the radio wave from the arrival time difference of the radio wave between each sensor and calculates it as the mismatch time for each target When,
A provisional clock error calculation unit for calculating a provisional clock error between the sensors based on the calculated mismatch time;
The provisional clock error calculated by the provisional clock error calculation unit is subtracted from the arrival time difference of the radio wave to obtain a corrected arrival time difference of the radio wave and output to the provisional positioning unit, and according to the determination criterion, the provisional positioning unit, the mismatch Whether a series of positioning processes by the time calculation unit and the provisional clock error calculation unit are completed, and the provisional position and provisional clock error of each target obtained in each processing are output as the final position and clock error of each target The positioning apparatus according to claim 10, further comprising a positioning processing control unit that performs control so that the series of positioning processing is continuously performed again.   The positioning device according to claim 12, wherein the provisional positioning unit creates an equation using a difference in arrival times of radio waves between sensors when there is no difference in corrected arrival times of input radio waves.   13. The positioning device according to claim 12, wherein the provisional clock error calculation unit includes an average processing unit that calculates an average value of the mismatch times calculated by the mismatch time calculation unit as a provisional clock error between sensors.   The provisional clock error calculation unit includes a weighting processing unit that calculates a provisional clock error between sensors by weighting the mismatch time calculated by the mismatch time calculation unit using a weighting coefficient calculated by a predetermined method. The positioning device according to claim 12.   The positioning process control unit counts the number of executions of a series of positioning processes, and determines that the series of positioning processes is completed when the count number reaches a predetermined count value. 16. The processing number counting unit for determining that the series of positioning processes is to be continued again when the count value is not reached. Positioning device. The positioning processing control unit determines the residual between the provisional position of each target obtained by the provisional positioning unit in the previous processing and the provisional position of each target obtained by the current processing and / or the provisional obtained by the previous processing. When the residual between the clock error and the provisional clock error obtained by the current process is smaller than a predetermined value, it is determined that the series of positioning processes is completed, and when the residual is larger than the predetermined value. The positioning apparatus according to claim 12, further comprising a residual processing unit that determines that the series of positioning processes is continuously performed again.

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