JP2007192573A - Target positioning device - Google Patents

Abstract

[PROBLEMS] To provide a low-speed signal processing and high resolution in a narrow receiver band, which does not require time synchronization between a transmitting station and a receiving station, and is composed of a small receiving station having a small-diameter antenna, and is flexible in operation. And provide a low-cost target positioning device.
In a target positioning apparatus, a transmitting station radiates a two-frequency CW radio wave, and three or more receiving stations directly mix a direct wave or a target reflected wave with a local signal similar to the two-frequency CW radio wave. Find the difference signal or target reflection difference signal, calculate the direct wave frequency that maximizes the output of the direct difference signal, calculate the target reflected wave frequency that maximizes the output of the target reflection difference signal, and calculate the direct wave frequency And the target position / speed estimator calculates the target three-dimensional position coordinates from the distance sum and the relative speed sum. A three-dimensional relative velocity component is estimated.
[Selection] Figure 1

Description

  The present invention relates to a target positioning device 1 in which a transmitting antenna 7 and a receiving antenna 8 are installed at different points and measures the position of an object of a target 20.

In the bistatic radar, the transmitting antenna 7 and the receiving antenna 8 are installed at different points, and the position of the object of the target 20 is measured. Since the time between the transmitting station 2 and the receiving station 3 must be synchronized in order to measure the distance from the target 20 object, a pulse for time synchronization using a Loran (Long Range Navigation) radio wave is transmitted. A method of generating and transmitting transmission pulse information indicating a transmission pulse period, time, and phase is employed (see, for example, Patent Document 1 and Patent Document 2).
In addition, time synchronization between the transmitting station 2 and the receiving station 3 is not performed, and a plurality of receiving stations 3 are provided, and the time difference of the target 20 reflected pulse is obtained by correlation processing between the direct wave and the target reflected wave. The position of the target 20 is specified (for example, refer to Patent Document 3).

JP-A-7-140124 JP 2003-156557 A JP-A-6-148318

However, in order to synchronize the time between the transmitting station and the receiving station, a synchronization pulser and transmission pulse information are required, and in order to obtain high distance accuracy, a wideband receiving system and high-speed signal processing are required. . In addition, there is a problem that a large-scale expensive antenna with a large aperture diameter is required to measure the angle with high accuracy in the receiving system.
In addition, in order to obtain the time difference between the direct wave pulse and the target reflected pulse with high accuracy at the receiving station, there is a problem that high-speed correlation processing with a broadband receiver is necessary and the device scale becomes large. In addition, there is a problem that it is impossible to measure the relative speed with high accuracy using the Doppler frequency.

  The object of the present invention is a small receiver station having a low-speed signal processing and high resolution in a narrow receiver band, no need for time synchronization between the transmitter station and the receiver station, and a small-diameter antenna, It is to provide a target positioning device that is flexible in operation and low in cost.

  The target positioning apparatus according to the present invention includes a transmitting station that radiates radio waves, three or more receiving stations that receive radio waves that arrive directly or after being reflected by a target object, and a target position and velocity based on the received radio waves. In the target positioning apparatus including the target position / speed estimator for estimating the transmission frequency, the transmitting station modulates the radio wave with the transmission two-frequency CW signal and the transmission two-frequency CW signal generator that generates the transmission two-frequency CW signal. A transmission signal converter, and the reception station receives a reception two-frequency CW signal generator that generates a local signal having a sweep slope and sweep time similar to those of the two-frequency CW, and a radio wave directly received from the transmission station. Or a reception signal for directly obtaining a difference signal or a target reflection difference signal by mixing a radio wave received after being reflected by a target and a local signal from the reception two-frequency CW signal generator 9 A converter, a direct wave frequency analyzing means for calculating a direct wave frequency at which the output of the direct difference signal is maximized, and a target reflected wave frequency analysis for calculating a target reflected wave frequency at which the output of the target reflected difference signal is maximized. Means for estimating a sum of distances and a relative speed sum between the transmitting station and the receiving station based on the direct wave frequency and the target reflected wave frequency, and the target position. The speed estimator estimates the target three-dimensional position coordinate and the three-dimensional relative speed component from the distance sum and the relative speed sum input from the receiving station.

  The effect of the target positioning apparatus according to the present invention is that it uses a two-frequency CW, does not need to synchronize the time of the receiving station with the time of the transmitting station, and does not require a synchronization pulser or transmission pulse information. Even with low-speed signal processing, high-accuracy position resolution can be achieved, and the mobile station can be made small and mobile, ensuring operational flexibility. In addition, since the two-frequency CW is used, the relative speed can be measured with high accuracy using the Doppler phenomenon.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a target positioning apparatus according to Embodiment 1 of the present invention. FIG. 2 is a diagram illustrating the positions of the transmitting station, the receiving station, and the target on the XY coordinate plane. FIG. 3 is a diagram illustrating a change in the frequency of the two-frequency CW signal at the transmitting station and the receiving station.
A target positioning apparatus 1 according to Embodiment 1 of the present invention includes one transmitting station 2, three receiving stations 3a, 3b, 3c and a target position / speed estimator 4 as shown in FIG. The sum of distances and the sum of relative velocities obtained in each of the receiving stations 3a to 3c are sent to the target position / speed estimator 4 using a general communication means. The target positioning device 1 according to the first embodiment includes three receiving stations 3, but may include four or more receiving stations 3.

The transmitting station 2, the receiving stations 3a to 3c and the target 20 are arranged as shown in FIG. When the coordinates of the transmitting station 2 are placed at the origin of the XYZ coordinate system, the position vectors of the receiving stations 3a to 3c are _Xn . n is a number for identifying the receiving stations 3a to 3c. Since three receiving stations 3a to 3c are provided, n = 1, 2, and 3. This position vector _Xn is known. The position vector X of the target 20 is an unknown value obtained by the target positioning device 1.
In FIG. 2, R ₀ is the distance between the transmitting station 2 and the target 20, R _n is the distance between the target 20 and the receiving station 3 with the identification number n, and R _0n is the receiving position with the transmitting station 2 and the identification number n. This is the distance between stations 3.
V ₀ is the relative speed between the transmitting station 2 and the target 20, v _n is the relative speed between the target 20 and the receiving station 3 with the identification number n, and v _0n is the receiving station with the transmitting station 2 and the identification number n. 3 relative speed.

As shown in FIG. 1, the transmitting station 2 modulates radio waves in accordance with a transmission 2-frequency CW signal generator 5 that generates a transmission 2-frequency CW signal and a transmission 2-frequency CW signal input from the transmission 2-frequency CW signal generator 5. A transmission signal converter 6 for transmitting, and a transmission antenna 7 for radiating radio waves into the air.
The transmission two-frequency CW signal generator 5 generates a transmission two-frequency CW signal that specifies the frequency of frequency modulation processing performed in the transmission signal converter 6. As shown in FIG. 3, the transmission two-frequency CW signal is alternately switched between the frequency f ₁ and the frequency f ₂ for each frequency switching period T _CC . In the target positioning apparatus 1 according to the present invention, in order to reduce the phase rotation of the Doppler shift depending on the transmission time difference, the frequencies f ₁ and f ₂ are switched at high speed by time division for each frequency switching period T _CC . .
The transmission signal converter 6 modulates the signal into a continuous wave having a frequency specified by the transmission two-cycle CW signal and outputs the modulated signal to the transmission antenna 7. That is, the frequency switching period _{T CC,} the frequency of the radio wave transmitted is the frequency _{f 1} or frequency _{f 2.} The radio Tx _i emitted is represented by the formula (1). i is a number for identifying the frequency f ₁ or the frequency f ₂ and is 1 or 2. φ _i is an arbitrary initial phase of the radio wave of each frequency at time t = 0. In order to facilitate understanding of the explanation, the envelope 1 has a constant amplitude.

  As shown in FIG. 1, each receiving station 3 includes a receiving antenna 8 that receives radio waves that propagate through the air, a reception 2-frequency CW signal generator 9 that generates a local signal based on the reception 2-frequency CW signal, A local signal is mixed with a received radio wave, a sum signal of frequencies is removed by a low-pass filter, a received signal converter 10 that generates a difference signal, and the difference signal is processed to estimate a distance sum and a relative velocity sum. A CW signal processor 11 is provided.

The radio wave radiated from the transmitting antenna 7 into the air reaches the receiving antenna 8 directly or after being reflected by the object of the target 20. In the following description, radio waves that arrive after being reflected by the object of the target 20 are referred to as target reflected waves, and radio waves that arrive directly are referred to as direct waves.
The target reflected wave Rx _{1, n} having the frequency f ₁ is expressed by Expression (2). Further, the target return _{Rx 2, n} of the frequency _{f 2} is expressed by Equation (3). τ ₀ is a radio wave propagation time between the transmission station 2 and the target 20 at time t = 0, and is expressed by Expression (4) when the distance R ₀ between the transmission station 2 and the target 20 is used. τ _n is the propagation time of the radio wave between the target 20 and the receiving station 3 with the identification number n at time t = 0, and using the distance R _n between the target 20 and the receiving station 3 with the identification number n, the equation (5 ). v ₀ is the relative speed between the transmitting station 2 and the target 20 at time t = 0, and v _n is the relative speed between the target 20 and the receiving station 3 with the identification number n at time t = 0. c is the speed of light.

Further, the direct wave Rx0 _{i, n} is expressed by Expression (6). Also, ζ _i is obtained from equation (7). Note that the direct wave is distinguished from the target reflected wave by time division and measuring when there is no target 20, or by measuring a gain difference due to antenna beam scanning. Even when the observation is performed simultaneously, the target reflected wave and the direct wave can be separated by making the relative speed between the transmitting station 2 and the receiving station 3 known to some extent (for example, both are stationary). In the following description, it is assumed that they are received separately.

The reception two-frequency CW signal generator 9 generates a reception two-frequency CW signal that generates a local signal for mixing the received radio wave in the reception signal converter 10, and uses the reception two-frequency CW signal to generate a local signal. It is generated and output to the received signal converter 10. As shown in FIG. 3, the reception 2-frequency CW signal is alternately switched between the frequency f ₁ and the frequency f ₂ for each frequency switching period T _CC as in the case of the transmission 2-frequency CW signal. However, there is a time lag between the transmitting station 2 and the receiving station 3.
The local signal L _{i, n} generated by the reception two-frequency CW signal generator 9 is expressed by Expression (8). Note that Φ _{i, n} is obtained from Equation (9) using the phase error δθ _{i, n} resulting from the time error of the two-frequency CW signal between each receiving station 3 and the transmitting station 2.

The reception signal converter 10 mixes the target reflected wave Rx _{i, n} with the local signal L _{i, n} , passes through the low-pass filter, removes the frequency sum signal, and obtains the target reflected difference signal B _{i, n.} . The target reflection difference signal B _{i, n} is expressed by Expression (10). Incidentally, the speed v _0, v _n as compared with the speed of light is assumed to be sufficiently small.
Further, the direct wave Rx0 _{i, n} is mixed with the local signal L _{i, n} , passes through the low-pass filter, the frequency sum signal is removed, and the direct difference signal B0 _{i, n} is obtained. The direct difference signal B0 _{i, n} is expressed by equation (11).

As shown in FIG. 1, the two-frequency CW signal processor 11 includes target reflected wave frequency analysis means 14, direct wave frequency analysis means 15, and distance sum speed sum estimation means 16.
The target reflected wave frequency analyzing means 14 uses the data of the target reflected difference signals B _{i, n} obtained by sampling M intervals T _C at a sampling interval T _S twice the frequency switching period T _CC shown in FIG. Discrete Fourier transform is performed to obtain an output F _{i, n} represented by Expression (12). Then, the amplitude | F _{i, n} | of the output F _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to p _{i, n} , respectively. The frequency f _{i, n} (hat) for this frequency number p _{i, n} is expressed by equation (13). Here, the difference (f ₂ −f ₁ ) is practically very small with respect to the transmission frequency f (for example, the average value of f ₁ and f ₂ ), and the frequency number p _{1, n} and the frequency number p _{2, n} are is equally frequency number _{p n.}

Direct wave frequency analyzing means 15, a discrete Fourier using twice the sampling interval T _S directly difference signal between the period T _C and the M sampled at B0 _{i, n} of the data of the frequency switching period T _CC shown in FIG. 3 The output F0 _{i, n} represented by the equation (14) is obtained by conversion. Then, the amplitude | F0 _{i, n} | of the output F0 _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to q _{i, n} , respectively. The frequency f0 _{i, n} (hat) at the time of this frequency number q _{i, n} is expressed by equation (15). Note that the frequency number q _{1, n} and the frequency number q _{2, n} are equal and are set to the frequency number q _n .

The distance sum speed sum estimating means 16 obtains the sum ξ _n (hat) of the distance between the transmitting station 2 and the target 20 and between the target 20 and each receiving station 3 from the equation (16). Note that arg represents an operation for obtaining a phase.
In the equation (16), the frequencies f ₁ and f ₂ are set values, and outputs F _{2, n} (p _n ), F _{1, n} (p _n ), F 0 _{2, n} (q _n ), F 0 _{1, n} (Q _n ) is obtained by discrete Fourier transform. Since the distance R _0n between the transmitting station 2 and each receiving station 3 is known, the time delay τ _0n is known, and the distance sum ξ _n (hat) is obtained from the equation (16).

The distance sum rate sum estimator 16 uses the frequency number p _n detected by the target return frequency analyzing means 14, the transmitting station 2 and the target 20 and the target 20 and the receiver 3 at each receiver 3 A relative speed sum V _n (hat) is obtained from the equation (17).
Further, the distance sum speed sum estimation means 16 uses the frequency number q _n detected by the direct wave frequency analysis means 15, and the relative speed V _0n between each receiving station 3 and the transmitting station 2 in each receiving station 3 ( Hat) is obtained from equation (18).

The target position / speed estimator 4 estimates the three-dimensional coordinates and the three-dimensional relative speed component of the target 20 according to the following procedure.
Since the position vector of the known transmitting station 2, the position vector of each known receiving station 3, and the position vector of the unknown target 20 to be estimated are X ₀ , X _n , and X, respectively, the distance sum of Expression (16) By using ξ _n , the relational expression of Expression (19) is established.
Then, the estimated value X (hat) of the position vector X of the target 20 is obtained by using general sums such as a conjugate gradient method, a quasi-Newton method, and a Levenberg-Marquardt method using the distance sum ξ _n (hat) at the three receiving stations 3. It is obtained using a typical nonlinear method.
If the relative velocity vector of the target 20 is V, the linear equation of equation (17) can be rewritten into equation (20).
Then, the estimated value V (hat) of the relative velocity vector V of the target 20 is obtained by using an inverse matrix or a general inverse matrix using the relative velocity sum V _n (hat) and estimated value X (hat) at the three receiving stations 3. It is calculated using.

  Such a target positioning device 1 uses two-frequency CW as a radio wave and includes three or more receiving stations. The target positioning device 1 does not need to synchronize the time of the receiving station 3 with the time of the transmitting station 2, and can synchronize a pulsar or transmission. Since pulse information is not required, high-precision position resolution can be realized even in a narrow-band receiving system and a low-speed signal processing system, and the receiving station 3 can be made small and movable, thereby ensuring operational flexibility. In addition, since the two-frequency CW is used, the relative speed can be estimated with high accuracy using the Doppler phenomenon.

Note that when the transmitting station 2 has a receiving function as well as a transmitting function, one of the three receiving stations 3 can be imposed on the transmitting station 2, so two receiving stations 3 are sufficient.
Further, when the two-dimensional estimation on the horizontal plane coordinates is performed for estimating the position of the target 20 and the relative speed, two receiving stations 3 may be used.
When the number of receiving stations 3 is two, the target position / velocity estimator 4 measures the position of the target 20 as the intersection of the spheroids by using the two distance sums ξ _n obtained by the equation (16). Is also possible. That is, the target 20 exists at the intersection of the two spheroids of the distance sum ξ _n with the transmitting station 2 and the receiving station 3 as the focal points, but by adding a constraint condition such as making the horizontal plane coordinate positive, The target 20 position can be estimated by selecting an appropriate solution as the target 20 position at the intersection of the two spheroids.

  In addition, a 2-frequency pulse obtained by pulsing the 2-frequency CW (also referred to as 2-frequency ICW (also referred to as 2-frequency interrupted CW)), and by using distance gating, further narrow band, separation of direct wave and target reflected wave, multi-target Separation, avoidance of short distance clutter, etc.

Embodiment 2. FIG.
FIG. 4 is a configuration diagram of a target positioning apparatus according to Embodiment 2 of the present invention. FIG. 5 is a diagram illustrating the positions of the transmitting station, the receiving station, and the target on the XY coordinate plane.
Since the target positioning device 1B according to the second embodiment of the present invention is different in the number of stations of the target positioning device 1 according to the first embodiment, the transmitting station 2 and the receiving station 3B, the other points are the same. The same reference numerals are attached to these parts, and the description is omitted.
As shown in FIG. 4, the target positioning apparatus 1B according to the second embodiment includes three transmitting stations 2a to 2c and one receiving station 3B. Although the target positioning device 1B according to the second embodiment includes the three transmission stations 2, the same effect can be obtained even if four or more transmission stations 2 are provided.

The transmitting stations 2a to 2c, the receiving station 3B, and the target 20 are arranged as shown in FIG. When the coordinates of the receiving station 3B are placed at the origin of the XYZ coordinate system, the position vectors of the transmitting stations 2a to 2c are _Xn . n is a number for identifying the transmission stations 2a to 2c. Since three transmission stations 2a to 2c are provided, n = 1, 2, and 3. This position vector _Xn is known. The position vector X of the target 20 is an unknown value obtained by the target positioning device 1B.

  From each of the transmission stations 2a to 2c, the transmission is time-divided in order to separate the three target reflected waves. Note that two-frequency CW radio waves having different frequencies may be radiated for each of the transmission stations 2a to 2c, and the reception signal converter 10 of the reception station 3B may mix the local signals of the two frequencies CW.

Assuming that the phase error δθ _{i, n} caused by the time error of the two-frequency CW signal between each of the transmitting stations 2a to 2c and the receiving station 3B, the target reflection difference signal B _{i, n} is expressed in the same manner as in equation (10). The
Then, the target reflected wave frequency analyzing means 14 is similar to the first embodiment, and the target reflected difference signal B _i obtained by sampling M during the interval T _C at the sampling interval T _S that is twice the frequency switching period T _{CC. , N} is used to perform a discrete Fourier transform to obtain an output F _{i, n} represented by equation (12). Then, the amplitude | F _{i, n} | of the output F _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to p _{i, n} , respectively. The frequency f _{i, n} (hat) for this frequency number p _{i, n} is expressed by equation (13).

Similarly to the first embodiment, the direct wave frequency analyzing means 15 directly samples the difference signal B0 _{i, n} obtained by sampling M intervals T _C at a sampling interval T _S that is twice the frequency switching period T _CC. The output F0 _{i, n} represented by the equation (14) is obtained by performing a discrete Fourier transform using the above data. Then, the amplitude | F0 _{i, n} | of the output F0 _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to q _{i, n} , respectively. The frequency f0 _{i, n} (hat) at the time of this frequency number q _{i, n} is expressed by equation (15).

Using the frequency f _{i, n} (hat) and the frequency f0 _{i, n} (hat) obtained in this manner, the estimated value X (hat) of the position vector of the target 20, relative to the target 20, as in the first embodiment. The estimated value V (hat) of the velocity vector can be estimated.

If such a target positioning apparatus 1B includes three or more transmitting stations 2, it is not necessary to synchronize the time of the receiving station 3 with the time of the transmitting station 2 as in the first embodiment, and a synchronous pulser or transmission Since pulse information is not required, high-precision position resolution can be realized even in a narrow-band receiving system and a low-speed signal processing system, and the receiving station 3 can be made small and movable, thereby ensuring operational flexibility.
Even if the number of transmitting stations is 2, the target 20 position coordinates can be estimated by obtaining the intersection of the spheroids from the two distance sums ξ _n .

Embodiment 3 FIG.
FIG. 6 is a block diagram of a target positioning apparatus according to Embodiment 3 of the present invention. FIG. 7 is a diagram showing the positions of the transmitting station, the receiving station, and the target on the XY coordinate plane.
As shown in FIG. 6, the target positioning device 1C according to the third embodiment of the present invention receives signals common to the reception signal converters 10 of the three receiving stations 3a to 3c of the target positioning device 1 according to the first embodiment. Since the local signal is supplied from the two-frequency CW signal generator 9 and the two-frequency CW signal processor 11C is different along with it, the other parts are the same. To do.
In the two-frequency CW signal processor 11C according to the third embodiment, the direct wave frequency analyzing means 15 is deleted from the two-frequency CW signal processor 11 according to the first embodiment.

The target positioning apparatus 1C according to the third embodiment receives only the target reflected wave as shown in FIG.
Each of the receiving stations 3Ca to 3Cc has a cable 18 while adjusting the phase of the received 2-frequency CW signal from the received 2-frequency CW signal generator 9 to a constant value by correcting the delay due to the difference in cable length. It is connected.

Since the received two-frequency CW signal according to the third embodiment has the same phase between the receiving stations 3Ca to 3Cc, the phase error δθ _{i, n} of the transmitting station 2 and each of the receiving stations 3Ca to 3Cc is equal, and the phase The error is δθ _i . Therefore, the target reflection difference signal Bi, n after being mixed by the reception signal converter 10 in each of the reception stations 3Ca to 3Cc is expressed by Expression (21).

The target reflected wave frequency analyzing means 14C performs discrete Fourier transform using data of the target reflected difference signal B _{i, n} obtained by sampling M intervals T _C at a sampling interval T _S that is twice the frequency switching period T _CC. The output F _{i, n} represented by the equation (12) is obtained. Then, the amplitude | F _{i, n} | of the output F _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to p _{i, n} , respectively. The frequency f _{i, n} (hat) for this frequency number p _{i, n} is expressed by equation (13). Here, the difference (f ₂ −f ₁ ) is practically very small with respect to the transmission frequency f (for example, the average value of f ₁ and f ₂ ), and the frequency number p _{1, n} and the frequency number p _{2, n} are is equally frequency number _{p n.}
Distance sum rate sum estimating means 16C is a phase alpha _{i, n} of the detected frequency number _{p n} (hat), determined from the equation (22). Phase difference between the phase alpha _{2, n} (hat) phase alpha _{1, n} (hat) and frequency number _{p n} of the frequency _{f 2} of the frequency number _{p n} of the frequency _{f 1,} the relation of formula (23) holds.

Then, the distance sum speed sum estimating means 16C uses the measured phase difference to calculate the sum of the distances ξ _n (hat) between the transmitting station 2 and the target 20 and between the target 20 and each of the receiving stations 3Ca to 3Cc from Expression (24). ) Note that, unlike the equation (16), the equation (24) includes a fixed term {− (1 / 2π) × (ζ ₂ −ζ ₁ + δθ ₂ −δθ ₁ ) / (f ₂ −f ₁ )}. .
Further, the distance sum speed sum estimating means 16C obtains the relative speed sum V _n (hat) from the equation (25).

The target position / speed estimator 4C estimates the three-dimensional coordinates and the three-dimensional relative speed component of the target 20 according to the following procedure.
If the position vector of the known transmitting station 2, the position vector of each known receiving station 3, and the position vector of the unknown target 20 to be estimated are X ₀ , X _n , and X, respectively, the distance sum ξ in equation (24) By using _n , Expressions (26) to (28) that can eliminate the phase error are established.
Then, the estimated value X (hat) of the position vector X of the target 20 is calculated using the conjugate gradient method, the quasi-Newton method, the Levenberg-Marquardt method, etc. using the distance sum ξ _n (hat) at the three receiving stations 3Ca to 3Cc. It is obtained using a general non-linear method.

Further, when the relative velocity vector of the target 20 is V, the linear equation of Expression (25) can be rewritten into Expression (29).
Then, the estimated value V (hat) of the relative velocity vector V of the target 20 is obtained by using an inverse matrix or a general inverse matrix using the relative velocity sum V _n (hat) and estimated value X (hat) at the three receiving stations 3. It is calculated using.

Such a target positioning apparatus 1C does not need to measure a direct wave because there is no phase error difference between the received two-frequency CW signals to the receiving stations 3Ca to 3Cc.
The same applies to a configuration in which a plurality of reception two-frequency CW signals are provided and they are time-synchronized.

Embodiment 4 FIG.
FIG. 8 is a block diagram of a target positioning apparatus according to Embodiment 4 of the present invention. FIG. 9 is a diagram illustrating the positions of the transmitting station, the receiving station, and the target on the XY coordinate plane.
The target positioning device 1D according to the fourth embodiment of the present invention is supplied with the target positioning device 1B according to the second embodiment synchronized with the transmission two-frequency CW signal, and the two-frequency CW signal processor 11D is different accordingly. Since the rest is the same, the same reference numerals are given to the same parts and the description is omitted.
A target positioning apparatus 1D according to the fourth embodiment includes three transmitting stations 2Da to 2Dc and one receiving station 3D. Although the target positioning device 1D according to the fourth embodiment includes the three transmission stations 2Da to 2Dc, the same effect can be obtained even if the four or more transmission stations 2 are provided.
Each of the transmission stations 2Da to 2Dc is connected with a cable 18 while adjusting the phase of the transmission 2-frequency CW signal from one transmission 2-frequency CW signal generator 5 to a constant value by correcting a delay due to a difference in cable length. It is connected. Further, from each of the transmission stations 2Da to 2Dc, transmission is time-divided in order to separate the target reflected wave.

Since the transmission two-frequency CW signal according to the fourth embodiment has the same phase between the transmission stations 2Da to 2Dc, the phase errors δθ _{i, n} of the transmission stations 2Da to 2Dc and the reception station 3D are equal, and the phase The error is δθ _i . Accordingly, the target reflection difference signal B _{i, n} after being mixed by the reception signal converter 10 of the reception station 3D is expressed by Expression (21).

The target reflected wave frequency analyzing means 14D performs discrete Fourier transform using data of the target reflected difference signal B _{i, n} obtained by sampling M intervals T _C at a sampling interval T _S that is twice the frequency switching period T _CC. The output F _{i, n} represented by the equation (12) is obtained. Then, the amplitude | F _{i, n} | of the output F _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to p _{i, n} , respectively. The frequency f _{i, n} (hat) for this frequency number p _{i, n} is expressed by equation (13). Here, the difference (f ₂ −f ₁ ) is practically very small with respect to the transmission frequency f (for example, the average value of f ₁ and f ₂ ), and the frequency number p _{1, n} and the frequency number p _{2, n} are is equally frequency number _{p n.}

Distance sum rate sum estimating means 16D is a phase alpha _{i, n} of the detected frequency number _{p n} (hat), determined from the equation (22). Phase difference between the phase alpha _{2, n} (hat) phase alpha _{1, n} (hat) and frequency number _{p n} of the frequency _{f 2} of the frequency number _{p n} of the frequency _{f 1,} the relation of formula (23) holds.

Then, the distance sum speed sum estimation means 16D calculates the sum ξ _n (hat) of the distances between the transmitting stations 2 and the targets 20, and between the targets 20 and the receiving stations 3 from the equation (24) using the measured phase difference. Ask.
Further, the distance sum speed sum estimating means 16D obtains the relative speed sum V _n (hat) from the equation (25).

The target position / speed estimator 4D estimates the three-dimensional coordinates and the three-dimensional relative speed component of the target 20 according to the following procedure.
When the position vector of the known receiving station 3D, the position vector of each of the known transmitting stations 2Da to 2Dc, and the position vector of the unknown target 20 to be estimated are X ₀ , X _n , and X, respectively, the distance of Expression (24) By using the sum ξ _n , Expressions (26) to (28) that can eliminate the phase error are established.
Then, the estimated value X (hat) of the position vector X of the target 20 is calculated using the conjugate gradient method, the quasi-Newton method, the Levenberg-Marquardt method, etc. using the distance sum ξ _n (hat) from the three transmitting stations 2Da to 2Dc. It is obtained using a general non-linear method.

Further, when the relative velocity vector of the target 20 is V, the linear equation of Expression (25) can be rewritten into Expression (29).
Then, the estimated value V (hat) of the relative velocity vector V of the target 20 is obtained by using an inverse matrix or generality using the relative velocity sum V _n (hat) and the estimated value X (hat) at the three transmission stations 2Da to 2Dc. It is obtained using an inverse matrix.

Such a target positioning apparatus 1D does not need to measure a direct wave because there is no phase error difference between the transmission two-frequency CW signals to the transmission stations 2Da to 2Dc.
The same applies to a configuration in which a plurality of transmission two-frequency CW signals are provided and they are time-synchronized.

Embodiment 5 FIG.
FIG. 10 is a block diagram of a target positioning apparatus according to Embodiment 5 of the present invention. FIG. 11 is a diagram showing the positions of the target transmitting station and receiving station on the XY coordinate plane.
The target positioning apparatus 1E according to the fifth embodiment of the present invention includes one transmitting station 2, three receiving stations 3Ea, 3Eb, 3Ec and a target position / speed estimator 4E. Is estimated. The sum of distances and the sum of relative velocities obtained by the receiving stations 3Ea to 3Ec are sent to the target position / speed estimator 4E using communication means. Although the target positioning apparatus 1E according to the fifth embodiment includes the three receiving stations 3Ea to 3Ec, the same effect can be obtained by including four or more receiving stations.

In the target positioning apparatus 1E according to the fifth embodiment, the reception two-frequency CW signal is supplied from the common reception two-frequency CW signal generator 9 to the reception signal converters 10 of the three reception stations 3Ea to 3Ec. Each of the receiving stations 3Ea to 3Ec has a cable 18 while adjusting the phase of the received 2-frequency CW signal from one received 2-frequency CW signal generator 9 to a constant value by correcting the delay due to the difference in cable length. It is connected. Since the received two-frequency CW signal according to the fifth embodiment has the same phase between the receiving stations 3Ea to 3Ec, the phase error δθ _{i, n} between the transmitting station 2 and each of the receiving stations 3Ea to 3Ec is equal, and the phase The error is δθ _i .

Since the transmitting station 2 is the same as the transmitting station 2 according to the first embodiment, description thereof is omitted. The radio Tx _i emitted is represented by the formula (30). i represents the frequency f ₁ or the frequency f ₂ and is 1 or 2. φ _i is an arbitrary initial phase of the radio wave of each frequency at time t = 0. In order to make the explanation easy to understand, the envelope 1 has a constant amplitude.

  Each of the receiving stations 3Ea to 3Ec receives a radio wave that propagates through the air and receives a radio wave that arrives, mixes the received 2-frequency CW signal with the received radio wave, removes a sum signal of frequencies by a low-pass filter, and obtains a difference signal And a two-frequency CW signal processor 11E that processes the difference signal and estimates a sum of distances and a sum of relative velocities. The reception station 3Ea includes a reception 2-frequency CW signal generator 9 that generates a reception 2-frequency CW signal, and a cable 18 is connected to the reception signal converter 10.

The radio wave radiated from the transmitting antenna 7 into the air directly reaches the receiving antenna 8. In the following description, radio waves that reach directly are referred to as direct waves. The direct wave Rx0 _{i, n} is expressed by Expression (31). Note that τ _0n is a propagation time during which the radio wave propagates between the transmitting station and the receiving station, and the relational expression of the distance R _0n between the transmitting station and the receiving station and Expression (32) is established.

The reception 2 frequency CW signal generator 9 generates a reception 2 frequency CW signal for generating a local signal for mixing the received direct wave in the reception signal converter 10, and uses the reception 2 frequency CW signal to generate a local signal. And output to the received signal converter 10. Similarly to the transmission two-frequency CW signal, the frequency designation value of the reception two-frequency CW signal is alternately switched between the frequency f ₁ and the frequency f ₂ for each frequency switching period T _CC . However, there is a time lag between the transmitting station 2 and the receiving station 3.
The local signal L _{i, n} generated by the reception 2-frequency CW signal generator 9E is expressed by Expression (33). Note that Φ _{i, n} is obtained from Expression (34) using the phase error δθ _i resulting from the time error of the two-frequency CW signal between each receiving station 3 and the transmitting station 2.

The reception signal converter 10E mixes the direct wave Rx0 _{i, n} with the local signal L _{i, n} , passes through the low-pass filter, removes the frequency sum signal _{, and} obtains the direct difference signal B0 _{i, n} . The direct difference signal B0 _{i, n} is expressed by Expression (35).

The two-frequency CW signal processor 11E includes a direct wave frequency analysis unit 15 and a distance sum speed sum estimation unit 16.
The direct wave frequency analyzing means 15E performs discrete Fourier transform using the data of the direct difference signal B0 _{i, n} obtained by sampling M intervals T _C at a sampling interval T _S that is twice the frequency switching period T _CC. The output F0 _{i, n} represented by (36) is obtained. Then, the amplitude | F0 _{i, n} | of the output F0 _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to q _{i, n} , respectively. The frequency f0 _{i, n} (hat) for this frequency number q _{i, n} is expressed by equation (37). Note that the frequency number q _{1, n} and the frequency number q _{2, n} are equal and are set to the frequency number q _n .

The distance sum speed sum estimating means 16E obtains the phase α _{i, n} (hat) of the detected frequency number q _n from the equation (38). The phase difference between the phase α _{1, n} (hat) of the frequency number q _n of the frequency f ₁ and the phase α _{2, n} (hat) of the frequency number q _n of the frequency f ₂ has the relationship of Expression (39).
Then, the distance sum speed sum estimating means 16E calculates the sum ξ _n (hat) of the distance between the transmitting station 2 and the target 20 and between the target 20 and each receiving station 3 from the equation (40) using the measured phase difference. Ask.
Further, the distance sum speed sum estimating means 16E obtains the relative speed sum Vn (hat) from the equation (41).

The target position / speed estimator 4E estimates the three-dimensional coordinates and the three-dimensional relative speed component of the transmitting station 2 according to the following procedure.
Assuming that the position vector of the unknown transmitting station 2E to be estimated and the position vector of each known receiving station 3 are X and _Xn , respectively, the time error δt is eliminated by using the distance sum ξ _n of Equation (40). Thus, the relational expressions (42) to (44) are established.
Then, the estimated value X (hat) of the position vector X of the transmitting station 2 is calculated using the conjugate gradient method, the quasi-Newton method, the Levenberg-Marquardt, using the distance sum ξ _n (hat) at the three receiving stations 3Ea to 3Ec. It is obtained by using a general nonlinear method such as the method.

When the relative velocity vector of the transmitting station 2 is V, the relative velocity vector V satisfies the relational expression (45).
Then, the estimated value V (hat) of the relative velocity vector V of the transmitting station 2 is obtained by using the relative velocity sum V _n (hat) and the estimated value X (hat) at the three receiving stations 3Ea to 3Ec, It is obtained using a general inverse matrix.

  Such a target positioning apparatus 1E needs to synchronize the time of the receiving stations 3Ea to 3Ec with the time of the transmitting station 2 in the operation mode in which the target to be estimated is the transmitting station 2 as in the first embodiment. Since no synchronization pulser or transmission pulse information is required, high-accuracy position resolution can be realized even in a narrow-band reception system and a low-speed signal processing system, resulting in small and mobile reception stations 3Ea to 3Ec. , Ensure operational flexibility.

Embodiment 6 FIG.
FIG. 12 is a block diagram of a target positioning apparatus according to Embodiment 6 of the present invention. FIG. 13 is a diagram showing the positions of the target receiving station and transmitting station on the XY coordinate plane.
A target positioning apparatus 1F according to Embodiment 6 of the present invention includes three transmitting stations 2Fa to 2Fc, one receiving station 3F, and a target position / speed estimator 4F, and estimates the position and relative speed of the receiving station 3F. To do. The distance sum and the relative speed sum obtained at the receiving station 3F are sent to the target position / speed estimator 4F using the communication means. The target positioning apparatus 1F according to the sixth embodiment includes the three transmission stations 3Fa to 3Fc, but the same effect can be obtained even if four or more transmission stations are provided.

In the target positioning apparatus 1F according to the sixth embodiment, the transmission 2-frequency CW signal is supplied from the transmission 2-frequency CW signal generator 5 to the transmission signal converters 6 of the three transmission stations 2Fa to 2Fc. Each of the transmission stations 2Fa to 2Fc is connected with the cable 18 while adjusting the phase of the transmission 2-frequency CW signal from one transmission 2-frequency CW signal generator 5 to a constant value by correcting the delay due to the difference in the cable length. It is connected. Since the transmission two-frequency CW signal according to the sixth embodiment has the same phase between the transmission stations 2Fa to 2Fc, the phase errors δθ _{i, n} of the transmission stations 2Fa to 2Fc and the reception station 3F are equal, and the phase error δθ _i .

The reception 2 frequency CW signal generator 9 generates a reception 2 frequency CW signal for generating a local signal for mixing the received direct wave in the reception signal converter 10, and uses the reception 2 frequency CW signal to generate a local signal. And output to the received signal converter 10. Similarly to the transmission two-frequency CW signal, the frequency designation value of the reception two-frequency CW signal is alternately switched between the frequency f ₁ and the frequency f ₂ for each frequency switching period T _CC . However, there is a time lag between the transmitting station 2 and the receiving station 3.
The local signal L _{i, n} generated by the reception two-frequency CW signal generator 9 is expressed by Expression (33). In addition, (PHI) _i is calculated | required from Formula (34) using the phase error (delta) (theta) _i resulting from the time error of the 2 frequency CW signal between each transmitting station 2Fa-2Fc and the receiving station 3F.

The reception signal converter 10 mixes the direct wave Rx0 _{i, n} with the local signal L _{i, n} , passes through the low-pass filter, removes the frequency sum signal _{, and} obtains the direct difference signal B0 _{i, n} . The direct difference signal B0 _{i, n} is expressed by Expression (35).

Direct wave frequency analysis unit 15F of the formula and a discrete Fourier transform by using twice the sampling interval T _S directly difference signal between the period T _C and the M sampled at B0 _{i, n} of the data of the frequency switching period T _CC The output F0 _{i, n} represented by (36) is obtained. Then, the amplitude | F0 _{i, n} | of the output F0 _{i, n} is thresholded, and the frequency numbers k at which peaks are obtained are set to q _{i, n} , respectively. The frequency f0 _{i, n} (hat) for this frequency number q _{i, n} is expressed by equation (37). Note that the frequency number q _{1, n} and the frequency number q _{2, n} are equal and are set to the frequency number q _n .

The distance sum speed sum estimating means 16F calculates the phase α _{i, n} (hat) of the detected frequency number q _n from the equation (38). The phase difference between the phase α _{1, n} (hat) of the frequency number q _n of the frequency f ₁ and the phase α _{2, n} (hat) of the frequency number q _n of the frequency f ₂ has the relationship of Expression (39).
Then, the distance sum speed sum estimating means 16F uses the measured phase difference to calculate the sum ξ _n (hat) of the distances between the transmitting stations 2Fa to 2Fc, the target 20, and the target 20 and the receiving station 3 from the equation (40). )
Further, the distance sum speed sum estimating means 16F obtains the relative speed sum Vn (hat) from the equation (41).

The target position / speed estimator 4F estimates the three-dimensional coordinates and the three-dimensional relative speed component of the receiving station 3F according to the following procedure.
Unknown position vector and the known position vector of each transmitting station 2Fa~2Fc receiving station 3F estimation target, respectively X, When _{X n,} by using the distance sum xi] _n of formula (40), time error δt Is deleted, and the relational expressions (42) to (44) are established.
Then, the estimated value X (hat) of the position vector X of the receiving station 3F is obtained using the conjugate gradient method, quasi-Newton method, and Levenberg-Marquardt method using the distance sum ξ _n (hat) with the three transmitting stations 2Fa to 2Fc. It is calculated | required using general nonlinear methods, such as.

When the relative velocity vector of the receiving station 3F is V, the relative velocity vector V satisfies the relational expression (45).
Then, the estimated value V (hat) of the relative velocity vector V of the receiving station 3F is obtained by using the relative velocity sum V _n (hat) and the estimated value X (hat) at the three transmitting stations 2Fa to 2Fc, It is obtained using a general inverse matrix.

  Such a target positioning device 1F does not need to synchronize the time of the transmitting stations 2Fa to 2Fc with the time of the receiving station 3F even in an operation mode in which the target for estimating the position and velocity is the receiving station 3F. And transmission pulse information is not required, so it is possible to achieve high-precision position resolution even in narrow-band reception systems and low-speed signal processing systems. it can.

  It is also possible to use the target position estimation method in the case where the distance sum speed sum estimation means in the first to sixth embodiments is used and the angle measurement can be performed at the receiving station.

It is a block diagram of the target positioning apparatus concerning Embodiment 1 of this invention. It is a figure which shows the position on the XY coordinate plane of a transmitting station, a receiving station, and a target. It is a figure which shows the mode of a frequency change of the 2 frequency CW signal in a transmission station and a receiving station. It is a block diagram of the target positioning apparatus concerning Embodiment 2 of this invention. It is a figure which shows the position on the XY coordinate plane of a transmitting station, a receiving station, and a target. It is a block diagram of the target positioning apparatus concerning Embodiment 3 of this invention. It is a figure which shows the position on the XY coordinate plane of a transmitting station, a receiving station, and a target. It is a block diagram of the target positioning apparatus concerning Embodiment 4 of this invention. It is a figure which shows the position on the XY coordinate plane of a transmitting station, a receiving station, and a target. It is a block diagram of the target positioning apparatus concerning Embodiment 5 of this invention. It is a figure which shows the position on the XY coordinate plane of the transmission station and receiving station which are targets. It is a block diagram of the target positioning apparatus concerning Embodiment 6 of this invention. It is a figure which shows the position on the XY coordinate plane of the receiving station and transmitting station which are targets.

Explanation of symbols

  1 target positioning device, 2 transmitting station, 3 receiving station, 4 target position / speed estimator, 5 transmitting 2 frequency CW signal generator, 6 transmitting signal converter, 7 transmitting antenna, 8 receiving antenna, 9 receiving 2 frequency CW signal Generator, 10 Received signal converter, 11 2 frequency CW signal processor, 14 Target reflected wave frequency analyzing means, 15 Direct wave frequency analyzing means, 16 Distance sum speed sum estimating means, 18 Cable, 20 Target.

Claims (6)

Transmitting station that emits radio waves, three or more receiving stations that receive radio waves that arrive directly or after being reflected by the target object, and target position / speed estimation that estimates the target position and speed based on the received radio waves In the target positioning device comprising a device,
The transmitter station
A transmission 2 frequency CW signal generator for generating a transmission 2 frequency CW signal;
A transmission signal converter that modulates radio waves with the transmission two-frequency CW signal;
With
The receiving station is
A receiving two-frequency CW signal generator for generating a local signal having the same sweep slope and sweep time as the two-frequency CW;
The direct difference signal or the target reflection difference signal is obtained by mixing the radio wave directly received from the transmitting station or the radio wave received after being reflected by the target and the local signal from the reception two-frequency CW signal generator 9. A received signal converter;
Direct wave frequency analyzing means for calculating a direct wave frequency at which the output of the direct difference signal is maximized;
A target reflected wave frequency analyzing means for calculating a target reflected wave frequency at which the output of the target reflected difference signal is maximized;
Distance sum speed sum estimating means for estimating a distance sum and a relative speed sum between the transmitting station and the receiving station based on the direct wave frequency and the target reflected wave frequency;
With
The target position / speed estimator estimates a target three-dimensional position coordinate and a three-dimensional relative speed component from the distance sum and the relative speed sum input from the receiving station. apparatus. The reception 2-frequency CW signal generator of the receiving station generates a reception 2-frequency CW signal that is synchronized with the reception 2-frequency CW signal generators of the other reception stations,
The distance sum speed sum estimation means estimates a distance sum and a relative speed sum between the transmitting station and the receiving station based on a phase difference between two frequencies at the target reflected wave frequency. The target positioning device according to claim 1. The reception 2-frequency CW signal generator of the receiving station generates a reception 2-frequency CW signal that is synchronized with the reception 2-frequency CW signal generators of the other reception stations,
The distance sum speed sum estimating means estimates a distance sum and a relative speed sum between the transmitting station and the receiving station based on a phase difference between two frequencies at the direct wave frequency. Item 5. The target positioning device according to item 1. Three or more transmitting stations that radiate radio waves, a receiving station that receives radio waves that arrive directly or after being reflected by a target object, and a target position / speed estimate that estimates the target position and velocity based on the received radio waves In the target positioning device comprising a device,
The transmitter station
A transmission 2 frequency CW signal generator for generating a transmission 2 frequency CW signal;
A transmission signal converter that modulates radio waves with the transmission two-frequency CW signal;
With
The receiving station is
A receiving two-frequency CW signal generator for generating a local signal having the same sweep slope and sweep time as the two-frequency CW;
The direct difference signal or the target reflection difference signal is obtained by mixing the radio wave directly received from the transmitting station or the radio wave received after being reflected by the target and the local signal from the reception two-frequency CW signal generator 9. A received signal converter;
Direct wave frequency analyzing means for calculating a direct wave frequency at which the output of the direct difference signal is maximized;
A target reflected wave frequency analyzing means for calculating a target reflected wave frequency at which the output of the target reflected difference signal is maximized;
Distance sum speed sum estimating means for estimating a distance sum and a relative speed sum between the transmitting station and the receiving station based on the direct wave frequency and the target reflected wave frequency;
With
The target position / speed estimator estimates a target three-dimensional position coordinate and a three-dimensional relative speed component from the distance sum and the relative speed sum input from the receiving station. apparatus. The transmitting two-frequency CW signal generator of the transmitting station generates a transmitting two-frequency CW signal that is synchronized with the transmitting two-frequency CW signal generator of another transmitting station,
The distance sum speed sum estimation means estimates a distance sum and a relative speed sum between the transmitting station and the receiving station based on a phase difference between two frequencies at the target reflected wave frequency. The target positioning device according to claim 4. The transmitting two-frequency CW signal generator of the transmitting station generates a transmitting two-frequency CW signal that is synchronized with the transmitting two-frequency CW signal generator of another transmitting station,
The distance sum speed sum estimating means estimates a distance sum and a relative speed sum between the transmitting station and the receiving station based on a phase difference between two frequencies at the direct wave frequency. Item 5. The target positioning device according to item 4.

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