JP5496066B2 - Transceiver - Google Patents

Description

  The present invention relates to a transmission / reception apparatus that radiates radio waves, which are transmission signals, from a plurality of antennas, receives a radio wave reflected by a target, and performs signal processing on transmission / reception signals applied to a radar that detects the target.

As a conventional transmission / reception apparatus of this type, for example, there is one shown in “Hirata et al., Repetitive MIMO Beamforming for Radar, 2010 IEICE General Conference, B-2-42”. In the conventional transmitter / receiver, the received beamforming load obtained by reception is repeatedly used for the beamforming of transmission in response to the problem that the beamforming accuracy of transmission / reception decreases at low signal-to-noise ratio (S / N). As a result, the transmission beam power is gradually improved to calculate a beam forming load with high accuracy. However, since the optimum beam forming load generally has different amplitude values for each element antenna, it is necessary to perform amplitude control in the transmission beam forming, and it is difficult to realize H / W (HardWare). Moreover, it was necessary to repeat transmission several times before convergence.
Conventionally, MIMO (Multi Input Multi Output) radar (F. C. Robey et al., MIMO Radar Theory and Experimental Results, 2004 Asilomar Conference, vol. 1) that modulates each transmitting element and demodulates and separates the received signal for each transmitting element. , Pp300-304. In MIMO radar, by transmitting a different signal at the time of transmission, the transmission beam gain is not obtained compared to other beam forming devices, and it becomes a lower S / N environment, so it is adaptive to calculate the beam forming load from the received signal The beam formation is difficult and the radar detection has a low S / N. Therefore, many integration processes are required, and there is a problem that the amount of calculation increases.

Hirata et al., “Repetitive MIMO Beamforming for Radar”, 2010 IEICE General Conference, B-2-42. F. C. Robey et al., “MIMO Radar Theory and Experimental Results”, 2004 Asilomar Conference, vol. 1, pp300-304.

  In the conventional transmission / reception apparatus, amplitude control is required in the beam forming of transmission, and it is difficult to realize H / W, and there is a problem that it is necessary to repeat transmission several times before convergence. Further, the conventional MIMO radar has a problem that the transmission gain cannot be obtained and the S / N becomes lower, the beam forming accuracy is lowered, and a large amount of calculation is required because many integration processes are required at the time of detection.

  The present invention has been made to solve the above-described problems. The transmission is performed with a different modulation for each transmission element antenna, and the transmission side is demodulated and separated for each transmission element antenna, thereby virtually transmitting on the reception side. It is also intended to perform high-precision beam forming with a small amount of calculation even at low S / N by performing reception beam forming and repeatedly performing virtual reception beam forming and transmission beam forming processing.

The transmission / reception device according to the present invention provides:
A plurality of transmitters that radiate encoded transmission signals having different waveforms for each antenna from a plurality of antennas;
Waveform generating means for generating and transmitting encoded transmission signals having different waveforms for each antenna to a plurality of transmitters;
A plurality of receivers that receive and input received signals reflected by the target from each of the plurality of antennas;
A plurality of separation means provided corresponding to each receiver, and separating a received signal into different waveforms at the time of transmission;
Propagation matrix generation means for generating a propagation matrix based on signals separated by a plurality of separation means;
A received load calculating means for calculating a received load vector from the received steering vector via the propagation matrix of the propagation matrix generating means;
A transmission load calculation means for calculating a transmission load vector from a transmission steering vector via a propagation matrix of the propagation matrix generation means from the reception load calculation means;
Transmit beam combining means for combining a transmit beam from a transmit weight vector and a propagation matrix;
Receiving beam combining means for performing virtual reception beam combining processing from the combined vector of the transmission beam obtained by the transmission beam combining means and the received weight vector from the reception load calculating means,
The transmission beam combining means sends a new reception steering vector by transmission beam combining to the reception load calculation means, the reception load calculation means calculates a new reception load vector from the new reception steering vector, and the transmission load calculation means A new transmission weight vector is calculated from the new reception weight vector, and the transmission beam combining means performs a process of combining a new transmission beam from the new transmission weight vector. The gain of the transmission weight vector converges to an ideal value. It is repeatedly executed until a predetermined value is reached.

  According to the transmission / reception apparatus according to the present invention, the transmission signal radiated from the antenna is encoded into different waveforms, the reception signal received from the antenna is separated into different waveforms, processed, and the virtual transmission is performed by the separated reception signal. Therefore, it is possible to obtain accurate transmission and reception beam forming at low calculation cost even at low S / N. Also, because transmit beam forming is performed as signal processing on the receiving side, even when the amplitude of the optimal transmit beam forming load is different as in a multipath environment, it is not necessary to perform amplitude control by conventional H / W and accurate Beam forming can be performed. Furthermore, since iterative processing is performed as signal processing on the receiving side, it is not necessary to transmit transmission waves repeatedly, and accurate beam forming can be performed.

It is a block diagram which shows Embodiment 1 of the transmission / reception apparatus of this invention. FIG. 3 is a process flowchart of the first embodiment. FIG. 3 is a characteristic diagram of gain fluctuation when a load vector is calculated according to the iterative process of FIG. 2 when eight antennas are used. It is a processing flow figure showing other embodiments using multi-beam formation processing. It is a block diagram which shows Embodiment 3 of the transmission / reception apparatus of this invention. FIG. 5 is a layout diagram of transmission / reception antennas for matching transmission / reception steering vectors in a radar in which radio waves propagate horizontally with respect to the ground surface. It is condition explanatory drawing of the antenna arrangement | positioning with which the synthetic | combination steering vector of a direct wave and a multipath wave does not change by transmission / reception in a multipath environment. FIG. 10 is a processing flowchart of the fourth embodiment.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing Embodiment 1 of the transmitting / receiving apparatus of the present invention. In the figure, 1 is a waveform generating means for generating a different signal waveform for each transmission antenna, 4 is a plurality of antennas, 2 is a plurality of transmitters provided corresponding to the plurality of antennas 4, and 5 is a plurality of antennas. 4 is a plurality of receivers provided corresponding to 4 respectively, 3 is a plurality of switching means for switching and connecting each antenna 4 to each transmitter 2 or each receiver 5, and 6 is each receiver. A plurality of separation means for separating the received signal from 5 for each transmission waveform, and 7 is a signal processing means for synthesizing the signals separated for each transmission waveform from the separation means 6. 8 is a propagation matrix generating means for rearranging the separated signal vectors obtained as a result of the separating means 6 to generate a propagation matrix, and 9 is a received weight vector for virtual load synthesis by an inner product operation of vectors constituting the propagation matrix. Received load calculation means to be obtained 10 is a transmission load calculation means for obtaining a virtual transmission load vector from a reception load vector by the reception load calculation means 9, and 11 is a transmission beam for performing a virtual transmission beam combining process using the transmission load vector. A combining unit 12 is a receiving beam combining unit that performs a virtual reception beam combining process from a combined vector of a virtual combined transmission beam obtained by the transmission beam combining unit 11 and a reception load vector from the reception load calculation unit 9. .

In addition, a new virtual received weight vector is repeatedly calculated in the received load calculating means 9 from the result of the combined vector obtained by the transmitted beam combining means 11.
The signal processing unit 7 includes a propagation matrix generation unit 8, a reception load calculation unit 9, a transmission load calculation unit 10, a transmission beam synthesis unit 11, and a reception beam synthesis unit 12.
Further, the waveform generating means 1 generates different signal waveforms by changing either the sign or time or frequency, and the separating means 6 is configured to separate the signals based on different waveform information generated by the waveform generating means. The

  FIG. 2 shows a processing flow of the present embodiment, and the operation of the first embodiment will be described with reference to FIGS. 1 and 2.

Generated by the waveform generating means 1, a transmission signal waveform to be transmitted from the j th antenna 4 and s _j (t), a signal vector which is composed of s _j (t) as shown in the following equation (1) and S To do. Here, it is assumed that the signal waveforms s _j (t) are independent of each other.

This transmission signal waveform s _j (t) is transmitted from the antenna 2 via the switching means 3 from the transmitter 2. The switching means 3 operates so that the antenna 4 and the transmitter 2 are connected at the time of transmission and the antenna 4 and the receiver 5 are connected at the time of reception, and corresponds to, for example, a circulator used in a radar. For example, in a radar as a transmission / reception device, a transmission signal comes into contact with a target and is reflected, and the reflected wave is received by the antenna 4 again. FIG. 1 shows an example of shared transmission / reception antennas using the switching means 3, and the case where the transmission / reception antennas are different will be described in another embodiment.
The phase and amplitude of the signal waveform transmitted from the j-th antenna fluctuate due to the influence of distance and multipath before reaching the target. Let this fluctuation amount be _atj . Similarly, the amount of variation in the phase and amplitude of the received signal that reaches the i-th antenna after being in contact with the target and reflected is assumed to be _ari . The vectors having these fluctuation amounts a _tj and a _ri as elements are called a transmission steering vector and a reception steering vector, and are defined as a _t and a _r respectively as shown in the following equations (2) and (3).

From the symmetry of the transmission and reception, if reception of the antenna are the same, the received steering vector a _r a transmit steering vector a _t can be considered to match.
Next, a propagation matrix H whose element is a phase amplitude change amount h _y transmitted from the j-th antenna and reflected by contact with the target and reflected by the i-th antenna is expressed by the following equation (4). Defined in At this time, the propagation matrix can be expressed as Equation (5) using the transmission steering vector and the reception steering vectors a _t and a _r .

A signal received by the i-th antenna is defined as y _i (t), and a signal vector Y composed of the received signal is defined as the following equation (6). At this time, the signal vector Y can be expressed as in Expression (7) using the transmission / reception steering vector and the propagation matrix. Here, the clutter, which is a reflected wave other than the target wave, is ignored because it can be sufficiently suppressed by MTI (Moving Target Indicator) which is the signal processing of the radar. The receiver noise is omitted for the sake of simplicity.

Next, the separation means 6 receives the reception signal from the receiver 5 and separates the reception signal for each signal generated by the waveform generation means 1. In order to obtain the component r _ij of the transmission signal of the j-th antenna from the i-th received signal, for example, correlation processing as shown in Equation (8) is performed, and the maximum value for the time difference τ is set as the correlation value. And Here, E [] represents a time average. The superscript * indicates the complex conjugate. When the i-th received signal y _i (t) is expressed as in Expression (9), the signal waveforms s _j (t) are orthogonal to each other. Assuming that the power is all 1 for simplicity of explanation, the correlation becomes maximum when the timing of the transmission waveform component in the received signal matches the timing of the transmission waveform of the transmission signal from the antenna 4. Considering this, the correlation value matches the element of the propagation matrix as shown in equation (10).

  As described above, since all the elements of the propagation matrix are obtained by the separating means 6, it can be seen that the propagation matrix can be obtained by inputting the output of the separating means 6 in step S1 of FIG.

Next, a method of performing reception and transmission beam forming from the propagation matrix will be described with reference to FIG. However, the transmission beam formation in the present invention is a virtual one that is performed as signal processing on the reception side, and does not actually form a transmission beam like conventional radar.
For example, in the conventional configuration, the same signal waveform s (t) is transmitted from all antennas by forming a beam with the transmission beam forming load vector W _t defined by Equation (11), and the received beam shown in Equation (12) the output signal s _o when the formation load vector W _r performs receive beamforming of the received signal (t) is given by equation (13).

Accordingly, when the norm of the transmission beam forming weight vector W _t and the receiving beam forming weight vector W _r is constant, for example, 1, the reception S / N is maximized by maximizing the absolute value of W _r ^T HW _t . can do. The reason for making the norm constant is that the noise power is also amplified by the norm of the load vector, so that the S / N is not affected. The load vector that maximizes the S / N is called an optimum load vector. As is clear from the equation (13), the optimal weight vectors for transmission and reception are complex conjugate vectors for transmission and reception, respectively, and are given by the following equations (14) and (15). k _t and k _r are coefficients for normalizing the norm of the load vector to 1, and do not affect the output S / N as described above.

In the present invention, N _t N _r signals Y _r corresponding to the elements of the propagation matrix are obtained by transmitting the transmissions with different modulations and separating them on the receiving side. If the demodulated signal is s (t), _Yr is given by the following equation (16). To which was load synthesized to obtain an output signal s _o (t), may be multiplied from the front and back of a suitable weight vector W _t and W _r the propagation matrix as shown in equation (17). It can be seen that this is an equation equivalent to the conventional beam forming equation (13). Therefore, in the following description, the virtual transmission and reception beam forming vectors W _t and W _r will be referred to as a transmission weight vector and a reception weight vector, respectively.

From the above, the optimum load vector that maximizes the S / N of the output signal can be selected to maximize the absolute value of W _r ^T HW _t under the constant norm, and the equation ( 14) and (15).

In the received load calculation processing step S2 in FIG. 2, the received load vector is calculated by the received load calculating means 9 using the propagation matrix H calculated in step S1. First, the propagation matrix H can express the equation (5) as the equation (18). It can be seen that all of the elements has become multiplied by the coefficient to the transmit steering vector a _t see this equation (18). Therefore, as shown in Equation (19), a vector corresponding to one receiving antenna is used as a reference vector, and the complex conjugate vector is multiplied by the propagation matrix to obtain a vector that is a scalar multiple of the reception steering vector a _r as shown in the equation. Can be obtained.

The reception optimum load vector W _r is obtained as a complex conjugate vector of the reception steering vector a _r as shown in the equation (15). In order to avoid divergence due to an iterative process described later, the norm is always normalized to 1 in the subsequent load vector calculation.

By the way, since the propagation matrix actually includes noise, there is a problem that accuracy is low at low S / N. Therefore, in the present invention, the accuracy of the load vector is gradually improved by iterative processing.
Although the case where the propagation vector is multiplied by the reference vector is shown here, the vector to be multiplied as the first processing is arbitrary, and for example, a vector in which all the elements are 1 may be used.
The received load vector may be calculated from the eigenvector corresponding to the maximum eigenvalue of H ^H H, but the method described here is simpler. Here, the superscript H indicates complex conjugate transpose.

The transmission optimal load vector in the transmission load calculation processing step S3 by the transmission load calculation means 10 in FIG. 2 matches the reception optimal load vector because the transmission and reception steering vectors are the same when the transmission and reception antennas are the same. . Therefore, the reception optimum load vector obtained in the reception load calculation processing step S2 by the reception load calculation means 9 is repeatedly used as the transmission optimum load vector.
Sending synthesis process step S4 in the transmission beam combining means 11, by multiplying the optimal weight vector W _t of the transmission as shown in the following equation (20) in the propagation matrix H, beam combining processing equivalent of the transmission is performed. As a result, a new reception steering vector is obtained. In the reception load calculation processing step S2 in the reception load calculation means 9, this complex conjugate vector is repeatedly used as the reception optimal load vector. Are repeatedly performed as a series of processes called a virtual beam synthesis process.
The received load vector is calculated in the same manner in the received load calculation processing step S2 in the received load calculation means 9 and in the transmission synthesis processing step S4 in the transmission beam combining means 11, but these are independent processes. The accuracy of the load vector can be gradually improved.
In the reception synthesis processing step S5, the reception beam synthesis means 12 further calculates the inner product of the reception steering vector obtained by the equation (20) and the reception weight vector obtained in the reception load calculation processing step S2 in the reception weight calculation means 9. To obtain an output signal.

FIG. 3 shows a change in gain when a load vector is calculated according to the iterative process of FIG. 2 when eight antennas are used. The horizontal axis represents the number of iterations, and the vertical axis represents the gain based on the received load vector. In the ideal case where the load vector matches the steering vector, a gain of 9 dB is obtained. From this, it can be seen that the load vector is inaccurate and the gain is low because the S / N is low at the number of iterations of 1, but converges to an ideal gain when the number of iterations is 2 or more. .
Thus, it can be seen that an accurate load vector can be obtained by iterative processing even in a low SNR environment.

  As described above, in the transmission / reception apparatus of the present invention, the transmission signal is encoded, the reception signal is separated and processed, and virtual transmission and reception beam forming are repeatedly performed. Even in N, accurate transmission and reception beam forming can be obtained at a low calculation cost. Also, because transmit beam forming is performed as signal processing on the receiving side, even when the amplitude of the optimal transmit beam forming load is different as in a multipath environment, it is not necessary to perform amplitude control by conventional H / W and accurate Beam forming can be performed. In addition, since iterative processing is performed as signal processing on the receiving side, it is not necessary to transmit transmission waves repeatedly, and accurate beam forming can be performed.

  In this example, the method of obtaining the received weight vector first by paying attention to the row vector of the propagation matrix and performing transmission composition processing using it as the transmitted weight vector to obtain a new received weight vector has been explained. Focusing on the column vector of the matrix, the same effect can be obtained by obtaining the transmission weight vector first, performing reception synthesis processing using this as the reception weight vector, and obtaining a new transmission weight vector.

Embodiment 2. FIG.
FIG. 4 is a process flow diagram showing another embodiment using the multi-beam forming process. The overall configuration is the same as in FIG. 1, and only the signal processing portion is different.
In FIG. 4, S6 is a processing step of generating a separate vector a _v as shown in equation (21) side by side output of the separating means 6 in the propagation matrix generation unit 6 as an element of the vector. Equation (21) is obtained by arranging the reception steering vectors by the number of transmission elements, and represents a virtual array steering vector in the MIMO radar. S7 is a processing step in which the reception load calculation means 9 performs multi-beam forming processing by inner product processing with a plurality of fixed beam forming load vectors W _v with respect to the separation vector a _v . This processing can be performed by Fourier transform when the virtual array in the MIMO radar is an equally spaced array.

By selecting a beam forming load vector having the largest received power by the multi-beam forming process in S7, it is possible to obtain a fixed beam forming load vector W _v close to the optimum beam forming load vector. Complex conjugate vector of the fixed beamforming weight vector W _v is virtual because steering vector a _v correspond, fixed beamforming weight vector W _v elements of the reception of the load vector W _r and the transmission of the load vector W _t w _{Since t1} ... _wtNt is used to _express the following equation (22), it is possible to obtain the first reception and transmission weight vectors W _r and W _t in the iteration.

In the subsequent processing, the reception optimum load vector W _r is obtained from the product of the transmission load vector W _t and the propagation matrix H using the equation (20) as in the first embodiment, and this is obtained as the transmission load vector W _t. the process is repeated to obtain the optimal weight vector W _r of reception by multiplying the propagation matrix H repeatedly used as.

In the present embodiment, as described above, it is possible to obtain accurate transmission and reception beam forming at low calculation cost even at low S / N by repeatedly performing virtual transmission beam forming and reception beam forming. Can do.
Furthermore, in addition to the effects of the first embodiment, there is an effect that an optimum load vector can be obtained with a small number of iterations by performing the multi-beam forming process.

  In the present embodiment, the same effect can be obtained even if the order of obtaining the optimum load for reception and transmission is reversed.

Embodiment 3 FIG.
FIG. 5 is a configuration diagram illustrating the third embodiment. The difference from the first embodiment shown in FIG. 1 is that the transmission and reception have different antennas, and the other configuration is the same as that of FIG.

  In the first embodiment, since the transmission antenna and the reception antenna are the same, the transmission and reception steering vectors coincide with each other. Therefore, the reception optimum load vector can be used repeatedly as the transmission optimum load vector. However, since the transmission antenna and the reception antenna are different in the third embodiment, there is a problem that the steering vectors generally do not match. Therefore, the present embodiment is characterized in that the antennas are arranged so that the transmission and reception steering vectors match even when the transmission antenna and the reception antenna are different.

  For example, in the case where radio waves are assumed to propagate horizontally with respect to the ground surface, such as when observing a distant place with a radar, the transmitting antenna and the receiving antenna are arranged in the vertical direction with the same arrangement as shown in FIG. If they are shifted to each other, the transmission and reception steering vectors can be matched. As a result, the received optimum load vector can be repeatedly used as the optimum load vector for transmission as in the first embodiment, and the same effect as in the first embodiment can be obtained.

Next, FIG. 7 shows antenna arrangement conditions for preventing the combined steering vector of direct waves and multipath waves from changing between transmission and reception when a multipath environment from the ground surface or the like is assumed.
First, consider a case where antenna A and antenna A ′ having the same array arrangement are arranged with a displacement vector δ. Assume that direct waves and multipath waves arrive at these antennas, b ₁ is the direct wave vector from the wave source to antenna A, and b is the multipath wave vector from the mirror image of the wave source to the antenna A in FIG. ₂ Also, let b ₁ 'be the direct wave vector from the wave source to the antenna A', and b ₂ 'be the multipath wave vector from the mirror image of the wave source to the antenna A' on the reflecting surface in FIG. Since the antenna A and the antenna A ′ have the same array arrangement, if the wave source is sufficiently far away, the steering vectors for the same wave are considered to be equal. Therefore, the direct wave steering vector is a _d , and the multipath wave steering vector is a _m . At this time, if the combined steering vector of the direct wave and the multipath wave of the antenna A is a _s , and the combined steering vector of the direct wave and the multipath wave of the antenna A ′ is a _s ′, the combined steering vector a _{s of the} antenna A and the antenna The combined steering vector a _s ′ of A ′ is given by the following equations (23) and (24) with reference to the wave source.

In order to reduce the fluctuation of the steering vector when the antenna is displaced, the difference between a _s and a _s ′ should be small. However, since the coefficient applied to the vector only changes the entire phase, it does not affect the beam formation and can be ignored.

  When this difference is D, the following equation (25) is obtained. Here, D can be read as a difference in distance between the direct wave antenna A and the antenna A 'and a difference in distance between the antenna A and the antenna A' in the multipath wave.

From the result of Equation (28), if the antenna is shifted in the direction orthogonal to the difference vector between the assumed unit direction vector of the direct wave and the unit direction vector of the multipath wave, the difference between the steering vectors of both can be reduced. .
In the present embodiment, using the above properties, the transmitting and receiving antennas are shifted in the direction orthogonal to the difference vector of the direction unit vector of the assumed direct wave and multipath wave. . By arranging in this way, it is possible to repeatedly obtain the optimal load vector for reception as the optimal load vector for transmission as in the first embodiment, and to perform accurate transmission even in low S / N in a multipath environment. There is an effect that beam forming for reception can be obtained at low calculation cost.

  In the present embodiment, the same effect can be obtained even if the order of obtaining the optimum load for reception and transmission is reversed.

Embodiment 4 FIG.
FIG. 8 shows a processing flow of the fourth embodiment. The fourth embodiment is an effective iterative processing method even when the transmission and reception antenna steering vectors are different, and the overall configuration is the same as in FIG. In the present embodiment, the number of transmitting element antennas may be different from the number of receiving element antennas.

The operation will be described below based on the configuration diagram of FIG. First, similarly to the first embodiment, the propagation matrix H shown by the equation (4) is obtained from the output of the separating means 6 by the propagation matrix generating means 8. In step S2 of FIG. 8, the reception weight calculation means 9 uses the vector corresponding to one reception antenna as a reference vector as shown by the equation (19), and multiplies the complex conjugate vector to the propagation matrix, thereby receiving the steering vector. Get. A reception optimum load vector is obtained from the complex conjugate vector of the reception steering vector. Note that the transmission load vector may be determined as an appropriate initial value instead of the reference vector, and this may be multiplied by the propagation matrix to obtain the optimal load vector for the first reception. Also the load vector W _r of reception obtained at the step S2 the reception load calculation means 9 multiplied by the propagation matrix as shown in Equation (29) in step S5, performs a virtual receive synthetic, this result is transmitted load The calculation means 10 calculates the optimum load vector for transmission in step S3. Using the optimal weight vector W _t of the transmission obtained in step S3, performing a virtual send synthesized as shown in equation (30) in the step S4 by the transmission beam combining means 11. A new reception steering vector is obtained by this virtual transmission synthesis process. The received load calculation means 9 repeats in step S2 from this new received steering vector to obtain a new received optimum load vector. Thereafter, by calculating the optimum load vector repeatedly based on the equations (29) and (30), an accurate load vector can be obtained gradually even at low S / N.
In step S4, the transmission beam combining unit 11 ends the iterative process when the gain of the transmission weight vector reaches a predetermined value close to the ideal value, and outputs the received steering vector to the reception beam combining unit 12.
In step S8, an output value is obtained from the inner product of the reception steering vector obtained in step S4 and the reception optimum load vector obtained in step S2 by the reception beam combining means 12.

  As described above, in this embodiment, in addition to the effects of the first embodiment, an accurate beam forming load vector is obtained by iterative processing even when the transmission antenna and the reception antenna are different and the transmission and reception steering vectors are different. There is an effect that can.

In the present embodiment, the same effect can be obtained even if the order of obtaining the optimum load for reception and transmission is reversed.
Further, the waveform generating unit 1 may generate a waveform at a predetermined interval, and the separating unit 6 may be configured to separate the signal based on the waveform information generated by the waveform generating unit.

  The present invention may be used as a radar transmission / reception device that detects a target by radiating radio waves from a plurality of antennas, receiving radio waves reflected by a target, processing a received signal, and detecting the target.

DESCRIPTION OF SYMBOLS 1; Waveform generation means, 2; Transmitter, 3; Switching means, 4; Antenna, 5; Receiver, 6; Separation means, 7: Signal processing means, 8; Propagation matrix generation means, 9; 10; transmission load calculation means; 11; transmission beam combining means; 12; reception beam combining means.

Claims (7)

A plurality of transmitters that radiate encoded transmission signals having different waveforms for each antenna from a plurality of antennas;
Waveform generating means for generating and transmitting encoded transmission signals having different waveforms for each antenna to a plurality of transmitters;
A plurality of receivers that receive and input received signals reflected by the target from each of the plurality of antennas;
A plurality of separation means provided corresponding to each receiver, and separating a received signal into different waveforms at the time of transmission;
Propagation matrix generation means for generating a propagation matrix based on signals separated by a plurality of separation means;
A received load calculating means for calculating a received load vector from the received steering vector via the propagation matrix of the propagation matrix generating means;
A transmission load calculation means for calculating a transmission load vector from a transmission steering vector via a propagation matrix of the propagation matrix generation means from the reception load calculation means;
Transmit beam combining means for combining a transmit beam from a transmit weight vector and a propagation matrix;
Receiving beam combining means for performing virtual reception beam combining processing from the combined vector of the transmission beam obtained by the transmission beam combining means and the received weight vector from the reception load calculating means,
The transmission beam combining means sends a new reception steering vector by transmission beam combining to the reception load calculation means, the reception load calculation means calculates a new reception load vector from the new reception steering vector, and the transmission load calculation means A new transmission weight vector is calculated from the new reception weight vector, and the transmission beam combining means performs a process of combining a new transmission beam from the new transmission weight vector. The gain of the transmission weight vector converges to an ideal value. A transmission / reception device that repeatedly executes until a predetermined value is reached. The transmission antenna and the reception antenna are the same antenna, and includes switching means for performing switching connection between the antenna and the transmitter or receiver,
The transmission / reception apparatus according to claim 1, wherein the transmission load calculation means uses the reception load vector from the reception load calculation means as it is as the transmission load vector to be calculated.   The number of transmit antennas and receive antennas is the same, and the direction unit vectors of the direct wave and multipath wave from the target are such that the steering vectors of the transmit antenna and the receive antenna match the expected direction of arrival from the target. The transmission / reception apparatus according to claim 1, wherein the transmission and reception antennas are shifted in a direction orthogonal to the difference vector. A plurality of transmitters that radiate encoded transmission signals having different waveforms for each antenna from a plurality of antennas;
Waveform generating means for generating and transmitting encoded transmission signals having different waveforms for each antenna to a plurality of transmitters;
A plurality of receivers that receive and input received signals reflected by the target from each of the plurality of antennas;
A plurality of separation means provided corresponding to each receiver, and separating a received signal into different waveforms at the time of transmission;
Propagation matrix generation means for generating a propagation matrix based on signals separated by a plurality of separation means;
A reception weight calculation means for obtaining a reception optimum load vector from the reception steering vector via the propagation matrix of the propagation matrix generation means, further multiplying the reception optimum load vector by the propagation matrix, and performing virtual reception synthesis;
A transmission load calculation means for calculating an optimal transmission load vector from a virtual reception synthesis result;
Transmit beam combining means for performing virtual transmission combining using the optimal load vector for transmission and obtaining a new reception steering vector by this virtual transmission combining processing;
The reception load calculation means obtains a new reception optimum load vector from the new reception steering vector. Thereafter, the transmission load calculation means, the transmission beam synthesis means, and the reception load calculation means determine the transmission load vector in the transmission beam synthesis means. Iterates until the gain reaches a certain value close to the ideal value, iteratively calculates the optimal load vector, and when the iteration process is complete, outputs the received steering vector,
A transmission / reception apparatus comprising: a reception beam combining unit that performs a virtual reception beam combining process from a transmission beam combined vector obtained by a transmission beam combining unit and a reception load vector from a reception load calculation unit, and outputs the result.   The waveform generation unit generates a different signal waveform by different sign or time or frequency, and the separation unit separates the signal based on different waveform information generated by the waveform generation unit. The transmission / reception apparatus according to any one of 1 to 4. The propagation matrix generation means is configured to generate a propagation matrix, arrange the output of the separation means as a vector element, and generate a separation vector.
The reception load calculation means forms a multi-beam by using a plurality of beam forming load vectors fixed to the separation vector of the propagation matrix generation means as the initial reception load vector, and the beam forming load vector having the largest reception power is generated from the multi-beam. The transmission / reception apparatus according to claim 1, wherein the transmission / reception apparatus is configured to select, obtain a fixed beamforming load vector, and use the obtained reception load vector.   The transmission / reception according to claim 1, wherein the waveform generation unit generates a waveform at a predetermined interval, and the separation unit separates the signal based on waveform information generated by the waveform generation unit. apparatus.

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