JP6382635B2 - Radar system and radar signal processing method thereof - Google Patents

Description

  The present embodiment relates to a radar system that detects a target position using a plurality of radar devices that are spaced apart from each other, and a radar signal processing method thereof.

  Recently, in the radar system, a multi-static method has been developed in which one or more transmission / reception radar devices or reception radar devices are arranged apart from the transmission / reception radar device, and the target position is detected based on the observation results of each radar device. Has been. In this type of radar system, if time synchronization between remote radar devices is insufficient, if there is a shift in the center frequency, and if distance accuracy or Doppler accuracy is insufficient, errors in observation position and Doppler velocity will occur. There was a problem that would increase.

JP 2009-121902 A

Bistatic radar Doppler frequency, M. Skolnik, Radar Handbook 3rd, McGraw hill, pp23.14-23.15 (2008) Phase monopulse (phase comparison monopulse) method, IEICE, revised radar technology, pp.262-264 (1996) Amplitude monopulse (amplitude comparison monopulse) system, IEICE, revised radar technology, pp.260-262 (1996) Tailor distribution, Yoshida, 'Revised radar technology', IEICE, pp.134-135 (1996) FMCW method (up-chirp and down-chirp), Yoshida, "Revised radar technology", IEICE, pp.274-275 (1996) FMICW, FRED E. Nathanson, 'RADAR DESIGN PRINCIPLES second edition', Scitech, p452-454 (1999)

  As described above, the conventional multistatic radar system has a problem that the distance accuracy and the speed accuracy are insufficient due to the influence of the time synchronization shift and the center frequency shift between the radar devices.

  The present embodiment has been made in view of the above-described problems. A radar system and a radar signal processing method for outputting a highly accurate position and speed by reducing the influence of time synchronization deviation and center frequency deviation between radar apparatuses and the like. The purpose is to provide.

In order to solve the above-described problem, the present embodiment provides at least one transmission / reception radar apparatus that transmits / receives at least one continuous wave of an up sweep or a down sweep having a frequency sweep gradient as a radar wave, and the transmission / reception radar apparatus. Nr units that are arranged at positions different from each other, obtain information on at least the position, transmission beam direction, transmission frequency, and transmission waveform of the transmission / reception radar apparatus and receive a reflected wave of the radar wave transmitted from the transmission / reception radar apparatus (Nr ≧ 2 ) a reception radar device, and an integrated processing device that integrates the output of the transmission / reception radar device and the output of the reception radar device, wherein the transmission / reception radar device and the reception radar device are each of the radar Receives reflected waves and measures the target position by MRAV (Measurement Range After measurement Velocity) processing The integrated processing device measures the distance difference from the transmission position of the transmission / reception radar device to the reception position of each of the Nr reception radar devices via a target by Nr distance differences R1n. The intersection is calculated from (n = 1 to Nr), and the three-dimensional position (x, y, z) of the target is calculated.

1 is a block diagram showing a configuration of a radar system according to a first embodiment. The flowchart which shows the flow of the signal processing of 1st Embodiment. The flowchart which shows the MRAV signal processing of 1st Embodiment. The timing diagram for demonstrating the processing cycle of 1st Embodiment. The frequency distribution figure which shows (SIGMA) and (DELTA) beam distribution on the frequency axis by the phase monopulse of 1st Embodiment. The frequency distribution figure which shows a mode that the target frequency is extracted from the (SIGMA) and (DELTA) beam on the frequency axis by the phase monopulse of 1st Embodiment. The frequency distribution figure and characteristic figure for demonstrating the error voltage calculation process by the phase monopulse of 1st Embodiment. The conceptual diagram for demonstrating the sweep process in the unit cycle of 1st Embodiment. The perspective view which shows a mode that a three-dimensional speed is calculated with high precision in the signal processing of 1st Embodiment. The block diagram which shows the structure of the radar system which concerns on 2nd Embodiment. The flowchart which shows the flow of the signal processing of 2nd Embodiment. The conceptual diagram for demonstrating the bistatic transmission / reception of 2nd Embodiment. The conceptual diagram for demonstrating bistatic transmission / reception at the time of extending to three dimensions in 2nd Embodiment. The block diagram which shows the structure of the radar system which concerns on 3rd Embodiment. The flowchart which shows the flow of the signal processing of 3rd Embodiment. The figure for demonstrating the process of the time synchronization of 3rd Embodiment. The block diagram which shows the structure of the radar system which concerns on 4th Embodiment. The flowchart which shows the flow of the signal processing of 4th Embodiment. The block diagram which shows the structure of the radar system which concerns on 5th Embodiment. The flowchart which shows the flow of the signal processing of 5th Embodiment. The figure which shows the mode of the modulation / demodulation of 5th Embodiment. The block diagram which shows the structure of the radar system which concerns on 6th Embodiment. The flowchart which shows the flow of the signal processing of 6th Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. In the description of each embodiment, the same portions are denoted by the same reference numerals, and redundant description is omitted.

(First Embodiment) (Position output by MRAV)
The radar system according to the first embodiment will be described with reference to FIGS. 1 to 9. FIG. 1 is a block diagram showing a system configuration of the radar system, FIG. 2 is a flowchart showing a specific processing flow thereof, FIG. 3 is a flowchart showing MRAV signal processing, and FIG. 4 is a timing diagram for explaining a processing cycle. FIGS. 5A and 5B are frequency distribution diagrams showing the Σ and Δ beam distributions on the frequency axis by the phase monopulse, respectively, and FIG. 6 extracts the target frequency from the Σ and Δ beams on the frequency axis by the phase monopulse. FIGS. 7A and 7B are frequency distribution diagrams and characteristic diagrams for explaining error voltage calculation processing using phase monopulses, and FIGS. 8A and 8B are unit cycles. FIG. 9 is a perspective view showing how to calculate a three-dimensional speed with high accuracy.

  The radar system shown in FIG. 1 includes one transmission / reception radar apparatus A and a plurality (two in this case) of reception radar apparatuses arranged at positions where the reflected wave of the radar signal transmitted from the transmission / reception radar apparatus A can be received. B and C are provided.

  In the transmission / reception radar apparatus A, the antenna A1 is a phased array antenna in which a plurality of antenna elements are arranged to form a large aperture array. In the transmitter / receiver A2, the transmitter / receiver A21 generates an FMCW (Frequency Modulated Continuous Wave, see Non-Patent Document 5) sweep signal or a pulse-modulated FMICW (Frequency Modulated Interrupted Continuous Wave, see Non-Patent Document 6). The beam control unit A22 directs the beam transmitted from the antenna A1 in the target direction. The transmission / reception unit A21 receives the signal reflected from the target, demodulates it with a local signal using the same FMCW sweep signal as the transmission waveform, and converts the frequency to baseband (FIG. 2: sweep transmission / reception in step SA11). The sweep reception signal obtained in this way is sent to the signal processor A3.

  The signal processor A3 distributes the sweep reception signal to the Σ beam system and the Δ beam system. The sweep reception signal input to the Σ beam system is converted into a digital signal by an AD (Analog-Digital) converter A31 (FIG. 2: step SA12), and multiplied by a Σ weight for FFT in the weight multiplier A32 (see FIG. 2). 2: Step SA13), converted into a frequency domain signal by the FFT processing unit A33 (FIG. 2: Step SA14), and detection of cells (time samples) exceeding a predetermined threshold is executed by the CFAR detection unit A34 (FIG. 2). : Step SA15). Subsequently, distance measurement / speed measurement calculation is performed by the MRAV processing unit A35 (FIG. 2: step SA16), and the calculation result is sent to the angle measurement unit A36.

  On the other hand, the PRF reception signal input to the Δ beam system is converted into a digital signal by the AD conversion unit A37 (FIG. 2: step SA12), and the weighting unit A38 multiplies the Δweight for FFT (FIG. 2: step). SA13), the signal is converted into a frequency domain signal by the FFT processing unit A39 (FIG. 2: step SA14) and sent to the angle measuring unit A36. The angle measurement unit A36 performs angle measurement based on the distance measurement / speed measurement calculation result obtained by the MRAV processing of the Σ beam system and the Δ detection signal obtained by the Δ beam system (FIG. 2: step SA17). .

  The reception radar devices B and C have the same configuration except for the transmission function of the transmission / reception radar device A. That is, in the receiving radar apparatuses B and C, the antennas B1 and C1 are receiving phased array antennas in which a plurality of antenna elements are arranged to form a large aperture array, and are specified to be repeatedly transmitted from the transmitting / receiving radar apparatus A. A reflected wave of a frequency radar signal is received. In the receivers B2 and C2, in the receiving units B21 and C21, the signals received by the antennas B1 and C1 are subjected to phase control in accordance with instructions from the beam control units B22 and C22 to synthesize a received beam in an arbitrary direction. The PRF reception signal is formed, and the frequency is converted to the baseband (FIG. 2: sweep reception at steps SB11 and SC11). The sweep reception signals obtained in this way are sent to the signal processors B3 and C3 and distributed to the Σ beam system and the Δ beam system in the same manner as the transmission / reception radar apparatus A, and the distance measurement and angle measurement at the CFAR detection target are performed. Calculation is performed (FIG. 2: steps SB12 to SB17, SC12 to SC17). The distance measurement / angle measurement results of the detection targets obtained by the radar devices A, B, and C are sent to the integrated processing device D, and the target distance, speed, and angle determined to be identical to each other are output as target information. (FIG. 2: Step SD11).

  In the above configuration, a processing operation for reducing the influence of a time synchronization shift, a center frequency shift, etc. between the radar apparatuses A, B, and C will be described with reference to FIGS. 3 is a flowchart showing MRAV signal processing, FIG. 4 is a timing diagram for explaining a processing cycle, FIG. 5 is a frequency distribution diagram showing Σ and Δ beam distributions on the frequency axis by phase monopulse, and FIG. 6 is phase monopulse. FIG. 7 is a frequency distribution diagram and characteristic diagram for explaining error voltage calculation processing by phase monopulse, and FIG. 8 is a unit cycle. FIG. 9 is a perspective view showing how a three-dimensional speed is calculated with high accuracy in signal processing.

  First, the distance measurement / speed measurement procedure by MRAV will be described with reference to FIG. Here, as shown in FIG. 4, the transmission signal waveform is described in the case of two down sweeps at the time interval T12. However, as a down-up sweep continuous waveform, only one of the down sweeps or only the up sweeps is shown. It may be when processing. For simplicity, the case of two sweeps will be described, but it goes without saying that the same applies to N (N> = 2) times.

In FIG. 3, when signals 1 and 2 that continuously sweep the frequency are transmitted and received (step S10), the sample sequence of sweeps 1 and 2 is subjected to FFT processing to perform monopulse calculation (step S11), and threshold detection (step S12). The beat frequency fp having the peak signal is extracted and stored by (step S13). When the processing of the sweep signals 1 and 2 is completed in steps S14 and S15, the relative distances R1 and R2 are calculated from the following equations using the beat frequencies fp of the sweep 1 and the sweep 2, and the velocity v is calculated (step S16). .

Next, the target distance R is calculated by the following simultaneous equations using the beat frequency fp and the velocity v obtained by the equation (2) (step S17).

  The above method is called a MRAV (Measurement Range after Measurement Velocity) method (refer to Patent Document 1) because the distance is calculated after the velocity is calculated based on the beat frequency.

  After calculating the speed v and the distance R by the above processing, it is stored as target information (step S18). The above steps S16 to S18 are performed for all targets (steps S19 and S20), and the process proceeds to the next cycle.

  Here, there is a method for improving the observation accuracy of the beat frequency. In particular, when the beat frequency is within the same bank between sweeps, such as when the target speed is low, it is necessary to calculate the beat frequency accurately within the same bank. As a countermeasure against this, as shown in FIGS. 5A, 5B, and 6, a method of observing the frequency in the bank with high accuracy using a phase monopulse (see Non-Patent Document 2) used on the angle axis on the frequency axis. It is. The procedure is shown below.

(1) Frequency axis monopulse Using the extracted target frequency Σ (fp) and Δ (fp), an error voltage ε of the following equation is calculated (see FIGS. 7A and 7B).

(2) Beat frequency extraction The error voltage reference value ε0 calculated using the previously stored frequency characteristics of Σ and Δ is tabulated (corresponding to ε0 and frequency f), and using the reference table, A highly accurate beat frequency fp value is extracted from the observed value ε.

(3) Calculation of distance to target and speed Using the beat frequency fp, the distance and speed are calculated according to the procedure shown in FIG. In addition, about weighting, in addition to -1 or 1, you may multiply weights, such as a tailor weight (refer nonpatent literature 4), in order to reduce a side lobe.

  Although the above processing has been described for the case of two sweeps, it may generally be a case of multiple sweeps. As an example, the case of four sweeps is shown in FIGS. When calculating the speed from the gradient of the beat frequency at four points with respect to the sweep time, linear fitting or the like may be used.

  Moreover, although the case of the phase monopulse on the frequency axis was described as the MRAV technique, a method of obtaining a highly accurate beat frequency by amplitude monopulse calculation (see Non-Patent Document 3) using an adjacent bank may be used.

  Further, the monopulse calculation of the angle axis is performed on the cell detected by the CFAR 34 process using the Σ signal. Further, angle measurement (A36) is performed using Σ and Δ of the beam output, and the Az angle and the EL angle are calculated.

  If there are two reception radar devices (B, C), the same processing is performed for the reception radar devices B and C, and the distances from transmission A to reception A, transmission A to reception B, and transmission A to reception C, respectively. As described above, R1, R12, and R13 can be obtained.

Using this distance, a target position (x, y, z) is calculated as shown in FIG. This method is an intersection of the spherical surface of R1 and the elliptical spherical surfaces of R12 and R13. Among them, the intersection within the predetermined range is calculated with the three-dimensional position calculated from the distance, Az angle, and EL angle observed by the transmission / reception radar apparatus A as the center. If the solution cannot be calculated, the points in the target existence area are divided into (x, y, z) grid points, and the points (x, y, z) at which the values of the following equations are the minimum are calculated at each point. To do.

  When there is one transmission / reception radar apparatus and one reception radar apparatus, the three-dimensional position cannot be specified by two intersecting lines as shown in FIG. In this case, the midpoint of the intersecting line of the receiving radar device is output as the target three-dimensional observation position within the target existence region based on the angle measurement value of the transmitting / receiving radar device.

  Further, in the case of a plurality of radar devices, a radar with a low target SN may be included, and if a three-dimensional position is calculated as it is, a position error may be increased. For this measure, a predetermined threshold is provided for the SN value, and the position is calculated using the value of the radar device above the threshold. For example, as an extreme case, when the SN of only the transmission / reception radar apparatus exceeds the threshold, the three-dimensional position of the transmission / reception radar apparatus is output.

Second Embodiment (Speed output by MRAV)
In the first embodiment, the method for calculating the position has been described. In the present embodiment, a method for calculating the three-dimensional speed with high accuracy will be described. FIG. 10 shows the system, and FIG. 11 shows the processing flow. 10 and 11, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and different parts will be described here.

  The present embodiment is different from the first embodiment in that speed correction is performed in the overall processing apparatus D.

That is, the radial velocity Vr observed from the transmission / reception radar apparatus A and the reception radar apparatuses B and C can be calculated by the MRAV technique (2) and (3) described in the first embodiment. From this speed, when converted to the Doppler frequency, the following equation is obtained.

In the case of bistatic transmission / reception in which transmission and reception are separated from each other, this Doppler signal has the following relationship (see FIG. 12, Non-Patent Document 1).

The expression (7) can be expressed by the following expression when the inner product operation is used as another expression.

When this is expanded to three dimensions with reference to FIG. 13, the following equation is obtained.

  In Equation (9), fb1, fb2, and fb3 are Doppler frequency observation values, and (Rxn, Ryn, Rzn) can be calculated from the radar position and the target observation position, and (Bxn, Byn, Bzn). ) Can be calculated from the radar position and the target observation position.

  Accordingly, there are three unknown variables, the target velocity vector (Vx, Vy, Vz), and the target velocity vector is calculated and output from the equation (9) which is three simultaneous equations.

  Also in the present embodiment, a high-precision target observation speed can be output by providing a threshold for the target observation SN value of each radar device as in the first embodiment.

(Third Embodiment) Time Synchronization and Frequency Tuning In this embodiment, since radar devices are separated from each other, a method of time synchronization adjustment and frequency tuning will be described. The system is shown in FIG. 14, and the processing flow is shown in FIG. 14 and 15, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and different parts will be described here.

  This embodiment differs from the first and second embodiments in that the receiving radar apparatuses B and C include time synchronization control units B310 and C310, and capture the sweep outputs of the Σ series weight multiplication units B32 and C32. To determine the start time of the sweep, and based on the determination result, the start time of the sweep frequency is changed through the timing controllers B23 and C23 provided in the receivers B2 and C2, and the time error is corrected (time synchronization). To do. In FIG. 15, steps SB19 to SB22 and SC19 to SC22 correspond to this. That is, in each of the receiving radar apparatuses B and C, the timing of the sweep reception process (steps SB11 and SC11) is controlled by the PRI time control process (steps SB19 and SC19) and the FFT sampling time is adjusted (steps SB20 and SC20). The end of the PRI time is detected (steps SB21 and SC21), the correction time when the FFT sampling result reaches the maximum amplitude is selected (steps SB22 and SC22), and the FFT processing (steps SB14 and SC22) is performed based on the selection result. The sampling time of SC14) is adjusted.

  The time synchronization process will be described with reference to FIG. In FIG. 16, (a) is a transmission waveform modulated so that up sweep-down sweep is repeated at a constant period, (b1) to (b3) are demodulated waveforms obtained by shifting the reception waveform with respect to (a) by Δt, (c1) ˜ (c3) show peak waveforms of target signals obtained by subjecting the received signals of (b1) ˜ (b3) to FFT processing. As shown in FIG. 16, the signal waveform is described as a continuous waveform of up sweep-down sweep, but it goes without saying that it can be applied only to up sweep or down sweep.

  On the reception radar apparatus side, the transmission waveform of the transmission radar apparatus is known, but a time error occurs even if the time synchronization is adjusted by GPS and an atomic clock. For this reason, synchronized Δtsel is selected based on the maximum value of the target signal after FFT when the start time Δt of the sweep frequency for demodulation is changed in Nt ways.

  Using the selected Δtsel, the processing of the first and second embodiments is performed to calculate the target distance and speed.

(Fourth Embodiment) Center Frequency Correction In the third embodiment, a method for synchronizing time between separated radar apparatuses has been described. This method can be said to be a method of synchronizing the time so that at least reception is possible in the reception radar device located at a position separated from the transmission / reception radar device. In the present embodiment, a technique for improving the accuracy of the center frequency in a receivable situation will be described. The system is shown in FIG. 17, and the processing flow is shown in FIG. The transmission / reception signal waveform is assumed to be an FMCW sweep in which both down sweep and up sweep are continuously transmitted and received.

  17 and 18 differ from FIGS. 14 and 15 in that each of the radar apparatuses A, B, and C bisects the AD conversion output to the Σ system of the signal processors A3, B3, and C3, Weight multipliers A311, B311, C311, FFT processors A312, B312, C312, CFAR detectors A313, B313, C313, correction value calculators A314, B314, and C314 are provided. A transmission modulation unit A23 is provided to modulate the transmission waveform with information of the transmission center frequency, and reception radar devices B23 and C23 are provided with reception demodulation units B23 and C23 using a sweep signal that is a reception local signal similar to the transmission waveform. The received signal is demodulated. Here, weight multipliers A311, B311, C311, FFT processors A312, B312, C312 and CFAR detectors A313, B313, C313 are weight multipliers A32, B32, C32, FFT processors A33, B33, C33, respectively. This is the same as the processing of the CFAR detectors A34, B34, C34. On the other hand, the correction value calculation units A314, B314, and C314 perform processing to correct the beat frequency of the detection target by the CFAR and adjust the center frequencies thereof. FIG. 18 differs in that the beat frequency is corrected for the detection target by the CFAR process in steps SA18, SB18, and SC18.

That is, according to the present embodiment, the beat frequency in the case of FMCW (see Non-Patent Document 5) or FMICW (see Non-Patent Document 6) associates the target beat frequency signal of the down sweep with the up sweep by pairing. And can be expressed as:

The procedure for calculating the error frequency Δferr in equation (10) is as follows.
Procedure 1) Calculate velocity V by MRAV method
Procedure 2) If the velocity V is substituted into the equation (10) and added, the term of the distance R can be deleted. Therefore, Δferr can be calculated by the following equation.

  With this Δferr as a correction value, Δferr is subtracted from the right side of the beat frequency in equation (3), and the MRAV method of the first and second embodiments is applied, thereby calculating a highly accurate distance and speed. it can.

In the above, the case of down sweep and up sweep has been described. However, since this method can be generally applied even when sweep signals having different frequency gradients are used, they are formulated. When expressed using the gradient with respect to the distance R in equation (10), the following equation is obtained.

The calculation method of the error frequency Δferr is the same as that in steps 1 and 2, and when the equation (11) is rewritten, the following equation is obtained.

As a result, the error frequency Δferr corresponding to the center frequency shift can be calculated.

  It is necessary to extract a frequency pair (fbd and fbu or fb1 and fb2) by down sweep and up sweep, or by pairing of target signals between sweeps of different slopes in general. There is a method of pairing those whose values are within a predetermined width using an amplitude value, a measured angle value, or the like.

  Further, the method of the present embodiment requires a signal having at least two different frequency sweep gradients. However, unless the error frequency Δferr is calculated at a predetermined period or the like, only the MRAV is used for at least one sweep signal. A method of calculating the distance and speed by a method such as the above may be used.

(Fifth Embodiment) Frequency Tuning In the fourth embodiment, the technique for correcting the center frequency deviation using the pairing of the beat frequencies of the target signal with different frequency sweep signals has been described. In the present embodiment, a technique for frequency tuning is described by superimposing transmission center frequency information of a transmission / reception radar apparatus on a transmission waveform without using a reflected signal from a target. FIG. 19 shows the system, and FIG. 20 shows the processing flow. 19 and 20 differ from FIGS. 17 and 18 in that the transmission / reception radar apparatus A modulates the transmission waveform according to the information of the transmission center frequency, and the CFAR detection units A34, From the outputs of A313, B34, 313, C34, and C313, the demodulation units A315, A316, B315, B316, C315, and C316 demodulate the information on the transmission center frequency using the sweep signal that is a reception local signal similar to the transmission waveform. The center frequency of the received local signal is corrected using the demodulated transmission center frequency information. In FIG. 20, demodulation processes SA19, SB19, and SC19 correspond to this.

In the above configuration, the processing operation will be described with reference to FIG.
First, in the transmission / reception radar apparatus A, the transmission waveform is modulated by information on the transmission center frequency. As a modulation method, when the sweep waveform is FFTed to a beat frequency, the N-bit code modulation is performed using a high frequency region where no target exists as shown in FIG. When the target maximum distance and maximum speed are set on the beat frequency axis, the maximum value of the beat frequency can be calculated.

  Since the target beat frequency does not exist in the frequency region above the maximum frequency, information such as the transmission center frequency and the beam directing direction can be placed. This has a great merit that the communication line for transmitting necessary information can be minimized. For example, the center frequency, which is expected to change every moment, can be superimposed on the target signal in real time.

  The modulation code is a code obtained by quantizing information such as the center frequency, and is arranged with amplitudes corresponding to 0 and 1 on the frequency axis. When this modulated signal is subjected to inverse FFT, an amplitude waveform for the modulated signal including information on the sweep time is obtained as shown in FIG. Using this modulation signal, amplitude modulation is performed on the frequency sweep signal as shown in FIG. 21C to obtain a modulation signal. The modulated signal is modulated with a carrier signal having a center frequency fc to obtain a transmission waveform.

  A signal reflected from the target and received by the transmission / reception radar apparatus A or the reception radar apparatuses B and C is multiplied by a sweep signal that is a reception local signal similar to the transmission waveform, and the signal having the reception waveform shown in FIG. Then, FFT is performed to obtain the beat frequency. Information modulated as shown in FIG. 21 (e) is also superimposed on the frequency of the target non-existing region of this signal, and the demodulator A315, A316, B315, B316, C315, C316 converts this signal to a predetermined value. Information can be demodulated by setting a threshold to 1 for exceeding and 0 for not exceeding. By using the demodulated information about the transmission center frequency, the correction value calculation units A314, B314, and C314 can correct the center frequency of the received local signal to achieve high-accuracy tuning. If the processing of the first and second embodiments is performed using the tuned signal, the target distance and speed can be output.

(Sixth Embodiment) Improvement of robustness with respect to SN of received signal In the fourth and fifth embodiments, the method for correcting the center frequency has been described. Although these methods can be applied alone, this embodiment describes a method that can improve the robustness of the received signal with respect to the SN and the like using both methods. The system is shown in FIG. 22, and the processing flow is shown in FIG. 22 and 23 differ from FIGS. 19 and 20 in that weighting correction units A317, B317, and C317 are weighted based on the demodulation outputs of the demodulation units A316, B316, and C316 of the radar devices A, B, and C, respectively. By processing, the center frequency of the MRAV processing units A35, B35, and C35 is corrected. In FIG. 23, steps SA20, SB24, and SC24 correspond to this.

That is, in the case where the SN of the beat frequency of the target signal obtained by FFT of the received signal is low, in the method of the fourth embodiment, when pairing the down sweep signal and the up sweep signal, incorrect pairing is performed. there's a possibility that. Further, even when information is modulated as in the fifth embodiment, if the SN is low, it may not be demodulated correctly. For this reason, the correction center frequency is determined by weighting the results of the fourth and fifth embodiments according to the SN of the target beat frequency signal.

  By correcting the center frequency using the integrated center frequency Δfc and applying the first and second embodiments, it is possible to output a target distance and speed with higher accuracy.

  In the above embodiment, the case where there is one transmission / reception radar device and two reception radar devices has been described for the sake of simplicity. However, even when the number of transmission / reception radar devices and reception radar devices is arbitrary, Needless to say, it is good.

  In at least one transmission / reception radar apparatus and Nr (Nr> = 1) reception radar apparatus, the position, transmission beam direction θ, transmission frequency, transmission waveform, etc. of the transmission / reception radar apparatus are communicated to the reception radar apparatus as necessary. Nr having a position different from the value R1 measured by MRAV (Measurement Range After Measurement Velocity) processing by transmitting / receiving at least one continuous wave of up sweep or down sweep having a frequency sweep gradient by a transmission / reception radar device. In the receiving radar apparatus, the intersection point is calculated by N distance differences R1n (n = 1 to Nr) obtained by measuring the distance difference from the transmission position to the target to the reception position by the range axis monopulse. The three-dimensional position (x, y, z) can be calculated with extremely high accuracy.

  In addition, the present embodiment is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS A ... Transmission / reception radar apparatus, A1 ... Antenna, A2 ... Transmission / reception unit, A21 ... Transmission / reception unit, A22 ... Beam control unit, A23 ... Transmission modulation unit, A3 ... Signal processor, A31, A37 ... AD conversion unit, A32, A311 A38: West multiplication unit, A33, A312, A39 ... FFT processing unit, A34, A313 ... CFAR detection unit, A35 ... MRAV processing unit, A36 ... Angle measurement unit, A314 ... Correction value calculation unit, A315, A316 ... Demodulation unit,
B ... reception radar device, B1 ... antenna, B2 ... receiver, B21 ... reception unit, B22 ... beam control unit, B23 ... reception demodulation unit, B3 ... signal processor, B31, B37 ... AD conversion unit, B32, B311 B38 ... West multiplier, B33, B312, B39 ... FFT processor, B310 ... Time synchronization controller, B34, B313 ... CFAR detector, B35 ... MRAV processor, B36 ... Angle measuring unit, B314 ... Correction value calculator, B315, B316 ... demodulator, B317 ... weighting corrector,
C ... reception radar device, C1 ... antenna, C2 ... receiver, C21 ... reception unit, C22 ... beam control unit, C23 ... reception demodulation unit, C3 ... signal processor, C31, C37 ... AD conversion unit, C32, C311 C38: West multiplying unit, C33, C312, C39 ... FFT processing unit, C310 ... Time synchronization control unit, C34, C313 ... CFAR detection unit, C35 ... MRAV processing unit, C36 ... Angle measurement unit, C314 ... Correction value calculation unit, C315, C316 ... demodulator, C317 ... weighting corrector, D ... integrated processing device

Claims (12)

At least one transmission / reception radar apparatus that transmits / receives at least one continuous wave of an up sweep or a down sweep having a frequency sweep gradient as a radar wave;
The transmission / reception radar apparatus is arranged at a position different from the transmission / reception radar apparatus, obtains information on at least the position, transmission beam direction, transmission frequency, transmission waveform of the transmission / reception radar apparatus, and reflects reflected waves of the radar waves transmitted from the transmission / reception radar apparatus Receiving Nr units (Nr ≧ 2 ) of receiving radar devices;
An integrated processing device that integrates the output of the transmission / reception radar device and the output of the reception radar device;
The transmission / reception radar device and the reception radar device each receive a reflected wave of the radar wave and measure a target position by MRAV (Measurement Range After Measurement Velocity) processing,
The integrated processing device has Nr distance differences R1n (n = n = n) obtained by measuring the distance difference from the transmission position of the transmission / reception radar apparatus through the target to the reception position of each of the Nr reception radar apparatuses using a range axis monopulse. 1 to Nr) to calculate an intersection point and calculate a three-dimensional position (x, y, z) of the target. The transmission / reception radar device calculates a velocity V1 corresponding to the target Doppler frequency when the target position is measured by the MRAV processing.
The receiving radar device calculates a velocity V1n (n = 1 to Nr) corresponding to the target Doppler frequency when the target position is measured by the MRAV processing.
The integrated processing device is calculated by the position of the transmission / reception radar device and the reception radar device, the velocity V1 calculated by the transmission / reception radar device and the reception radar device together with the target position (x, y, z). 2. The radar system according to claim 1, wherein a three-dimensional vector of a target speed is output by V1n (n = 1 to Nr).   When the transmission / reception radar apparatus and the reception radar apparatus use FFT (Fast Fourier Transform) for position observation, respectively, select a start time at which the FFT output is maximized when the FFT start time is changed in plural ways, The radar system according to claim 1 or 2, wherein the selected time of disclosure is synchronized, and a frequency shift is calculated and corrected based on a value measured by the MRAV processing and a beat frequency. The transmission / reception radar device transmits / receives continuous waves of at least two or more sweeps having different frequency sweep gradients,
3. The radar system according to claim 1, wherein the receiving radar device corrects a center frequency by calculating a frequency shift based on a value measured by the MRAV process and a beat frequency observed by performing FFT on a target signal. The transmission / reception radar apparatus modulates at least one continuous wave of up sweep or down sweep with the frequency sweep gradient using transmission information including its position, transmission beam direction, transmission frequency, and transmission waveform as a modulation signal, and transmits / receives it. ,
The receiving radar device receives and demodulates a direct wave from the transmitting / receiving radar device or a reflected wave from the target, extracts the transmission information from the demodulated signal, and based on the transmission frequency information therein The radar system according to claim 1 or 2, wherein the frequency is corrected. When the transmission / reception radar apparatus transmits / receives a continuous wave of at least two or more sweeps having different frequency sweep gradients, the frequency sweep uses the transmission information including the position, the transmission beam direction, the transmission frequency, and the transmission waveform as a modulation signal. Modulate at least one continuous wave of up-sweep or down-sweep with a gradient;
The reception radar device demodulates a direct wave from the transmission / reception radar device or a reception wave reflected from a target to extract transmission information, and performs an FFT of the value measured by the MRAV processing and the target signal to observe the beat frequency The radar system according to claim 1 or 2, wherein the calibration is performed by weighting the center frequency by SN (Signal to Noise Ratio). At least one transmission / reception radar device that transmits / receives at least one continuous wave of up sweep or down sweep having a frequency sweep gradient as a radar wave, and the transmission / reception radar device are arranged at different positions, and At least Nr (Nr ≧ 2 ) receiving radar devices that acquire information of at least a position, a transmitting beam direction, a transmitting frequency, and a transmitting waveform and receive a reflected wave of a radar wave transmitted from the transmitting / receiving radar device; Applied to a radar system comprising an apparatus output and an integrated processing device for integrating the output of the receiving radar device;
The transmission / reception radar device and the reception radar device each receive a reflected wave of the radar wave and measure a target position by MRAV (Measurement Range After measurement Velocity) processing,
The distance difference from the transmission position of the transmission / reception radar apparatus to the reception position of each of the Nr reception radar apparatuses via a target is an intersection by Nr distance differences R1n (n = 1 to Nr) measured by a range axis monopulse. And a radar signal processing method of a radar system for calculating the three-dimensional position (x, y, z) of the target. In the transmission / reception radar apparatus, when the target position is measured by the MRAV process, a velocity V1 corresponding to the target Doppler frequency is calculated,
The receiver radar device calculates a velocity V1n (n = 1 to Nr) corresponding to the target Doppler frequency when the target position is measured by the MRAV process.
Along with the target position (x, y, z), the positions of the transmission / reception radar apparatus and the reception radar apparatus, the velocity V1 calculated by the transmission / reception radar apparatus, and V1n (n = 1) calculated by the reception radar apparatus 8. The radar signal processing method of a radar system according to claim 7, wherein a three-dimensional vector of a target speed is output by (Nr).   When using FFT (Fast Fourier Transform) for position observation in each of the transmission / reception radar apparatus and the reception radar apparatus, a start time that maximizes the FFT output when the FFT start time is changed in plural ways is selected. The radar signal processing method for a radar system according to claim 7 or 8, wherein the selected time of disclosure is synchronized, and a frequency shift is calculated and corrected based on a value measured by the MRAV processing and a beat frequency. The transmission / reception radar device transmits and receives continuous waves of at least two sweeps having different frequency sweep gradients,
The radar signal of the radar system according to claim 7 or 8, wherein the receiving radar device calculates a frequency shift based on a beat frequency observed by FFT of the value measured by the MRAV processing and the target signal and corrects the center frequency. Processing method. The transmission / reception radar device modulates at least one continuous wave of up sweep or down sweep with the frequency sweep gradient using transmission information including its position, transmission beam direction, transmission frequency, and transmission waveform as a modulation signal, and transmits and receives And
The receiving radar device receives and demodulates a direct wave from the transmitting / receiving radar device or a reflected wave from the target, extracts the transmission information from the demodulated signal, and based on the information of the transmission frequency therein The radar signal processing method of a radar system according to claim 7 or 8, wherein the center frequency is corrected. When transmitting / receiving continuous waves of at least two or more sweeps having different frequency sweep gradients in the transmission / reception radar apparatus, the transmission information including the position, transmission beam direction, transmission frequency, and transmission waveform is used as a modulation signal. Modulate at least one continuous wave of up sweep or down sweep with a sweep slope,
The receiving radar device demodulates the direct wave from the transmitting / receiving radar device or the received wave reflected from the target to extract transmission information, and the beat frequency observed by FFT of the value measured by the MRAV processing and the target signal The radar signal processing method for a radar system according to claim 7 or 8, wherein the calibration is performed by weighting the center frequency according to the SN (Signal to Noise Ratio).

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