WO2018167952A1 - Adaptive array antenna device - Google Patents
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- WO2018167952A1 WO2018167952A1 PCT/JP2017/010957 JP2017010957W WO2018167952A1 WO 2018167952 A1 WO2018167952 A1 WO 2018167952A1 JP 2017010957 W JP2017010957 W JP 2017010957W WO 2018167952 A1 WO2018167952 A1 WO 2018167952A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/2605—Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
- H01Q3/2611—Means for null steering; Adaptive interference nulling
- H01Q3/2617—Array of identical elements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/36—Means for anti-jamming, e.g. ECCM, i.e. electronic counter-counter measures
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/2605—Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
- H01Q3/2611—Means for null steering; Adaptive interference nulling
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
- H04B7/0842—Weighted combining
- H04B7/0848—Joint weighting
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
- H04B7/0842—Weighted combining
- H04B7/086—Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0868—Hybrid systems, i.e. switching and combining
- H04B7/088—Hybrid systems, i.e. switching and combining using beam selection
Definitions
- the present invention relates to an adaptive array antenna apparatus that multiplies a plurality of signals respectively received by a plurality of subarray antennas by a weighting factor and synthesizes the plurality of signals after the weighting factor multiplication.
- the radar apparatus is mounted on a platform such as an aircraft, and may be operated in an environment where an interference wave arrives.
- the antenna device included in the radar device forms an adaptive beam by an array antenna in which a plurality of subarray antennas are arranged. At this time, the antenna device suppresses the interference wave included in the received signal of the array antenna, and improves the SJNR (Signal to Jamming and Noise Ratio) of the target signal related to the target to be observed.
- the adaptive weight is determined so that a null is formed in the arrival direction of.
- the adaptive weight is a weight coefficient for a plurality of signals respectively received by a plurality of subarray antennas.
- the determination of the adaptive weight by the antenna device is performed by the following method, for example.
- the antenna device temporarily stops a beam transmitted from the array antenna, and uses a plurality of signals respectively received by a plurality of subarray antennas as interference signal during a listening period in which the beam is not transmitted. get.
- the antenna device determines an adaptive weight from the acquired interference wave signal so that a null is formed in the arrival direction of the interference wave.
- the arrival direction of the disturbing wave does not change unless the source of the disturbing wave moves.
- the radar device including the antenna device or the source of the interference wave is moving, the arrival direction of the interference wave changes. For this reason, even if the antenna apparatus determines an adaptive weight in which a null is formed in the arrival direction of the jamming wave during the listening period, the jamming is performed in a short time until the beam transmission is resumed from the array antenna.
- the direction of arrival of waves changes. That is, the arrival direction of the interference wave in the listening period and the arrival direction of the interference wave in the beam transmission period, which is a period in which the beam is transmitted after the listening period ends, are in different directions.
- Non-Patent Document 1 discloses an antenna device that performs a process of widening a null formed by an adaptive weight determined during a listening period in order to avoid the influence of a null shift.
- the conventional antenna apparatus performs a process of expanding the width of the null formed by the adaptive weight, but does not appropriately set the extension width of the null width based on the change in the arrival direction of the disturbing wave. For this reason, a large change may occur in which the arrival direction of the interference wave exceeds the widened null width. Thus, when the change of the arrival direction of the jamming wave is large, there is a problem that the jamming wave included in the received signal of the array antenna cannot be suppressed.
- the present invention has been made to solve the above-described problems, and an antenna device capable of suppressing the interference wave included in the received signal of the array antenna even if the arrival direction of the interference wave greatly changes.
- the purpose is to obtain.
- the antenna device includes an array antenna in which a plurality of subarray antennas including one or more element antennas are arranged, and a plurality of subarray antennas during a listening period in which a beam is not transmitted from the array antenna. Interference waves in the listening period from a plurality of signals received respectively and a plurality of signals respectively received by a plurality of subarray antennas during a beam transmission period in which a beam is transmitted after the end of the listening period.
- a null shift estimation unit that estimates a null shift, which is a change between the arrival direction of the interference wave and the arrival direction of the jamming wave in the beam transmission period, and a plurality of null shift estimations based on the null shift estimated by the null shift estimation unit.
- a compensation weight calculating unit that calculates a compensation weight for compensating for the null shift, and the beam forming unit applies a plurality of signals respectively received by the plurality of subarray antennas during the beam transmission period to the compensation weight calculating unit.
- the calculated compensation weights are multiplied to synthesize a plurality of signals after the compensation weight multiplication.
- the interference in the listening period from the plurality of signals respectively received by the plurality of subarray antennas during the listening period and the plurality of signals respectively received by the plurality of subarray antennas during the beam transmission period.
- a null shift estimation unit that estimates a null shift that is a change between the arrival direction of the wave and the arrival direction of the disturbing wave in the beam transmission period, and the compensation weight calculation unit is based on the null shift estimated by the null shift estimation unit.
- the compensation weight for compensating for the null shift is calculated as the weighting factor for the plurality of signals respectively received by the plurality of subarray antennas, the arrival direction of the interference wave greatly changes. Also has the effect of suppressing interfering waves contained in the received signal of the array antenna
- FIG. 1 is a block diagram showing an adaptive array antenna apparatus according to Embodiment 1 of the present invention.
- FIG. 2 is a hardware configuration diagram showing the signal processing device 2 of the adaptive array antenna device according to Embodiment 1 of the present invention.
- the subarray antenna 1-m is an antenna including at least one element antenna.
- the signal processing device 2 includes a null shift estimation unit 11, a compensation weight calculation unit 12, and a beam forming unit 13, and multiplies a plurality of signals respectively received by the M subarray antennas 1-m by weighting factors.
- FIG. 1 for simplification of the drawing, a receiver for detecting a signal received by the subarray antenna 1-m, a converter for converting the received signal of the receiver from an analog signal to a digital signal, and the like are omitted. Actually, a receiver and a converter are provided. For this reason, the null shift estimation unit 11 and the beam forming unit 13 are given digital received signals corresponding to the signals received by the M subarray antennas 1-m.
- a received signal vector including M digital received signals is shown.
- the null shift estimation unit 11 is realized by, for example, a null shift estimation circuit 21 shown in FIG.
- the null shift estimation unit 11 receives M digital received signals corresponding to M signals respectively received by the M subarray antennas 1-m during a listening period in which a beam is not transmitted from the array antenna 1. get.
- the null shift estimation unit 11 corresponds to the M signals respectively received by the M subarray antennas 1-m during the beam transmission period, which is a period during which the beam after the listening period ends is transmitted.
- M digital received signals are acquired.
- the null shift estimation unit 11 uses the M digital reception signals during the listening period and the M digital reception signals during the beam transmission period, and the arrival direction of the interference wave during the listening period and the arrival of the interference wave during the beam transmission period.
- the process which estimates the null shift which is a change with a direction is implemented.
- the beam transmission period includes a period in which the array antenna 1 receives a beam in addition to a period in which the array antenna 1 transmits a beam.
- the compensation weight calculation unit 12 is realized by, for example, a compensation weight calculation circuit 22 illustrated in FIG. Based on the null shift estimated by the null shift estimation unit 11, the compensation weight calculation unit 12 receives M signals corresponding to M signals respectively received by the M subarray antennas 1-m during the beam transmission period. As a weighting factor for the digital received signal, a process of calculating a compensation weight for compensating for a null shift is performed.
- the beam forming unit 13 is realized by, for example, a beam forming circuit 23 shown in FIG.
- the beam forming unit 13 includes M multipliers 14-m and adders 15, and M corresponding to M signals respectively received by the M subarray antennas 1-m during the beam transmission period.
- a process of multiplying the digital reception signals by the compensation weight calculated by the compensation weight calculation unit 12 and combining the M digital reception signals after the compensation weight multiplication is performed.
- the multiplier 14-m multiplies the digital reception signal corresponding to the signal received by the sub-array antenna 1-m during the beam transmission period by the compensation weight calculated by the compensation weight calculation unit 12, and after the compensation weight multiplication.
- the digital reception signal is output to the adder 15.
- the adder 15 combines the digital reception signals after multiplication of the M compensation weights output from the M multipliers 14-m, and outputs the combined digital reception signal as a reception beam.
- each of the null shift estimation unit 11, the compensation weight calculation unit 12, and the beam forming unit 13, which are components of the signal processing device 2, is realized by dedicated hardware as shown in FIG. is doing. That is, what is realized by the null shift estimation circuit 21, the compensation weight calculation circuit 22, and the beam forming circuit 23 is assumed.
- the null shift estimation circuit 21, the compensation weight calculation circuit 22, and the beam forming circuit 23 are, for example, a single circuit, a composite circuit, a programmed processor, a processor programmed in parallel, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-). Programmable Gate Array) or a combination thereof.
- the components of the signal processing device 2 are not limited to those realized by dedicated hardware, and the signal processing device 2 is realized by software, firmware, or a combination of software and firmware. May be.
- Software or firmware is stored as a program in the memory of a computer.
- the computer means hardware that executes a program, and includes, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, a DSP (Digital Signal Processor), and the like. .
- FIG. 3 is a hardware configuration diagram of a computer when the signal processing device 2 is realized by software or firmware.
- a program for causing the computer to execute the processing procedures of the null shift estimation unit 11, the compensation weight calculation unit 12, and the beam forming unit 13 is stored in the memory 31 of the computer.
- the computer processor 32 may execute a program stored in the memory 31.
- FIG. 6 is a flowchart showing a processing procedure when the signal processing device 2 is realized by software or firmware.
- the memory 31 of the computer is, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory Memory, or an EEPROM (Electrically Erasable Memory).
- a volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), and the like are applicable.
- FIG. 4 is a block diagram showing a null shift estimation unit 11 of the adaptive array antenna apparatus according to Embodiment 1 of the present invention.
- the first correlation matrix calculation unit 41 calculates the interference wave from M digital received signals corresponding to M signals respectively received by the M subarray antennas 1-m during the listening period. A process of calculating a correlation matrix is performed.
- the vector calculation unit 42 scans the scanning direction of the interference wave using the weight constraint vector for scanning the main beam direction of the beam and the interference matrix of the interference wave calculated by the first correlation matrix calculation unit 41.
- a process of calculating a weight vector for performing is performed. That is, the vector calculation unit 42 is a diagonal matrix having a path difference phase component due to the difference between the main beam direction and the scan direction in the diagonal terms, the weight constraint vector, and the disturbance calculated by the first correlation matrix calculation unit 41.
- a process of calculating a weight vector is performed by multiplying the wave correlation matrix.
- the second correlation matrix calculation unit 43 receives the received signal of the array antenna 1 from the M digital received signals corresponding to the M signals respectively received by the M subarray antennas 1-m during the beam transmission period. The process which calculates the correlation matrix of is implemented.
- the evaluation function calculation unit 44 uses the weight vector calculated by the vector calculation unit 42 and the correlation matrix of the received signal calculated by the second correlation matrix calculation unit 43 to calculate an evaluation function used for estimation of the null shift. Perform the calculation process.
- the null deviation estimation processing unit 45 uses the evaluation function calculated by the evaluation function calculation unit 44 to perform processing for estimating a null deviation.
- FIG. 5 is a block diagram showing the compensation weight calculation unit 12 of the adaptive array antenna apparatus according to Embodiment 1 of the present invention.
- the CMT matrix calculation unit 51 calculates a CMT (Covariance Matrix Tape) matrix that is a matrix for setting a null width from the null shift estimated by the null shift estimation processing unit 45 of the null shift estimation unit 11.
- the weight calculation processing unit 52 includes a compensation type correlation matrix calculation unit 53 and a compensation type weight calculation unit 54.
- the weight calculation processing unit 52 compensates for the null shift from the CMT matrix calculated by the CMT matrix calculation unit 51 and the interference matrix correlation matrix calculated by the first correlation matrix calculation unit 41 of the null shift estimation unit 11. The process which calculates the compensation weight to perform is implemented.
- the compensation type correlation matrix calculation unit 53 calculates a null shift from the CMT matrix calculated by the CMT matrix calculation unit 51 and the interference matrix correlation matrix calculated by the first correlation matrix calculation unit 41 of the null shift estimation unit 11. A process of calculating a compensation type correlation matrix is performed.
- the compensation weight calculation unit 54 performs a process of calculating a compensation weight for compensating for the null shift from the weight constraint vector and the null shift compensation correlation matrix calculated by the compensation correlation matrix calculation unit 53.
- the signal processing device 2 detects M signals respectively received by the M subarray antennas 1-m, and converts each of the detected M signals from analog signals to digital signals.
- the null shift estimation unit 11 and the beam forming unit 13 of the signal processing device 2 are provided with a received signal vector including digital received signals that are M digital signals that have been converted.
- a received signal vector x 0 (t) shown in the following equation (1) is given to the null shift estimating unit 11 and the beam forming unit 13.
- t is time
- a J (u 0 (k) ) is the arrival direction
- u 0 (k) [u 0 (k) , v 0 (k) ] T
- T is a symbol indicating transposition
- j k (t) is the complex amplitude of the k-th jamming wave
- n 0 (t) is the receiver noise vector.
- the reception signal during the listening period is represented by the following equation (2).
- the interference matrix correlation matrix R 0 is calculated from the vector x 0 (t) (step ST1 in FIG. 6).
- E [•] is a symbol indicating an ensemble average with respect to •.
- H is a symbol indicating Hermitian transposition.
- a finite number of received signal vectors x 0 (t) at different times t in the listening period are used.
- the first correlation matrix calculator 41 outputs the calculated interference matrix correlation matrix R 0 to the vector calculator 42 and the compensation-type correlation matrix calculator 53 of the compensation weight calculator 12.
- Vector calculating unit 42 obtains the scan direction u of the disturbance, determining the scanning direction u and the main beam direction u s difference diagonal matrix having a path difference phase component in the diagonal section by D of (u-u s) .
- the main beam direction u s is in the beam transmission period after the listening period ends, the direction of the main beam in the beam transmitted from the array antenna 1.
- the vector calculation unit 42 obtained during beam transmission period after the listening period has ended, the wait constraint vector a to scan the main beam direction u s of the beam transmitted from the array antenna 1 (u s) To do.
- the vector calculation unit 42 is output from the diagonal matrix D (u ⁇ u s ), the weight constraint vector a (u s ), and the first correlation matrix calculation unit 41 as shown in the following equation (3).
- the weight vector w (u) for scanning the scanning direction u of the interference wave is calculated by multiplying the interference wave correlation matrix R 0 (step ST2 in FIG. 6).
- ⁇ is a normalization coefficient set in advance.
- the vector calculation unit 42 outputs the calculated weight vector w (u) to the evaluation function calculation unit 44.
- a received signal vector x (t) shown in the following equation (4) is given to the null shift estimation unit 11 and the beam forming unit 13.
- s (t) is the target signal
- a s is the steering vector for the direction of arrival of the target signal s (t)
- n (t ) is the receiver noise vector
- receiver noise vector n The characteristics of t) are the same as the characteristics of the receiver noise vector n 0 (t) during the listening period.
- u 0 (k) + ⁇ u k is the arrival direction of the k-th jamming wave in the beam transmission period, and is shifted from the arrival direction of the k-th jamming wave in the listening period.
- ⁇ u k [ ⁇ u k , ⁇ v k ] T is the difference between the arrival direction of the kth jamming wave in the beam transmission period and the arrival direction of the kth jamming wave in the listening period.
- the second correlation matrix calculation unit 43 of the null shift estimation unit 11 is given the received signal vector x (t) during the beam transmission period after the end of the listening period, as shown in the following equation (5).
- the correlation matrix R x of the received signal of the array antenna 1 is calculated from the received signal vector x (t) during the beam transmission period (step ST3 in FIG. 6).
- the second correlation matrix calculation unit 43 outputs the calculated correlation matrix R x of the received signal to the evaluation function calculation unit 44.
- the evaluation function calculation unit 44 of the null shift estimation unit 11 calculates the weight vector w (u) output from the vector calculation unit 42 and the correlation matrix R x of the reception signal output from the second correlation matrix calculation unit 43.
- an evaluation function P (u) used for estimation of null shift is calculated (step ST4 in FIG. 6).
- W H (u) R x w (u) which is the denominator of Equation (6), is the scanning output power of the beam by the weight vector w (u).
- the weight vector w (u) is a weight vector for scanning the weight vector w (u s ) in the main beam direction u s in the interference wave scanning direction u, and thus the weight vector w (u).
- the null for the direction of arrival u of the jamming wave formed by is also scanned.
- the weight vector w (u), the scanning direction u is if u s + .delta.u k, to form a null in the direction of u 0 (k) + ⁇ u k .
- This null the formation direction u 0 (k) + ⁇ u k coincides with the arrival direction u 0 (k) + ⁇ u k of the k-th interference wave contained in the correlation matrix R x of the received signal, w H (u s + ⁇ u k) R x w (u s + ⁇ u k) of the k-th included in the interference wave power is minimized.
- the evaluation function calculation unit 44 outputs the calculated evaluation function P (u) to the null deviation estimation processing unit 45.
- the null deviation estimation processing unit 45 of the null deviation estimation unit 11 estimates the null deviation using the evaluation function P (u) output from the evaluation function calculation unit 44, and calculates the compensation value of the estimated null deviation value ⁇ u hat. It outputs to the part 12 (step ST5 of FIG. 6).
- the vector calculation unit 42 may calculate the weight vector w (u) for scanning the scanning direction u of the interference wave by the following equation (7) instead of the equation (3).
- D ⁇ is a diagonal matrix having a difference beam forming taper in the diagonal terms.
- w (u) is a weight vector forming a null in an arrival direction u and the main beam direction u s jammer.
- target signal coming from the vicinity of the main beam direction u s is suppressed, it is included in w H (u s + ⁇ u k ) R x w (u s + ⁇ u k) The power of the target signal is reduced.
- u corresponding to the peak function value is a candidate for null shift
- the peak function value ⁇ u corresponding to u is the null deviation estimated value ⁇ u hat.
- the CMT matrix T CMT for setting the null width is calculated using the estimated null deviation estimated value ⁇ u hat (step ST6 in FIG. 6).
- the set null width ⁇ u based on the CMT matrix T CMT is determined as shown in the following formula (9) based on the null deviation estimated value ⁇ u hat.
- k u and k v are arbitrary coefficients, and are values set in advance according to the taper used in beam forming, regardless of the estimated null shift estimated value ⁇ u hat.
- the CMT matrix calculation unit 51 outputs the calculated CMT matrix T CMT to the compensation type correlation matrix calculation unit 53.
- a null shift compensation type correlation matrix R is calculated from the interference matrix correlation matrix R0 output from the correlation matrix calculation unit 41 (step ST7 in FIG. 6).
- a double circle symbol is a symbol indicating a Hadamard product that performs multiplication of matrix elements of the CMT matrix T CMT and the correlation matrix R 0 of the interference wave.
- the compensation type correlation matrix calculation unit 53 outputs the calculated null shift compensation type correlation matrix R to the compensation type weight calculation unit 54.
- the compensation weight calculation unit 54 uses the weight constraint vector a (u s ) and the null deviation compensation type correlation matrix R output from the compensation type correlation matrix calculation unit 53 as shown in the following equation (11). Then, a compensation weight vector w A indicating a compensation weight for compensating for the null shift is calculated (step ST8 in FIG. 6).
- ⁇ is a normalization coefficient.
- the compensation weight calculation unit 54 outputs the calculated compensation weight vector w A to the beam forming unit 13.
- the beam forming unit 13 compensates the reception signal vector x (t) as shown in the following equation (12).
- a reception beam y (t) is calculated by multiplying the weight vector w A and combining the reception signal vector x (t) after the compensation weight multiplication (step ST9 in FIG. 6).
- the M multipliers 14-m in the beam forming unit 13 are included in the compensation weight vector w A in the digital reception signal related to the subarray antenna 1-m included in the reception signal vector x (t).
- the compensation weights related to the sub-array antenna 1 -m are multiplied, and the digital received signal after the compensation weight multiplication is output to the adder 15.
- the adder 15 of the beam forming unit 13 combines the M digital reception signals output from the M multipliers 14-m, and outputs the combined digital reception signal as a reception beam y (t).
- reception signal vector x (t) is multiplied by the compensation weight vector w A , a null having a set null width ⁇ u is formed in the reception beam y (t) with the arrival direction u 0 of the disturbing wave as the center. ing.
- a plurality of signals respectively received by the M subarray antennas 1-m during the listening period and M subarray antennas during the beam transmission period a null shift estimation unit 11 that estimates a null shift, which is a change between the arrival direction of the interference wave in the listening period and the arrival direction of the interference wave in the beam transmission period, from the plurality of signals respectively received by 1-m;
- the compensation weight calculation unit 12 uses a null coefficient as a weighting factor for a plurality of signals respectively received by the M subarray antennas 1-m during the beam transmission period. Since the compensation weight for compensating for the deviation is calculated, the array antenna 1 can be used even if the arrival direction of the disturbing wave changes greatly. An effect that can suppress interference waves in the received signal.
- the compensation weight calculation unit 12 includes the CMT matrix calculation unit 51, and uses the CMT matrix T CMT calculated by the CMT matrix calculation unit 51 to provide a compensation weight indicating a compensation weight for compensating for a null shift.
- An example of calculating the vector w A is shown.
- the compensation weight calculation unit 12 calculates a compensation weight vector w A indicating a compensation weight for compensating for a null shift without using the CMT matrix TCMT .
- FIG. 7 is a block diagram showing a compensation weight calculation unit 12 of the adaptive array antenna apparatus according to Embodiment 2 of the present invention.
- the weight calculation processing unit 55 includes a compensation type correlation matrix calculation unit 56 and a compensation type weight calculation unit 54.
- the compensation-type correlation matrix calculation unit 56 calculates the null shift estimated by the null shift estimation processing unit 45 of the null shift estimation unit 11 and the interference wave calculated by the first correlation matrix calculation unit 41 of the null shift estimation unit 11. A process of calculating a null shift compensation type correlation matrix is performed from the correlation matrix.
- ⁇ u k [ ⁇ u k , ⁇ v k ] T.
- the received signal vector x (t) shown in the following equation (13) is converted to the null shift estimation unit 11 and the beam forming unit 13.
- u 0 (k) + ⁇ u is the arrival direction of the kth jamming wave in the beam transmission period, and is shifted from the arrival direction of the kth jamming wave in the listening period.
- the second correlation matrix calculation unit 43 of the null shift estimation unit 11 is given the beam transmission as in the first embodiment when the reception signal vector x (t) during the beam transmission period shown in the equation (13) is given.
- a correlation matrix R x of the reception signal of the array antenna 1 is calculated from the reception signal vector x (t) during the period.
- the second correlation matrix calculation unit 43 outputs the calculated correlation matrix R x of the received signal to the evaluation function calculation unit 44.
- the evaluation function calculation unit 44 of the null shift estimation unit 11 calculates the weight vector w (u) output from the vector calculation unit 42 and the correlation matrix R x of the reception signal output from the second correlation matrix calculation unit 43.
- the evaluation function P (u) used for estimating the null shift is calculated.
- W H (u) R x w (u) which is the denominator of Equation (6), is the scanning output power of the beam by the weight vector w (u).
- the weight vector w (u) is a weight vector for scanning the weight vector w (u s ) in the main beam direction u s in the interference wave scanning direction u, and thus the weight vector w (u).
- the null for the direction of arrival u of the jamming wave formed by is also scanned.
- the weight vector w (u) forms a null in the direction of u 0 (k) + ⁇ u if the scan direction u is u s + ⁇ u. Since the direction u 0 (k) + ⁇ u forming this null coincides with the arrival direction u 0 (k) + ⁇ u of the k-th jamming wave included in the correlation matrix R x of the received signal, w H (u s + .delta.u) power R x w (u s + ⁇ u k-th interference wave contained in) is minimized.
- the estimated value is ⁇ u hat.
- the evaluation function calculation unit 44 outputs the calculated evaluation function P (u) to the null deviation estimation processing unit 45.
- the null deviation estimation processing unit 45 of the null deviation estimation unit 11 estimates the null deviation by using the evaluation function P (u) output from the evaluation function calculation unit 44, as in the first embodiment, and the null deviation. Is output to the compensation weight calculation unit 12.
- the compensation-type correlation matrix calculation unit 56 of the compensation weight calculation unit 12 outputs the null shift estimated value ⁇ u hat output from the null shift estimation processing unit 45 of the null shift estimation unit 11 and the first correlation matrix calculation unit 41.
- a null shift compensation type correlation matrix R 0 ′ is calculated from the correlation matrix R 0 of the disturbed wave.
- the compensation type correlation matrix calculation unit 56 outputs the calculated null shift compensation type correlation matrix R 0 ′ to the compensation type weight calculation unit 54.
- the interference matrix correlation matrix R 0 calculated by the first correlation matrix calculator 41 can be expressed as the following Expression (14).
- a 0 is a matrix in which K steering vectors a J (u 0 (k) ) are arranged, J is a correlation matrix of j k (t), and ⁇ 2 is receiver noise power.
- the interference matrix R 0 ′ of the interference wave during the beam transmission period can be expressed as the following equation (15).
- the interference matrix correlation matrix R 0 ′ during the beam transmission period corresponds to a null shift compensation correlation matrix.
- a 0 ′ is a matrix in which K steering vectors a J (u 0 (k) + ⁇ u) are arranged.
- the compensation weight calculation unit 54 calculates the weight constraint vector a (u s ) and the null deviation compensation correlation matrix R 0 ′ output from the compensation correlation matrix calculation unit 53 as shown in the following equation (19). Using this, a compensation weight vector w A indicating a compensation weight for compensating for the null shift is calculated.
- the compensation weight calculation unit 54 outputs the calculated compensation weight vector w A to the beam forming unit 13.
- the beam forming unit 13 adds the compensation weight vector to the reception signal vector x (t) as in the first embodiment.
- the reception beam y (t) is calculated by multiplying w A and synthesizing the reception signal vector x (t) after the compensation weight multiplication. Since the reception signal vector x (t) is multiplied by the compensation weight vector w A , a null having a set null width ⁇ u is formed in the reception beam y (t) with the arrival direction u 0 of the disturbing wave as the center. ing.
- the present invention is suitable for an adaptive array antenna apparatus that multiplies a plurality of signals received by a plurality of subarray antennas by a weighting factor and synthesizes the plurality of signals after the weighting factor multiplication.
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Abstract
Description
レーダ装置が備えるアンテナ装置は、複数のサブアレーアンテナが並べられているアレーアンテナによってアダプティブビームを形成する。
このとき、アンテナ装置は、アレーアンテナの受信信号に含まれている妨害波を抑圧して、観測対象の目標に係る目標信号のSJNR(Signal to Jamming and Noise Ratio)を改善するために、妨害波の到来方向にヌルが形成されるように、アダプティブウェイトを決定する。アダプティブウェイトは、複数のサブアレーアンテナによりそれぞれ受信される複数の信号に対する重み係数である。 The radar apparatus is mounted on a platform such as an aircraft, and may be operated in an environment where an interference wave arrives.
The antenna device included in the radar device forms an adaptive beam by an array antenna in which a plurality of subarray antennas are arranged.
At this time, the antenna device suppresses the interference wave included in the received signal of the array antenna, and improves the SJNR (Signal to Jamming and Noise Ratio) of the target signal related to the target to be observed. The adaptive weight is determined so that a null is formed in the arrival direction of. The adaptive weight is a weight coefficient for a plurality of signals respectively received by a plurality of subarray antennas.
まず、アンテナ装置は、アレーアンテナから送信されるビームを一時的に止めて、ビームが送信されない期間であるリスニング期間中に、複数のサブアレーアンテナによりそれぞれ受信された複数の信号を妨害波の信号として取得する。
次に、アンテナ装置は、取得した妨害波の信号から、妨害波の到来方向にヌルが形成されるように、アダプティブウェイトを決定する。 The determination of the adaptive weight by the antenna device is performed by the following method, for example.
First, the antenna device temporarily stops a beam transmitted from the array antenna, and uses a plurality of signals respectively received by a plurality of subarray antennas as interference signal during a listening period in which the beam is not transmitted. get.
Next, the antenna device determines an adaptive weight from the acquired interference wave signal so that a null is formed in the arrival direction of the interference wave.
しかし、アンテナ装置を備えるレーダ装置又は妨害波の発信源が移動している場合には、妨害波の到来方向が変化する。
このため、アンテナ装置が、リスニング期間中に、妨害波の到来方向にヌルが形成されるアダプティブウェイトを決定しても、アレーアンテナからビームの送信が再開されるまでの僅かな時間中に、妨害波の到来方向が変化する。
即ち、リスニング期間における妨害波の到来方向と、リスニング期間が終了した後に、ビームが送信される期間であるビーム送信期間における妨害波の到来方向とが、異なる方向になってしまう。 When a radar device including an antenna device is installed at a land base or the like and the radar device does not move, the arrival direction of the disturbing wave does not change unless the source of the disturbing wave moves.
However, when the radar device including the antenna device or the source of the interference wave is moving, the arrival direction of the interference wave changes.
For this reason, even if the antenna apparatus determines an adaptive weight in which a null is formed in the arrival direction of the jamming wave during the listening period, the jamming is performed in a short time until the beam transmission is resumed from the array antenna. The direction of arrival of waves changes.
That is, the arrival direction of the interference wave in the listening period and the arrival direction of the interference wave in the beam transmission period, which is a period in which the beam is transmitted after the listening period ends, are in different directions.
ヌルずれが生じることで、アンテナ装置による妨害波の抑圧性能が劣化するため、レーダ装置による目標の検出性能が劣化する。
以下の非特許文献1には、ヌルずれの影響を回避するため、リスニング期間中に決定したアダプティブウェイトによって形成されるヌルの幅を広げる処理を行うアンテナ装置が開示されている。 Due to the change in the direction of arrival of the jamming wave, there is a shift between the direction of the null formed by the adaptive weight determined during the listening period and the actual direction of arrival of the jamming wave during the beam transmission period (hereinafter referred to as “null shift” ").
When the null shift occurs, the interference wave suppression performance of the antenna device deteriorates, and thus the target detection performance of the radar device deteriorates.
Non-Patent
図1は、この発明の実施の形態1によるアダプティブアレーアンテナ装置を示す構成図である。
図2は、この発明の実施の形態1によるアダプティブアレーアンテナ装置の信号処理装置2を示すハードウェア構成図である。
図1及び図2において、アレーアンテナ1は、M個のサブアレーアンテナ1-m(m=1,2,・・・,M)が並べられているアンテナである。
サブアレーアンテナ1-mは、少なくとも1つ以上の素子アンテナを含んでいるアンテナである。
1 is a block diagram showing an adaptive array antenna apparatus according to
FIG. 2 is a hardware configuration diagram showing the
1 and 2, an
The subarray antenna 1-m is an antenna including at least one element antenna.
図1では、図面の簡単化のため、サブアレーアンテナ1-mにより受信された信号を検波する受信機及び受信機の受信信号をアナログ信号からデジタル信号に変換する変換器などを省略しているが、実際には、受信機及び変換器などを備えている。
このため、ヌルずれ推定部11及びビーム形成部13には、M個のサブアレーアンテナ1-mにより受信された信号に対応するデジタル受信信号が与えられる。
図1では、M個のデジタル受信信号を含んでいる受信信号ベクトルが表記されている。 The
In FIG. 1, for simplification of the drawing, a receiver for detecting a signal received by the subarray antenna 1-m, a converter for converting the received signal of the receiver from an analog signal to a digital signal, and the like are omitted. Actually, a receiver and a converter are provided.
For this reason, the null
In FIG. 1, a received signal vector including M digital received signals is shown.
ヌルずれ推定部11は、アレーアンテナ1からビームが送信されない期間であるリスニング期間中に、M個のサブアレーアンテナ1-mによりそれぞれ受信されたM個の信号に対応するM個のデジタル受信信号を取得する。
また、ヌルずれ推定部11は、リスニング期間が終了した後のビームが送信される期間であるビーム送信期間中に、M個のサブアレーアンテナ1-mによりそれぞれ受信されたM個の信号に対応するM個のデジタル受信信号を取得する。
ヌルずれ推定部11は、リスニング期間中のM個のデジタル受信信号と、ビーム送信期間中のM個のデジタル受信信号とから、リスニング期間における妨害波の到来方向とビーム送信期間における妨害波の到来方向との変化であるヌルずれを推定する処理を実施する。
なお、ビーム送信期間には、アレーアンテナ1がビームを送信する期間のほか、アレーアンテナ1がビームを受信する期間が含まれている。 The null
The null
Also, the null
The null
The beam transmission period includes a period in which the
補償ウェイト算出部12は、ヌルずれ推定部11により推定されたヌルずれに基づいて、ビーム送信期間中に、M個のサブアレーアンテナ1-mによりそれぞれ受信されたM個の信号に対応するM個のデジタル受信信号に対する重み係数として、ヌルずれを補償する補償ウェイトを算出する処理を実施する。 The compensation
Based on the null shift estimated by the null
ビーム形成部13は、M個の乗算器14-m及び加算器15を備えており、ビーム送信期間中に、M個のサブアレーアンテナ1-mによりそれぞれ受信されたM個の信号に対応するM個のデジタル受信信号に補償ウェイト算出部12により算出された補償ウェイトを乗算し、補償ウェイト乗算後のM個のデジタル受信信号を合成する処理を実施する。
乗算器14-mは、ビーム送信期間中に、サブアレーアンテナ1-mにより受信された信号に対応するデジタル受信信号に補償ウェイト算出部12により算出された補償ウェイトを乗算し、補償ウェイト乗算後のデジタル受信信号を加算器15に出力する。
加算器15は、M個の乗算器14-mからそれぞれ出力されたM個の補償ウェイト乗算後のデジタル受信信号を合成し、合成後のデジタル受信信号を受信ビームとして出力する。 The
The
The multiplier 14-m multiplies the digital reception signal corresponding to the signal received by the sub-array antenna 1-m during the beam transmission period by the compensation weight calculated by the compensation
The
ヌルずれ推定回路21、補償ウェイト算出回路22及びビーム形成回路23は、例えば、単一回路、複合回路、プログラム化したプロセッサ、並列プログラム化したプロセッサ、ASIC(Application Specific Integrated Circuit)、FPGA(Field-Programmable Gate Array)、または、これらを組み合わせたものが該当する。 In FIG. 1, it is assumed that each of the null
The null
ソフトウェア又はファームウェアはプログラムとして、コンピュータのメモリに格納される。コンピュータは、プログラムを実行するハードウェアを意味し、例えば、CPU(Central Processing Unit)、中央処理装置、処理装置、演算装置、マイクロプロセッサ、マイクロコンピュータ、プロセッサ、DSP(Digital Signal Processor)などが該当する。 However, the components of the
Software or firmware is stored as a program in the memory of a computer. The computer means hardware that executes a program, and includes, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, a DSP (Digital Signal Processor), and the like. .
信号処理装置2がソフトウェア又はファームウェアなどで実現される場合、ヌルずれ推定部11、補償ウェイト算出部12及びビーム形成部13の処理手順をコンピュータに実行させるためのプログラムをコンピュータのメモリ31に格納し、コンピュータのプロセッサ32がメモリ31に格納されているプログラムを実行するようにすればよい。
図6は、信号処理装置2がソフトウェア又はファームウェアなどで実現される場合の処理手順を示すフローチャートである。
なお、コンピュータのメモリ31は、例えば、RAM(Random Access Memory)、ROM(Read Only Memory)、フラッシュメモリ、EPROM(Erasable Programmable Read Only Memory)、EEPROM(Electrically Erasable Programmable Read Only Memory)などの不揮発性又は揮発性の半導体メモリや、磁気ディスク、フレキシブルディスク、光ディスク、コンパクトディスク、ミニディスク、DVD(Digital Versatile Disc)などが該当する。 FIG. 3 is a hardware configuration diagram of a computer when the
When the
FIG. 6 is a flowchart showing a processing procedure when the
The
図4において、第1の相関行列算出部41は、リスニング期間中に、M個のサブアレーアンテナ1-mによりそれぞれ受信されたM個の信号に対応するM個のデジタル受信信号から、妨害波の相関行列を算出する処理を実施する。 FIG. 4 is a block diagram showing a null
In FIG. 4, the first correlation
即ち、ベクトル算出部42は、メインビーム方向とスキャン方向の差による行路差位相成分を対角項に有する対角行列と、ウェイト拘束ベクトルと、第1の相関行列算出部41により算出された妨害波の相関行列とを乗算することで、ウェイトベクトルを算出する処理を実施する。
第2の相関行列算出部43は、ビーム送信期間中に、M個のサブアレーアンテナ1-mによりそれぞれ受信されたM個の信号に対応するM個のデジタル受信信号から、アレーアンテナ1の受信信号の相関行列を算出する処理を実施する。 The
That is, the
The second correlation
ヌルずれ推定処理部45は、評価関数算出部44により算出された評価関数を用いて、ヌルずれを推定する処理を実施する。 The evaluation
The null deviation
図5において、CMT行列算出部51は、ヌルずれ推定部11のヌルずれ推定処理部45により推定されたヌルずれから、ヌル幅を設定する行列であるCMT(Covariance Matrix Taper)行列を算出する処理を実施する。
ウェイト算出処理部52は、補償型相関行列算出部53及び補償型ウェイト算出部54を備えている。
ウェイト算出処理部52は、CMT行列算出部51により算出されたCMT行列と、ヌルずれ推定部11の第1の相関行列算出部41により算出された妨害波の相関行列とから、ヌルずれを補償する補償ウェイトを算出する処理を実施する。 FIG. 5 is a block diagram showing the compensation
In FIG. 5, the CMT
The weight
The weight
補償型ウェイト算出部54は、ウェイト拘束ベクトルと補償型相関行列算出部53により算出されたヌルずれ補償型相関行列とから、ヌルずれを補償する補償ウェイトを算出する処理を実施する。 The compensation type correlation
The compensation
まず、信号処理装置2は、アレーアンテナ1から送信されるビームを一時的に止めて、ビームが送信されない期間であるリスニング期間中に、M個のサブアレーアンテナ1-m(m=1,2,・・・,M)によりそれぞれ受信されたM個の信号を妨害波の信号として取得する。
信号処理装置2は、M個のサブアレーアンテナ1-mによりそれぞれ受信されたM個の信号を検波し、検波したM個の信号のそれぞれをアナログ信号からデジタル信号に変換する。
信号処理装置2のヌルずれ推定部11及びビーム形成部13には、変換されたM個のデジタル信号であるデジタル受信信号を含んでいる受信信号ベクトルが与えられる。 Next, the operation will be described.
First, the
The
The null
式(1)において、tは時刻、aJ(u0 (k))は、第k番目の妨害波の到来方向u0 (k)=[u0 (k),v0 (k)]Tに対するステアリングベクトルである。Tは転置を示す記号である。
jk(t)は、第k番目の妨害波の複素振幅、n0(t)は、受信機雑音ベクトルである。 During the listening period, a received signal vector x 0 (t) shown in the following equation (1) is given to the null
In Expression (1), t is time, and a J (u 0 (k) ) is the arrival direction u 0 (k) = [u 0 (k) , v 0 (k) ] T Is a steering vector. T is a symbol indicating transposition.
j k (t) is the complex amplitude of the k-th jamming wave, and n 0 (t) is the receiver noise vector.
式(2)において、E[・]は、・に関するアンサンブル平均を示す記号である。Hは、エルミート転置を示す記号である。
式(2)では、リスニング期間における異なる時刻tの有限個数の受信信号ベクトルx0(t)を用いている。
第1の相関行列算出部41は、算出した妨害波の相関行列R0をベクトル算出部42及び補償ウェイト算出部12の補償型相関行列算出部53に出力する。 When the first correlation
In Equation (2), E [•] is a symbol indicating an ensemble average with respect to •. H is a symbol indicating Hermitian transposition.
In Expression (2), a finite number of received signal vectors x 0 (t) at different times t in the listening period are used.
The first
メインビーム方向usは、リスニング期間が終了した後のビーム送信期間中に、アレーアンテナ1から送信されるビームにおけるメインビームの方向である。
また、ベクトル算出部42は、リスニング期間が終了した後のビーム送信期間中に、アレーアンテナ1から送信されるビームのメインビーム方向usを走査するためのウェイト拘束ベクトルa(us)を取得する。
The main beam direction u s is in the beam transmission period after the listening period ends, the direction of the main beam in the beam transmitted from the
Furthermore, the
式(3)において、αは、事前に設定された規格化係数である。
ベクトル算出部42は、算出したウェイトベクトルw(u)を評価関数算出部44に出力する。
なお、ベクトル算出部42により算出されるウェイトベクトルw(u)は、妨害波の到来方向u0 (k)にヌルを形成するためのベクトルであり、メインビーム方向usにおけるウェイトベクトルw(us)=αR0 -1a(us)を妨害波のスキャン方向uに走査するウェイトベクトルに相当する。 The
In Expression (3), α is a normalization coefficient set in advance.
The
Incidentally, the weight vector w to be calculated by the vector calculating unit 42 (u) is a vector to form a null in the arrival direction u 0 of the disturbance (k), the weight vector w (u in the main beam direction u s s ) = αR 0 −1 a (u s ) corresponds to a weight vector for scanning in the scanning direction u of the interference wave.
式(4)において、s(t)は目標信号、asは、目標信号s(t)の到来方向に対するステアリングベクトル、n(t)は、受信機雑音ベクトルであり、受信機雑音ベクトルn(t)の特性は、リスニング期間における受信機雑音ベクトルn0(t)の特性と同じである。
u0 (k)+δukは、ビーム送信期間における第k番目の妨害波の到来方向であり、リスニング期間における第k番目の妨害波の到来方向とずれている。
δuk=[δuk,δvk]Tは、ビーム送信期間における第k番目の妨害波の到来方向と、リスニング期間における第k番目の妨害波の到来方向とのずれである。 During the beam transmission period after the end of the listening period, a received signal vector x (t) shown in the following equation (4) is given to the null
In the formula (4), s (t) is the target signal, a s is the steering vector for the direction of arrival of the target signal s (t), n (t ) is the receiver noise vector, receiver noise vector n ( The characteristics of t) are the same as the characteristics of the receiver noise vector n 0 (t) during the listening period.
u 0 (k) + δu k is the arrival direction of the k-th jamming wave in the beam transmission period, and is shifted from the arrival direction of the k-th jamming wave in the listening period.
δu k = [δu k , δv k ] T is the difference between the arrival direction of the kth jamming wave in the beam transmission period and the arrival direction of the kth jamming wave in the listening period.
第2の相関行列算出部43は、算出した受信信号の相関行列Rxを評価関数算出部44に出力する。 The second correlation
The second correlation
式(6)の分母であるwH(u)Rxw(u)は、ウェイトベクトルw(u)によるビームの走査出力電力である。
ウェイトベクトルw(u)は、上述したように、メインビーム方向usにおけるウェイトベクトルw(us)を妨害波のスキャン方向uに走査するためのウェイトベクトルであるため、ウェイトベクトルw(u)により形成される妨害波の到来方向uに対するヌルもスキャンされる。 The evaluation
W H (u) R x w (u), which is the denominator of Equation (6), is the scanning output power of the beam by the weight vector w (u).
As described above, the weight vector w (u) is a weight vector for scanning the weight vector w (u s ) in the main beam direction u s in the interference wave scanning direction u, and thus the weight vector w (u). The null for the direction of arrival u of the jamming wave formed by is also scanned.
このヌルを形成する方向u0 (k)+δukは、受信信号の相関行列Rxに含まれている第k番目の妨害波の到来方向u0 (k)+δukと一致するので、wH(us+δuk)Rxw(us+δuk)に含まれている第k番目の妨害波の電力が最小化される。
したがって、評価関数算出部44により算出される評価関数P(u)は、スキャン方向u=us+δukにおいて、関数値がピークを示し、ピークの関数値に対応するuであるδukがヌルずれの候補となる。
ヌルずれの候補は、合計K個存在しているので、K個の候補の中で、関数値が最大の候補がヌルずれの推定値δuハットとなる。明細書の文章中では、電子出願の都合上、文字の上に“^”の記号を付することができないので、「δuハット」のように表記している。
評価関数算出部44は、算出した評価関数P(u)をヌルずれ推定処理部45に出力する。 Therefore, the weight vector w (u), the scanning direction u is if u s + .delta.u k, to form a null in the direction of u 0 (k) + δu k .
This null the formation direction u 0 (k) + δu k coincides with the arrival direction u 0 (k) + δu k of the k-th interference wave contained in the correlation matrix R x of the received signal, w H (u s + δu k) R x w (u s + δu k) of the k-th included in the interference wave power is minimized.
Therefore, the evaluation
Since there are a total of K null-candidate candidates, the candidate having the maximum function value among the K candidates is the null-shift estimated value δu hat. In the text of the specification, for the convenience of electronic application, the symbol “^” cannot be added on the letter, so it is represented as “δu hat”.
The evaluation
ヌルずれの推定値δuハットを算出する際、wH(us+δuk)Rxw(us+δuk)に含まれている目標信号の電力は、不要電力であるから、事前に目標信号の電力を低減することができれば、評価関数P(u)を用いるヌルずれの推定精度が向上する。
そのため、ベクトル算出部42は、式(3)の代わりに、以下の式(7)によって、妨害波のスキャン方向uを走査するためのウェイトベクトルw(u)を算出するようにしてもよい。
式(7)において、DΔは、差ビーム形成用のテーパを対角項に有する対角行列である。
w(u)は、妨害波の到来方向u及びメインビーム方向usにヌルを形成するウェイトベクトルである。
メインビーム方向usにヌルを形成するため、メインビーム方向usの近傍から到来する目標信号は抑圧され、wH(us+δuk)Rxw(us+δuk)に含まれている目標信号の電力が低減される。 Here, the power of the k-th interference wave is minimized, the power of the interference wave other than the power and the k-th target signal included in the correlation matrix R x of the received signal is still remaining .
When calculating the estimated value .delta.u hat null shift, power w H (u s + δu k ) R x w (u s + δu k) to Including target signal, because it is unnecessary power, advance the target signal Can be reduced, the estimation accuracy of the null shift using the evaluation function P (u) can be improved.
Therefore, the
In Equation (7), DΔ is a diagonal matrix having a difference beam forming taper in the diagonal terms.
w (u) is a weight vector forming a null in an arrival direction u and the main beam direction u s jammer.
To form a null in the main beam direction u s, target signal coming from the vicinity of the main beam direction u s is suppressed, it is included in w H (u s + δu k ) R x w (u s + δu k) The power of the target signal is reduced.
この場合、評価関数P(u)は、スキャン方向u=us+δuにおいて、関数値がピークを示すので、ピークの関数値に対応するuであるδuがヌルずれの候補となり、ピークの関数値に対応するuであるδuがヌルずれの推定値δuハットとなる。 In the description so far, δu k = [δu k , δv k ] T is defined as the difference between the arrival direction of the k-th jamming wave in the listening period and the arrival direction of the k-th jamming wave in the beam transmission period. However, if the difference in deviation due to the K interference waves is so small that it can be ignored, the deviation may be treated as δu = [δu, δv] T.
In this case, since the function value indicates a peak in the scan direction u = u s + δu in the scan direction u = u s + δu, u corresponding to the peak function value is a candidate for null shift, and the peak function value Δu corresponding to u is the null deviation estimated value δu hat.
式(8)において、i,jは行列要素番号であり、i=1,2,・・・,M、j=1,2,・・・,Mである。
式(8)では、第m番目のサブアレーアンテナ1-mの座標をPm=[xk,yk]Tとし、Δxij及びΔyijは、それぞれ相対座標である。
Δxij=xi-xjであり、Δyij=yi-yjである。λは送信波長である。
式(8)では、CMT行列TCMTによる設定ヌル幅をΔu=[Δu,Δv]Tとしている。
CMT行列TCMTによる設定ヌル幅Δuは、ヌルずれの推定値δuハットに基づいて、以下の式(9)のように決定される。
式(9)において、ku,kvは、任意の係数であり、ヌルずれの推定値δuハットと関係なく、ビーム形成で用いるテーパに応じて事前に設定される値である。
CMT行列算出部51は、算出したCMT行列TCMTを補償型相関行列算出部53に出力する。 When the CMT
In equation (8), i and j are matrix element numbers, i = 1, 2,..., M, j = 1, 2,.
In Equation (8), the coordinates of the m-th subarray antenna 1-m are P m = [x k , y k ] T, and Δx ij and Δy ij are relative coordinates.
Δx ij = x i −x j and Δy ij = y i −y j . λ is a transmission wavelength.
In the equation (8), the set null width by the CMT matrix T CMT is Δu = [Δu, Δv] T.
The set null width Δu based on the CMT matrix T CMT is determined as shown in the following formula (9) based on the null deviation estimated value δu hat.
In Equation (9), k u and k v are arbitrary coefficients, and are values set in advance according to the taper used in beam forming, regardless of the estimated null shift estimated value δu hat.
The CMT
式(10)において、二重丸の記号は、CMT行列TCMTと妨害波の相関行列R0との行列要素同士の乗算を行うアダマール積を示す記号である。
補償型相関行列算出部53は、算出したヌルずれ補償型相関行列Rを補償型ウェイト算出部54に出力する。 The compensation-type correlation
In Expression (10), a double circle symbol is a symbol indicating a Hadamard product that performs multiplication of matrix elements of the CMT matrix T CMT and the correlation matrix R 0 of the interference wave.
The compensation type correlation
補償型ウェイト算出部54は、以下の式(11)に示すように、ウェイト拘束ベクトルa(us)と補償型相関行列算出部53から出力されたヌルずれ補償型相関行列Rとを用いて、ヌルずれを補償する補償ウェイトを示す補償ウェイトベクトルwAを算出する(図6のステップST8)。
式(11)において、βは規格化係数である。
補償型ウェイト算出部54は、算出した補償ウェイトベクトルwAをビーム形成部13に出力する。
The compensation
In Expression (11), β is a normalization coefficient.
The compensation
When the reception signal vector x (t) during the beam transmission period after the end of the listening period is given, the
ビーム形成部13の加算器15は、M個の乗算器14-mからそれぞれ出力されたM個のデジタル受信信号を合成し、合成後のデジタル受信信号を受信ビームy(t)として出力する。
受信信号ベクトルx(t)に補償ウェイトベクトルwAが乗算されているので、受信ビームy(t)には、妨害波の到来方向u0を中心として、設定ヌル幅がΔuのヌルが形成されている。 That is, the M multipliers 14-m in the
The
Since the reception signal vector x (t) is multiplied by the compensation weight vector w A , a null having a set null width Δu is formed in the reception beam y (t) with the arrival direction u 0 of the disturbing wave as the center. ing.
上記実施の形態1では、補償ウェイト算出部12が、CMT行列算出部51を備え、CMT行列算出部51により算出されたCMT行列TCMTを用いて、ヌルずれを補償する補償ウェイトを示す補償ウェイトベクトルwAを算出する例を示している。
この実施の形態2では、補償ウェイト算出部12が、CMT行列TCMTを用いずに、ヌルずれを補償する補償ウェイトを示す補償ウェイトベクトルwAを算出する例を説明する。
In the first embodiment, the compensation
In the second embodiment, an example will be described in which the compensation
ウェイト算出処理部55は、補償型相関行列算出部56及び補償型ウェイト算出部54を備えている。
補償型相関行列算出部56は、ヌルずれ推定部11のヌルずれ推定処理部45により推定されたヌルずれと、ヌルずれ推定部11の第1の相関行列算出部41により算出された妨害波の相関行列とから、ヌルずれ補償型相関行列を算出する処理を実施する。 FIG. 7 is a block diagram showing a compensation
The weight
The compensation-type correlation
上記実施の形態1では、リスニング期間における第k番目の妨害波の到来方向と、ビーム送信期間における第k番目の妨害波の到来方向とのずれをδuk=[δuk,δvk]Tとしている。
この実施の形態2では、K個の妨害波のずれの違いが無視できる程に小さい場合を想定し、ずれをδu=[δu,δv]Tとして扱う例を説明する。 Next, the operation will be described.
In the first embodiment, the difference between the arrival direction of the k-th jamming wave in the listening period and the arrival direction of the k-th jamming wave in the beam transmission period is set as δu k = [δu k , δv k ] T. Yes.
In the second embodiment, an example will be described in which the difference between K interference waves is assumed to be negligibly small, and the difference is handled as δu = [δu, δv] T.
式(13)において、u0 (k)+δuは、ビーム送信期間における第k番目の妨害波の到来方向であり、リスニング期間における第k番目の妨害波の到来方向とずれている。 Therefore, in the second embodiment, during the beam transmission period after the listening period ends, the received signal vector x (t) shown in the following equation (13) is converted to the null
In Expression (13), u 0 (k) + δu is the arrival direction of the kth jamming wave in the beam transmission period, and is shifted from the arrival direction of the kth jamming wave in the listening period.
第2の相関行列算出部43は、算出した受信信号の相関行列Rxを評価関数算出部44に出力する。 The second correlation
The second correlation
式(6)の分母であるwH(u)Rxw(u)は、ウェイトベクトルw(u)によるビームの走査出力電力である。
ウェイトベクトルw(u)は、上述したように、メインビーム方向usにおけるウェイトベクトルw(us)を妨害波のスキャン方向uに走査するためのウェイトベクトルであるため、ウェイトベクトルw(u)により形成される妨害波の到来方向uに対するヌルもスキャンされる。 The evaluation
W H (u) R x w (u), which is the denominator of Equation (6), is the scanning output power of the beam by the weight vector w (u).
As described above, the weight vector w (u) is a weight vector for scanning the weight vector w (u s ) in the main beam direction u s in the interference wave scanning direction u, and thus the weight vector w (u). The null for the direction of arrival u of the jamming wave formed by is also scanned.
このヌルを形成する方向u0 (k)+δuは、受信信号の相関行列Rxに含まれている第k番目の妨害波の到来方向u0 (k)+δuと一致するので、wH(us+δu)Rxw(us+δu)に含まれている第k番目の妨害波の電力が最小化される。
したがって、評価関数算出部44により算出される評価関数P(u)は、スキャン方向u=us+δuにおいて、関数値がピークを示し、ピークの関数値に対応するuであるδuがヌルずれの推定値δuハットとなる。
評価関数算出部44は、算出した評価関数P(u)をヌルずれ推定処理部45に出力する。 Therefore, the weight vector w (u) forms a null in the direction of u 0 (k) + δu if the scan direction u is u s + δu.
Since the direction u 0 (k) + δu forming this null coincides with the arrival direction u 0 (k) + δu of the k-th jamming wave included in the correlation matrix R x of the received signal, w H (u s + .delta.u) power R x w (u s + δu k-th interference wave contained in) is minimized.
Therefore, the evaluation function P (u) calculated by the evaluation
The evaluation
補償型相関行列算出部56は、算出したヌルずれ補償型相関行列R0’を補償型ウェイト算出部54に出力する。 The compensation-type correlation
The compensation type correlation
式(14)において、A0は、K個のステアリングベクトルaJ(u0 (k))を並べた行列、Jはjk(t)の相関行列、σ2は受信機雑音電力である。
一方、ビーム送信期間中の妨害波の相関行列R0’は、以下の式(15)のように表すことができる。ビーム送信期間中の妨害波の相関行列R0’は、ヌルずれ補償型相関行列に相当する。
式(15)において、A0’は、K個のステアリングベクトルaJ(u0 (k)+δu)を並べた行列である。 Here, the interference matrix correlation matrix R 0 calculated by the first
In Expression (14), A 0 is a matrix in which K steering vectors a J (u 0 (k) ) are arranged, J is a correlation matrix of j k (t), and σ 2 is receiver noise power.
On the other hand, the interference matrix R 0 ′ of the interference wave during the beam transmission period can be expressed as the following equation (15). The interference matrix correlation matrix R 0 ′ during the beam transmission period corresponds to a null shift compensation correlation matrix.
In Expression (15), A 0 ′ is a matrix in which K steering vectors a J (u 0 (k) + δu) are arranged.
よって、式(15)は、以下の式(17)のように表すことができる。
式(17)の関係より、ヌルずれの推定値δuハットと、妨害波の相関行列R0とから、ヌルずれ補償型相関行列として、以下の式(18)のようにR0’を算出することができる。
At this time, if a diagonal matrix having a path difference phase component due to the deviation δu in the diagonal term is D (δu), the following equation (16) is established.
Therefore, Expression (15) can be expressed as the following Expression (17).
From the relationship of the equation (17), R 0 ′ is calculated as a null displacement compensation type correlation matrix from the null displacement estimation value δu hat and the interference matrix correlation matrix R 0 as in the following equation (18). be able to.
補償型ウェイト算出部54は、以下の式(19)に示すように、ウェイト拘束ベクトルa(us)と補償型相関行列算出部53から出力されたヌルずれ補償型相関行列R0’とを用いて、ヌルずれを補償する補償ウェイトを示す補償ウェイトベクトルwAを算出する。
補償型ウェイト算出部54は、算出した補償ウェイトベクトルwAをビーム形成部13に出力する。
The compensation
The compensation
受信信号ベクトルx(t)に補償ウェイトベクトルwAが乗算されているので、受信ビームy(t)には、妨害波の到来方向u0を中心として、設定ヌル幅がΔuのヌルが形成されている。 When the reception signal vector x (t) during the beam transmission period after the end of the listening period is given, the
Since the reception signal vector x (t) is multiplied by the compensation weight vector w A , a null having a set null width Δu is formed in the reception beam y (t) with the arrival direction u 0 of the disturbing wave as the center. ing.
Claims (5)
- 1つ以上の素子アンテナを含んでいるサブアレーアンテナが複数並べられているアレーアンテナと、
前記アレーアンテナからビームが送信されない期間であるリスニング期間中に、前記複数のサブアレーアンテナによりそれぞれ受信された複数の信号と、前記リスニング期間が終了した後の前記ビームが送信される期間であるビーム送信期間中に、前記複数のサブアレーアンテナによりそれぞれ受信された複数の信号とから、前記リスニング期間における妨害波の到来方向と前記ビーム送信期間における妨害波の到来方向との変化であるヌルずれを推定するヌルずれ推定部と、
前記ヌルずれ推定部により推定されたヌルずれに基づいて、前記ビーム送信期間中に、前記複数のサブアレーアンテナによりそれぞれ受信された複数の信号に対する重み係数として、前記ヌルずれを補償する補償ウェイトを算出する補償ウェイト算出部と、
前記ビーム送信期間中に、前記複数のサブアレーアンテナによりそれぞれ受信された複数の信号に前記補償ウェイト算出部により算出された補償ウェイトを乗算し、補償ウェイト乗算後の複数の信号を合成するビーム形成部と
を備えたアダプティブアレーアンテナ装置。 An array antenna in which a plurality of subarray antennas including one or more element antennas are arranged;
During a listening period in which no beam is transmitted from the array antenna, a plurality of signals respectively received by the plurality of subarray antennas and a beam transmission in which the beam after the listening period is transmitted are transmitted. During the period, a null shift that is a change between the arrival direction of the interference wave in the listening period and the arrival direction of the interference wave in the beam transmission period is estimated from the plurality of signals respectively received by the plurality of subarray antennas. A null shift estimation unit;
Based on the null shift estimated by the null shift estimation unit, a compensation weight that compensates for the null shift is calculated as a weighting factor for a plurality of signals respectively received by the plurality of subarray antennas during the beam transmission period. A compensation weight calculation unit for
A beam forming unit that multiplies a plurality of signals respectively received by the plurality of sub-array antennas during the beam transmission period by a compensation weight calculated by the compensation weight calculation unit, and combines the plurality of signals after the compensation weight multiplication. And an adaptive array antenna device. - 前記ヌルずれ推定部は、
前記リスニング期間中に、前記複数のサブアレーアンテナによりそれぞれ受信された複数の信号から、前記妨害波の相関行列を算出する第1の相関行列算出部と、
前記ビームのメインビーム方向を走査するためのウェイト拘束ベクトルと、前記第1の相関行列算出部により算出された妨害波の相関行列とを用いて、前記妨害波のスキャン方向を走査するためのウェイトベクトルを算出するベクトル算出部と、
前記ビーム送信期間中に、前記複数のサブアレーアンテナによりそれぞれ受信された複数の信号から、前記アレーアンテナの受信信号の相関行列を算出する第2の相関行列算出部と、
前記ベクトル算出部により算出されたウェイトベクトルと、前記第2の相関行列算出部により算出された受信信号の相関行列とを用いて、前記ヌルの推定に用いる評価関数を算出する評価関数算出部と、
前記評価関数算出部により算出された評価関数を用いて、前記ヌルずれを推定するヌルずれ推定処理部とを備えていることを特徴とする請求項1記載のアダプティブアレーアンテナ装置。 The null shift estimator is
A first correlation matrix calculation unit for calculating a correlation matrix of the jamming wave from a plurality of signals respectively received by the plurality of subarray antennas during the listening period;
The weight for scanning the scanning direction of the interference wave using the weight constraint vector for scanning the main beam direction of the beam and the correlation matrix of the interference wave calculated by the first correlation matrix calculation unit. A vector calculation unit for calculating a vector;
A second correlation matrix calculation unit for calculating a correlation matrix of a received signal of the array antenna from a plurality of signals respectively received by the plurality of sub-array antennas during the beam transmission period;
An evaluation function calculation unit that calculates an evaluation function used for estimation of the null using the weight vector calculated by the vector calculation unit and the correlation matrix of the received signal calculated by the second correlation matrix calculation unit; ,
The adaptive array antenna apparatus according to claim 1, further comprising: a null shift estimation processing unit that estimates the null shift using the evaluation function calculated by the evaluation function calculation unit. - 前記ベクトル算出部は、前記メインビーム方向と前記スキャン方向の差による行路差位相成分を対角項に有する対角行列と、前記ウェイト拘束ベクトルと、前記第1の相関行列算出部により算出された妨害波の相関行列とを乗算することで、前記ウェイトベクトルを算出することを特徴とする請求項2記載のアダプティブアレーアンテナ装置。 The vector calculation unit is calculated by a diagonal matrix having a path difference phase component due to a difference between the main beam direction and the scan direction in a diagonal term, the weight constraint vector, and the first correlation matrix calculation unit. The adaptive array antenna apparatus according to claim 2, wherein the weight vector is calculated by multiplying a correlation matrix of an interference wave.
- 前記補償ウェイト算出部は、
前記ヌルずれ推定処理部により推定されたヌルずれから、ヌル幅を設定する行列であるCMT行列を算出するCMT行列算出部と、
前記CMT行列算出部により算出されたCMT行列と前記第1の相関行列算出部により算出された妨害波の相関行列とから、前記ヌルずれを補償する補償ウェイトを算出するウェイト算出処理部とを備えていることを特徴とする請求項2記載のアダプティブアレーアンテナ装置。 The compensation weight calculation unit
A CMT matrix calculating unit that calculates a CMT matrix that is a matrix for setting a null width from the null shift estimated by the null shift estimation processing unit;
A weight calculation processing unit that calculates a compensation weight for compensating for the null shift from the CMT matrix calculated by the CMT matrix calculation unit and the interference matrix of the interference wave calculated by the first correlation matrix calculation unit; The adaptive array antenna apparatus according to claim 2, wherein: - 前記補償ウェイト算出部は、
前記ヌルずれ推定処理部により推定されたヌルずれと前記第1の相関行列算出部により算出された妨害波の相関行列とから、前記ヌルずれを補償する補償ウェイトを算出するウェイト算出処理部を備えていることを特徴とする請求項2記載のアダプティブアレーアンテナ装置。 The compensation weight calculation unit
A weight calculation processing unit that calculates a compensation weight that compensates for the null shift from the null shift estimated by the null shift estimation processing unit and the correlation matrix of the interference wave calculated by the first correlation matrix calculation unit; The adaptive array antenna apparatus according to claim 2, wherein:
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2020148802A1 (en) * | 2019-01-15 | 2020-07-23 | 三菱電機株式会社 | Beam formation device, radar device, and beam formation method |
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GB201910715D0 (en) | 2019-09-11 |
GB2573909A (en) | 2019-11-20 |
JPWO2018167952A1 (en) | 2019-06-27 |
JP6573745B2 (en) | 2019-09-11 |
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