JP2009098070A - Radar equipment - Google Patents

Abstract

A radar apparatus capable of measuring angles with high accuracy in a multipath environment without changing the frequency of a signal to be transmitted and received.
An aperture division signal generator 41 for generating an aperture division signal from a Σ beam and a Δ beam generated based on a received signal, and an arbitrary directivity direction based on the aperture division signal generated by the aperture division signal generator A plurality of phase monopulse beams each having a phase monopulse beam reformer for reshaping a phase monopulse beam composed of a Σ beam and a Δ beam, and a phase monopulse beam reformer. A reshaped beam extractor 43 that extracts a Σ beam and a Δ beam in a directional direction that maximizes the output of the Σ beam from a plurality of phase monopulse beams, and the Σ beam and the Δ beam extracted by the reshaped beam extractor And an angle measurement processor 45 for calculating an angle value by phase monopulse angle measurement.
[Selection] Figure 1

Description

  The present invention relates to a radar device that detects a target, and more particularly to a technique for measuring a target angle in a multipath environment.

  The radar device (or receiving device) receives a multipath wave in addition to the direct wave from the target in a multipath environment. Therefore, the direct wave and the multipath wave are vector-synthesized to reduce the level of the received signal, and the accuracy of monopulse angle measurement may be extremely reduced.

  In order to deal with such problems, observation is performed by changing the phase relationship between the direct wave and multipath wave by using signals of multiple frequencies, and the level of the reference beam (Σ beam) in the observed signal There is known a “frequency hopping method” in which angle measurement is performed using a signal having the highest frequency (see Non-Patent Document 1, for example).

FIG. 19 is a block diagram showing the configuration of such a conventional radar apparatus. This radar apparatus includes an exciter 1 a, an antenna 2, a first receiver 3 ₁ , a second receiver 3 _2, and a signal processor 4.

  The exciter 1a converts the frequency of a pulse signal generated by a signal generator (not shown) into a frequency for transmission while sequentially changing the frequency, and sends the frequency to the antenna 2. The antenna 2 includes a plurality of antenna elements 21, a plurality (the same number as the antenna elements 21) of transmission / reception modules 22 and a power feeding circuit 23. Since each of the plurality of antenna elements 21 has the same configuration, one antenna element will be referred to as “antenna element 21” in the following description. Similarly, since the configuration of each of the plurality of transmission / reception modules 22 is the same, one transmission / reception module will be hereinafter referred to as “transmission / reception module 22”.

  The antenna element 21 transmits a high-frequency signal transmitted from the transmission / reception module 22 toward the air, and receives a signal from the air, that is, a direct wave and a multipath wave reflected from the target, and transmits the signals to the transmission / reception module 22. .

  As shown in FIG. 20, the transmission / reception module 22 includes a circulator 221, a transmission side amplifier 222a, a transmission side phase shifter 223a, a reception side amplifier 222b, and a reception side phase shifter 223b. The circulator 221 switches between sending a high-frequency transmission signal sent from the transmission-side amplifier 222a to the antenna element 21 or sending a high-frequency reception signal sent from the antenna element 21 to the reception-side amplifier 222b.

  The transmission-side amplifier 222 a amplifies the high-frequency transmission signal sent from the transmission-side phase shifter 223 a and sends it to the antenna element 21 via the circulator 221. The transmission-side phase shifter 223a adjusts the phase of the transmission signal sent from the power feeding circuit 23, converts it to a high-frequency transmission signal, and sends it to the transmission-side amplifier 222a.

  The reception side amplifier 222b amplifies the high frequency reception signal sent from the antenna element 21 via the circulator 221, and sends it to the reception side phase shifter 223b. The reception-side phase shifter 223b adjusts the phase of the high-frequency reception signal sent from the reception-side amplifier 222b, converts it to an intermediate frequency signal, and sends it to the power feeding circuit 23 as a reception signal.

The power feeding circuit 23 includes a transmission synthesizer and a reception synthesizer including a monopulse comparator (both are not shown). The transmission distributor distributes the power of the pulse signal sent from the exciter 1 a and sends it to the plurality of transmission / reception modules 22. The reception synthesizer synthesizes reception signals sent from the plurality of transmission / reception modules 22 to generate a Σ beam signal (hereinafter simply referred to as “Σ beam”) and a Δ beam signal (hereinafter simply referred to as “Δ beam”). Call). The Δ beam is composed of a ΔAZ beam and a ΔEL beam. The Σ beam generated by the feeding circuit 23 is sent to the first receiver 3 ₁ as a reference beam, and the Δ beam is sent to the second receiver 3 ₂ .

The first receiver 3 ₁ converts the frequency of the Σ beam sent from the power feeding circuit 23, further converts it into a digital signal, and sends it to the signal processor 4. The second receiver 3 ₂ converts the frequency of the Δ beam sent from the power feeding circuit 23, further converts it into a digital signal, and sends it to the signal processor 4.

The signal processor 4 includes a detector 46 and a goniometer 47. Detector 46 detects a target by comparing the incoming Σ beam transmitted from the first receiver 3 ₁ with a predetermined threshold level, the Σ beam at that time, and sends the goniometer 47. Goniometer 47 calculates the Σ beam sent from the detector 46, the angle measurement value representative of the angle of the target direction based on the Δ beam sent from the second receiver 3 _2, as the target information Output to the outside.

  The operation of the conventional radar apparatus configured as described above will be described. The signal sent out from the exciter 1 a is distributed by the transmission distributor of the power feeding circuit 23 in the antenna 2 and sent to the transmission / reception module 22. The phase is controlled by the transmission side phase shifter 223 a of the transmission / reception module 22, amplified by the transmission side amplifier 222 a, and radiated from the antenna element 21 to the space via the circulator 221.

A signal input from the antenna element 21 is sent to the reception side amplifier 222b via the circulator 221 of the transmission / reception module 22 and amplified. The signal amplified by the reception side amplifier 222 b is phase-controlled by the reception side phase shifter 223 b and then sent to the power feeding circuit 23. Then, the Σ beam and the Δ beam are generated by the reception synthesizer of the power feeding circuit 23 and sent to the first receiver 3 ₁ and the second receiver 3 ₂ , respectively.

The first receiver 3 ₁ converts the frequency of the Σ beam sent from the power feeding circuit 23, and the second receiver 3 ₂ converts the frequency of the Δ beam sent from the power feeding circuit 23, and further converts it into a digital signal. To the signal processor 4. As described above, the signal processor 4 detects the target based on the Σ beam, and further performs angle measurement based on the Σ beam and the Δ beam.

In this conventional radar apparatus, the exciter 1a sequentially generates transmission signals of a plurality of frequencies and sends them to the antenna 2. The first receiver 3 ₁ changes the local signal, generates a Σ beam corresponding to each frequency, and sends it to the signal processor 4. Similarly, the first receiver 3 ₂ by changing the local signal and sends the signal processor 4 to generate a Δ beam corresponding to each frequency. In the signal processor 4, the detection of the target is performed using the highest frequency of the Σ beam level in the Σ beam obtained from the first receiver 3 _1, further angular process measurement using the Δ beam at that time Is done. Thereby, observation is performed by a frequency hopping method in which the phase relationship between the direct wave and the multipath wave is changed.
(Angle measurement under multipath environment) E.BOSSE, “Model-Based Multifrequency Array Signal Processing for Low-Angle Tracking”, IEEE Trans. AES. Vol.31, No.1, pp.194-210, Jan. 1995)

  In the above-described conventional radar apparatus, since it is necessary to use a plurality of separated frequencies as the frequency of the transmission / reception signal, the processing scale or the apparatus scale increases, and the observation time is required to transmit / receive the signals of the plurality of frequencies. There is a problem of becoming longer. In addition, when the sub-pulse method in which the transmission pulse is divided by the frequency is used, there is a problem that the system gain is lowered.

  In addition, not only in a multipath environment, but when performing monopulse angle measurement, if the target deviates greatly from the pointing direction, there is a problem that error voltage error increases and angle measurement accuracy deteriorates.

  An object of the present invention is to provide a radar apparatus that can measure angles with high accuracy in a multipath environment without changing the frequency of a signal to be transmitted and received.

  In order to solve the above-described problems, a first invention is an aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam that are generated based on a received signal, and an aperture that is generated by the aperture division signal generator. A plurality of phase monopulse beams having arbitrary directivity directions based on the divided signals, each of which is a phase monopulse beam reformer for reshaping a phase monopulse beam composed of a Σ beam and a Δ beam; A reshaped beam extractor that extracts a Σ beam and a Δ beam in a directivity direction in which the output of the Σ beam is maximum from among a plurality of phase monopulse beams reshaped by the detector, and a Σ extracted by the reshaped beam extractor And an angle measuring processor that calculates an angle measurement value by phase monopulse angle measurement using the beam and the Δ beam.

  Further, the second invention is based on the aperture division signal generator that generates the aperture division signal from the Σ beam and the Δ beam that are generated based on the received signal, and the aperture division signal that is generated by the aperture division signal generator. A plurality of phase monopulse beams having the directivity directions of the squint beam, each of which is reshaped by a squint beam reformer for reshaping a squint beam composed of a ΣL beam and a ΣU beam. A reshaped beam extractor for extracting a ΣL beam and a ΣU beam in a directional direction in which the output of the ΣL beam is maximum from a plurality of squint beams, and a ΣL beam and a ΣL beam extracted by the reshaped beam extractor And an angle measuring processor for calculating an angle value by squint angle measurement.

  The third aspect of the invention relates to an aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam that are generated based on a received signal, and an aperture division signal that is generated by the aperture division signal generator. A plurality of phase monopulse beams having a directivity direction, each of which is reformed by a phase monopulse beam reformer for reshaping a phase monopulse beam composed of a Σ beam and a Δ beam, and a phase monopulse beam reformer A reshaped beam extractor that extracts a Σ beam and a Δ beam from which the absolute value of the imaginary component of the error voltage is minimized among a plurality of phase monopulse beams, and the Σ beam and the Δ beam extracted by the reshaped beam extractor And an angle measurement processor for calculating an angle value by phase monopulse angle measurement.

  According to a fourth aspect of the present invention, there is provided an aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam that are generated based on a received signal, and an aperture division signal that is generated by the aperture division signal generator. A plurality of phase monopulse beams having the directivity directions of the squint beam, each of which is reshaped by a squint beam reformer for reshaping a squint beam composed of a ΣL beam and a ΣU beam. A reshaped beam extractor for extracting a ΣL beam and a ΣU beam that minimize the absolute value of the imaginary component of the error voltage from a plurality of squint beams, and a ΣL beam and a ΣL beam extracted by the reshaped beam extractor And an angle measurement processor for calculating an angle measurement value by squint angle measurement.

  In addition, the fifth aspect of the invention is a goniometer that performs angle measurement based on the Σ beam and Δ beam generated based on the received signal, and generates an aperture division signal from the Σ beam and Δ beam generated based on the received signal. An aperture division signal generator, and a phase monopulse beam composed of a Σ beam and a Δ beam having a predetermined directivity direction based on the aperture division signal generated by the aperture division signal generator are re-formed. A phase monopulse beam reformer that redirects the phase monopulse beam according to the angle measurement value, and a phase monopulse angle measurement value using a Σ beam and a Δ beam redirected by the phase monopulse beam reformer. And an angle measuring processor for calculating.

  According to a sixth aspect of the present invention, a goniometer that performs angle measurement based on a Σ beam and a Δ beam generated based on a received signal, and generates an aperture division signal from the Σ beam and the Δ beam generated based on the received signal. Angle measurement values measured by the angle finder from the angle measurement values having an ambiguity calculated based on the phase difference between the aperture division signal generator and the aperture division signal generated by the aperture division signal generator. And a phase angle measuring device for selecting angle measurement values included in a predetermined range before and after the target angle indicated by.

  According to the first invention, when a direct wave and a multipath wave are received by a phase monopulse beam, a plurality of phase monopulse beams having different directivity directions are reformed, and the output of the Σ beam therein is maximized. Since angle measurement is performed using the Σ beam and Δ beam in the pointing direction, the influence of multipath waves can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  According to the second invention, when a direct wave and a multipath wave are received by a squint beam, a plurality of squint beams having different directivity directions are re-formed, and the output of the ΣL beam among them is maximized. Since the angle measurement is performed using the ΣL beam and ΣU beam in the directivity direction, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  According to the third invention, when a direct wave and a multipath wave are received by a phase monopulse beam, a plurality of phase monopulse beams having different directing directions are re-formed, and the absolute value of the imaginary part therein is Since the angle is measured using the minimum Σ beam and Δ beam, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  According to the fourth invention, when a direct wave and a multipath wave are received by a squint beam, a plurality of squint beams having different directivity directions are re-formed, and an absolute value of an imaginary part therein is Since the angle is measured using the minimum ΣL beam and ΣU beam, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  According to the fifth aspect of the invention, even when the pointing direction of the phase monopulse beam is deviated from the target, the Σ beam and Δ beam that direct the pointing direction toward the target direction are re-formed and re-formed. Since the angle is measured using the Σ beam and Δ beam, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  According to the sixth aspect of the present invention, the angle by the Σ beam and the Δ beam is selected from the highly accurate angle measurement values having the angle ambiguity calculated by the phase difference between the aperture division signals formed from the Σ beam and the Δ beam. Since the angle measurement value included in the predetermined range before and after the target angle indicated by the angle measurement value having no ambiguity is selected, a highly accurate angle measurement value having no angle ambiguity can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, parts corresponding to the constituent parts of the conventional radar apparatus described in the background art section are denoted by the same reference numerals as those used in the background art section, and description thereof is omitted or simplified.

  The radar apparatus according to Embodiment 1 of the present invention employs a phase monopulse angle measurement method as the angle measurement method. Phase monopulse angle measurement is described in “The Institute of Electronics, Information and Communication Engineers, Revised Radar Technology, pp.262-264 (1996)”.

  FIG. 1 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 1 of the present invention. In this radar apparatus, the exciter 1a in the conventional radar apparatus shown in FIG. 19 is changed to a new exciter 1, and the signal processor 4 is changed to a new signal processor 4a. The exciter 1 converts the frequency of the pulse signal generated by a signal generator (not shown) into a frequency for transmission and sends it to the antenna 2. The signal processor 4 a includes an aperture division signal generator 41, a phase monopulse beam reformer 42, a reformed beam extractor 43, a detector 44, and an angle measurement processor 45.

First, a method of generating a Σ beam and a Δ beam generated by the power feeding circuit 23 of the antenna 2 and sent to the signal processor 4a via the first receiver 3 ₁ and the second receiver 3 ₂ will be described with reference to FIG. The description will be given with reference. Here, a case where a linear array is used will be described as a simple method for performing phase monopulse angle measurement.

As shown in FIG. 3, the received signal in the case of performing phase monopulse angle measurement can be divided into a Σ beam bσ and a Δ beam bδ and represented by the following equation.

here,
Wσn; Complex weight of the nth element of the Σ beam bσ Wδn; Complex weight of the nth element of the Δbeam bδ Aσn; Σbeam amplitude weight Aδn; Δbeam amplitude weight Θb; Beam scanning angle bσ; Σbeam bδ ; Δ beam en; nth element pattern (n = 1 to N)
dn: distance from the reference position of the n-th element (n = 1 to N)
j: imaginary unit k: wave number (2π / λ)
λ; wavelength As shown in FIG. 2, if the signal divided by the aperture is X11, X12, X21, and X22, the monopulse signal can be expressed by the following equation.

here,
Σ; Sum signal ΔAZ; AZ surface difference signal ΔEL; EL surface difference signal From the above equation (2), the aperture division signal can be calculated by the following equation.

  The aperture division signal generator 41 of the signal processor 4a generates the aperture division signals Xu and Xd by the above-described equation (3). The aperture division signals Xu and Xd generated by the aperture division signal generator 41 are sent to the phase monopulse beam reformer 42 as a phase monopulse beam.

The phase monopulse beam re-former 42 controls the phases of the aperture division signals Xu and Xd sent from the aperture division signal generator 41, and L signals having an arbitrary directivity direction (L is a positive value) according to the following equation. (Integer) phase monopulse beams (Σ beam bσr and Δ beam bδr) are reformed.

here,
d: Distance between antenna phase center and aperture-divided signal k: Wave number = 2π / λ
λ: wavelength bσr: reshaped Σ beam (l = 1 to L)
bδr: Reshaped Δ beam (l = 1 to L)
θp: Directional direction (l = 1 to L)
The Σ beam bσr and Δ beam bδr reshaped by the phase monopulse beam reformer 42 are sent to a reshaped beam extractor 43.

  The reshaped beam extractor 43 calculates the Σ beam bσr and the Δ beam bδr in the beam directing direction θp (lmax) in which the output is the maximum value among the Σ beams bσr sent from the phase monopulse beam reshaped device 42. Extract and send to detector 44.

  The detector 44 detects the target by comparing the Σ beam bσr sent from the reshaped beam extractor 43 with a predetermined threshold level, and performs angle measurement processing on the Σ beam bσr and Δ beam bδr at the time of detection. Send to vessel 45.

The angle measurement processor 45 calculates the angle measurement value by performing phase monopulse angle measurement using the Σ beam bσr and Δ beam bδr sent from the detector 46, and obtains the target angle θt. In the phase monopulse angle measurement performed by the angle measuring device 45, as shown in FIG. 5 (f), the error voltage εm obtained by the following equation is compared with a previously obtained table of reference error voltages. As a result, the target angle θt is calculated.

here,
Re []; real part *; complex conjugate Next, the operation of the radar apparatus according to the first embodiment configured as described above will be described with reference to the flowchart shown in FIG. 4 and the explanatory diagram shown in FIG. 5.

First, beam data is acquired (step S11). That is, the aperture division signal generator 41 acquires the Σ beam and the Δ beam as shown in FIG. 5A from the first receiver 3 ₁ and the second receiver 3 ₂ .

  Next, an aperture division signal is generated (step S12). That is, the aperture division signal generator 41 generates aperture division signals Xu (ΣU beam) and Xd (Σd beam) as shown in FIGS. 5B and 5C from the Σ beam and Δ beam acquired in step S11. ) And sent to the phase monopulse beam reformer 42.

  Next, beam reforming is performed (step S13). That is, the phase monopulse beam reformer 42 reshapes the phase monopulse beam using the aperture division signals Xu (ΣU beam) and Xd (Σd beam) sent from the aperture division signal generator 41. The phase monopulse beam (Σ beam bσr and Δ beam bδr) obtained by this reshaping is sent to the reshaping beam extractor 43.

  Next, the Σ level is extracted (step S14). That is, the reshaped beam extractor 43 extracts the level of the Σ beam bσr sent from the phase monopulse beam reshaped device 42 and stores it in the self.

  Next, it is checked whether or not the processing has been completed for L beams (step S15). If it is determined in step S15 that the processing has not been completed for the L beams, the beam pointing direction is then changed (step S16). Then, it returns to step S13 and the process mentioned above is repeated.

  On the other hand, when it is determined in step S15 that the processing has been completed for L beams, it is determined that L beams have been formed as shown in FIG. Extracted (step S17). That is, as shown in FIG. 5E, the reshaped beam extractor 43 outputs the maximum value from the levels of the Σ beam bσr stored in itself, and the Σ beam bσr and Δ beam in the directional direction that outputs the maximum value. bδr is extracted and sent to the angle measurement processor 45 via the detector 44.

  Next, phase monopulse angle measurement is performed (step S18). That is, the angle measurement processor 45 performs phase monopulse angle measurement using the Σ beam bσr and Δ beam bδr sent from the detector 46, and calculates the angle measurement value. Thereby, an angle measurement value in which the influence of the multipath as shown in FIG. 6B is suppressed is obtained. The process ends as described above.

  As described above, according to the radar apparatus according to Embodiment 1 of the present invention, when a direct wave and a multipath wave are received by a phase monopulse beam, a plurality of phase monopulse beams having different directivity directions are re-formed. Since the angle measurement is performed using the Σ beam and Δ beam in the directivity direction in which the output of the Σ beam is maximum, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  The radar apparatus according to the second embodiment of the present invention employs the squint angle measurement method as the angle measurement method. The squint angle measurement is described in “The Institute of Electronics, Information and Communication Engineers, Revised Radar Technology, pp. 260-262 (1996)”.

  FIG. 7 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 2 of the present invention. This radar apparatus is configured by replacing the signal processor 4a in the radar apparatus according to the first embodiment shown in FIG. 1 with a new signal processor 4b. The signal processor 4b includes an aperture division signal generator 41, a squint beam reformer 42a, a reshaped beam extractor 43a, a detector 44a, and an angle measurement processor 45a. The aperture division signal generator 41 is the same as that included in the signal processor 4a of the radar apparatus according to the first embodiment.

As shown in FIG. 8, the received signal when performing squint angle measurement can be divided into a lower beam bl and an upper beam bu, and can be expressed by the following equation.

here,
Wln; complex weight of n-th element of bl Wun; complex weight of n-th element of Bu An; amplitude weight Θsq; squint angle of bl and bu Θp; beam scanning angle bl; lower beam bu; upper beam squint beam The re-former 42a re-forms the lower beam by b1 and the beam equivalent to the upper beam bu using the phase monopulse beam. That is, the squint beam reformer 42a controls the phases of the aperture division signals Xu and Xd sent from the aperture division signal generator 41, and L squint beams having an arbitrary directivity direction are given by the following equation. (ΣL beam blr and ΣU beam bur) are reformed.

here,
d: Distance between antenna phase center and aperture-divided signal k: Wave number = 2π / λ
λ: wavelength blr: reshaped ΣL beam (l = 1 to L)
bur: Reshaped ΣU beam (l = 1 to L)
θp: Directional direction (l = 1 to L)
θsq: squint angle The ΣL beam blr and ΣU beam bur obtained by reshaping by the squint beam reformer 42a are sent to the reshaping beam extractor 43a.

  The reshaped beam extractor 43a extracts the ΣL beam blr and the ΣU beam bur in the beam directing direction θp (lmax), whose output is the maximum value, from the blr beam sent from the squint beam reshaped device 42a. And sent to the detector 44a.

  The detector 44a detects the target by comparing the blr beam sent from the reshaped beam extractor 43 with a predetermined threshold level, and detects the ΣL beam blr and ΣU beam bur at the time of detection. Send to 45a.

The angle measurement processor 45a performs squint angle measurement using the ΣL beam blr and the ΣU beam bur sent from the detector 44a, calculates an angle measurement value, and obtains a target angle θt. In the squint angle measurement performed by the angle measurement processor 45a, as shown in FIG. 10F, the error voltage εsq obtained by the following equation is compared with a reference error voltage table acquired in advance. Thus, the target angle θt is calculated.

here,
Re []; real part *; complex conjugate Next, the operation of the radar apparatus according to the second embodiment configured as described above will be described with reference to a flowchart shown in FIG. 9 and an explanatory diagram shown in FIG. 10.

First, beam data is acquired (step S21). That is, the aperture division signal generator 41 acquires the Σ beam and the Δ beam as shown in FIG. 10A from the first receiver 3 ₁ and the second receiver 3 ₂ .

  Next, an aperture division signal is generated (step S22). That is, the aperture division signal generator 41 generates aperture division signals Xu (ΣU beam) and Xd (Σd beam) as shown in FIGS. 10B and 10C from the Σ beam and Δ beam acquired in step S21. ) And sent to the squint beam reformer 42a.

  Next, beam reforming is performed (step S23). That is, the squint beam reformer 42 a reshapes a squint beam using the aperture division signals Xu (ΣU beam) and Xd (Σd beam) sent from the aperture division signal generator 41. The squint beams (ΣL beam blr and ΣU beam bur) obtained by this reshaping are sent to the reshaping beam extractor 43a.

  Next, the Σ level is extracted (step S24). That is, the reshaped beam extractor 43a extracts the level of the ΣL beam blr sent from the squint beam reshaped device 42a and stores it in the self.

  Next, it is checked whether or not the processing has been completed for L beams (step S25). If it is determined in step S25 that the processing has not been completed for the L beams, then the beam pointing direction is changed (step S26). Then, it returns to step S23 and the process mentioned above is repeated.

  On the other hand, when it is determined in step S25 that the processing has been completed for L beams, it is determined that L beams have been formed as shown in FIG. Extracted (step S27). That is, as shown in FIG. 10E, the reconstructed beam extractor 43a outputs the maximum value among the levels of the ΣL beam blr stored inside itself, and the ΣL beam blr and ΣU beam in the directional direction that output the maximum value. Bur is extracted and sent to the angle measuring processor 45a.

  Next, squint angle measurement is performed (step S28). That is, the angle measurement processor 45a performs squint angle measurement using the ΣL beam blr and the ΣU beam bur sent from the detector 44a, and calculates the angle measurement value. Thereby, an angle measurement value in which the influence of multipath as shown in FIG. The process ends as described above.

  As described above, according to the radar apparatus of the second embodiment of the present invention, when a direct wave and a multipath wave are received by a squint beam, a plurality of squint beams having different directivity directions are re-formed. Since the angle measurement is performed using the ΣL beam and the ΣU beam in the directivity direction in which the output of the ΣL beam is maximum, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  The configuration of the radar apparatus according to Embodiment 3 of the present invention is the same as that of the radar apparatus according to Embodiment 1 shown in FIG.

The radar apparatus according to the third embodiment is the same as that of the first embodiment until L phase monopulse beams are formed according to the above-described equation (4), but one phase monopulse is obtained depending on the maximum value of the output of the Σ beam. Instead of extracting the beam, the error voltage εm2 is calculated for the L phase monopulse beams by the following equation.

here,
Im []: Imaginary part When the multipath is large, the absolute value of the error voltage εm2 becomes large. Therefore, the reshaped beam extractor 43 extracts a phase monopulse beam that minimizes the error voltage of the equation (9), This is sent to the angle measurement processor 45 via the detector 44. The angle measurement processor 45 uses the phase monopulse beam (Σ beam bσr and Δ beam bδr) sent from the detector 46 to perform phase monopulse angle measurement according to the following equation and calculate an angle measurement value.

  Next, the operation of the radar apparatus according to the third embodiment will be described with reference to the flowchart shown in FIG. 11 and the explanatory diagram shown in FIG. In the following, the steps in the radar apparatus according to the first embodiment, that is, the steps for performing the same processing as the processing shown in the flowchart of FIG. 4 are denoted by the same reference numerals as those used in FIG. To do.

  First, beam data is acquired (step S11). Next, an aperture division signal is generated (step S12). Next, beam reforming is performed (step S13). That is, the phase monopulse beam reformer 42 reshapes the phase monopulse beam using the aperture division signals Xu and Xd sent from the aperture division signal generator 41, and reconfigures the Σ beam bσr and Δ beam bδr. To the reshaped beam extractor 43.

  Next, an error voltage (imaginary part) is extracted (step S31). That is, the reshaped beam extractor 43 calculates an error voltage from the Σ beam bσr and the Δ beam bδr sent from the phase monopulse beam reshaped device 42 and stores the error voltage therein.

  Next, it is checked whether or not the processing has been completed for L beams (step S15). If it is determined in step S15 that the processing has not been completed for the L beams, the beam pointing direction is then changed (step S16). Then, it returns to step S13 and the process mentioned above is repeated.

  On the other hand, if it is determined in step S15 that the processing has been completed for L beams, it is determined that L beams have been formed as shown in FIG. Are extracted (step S32). That is, the reshaped beam extractor 43, as shown in FIG. 5E, among the error voltages stored in itself, the Σ beam bσr and Δ beam bδr in the pointing direction that minimizes the error voltage. Is extracted and sent to the angle measurement processor 45 via the detector 44.

  Next, phase monopulse angle measurement is performed (step S18). That is, the angle measurement processor 45 performs phase monopulse angle measurement using the Σ beam bσr and Δ beam bδr sent from the detector 46, and calculates the angle measurement value. Thereby, an angle measurement value in which the influence of the multipath as shown in FIG. 6B is suppressed is obtained. The process ends as described above.

  As described above, according to the radar apparatus according to Embodiment 3 of the present invention, when a direct wave and a multipath wave are received by a phase monopulse beam, a plurality of phase monopulse beams having different directivity directions are re-formed. Since the angle measurement is performed using the Σ beam and Δ beam in the directivity direction in which the absolute value of the imaginary part is minimum, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  The configuration of the radar apparatus according to Embodiment 4 of the present invention is the same as that of the radar apparatus according to Embodiment 2 shown in FIG.

The radar apparatus according to the fourth embodiment is the same as that according to the second embodiment until L squint beams are formed according to the above-described equation (7). However, one squint is obtained depending on the maximum value of the output of the ΣL beam. Instead of extracting the beam, the error voltage εsq2 is calculated for the L squint beams by the following equation.

here,
Im []: Imaginary part When the multipath is large, the absolute value of the error voltage εsq2 becomes large. Therefore, the reconstructed beam extractor 43a extracts a squint beam that minimizes the error voltage of the equation (11), This is sent to the angle measurement processor 45a via the detector 44a. The angle measurement processor 45a uses the squint beam (ΣL beam blr and ΣU beam bur) sent from the detector 44a, performs squint angle measurement according to the following equation, and calculates an angle measurement value.

  Next, the operation of the radar apparatus according to Embodiment 4 will be described with reference to the flowchart shown in FIG. 12 and the explanatory diagram shown in FIG. In the following, the steps in the radar apparatus according to the second embodiment, that is, the steps for performing the same processing as the processing shown in the flowchart of FIG. 9 are denoted by the same reference numerals as those used in FIG. To do.

  First, beam data is acquired (step S21). Next, an aperture division signal is generated (step S22). Next, beam reforming is performed (step S23). That is, the squint beam reformer 42a reshapes the squint beam using the aperture division signals Xu and Xd sent from the aperture division signal generator 41, and the reconstructed ΣL beam blr and ΣU beam bur. To the reshaped beam extractor 43a.

  Next, an error voltage (imaginary part) is extracted (step S41). That is, the reshaped beam extractor 43a calculates an error voltage from the ΣL beam blr beam and ΣU beam bur sent from the squint beam reshaped device 42a, and stores the error voltage therein.

  Next, it is checked whether or not the processing has been completed for L beams (step S25). If it is determined in step S25 that the processing has not been completed for the L beams, then the beam pointing direction is changed (step S26). Then, it returns to step S23 and the process mentioned above is repeated.

  On the other hand, if it is determined in step S25 that the processing has been completed for the L beams, it is determined that L beams have been formed as shown in FIG. Are extracted (step S42). That is, as shown in FIG. 10 (e), the reshaped beam extractor 43a has a squint beam (ΣL beam blr) in the pointing direction that minimizes the error voltage from among the error voltages stored in itself. And ΣU beam bur are extracted and sent to the angle measurement processor 45a via the detector 44a.

  Next, squint angle measurement is performed (step S28). That is, the angle measurement processor 45a performs squint angle measurement using the ΣL beam blr and the ΣU beam bur sent from the detector 44a, and calculates the angle measurement value. Thereby, an angle measurement value in which the influence of multipath as shown in FIG. The process ends as described above.

  As described above, according to the radar apparatus according to Embodiment 4 of the present invention, when a direct wave and a multipath wave are received by a squint beam, a plurality of squint beams having different directivity directions are reformed. Since the angle measurement is performed using the ΣL beam and the ΣU beam in which the absolute value of the imaginary part is minimum, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  FIG. 13 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 5 of the present invention. This radar apparatus is configured by replacing the signal processor 4a in the radar apparatus according to the first embodiment shown in FIG. 1 with a new signal processor 4c. In the signal processor 4c, the reshaped beam extractor 43 is removed from the signal processor 4a of the radar apparatus according to the first embodiment, a detector 46 and a horn finder 47 are added, and a phase monopulse beam reshaped device 42 is further added. Is changed to a new phase monopulse beam reformer 42b.

  The detector 46 and the angle measuring device 47 are the same as those in the signal processor 4 of the conventional radar apparatus described with reference to FIG. The angle value calculated by the angle measuring device 47 is sent to the phase monopulse beam re-former 42b.

  The phase monopulse beam re-former 42b re-forms the phase mono-pulse beam (Σ beam and Δ beam) having a predetermined directivity direction using the aperture division signals Xu and Xd sent from the aperture division signal generator 41. Further, the reshaped phase monopulse beam is redirected in the angle measuring direction indicated by the angle measuring value sent from the angle measuring device 47. The phase monopulse beam (Σ beam and Δ beam) redirected by the phase monopulse beam reformer 42 b is sent to the detector 44.

  Next, the operation of the radar apparatus according to the fifth embodiment configured as described above will be described with reference to a flowchart shown in FIG. 14 and an explanatory diagram shown in FIG.

First, beam data is acquired (step S51). That is, the aperture division signal generator 41 acquires the Σ beam and the Δ beam as shown in FIG. 15A from the first receiver 3 ₁ and the second receiver 3 ₂ .

Next, phase monopulse angle measurement is performed (step S52). That is, the detector 46 sends detects the target by comparing come Σ beam sent from the first receiver 3 ₁ with a predetermined threshold level, the detection time of the Σ beam, the goniometer 47 . Goniometer 47, 15 as shown in (c), and calculates the Σ beam sent from the detector 46, the angle measurement values based on the Δ beam sent from the second receiver 3 ₂ The target angle θ0 is sent to the phase monopulse beam reformer 42b.

  Next, an aperture division signal is generated (step S53). That is, the aperture division signal generator 41 generates aperture division signals Xu (ΣU beam) and Xd (Σd beam) as shown in FIG. 15B from the Σ beam and Δ beam acquired in step S51, and the phase Send to monopulse beam reformer 42.

  Next, beam reforming is performed (step S54). That is, the phase monopulse beam re-former 42b reshapes the phase mono-pulse beam using the aperture division signals Xu (ΣU beam) and Xd (Σd beam) sent from the aperture division signal generator 41, and further performs measurement. The phase monopulse beam is redirected in the direction of the target angle θ0 indicated by the angle measurement value sent from the angle device 47. The phase monopulse beam (Σ beam and Δ beam) redirected by the phase monopulse beam reformer 42 b is sent to the angle measurement processor 45 via the detector 44.

  Next, angle measurement is performed (step S55). That is, the angle measurement processor 45 performs phase monopulse angle measurement using the phase monopulse beam (Σ beam and Δ beam) sent from the detector 46, and calculates the angle measurement value. In this phase monopulse angle measurement, as shown in FIG. 15 (e), the target angle θt is calculated by comparing the error voltage with a reference error voltage table acquired in advance as target information. Output to the outside.

  In the above-described example, the case where the phase monopulse angle measurement is performed has been described. However, as in the radar apparatus according to the second embodiment, the phase monopulse beam reformer 42b is replaced with a squint beam reformer. (ΣL beam and ΣU beam) are generated, and the squint beam is redirected in the angle measurement direction indicated by the angle measurement value sent from the angle measuring device 47, and the angle measurement processor 45 performs the squint angle measurement. Or it can comprise so that an amplitude comparative angle measurement may be performed.

  With the above configuration, if the target direction and the pointing direction are different in the angle measurement by the angle measuring device 47, the angle becomes an off-bore site angle where the target cannot be captured at the center of the beam, and the angle measurement accuracy deteriorates. However, since the target direction is almost known from the angle measurement value calculated by the angle measuring instrument 47, the angle of the off-bore sight is reduced by directing the reshaped beam in that direction, and highly accurate measurement is performed. Horns are possible.

  That is, according to the radar apparatus according to Embodiment 5 of the present invention, even when the pointing direction of the phase monopulse beam is deviated from the target, the Σ beam and Δ beam that direct the pointing direction toward the target direction are reformed. Thus, since the angle measurement is performed using the re-formed Σ beam and Δ beam, the influence of the multipath wave can be reduced. As a result, it is possible to measure angles with high accuracy in a multipath environment without changing the frequency of signals to be transmitted and received.

  FIG. 16 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 6 of the present invention. This radar apparatus is configured by replacing the signal processor 4a in the radar apparatus according to the first embodiment shown in FIG. 1 with a new signal processor 4d. In the signal processor 4d, the phase monopulse beam reformer 42, the reformed beam extractor 43, the detector 44, and the angle measurement processor 45 are removed from the signal processor 4a of the radar apparatus according to the first embodiment and detected. The instrument 46, the angle measuring instrument 47, and the phase angle measuring instrument 48 are added.

  The detector 46 and the angle measuring device 47 are the same as those in the signal processor 4 of the conventional radar apparatus described with reference to FIG. The angle value calculated by the angle measuring device 47 is sent to the phase angle measuring device 48.

  The phase angle finder 48 is an angle ambiguity obtained by using the angle difference value sent from the angle finder 47 and the phase difference between the aperture division signals Xu and Xd sent from the aperture division signal generator 41. The angle measurement value excluding the angle ambiguity is calculated using the angle measurement value having, and output to the outside as target information.

Here, when the aperture division signal is used, the phase at a position having a different phase center can be known, so that an angle measurement value can be obtained by the following equation.

here,
d: interval between the phase centers of the aperture division antenna Φ1: phase of the aperture division antenna 1 Φ2: phase of the aperture division antenna 2 λ: wavelength As shown in FIG. 18 (d), the angle measurement value indicates the angular ambiguity. Have. In order to eliminate this influence, if the angle measurement values of the normal Σ beam and Δ beam are used, the angle can be measured with high accuracy within a range without angular ambiguity.

  Next, the operation of the radar apparatus according to Embodiment 6 configured as described above will be described with reference to a flowchart shown in FIG. 17 and an explanatory diagram shown in FIG.

First, beam data is acquired (step S61). That is, the aperture division signal generator 41 acquires the Σ beam and the Δ beam as shown in FIG. 18A from the first receiver 3 ₁ and the second receiver 3 ₂ .

Next, phase monopulse angle measurement is performed (step S62). That is, the detector 46 sends detects the target by comparing come Σ beam sent from the first receiver 3 ₁ with a predetermined threshold level, the detection time of the Σ beam, the goniometer 47 . Goniometer 47, 18 as shown in (c), and calculates the Σ beam sent from the detector 46, the angle measurement values based on the Δ beam sent from the second receiver 3 ₂ And sent to the phase angle measuring device 48.

  Next, an aperture division signal is generated (step S63). That is, the aperture division signal generator 41 generates aperture division signals Xu (ΣU beam) and Xd (Σd beam) as shown in FIG. 18B from the Σ beam and Δ beam acquired in step S61, and the phase Send to angle measuring device 48.

  Next, angle measurement is performed using the aperture division phase (step S64). That is, the phase angle measuring device 48 is based on the phase difference between the aperture division signals Xu (ΣU beam) and Xd (Σd beam) sent from the aperture division signal generator 41, as shown in FIG. The angle measurement value is calculated.

  Next, angle values are synthesized (step S65). That is, as shown in FIG. 18 (e), the phase angle measuring device 48 receives the angle measurement value sent from the angle measuring device 47 from the angle measurement values having the angle ambiguity calculated in step S64. The angle measurement value included in a predetermined range before and after the target angle indicated by is selected and output to the outside as target information.

  As described above, according to the radar apparatus according to Embodiment 6 of the present invention, a highly accurate angle measurement value having an angle ambiguity calculated based on the phase difference between the aperture division signals formed from the Σ beam and the Δ beam. High accuracy without angle ambiguity is selected because the angle measurement value included in the specified range before and after the target angle indicated by the angle measurement value without angle ambiguity by Σ beam and Δ beam is selected. Can be obtained.

  In the first to sixth embodiments described above, the case where the present invention is applied to a radar apparatus has been described. However, the present invention is not limited to a radar apparatus, and can be applied to a receiving apparatus that performs only reception.

  The present invention can be used for radar devices, sonar devices, and the like.

1 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 1 of the present invention. It is a figure for demonstrating the production | generation method of (SIGMA) beam and (DELTA) beam in the radar apparatus which concerns on Example 1 of this invention. It is a figure for demonstrating the received signal in the case of performing a phase monopulse angle measurement in the radar apparatus which concerns on Example 1 of this invention. It is a flowchart which shows operation | movement of the radar apparatus which concerns on Example 1 of this invention. It is a figure for demonstrating operation | movement of the radar apparatus which concerns on Example 1 of this invention. It is a figure for demonstrating a mode that the influence of the multipath in the radar apparatus which concerns on Example 1-Example 4 of this invention is suppressed. It is a block diagram which shows the structure of the radar apparatus which concerns on Example 2 of this invention. It is a figure which shows the mode of the beam formation in the radar apparatus which concerns on Example 2 of this invention. It is a flowchart which shows operation | movement of the radar apparatus which concerns on Example 2 of this invention. It is a figure for demonstrating operation | movement of the radar apparatus which concerns on Example 2 of this invention. It is a flowchart which shows operation | movement of the radar apparatus which concerns on Example 3 of this invention. It is a flowchart which shows operation | movement of the radar apparatus which concerns on Example 4 of this invention. It is a block diagram which shows the structure of the radar apparatus which concerns on Example 5 of this invention. It is a flowchart which shows operation | movement of the radar apparatus which concerns on Example 5 of this invention. It is a figure for demonstrating operation | movement of the radar apparatus which concerns on Example 5 of this invention. It is a block diagram which shows the structure of the radar apparatus which concerns on Example 6 of this invention. It is a flowchart which shows operation | movement of the radar apparatus which concerns on Example 6 of this invention. It is a figure for demonstrating operation | movement of the radar apparatus which concerns on Example 6 of this invention. It is a block diagram which shows the structure of the conventional radar apparatus. It is a block diagram which shows the structure of the transmission / reception module of the conventional radar apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exciter 2 Antenna 21 Antenna element 22 Transmission / reception module 23 Feed circuit 3 ₁ 1st receiver 3 ₂ 2nd receiver 4a, 4b, 4c, 4d Signal processor 41 Aperture division signal generator 42, 42b Phase monopulse beam reconstruction 42a squint beam reformer 43, 43a reshaped beam extractor 44, 44a detector 45, 45a angle measuring processor 46 detector 47 angle measuring device 48 phase angle measuring device

Claims (6)

An aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam generated based on a received signal;
A plurality of phase monopulse beams having arbitrary directivity directions based on the aperture division signal generated by the aperture division signal generator, each of which forms a phase monopulse beam composed of a Σ beam and a Δ beam. A beam reformer;
A reshaped beam extractor for extracting a Σ beam and a Δ beam in a directional direction in which the output of the Σ beam is maximized from a plurality of phase monopulse beams reshaped by the phase monopulse beam reshaper;
An angle measurement processor that calculates an angle measurement value by phase monopulse angle measurement using the Σ beam and Δ beam extracted by the reshaped beam extractor;
A radar apparatus comprising: An aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam generated based on a received signal;
A plurality of phase monopulse beams having arbitrary directivity directions based on the aperture division signal generated by the aperture division signal generator, each of which is a squint that reshapes a squint beam composed of a ΣL beam and a ΣU beam. A beam reformer;
A reshaped beam extractor for extracting a ΣL beam and a ΣU beam in a directional direction in which the output of the ΣL beam is maximum from a plurality of squint beams reshaped by the squint beam reshaper;
An angle measurement processor that calculates an angle value by squint angle measurement using the ΣL beam and the ΣL beam extracted by the reshaped beam extractor;
A radar apparatus comprising: An aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam generated based on a received signal;
A plurality of phase monopulse beams having arbitrary directivity directions based on the aperture division signal generated by the aperture division signal generator, each of which forms a phase monopulse beam composed of a Σ beam and a Δ beam. A beam reformer;
A reshaped beam extractor that extracts a Σ beam and a Δ beam that minimize the absolute value of the imaginary component of the error voltage from a plurality of phase monopulse beams reshaped by the phase monopulse beam reshaper;
An angle measurement processor that calculates an angle measurement value by phase monopulse angle measurement using the Σ beam and Δ beam extracted by the reshaped beam extractor;
A radar apparatus comprising: An aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam generated based on a received signal;
A plurality of phase monopulse beams having arbitrary directivity directions based on the aperture division signal generated by the aperture division signal generator, each of which is a squint that reshapes a squint beam composed of a ΣL beam and a ΣU beam. A beam reformer;
A reshaped beam extractor that extracts a ΣL beam and a ΣU beam that have the smallest absolute value of the imaginary component of the error voltage from a plurality of squint beams reshaped by the squint beam reshaper;
An angle measurement processor that calculates an angle value by squint angle measurement using the ΣL beam and the ΣL beam extracted by the reshaped beam extractor;
A radar apparatus comprising: A goniometer that measures angles based on a Σ beam and a Δ beam generated based on a received signal;
An aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam generated based on a received signal;
Based on the aperture division signal generated by the aperture division signal generator, a phase monopulse beam composed of a Σ beam and a Δ beam having a predetermined directivity is re-formed, and further according to an angle measurement value from the angle measuring device. A phase monopulse beam reformer for redirecting the phase monopulse beam;
An angle measurement processor that calculates an angle measurement value by phase monopulse angle measurement using the Σ beam and the Δ beam redirected by the phase mono pulse beam reformer;
A radar apparatus comprising: A goniometer that measures angles based on a Σ beam and a Δ beam generated based on a received signal;
An aperture division signal generator that generates an aperture division signal from a Σ beam and a Δ beam generated based on a received signal;
Of the angle values having ambiguity calculated based on the phase difference of the aperture division signal generated by the aperture division signal generator, the target angle indicated by the angle value measured by the angle meter A phase angle measuring device for selecting angle measurement values included in a predetermined range before and after,
A radar apparatus comprising:

Images