JP2011149916A - Radio wave receiver and arrival direction measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio wave receiver capable of measuring arrival direction of the received radio wave at high precision without enlargement of hardware scale. <P>SOLUTION: In the radio wave receiver, a controlling section 16 performs selectively both the control of rough angle measurement, which makes the antenna selectors 9 to 12 to select the received waves from antennas 4, 8, 2, and 6 of azimuthal directions and vertical directions and also makes a signal processing section 15 to compute azimuthal rough angle measurement and vertical rough angle measurement by using mono-pulse mode, and the control of precision angle measurement, which makes antenna selectors 9 to 12 to switch between the received waves from azimuthal direction antennas 4, 8, 3, and 7 and the received wave from antennas 1, 5, 2, and 6 corresponding to vertical direction in order to force selection and also makes the signal processing section 15 to compute azimuthal precision angle measurement and vertical precision angle measurement of the arrival direction by using mono-pulse mode together with interferometer mode. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radio wave receiving apparatus and an arrival direction measuring method that are mounted on a flying object and measure the arrival direction of a received radio wave, for example.

  In general, when obtaining the direction of the source of an incoming radar wave, there are methods of measuring angles using an amplitude monopulse method, a phase monopulse method, and an interferometer method. A radio wave receiver mounted on a flying object receives radio waves with a pair of receiving antennas installed in front of the flying object, and measures the direction of arrival of the radio wave by an amplitude monopulse method or an interferometer method.

  Since the interferometer method measures the arrival direction based on the phase information of the radio wave, it is known that the interferometer method is more accurate than the amplitude monopulse method that measures the arrival direction based on the amplitude information of the radio wave. However, since the flying object has a shape with a sharp radome, the phase disturbance due to the change in the arrival direction of the received wave due to the influence is large, and the accurate arrival direction cannot be measured by the interferometer method.

  On the other hand, the amplitude monopulse method has a measurement accuracy lower than that of the interferometer method, and thus the accuracy required for flying the flying object cannot be obtained. Therefore, a method has been proposed in which the number of antennas is increased and the accuracy is improved by obtaining an optimal solution of a combination of a plurality of antennas (see, for example, Patent Document 1).

JP-A-8-5734

  However, according to the method of Patent Document 1, the accuracy can be increased by increasing the number of antennas installed and obtaining an optimal solution of a combination of a plurality of antennas, but there is a problem that the hardware scale increases. The flying object needs to have a simple structure from the viewpoint of miniaturization, and the technique of Patent Document 1 is not suitable for the radio wave receiver of the flying object.

  The present invention has been made paying attention to the above circumstances, and its object is to provide a radio wave receiving apparatus and an arrival direction measuring method capable of measuring the arrival direction of a received radio wave with high accuracy without increasing the hardware scale. Is to provide.

  In order to achieve the above object, one aspect of the present invention is a radio wave receiver that is mounted on a flying object and measures the arrival direction of a received radio wave, and is paired on an azimuth direction and an elevation axis. In this way, a plurality of first antenna elements arranged at the outer edge of the antenna surface, a plurality of second antenna elements arranged near each of the first antenna elements, and reception by the first antenna element A plurality of antenna selectors for selecting one of the received first received wave and the second received wave received by the second antenna element, and the received wave selected by the antenna selector A receiver that performs reception processing, a rough angle measurement process that calculates an azimuth coarse angle and a high and low coarse angle in the direction of arrival using an amplitude monopulse method based on a signal from the receiver, and the amplitude monopulse method And A signal processing unit that selectively performs precision angle processing for calculating the azimuth and elevation accuracy of the direction of arrival using an interferometer method, and the antenna selector in the orientation and elevation direction First control for selecting the corresponding second received wave and causing the signal processing unit to perform the rough angle measurement processing, and the first and second reception corresponding to the azimuth direction for the antenna selector. And a control unit that performs switching and selection between the first and second received waves corresponding to the height direction and the second control for causing the signal processing unit to perform the precise angle processing. A radio wave receiver characterized by the above is provided.

  Another aspect of the present invention is an arrival direction measuring method used in a radio wave receiver that is mounted on a flying object and measures the arrival direction of a received radio wave. Radio waves are received by a plurality of first antenna elements arranged at the outer edge of the antenna surface so as to form a plurality of second antenna elements respectively arranged in the vicinity of the first antenna element, Of the first received wave received by the first antenna element and the second received wave received by the second antenna element, select the second received wave corresponding to the azimuth and elevation direction, A reception process is performed on the selected second received wave, and an azimuth rough angle and a high / low rough angle of the arrival direction are calculated using an amplitude monopulse method based on the signal subjected to the reception process. Rough angle measurement Among the first received wave and the second received wave, the first and second received waves corresponding to the azimuth direction and the first and second received waves corresponding to the elevation direction. Select by switching, perform reception processing on the selected first and second received waves, and use the amplitude monopulse method and interferometer method together based on the signal subjected to the reception processing There is provided an arrival direction measuring method characterized by selectively performing an azimuth measuring angle and a precise angle processing for calculating a high and low accuracy angle in the direction of arrival.

  Therefore, according to the present invention, it is possible to provide a radio wave receiver and an arrival direction measuring method capable of measuring the arrival direction of a received radio wave with high accuracy without increasing the hardware scale.

The functional block diagram which shows the structure of one Embodiment of the electromagnetic wave receiver which concerns on this invention. The figure which shows the example of antenna arrangement | positioning seen from the front direction of the flying body. The figure which looked at the antenna surface of FIG. 2 from the upper side. The figure which looked at the antenna surface of FIG. 2 from the right side. The flowchart which shows the procedure of the arrival direction measurement process, and its content.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of a radio wave receiver mounted on the flying object of this embodiment.

  This flying object radio wave receiving apparatus includes antennas TI1, antenna TM2, antenna LI3, antenna LM4, antenna BI5, antenna BM6, antenna RI7 and antenna RM8, antennas TI1 and antennas LM4 to 1 that receive radio waves from other radars. An antenna selector A9 that selects one antenna, an antenna selector B10 that selects one antenna from the antenna BI5 and the antenna RM8, an antenna selector C11 that selects one antenna from the antenna LI3 and the antenna TM2, and an antenna RI7 and An antenna selector D12 that selects one antenna from the antenna BM6, a receiver 13 that detects a received wave of the antenna selected by each antenna selector, and an A / D conversion that converts the detected received wave into a digital signal 14 and digital It comprises a signal processing unit 15 for determining the direction of the reception wave from the items, and a controller 16 for instructing the selection of the angle measuring process and frequency.

  The antenna TI1, the antenna TM2, the antenna LI3, the antenna LM4, the antenna BI5, the antenna BM6, the antenna RI7, and the antenna RM8 are assumed to have the same size and the same performance. The antenna TI1, the antenna LI3, the antenna BI5, and the antenna RI7 are used when measuring the arrival direction based on the phase information of the radio wave by the interferometer method (precise angle processing). The antenna TM2, the antenna LM4, the antenna BM6, and the antenna RM8 are used when uniquely measuring the direction of arrival (rough angle measurement processing) although the accuracy is low by the interferometer method by the amplitude monopulse method.

  FIG. 2 shows an antenna arrangement example as seen from the front direction of the flying object. As shown in FIG. 2, the antenna is disposed at the outer edge of the antenna surface provided in the front portion of the flying body. The antenna TI1, the antenna LI3, the antenna BI5, and the antenna RI7 are all arranged in pairs on the azimuth and elevation axes in the front direction. Antenna TM2, antenna LM4, antenna BM6, and antenna RM8 are arranged in the vicinity of antenna TI1, antenna LI3, antenna BI5, and antenna RI7, respectively.

  FIG. 3 shows a view of the antenna surface from the upper side and a view of the antenna surface from the right side. As shown in FIG. 3, when the antenna surface is viewed from the upper side, the antenna TM <b> 2 is disposed at an angle with the antenna BM <b> 6 facing upward and the antenna BM <b> 6 downward. When the antenna surface is viewed from the right side as shown in FIG. 4, the antenna LM4 is arranged at a slight angle in the left direction and the antenna RM8 is arranged in a right direction. This is to obtain a received signal for performing the amplitude monopulse method. The tilt angle is about half of the beam width of the antenna from the principle of the amplitude monopulse system. At this time, the range in which the angle can be measured is about the beam width.

  The signal processing unit 21 detects a radar wave from the digital signal, and outputs a digital signal to the rough angle processor 153 or the precise angle processor 154 according to an instruction from the controller 16. The processing selector 152, the coarse angle measuring unit 153 that obtains the direction of the received wave using the amplitude monopulse method, and the precision that obtains the direction of the received wave using the interferometer method with higher accuracy than the rough angle measuring unit 153. Angle measuring processor 154.

FIG. 5 is a flowchart showing the procedure and contents of the arrival direction measurement process in this radio wave receiving apparatus.
In S <b> 1, the controller 16 outputs an instruction of “rough angle measurement” or “fine angle measurement” to the antenna selectors A <b> 9 to D <b> 12 and the angle measurement process selector 152. When the instruction of “rough angle measurement” is issued from the controller 16, the process of S2 to S6 is performed, and when the instruction of “precision angle” is issued, the process of S7 to S12 is performed. The instructions for the coarse angle and the precise angle in the controller 16 are a method of performing the precise angle immediately after the radio wave is detected in the coarse angle, and the process of the coarse angle is repeated by changing the frequency, There is a method in which a plurality of approximate directions and frequencies of a radio wave transmission source are obtained for a wide range of frequencies, and then a precise angle is repeated for each frequency.

(Coarse angle measurement)
In the coarse angle reception / detection process S2, when the antenna selector A9 to the antenna selector D12 receive an instruction of “rough angle measurement” from the controller 16, the antenna selector A9 receives the antenna LM4, and the antenna selector B10 The antenna RM8, the antenna selector C11 selects the antenna TM2, and the antenna selector D12 selects the antenna BM6. The received waves from the respective antenna selectors are referred to as received wave A, received wave B, received wave C, and received wave D.

  The reception waves A to D are detected at the frequency instructed by the controller 16 in the receiver 13, and become reception analog signals A to D. Since the phase information is not used in the rough angle measurement process, the frequency band can be widened. The A / D converter 14 converts the received analog signals A to D into digital signals A to D. The detection processor 151 outputs a detection result indicating “detected” when the amplitude value of the digital signals A to D exceeds the threshold value. When the threshold value is not exceeded, a detection result indicating “no detection” is output to the controller 16.

  In S3, when “detected” is input from the detection processor 151 to the controller 16, the controller 16 instructs the processing of S4 and S5, and when “not detected” is input, the processing ends. To do.

In the rough angle measurement range determination process S4, the angle measurement processing selector 152 outputs the digital signals A to D to the rough angle measurement processor 153. The coarse angle measuring processor 153 is the values of Σ _A = (A _A + A _B ) and Δ _A = (A _A −A _B ) when the amplitude values of the digital signal A and the digital signal B are A _A and A _B , respectively. and when the digital signal C, and the amplitude value of the digital signal D to the _{a C, a D, Σ E} = (a C + a D), Δ E = (a C -A D) of values respectively obtained. Crude angle measurement range discriminant These values _{N A = Σ A -K NA ·} Δ A, N E = calculating the Σ _E -K _NE · Δ _E. In principle, Σ _A > Δ _A and Σ _E > Δ _E within the rough measurement angle range. Therefore, when both N _A and N _E are equal to or greater than 0, it is determined as “in range”, and otherwise is determined as “out of range”. . K _NA and K _NE are coefficients for correcting the antenna characteristics.

  In S5, when the determination result of S4 is “within range”, the process proceeds to S6, and the rough angle processor 153 outputs the determination result indicating “within range” and the frequency to the controller 16. On the other hand, when the determination result of S4 is “out of range”, the rough angle measurement processor 153 outputs a determination result indicating “out of range” to the controller 16, and the controller 16 ends the processing.

In the rough angle measurement process S6, the rough angle measurement processor 153 performs amplitude monopulse processing as shown below, and obtains the rough measured angle values (the azimuth rough measured angle value θ _MA and the high and low rough measured angle value θ _ME ) of the received wave. Ask. The calculation of the azimuth rough angle value θ _MA and the high and low rough angle value θ _ME can be processed in parallel.

The coarse azimuth angle value is θ _MA = K _MA · Δ _A / Σ _{A where} the error angle coefficient is K _MA . Height roughness measured angle value, when the error angle coefficient is _{K ME,} the _{θ ME = K ME · Δ E} / Σ E. K _MA and K _ME are determined by instructions from the controller 16.

(Precision angle processing)
Since the precise angle measurement process uses both the amplitude monopulse method and the interferometer method, the received wave corresponding to the azimuth direction and the received wave corresponding to the height direction are switched and selected. In FIG. 5, S7 to S9 indicate azimuth angle processing, and S10 to S12 indicate elevation angle processing.

  In the azimuth reception / detection processing S7, the antenna selector A9 to the antenna selector D12 receive an instruction of “azimuth of precise azimuth” from the controller 16, and the antenna selector A9 receives the antenna LM4 and the antenna selector B10 receives the antenna. RM8, antenna selector C11 selects antenna LI3, and antenna selector D12 selects antenna RI7. The received waves from the respective antenna selectors are defined as a received wave A1, a received wave B1, a received wave C1, and a received wave D1.

  The reception waves A1 to D1 are detected by the receiver 13 at the frequency designated by the controller 16, and become reception analog signals A1 to D1. The frequency is instructed to be output from the coarse angle processor 153. The A / D converter 14 converts the received analog signals A1 to D1 into digital signals A1 to D1. The detection processor 151 detects a received wave when the amplitude values of the digital signals A1 to D1 exceed a threshold value, and outputs a detection result “detected” to the controller 16. When the threshold value is not exceeded, a detection result “no detection” is output to the controller 16.

  In S <b> 8, the controller 16 performs the process of S <b> 9 when “detected” is input, and ends the process when “not detected” is input.

In the azimuth precise angle processing S <b> 9, the angle measurement processing selector 152 outputs the digital signals A <b> 1 to D <b> 1 to the precise angle processor 154. The precise angle processor 154 performs the amplitude monopulse process and the interferometer process in parallel, and obtains the azimuth angle value θ _IA of the received wave from both results.

The amplitude monopulse processing performs the following processing. When the amplitude values of the digital signal A1 and the digital signal B1 are A _A1 and A _B1 , Σ _A1 = (A _A1 + A _B1 ) and Δ _A1 = (A _A1 −A _B1 ) are obtained. When the error angle coefficient is K _MA1 , θ _MA1 = K _MA1 · Δ _A1 / Σ _A1 .

The interferometer processing performs the following processing. When the phase values of the digital signal C1 and the digital signal D1 are φ _C and φ _D , the element interval between the antenna LI3 and the antenna RI7 is d _A [m], the frequency of the received wave is f [Hz], and the speed of light is c, θ _IA = Sin ⁻¹ ((φ _C −φ _D ) · c / (2π · f · d _A )).

In the amplitude monopulse processing, the angle is uniquely determined, but the accuracy is lower than that of the interferometer processing. On the other hand, the interferometer processing can take a plurality of angle values from the periodicity of the sin function. Therefore, θ _IA is the closest to θ _MA1 among a plurality of solutions.

  In the high / low angle reception / detection processing S10, the antenna selector A9 to the antenna selector D12 receive an instruction of “high / low precision angle” from the controller 16, and the antenna selector A9 receives the antenna TI1 and the antenna selector B10 receives the antenna. BI5 is selected, antenna TM2 is selected by antenna selector C11, and antenna BM6 is selected by antenna selector D12. The received waves from the respective antenna selectors are referred to as received wave A2, received wave B2, received wave C2, and received wave D2.

  The reception waves A2 to D2 are detected by the receiver 13 at the frequency designated by the controller 16, and become reception analog signals A2 to D2. The frequency is instructed to be output from the coarse angle processor 153. The A / D converter 14 converts the received analog signals A2 to D2 into digital signals A2 to D2. The detection processor 151 detects a received wave when the amplitude values of the digital signals A2 to D2 exceed a threshold value, and outputs a detection result “detected” to the controller 16. When the threshold value is not exceeded, a detection result “no detection” is output to the controller 16.

  In S <b> 11, the controller 16 performs the process of S <b> 10 when “detected” is input, and ends the process when “not detected” is input.

In the high / low precision angle measurement process S <b> 12, the angle measurement process selector 152 outputs the digital signals A <b> 2 to D <b> 2 to the precision angle processor 154. The precise angle processor 154 performs the amplitude monopulse process and the interferometer process in parallel, and obtains the high and low precision angle value θ _IE of the received wave from both results.

The amplitude monopulse processing performs the following processing. When the amplitude values of the digital signal C2 and the digital signal D2 are A _C2 and A _D2 , Σ _E2 = (A _C2 + A _D2 ) and Δ _E2 = (A _C2 -A _D2 ) are obtained. Assuming that the error angle coefficient is K _ME2 , the measured angle value θ _ME2 = K _ME2 · Δ _E2 / Σ _E2 .

The interferometer processing performs the following processing. When the phase values of the digital signal A2 and the digital signal B2 are φ _A and φ _B , the element interval between the antenna TI3 and the antenna BI7 is d _E [m], the frequency of the received wave is f [Hz], and the speed of light is c, θ _IE = Sin ⁻¹ ((φ _A −φ _B ) · c / (2π · f · d _E )).

In the amplitude monopulse processing, the angle is uniquely determined, but the accuracy is lower than that of the interferometer processing. On the other hand, the interferometer processing can take a plurality of angle values from the periodicity of the sin function. Therefore, θ _IE is the closest to θ _ME2 among a plurality of solutions.

  According to the above-described embodiment, when obtaining the direction of a radar wave transmission source that is generally present, an outline of a received wave can be obtained by using only amplitude information that is relatively less affected by a radome even in an antenna having a sharp radome. The azimuth angle and elevation angle can be obtained simultaneously, and after narrowing the frequency range, the arrival direction of the received wave can be obtained accurately by angle measurement of phase information more accurate than angle measurement based on amplitude information.

  The coarse angle can be obtained simultaneously by the azimuth angle and the elevation angle by the amplitude monopulse method. The precise measurement angle can be uniquely determined by one observation by using both the amplitude monopulse method and the interferometer method.

  In addition, the received waves of different antennas are used for the coarse angle and the precise angle, but this can be realized with a small hardware scale without increasing the number of reception channels by switching the antenna selector. In addition, since the antenna arrangement as shown in FIG. 2 is used, a space is created in the central portion of the antenna surface. For example, an active array antenna can be further arranged on the same antenna surface.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  DESCRIPTION OF SYMBOLS 1-8 ... Antenna, 9-12 ... Antenna selector, 13 ... Receiver, 14 ... A / D converter, 15 ... Signal processing part, 151 ... Detection processor, 152 ... Angular measurement selector, 153 ... Coarse Angle measuring processor, 154... Precision angle measuring device, 16.

Claims (3)

A radio wave receiver that is mounted on a flying object and measures the direction of arrival of received radio waves,
A plurality of first antenna elements disposed on the outer edge of the antenna surface so as to form a pair on the azimuth and elevation axes,
A plurality of second antenna elements respectively disposed in the vicinity of the first antenna element;
A plurality of antenna selectors for selecting one of a first received wave received by the first antenna element and a second received wave received by the second antenna element;
A receiver that performs reception processing on the received wave selected by the antenna selector;
Based on a signal from the receiver, a rough angle measurement process that calculates an azimuth rough angle and a high and low rough angle of the arrival direction using an amplitude monopulse method, and the amplitude monopulse method and an interferometer method are used in combination. A signal processing unit that selectively performs precision angle processing for calculating the azimuth and angle accuracy of the direction of arrival.
A first control for causing the antenna selector to select the second received wave corresponding to the azimuth and elevation direction, and causing the signal processing unit to perform the rough angle measurement process; and causing the antenna selector to perform the azimuth direction. The first and second received waves corresponding to and the first and second received waves corresponding to the height direction are switched and selected, and the signal processing unit performs the precise angle processing. And a control unit that controls the radio wave receiving apparatus.   2. The radio wave receiving apparatus according to claim 1, wherein the second antenna element is arranged with a preset angle outward from the antenna front direction. A direction-of-arrival measurement method used in a radio wave receiver that is mounted on a flying object and measures the direction of arrival of a received radio wave,
A plurality of first antenna elements arranged on the outer edge of the antenna surface so as to form a pair on the azimuth and elevation axes, and a plurality of second antenna elements arranged in the vicinity of the first antenna element, respectively. Receive radio waves with the antenna element of
A second received wave corresponding to the azimuth and elevation direction is selected from the first received wave received by the first antenna element and the second received wave received by the second antenna element. , Applying a reception process to the selected second received wave, and based on the signal subjected to the reception process, an azimuth rough angle and a high / low rough angle in the direction of arrival using an amplitude monopulse method The first and second received waves corresponding to the azimuth direction of the first received wave and the second received wave and the first and second corresponding to the elevation direction of the rough angle calculation process to be calculated. A second received wave is selected by switching, a reception process is performed on the selected first and second received waves, and the amplitude monopulse method and the interferometry are based on the signal subjected to the reception process. Combining with the ferrometer method DOA measurement method for the precise measurement angle processing for calculating the azimuth precision angle measuring and height precision angle measuring of said selectively be performed.

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