JP2009300161A - Radio detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a conventional radio direction detector takes a too long period of time, since it sequentially carries out a direction finding operation for respective small coverage areas partitioned in all directions, and especially if a countervailing incoming radio wave significantly changes its reception level at each pulse, incorrect direction finding occurs while carrying out the partitioning direction finding, and furthermore the conventional radio direction detector is made large-sized, since the number of receivers and the number of RF cables reaching the receivers are large. <P>SOLUTION: A radio detector is equipped with; an array antenna 2 made up by arranging antenna elements 6 in an arrayed form at respective small coverage areas partitioned in all directions; a switch 3 for switching/connecting a reception signal of the antenna element; a receiver 4 for measuring an amplitude, a frequency and a phase of the reception signal connected to each switch 3; and a direction finding processor 5 having a coarse direction-finding function of specifying the array antenna 2 in the most facing states in a rough incoming direction on the basis of the amplitude of the reception signal connected to the receiver 4, and a fine direction-finding function of minutely computing the incoming direction on the basis of the frequency and phase of a signal received by the element 6 of the specified array antenna 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an azimuth detection device that is mounted on a mobile body such as a ship and detects the azimuth of an RF signal radio wave.

  For example, Patent Documents 1 and 2 describe conventional radio wave detection devices. In the conventional example shown in Patent Document 1, a set is first selected from an antenna array obtained by dividing an omnidirectional coverage area into four parts, and then one set is selected in order, and an approximate arrival direction is estimated by capturing incoming radio waves. "Rough search" was performed.

  In the conventional example shown in Patent Document 2, a plurality of antenna elements are arranged on the circumference in order to detect an omnidirectional coverage, a circular antenna is formed, and a receiver connected corresponding to each of the plurality of antenna elements To capture the radio wave received by the antenna element, and to form a set of sum and difference patterns by changing the boresight direction, thereby reducing the probability of incorrect calculation of the incoming radio wave incident angle. It was.

JP-A-11-23687 (FIGS. 5 and 6) JP-A-8-166433 (FIGS. 3 and 7)

  Conventional radio wave detectors have the following problems. In the conventional example shown in Patent Document 1, there is a problem that it takes time to detect all directions (four sets) because the incoming radio waves are received by switching one set at a time. Further, when the reception level of the incoming radio wave to be opposed changes greatly for each pulse, the reception level changes during the divided reception four times, so that it is impossible to search. In other words, there is a problem that there is a high possibility of misdetection unless all directions are detected simultaneously.

  Further, in the conventional example shown in Patent Document 2, the number of receivers to be connected corresponding to each antenna element is required by the number of antenna elements, the number of receivers and the number of RF cables to the receiver are increased, and the scale is large. There was also a problem of becoming. In particular, the antenna of a radio wave detection device mounted on a ship is often installed on the top of the mast, so it is difficult to lay a large number of cables, and space saving is indispensable.

  The present invention has been made to solve the above-described problems, and can detect all directions at the same time, is space-saving, downsized, and has a BIT (Built In Test) function. The purpose is to provide.

  According to a first aspect of the present invention, there is provided a radio wave detection apparatus including a plurality of array antennas each having an antenna element arranged in an array for each small cover area obtained by dividing the entire circumference into a plurality of small cover areas, and at least a set of the array antennas. A plurality of switches configured to switch and connect signals received by the antenna elements, and a plurality of switches for measuring the amplitude, frequency, and phase of signals received by the antenna elements connected to the switches. The set of array antennas that face the signal arrival direction is determined from the amplitude of the signal received by the antenna element selected for each set of array antennas connected to the receiver by switching the switch. The rough search function and the switch corresponding to the identification, the frequency and phase difference of the signal received by the antenna elements of the specified array antenna It is characterized in that a person probe processor and a fine side probe function calculates the arrival direction.

  The radio wave detector according to the second invention is characterized in that the number of antenna elements arranged in an array on the array antenna is smaller than the number of sets of array antennas.

  In the radio wave detector according to the third aspect of the invention, four sets of array antennas are formed on each side of a square shape, and each set of array antennas has two common antenna elements and sides arranged at the apexes of the square shape. It is comprised by the separate antenna element arrange | positioned in this.

  According to a fourth aspect of the present invention, there is provided a radio wave detection apparatus that performs a plurality of sets of coarse searches using different antenna elements of each array antenna for incoming radio waves transmitted from a radio wave transmission source at a known transmission position. It is provided with a function of identifying a failed antenna element by comparing a set of array antennas most facing in the signal arrival direction specified by the method and a known transmission position of the radio wave transmission source. It is what.

  The present invention has been made to solve the above problems. According to the first aspect of the present invention, a “rough search” is performed to simultaneously receive all directions and estimate the approximate direction of arrival of radio waves, and the arrival of radio waves in detail using the antenna element of the array antenna that faces most in the direction. By performing "Finding" that measures the azimuth, the probability of false detection can be reduced compared to the conventional method, and the direction finding performance can be improved, and by reducing the number of receivers and RF cables, the size and cost can be reduced. Can be

  According to the second invention, by reducing the number of antenna elements, the cost can be reduced and the space can be saved, and the number of switching elements from the rough search to the fine search is reduced, so that the switch is simplified.

  According to the third invention, by changing the arrangement of the antenna elements and reducing the number of elements further than the second invention, the cost can be reduced and the space can be saved, and the switching element from the rough search to the fine search Since the number is reduced, the switch is simplified.

  According to the fourth invention, by using the rough search as the BIT function, the failed antenna element can be specified while the present apparatus is still incorporated.

Example 1.
FIG. 1 is a schematic diagram showing a configuration of a radio wave detection apparatus according to a first embodiment of the present invention. The schematic configuration includes a direction searching antenna 1, an array antenna 2, a switch 3, a receiver 4, a direction searching processor 5, and an antenna element 6. Has been. FIG. 2 is a schematic configuration diagram of the direction finding antenna 1. The direction finding antenna 1 includes four sets of array antennas 2 obtained by dividing the coverage of 360 degrees in all directions, for example, into four. One set of array antennas 2 is composed of, for example, four antenna elements 6.

  FIG. 5 is an example of a switch system diagram according to the first embodiment. In accordance with the instruction signal from the direction finding processor 5, the switch 3 has two types of direction finding functions ("roughness search" that estimates the approximate direction of arrival of radio waves and "precise direction" that measures the arrival direction of the incoming radio waves in detail. The antenna element 6 is switched and selected by searching. The receiver 4 detects the radio wave received by the four antenna elements 6, converts the detected signal into a video signal, and outputs the video signal. The direction search processor 5 performs rough direction search and fine direction search, analyzes a signal related to each antenna element 6 output from the receiver 4, and calculates the arrival direction of the radio wave radiated from the object. .

  FIG. 3 is a conceptual diagram of two types of method searching methods implemented in this embodiment. In order to detect the entire coverage area, a coarse search that estimates the approximate direction of arrival of radio waves simultaneously using four sets of array antennas, and a set of array antennas that face the direction of arrival are selected in detail. Performs a precision search to measure the direction of arrival. It is a device that switches between these two types of direction finding and accurately detects the direction of incoming radio waves.

  FIG. 4 is an example of a selection logic table for each of the switches 3-1 to 3-4 of the radio wave detector according to the present embodiment. First, FIG. 4-1 shows a case where rough search is performed. Since all four sets of array antennas 2 are used simultaneously, the switch 3 is connected to the third (or even second) antenna element near the center of each array antenna 2. Here, “method A” means a case where a method is searched for using the array antenna 2-A set. In the rough search, no matter which set of array antennas 2 from 2-A to 2-D is searched for, the same antenna element is always connected. For example, the switch 3-1 is always connected to the antenna element A-3.

  Next, Fig. 4-2 shows a case where a refinement search is performed. The set of array antennas 2 that faces the direction of arrival of the radio wave calculated by the rough search is identified from 2-A to 2-D, and the corresponding search is selected from the search A to the search D. Switches the switches 3-1 to 3-4. In addition, what is shown in italics in the figure is a case where the same antenna element is used even when switching from coarse search to fine search. For example, the switch 3-1 is connected to A-3 in the rough search, and is connected to the same A-3 even when switching to the fine search. From this figure, for example, the switch 3-1 is switched and connected to any one of the four antenna elements A-3, B-4, C-1, and D-2 by the search case, and switched to the other elements. It is understood that it is not done. This is also represented as a connection destination of the switch 3-1 in the switch system diagram of FIG. 5.

  Next, the operation will be described. The purpose of this radio wave detection apparatus is to detect a radio wave early when a radio wave is radiated from an opposing radar facility or the like. An example of a procedure for detecting the arrival direction of the radio wave is shown in the flowchart of FIG. ing. First, one antenna element 6 is selected from each of the four sets of array antennas 2 obtained by dividing all directions into four, and the four elements are received simultaneously. The antenna element 6 is selected in accordance with the switch selection table in FIG. The array antenna 2 has 4 sets (2-A set, 2-B set, 2-C set, 2-D set), and the antenna elements 6 of each array antenna 2 (2-A set includes A-1, A-2). , A-3, A-4 / 2-B set B-1, B-2, B-3, B-4 / 2-C set C-1, C-2, C-3, C-4 / 2-D set of D-1, D-2, D-3, D-4), for example, A-3, B-3, C-3, D-3 which are antenna elements 6 near the center A total of four are selected and received from all coverage areas.

  The receiver 4 detects the radio wave received by each antenna element 6, converts the detected signal into a video signal, and outputs the video signal. The signal level of the video signal (the amplitude of the radio wave received by the four antenna elements 6) related to each antenna element 6 output from the receiver 4 is analyzed by the probing processor 5, and the object radiates. The approximate arrival direction of the radio wave is calculated, and the array antenna 2 that faces the direction is identified. This is called “rough search”. For example, specifically, the levels of four video signals are compared, the directivity direction of the antenna element corresponding to the video signal having the highest level is calculated, and the approximate arrival direction of the incoming radio wave is obtained.

  Next, the direction processor 5 selects the array antenna 2 that faces the approximate arrival direction calculated above, switches the connection of the switch 3, and receives incoming radio waves by the antenna elements 6 (four) of the array antenna 2. Capture and receive. Specifically, for example, as shown in FIG. 4B, when the array antenna 2-B set (search B) is selected, the switch 3-4 switches to B-1 of the antenna element 6, and B-2 Switch 3-3, switch B-3, switch 3-2 and switch B3-1 corresponding to B-4, respectively, and the array antenna 2-B set is selected.

  When the plurality of antenna elements 6 receive the same incoming radio wave, a phase difference is generated between the plurality of antenna elements according to the direction of arrival, so that the direction of arrival can be calculated from the phase difference. FIG. 7 shows the principle of calculating the direction of arrival from the phase difference. When radio waves arrive at two antenna elements separated by a distance d from the direction of the angle θ, the arrival direction can be calculated from the following equation, where ΔΦ is the phase difference of the incoming radio waves.

ここで、λは、到来電波の波長である。受信機４は、複数のアンテナ素子６が対象の放射する電波を受信すると、その電波をフーリエ変換して周波数信号を出力する。方探処理機５は、受信機４より出力された周波数信号から各アンテナ素子６により受信された電波の位相差を算出し、周波数信号と位相差から対象が放射している電波の詳細な到来方位を算出する。これを『精方探』と呼ぶ。

Here, λ is the wavelength of the incoming radio wave. When the plurality of antenna elements 6 receive radio waves radiated from the target, the receiver 4 performs a Fourier transform on the radio waves and outputs a frequency signal. The direction finding processor 5 calculates the phase difference of the radio wave received by each antenna element 6 from the frequency signal output from the receiver 4, and the detailed arrival of the radio wave radiated by the object from the frequency signal and the phase difference. Calculate the bearing. This is referred to as “Seiki hun”.

Example 2
FIG. 8 shows a schematic diagram of an antenna of a radio wave detector according to Embodiment 2 of the present invention. In the first embodiment, there are four array antennas 2 (2-A group, 2-B group, 2-C group, 2-D group), and there are four antenna elements 6 constituting each array antenna 2, and the same number. However, even when the number of the array antennas 2 and the antenna elements 6 is not necessarily the same, it is possible to perform the direction search by switching between the rough direction search and the fine direction search by changing the way of assembling the switches.

  In the second embodiment, as shown in FIG. 8, there are four sets of array antennas 2 (2-A set, 2-B set, 2-C set, 2-D set), and the antenna elements constituting each array antenna 2 are 4 to 3 (2-A set A-1, A-2, A-3 / 2-B set B-1, B-2, B-3 / 2-C set C-1, C-1 -2, C-3 / 2-D set to D-1, D-2, D-3). As in the first embodiment, the antenna element is divided into four antennas 2 and arranged in a quadrangular shape.

  FIG. 9 is an example of a selection logic table of the switches 3-1 to 3-4 according to the second embodiment. FIG. 10 shows an example of a switch system diagram. First, a case where rough search is performed will be described with reference to FIG. Since all four sets of array antennas 2 are used at the same time, the second antenna element at the center of each array antenna 2 and the switch 3 are connected. Here, for example, the direction A means a case where the array antenna 2-A set is searched for. In the rough search, no matter which set of array antennas 2 from 2-A to 2-D is searched for, the same antenna element is always connected. For example, the switch 3-1 is always connected to the antenna element A-2.

  Next, Fig. 9-2 shows a case where a refinement search is performed. The array antenna 2 that faces the direction of arrival of the radio wave calculated by the rough search is identified from the 2-A to 2-D sets, and the corresponding search is selected from the search A to the search D and the switch is selected. Switch between 3-1 to 3-4. In addition, what is shown in italics in the figure is a case where the same antenna element is used even when switching from rough search to fine search. For example, the switch 3-1 is connected to A-2 in the rough search, and is connected to the same A-2 even when switching to the fine search. From this figure, it is understood that, for example, the switch 3-1 is switched and connected to any one of the three antenna elements A-2, C-1, and D-3 and not switched to the other elements by the search case. Karu.

  Next, the operation will be described. An embodiment of a procedure for detecting the arrival direction of radio waves will be described. The flowchart is the same as FIG. 6 showing the first embodiment. First, for the coarse search, the approximate arrival direction is calculated in the same procedure as in the first embodiment, and one set of array antennas 2 is specified. Next, a rigorous search is carried out. The direction finding processor 5 selects the identified array antenna 2, switches the connection of the switch 3, and receives and receives incoming radio waves by the antenna elements 6 (three) of the array antenna 2. Specifically, as shown in FIG. 9-2, for example, when the array antenna 2-B set (search B) is selected, the switch 3-4 is switched to B-1 of the antenna element 6, and B-2 Switch 3-2 and switch B-3 corresponding to B-3 are switched correspondingly to select the array antenna 2-B set. This set of antenna elements 6 receives incoming radio waves.

  When the antenna element 6 receives a target incoming radio wave, the receiver 4 performs a Fourier transform on the radio wave and outputs a frequency signal. The direction finding processor 5 obtains the phase of the radio wave received by each antenna element 6 from the frequency signal output from the receiver 4, calculates the phase difference of each radio wave, and the object radiates from the phase difference. Performs a rigorous search to measure the detailed direction of arrival of radio waves.

Example 3 FIG.
FIG. 11 is a schematic diagram of an antenna according to Example 3 of the present invention. The antenna elements AB, BC, CD, and DA are attached to the four corners of the probe antenna 1 arranged in a square shape so that the directing direction is directed from the center of the square to the radiation direction. The number of antenna elements is reduced by using the antenna elements 6 of the two array antennas 2 adjacent to each other at one corner. Compared with the second embodiment, the total number of antenna elements 6 is reduced from 12 to 8, and space saving and cost reduction are possible.

  Next, the operation will be described. The signal processing flowchart is the same as that of the first embodiment. FIG. 12 shows an example of a switch selection logic table of the radio wave detector according to the third embodiment, and FIG. 13 shows an example of a switch system diagram. First, in rough search, the antenna elements 6AB, BC, CD, and DA arranged at the four corners are used to perform rough search for the entire covered area at the same time, and two sets of array antennas for performing the fine search are specified. . In FIG. 12A, the direction A means a case where the array antenna 2-A group is searched for. In the rough search, the switch 3 is always connected to the same antenna element 6 regardless of the fine search cases from the search A to the search D. For example, the switch 3-1 is always connected to the antenna element AB.

  Next, FIG. The switch 3 is switched to three antenna elements of the array antenna 2 that are most facing the radio wave arrival direction calculated as a result of the rough search (two are also used as the adjacent array antennas 2 arranged at the corners). For example, in the case of the direction C, the switch 3-1 is connected to the element C, the switch 3-2 is connected to the element BC, and the switch 3-3 is the element CD in order to search for a perfect way using the array antenna 2-C set. Are connected to each other. Therefore, for example, the switch 3-1 is only switched to two antenna elements AB and C as shown in FIGS. Therefore, the switch 3 is simplified because it switches to only two elements. When the switched antenna element 6 receives a radio wave radiated from the target, the receiver 4 performs a Fourier transform on the radio wave and outputs a frequency signal. The direction finding processor 5 calculates the phase difference of the radio wave received by each antenna element 6 from the frequency signal output from the receiver 4, and carries out a method for finding the detailed direction of arrival of the target radio wave from the phase difference. Do.

Example 4
FIG. 14 is a signal processing flowchart of the fourth embodiment. In the fourth embodiment, a plurality of sets including different antenna elements are sequentially selected with respect to an incoming radio wave transmitted from a radio wave source having a clear position in advance. For example, in the embodiment, the set (1) is antenna elements A-1, B-1, C-1, D-1 / set (2) is A-2, B-2, C-2, D-2 /. The set (3) includes A-3, B-3, C-3, D-3 / set (4), and includes A-4, B-4, C-4, and D-4. Each set is selected in turn by the switch 3, and each incoming radio wave is received.

  The receiver 4 detects the radio wave received by each antenna element 6, converts the signal into a video signal, and outputs the video signal. The directivity direction of the video signal corresponding to each antenna element 6 output from the receiver 4 is calculated by the direction finding processor 5 as the arrival direction of the radio wave. If the calculated result does not match the known direction, the corresponding antenna element 6 is identified as a defective product. If it matches the known orientation, the coarse search is performed for the next coarse search set. The above rough search is carried out for all four sets, and the inspection of all antenna elements 6 is completed.

1 is a schematic configuration diagram of a radio wave detector according to a first embodiment of the present invention. 1 is a schematic diagram of an antenna configuration of a radio wave detector according to Embodiment 1 of the present invention. 1 is a conceptual diagram of a method of searching for a radio wave detection device according to a first embodiment of the present invention; It is a switch selection logic table | surface of the radio wave detector by Example 1 of this invention. It is a switch system diagram of the radio wave detector according to the first embodiment of the present invention. It is a signal processing flowchart of the radio wave detector by Example 1 of this invention. It is a principle figure which calculates an arrival direction from the phase difference of the radio wave detector by Example 1 of the present invention. It is the antenna schematic of the radio wave detector by Example 2 of this invention. It is a switch selection logic table | surface of the radio wave detector by Example 2 of this invention. It is a switch system figure of the radio wave detector by Example 2 of the present invention. It is the antenna schematic of the radio wave detector by Example 3 of this invention. It is a switch selection logic table | surface of the radio wave detector by Example 3 of this invention. It is a switch system figure of the radio wave detector by Example 3 of the present invention. It is a signal processing flowchart of the radio wave detector by Example 4 of this invention.

Explanation of symbols

  1-way probe antenna, 2 array antenna, 3 switch, 4 receiver, 5-way probe processor, 6 antenna element, 7 antenna pattern.

Claims (4)

A plurality of sets of array antennas each having an antenna element arranged in an array for each of the small coverage areas obtained by dividing the entire circumference into a plurality of small coverage areas, and at least the same number as the number of sets of the array antennas. A plurality of switches for switching and connecting the signals received in the plurality, a plurality of receivers connected corresponding to the switches and measuring the amplitude, frequency and phase of the signals received by the antenna element, and the switches for switching Corresponding to the coarse search function that identifies the set of array antennas facing the signal arrival direction from the amplitude of the signal received by the antenna element selected for each set of array antennas connected to the receiver. And a precision search function for calculating the direction of arrival from the frequency and phase difference of the signals received by the antenna elements of the specified set of array antennas. Radiolocation apparatus being characterized in that a person probe processor has. 2. The radio wave detection apparatus according to claim 1, wherein the number of antenna elements arranged in an array on the array antenna is smaller than the number of sets of the array antennas. Four sets of array antennas are formed on each side of the square, and each set of array antennas is composed of two common antenna elements arranged at the apexes of the square and individual antenna elements arranged on the sides. The radio wave detection device according to claim 1, wherein Multiple sets of coarse search using different antenna elements of each array antenna are performed on incoming radio waves transmitted from a radio wave source at a known transmission position, and the signal arrival direction specified by the coarse search is most faced. 4. A function of identifying a failed antenna element by comparing a set of array antennas and a known transmission position of the radio wave transmission source. Radio wave detector.

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