JP2007212228A - Electric wave emission source visualization device and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display an incoming direction estimation result by forming a two-dimensional image repeatedly at high speed, so that an electric wave emission source can be specified easily. <P>SOLUTION: Each electric wave received by a reference antenna A0 and an array antenna A1 is converted into a medium frequency, capable of AD conversion by a frequency conversion part 30. An antenna switching part 20 switches successively an antenna element output from the array antenna A1. Each electric wave, received by an element selected by the array antenna A1 and by the reference antenna A0, is digitized by an AD conversion part 40, and incoming direction estimation processing is performed by an incoming direction estimation processing part 50, and the result is converted into a two-dimensional image and displayed on a display part 60. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention estimates a radio wave arrival direction and easily specifies a radio wave emission source, and therefore, a radio wave emission source for outputting a two-dimensional arrival direction as a two-dimensional image such as an azimuth angle and an elevation angle of the arrival direction. The present invention relates to a visualization apparatus and a method thereof.

  Conventionally, in order to specify a radio wave emission source, a directional antenna, an electric field probe, and the like and a receiver are used to search for a site where the reception level is maximum, so to speak, the radio wave emission source is specified by hand search. Also, in recent years, the arrival direction of radio waves is estimated using an arrival direction estimation device using an array antenna and the like, and has been located close to the emission source. However, it is still extremely difficult to identify the part or place emitting radio waves.

Note that Patent Document 1 describes a method and apparatus for visualizing a wave source image by a radio holography method.
JP 09-134113 A

  As described above, in the conventional radio wave emission source visualization device and method, it is still extremely difficult to specify the portion or place where the radio wave is emitted.

  The present invention has been made to solve the above-described problem, and is a radio wave emission source visualization device capable of rapidly and repeatedly generating and displaying a direction of arrival estimation result so that the radio wave emission source can be easily identified. And providing a method thereof.

  In order to solve the above problems, a radio wave emission source visualization apparatus and method according to the present invention include a reference antenna that receives incoming radio waves in the same frequency band and an array antenna formed by arranging a plurality of antenna elements on a plane. The reception output of each element of the array antenna is sequentially switched from the antenna device provided to be derived simultaneously with the reception output of the reference antenna, and the arrival direction of radio waves from the simultaneous output of each element output of the array antenna and the reference antenna Is estimated by a radio holography method, and the direction of arrival estimation result obtained by two-dimensional imaging is displayed two-dimensionally.

  In the radio wave emission source visualization device and method according to the above configuration, the direction of arrival of radio waves from the radio wave source is estimated by radio holography, and two-dimensional images are displayed at high speed repeatedly. Can be easily identified.

  Therefore, according to the present invention, it is possible to provide a radio wave emission source visualization apparatus and method that can rapidly and repeatedly form and display the direction of arrival estimation result so that the radio wave emission source can be easily identified. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram schematically showing the configuration of a radio wave emission source visualization device according to an embodiment of the present invention. This apparatus includes an antenna unit 10, an antenna switching unit 20, a timing control unit 25, a frequency conversion unit 30, an AD conversion unit 40, an arrival direction estimation processing unit 50, and a display unit 60.

  The antenna unit 10 includes a reference antenna A0 and an array antenna A1. The reference antenna A0 and the array antenna A1 are receiving antennas that can measure the same frequency band. The array antenna A1 includes N antenna elements A11 to A1N arranged in a lattice pattern on a plane. The shape and type of the antenna elements, the total number of antenna elements, the interval for arranging the antenna elements, etc. are measured. It is optional depending on the measurement purpose. In order to suppress the sensitivity of radio waves incident from the opposite side of the array surface, the plane on which the antenna elements A11 to A1N are arranged can be used as a reflector.

  Any one of the antenna elements A11 to A1N can be used as the reference antenna A0. In this case, there is an advantage that a mechanical structure for separately attaching the reference antenna A0 becomes unnecessary.

  The antenna switching unit 20 switches the antenna elements to be sequentially received to the array antenna A1 based on the control signal from the timing control unit 25 at a predetermined order and interval, and the selected antenna element A1i (i is 1 to 1). N of N) received signals. As described above, one received signal among the selected array antennas A11 to A1N is sent to the frequency conversion unit 30 together with the received signal of the reference antenna A0, and is selected as the reference antenna A0 in the subsequent arrival direction estimation process. The phase difference between the received waves of the array antenna A1i can be detected.

  The frequency converter 30 amplifies the incoming radio wave and converts it to an intermediate frequency that can be AD-converted by the AD converter 40 at the subsequent stage. Based on the control signal from the timing control unit 25, the AD conversion unit 40 simultaneously samples and AD-converts the received signal from the antenna element A1i selected by the reference antenna A0 and the array antenna A1 and digitizes it. The data digitized by the AD conversion unit 40 is processed by the arrival direction estimation processing unit 50 and supplied to the display unit 60, and the arrival direction estimation result is converted into a two-dimensional image and displayed.

  FIG. 2 shows a processing flow of the arrival direction estimation processing unit 50 of the apparatus having the above configuration.

  In the arrival direction estimation processing unit 50, there are various types of processing. Here, processing by the radio holography method will be described. In this direction-of-arrival estimation process by the radio holography method, when the number of antenna elements of the array antenna A1 is N, N digital data of the reference antenna A0 and N digital data of the array antenna A1 are obtained. When the element number of the array antenna A1 is i = 1,..., N, the digital data of the reference antenna A0 and the digital data of the array antenna A1 are obtained for the element number i. Let digital data per element be M samples.

  In FIG. 2, in step ST11, the digital data of each antenna element A1i of the array antenna A1 is acquired together with the digital data of the reference antenna A0 by M samples from i = 1 to i = N according to the start direction estimation instruction.

  In step ST12, the digital data acquired in step ST11 is subjected to FFT (Fast Fourier Transform) processing to calculate a complex correlation value for a frequency range in which the direction of arrival is to be estimated.

  In step ST13, a correlation matrix is created from the complex correlation values obtained in step ST12. This correlation matrix is a mathematical matrix in which complex correlation values are arranged in the same arrangement as the physical arrangement of the array antenna A1.

  In step ST14, the periphery of the correlation matrix obtained in step ST13 is zero-filled to create an extended correlation matrix. This extended correlation matrix D is extended to, for example, a 256 × 256 matrix.

  In step ST15, two-dimensional FFT is performed on the extended correlation matrix obtained in step ST14, thereby calculating the arrival direction estimation result. As the arrival direction estimation result, the estimated radio wave intensity for each arrival direction is obtained. It is estimated that there is a radio wave emission source in the direction where the estimated radio wave intensity is strong.

  In the two-dimensional FFT, for example, a one-dimensional FFT is first performed for every row of the extended correlation matrix, and then a one-dimensional FFT is performed for every column. The arrival direction estimation result is obtained as a matrix, and the elements of each matrix correspond to the angles of arrival.

  The reason why the correlation matrix is the extended correlation matrix as described above is to intentionally increase the number of samples and improve the arrival direction estimation resolution when performing two-dimensional FFT.

  Upon receiving the arrival direction estimation result obtained by the arrival direction estimation processing unit 50, the display unit 60 colors the estimated radio wave intensity for each azimuth angle and elevation angle and displays it as a two-dimensional image. When the repetition of the measurement in steps ST11 to ST15 is selected in step ST16, a two-dimensional image at the time of each measurement is displayed in step ST15.

  As described above, in the direction-of-arrival estimation processing according to the present invention, since a two-dimensional FFT is used for two-dimensional visualization, processing is performed faster than other generally known MUSIC methods and interferometry methods. (The MUSIC method and the interferometry method require a scan at a fine angular interval when detecting the direction of arrival, and therefore require a large amount of calculation, and are not particularly suitable for two-dimensional visualization.) .

  Therefore, according to the above-described embodiment, the radio wave intensity for each direction of arrival is two-dimensionally imaged and displayed at high speed and repeatedly for the emitted radio wave, so that the radio wave emission source can be easily identified.

  The present invention can be applied in various fields such as a radio wave monitoring field for the purpose of finding a source of illegal radio waves such as an illegal mobile relay device, and a call where a mobile phone should be avoided. .

  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. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The block diagram which shows the structure of the radio wave emission source visualization apparatus of one Embodiment which concerns on this invention. The flowchart which shows the flow of a process of the arrival direction estimation process part shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Antenna part, A0 ... Reference antenna, A1 ... Array antenna, A11-A1N ... Antenna element, 20 ... Antenna switching part, 25 ... Timing control part, 30 ... Frequency conversion part, 40 ... AD conversion part, 50 ... Arrival direction Estimation processing unit, 60... Display unit.

Claims (3)

An antenna device including an array antenna formed by arranging a reference antenna that receives incoming radio waves in the same frequency band and a plurality of antenna elements on a plane;
Antenna switching means for sequentially switching and deriving the reception output of each element of the array antenna from the antenna device;
A direction-of-arrival estimation processing means for estimating a direction of arrival of a radio wave from the output of each element of the array antenna and the output of the reference antenna by a radio holography method, and outputting a direction-of-arrival estimation result obtained by two-dimensional imaging
A radio wave emission source visualizing device comprising: display means for displaying the arrival direction estimation result.   The radio wave emission source visualization device according to claim 1, wherein the reference antenna is a part of an antenna element of the array antenna. A process of sequentially switching and deriving the reception output of each element of the array antenna from an antenna device including an array antenna in which a reference antenna that receives incoming radio waves in the same frequency band and a plurality of antenna elements are arranged on a plane;
A process of estimating the arrival direction of radio waves from the output of each element of the array antenna and the output of the reference antenna by a radio holography method, and outputting a result obtained by two-dimensional imaging,
A radio wave emission source visualization method comprising: displaying the estimation result of the direction of arrival.

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