JP4686265B2 - Radio monitoring device - Google Patents

Description

  The present invention relates to a radio wave monitoring apparatus that monitors radio waves emitted from a radio wave emission source.

  A radio wave monitoring device is a device that monitors illegal radio waves and the like, and detects, for example, the arrival direction, center frequency, bandwidth, and spurious intensity of radio waves emitted from a radio wave emission source. The detection result is displayed on the screen of the display.

When a conventional radio wave monitoring device detects the direction of arrival of radio waves, for example, it receives radio waves emitted from a radio wave emission source with multiple antennas, processes the received signals, detects the direction of arrival of radio waves, and estimates it. (See Patent Document 1).
JP-A-7-209358

  Conventional radio wave monitoring devices detect the arrival direction of radio waves and the quality of radio waves, such as the center frequency, bandwidth, and spurious intensity. However, since the effective radiation power of the radio wave emission source cannot be measured, there is a problem that it is impossible to monitor whether the output of the radio wave emitted from the radio wave emission source is illegal.

  An object of the present invention is to provide a radio wave monitoring apparatus that solves the above-described drawbacks and can measure the effective radiated power of radio waves emitted from a radio wave emission source.

The radio wave monitoring apparatus of the present invention has an array antenna and a reference antenna arranged in the vicinity of the array antenna, receives radio waves emitted from a radio wave emission source, and received by the radio wave reception means. Conversion means for digitizing a signal and converting it to reception data, and first calculation for obtaining a complex conjugate by Fourier-transforming reception data based on the reception signal of the reference antenna among the reception data converted by the conversion means Means, a second computing means for Fourier transforming the received data based on the received signal by each element of the array antenna among the received data converted by the converting means, a computation result of the first computing means, and the second Third calculation means for multiplying the calculation result of the calculation means by the frequency range of the radio wave emitted from the radio wave emission source, and the third calculation means The calculation results by the Fresnel approximation, the distance to the radio and the fourth computing means for obtaining a holographic image reproduced wave source, the radio wave source holographic reproduction image obtained in the fourth calculating means based on the coordinate having the largest And a radio wave attenuation amount calculating means for obtaining a radio wave attenuation amount based on the distance information obtained by the distance, and the radio wave attenuation value obtained by the radio wave attenuation amount calculating means. And an effective radiant power calculating means for obtaining an effective radiant power of the radio wave emission source based on the amount, the received power of the received signal, and the antenna gain of the radio wave receiving means.

  ADVANTAGE OF THE INVENTION According to this invention, the radio wave monitoring apparatus which can measure the information required for radio wave monitoring, for example, the effective radiant power of the radio wave emitted from the radio wave emission source, is realizable.

  An embodiment of the present invention will be described with reference to the circuit configuration diagram of FIG.

  The radio wave receiving unit 11 that receives radio waves emitted from the radio wave emission source T includes a reference antenna 11a and an array antenna 11b. The reference antenna 11a is formed from, for example, one reference antenna element 11R, and the array antenna 11b is formed from, for example, a plurality of N array antenna elements 111 to 11N. The reference antenna 11a and the array antenna 11b are arranged in the vicinity, and the N array antenna elements 111 to 11N are, for example, arranged in an array on a straight line at a certain interval, or provided at a certain interval in the vertical and horizontal directions, respectively. Arranged in a dimensional array.

  In FIG. 1, a reference antenna 11a and an array antenna 11b are provided separately. However, one of the array antenna elements 111 to 11N can be used as the reference antenna 11a.

  The received signal received by the reference antenna 11a is supplied to the frequency converter 12R. The array antenna elements 111 to 11N are connected to the switch SW. The reception signals received by the array antenna elements 111 to 11N are sequentially extracted one by one at a certain time interval, for example, by the operation of the switch SW, and supplied to the frequency conversion units 121 to 12N. The received signals supplied to the frequency conversion units 12R and 121 to 12N are frequency-converted by the local oscillation signal applied from the local oscillation unit 13 and sent to the AD conversion units 14R and 141 to 14N.

  The AD converters 14R and 141 to 14N digitize the received signals and convert them into received data. The reception data output from the AD conversion units 14R and 141 to 14N is sent to the signal processing unit 15.

  The signal processing unit 15 processes the received data, calculates the effective radiant power (hereinafter referred to as EIRP) of the radio wave emitted from the radio wave emission source, and sends the calculation result to the operation display input unit 16. The operation display input unit 16 displays the calculation result of the signal processing unit 15 on the screen and accepts input from the operator.

  For example, when a desired reception frequency band is input from the operator, the operation display input unit 16 sends the desired reception frequency band information to the signal processing unit 15. When the desired frequency band information is sent, the signal processing unit 15 sends the frequency setting signal C to the local oscillating unit 13 and the local oscillation generated by the local oscillating unit 13 so as to receive the signal of the desired receiving frequency band. Set the signal frequency.

  Here, the signal processing unit 15 will be described with reference to the circuit configuration diagram of FIG.

  The signal processing unit 15 includes a plurality of memories 21R and 211 to 21N. The memories 21R and 211 to 21N temporarily store the reception data transmitted from the AD conversion units 14R and 141 to 14N as reception data DR and D1 to DN, respectively.

  The reception data DR stored in the memory 21R is sent to the signal analysis unit 22. The signal analysis unit 22 processes the received data DR, for example, performs frequency analysis, and detects the radio wave quality such as the center frequency 23a, the band width 23b, the spurious intensity 23c, the received power 23d, and the like. These pieces of detection information are sent to the EIRP calculation processing unit 24. Note that the antenna gain data 25 of the radio wave receiving means 11 measured for each frequency and direction of the received radio wave is sent to the EIRP calculation processing unit 24 from an antenna gain table or the like.

  The received data DR and D1 to DN stored in the memories 21R and 211 to 21N are sent to the correlation matrix processing unit 26. The correlation matrix processing unit 26 obtains a correlation matrix based on the received data DR, D1 to DN, and sends the obtained correlation matrix to the two-dimensional FFT unit 27.

  The two-dimensional FFT unit 27 performs a two-dimensional FFT based on the correlation matrix obtained by the correlation matrix processing unit 26 and outputs a radio holographic image 28. The radio holographic image 28 is sent to the peak detection processing unit 29. The peak detection processing unit 29 performs peak detection from the output of the radio holographic image 28, specifies the position of the radio wave emission source T, calculates the distance to the radio wave emission source T, and the radio wave emission source T. A direction detection result 31 obtained by detecting the direction is output. The distance calculation result 30 and the direction detection result 31 are sent to the EIRP calculation processing unit 24, for example.

  The EIRP calculation processing unit 24 calculates the EIRP by the equation (1) based on the center frequency 23a and the reception power 23d sent from the signal analysis unit 22, the reception antenna gain 25a and the distance calculation result 30, and the radio wave emission EIRP of radio waves emitted from the source T is detected.

Pt = Pr-Gra + Lspan (1)
Pt: Effective radiation power (dBW) of radio wave emission source
Pr: Received power (dBW)
Gra: Receive antenna gain (dB): The antenna gain for each frequency and direction is measured in advance and stored in the antenna gain table.

Lspan: Attenuation (dB) due to the distance between the radio wave emission source and the reception point, and has the relationship of Equation (2).

Lspan = 20 log (4 × π × D / λ) (2)
D: distance between the radio wave emission source and the array antenna λ: wavelength of the center frequency And the EIRP of the radio wave emission source calculated by the above method and the center frequency, spurious intensity, bandwidth, etc. detected by the signal analysis unit 22 Each data is sent from the EIRP calculation processing unit 24 to, for example, the operation display input unit 16.

  As described above, when detecting the distance of the radio wave emission source and the direction of the radio wave emission source, the arithmetic processing is performed using the reception data DR and D1 to DN stored in the memories 21R and 211 to 21N. This calculation process is performed using parameters as shown in FIG. 3, for example. For example, the distance to the radio wave emission source T is z, and the axis orthogonal to the z axis connecting the radio wave reception unit 11 and the radio wave emission source T is the x axis. Further, the x coordinate of the reference antenna 11R is ξref, and the x coordinates of the N array antenna elements 111 to 11N are ξ1, ξ2,.

  Then, for example, the received data DR based on the received signal of the reference antenna 11 is Fourier transformed to obtain its complex conjugate. Also, the received data D1 to DN based on the received signals of the array antenna elements 111 to 11N are Fourier transformed. Then, the result of Fourier transform of the received data DR and the result of Fourier transform of the received data D1 to DN are multiplied by the frequency range of the radio wave emitted from the radio wave emission source T, and added, and the correlation matrix u ( ξn) is obtained. Further, the calculation result u (ξn) is substituted into an equation using Fresnel approximation to obtain a holographic reproduction image of the radio wave emission source. Thereafter, the position of the radio wave emission source T is specified from the coordinates at which the holographic reproduction image becomes maximum, and the distance of the radio wave emission source T and the direction of the radio wave emission source T are detected.

  Next, the operation of the present invention will be described with reference to the flowchart of FIG.

  First, a desired reception frequency band is set based on an input from the operation display input unit 16 (S401). Next, in order to receive a signal in the desired reception frequency band, each constant, for example, the frequency of the local oscillation signal of the local oscillator 13 is set (S402). Next, the incoming radio wave is received by the radio wave receiving means 11 (S403). Next, the received data digitized by AD conversion is accumulated (S404). Next, it is determined whether or not a necessary period, for example, a period for collecting data necessary for specifying the position of the radio wave emission source T is completed (S405).

  If it is determined in this determination that the accumulation of data for the necessary period has been completed, the frequency analysis unit 22 performs frequency analysis of the received signal based on the received data DR in the memory 21R (S406), and the center of the incoming radio wave The frequency 23a, bandwidth 23b, spurious intensity 23c, received power 23d, and the like are detected.

  Next, a correlation function is calculated based on each received data DR, D1 to DN, and a correlation matrix u (ξn) is created (S407). Next, two-dimensional FFT is performed (S408). Next, a ranging process for detecting the direction of the radio wave emission source T is performed (S410). After this distance measuring process (S410), S403 to S410 are repeated.

  If it is determined in S405 that the accumulation of data for the necessary period has not been completed, the process returns to S403.

  Here, FIG. 5 shows a screen example in which the measurement result is displayed on the operation display input unit 16. For example, the horizontal axis represents frequency (MHz), and the vertical axis represents level (dB).

  Then, the transmission waveform 51 obtained by calculation, the received reception waveform 52, and the like are shown on the screen. The specified value is displayed, for example, in a frame 53, and it is determined that, for example, the amplitude (EIRP) of the transmission waveform 51 extends outside the frame 53 and exceeds the specified value. A spurious 54 is displayed outside the frame 53. It is displayed that the center frequency 55 and the bandwidth are within the specified value range within the frame 53. In this case, items exceeding the specified value, for example, EIRP and spurious are surrounded by a frame 56 so that it can be identified whether or not the specified value is exceeded.

  In this way, if the calculation result of the signal processing unit 15 is displayed on the screen by the operation display input unit 16, it can be easily detected whether or not the transmission waveform exceeds the specified value.

  According to the present invention described above, it is possible to realize a radio wave monitoring apparatus that can detect information necessary for radio wave monitoring, for example, effective radiant power of radio waves emitted from a radio wave emission source. Therefore, it becomes easy for the operator to check whether the effective radiated power exceeds the specified value, and the operation efficiency is improved.

It is a circuit block diagram explaining embodiment of this invention. It is a circuit block diagram explaining the signal processing part which concerns on this invention. It is a figure for demonstrating the parameter used for specification of the position of the radio wave emission source which concerns on this invention. It is a flowchart for demonstrating operation | movement of this invention. It is a display screen figure explaining the example of a display of the operation display input part which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Radio wave reception part 11a ... Reference antenna 11b ... Array antenna 12R, 121-12N ... Frequency conversion part 13 ... Local oscillation part 14R, 141-14N ... AD conversion part 15 ... Signal processing part 16 ... Operation display input part 21R, 211 -21N ... Memory 22 ... Signal analysis unit 24 ... EIRP calculation processing unit 26 ... Correlation matrix processing unit 27 ... Two-dimensional FFT unit 28 ... Radio holographic image SW ... Switch

Claims (2)

An antenna having an array antenna and a reference antenna disposed in the vicinity of the array antenna, receiving a radio wave emitted from a radio wave emission source, and digitizing a reception signal received by the radio wave receiving means to receive data A conversion means for converting, a first calculation means for obtaining a complex conjugate of the received data based on the received signal of the reference antenna among the received data converted by the conversion means, and conversion by the conversion means Among the received data, the second computing means for Fourier transforming the received data based on the received signal by each element of the array antenna, the computing result of the first computing means and the computing result of the second computing means, Third calculation means for multiplying by the frequency range of the radio wave emitted from the radio wave emission source and adding the calculation result of the third calculation means to the Fresnel approximation Te, fifth operations and the fourth computing means for obtaining a holographic reproduction image of the radio wave source, holographic reproduction image obtained in the fourth calculating means detects a distance to the radio wave source based on the coordinate having the largest Means, a radio wave attenuation amount calculating means for determining a radio wave attenuation amount based on the distance information obtained by the fifth calculating means, and the radio wave attenuation amount and the received signal obtained by the radio wave attenuation amount calculating means. A radio wave monitoring apparatus comprising: an effective radiant power calculating means for obtaining an effective radiant power of the radio wave emission source based on received power and an antenna gain of the radio wave receiving means.   2. The radio wave monitoring apparatus according to claim 1, wherein the effective radiation power is obtained by Pt = Pr-Gra + Lspan, where Lspan is the radio wave attenuation, Pr is the received power, Gra is the antenna gain, and Pt is the effective radiation power.

Images