JP5955140B2 - Angle measuring device and angle measuring method - Google Patents

Description

  The present invention relates to an angle measuring device and an angle measuring method for measuring an arrival direction of a radio wave radiated from a radio wave radiation source by implementing a super resolution method such as MUSIC or ESPRIT.

The receiver installed in the angle measuring device amplifies the received signal of the element antenna using a low noise amplifier, and converts the frequency of the received signal to an intermediate frequency using a down converter. After performing high-frequency signal processing (front-end processing) such as using a filter to suppress unwanted frequency band signals contained in the received signal, the received signal is digitally converted using an A / D converter. Perform processing to convert to signal.
Therefore, in the recent complicated and overcrowded use of radio waves, the operation of the receiver becomes complicated and highly functional, and the cost of the receiver occupying the entire angle measuring device increases.

On the other hand, let us improve the accuracy and performance of angle measuring devices that receive radio waves radiated from the target radio wave radiation source and measure the direction of arrival of radio waves in the increasingly complex and crowded radio wave conditions in recent years. Then, it is necessary to increase the number of element antennas and increase the aperture area as an array antenna.
In addition, when the frequency bands of radio waves emitted from multiple radio wave radiation sources are the same, and multiple radio waves interfere with each other and enter the angle measuring device, the multiple radio waves are separated and the direction of arrival of each radio wave A separate angle measurement function is required to measure the angle.

In general, if the number of element antennas constituting the array antenna is “M”, the number of incoming radio waves that can be separated and measured is up to “M−1”. The value “M−1” is referred to as the degree of freedom of the angle measuring device.
Therefore, an increase in the number of element antennas is unavoidable in improving the separation angle measurement performance.

In an ordinary angle measuring device, there is a one-to-one correspondence between element antennas and receivers. For the reasons described above, when the number of element antennas increases, the number of necessary receivers also increases. Increases in cost, large-scale equipment, and increase in power consumption are problems.
In Patent Document 1 below, there is a method of reducing only the number of receivers without reducing the number of element antennas, focusing on the structure of the covariance matrix used in the super-resolution method in order to deal with the above problem. It is disclosed.

即ち、特許文献１に開示されている測角装置では、５個の素子アンテナと、２台の受信機とを実装し、受信素子選択部が、５個の素子アンテナの中から、２個の素子アンテナを時分割で選択して、２台の受信機にそれぞれ接続することで、共分散行列の各要素を順次取得する方法を採用している。 In the method disclosed in Patent Document 1, each element of the covariance matrix used in the super-resolution method is obtained by using one of the reception signals of two element antennas as shown in the following equation (1). A structure of multiplying the other received signal as a complex conjugate is adopted.

That is, in the angle measuring device disclosed in Patent Document 1, five element antennas and two receivers are mounted, and the receiving element selection unit includes two element antennas out of the five element antennas. A method is adopted in which each element of the covariance matrix is sequentially acquired by selecting element antennas in time division and connecting them to two receivers.

  The covariance matrix R ′ constructed as described above is acquired by a normal angle measuring device in which the element antenna and the receiver are in a one-to-one correspondence under the condition satisfying the above equation (1). Therefore, even if the number of receivers is only two, the performance equivalent to that of the angle measuring device that simultaneously acquires the reception signals of the five element antennas, that is, the degree of freedom is 4 The performance that the angle can be separated and measured up to (= 5-1) radio waves can be obtained.

Here, it is assumed that a total of K radio waves are incident on the angle measuring device. However, K <M.
s _j (t _qn ) is the signal (radio wave) of the kth incident wave at time t _qn , and s _l (t _qn ) is the signal (radio wave) of the lth incident wave at time t _qn , where 1 ≦ j, l ≦ K and ≠ l.
Q at time t _qn is the n-th time of the q-th observation period, and when the number of element antennas is 5 (M = 5), n is a numerical value from 1 to 15 and the value of n The relationship between the two element antennas selected for the output port and the output port is defined, and the observation is repeated Q times (1 ≦ q ≦ Q) with n = 1 to 15 as one observation period. ing.
E [] is a symbol indicating that a time average is calculated.

Therefore, the above equation (1) means that the correlation coefficient between any two radio waves in the total number of K radio waves can be regarded as time-invariant (constant at any time). can do.
As a radio wave modulation method satisfying the equation (1), for example, FM (Frequency Modulation), PSK (Phase Shift Keying), OFDM (Orthogonal Frequency Division Multiple Access), SS (Spectrum S, etc.) A modulation scheme based on phase modulation is applicable.
As a radio wave modulation method that does not satisfy the equation (1), for example, a modulation method based on amplitude modulation basically corresponds to AM (Amplitude Modulation) and QAM (Quadrature Amplitude Modulation).

FIG. 12 is a configuration diagram showing the angle measuring device disclosed in Patent Document 1. In FIG.
FIG. 13 is an explanatory diagram showing a result of angle measurement when the angle measuring device disclosed in Patent Document 1 separates and measures two waves by the MUSIC method.
In FIG. 13, the horizontal axis represents the arrival angle of radio waves, the vertical axis represents the MUSIC spectrum, and standardization is performed so that the maximum value is 0 dB.
The algorithm is such that an arrival angle having a high spectrum (close to 0 dB) is estimated as an arrival angle of the radio wave.

The MUSIC method is applied to a covariance matrix R ′ constructed by receiving and observing an incident wave in which two independent Gaussian noise-like signals are mixed as a signal satisfying the above equation (1). .
In FIG. 13, there are a plurality of lines because a total of 10 independent trials are performed and the results are overlapped, and the fluctuation factor of each trial is assumed to be noise of the receiver. Yes.
Since this incident wave satisfies the above equation (1), as shown in FIG. 13, the peak of the spectrum is drawn approximately in the vicinity of the true value arrival angle of two waves. For this reason, even if the number of receivers is only two, which is smaller than the number of element antennas, the angle measurement results obtained by applying the MUSIC method to the covariance matrix R acquired by a normal angle measuring device are almost the same. Has gained performance.

FIG. 14 is an explanatory diagram showing time-axis waveforms of two AM modulated signals that do not satisfy Expression (1).
When two AM modulated signals that do not satisfy Expression (1) are generated and the two AM modulated signals are mixed, a time axis plot of the interference waveform as shown in FIG. 15 is drawn.
When the MUSIC method is applied to a covariance matrix R ′ constructed by making an incident wave mixed with two AM modulation signals incident on an angle measuring device disclosed in Patent Document 1, the angle measurement is performed. The result is as shown in FIG.
Also in FIG. 16, a total of 10 independent trials are performed, and the results are drawn in an overlapping manner.
Compared with FIG. 13 which is the angle measurement result when the condition of Expression (1) is satisfied, it can be seen that FIG. 16 has a large error with respect to the true value of the arrival angle and a large angle measurement error. .

JP 2008-241457 (paragraph number [0015], FIG. 1)

  Since the conventional angle measuring device is configured as described above, when the modulation method of the radio wave emitted from the radio wave radiation source is an amplitude modulation method that does not satisfy Equation (1) (for example, modulation based on amplitude modulation). In the case of a system), there is a problem that a measurement result in which the MUSIC method is applied to a covariance matrix R ′ constructed by receiving and observing the radio wave has a very large angle measurement error.

  The present invention has been made to solve the above-described problems, and is an angle measuring device that can accurately measure the direction of arrival of radio waves regardless of the modulation method of radio waves radiated from a radio wave radiation source. And it aims at obtaining the angle measuring method.

The angle measuring device according to the present invention includes a plurality of receiving antennas that receive radio waves radiated from a radio wave radiation source, and a radio wave that selects an arbitrary received signal from among the received signals of the radio waves received by the plurality of receiving antennas. The number of selection means and the number of receiving antennas less than the number of receiving antennas are prepared, and output from a plurality of receivers that output the reception signals of the radio waves selected by the radio wave selection means, and specific receivers among the plurality of receivers. the amplitude of the received signal, and an amplitude normalizing means for normalizing the amplitude of the received signals output from a plurality of receivers, using the received signal output from the amplitude normalizing means, it radiated from radio source and the arrival direction estimation means for estimating the direction of arrival of radio waves, modulation scheme estimating means for estimating a radio wave modulation mode emitted from the radio source based on the received signals output from a plurality of receivers, a plurality of Based on the received signal output from the transmitter, calculated by the cross-correlation coefficient calculation means and the cross-correlation coefficient calculation means for calculating the cross-correlation coefficient at each time between radio waves emitted from a plurality of radio wave radiation sources The cross-correlation coefficient storage means for storing the cross-correlation coefficient at each time and the cross-correlation coefficients at each time stored in the cross-correlation coefficient storage means are arranged in time series so that the cross-correlation coefficient Fluctuation determining means for determining whether or not there is a fluctuation with the lapse of time, and the amplitude normalization means determines whether or not the modulation scheme estimated by the modulation scheme estimation means is a specific modulation scheme, or determines variation When it is determined that the cross-correlation coefficient fluctuates with time, the amplitude of the received signal output from a specific receiver among the multiple receivers is output from the multiple receivers. Standardized received signal amplitude Then, the standardized received signal is output to the arrival direction estimating means, and the modulation method estimated by the modulation method estimating means is not a specific modulation method, but the cross-correlation coefficient is changed with time by the fluctuation determining means. Output signal is output to the arrival direction estimation means without normalizing the amplitude of the reception signals output from the plurality of receivers, the arrival direction estimation means is the amplitude normalization means The arrival direction of the radio wave radiated from the radio wave radiation source is estimated using the reception signal output from the radio wave.

According to the present invention, even if the modulation method of the incident wave incident on the angle measuring device changes from moment to moment, the optimum operation according to the modulation method can be quickly adopted, and the higher The angle measurement result of the direction of arrival of radio waves can be obtained with high accuracy.

It is a block diagram which shows the angle measuring device by Embodiment 1 of this invention. It is a flowchart which shows the processing content of the angle measuring device by Embodiment 1 of this invention. It is explanatory drawing which shows the angle measurement result when the angle measuring apparatus of FIG. 1 carries out separate angle measurement of the incident wave mixed with 2 waves of AM modulation signals by the MUSIC method. It is a block diagram which shows the angle measuring device by Embodiment 2 of this invention. It is a block diagram which shows the angle measuring device by Embodiment 3 of this invention. It is a block diagram which shows the angle measuring device by Embodiment 4 of this invention. It is a block diagram which shows the angle measuring device by Embodiment 5 of this invention. It is a block diagram which shows the angle measuring device by Embodiment 6 of this invention. It is explanatory drawing which shows the fluctuation | variation of the correlation coefficient with respect to the interference waveform of two independent AM modulation signals. It is a block diagram which shows the angle measuring device by Embodiment 7 of this invention. It is a block diagram which shows the angle measuring device by Embodiment 8 of this invention. It is a block diagram which shows the angle measuring device currently disclosed by patent document 1. FIG. It is explanatory drawing which shows the angle measurement result when the angle measuring apparatus currently disclosed by patent document 1 carries out the separate angle measurement of 2 waves by the MUSIC method. It is explanatory drawing which shows the time-axis waveform of two independent AM modulation signals. It is explanatory drawing which shows the time-axis waveform in which the 2 wave AM modulation signal of FIG. 14 was mixed. It is explanatory drawing which shows the angle measurement result when the angle measuring apparatus currently disclosed by patent document 1 carries out the separate angle measurement of the incident wave with which 2 waves of AM modulation signals were mixed by the MUSIC method.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an angle measuring device according to Embodiment 1 of the present invention.
In FIG. 1, element antennas 1-1 to 1-M are receiving antennas that receive incident signals (radio waves) radiated from a plurality of radio wave radiation sources.
Although FIG. 1 shows an example in which two-wave incident signals s ₁ (t _qn ) and s ₂ (t _qn ) are incident, the total number of element antennas 1-1 to 1-M is M. , (M-1) waves can be measured separately.
Here, it is assumed that two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) are AM modulated waves in the same frequency band as shown in FIG. 14, and two AM modulations as shown in FIG. It is assumed that a wave interference signal is incident on the element antennas 1-1 to 1-M.

The receiving element selection unit 2 includes, for example, a changeover switch. Under the control of the signal processing unit 5, an arbitrary received signal r _i (t _{qn) is selected} from the received signals of the element antennas 1-1 to 1-M. ), R _k (t _qn ), the received signal r _i (t _qn ) is output to the receiver 3-1, and the received signal r _k (t _qn ) is output to the receiver 3-2. Perform the process. The receiving element selection unit 2 constitutes a radio wave selection unit.

The receivers 3-1 to 3-2 are prepared in a smaller number than the element antennas 1-1 to 1 -M (two are prepared in the example of FIG. 1), and are output from the receiving element selection unit 2. The received signal r _i (t _qn ), r _k (t _qn ) is received, and the digital received signal x _i (t _qn ), x _k (t _qn ) is output to the amplitude standard section 4. carry out.
That is, the receivers 3-1 to 3-2 amplify the received signals r _i (t _qn ) and r _k (t _qn ) output from the receiving element selection unit 2 using a low noise amplifier (Low Noise Amplifier). and, using a down-converter, the received signal r _i (t _qn), converts the frequency of r _k (t _qn) to an intermediate frequency, using a filter, the received signal _{r i (t qn), r} k Processing for converting a received signal into a digital signal using an A / D converter after performing high-frequency signal processing (front-end processing) such as suppressing unnecessary frequency band signals included in (t _qn ) And so on.

The amplitude standard unit 4 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted, or a one-chip microcomputer, and the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1. Processing for normalizing the amplitudes of the digital reception signals x _i (t _qn ) and x _k (t _qn ) output from the receivers 3-1 to 3-2 is performed.
Here, the digital reception signal x _i (t _qn ), x _k output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1. Although the amplitude of (t _qn ) is standardized, the digital reception output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _k (t _qn ) output from the receiver 3-2. The amplitudes of the signals x _i (t _qn ) and x _k (t _qn ) may be normalized.
The amplitude standard unit 4 constitutes an amplitude normalization means.

The signal processing unit 5 includes a timing control unit 6, a covariance matrix generation unit 7, and a separated angle measurement processing unit 8, and the digital reception signal x _i (t _qn ), the amplitude of which is normalized by the amplitude standardization unit 4. Using x _k (t _qn ), a process for estimating the arrival directions of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source is performed.
That is, the signal processing unit 5 constructs a covariance matrix R ″ using the digital reception signals x _i (t _qn ) and x _k (t _qn ) whose amplitudes are normalized by the amplitude standard unit 4, and the covariance matrix By applying the MUSIC method to R ″, the process of separating and measuring the arrival directions of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source is performed. .
The signal processing unit 5 constitutes an arrival direction estimating unit.

The timing control unit 6 of the signal processing unit 5 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted or a one-chip microcomputer. The switching timing of the element antenna 1 with respect to the receiving element selection unit 2 and the covariance matrix A process for controlling the generation timing of R ″ and the like is performed.
The covariance matrix generation unit 7 of the signal processing unit 5 generates a covariance matrix R ″ using the digital reception signals x _i (t _qn ) and x _k (t _qn ) whose amplitudes are normalized by the amplitude standard unit 4. Perform the process.
The separation angle measurement processing unit 8 of the signal processing unit 5 applies the MUSIC method to the covariance matrix R ″ generated by the covariance matrix generation unit 7, so that the incident signal of two waves radiated from the radio wave radiation source is obtained. A process of separately measuring the arrival directions of s ₁ (t _qn ) and s ₂ (t _qn ) is performed.

In the example of FIG. 1, the element antennas 1-1 to 1-M, the receiving element selection unit 2, the receivers 3-1 to 3-2, the amplitude standard unit 4 and the signal processing unit 5 which are components of the angle measuring device. Each of them is composed of dedicated hardware, but all or part of the angle measuring device may be composed of a computer.
For example, when a part of the angle measuring device (components excluding the element antennas 1-1 to 1-M) is configured by a computer, the receiving element selection unit 2, the receivers 3-1 to 3-2, the amplitude standard A program describing the processing contents of the unit 4 and the signal processing unit 5 may be stored in the memory of a computer, and the CPU of the computer may execute the program stored in the memory.
FIG. 2 is a flowchart showing the processing contents of the angle measuring device according to Embodiment 1 of the present invention.

Next, the operation will be described.
In the first embodiment, incident signals s ₁ (t _qn ) and s ₂ (t _qn ) radiated from two radio wave radiation sources are mixed and incident on M element antennas 1-1 to 1-M. Shall be.
Here, q of t _qn is the n-th time of the q-th observation cycle. For example, when the number of element antennas is 5 (M = 5), n is a numerical value from 1 to 15, and The relationship between the two element antennas selected for the value of n and the output port is defined, and repeated observations are performed Q times (1 ≦ q ≦ Q) with n = 1 to 15 as one observation period. Represents what to do.

The timing control unit 6 of the signal processing unit 5 outputs a selection signal c (t) indicating the element antenna 1 to be selected from the reception signals of the element antennas 1-1 to 1-M (step ST1 in FIG. 2). ).
Note that the element antennas 1 to be selected indicated by the selection signal c (t) output from the timing control unit 6 are sequentially switched in a time division manner, and the switching timing and the element antennas 1 to be selected are set in advance. It is assumed that it is determined with reference to a correspondence table (not shown) (a table showing a correspondence relationship between switching timings and element antennas to be selected). As the correspondence table, for example, the correspondence table disclosed in FIG.

Upon receiving the selection signal c (t) from the timing control unit 6 of the signal processing unit 5, the reception element selection unit 2 selects the selection signal c (t) from among the M element antennas 1-1 to 1-M. Is selected, and the reception signals r _i (t _qn ) and r _k (t _qn ) of the element antenna 1 are received by the receiver 3-1. Output to 3-2 (step ST2).
In the example of FIG. 1, the received signal r _i (t _qn ) is output to the receiver 3-1, and the received signal r _k (t _qn ) is output to the receiver 3-2.

When the reception signals r _i (t _qn ) and r _k (t _qn ) are output from the reception element selection unit 2, the receivers 3-1 to 3-2 receive the reception signals r _i (t _qn ) and r _k. The reception processing of (t _qn ) is performed, and the digital reception signals x _i (t _qn ) and x _k (t _qn ) are output to the amplitude standard unit 4 (step ST3).
That is, when the reception signals r _i (t _qn ) and r _k (t _qn ) are output from the reception element selection unit 2, the receivers 3-1 to 3-2 use the low noise amplifier to receive the reception signals. r _i (t _qn ), r _k (t _qn ) are amplified, and the frequency of the amplified received signals r _i (t _qn ), r _k (t _qn ) is converted to an intermediate frequency using a down converter.
Further, the receivers 3-1 to 3-2 perform processing to suppress unnecessary frequency band signals included in the intermediate frequency received signals r _i (t _qn ) and r _k (t _qn ) using a filter. carry out.
Then, the receivers 3-1 to 3-2 convert the received signals r _i (t _qn ) and r _k (t _qn ) after the suppression processing into digital signals using an A / D converter, The received signals x _i (t _qn ) and x _k (t _qn ) are output to the amplitude standard unit 4.

When receiving the digital reception signals x _i (t _qn ) and x _k (t _qn ) from the receiver 3-1, the amplitude standard unit 4 receives the digital reception signals x _i ( the amplitude of the t _qn), output from the receiver 3-1～3-2 digital received signal x _i (t _qn), to normalize the amplitude of x _k (t _qn) (step ST4).

Here, the digital reception signal x _i (t _qn ), x _k output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1. Although the amplitude of (t _qn ) is standardized, the digital reception output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _k (t _qn ) output from the receiver 3-2. The amplitudes of the signals x _i (t _qn ) and x _k (t _qn ) may be normalized.
The normalization processing by the amplitude standard unit 4 is performed for all n in the observation period q.

When the signal processing unit 5 receives the digital received signals x _i (t _qn ) and x _k (t _qn ) standardized from the amplitude standard unit 4, the signal processing unit 5 receives the digital received signals x _i (t _qn ) and x _k (t _qn ) is used to estimate the direction of arrival of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source.
Hereinafter, the processing content of the signal processing unit 5 will be specifically described.

When receiving the standardized digital reception signals x _i (t _qn ) and x _k (t _qn ) from the amplitude standardization unit 4, the covariance matrix generation unit 7 of the signal processing unit 5 receives the digital reception signals x _i (t _qn ), x _k (t _qn ) is used to generate a covariance matrix R ″ (step ST5).
Note that all elements of the covariance matrix R "is the amplitude of the digital reception signal x _i (t _qn), is amplitude digital reception signal x _i that is standardized _{(t qn), x k (} t qn) .
Since the covariance matrix R ″ generation process itself is a known technique, a detailed description thereof will be omitted.

When the covariance matrix generation unit 7 generates the covariance matrix R ″, the separation angle measurement processing unit 8 of the signal processing unit 5 applies the MUSIC method to the covariance matrix R ″ from the radio wave radiation source. The arrival directions of the radiated two-wave incident signals s ₁ (t _qn ) and s ₂ (t _qn ) are separated and measured (step ST6).
Note that the MUSIC method is applied to the covariance matrix R ″ to separate and measure the arrival directions of the incident signals s ₁ (t _qn ) and s ₂ (t _qn ), which is a known technique. The detailed explanation is omitted.

Here, FIG. 3 is an explanatory view showing a result of angle measurement when the angle measuring device of FIG. 1 separates and measures an incident wave mixed with two AM modulated signals by the MUSIC method.
Also in FIG. 3, a total of 10 independent trials are performed, and the results are overlaid.
As is clear from comparison between the measurement results of FIG. 3 and FIG. 16 (angle measurement result of the conventional angle measuring device), in FIG. 16, the AM modulation signal is violently disturbed and has a large angle measurement error. In the angle measurement result of FIG. 3 by the angle measuring device of the first embodiment, a stable result is obtained for the AM modulation signal, and the vicinity of the true value of the arrival angle is accurately represented.

In the conventional angle measuring device disclosed in Patent Document 1, when the radio wave modulation method is a phase modulation method, the above equation (1) is satisfied, but when the radio wave modulation method is an amplitude modulation method, Since the above equation (1) is not satisfied, the AM modulation signal is violently disturbed and has a large angle measurement error.
This is because the angle measuring device handled in this technical field is based on the principle of the “phase difference angle measuring method” in which the angle is measured using the relative phase difference between each element antenna of the radio wave incident on the array antenna. .
However, in the first embodiment, the amplitude of the received signal of the two element antennas is normalized by the amplitude of one of the received signals of the two element antennas, so that the amplitude fluctuation component is canceled. Thus, only the component of the relative phase difference can be left. For this reason, the function as the original “phase difference angle measuring device” can be recovered.
Note that this method is not limited to the case where the incident signal is two waves, and it is possible to separate and measure angles up to an incident signal of (M-1 wave) or less which is the original degree of freedom of the array antenna. This naturally includes single wave incidence.

As apparent from the above, according to the first embodiment, the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1 is output from the receivers 3-1 to 3-2. An amplitude standard unit 4 that normalizes the amplitudes of the digital received signals x _i (t _qn ) and x _k (t _qn ) is provided, and the signal processing unit 5 is a digital received signal whose amplitude is standardized by the amplitude standard unit 4. Since x _i (t _qn ) and x _k (t _qn ) are used to estimate the direction of arrival of the radio wave emitted from the radio wave radiation source, it is related to the modulation method of the radio wave emitted from the radio wave radiation source. In addition, it is possible to measure the direction of arrival of radio waves with high accuracy.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing an angle measuring device according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG.
The modulation scheme estimation unit 9 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted, a one-chip microcomputer, or the like, and the digital reception signal x _i (t _qn) output from the receivers 3-1 to 3-2. ), X _k (t _qn ) is performed to estimate the modulation method of the radio wave emitted from the radio wave radiation source. The modulation scheme estimation unit 9 constitutes a modulation scheme estimation means.

In the example of FIG. 4, the element antennas 1-1 to 1-M, the reception element selection unit 2, the receivers 3-1 to 3-2, the amplitude standard unit 4, the signal processing unit 5 and the component elements of the angle measuring device Although each of the modulation scheme estimation units 9 is configured by dedicated hardware, all or part of the angle measuring device may be configured by a computer.
For example, when a part of the angle measuring device (components excluding the element antennas 1-1 to 1-M) is configured by a computer, the receiving element selection unit 2, the receivers 3-1 to 3-2, the amplitude standard If the program describing the processing contents of the unit 4, the signal processing unit 5 and the modulation scheme estimation unit 9 is stored in the memory of a computer, and the CPU of the computer executes the program stored in the memory Good.

Next, the operation will be described.
However, since it is the same as that of Embodiment 1 except that the modulation scheme estimation unit 9 is mounted, only the processing contents of the modulation scheme estimation unit 9 will be described here.
Upon receiving the digital reception signals x _i (t _qn ) and x _k (t _qn ) from the receivers 3-1 to 3-2, the modulation scheme estimation unit 9 receives the digital reception signals x _i (t _qn ) and x _k. Based on (t _qn ), the modulation method of the radio wave radiated from the radio wave radiation source is estimated.

However, the modulation method estimation unit 9 may specifically estimate the radio wave modulation method, but the modulation method of the radio wave radiated from the radio wave radiation source satisfies the above equation (1). It may be estimated to the extent that it is determined whether the user is satisfied or not satisfied.
In this determination, for example, it is investigated whether or not the amplitude of the digital reception signals x _i (t _qn ) and x _k (t _qn ) varies with time, and if the amplitude does not vary with time. (It does not fluctuate more than a predetermined value), it is determined that the above equation (1) is satisfied, and if the amplitude fluctuates with time (fluctuates more than a predetermined value), the above equation ( It can be determined that 1) is not satisfied.
Note that the estimation result of the modulation scheme estimation unit 9 is stored in a memory (not shown).

As apparent from the above, according to the second embodiment, the modulation scheme estimation unit 9 receives the digital received signals x _i (t _qn ), x _k (t Since the configuration is such that the modulation method of the radio wave radiated from the radio wave radiation source is estimated based on _qn ), there is an effect that it is possible to determine whether or not the amplitude standardization process by the amplitude standardization unit 4 is necessary.

Embodiment 3 FIG.
FIG. 5 is a block diagram showing an angle measuring device according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG.
For example, the standardization control unit 10 includes a semiconductor integrated circuit on which a CPU is mounted, a one-chip microcomputer, or the like, and the modulation method estimated by the modulation method estimation unit 9 is a specific modulation method (formula (If (1) is not satisfied), a control signal indicating that the digital received signals x _i (t _qn ) and x _k (t _qn ) are normalized is output to the amplitude standard unit 11, and the modulation scheme estimation unit When the modulation method estimated by 9 is not a specific modulation method (when the expression (1) is satisfied), the digital reception signals x _i (t _qn ) and x _k (t _qn ) are not normalized. The process which outputs the control signal which shows this to the amplitude specification part 11 is implemented.

For example, the amplitude standard unit 11 includes a semiconductor integrated circuit on which a CPU is mounted, a one-chip microcomputer, or the like, and the control signal output from the standardization control unit 10 indicates that standardization is to be performed. In the same manner as the amplitude standard unit 4 in FIG. 1, the digital reception signal output from the receivers 3-1 to 3-2 with the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1. The amplitudes of x _i (t _qn ) and x _k (t _qn ) are normalized, and the standardized digital received signals x _i (t _qn ) and x _k (t _qn ) are output to the signal processing unit 5 and standardized. Digital control signal x _i (t _qn ), x _k (t) output from the receivers 3-1 to 3-2 when the control signal output from the control unit 10 indicates that normalization is not performed. the amplitude of _qn) without normalization, the digital reception signal _{x i (t qn), x} k ( and it carries out a process of outputting _qn) to the signal processing unit 5.
The normalization control unit 10 and the amplitude normalization unit 11 constitute amplitude normalization means.

In the example of FIG. 5, the element antennas 1-1 to 1-M, the receiving element selection unit 2, the receivers 3-1 to 3-2, the modulation scheme estimation unit 9, and the normalization control unit, which are components of the angle measuring device. 10, the amplitude standard unit 11 and the signal processing unit 5 are each configured by dedicated hardware, but all or part of the angle measuring device may be configured by a computer.
For example, when a part of the angle measuring device (components excluding the element antennas 1-1 to 1-M) is configured by a computer, the receiving element selection unit 2, the receivers 3-1 to 3-2, the modulation method A program describing the processing contents of the estimation unit 9, the normalization control unit 10, the amplitude standard unit 11, and the signal processing unit 5 is stored in the memory of a computer, and the program stored in the memory by the CPU of the computer is stored. It should be executed.

Next, the operation will be described.
The modulation scheme estimation unit 9 radiates radio waves based on the digital reception signals x _i (t _qn ) and x _k (t _qn ) output from the receivers 3-1 to 3-2, as in the second embodiment. Estimate the modulation method of radio waves emitted from the source.

When the modulation scheme estimated by the modulation scheme estimator 9 is a modulation scheme based on amplitude modulation such as AM modulation, for example, the standardization controller 10 receives digital reception when the expression (1) is not satisfied. A control signal indicating that the signals x _i (t _qn ) and x _k (t _qn ) are normalized is output to the amplitude standard unit 11.
On the other hand, when the modulation scheme estimated by the modulation scheme estimation unit 9 is a modulation scheme based on phase modulation such as FM modulation, for example, when the expression (1) is satisfied, the digital received signal x _i (t _qn ), x _k (t _qn ) is output to the amplitude standard unit 11 as a control signal indicating that normalization is not performed.

When the control signal output from the standardization control unit 10 indicates that the standardization is performed, the amplitude standardization unit 11 is the same as the amplitude standardization unit 4 in FIG. the amplitude of the received signal x _i (t _qn), output from the receiver 3-1～3-2 digital received signal x _i (t _qn), normalized amplitude of x _k (t _qn), normalized The subsequent digital received signals x _i (t _qn ) and x _k (t _qn ) are output to the signal processing unit 5.
Here, the digital reception signal x _i (t _qn ), x _k output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1. Although the amplitude of (t _qn ) is standardized, the digital reception output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _k (t _qn ) output from the receiver 3-2. The amplitudes of the signals x _i (t _qn ) and x _k (t _qn ) may be normalized.

When the control signal output from the standardization control unit 10 indicates that the standardization control unit 10 does not perform standardization, the amplitude standardization unit 11 outputs the digital reception signal x _i (t) output from the receivers 3-1 to 3-2. _qn), the amplitude of x _k (t _qn) without normalization, and outputs the digital received signal _{x i (t qn), x} k a (t _qn) to the signal processing unit 5.

The signal processing unit 5, a digital received signal from the amplitude standard unit 11 x _i (t _qn), receives the x _k (t _qn), as in the first embodiment, the digital reception signal x _i (t _qn) , X _k (t _qn ), the arrival directions of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source are estimated.
However, in the digital reception signals x _i (t _qn ) and x _k (t _qn ) output from the amplitude standard unit 11, the modulation scheme estimated by the modulation scheme estimation unit 9 does not satisfy Expression (1). In the case of satisfying the formula (1), it is not standardized.
If the expression (1) is satisfied, the incident signal s ₁ (t _qn ) can be accurately obtained even if the _{unstandardized} digital reception signals x _i (t _qn ) and x _k (t _qn ) are used. ), S ₂ (t _qn ) can be estimated.

As is apparent from the above, according to the third embodiment, when the modulation scheme estimated by the modulation scheme estimation unit 9 is a specific modulation scheme (when Expression (1) is not satisfied), digital reception A control signal indicating that the signals x _i (t _qn ) and x _k (t _qn ) are normalized is output to the amplitude standard unit 11, and the modulation scheme estimated by the modulation scheme estimation unit 9 is not a specific modulation scheme. In this case (when the expression (1) is satisfied), a standard for outputting to the amplitude standard unit 11 a control signal indicating that the digital received signals x _i (t _qn ) and x _k (t _qn ) are not normalized If the control unit 10 is provided and the amplitude standard unit 11 indicates that the control signal output from the standardization control unit 10 performs normalization, the digital received signal x _i output from the receiver 3-1 is used. with an amplitude of (t _qn), digital output from the receiver 3-1～3-2 Le received signal x _i (t _qn), normalized amplitude of x _k (t _qn), the digital reception signal x _i (t _qn) after normalization, x _k (t _qn) output to the signal processing unit 5 When the control signal output from the standardization control unit 10 indicates that the standardization is not performed, the digital reception signals x _i (t _qn ), x output from the receivers 3-1 to 3-2. without normalizing amplitude of _k (t _qn), the digital reception signal x _i (t _qn), and then, is output x _k a (t _qn) to the signal processing unit 5, the radio modulation scheme It is possible to adopt an optimum operation according to the response, and there is an effect that a highly accurate angle measurement result can be obtained.

In the third embodiment, when the modulation scheme estimated by the modulation scheme estimation unit 9 is not a specific modulation scheme (when Expression (1) is satisfied), the normalization control unit 10 Although the control signal indicating that the normalization of x _i (t _qn ) and x _k (t _qn ) is not performed is output to the amplitude standard unit 11, the modulation scheme estimated by the modulation scheme estimation unit 9 is Regardless of whether or not a specific modulation system is used (regardless of whether or not the expression (1) is satisfied), the normalization control unit 10 receives the digital received signals x _i (t _qn ), x _k (t A control signal indicating that the normalization of _qn ) is to be performed may be output to the amplitude standard unit 11.
In this case, the amplitude standardization unit 11 always standardizes the digital reception signals x _i (t _qn ) and x _k (t _qn ), and the signal processing unit 5 always performs the standardized digital reception signal x. _{Using i} (t _qn ) and x _k (t _qn ), the arrival directions of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source are estimated. .

Therefore, even when the modulation scheme estimated by the modulation scheme estimator 9 is not a specific modulation scheme (when Expression (1) is satisfied), the standardized digital reception signals x _i (t _qn ), x _k (T _qn ) is used to estimate the direction of arrival of incident signals s ₁ (t _qn ) and s ₂ (t _qn ), but the modulation scheme is based on phase modulation that satisfies equation (1). However, since the amplitude normalization processing by the above equation (2) operates effectively (the modulation method of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) radiated from the radio wave radiation source is the phase). Since the correlation coefficient (details will be described later) between the incident signals of the two waves in the case of the modulation method does not change over time as shown in FIG. 9, the amplitude normalization processing according to equation (2) operates effectively) of digital received signals x _i (t _qn), even with x _k (t _qn), incidence of two-wave No. _{s 1 (t qn), s} 2 the direction of arrival of (t _qn) can be accurately estimated.

Embodiment 4 FIG.
6 is a block diagram showing an angle measuring device according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG.
The correlation coefficient estimator 12 is composed of, for example, a semiconductor integrated circuit in which a CPU is mounted, a one-chip microcomputer, or the like, and the digital reception signal x _i (t (t) output from the receivers 3-1 to 3-2. _qn ), x _k (t _qn ) processing for calculating a cross-correlation coefficient at each time between incident signals s ₁ (t _qn ) and s ₂ (t _qn ) radiated from a plurality of radio wave radiation sources To implement. The correlation coefficient estimator 12 constitutes a cross correlation coefficient calculation means.

In the example of FIG. 6, the element antennas 1-1 to 1-M, the receiving element selection unit 2, the receivers 3-1 to 3-2, the amplitude standard unit 4, the signal processing unit 5 and the component elements of the angle measuring device Although each of the correlation coefficient estimation units 12 is configured by dedicated hardware, all or part of the angle measuring device may be configured by a computer.
For example, when a part of the angle measuring device (components excluding the element antennas 1-1 to 1-M) is configured by a computer, the receiving element selection unit 2, the receivers 3-1 to 3-2, the amplitude standard The program describing the processing contents of the unit 4, the signal processing unit 5 and the correlation coefficient estimating unit 12 is stored in the memory of the computer, and the CPU of the computer is executed by the program stored in the memory. That's fine.

Next, the operation will be described.
However, since it is the same as that of the first embodiment except that the correlation coefficient estimation unit 12 is implemented, the processing content of the correlation coefficient estimation unit 12 will be mainly described here.
When the correlation coefficient estimation unit 12 receives the digital reception signals x _i (t _qn ) and x _k (t _qn ) from the receivers 3-1 to 3-2, the digital reception signals x _i (t _qn ) and x _{Based on k} (t _qn ), a cross-correlation coefficient at each time between incident signals s ₁ (t _qn ) and s ₂ (t _qn ) radiated from a plurality of radio wave radiation sources is calculated.

Specifically, the correlation coefficient estimator 12 uses the equation (3) which is the left side of the above equation (1), that is, the correlation between two arbitrary waves when a plurality of radio waves are incident on the angle measuring device. The number is estimated.
Usually, arbitrary two waves s _j (t _qn ) and s _k (t _qn ) are unknown, and further, since they interfere with each other and enter the angle measuring device, the angle measuring device must separate these two waves. I can't. Therefore, it is difficult for the angle measuring device to directly calculate Equation (3) from the received signal of the receiver 3.

Therefore, the correlation coefficient estimation unit 12 estimates the correlation coefficient of two waves by the estimation method as described below.
When incident signals s ₁ (t _qn ) and s ₂ (t _qn ) radiated from a plurality of radio wave radiation sources are received, digital received signals x _i (t _qn ) are received from the receivers 3-1 to 3-2. , X _k (t _qn ) are output.
At this time, the (i, k) element of the covariance matrix R ″ generated by the covariance matrix generation unit 7 of the signal processing unit 5 is expressed by the following expression (4). However, the expression (4) Then, the thermal noise generated in the receiver 3 is ignored.

式（４）において、ａ_i（θ₁）は第１入射波である入射信号ｓ₁（ｔ_qn）の到来角度θ₁に対する第ｉ素子アンテナの複素アンテナゲインを示している。

In Expression (4), a _i (θ ₁ ) represents the complex antenna gain of the i-th element antenna with respect to the arrival angle θ ₁ of the incident signal s ₁ (t _qn ) that is the first incident wave.

Correlation coefficient E [s ₁ (t _qn ) s ₂ ^* (t _qn ) of incident signals s ₁ (t _qn ) and s ₂ (t _qn ) which are two incident waves incorporated in the formula (4) ] Is time-invariant as indicated by the above formula (1).
On the other hand, assuming that the radio wave radiation source (1) and the radio wave radiation source (2) are both stationary and the relative angles θ ₁ and θ ₂ from the angle measuring device are constant, the radio waves coming from the respective radio wave radiation sources. Since the complex antenna gains a _i (θ ₁ ) and a _k (θ ₂ ) with respect to the arrival angles of the _two are also constant scalar values, the correlation coefficient E [s ₁ (t _qn ) s ₂ ^* (t _qn )] Is a constant multiple of the correlation coefficient E [x ₁ (t _qn ) x ₂ ^* (t _qn )] of the digital received signals x _i (t _qn ), x _k (t _qn ). Works.
That is, from the correlation coefficient E [x ₁ (t _qn ) x ₂ ^* (t _qn )] of the digital reception signals x _i (t _qn ) and x _k (t _qn ), the correlation coefficient E [ s ₁ (t _qn ) s ₂ ^* (t _qn )] can be estimated with a certain bias. However, it is not necessary to obtain this bias itself.

As is apparent from the above, according to the fourth embodiment, the correlation coefficient estimator 12 receives the digital received signals x _i (t _qn ), x _k (x _k ) output from the receivers 3-1 to 3-2. based on t _qn), the incident signal emitted from a plurality of radio source s ₁ (t _qn), since it is configured to calculate the s ₂ (t _qn) correlation coefficient at each time between unknown It is possible to grasp the trend of the correlation coefficient E [s ₁ (t _qn ) s ₂ ^* (t _qn )] of the two incident waves.

Embodiment 5 FIG.
7 is a block diagram showing an angle measuring device according to Embodiment 5 of the present invention. In the figure, the same reference numerals as those in FIG.
The correlation coefficient storage unit 13 is composed of a storage device such as a RAM or a hard disk, for example, and stores the cross-correlation coefficient at each time calculated by the correlation coefficient estimation unit 12. The correlation coefficient storage unit 13 constitutes a cross correlation coefficient storage unit.

Next, the operation will be described.
Correlation coefficient estimator 12 estimates the trend of the correlation coefficient between incident waves during each observation time n within one observation period, as in the fourth embodiment, and provides estimation results for all observation times n. The result is output to the correlation coefficient storage unit 13.
The correlation coefficient storage unit 13 stores the correlation coefficient between incident waves, which is an estimation result of the correlation coefficient estimation unit 12 for each observation time n, so that each observation time n within one observation cycle in which n completes a cycle. The correlation coefficient estimation result for is stored.
Thereby, it becomes possible to grasp the fluctuation on the time axis within one observation period of the correlation coefficient between a plurality of incident signals incident on the angle measuring device.

Embodiment 6 FIG.
FIG. 8 is a block diagram showing an angle measuring device according to Embodiment 6 of the present invention. In the figure, the same reference numerals as those in FIG.
The correlation coefficient time variation estimation unit 14 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted or a one-chip microcomputer, and the cross correlation coefficient at each time stored in the correlation coefficient storage unit 13. Are arranged in time series, and a process of determining whether or not the cross-correlation coefficient varies with the passage of time is performed. Note that the correlation coefficient fluctuation estimating unit 14 constitutes a fluctuation determining means.

In the example of FIG. 8, the element antennas 1-1 to 1-M, the receiving element selection unit 2, the receivers 3-1 to 3-2, the amplitude standard unit 4, the signal processing unit 5, which are components of the angle measuring device, Although the correlation coefficient estimation unit 12, the correlation coefficient storage unit 13, and the correlation coefficient time variation estimation unit 14 are each configured by dedicated hardware, all or part of the angle measuring device is a computer. It may be comprised.
For example, when a part of the angle measuring device (components excluding the element antennas 1-1 to 1-M) is configured by a computer, the correlation coefficient storage unit 13 is configured on the memory of the computer and the receiving element A program describing the processing contents of the selection unit 2, the receivers 3-1 to 3-2, the amplitude standard unit 4, the signal processing unit 5, the correlation coefficient estimation unit 12, and the correlation coefficient time variation estimation unit 14 The CPU of the computer may execute the program stored in the memory.

Next, the operation will be described.
Similar to the fifth embodiment, the correlation coefficient storage unit 13 is an incident result that is an estimation result of the correlation coefficient estimation unit 12 for each observation time n observed by switching any two elements from the element antenna 1 to time division. By storing the correlation coefficient between waves, the correlation coefficient estimation results for each observation time n within one observation period in which n makes a round are held in time series.

The correlation coefficient fluctuation estimator 14 tracks the fluctuation of the estimation result at each observation time n within one observation period held in the correlation coefficient storage unit 13 on the time axis, so that the estimation result is It is determined whether or not it varies with the passage of time (determines whether or not the condition of the above formula (1) is satisfied).
That is, it is estimated whether the correlation coefficient between a plurality of incident waves currently incident on the angle measuring device is a time-invariant state or a time-variable state, and the correlation coefficient as shown in FIG. Plot the variation over time.
FIG. 9 is a plot of correlation coefficient fluctuations with respect to the interference waveform of two independent AM modulation signals (see FIG. 15). The minimum and maximum values on the horizontal axis correspond to the time of one observation period. .

In the example of FIG. 9, when the correlation coefficient between two AM modulation signals for each observation time n varies with time, the condition of the above equation (1) is not satisfied.
As a result, it is possible to determine whether or not the correlation coefficient between the plurality of incident waves currently incident on the angle measuring device satisfies the condition of Expression (1). Therefore, it is possible to determine whether or not the normalization process by the amplitude standard unit 4 is necessary.

Embodiment 7 FIG.
10 is a block diagram showing an angle measuring device according to Embodiment 7 of the present invention. In the figure, the same reference numerals as those in FIG.
The standardization control unit 15 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted or a one-chip microcomputer, and the cross-correlation coefficient varies with the passage of time by the correlation coefficient time variation estimation unit 14. If it is determined that the digital received signals x _i (t _qn ) and x _k (t _qn ) are to be normalized, an amplitude standard is set. When the correlation coefficient time variation estimation unit 14 determines that the cross correlation coefficient does not vary with time (when the expression (1) is satisfied), the digital reception is performed. A process of outputting a control signal indicating that the signals x _i (t _qn ) and x _k (t _qn ) are not normalized to the amplitude standard unit 16 is performed.

The amplitude standard unit 16 is composed of, for example, a semiconductor integrated circuit mounted with a CPU or a one-chip microcomputer, and the control signal output from the standardization control unit 15 indicates that standardization is to be performed. In the same manner as the amplitude standard unit 4 in FIG. 1, the digital reception signal output from the receivers 3-1 to 3-2 with the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1. The amplitudes of x _i (t _qn ) and x _k (t _qn ) are normalized, and the standardized digital received signals x _i (t _qn ) and x _k (t _qn ) are output to the signal processing unit 5 and standardized. Digital control signals x _i (t _qn ), x _k (t) output from the receivers 3-1 to 3-2 when the control signal output from the control unit 15 indicates that normalization is not performed. the amplitude of _qn) without normalization, the digital reception signal _{x i (t qn), x} k ( and it carries out a process of outputting _qn) to the signal processing unit 5.
The normalization control unit 15 and the amplitude standard unit 16 constitute amplitude normalization means.

In the example of FIG. 10, the element antennas 1-1 to 1-M, the receiving element selection unit 2, the receivers 3-1 to 3-2, the correlation coefficient estimation unit 12, and the correlation coefficient, which are components of the angle measuring device. The storage unit 13, the correlation coefficient time variation estimation unit 14, the normalization control unit 15, the amplitude standard unit 16, and the signal processing unit 5 are each configured by dedicated hardware. All or a part may be constituted by a computer.
For example, when a part of the angle measuring device (components excluding the element antennas 1-1 to 1-M) is configured by a computer, the correlation coefficient storage unit 13 is configured on the memory of the computer and the receiving element Describes processing contents of the selection unit 2, the receivers 3-1 to 3-2, the correlation coefficient estimation unit 12, the correlation coefficient time variation estimation unit 14, the normalization control unit 15, the amplitude standard unit 16, and the signal processing unit 5. The stored program may be stored in the memory of the computer, and the CPU of the computer may execute the program stored in the memory.

Next, the operation will be described.
Similar to the sixth embodiment, the correlation coefficient time variation estimation unit 14 arranges the cross-correlation coefficients at each time stored in the correlation coefficient storage unit 13 in time series, and the cross-correlation coefficient is the time. It is determined whether or not it has fluctuated as time passes.

If the determination result of the correlation coefficient fluctuation estimation unit 14 indicates that the cross-correlation coefficient varies with the passage of time, the normalization control unit 15 satisfies Expression (1). _Therefore , a control signal indicating that the digital reception signals x _i (t _qn ) and x _k (t _qn ) are normalized is output to the amplitude standard unit 16.
On the other hand, if the determination result of the correlation coefficient fluctuation estimator 14 indicates that the cross-correlation coefficient does not vary with the passage of time, the digital reception is satisfied because Expression (1) is satisfied. A control signal indicating that the signals x _i (t _qn ) and x _k (t _qn ) are not normalized is output to the amplitude standard unit 16.

When the control signal output from the normalization control unit 15 indicates that the normalization is to be performed, the amplitude standard unit 16 performs the digital output from the receiver 3-1 in the same manner as the amplitude standard unit 4 in FIG. the amplitude of the received signal x _i (t _qn), output from the receiver 3-1～3-2 digital received signal x _i (t _qn), normalized amplitude of x _k (t _qn), normalized The subsequent digital received signals x _i (t _qn ) and x _k (t _qn ) are output to the signal processing unit 5.
When the amplitude standard unit 16 receives the control signal from the normalization control unit 15, the amplitude standardization process shown in Expression (2) is executed after each observation time n = 1 in the next observation cycle q + 1. .
Here, the digital reception signal x _i (t _qn ), x _k output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1. Although the amplitude of (t _qn ) is standardized, the digital reception output from the receivers 3-1 to 3-2 is the amplitude of the digital reception signal x _k (t _qn ) output from the receiver 3-2. The amplitudes of the signals x _i (t _qn ) and x _k (t _qn ) may be normalized.

When the control signal output from the standardization control unit 15 indicates that the standardization control unit 15 does not perform standardization, the amplitude standardization unit 16 outputs the digital reception signal x _i (t) output from the receivers 3-1 to 3-2. _qn), the amplitude of x _k (t _qn) without normalization, and outputs the digital received signal _{x i (t qn), x} k a (t _qn) to the signal processing unit 5.

The signal processing unit 5, a digital received signal from the amplitude standard unit 16 x _i (t _qn), receives the x _k (t _qn), as in the first embodiment, the digital reception signal x _i (t _qn) , X _k (t _qn ), the arrival directions of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source are estimated.
However, the digital reception signals x _i (t _qn ) and x _k (t _qn ) output from the amplitude standard unit 16 indicate that the cross-correlation coefficient varies with time, and the modulation scheme is Standardization is performed only when Expression (1) is not satisfied, and when Expression (1) is satisfied, it is not standardized.
If the expression (1) is satisfied, the incident signal s ₁ (t _qn ) can be accurately obtained even if the _{unstandardized} digital reception signals x _i (t _qn ) and x _k (t _qn ) are used. ), S ₂ (t _qn ) can be estimated.

As is apparent from the above, according to the seventh embodiment, when the correlation coefficient fluctuation estimation unit 14 determines that the cross-correlation coefficient varies with time (formula (1)) The control signal indicating that the digital received signals x _i (t _qn ) and x _k (t _qn ) are to be normalized is output to the amplitude standard unit 16, and the correlation coefficient time variation estimation unit is output. 14, when it is determined that the cross-correlation coefficient does not vary with time (when the expression (1) is satisfied), the digital reception signals x _i (t _qn ), x _k (t _qn ) Is provided with a standardization control unit 15 that outputs a control signal indicating that the standardization is not performed to the amplitude standardization unit 16, and the amplitude standardization unit 16 standardizes the control signal output from the standardization control unit 15 If showing the fact, digital received signal output from the receiver 3-1 x _i (t _qn In the amplitude output from the receiver 3-1～3-2 digital received signal x _i (t _qn), normalized amplitude of x _k (t _qn), the digital reception signal after normalization x _i ( When t _qn ), x _k (t _qn ) are output to the signal processing unit 5 and the control signal output from the normalization control unit 15 indicates that the standardization is not performed, the receivers 3-1 to 3-3 output -2 digital received signal x _i (t _qn), the amplitude of x _k (t _qn) without normalization, the digital reception signal _{x i (t qn), x} k (t qn) signal Since it is configured to output to the processing unit 5, it is possible to adopt an optimum operation according to the radio wave modulation method, and there is an effect that a more accurate angle measurement result can be obtained.

In the seventh embodiment, if the determination result of the correlation coefficient fluctuation estimation unit 14 indicates that the cross-correlation coefficient does not vary with time, Expression (1) is satisfied. Therefore, the control signal indicating that the digital received signals x _i (t _qn ) and x _k (t _qn ) are not normalized is output to the amplitude standard unit 16. Regardless of whether or not the cross-correlation coefficient is determined to have changed over time by the fluctuation estimation unit 14 (regardless of whether or not the expression (1) is satisfied), the normalization control unit 15 may output a control signal indicating that the digital reception signals x _i (t _qn ) and x _k (t _qn ) are normalized to the amplitude standard unit 16.
In this case, the amplitude standard unit 16 always standardizes the digital reception signals x _i (t _qn ) and x _k (t _qn ), and the signal processing unit 5 always performs the standardized digital reception signal x. _{Using i} (t _qn ) and x _k (t _qn ), the arrival directions of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source are estimated. .

Therefore, even when the determination result of the correlation coefficient fluctuation estimator 14 indicates that the cross-correlation coefficient does not vary with time (when the expression (1) is satisfied), The arrival directions of the incident signals s ₁ (t _qn ) and s ₂ (t _qn ) are estimated using the standardized digital received signals x _i (t _qn ) and x _k (t _qn ). This is because the amplitude normalization processing according to the above equation (2) operates effectively even when the modulation method is based on phase modulation that satisfies the equation (1).
The correlation coefficient between the two wave incident signals when the modulation method of the two wave incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source is the phase modulation method is shown in FIG. Thus, the amplitude normalization process according to the equation (2) operates effectively.
For this reason, even if the standardized digital received signals x _i (t _qn ) and x _k (t _qn ) are used, the arrival directions of the two-wave incident signals s ₁ (t _qn ) and s ₂ (t _qn ) are determined. It can be estimated accurately.

Embodiment 8 FIG.
FIG. 11 is a block diagram showing an angle measuring device according to Embodiment 8 of the present invention. In the figure, the same reference numerals as those in FIGS.
For example, the amplitude standard unit 17 includes a semiconductor integrated circuit on which a CPU is mounted or a one-chip microcomputer, and the control signal output from the standardization control unit 10 indicates that standardization is to be performed. Alternatively, when the control signal output from the normalization control unit 15 indicates that normalization is to be performed, the digital reception signal x output from the receiver 3-1 is similar to the amplitude standard unit 4 in FIG. with an amplitude of _i (t _qn), output from the receiver 3-1～3-2 digital received signal x _i (t _qn), normalized amplitude of x _k (t _qn), digital after normalization When the received signals x _i (t _qn ) and x _k (t _qn ) are output to the signal processing unit 5 and the control signals output from the normalization control units 10 and 15 indicate that normalization is not performed, Digital received signal x _i output from receivers 3-1 to 3-2 (T _qn), without normalizing the amplitude of x _k (t _qn), the digital reception signal x _i (t _qn), carries out a process of outputting x _k a (t _qn) to the signal processing unit 5. The amplitude standard unit 17 constitutes an amplitude normalization means.

In the example of FIG. 11, the element antennas 1-1 to 1-M, the receiving element selection unit 2, the receivers 3-1 to 3-2, the modulation scheme estimation unit 9, and the normalization control unit, which are components of the angle measuring device. 10, each of the correlation coefficient estimation unit 12, the correlation coefficient storage unit 13, the correlation coefficient time variation estimation unit 14, the normalization control unit 15, the amplitude standardization unit 17, and the signal processing unit 5 is configured by dedicated hardware. However, all or part of the angle measuring device may be configured by a computer.
For example, when a part of the angle measuring device (components excluding the element antennas 1-1 to 1-M) is configured by a computer, the correlation coefficient storage unit 13 is configured on the memory of the computer and the receiving element Selection unit 2, receivers 3-1 to 3-2, modulation scheme estimation unit 9, normalization control unit 10, correlation coefficient estimation unit 12, correlation coefficient time variation estimation unit 14, normalization control unit 15, amplitude standard The program describing the processing contents of the unit 17 and the signal processing unit 5 may be stored in the memory of a computer, and the CPU of the computer may execute the program stored in the memory.

Next, the operation will be described.
Since the modulation scheme estimated by the modulation scheme estimator 9 is a modulation scheme based on amplitude modulation such as AM modulation, as in the third embodiment, the normalization control unit 10 uses equation (1). Is not satisfied, a control signal indicating that the digital received signals x _i (t _qn ) and x _k (t _qn ) are normalized is output to the amplitude standard unit 17.
On the other hand, when the modulation scheme estimated by the modulation scheme estimation unit 9 is a modulation scheme based on phase modulation such as FM modulation, for example, when the expression (1) is satisfied, the digital received signal x _i (t _qn ), x _k (t _qn ) is output to the amplitude standard unit 17 as a control signal indicating that normalization is not performed.

As in the case of the seventh embodiment, the normalization control unit 15 determines that the determination result of the correlation coefficient time variation estimation unit 14 indicates that the cross-correlation coefficient varies with time. Since the expression (1) is not satisfied, a control signal indicating that the digital received signals x _i (t _qn ) and x _k (t _qn ) are normalized is output to the amplitude standard unit 17.
On the other hand, if the determination result of the correlation coefficient fluctuation estimator 14 indicates that the cross-correlation coefficient does not vary with the passage of time, the digital reception is satisfied because Expression (1) is satisfied. A control signal indicating that the signals x _i (t _qn ) and x _k (t _qn ) are not normalized is output to the amplitude standard unit 17.

The amplitude standard unit 17 indicates that the control signal output from the standardization control unit 10 indicates that normalization is performed, or the control signal output from the standardization control unit 15 indicates that normalization is performed. 1, the amplitude of the digital reception signal x _i (t _qn ) output from the receiver 3-1 is output from the receivers 3-1 to 3-2 in the same manner as the amplitude standard unit 4 in FIG. 1. The amplitudes of the digital reception signals x _i (t _qn ) and x _k (t _qn ) are normalized, and the standardized digital reception signals x _i (t _qn ) and x _k (t _qn ) are output to the signal processing unit 5. To do.
On the other hand, when the control signals output from the normalization control units 10 and 15 indicate that normalization is not performed, the digital reception signals x _i (t _qn ) output from the receivers 3-1 to 3-2. , X _k (t _qn ) without normalizing the amplitudes, the digital received signals x _i (t _qn ), x _k (t _qn ) are output to the signal processing unit 5.

Here, when the control signal output from the normalization control unit 10 indicates that normalization is performed, or when the control signal output from the normalization control unit 15 indicates that normalization is performed , The control signal indicating that the digital reception signals x _i (t _qn ) and x _k (t _qn ) are normalized is output to the amplitude standard unit 17. When the output control signal indicates that normalization is to be performed, a control signal indicating that the digital reception signals x _i (t _qn ) and x _k (t _qn ) are to be normalized is _sent to the amplitude standard unit 17. You may make it output.
In this case, the control signal output from the standardization control unit 10 indicates that the standardization is not performed, or the control signal output from the standardization control unit 15 indicates that the standardization is not performed. If there are, it outputted from the receiver 3-1～3-2 digital received signal x _i (t _qn), the amplitude of x _k (t _qn) without normalization, the digital reception signal x _i (t _qn ), X _k (t _qn ) are output to the signal processor 5.

The signal processing unit 5, a digital received signal from the amplitude standard unit 16 x _i (t _qn), receives the x _k (t _qn), as in the first embodiment, the digital reception signal x _i (t _qn) , X _k (t _qn ), the arrival directions of the _two incident signals s ₁ (t _qn ) and s ₂ (t _qn ) emitted from the radio wave radiation source are estimated.

According to the eighth embodiment, the independent standardization control unit 10 and the standardization control unit 15 simultaneously receive the digital reception signals x _i (t _qn ) and x _k (t _qn ) from the amplitude standardization unit 17. ) Is controlled, even if the modulation method of the incident wave incident on the angle measuring device changes from moment to moment, the optimum operation according to the modulation method can be adopted quickly. Thus, there is an effect that a more accurate angle measurement result can be obtained.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1-1 to 1-M element antenna (receiving antenna), 2 receiving element selection unit (radio wave selection means), 3-1 to 3-2 receiver, 4 amplitude standardization unit (amplitude standardization unit), 5 signal processing unit (Arrival direction estimation means), 6 timing control section, 7 covariance matrix generation section, 8 separate angle measurement processing section, 9 modulation system estimation section (modulation system estimation means), 10 normalization control section (amplitude normalization means), DESCRIPTION OF SYMBOLS 11 Amplitude standardization part (amplitude normalization means), 12 Correlation coefficient estimation part (cross-correlation coefficient calculation means), 13 Correlation coefficient storage part (cross-correlation coefficient storage means), 14 Correlation coefficient time variation estimation part ( Fluctuation determination means), 15 normalization control section (amplitude normalization means), 16 amplitude standardization section (amplitude normalization means), 17 amplitude standardization section (amplitude normalization means).

Claims (3)

A plurality of receiving antennas for receiving radio waves radiated from a radio wave radiation source;
Radio wave selection means for selecting an arbitrary received signal from radio wave received signals received by the plurality of receiving antennas;
A plurality of receivers that are prepared for a number smaller than the number of the reception antennas and that output a reception signal of the radio wave selected by the radio wave selection means,
Amplitude normalization means for normalizing the amplitude of the reception signal output from the plurality of receivers with the amplitude of the reception signal output from a specific receiver among the plurality of receivers;
Using the received signal output from the amplitude normalization means, the arrival direction estimation means for estimating the arrival direction of the radio wave radiated from the radio wave radiation source ;
A modulation scheme estimation means for estimating a modulation scheme of radio waves radiated from the radio wave radiation source based on reception signals output from the plurality of receivers;
Cross-correlation coefficient calculating means for calculating a cross-correlation coefficient at each time between radio waves radiated from the plurality of radio wave radiation sources based on reception signals output from the plurality of receivers;
Cross-correlation coefficient storage means for storing the cross-correlation coefficient at each time calculated by the cross-correlation coefficient calculation means;
Fluctuation determining means for arranging the cross-correlation coefficients at each time stored in the cross-correlation coefficient storage means in a time series and determining whether or not the cross-correlation coefficient varies with the passage of time; Prepared,
In the amplitude normalization means, when the modulation scheme estimated by the modulation scheme estimation means is a specific modulation scheme, or when the cross-correlation coefficient fluctuates over time by the fluctuation determination means If determined, the amplitude of the reception signal output from the plurality of receivers is normalized by the amplitude of the reception signal output from a specific receiver among the plurality of receivers, and the reception after normalization is performed. The signal is output to the direction-of-arrival estimation means, and the modulation method estimated by the modulation method estimation means is not a specific modulation method, and the cross-correlation coefficient does not change over time by the fluctuation determination means. If it is determined, the angle measuring device outputs the received signal to the arrival direction estimating means without normalizing the amplitude of the received signal output from the plurality of receivers . 2. The angle measuring device according to claim 1, wherein the arrival direction estimating means separately measures the arrival directions of radio waves radiated from a plurality of radio wave radiation sources. When radio wave radiated from the radio source is received by a plurality of receiving antennas, radio selection radio selection means from among the radio waves received signals received by the plurality of receiving antennas, to select any of the received signal Processing steps;
A plurality of receivers less than the number of the receiving antennas, a reception processing step for outputting a reception signal of the radio wave selected in the radio wave selection processing step;
Amplitude normalization processing step in which the amplitude normalization means normalizes the amplitude of the reception signal output from the plurality of receivers with the amplitude of the reception signal output from the specific receiver among the plurality of receivers. When,
An arrival direction estimation means for estimating an arrival direction of a radio wave radiated from the radio wave radiation source using the reception signal output from the amplitude normalization processing step ;
A modulation method estimation processing step for estimating a modulation method of radio waves radiated from the radio wave radiation source based on reception signals output from the plurality of receivers;
A cross-correlation coefficient for calculating a cross-correlation coefficient at each time between radio waves radiated from the plurality of radio wave radiation sources, based on reception signals output from the plurality of receivers. An arithmetic processing step;
A cross-correlation coefficient storage means for storing a cross-correlation coefficient at each time calculated by the cross-correlation coefficient calculation means;
The fluctuation determining means arranges the cross-correlation coefficients at each time stored in the cross-correlation coefficient storage means in a time series, and determines whether or not the cross-correlation coefficient fluctuates with the passage of time. Fluctuation determination processing step,
In the amplitude normalization means, when the modulation scheme estimated by the modulation scheme estimation means is a specific modulation scheme, or when the cross-correlation coefficient fluctuates over time by the fluctuation determination means If determined, the amplitude of the reception signal output from the plurality of receivers is normalized by the amplitude of the reception signal output from a specific receiver among the plurality of receivers, and the reception after normalization is performed. The signal is output to the direction-of-arrival estimation means, and the modulation method estimated by the modulation method estimation means is not a specific modulation method, and the cross-correlation coefficient does not change over time by the fluctuation determination means. If it is determined, the angle measuring method is characterized in that the received signal is output to the arrival direction estimating means without standardizing the amplitude of the received signal output from the plurality of receivers .

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