JP3454892B2 - Radio source location method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave source position locating method and apparatus for locating a radio wave source, and particularly to a radio wave source position locating method capable of locating a continuous wave radiating source with high accuracy. And equipment.

[0002]

2. Description of the Related Art At present, as a means of communication in power facilities such as power plants and substations in electric power companies, mobile radio for security,
Communication equipment using radio waves such as pagers and small power cordless telephone systems has become indispensable.

On the other hand, in the premises of a power facility, in order to accurately ascertain the patrol / working state and to grasp the state of the power facility, accurate position detection of each patrol / worker and facility diagnosis by radio noise are performed. The need is growing. For this reason,
In order to grasp the radio wave environment in the electric equipment premises, the position of the radio wave source of the communication device is located, or the position of the noise radio wave source is located.

Conventionally, when locating a radio wave source,
For example, an orientation device as shown in FIG. 5 is used.
This radio wave source position locating device was connected to four antennas 12 _{1 to} 12 ₄ for receiving signals radiated from the radio wave source 10 located in a finite plane area 11 and to the respective antennas 12 _{1 to} 12 ₄ . Four receivers 13 _{1 to} 13 ₄ and two arrival time difference detection circuits 14 ₁ and 14 ₂ respectively connected to the combinations of the receivers 13 ₁ and 13 ₂ and the receivers 13 ₃ and 13 _4. It is composed of an arithmetic circuit (MP) 15 which receives the time difference signals from the _two arrival time difference detection circuits 14 ₁ and 14 ₂ and performs a predetermined calculation.

In the case of locating the position of the radio wave source using the locating device having the above-mentioned configuration, the radio waves radiated from the radio wave source 10 are received by the antennas 12 _{1 to} 12 ₄ of the receivers 13 _{1 to} 13 ₄ and reach them. antenna 12 ₁ by the time difference detection circuit 14 ₁
And the waveform of the received signal received from the antenna 12 ₂ and the waveform of the received signal received from the antenna 12 ₃ and the antenna 12 ₄ by the arrival time difference detection circuit 14 ₂ are respectively compared, and each antenna 12 ₁ from the radio wave source 10 is compared. ~ 12
_This is done by detecting the difference in the arrival time of the signal to ₄ . That is, when the radio wave from the radio wave source 10 is a continuous wave, as shown in FIG. 6, and when the radio wave from the radio wave source 10 is a discontinuous wave, as shown in FIG. The position of the radio wave source is located by measuring the arrival time difference Δt.

[0006]

However, according to the conventional radio wave source position locating device, when the radio wave emitted from the radio wave source is a continuous wave, the arrival time difference Δt and Δt + n × 1 / f (n =
1, 2, 3, ...) cannot be discriminated.
Uncertainty of x1 / f may occur, which not only lowers the accuracy of location determination of the radio wave source but also makes location impossible.

Therefore, an object of the present invention is to provide a radio wave source position locating method and apparatus capable of locating a radio wave source radiating a continuous wave with high accuracy.

[0008]

The present invention SUMMARY OF THE INVENTION In view of the above problems, because the to be orientation with high precision even in radio sources for emitting a continuous wave, the radio wave source located on a finite planar area
It receives the signal emitted as a continuous wave at least two at a position determined by measuring the phase difference between the received signals as a cross-correlation function, even a virtual signal is assumed to have been emitted from a plurality of points of the plane area small without 2 The cross-correlation function is the phase difference between the virtual received signals, assuming that they are received at one position.
Then , the measurement-based cross-correlation function is compared with the calculation-based cross-correlation function corresponding to a plurality of points , and the cross-correlation closest to the measurement-based cross-correlation function is calculated.
The function or cross-correlation function <br/> et select based on a corresponding operation to a plurality of points, the radio source position location method to be orientation points corresponding to the cross-correlation function selected as the location of the radio source It is provided.

Further, a radio wave source position locating device of the present invention which achieves the above-mentioned object is provided from a radio wave source located in a finite plane area.
Interacting with the at least two receiving means for receiving the signals radiated at least two at the position, the phase difference between the received signals received by at least two receiving means as a continuous wave
A phase difference measuring means for measuring as a correlation function, and a phase difference between virtual received signals when virtual signals assumed to be emitted from a plurality of points in a plane area are received at at least two positions as a cross-correlation function. determined by calculation, by comparing the cross-correlation function based on operation corresponding to the cross-correlation function and a plurality of points based on the measurement, the cross-correlation based on the measurement
The cross-correlation function that most closely approximates the function corresponds to multiple points
Select from the cross-correlation function based on the operation and select the cross phase
It is configured to locate the point corresponding to the function as the position of the radio wave source.

The receiving means comprises an antenna for receiving a signal radiated from a radio wave source, a low noise amplifier for amplifying the received signal received by the antenna to a predetermined level, and a limiter for keeping the amplitude of the amplified received signal constant. A variable resistance attenuator that attenuates and adjusts the level of a received signal whose amplitude is constant to a predetermined level, and a phase shifter that calibrates the phase shift that occurs during the receiving operation between at least two receiving means to be constant. It is configured. Further, the antenna has an omnidirectionality in a horizontal plane or a vertical plane, or has a wide directivity in the direction of a finite plane area.

It is assumed that the above-mentioned calculation means is received by at least two receiving means assuming that a coordinate input section for inputting a finite plane area as coordinates and each point on the coordinates as a radio wave source.
The phase calculation unit that calculates the phase of the virtual received signal that is determined for each point, and the concept that at least two receiving means receive the signal.
Each point of the cross-correlation function from the phase difference of the virtual reception signal constant
A phase difference calculator for calculating with the the phase difference based on the measurement measured by the phase difference measuring means and cross-correlation function
Of the measured phase difference input section, the comparison circuit for comparing the cross-correlation function based on the calculation calculated by the phase difference calculation section and the cross-correlation function based on the measurement input from the measured phase difference input section, In the comparison result, the measurement-based mutual
The cross-correlation function that best approximates the correlation function at each point on the coordinate
It consists of a radio source localization circuit that selects from the cross-correlation function based on the corresponding calculation, and locates the point on the coordinates corresponding to the selected cross-correlation function as the position of the radio source, and a display unit that displays the localization result. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The radio wave source position locating method and apparatus of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram of a radio wave source position locating device according to an embodiment of the present invention. This radio wave source position locator includes a radio wave source 10 located in a finite plane area 11.
4 antennas 12 ₁ to receive signals radiated from
12 ₄ , four receivers 13 _{1 to} 13 ₄ respectively connected to the antennas 12 _{1 to} 12 ₄ , and receivers 13 ₁ to 1
Signal distributors 16 _{1 to} 16 ₄ respectively connected to 3 ₄ and distributing received signals to three outputs, and each receiver 1
Mixers 17 _{1 to} 17 ₆ for outputting a cross-correlation function of two reception signals composed of a combination of 3 _{1 to} 13 ₄ as phase difference signals M _{1,2 to} M _3,4 and mixer outputs M _{1,2 to} M _{3 , 4} to locate the position of the radio wave source.

The receiver 13 (13 _{1 to} 13 ₄ ) has an antenna 12 (12 _{1 to} 12 ₄ ) as shown in FIG.
The low noise amplifier 18 that amplifies the received signal received at 1. to a predetermined level, the limiter 19 that makes the amplitude of the amplified received signal constant, and the level of the received signal whose amplitude is constant is attenuated and adjusted to a predetermined level. The variable resistance attenuator 20 and the phase shifter 21 that keeps the phase shift amount of each receiver 13 constant due to the difference in the path from the antenna 12 to the variable resistance attenuator 20 and the change in the surrounding environment are configured.

As the antenna 12 (12 _{1 to} 12 ₄ ),
An omnidirectional pattern in the horizontal plane or the vertical plane, or a wide directional pattern in the direction of the finite plane region 11 is used.

As shown in FIG. 3, the arithmetic circuit 15 has a coordinate input section 22 for inputting a finite plane area 11 as coordinates, and when each point on the coordinates is assumed to be a radio wave source, it is radiated from it. Phase calculation unit 23 that calculates the phase of the virtual received signal when each of the antennas 12 _{1 to} 12 ₄ is received by each antenna 12 _{1 to} 12, and the cross-correlation function IM from the phase difference between the antennas of the virtual received signal of each point. Phase difference calculator 24 for calculating
And the phase difference signals M _{1,2 to} M _3,4 output from the mixer 17
And a phase difference calculator 24 for inputting the measured phase difference
The cross-correlation relation calculated from the phase difference based on the calculation
A comparator circuit 26 for comparing the number IM and the phase difference signals M _{1,2 to} M _3,4 based on the measurement input from the measurement phase difference input unit 25 ;
In the comparison result of the comparison circuit 26, the phase difference based on the measurement
A value that is most approximate to the signals M _{1,2 to} M _3,4 is selected from the cross-correlation function IM obtained from the phase differences at a plurality of positions based on the calculation,
A radio source locating circuit 27 for locating a point on the coordinate corresponding to the cross-correlation function IM obtained from the selected phase difference as the position of the radio source, and a display unit 28 for displaying the orientation result.

The radio source position locating method of the present invention using the above locator will be described below. First, a plane area 11 having a finite width, which is considered to exist the radio wave source 10, is input as coordinates from the coordinate input unit 22 of the arithmetic circuit 15. That is, as shown in FIG. 4, the coordinate value n of the X-axis of the plane area 11
And the coordinate value m of the Y axis are input, the plane area 11
Is represented as a coordinate composed of n × m points.

When the input from the coordinate input section 22 is completed,
A coordinate signal representing the coordinates of the plane area 11 is output from the coordinate input unit 22 to the phase calculation unit 23. When the phase calculation unit 23 inputs this coordinate signal and assumes n × m points on the coordinate as radio wave sources, when signals radiated from the points are received by the respective antennas 12 _{1 to} 12 _4. The phase of the virtual received signal of is calculated for each point. This calculation result is output to the phase difference calculation unit 24, and the phase difference calculation unit 24 causes each antenna 12
Is it the phase difference between the virtual received signals at each point received at _{1 to} 12 ₄ ?
To calculate the cross-correlation function IM . That is, the cross-correlation function IM is obtained from the six types of virtual phase differences received by the following antennas for each point on the coordinate according to this calculation result. (1) Antenna 12 ₁ and Antenna 12 ₂ (2) Antenna 12 ₁ and Antenna 12 ₃ (3) Antenna 12 ₁ and Antenna 12 ₄ (4) Antenna 12 ₂ and Antenna 12 ₃ (5) Antenna 12 ₂ and Antenna 12 ₄ (6) Antenna 12 ₃ and antenna 12 ₄

On the other hand, the radio wave source 10 existing in the plane area 11
The radiated radio wave S0 from can be expressed as follows using an analysis signal. S0 = P · exp {j (ωt + φ0)} (1) In the equation (1), P is the amplitude, ω is 2πf, f is the frequency,
φ0 is the initial phase.

The signal emitted from the radio wave source 10, are received respectively by antennas 12 ₁ to 12 ₄ of the receiver _131-134. The signal Si received by each of the receivers 13 _{1 to} 13 ₄ can be expressed as follows. In the equation (2), ri is from the radio wave source 10 to each antenna 12
Distance from _{1 to} 12 ₄ , φi is κ · ri, κ is ω / c,
c is the speed of light.

In the receivers 13 _{1 to} 13 ₄ , the antenna 12
_The low noise amplifier 18 amplifies the received signal received at _{1 to} 12 ₄ to a predetermined level, then the limiter 19 makes the amplitude of the received signal constant, and the variable resistance attenuator 20 further sets the received signal level to a predetermined level. Each of the receivers 1 is attenuated to a level and finally caused by a difference in the path from the antenna 12 to the variable resistance attenuator 20 in the phase shifter 21 and a change in the surrounding environment.
After the phase shift amount of 3 is made constant, it is output.

The reception signals output from the receivers 13 _{1 to} 13 _{4 are} output as three reception signals by the signal distributors 16 _{1 to} 16 ₄ and input to the mixers 17 _{1 to} 17 ₆ , respectively. The input signal SCi input to the mixers 17 _{1 to} 17 ₆ can be expressed as follows. SCi = exp {j (ωt + φ0 + φi)} (i = 1 to 4) (3) The inputs to the mixers 17 _{1 to} 17 ₆ are _six types of received signals received by the following antennas. (1) Antenna 12 ₁ and Antenna 12 ₂ (2) Antenna 12 ₁ and Antenna 12 ₃ (3) Antenna 12 ₁ and Antenna 12 ₄ (4) Antenna 12 ₂ and Antenna 12 ₃ (5) Antenna 12 ₂ and Antenna 12 ₄ (6) Antenna 12 ₃ and antenna 12 ₄

The mixers 17 _{1 to} 17 ₆ form the cross-correlation function proportional to the phase difference between the two input received signals by the phase difference signal.
Output as M _{1,2 to} M _3,4 . The output signals Mk, l from the mixers 17 _{1 to} 17 ₆ can be expressed as follows. Mk, l = SCk.SCl ^* = exp {j (φk-φl)} (k = 1 to 3, l = k + 1 to 4) (4) In the formula (4), * represents a complex conjugate. The mixer output Mk, l is proportional to the cosine of the value of the phase difference φk−φl of the signals received by the respective antennas 12 _{1 to} 12 ₄ .

The phase difference signal M _{1, 2} ~M _{3, 4} which are outputted from the mixer 17 _{1-17 6} is input to the arithmetic circuit 15, the arithmetic circuit 15, a phase difference calculation section 24 described above in the comparison circuit 26 Equation (4) from the virtual phase difference calculated by
A cross-correlation function IM computed using a phase difference signal M _{1, 2} ~M based on measurements input from the measured phase difference input section 25
The difference ΔM between ₃ and ₄ is calculated with respect to all points on the plane area 11 or selected predetermined points, and further, it is searched for from the point on the coordinates of the plane area 11 where ΔM becomes the minimum in the radio wave source locating circuit 27. The point is located as the radio wave source 10, and finally, the result of the orientation is displayed on the display unit 28.

In the above-mentioned radio wave source position locating method, the accuracy of locating the radio wave source 10 depends on the input signal M in the calculator 15.
Since it depends on the number of A / D conversion steps of k and l, the accuracy can be improved by increasing the number of steps and reducing one step, and the resolution can be set to a value smaller than one wavelength. . Theoretically, if the number of A / D conversion steps is increased infinitely, the resolution will approach 0 as much as possible, so that the location of the radio wave source with very good resolution can be expected.

In the above-described embodiments, the case where the number of antennas and receivers is four has been described. However, the number of antennas and receivers should be at least two or more, and the larger the number, the greater the effect and the substantial effect. It is desirable to have 6 or more units.

[0027]

As described above, according to the radio wave source position locating method and apparatus of the present invention, a signal radiated as a continuous wave from a radio wave source located in a finite plane area is received at at least two positions. Cross-correlate phase difference between received signals
Determined by measurement as a function of the phase difference between the virtual reception signal, assuming that received on has been assumed the two even less without a virtual signal position radiation from a plurality of points of the plane area
Calculated as a cross-correlation function and phase based on measurement
Cross-correlation based on cross-correlation function and operation corresponding to multiple points
By comparing the function, based on the cross-correlation function that best approximates the cross-correlation function based on the measurement operation corresponding to a plurality of points
Select from the cross-correlation function, because you to locating the points corresponding to the cross-correlation function is selected as the position of the radio source, it is possible to allow orientation with high precision even in radio sources that emit continuous wave.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an internal configuration of a receiver according to an embodiment.

FIG. 3 is a block diagram showing an internal configuration of an arithmetic circuit according to an embodiment.

FIG. 4 is an explanatory diagram showing a plane area according to an embodiment.

FIG. 5 is a block diagram showing a conventional radio wave source position locating device.

FIG. 6 is an explanatory view showing a conventional radio wave source position locating method.

FIG. 7 is an explanatory diagram showing a conventional radio wave source position locating method.

[Explanation of symbols]

10 radio wave source 11 plane area 12 (12 _{1 to} 12 ₄ ) antenna 13 (13 _{1 to} 13 ₄ ) receiver 14 arrival time difference detection circuit 15 arithmetic circuit 16 _{1 to} 16 ₄ signal distributor 17 _{1 to} 17 ₆ mixer 18 low noise Amplifier 19 Limiter 20 Variable resistance attenuator 21 Phase shifter 22 Coordinate input section 23 Phase calculation section 24 Phase difference calculation section 25 Measurement phase difference input section 26 Comparison circuit 27 Radio wave source localization circuit 28 Display section

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-264712 (JP, A) JP-A-61-162765 (JP, A) JP-A-56-98011 (JP, A) JP-A-57- 119271 (JP, A) JP 63-284481 (JP, A) JP 5-288823 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01S 5/00-5 /14

Claims (5)

(57) [Claims] 1. A signal radiated as a continuous wave from a radio wave source located in a finite plane area is received at at least four positions and the phase difference between the received signals of all combinations is calculated.
Phase differences between virtual reception signals of all combinations when virtual signals assumed to be emitted from a plurality of points in the planar area are received at the at least four positions, which are obtained by measurement as cross-correlation functions. To
For each of the above-mentioned points as a cross-correlation function,
The cross-correlation function based on the measurement is compared with the cross-correlation function based on the calculation corresponding to the plurality of points, and the cross-correlation function that is the closest to the cross-correlation function based on the measurement is calculated. A method for locating a continuous wave radio wave source, characterized by selecting from the cross-correlation function based on the calculation corresponding to the point, and locating the point corresponding to the selected cross-correlation function as the position of the radio wave source. Wherein at least four receiving means for receiving at least four positions signal emitted as a continuous wave from a radio wave source located on finite planar region, all received by the at least four receiving means
It is assumed that the phase difference measuring means for measuring the phase difference between the received signals of the combination of 1 and 2, respectively, and the virtual signals assumed to be radiated from the plurality of points in the plane area are received at the at least four positions. The phase difference between the virtual received signals of all combinations when
For each of the above-mentioned points as a cross-correlation function,
The cross-correlation function based on the measurement is compared with the cross-correlation function based on the calculation corresponding to the plurality of points, and the cross-correlation function most approximate to the cross-correlation function based on the measurement is calculated. select from the cross-correlation function based on the operation that corresponds to the point of continuous wave radio source, characterized in that the point corresponding to the cross-correlation function selected and a calculation means for locating the position of the radio sources Position locator. 3. The receiving means includes an antenna for receiving a signal radiated from the radio wave source, a low noise amplifier for amplifying a received signal received by the antenna to a predetermined level, and an amplitude of the amplified received signal. A limiter that keeps it constant,
A variable resistance attenuator that attenuates and adjusts the level of a received signal whose amplitude is constant to a predetermined level, and a phase shifter that calibrates so that the phase shift generated during the receiving operation between the at least four receiving means is constant. The continuous wave radio wave source position locating device according to claim 2. 4. The continuous wave radio wave source position locating device according to claim 3, wherein the antenna has a non-directivity in a horizontal plane or a vertical plane, or has a wide directivity in the direction of the finite plane region. 5. The calculation means is assumed to be received by the at least four reception means when a coordinate input section for inputting the finite plane area as coordinates and each point on the coordinates as the radio wave source. cross the phase of the virtual reception signals of all the combinations are from the phase difference of a phase calculator for calculating for each point, the virtual reception signal of the all at least four receiving means are supposed to receive a combination a phase difference calculator for calculating the correlation function respectively the points, the measured phase difference input unit for inputting a phase difference based on the measurement measured by the phase difference measuring means as a cross-correlation function, the phase difference computation unit A comparison circuit for comparing the cross-correlation function based on the calculation calculated in step 1 and the cross-correlation function based on the measurement input from the measurement phase difference input unit. Path and the comparison result of the comparison circuit, a cross-correlation function most approximate to the cross-correlation function based on the measurement is selected from the cross-correlation function based on the calculation corresponding to each point on the coordinate, and the selected cross-correlation function is selected. 3. The continuous wave radio wave source position locating device according to claim 2, further comprising a radio wave source locating circuit for locating the point on the coordinates corresponding to a correlation function as a position of the radio wave source, and a display section for displaying a locating result.