JP2005195347A - Direction search sensor, and radio wave emission source position estimation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direction search sensor, and a radio wave emission source position estimation system capable of shortening a time until receiving a signal by a radio wave to estimate quickly a radio wave emission source position. <P>SOLUTION: Each of the plurality of respective direction search sensors 20<SB>1</SB>-20<SB>3</SB>for estimating a radio wave arrival direction is provided with a reference antenna 31 for receiving a pseudo-GPS-signal spectrally diffused by a PN code, the first reception part 30 including a frequency conversion part 32 for frequency-converting the received pseudo-GPS-signal, a matched filter 34 for correlating a frequency converted signal with the set PN code, and a signal detection control part for detecting an output from the matched filter to confirm a signal detection condition, and for resetting frequency control and the received PN code when not detecting the signal, an array antenna 41 for receiving the pseudo-GPS-signal, the second reception part 40 having the constitution same to the first reception part, and a direction search processing part 50 for estimating the radio wave arrival direction, based on the signals from the radio wave arrival direction and the second reception part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a direction finding sensor and a radio wave emission source position estimation system, and more particularly to a technique for estimating the arrival direction and emission source position of a pseudo GPS signal.

  Conventionally, a global positioning system (hereinafter referred to as “GPS: Global Positioning System”) is known. In this system, a user has four GPS orbits in six circular orbits at an altitude of about 20,000 km. It can receive radio waves (hereinafter referred to as “GPS signals”) from GPS satellites arranged one by one, and can determine its own position, that is, latitude, longitude, altitude, etc. with high accuracy.

  The user GPS receiver normally receives GPS signals emitted from four or more GPS satellites, and performs self-position calculation based on the received GPS signals. This is called GPS positioning. This GPS positioning has a drawback that the positioning accuracy in the height direction is deteriorated as compared with the horizontal direction because all the GPS satellites are present in the sky.

  In order to make up for this drawback, recently, Pseudolite has been studied in which a pseudo-GPS transmitter or a terrestrial repeater transmitter is installed on the ground to form a pseudo-GPS. The ground pseudo GPS transmitter transmits a pseudo GPS signal substantially the same as a GPS satellite. The terrestrial repeater transmitter once receives the GPS signal, changes only the satellite number in the received GPS signal, and retransmits it as a pseudo GPS signal. This pseudo-GPS has the advantage that the positioning accuracy is improved for the user GPS receiver.

  In addition, as a technology for receiving GPS signals, a correlation detection method using a matched filter that can reduce the amount of memory mounted to reduce the size and cost while reducing the calculation time, and a GPS receiver to which the correlation detection method is applied Is known (see, for example, Patent Document 1). A digital matched filter applied to a synchronization acquisition unit in a GPS receiver removes a negative frequency component from an FFT processing unit that performs FFT processing on an IF signal and a frequency domain signal obtained by the FFT processing unit. A negative frequency elimination filter, a memory for buffering the frequency domain signal obtained by the negative frequency elimination filter, a spreading code generator for generating the same spreading code as the spreading code in the RF signal from the GPS satellite, and An FFT processing unit that performs FFT processing on the spread code generated by the spread code generator and a memory that buffers at least the frequency domain signal obtained by the FFT processing unit are configured.

As another related technique, there is known a radio wave arrival direction measuring apparatus that simultaneously receives a plurality of radio waves and measures the arrival direction of the radio waves (see, for example, Patent Document 2). This radio wave arrival direction measuring apparatus supplies a received signal from an antenna to an FFT processor via an amplifier, a mixer and a single local oscillator, a filter, and an A / D converter, and the phase of the frequency channel. Let the value be calculated. The output phase value of the FFT processor is supplied to the signal processor via the memory, and the arrival direction is calculated. According to this radio wave arrival direction measuring apparatus, it becomes possible to simultaneously obtain the phase value of a communication wave existing in a wide band (about several MHz) by combining a high-speed A / D converter and an FFT processor. By using a signal processor that performs a phase comparison operation from this phase value, the arrival directions of a plurality of radio waves can be obtained in a short time.
JP 2003-258682 A JP-A-10-212422

  However, the above-described pseudo GPS has the advantages described above when the ground pseudo GPS transmitter and the ground repeater transmitter are normal, but becomes an interference source when an abnormality such as a failure occurs. As a result, there are cases where the accuracy is deteriorated compared to the positioning using only the GPS satellite, or problems such as reception interruption from the GPS satellite are interrupted.

  In this case, if the location of the interference source is identified, the impact of the problem can be minimized by notifying the operations manager immediately, but if the location is not clear, the operations manager If it is not known, it is necessary to quickly identify the position of the interference source. However, the reception of the pseudo GPS signal requires a lot of time as in the case of the reception of the GPS signal.

  The present invention has been made in order to solve the above-described problems, and is capable of quickly estimating a radio wave emission source position using a plurality of direction finding sensors and a plurality of the direction finding sensors capable of shortening the time until reception of a signal by radio waves. An object of the present invention is to provide a radio wave emission source position estimation system.

  In order to solve the above problems, a direction finding sensor according to the present invention includes a reference antenna that receives a pseudo-GPS signal that is spectrum-spread with a PN code, and a frequency converter that performs frequency conversion on the pseudo-GPS signal received by the reference antenna. 1 frequency conversion unit, a first matched filter that correlates a frequency-converted signal with the first frequency conversion unit and a set PN code, and detects a signal detection state by detecting an output of the first matched filter A first reception unit including a first signal detection control unit configured to perform frequency control and resetting of the reception PN code when the signal cannot be detected, an array antenna that receives the pseudo GPS signal, and the array antenna A second frequency conversion unit that converts the frequency of the received pseudo GPS signal, a signal that is frequency-converted by the second frequency conversion unit, and a set P A second matched filter that correlates with the code, and a second signal that detects the signal detection state by detecting the output of the second matched filter, and performs frequency control and resetting of the received PN code if the signal cannot be detected. A second receiving unit including a detection control unit, and a direction search processing unit that estimates a radio wave arrival direction based on signals from the first receiving unit and the second receiving unit.

In addition, the radio wave emission source position estimation system according to the present invention is spread spectrum with a PN code based on a plurality of direction finding sensors for estimating a radio wave arrival direction, and information indicating the direction of radio wave arrival obtained from the plurality of direction finding sensors. A position processing unit that estimates the emission source position of the pseudo GPS signal, and each of the plurality of direction finding sensors includes a reference antenna that receives the pseudo GPS signal;
A first frequency converter that converts the frequency of the pseudo GPS signal received by the reference antenna; a first matched filter that correlates a signal that is frequency-converted by the first frequency converter and a set PN code; A first reception unit including a first signal detection control unit that detects a signal detection state by detecting an output of the first matched filter and performs frequency control and resetting of a reception PN code when the signal cannot be detected; An array antenna for receiving the pseudo-GPS signal;
A second frequency converter that converts the frequency of the pseudo GPS signal received by the array antenna; a second matched filter that correlates a signal that is frequency-converted by the second frequency converter and a set PN code; A second reception unit including a second signal detection control unit that detects the output of the second matched filter to confirm a signal detection state and performs frequency control and resetting of the reception PN code when the signal cannot be detected; And a direction finding processing unit for estimating a radio wave arrival direction based on signals from the first receiving unit and the second receiving unit.

  According to the direction finding sensor according to the present invention, a matched filter is provided in the first receiving unit and the second receiving unit, and a correlation between the frequency-converted signal and the set PN code is obtained to obtain a received wave signal. Since it comprised so, the time until it receives a pseudo GPS signal can be shortened. Further, according to the radio wave emission source position estimation system according to the present invention, the radio wave emission source position can be quickly estimated by using a plurality of direction finding sensors. As a result, the operation manager can be notified immediately of the position of the interference source.

  Hereinafter, a direction finding sensor and a radio wave emission source position estimation system according to an embodiment of the present invention will be described in detail with reference to the drawings.

First, the concept of the radio wave emission source position estimation system according to the present invention will be described with reference to the conceptual diagram shown in FIG. FIG. 1 shows a radio wave emission source position estimation system 10 according to the present invention, in which a terrestrial pseudo GPS transmitter 13 and a terrestrial repeater are added to a normal GPS composed of _four GPS satellites 11 _{1 to} 11 ₄ and a user GPS receiver 12. The figure shows a state applied to a pseudo GPS configured by adding a transmitter 14.

The GPS satellites 11 _{1 to} 11 ₄ transmit GPS signals. The GPS signals transmitted from the GPS satellites 11 _{1 to} 11 ₄ are received by the ground pseudo GPS transmitter 13 and the ground repeater transmitter 14 existing on the ground.

  The ground pseudo GPS transmitter 13 transmits a pseudo GPS signal substantially the same as that of a GPS satellite. The pseudo GPS signal transmitted from the ground pseudo GPS transmitter 13 is received by the user GPS receiver 12.

The terrestrial repeater transmitter 14 temporarily receives GPS signals transmitted from the GPS satellites 11 _{1 to} 11 ₄ , changes only the satellite numbers in the received GPS signals, and retransmits them as pseudo GPS signals. The pseudo GPS signal transmitted from the ground repeater transmitter 14 is received by the user GPS receiver 12.

The user GPS receiver 12 receives the GPS signals from the GPS satellites 11 _{1 to} 11 ₄ and the pseudo GPS signals from the ground pseudo GPS transmitter 13 and the ground repeater transmitter 14 and performs self-position calculation. As a result, positioning can be performed with high accuracy.

The radio wave emission source position estimation system 10 is used in addition to the above-described pseudo GPS. The radio wave emission source position estimation system 10 includes three direction finding sensors 20 _{1 to} 20 ₃ for estimating the arrival direction of the pseudo GPS signal and a position processing unit 21 for estimating the radio wave emission source position. .

  The number of direction finding sensors is not limited to three, but may be plural. In addition to the case where the direction finding sensor 20 is fixedly installed on the ground, the direction finding sensor 20 may be mounted on the direction finding sensor vehicle 10 ′ and configured to be movable.

In the radio wave emission source position estimation system 10, when the ground pseudo GPS transmitter 13 or the ground repeater transmitter 14 constituting the pseudo GPS becomes an interference source, the three GPS sensors 20 _{1 to} 20 ₃ receive the pseudo GPS signals. To do. Then, each of the direction finding sensors 20 _{1 to} 20 ₃ estimates the radio wave arrival direction of the interference source. Direction data representing the direction of arrival of radio waves estimated by the direction finding sensors 20 _{1 to} 20 ₃ is sent to the position processing unit 21.

Position processing unit 21, based on the square probe sensor 20 ₁ to 20 3 direction data sent from the ₃ to estimate the position of the interference source (radio wave source) in a known manner. As a result, the location of the interference source can be promptly notified to the operation manager, so that the influence of the problem can be minimized.

Meanwhile, in order to estimate the arrival direction of the pseudo GPS signal in rectangular probe sensor 20 ₁ to 20 _3, it must first receive the pseudo GPS signal. Similar to the GPS signal, the pseudo GPS signal is a signal having a spectrum spread over a wide band by a pseudo-random noise code (PN code). Such person probe sensor 20 ₁ to 20 ₃ may be configured to receive a pseudo GPS signal incorporating the same receiving function and user GPS receiver 12.

  In general, the user GPS receiver 12 first performs a sliding search for obtaining a PN code correlation for distance measurement. The sliding search is a technique for detecting a phase that can be synchronized by taking a correlation while shifting the phase between a PN code held by itself and a received signal input in time series and detecting a peak of the correlation. After the PN code correlation is obtained by this sliding search, the PN code is continuously tracked by DLL (Delay Locked Loop) control or the like. Then, the PN code phase in the state of tracking in the user GPS receiver 12 is used as distance measurement information.

  In order for the user GPS receiver 12 to receive a GPS signal (the same applies to the pseudo-GPS signal), processing for detecting correlation is performed by a sliding search. It is well known that this requires a lot of time. In particular, when there is no information as to which satellite number the PN code pattern to be received belongs to, it is necessary to perform a sliding search with all satellite numbers. Usually, it takes about 1 to 2 minutes to receive a signal from one GPS satellite.

Therefore, the square probe sensor 20 ₁ to 20 _3, rather than the sliding search technique to the receiver for receiving the signal is employed in a general GPS receiver, a matched filter capable of correlating a short time Is adopted. Although the matched filter has a disadvantage that distance measurement cannot be performed, the direction finding sensors 20 _{1 to} 20 ₃ only need to be able to receive (PN code correlation) from the viewpoint that only the direction of arrival of radio waves needs to be known.

FIG. 2 is a block diagram showing the configuration of the direction finding sensors 20 _{1 to} 20 ₃ . The configuration of each of the direction finding sensors 20 _{1 to} 20 ₃ is the same. Therefore, hereinafter, the direction finding sensors 20 _{1 to} 20 ₃ will be described as “the direction finding sensor 20” unless particularly distinguished. FIG. 2 shows an example in which a matched filter is applied to the direction finding sensor 20 configured as a radio holography.

  The direction finding sensor 20 includes a first receiving unit 30, a second receiving unit 40, and a direction finding processing unit 50.

  A reference antenna 31 is connected to the first receiving unit 30. The direction finding sensor 20 includes a frequency conversion unit 32, an A / D converter 33, a matched filter 34, a D / A converter 35, a low-pass filter (LPF) 36, a signal detection control unit 37, and a local oscillator 38. .

  The frequency converter 32 converts the high-frequency signal transmitted from the reference antenna 31 into an IF signal in a frequency band that can be sampled by the A / D converter 33 in the subsequent stage, in accordance with the signal from the local oscillator 38. The IF signal obtained by the conversion by the frequency converter 32 is sent to the A / D converter 33.

  The A / D converter 33 samples the IF signal sent from the frequency converter 32 and converts it into a digital signal. The sampling data obtained by the A / D converter 33 is sent to the matched filter 34.

  The matched filter 34 includes a shift register 60, a register 61, a multiplier circuit 62, and an adder (SUM) 63.

  The shift register 60 is configured by slidably connecting 1023 (or 1023 × integer) registers equal to the number of PN code strings of the GPS signal. Sampling data from the A / D converter 33 is input to the shift register 60. The 1023 (or 1023 × integer) data output in parallel from the shift register 60 is sent to one input terminal of the multiplication circuit 62.

  The register 61 is a 1023 bit (or 1023 × integer) register, and is set with a PN code string to be received. The PN code period is defined as 1 ms. Therefore, the contents of the register 61 are set to a 1 ms PN code pattern. The 1023 (or 1023 × integer) data output from the register 61 in parallel is sent to the other input terminal of the multiplication circuit 62.

  The multiplication circuit 62 takes the product of 1023 (or 1023 × integer) data from the shift register 60 and 1023 (or 1023 × integer) data from the register 61 and outputs the product. The 1023 (or 1023 × integer) data output from the multiplication circuit 62 is sent to the adder 63.

  The adder 63 adds up 1023 (or 1023 × integer) data from the multiplication circuit 62. Therefore, if 1023 (or 1023 × integer) data from the shift register 60 and 1023 (or 1023 × integer) data from the register 61 match, the adder 63 outputs a large value. If there is no match, a small value is output. The output of the adder 63 is used as a correlation value. Accordingly, even when the first reception is considered in about 1 ms of the PN code cycle, the correlation can be obtained in about 2 ms at the maximum. The output of the adder 63 is sent to the D / A converter 35.

  The D / A converter 35 converts the signal output from the matched filter 34 every 1 ms into an analog signal. As a result, an analog signal having an envelope (envelope) corresponding to the data every 1 ms output from the matched filter 34 is obtained. Since this analog signal is created based on data every 1 ms, its frequency is 500 Hz or less. The analog signal output from the D / A converter 35 is sent to the low pass filter 36.

  The low pass filter 36 has a cutoff frequency of 500 Hz, and cuts a high frequency component of the analog signal from the D / A converter 35. As a result, a signal having the same shape as the received wave is obtained from the low-pass filter 36. The signal output from the low-pass filter 36 is sent to the signal detection control unit 37 and the direction finding processing unit 50.

  The signal detection control unit 37 detects the signal from the low-pass filter 36, and sends a frequency control signal for instructing the local oscillator 38 to change the transmission frequency when a significant signal is not obtained by the detection. Further, the signal detection control unit 37 sets the PN code to be received in the register 61 of the matched filter 34 in accordance with the reception control signal from the direction finding processing unit 50.

  In response to the frequency control signal from the signal detection control unit 37, the local oscillator 38 generates a signal having a transmission frequency necessary for converting the received high-frequency signal into an IF signal having an intermediate frequency. The signal generated by the local oscillator 38 is sent to the frequency converter 32.

Here, the frequency f ₀ of the pseudo GPS signal input from the reference antenna 31, for example, by Doppler effect, consider the case where frequency shift occurs in the range of f ₀ -10kHz~f ₀ + 10kHz as shown in Figure 3. In this case, the order to obtain the signal of the following received wave, the frequency generated by the local oscillator 38, is necessary to determine whether a correlation can be taken by switching one by 500Hz in the range of f ₀ -10kHz~f ₀ + 10kHz is there.

  Therefore, the frequency search range is 20 kHz, and if this is switched in increments of 500 Hz, the frequency switching frequency generated by the local oscillator 38 is 40 times. Here, if the maximum time for detecting the correlation of the PN code is 2 ms, a signal for one set PN code can be received in 80 ms. Therefore, the reception time can be significantly shortened compared with 1 to 2 minutes required for receiving a signal by detecting a correlation by a sliding search adopted in a general user GPS receiver.

  If the satellite number is not known and the PN code is reset, it can theoretically be received in 8 seconds even if 100 types of PN codes are reset.

  An array antenna 41 is connected to the second receiver 40. The configuration and operation of the second receiving unit 40 are the same as the configuration and operation of the first receiving unit 30 described above except that a reception signal is input from the array antenna 41.

  The direction finding processing unit 50 changes the setting of the PN code by sending a reception control signal to the first receiving unit 30 and the second receiving unit 40. Thereby, when the satellite number is not known, a plurality of types of PN codes can be set sequentially.

  Further, the direction finding processing unit 50 sends an antenna switching control signal to the array antenna 41 to instruct switching of elements. Based on the phase information between the signal received by each element sent from the second receiving unit 40 and the signal received by the reference antenna 31 sent from the first receiving unit 30 in response to the antenna switching signal Are obtained, specifically, the elevation angle θ and the azimuth angle ψ in the azimuth direction with respect to the front direction of the array antenna 41. Thereby, the three-dimensional direction from which radio waves arrive can be obtained, and the function as radio holography is realized. As an algorithm for estimating the arrival direction of radio waves, interferometry, the MUSIC method, and other various methods can be used.

Three direction data representing the direction of arrival of radio waves is estimated at each person probe sensors 20 ₁ to 20 ₃ in the above manner is sent to the position processing unit 21 (see FIG. 1). The position processing unit 21, as described above, based on the square probe sensor 20 ₁ to 20 3 direction data sent from the ₃ to estimate the position of the interference source (radio wave source) in a known manner.

  The radio wave emission source position can generally be calculated from radio wave arrival direction information obtained by three or more direction finding sensors. However, the radio wave arrival direction information obtained by the direction finding sensor used in the conventional radio wave monitoring or the like is information on only the azimuth angle on the ground. Therefore, the position information to be estimated is also ground two-dimensional position information.

  In contrast, in the radio wave emission source position estimation system according to the embodiment of the present invention described above, radio holography is used as the direction finding sensor 30, so that the array antenna 41 is placed in the zenith direction as shown in FIG. By installing it toward, information on the elevation angle θ and azimuth angle ψ can be obtained as information on the direction of arrival of radio waves.

As a result, it is possible to estimate a three-dimensional radio wave emission source position by calculating together with elevation angle and azimuth information obtained from a plurality of direction finding sensors. For example, square probe sensor 20 ₁ of the array antenna 41 _1, rectangular the probe sensor 20 _{and second} array antennas 41 ₂ and a square probe sensor 20 ₃ of array antenna 41 _3, by arranging, for example, as shown in FIG. 4 (B) Even if an airplane flying in the sky is a radio wave emission source, its position can be estimated.

In addition, since the GPS signals from the GPS satellites 11 _{1 to} 11 ₄ are also received by installing the array antenna 41 in the zenith direction, it is necessary to distinguish between the GPS signal and the pseudo GPS signal. Since the actual directions of all GPS satellites can be calculated from the GPS almanac data obtained by receiving and demodulating the GPS signal, the GPS signal and the pseudo GPS signal can be distinguished by estimating the arrival direction of the radio wave.

  As described above, according to the radio wave emission source position estimation system according to the embodiment of the present invention, the first receiving unit 30 is provided with the matched filter 34 to obtain the correlation, thereby obtaining the received wave signal. As a result, the time until the pseudo GPS signal is received can be shortened, and the radio wave emission source position can be estimated quickly. As a result, the operation manager can be notified immediately of the position of the interference source.

Further, the direction finding sensors 20 _{1 to} 20 ₃ are provided with a first receiving unit 30 that receives a pseudo GPS signal by the reference antenna 31 and a second receiving unit 40 that receives the pseudo GPS signal by the array antenna 41 to form a radio holography. Since it is configured to function, the three-dimensional position of the radio wave emission source (interference source) can be estimated. Therefore, even if the radio wave emission source is in the sky, for example, the position can be estimated.

  In the above-described embodiment, the direction finding sensor 20 is configured to function as a radio holography. However, the second receiving unit 40 and the array antenna 41 are removed, and only the arrival direction of the pseudo GPS signal is estimated. You can also

  The direction finding sensor and radio wave emission source position estimation system according to the present invention can be applied to a radio wave monitoring system that monitors the radio wave emission source of a pseudo GPS signal.

It is a conceptual diagram which shows the concept of the radio wave emission source position estimation system which concerns on this invention. It is a block diagram which shows the structure of the direction finding sensor used with the radio wave emission source position estimation system which concerns on the Example of this invention. It is a figure for demonstrating the time required until a signal is received in the direction finding sensor shown in FIG. It is a figure for demonstrating the operation | movement which estimates the three-dimensional radio wave emission source position using the radio wave emission source position estimation system which concerns on the Example of this invention as radio holography.

Explanation of symbols

10 radio wave source position estimation system 10 'towards probe sensor wheel 11 ₁ to 11 ₄ GPS satellites 12 user GPS receiver 13 terrestrial pseudo GPS receiver 14 terrestrial repeater transmitters 20, 20 20 ₁ to 20 _3-way probe sensor 21 position processing unit 30 First receiver 31 Reference antenna 32 Frequency converter 33 A / D converter 34 Matched filter 35 D / A converter 36 Low-pass filter 37 Signal detection controller 38 Local oscillator 40 Second receivers 41, 41 _{1 to} 41 ₃ Array antenna 50 Direction search processing unit 60 Shift register 61 Register 62 Multiplication circuit 63 Adder

Claims (4)

A reference antenna that receives a pseudo-GPS signal that has been spread spectrum with a PN code;
A first frequency converter that converts the frequency of the pseudo GPS signal received by the reference antenna; a first matched filter that correlates a signal that is frequency-converted by the first frequency converter and a set PN code; A first reception unit including a first signal detection control unit that detects a signal detection state by detecting an output of the first matched filter and performs frequency control and resetting of a reception PN code when the signal cannot be detected; ,
An array antenna for receiving the pseudo-GPS signal;
A second frequency converter that converts the frequency of the pseudo GPS signal received by the array antenna; a second matched filter that correlates a signal that is frequency-converted by the second frequency converter and a set PN code; A second reception unit including a second signal detection control unit that detects the output of the second matched filter to confirm a signal detection state and performs frequency control and resetting of the reception PN code when the signal cannot be detected; ,
A direction finding processing unit that estimates a radio wave arrival direction based on signals from the first receiving unit and the second receiving unit;
A direction finding sensor characterized by comprising:   The said direction finding sensor is mounted in the movable body which can move, The direction finding sensor of Claim 1 characterized by the above-mentioned. Multiple direction finding sensors that estimate the direction of arrival of radio waves,
A position processing unit that estimates the emission source position of a pseudo GPS signal that is spectrum-spread with a PN code based on information representing the radio wave arrival directions obtained from the plurality of direction finding sensors;
Each of the plurality of direction finding sensors is
A reference antenna for receiving the pseudo GPS signal;
A first frequency converter that converts the frequency of the pseudo GPS signal received by the reference antenna; a first matched filter that correlates a signal that is frequency-converted by the first frequency converter and a set PN code; A first reception unit including a first signal detection control unit that detects a signal detection state by detecting an output of the first matched filter and performs frequency control and resetting of a reception PN code when the signal cannot be detected; ,
An array antenna for receiving the pseudo-GPS signal;
A second frequency converter that converts the frequency of the pseudo GPS signal received by the array antenna; a second matched filter that correlates a signal that is frequency-converted by the second frequency converter and a set PN code; A second reception unit including a second signal detection control unit that detects the output of the second matched filter to confirm a signal detection state and performs frequency control and resetting of the reception PN code when the signal cannot be detected; ,
A direction finding processing unit that estimates a radio wave arrival direction based on signals from the first receiving unit and the second receiving unit;
A radio wave emission source position estimation system comprising: The radio wave emission source position estimation system according to claim 3, wherein a radio holography function is used for the plurality of direction finding sensors.

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