JPH09304450A - Equipment for received signal discrimination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable accurate pulse train classification and accurate discrimination in an environment where radar signals are complicated, by classifying pulse trains by using cross-spectrum as the Fourier transform of cross- correlation. SOLUTION: Sample data of each receiving pulse is subjected to complex Fourier transform by an FET processor 4, and peak frequencies and phases are sequentially accumulated in an FET buffer 5. A cross-spectrum processor 6 operates cross-spectrum (Fourier transform of cross-correlation) of the newest and the oldest FET data which are accumulated in the buffer 5. That is, the Fourier transform data of a present signal are compared with those of a part signal. When the peak frequencies are identical to each other, the phase difference Φ of the Fourier transform data of them at the peak frequency is obtained. Then a specified relation is held between the phase difference Φ and the arrival time difference τ. The arrival time difference τ is classified for each radiation source, and accumulated in an arrival time buffer 7. Thereby, accurate pulse train classification is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention receives a pulse-modulated radar signal in a congested radio wave environment, classifies a pulse train for each radiation source of the radar signal, and identifies the radar signal. Regarding the identification device, more specifically, a technique for identifying the signal of the same radiation source or not using the cross spectrum which is the Fourier transform of the cross-correlation, and also performing the accurate pulse repetition directivity and frequency analysis. Involved in.

[0002]

2. Description of the Related Art FIG. 11 is a diagram showing a configuration of a conventional received signal identifying apparatus. In the figure, 1 is an antenna for receiving radio waves, 22 is a receiver for video detecting radar signals received by the antenna 1, and 23. Is a counter for measuring the reception time difference between the signals detected by the receiver 22 and 24 is a pulse classifier for classifying the received signals based on the output of the counter 23.

Next, the operation of the conventional received signal identifying device will be described. The plurality of pulse-modulated signals received by the antenna 1 are demodulated by the receiver 22 into video signals. The counter 23 detects the rising edge of the demodulated video signal and measures the arrival time difference from the preceding pulse. Based on the arrival time difference measured by the counter 23, the pulse classifier 24 classifies the pulse trains in which the received signal periods are similar to each other.

[0004]

Since the conventional received signal identifying apparatus is configured as described above, ambiguity occurs in pulse classification in an environment where signals are congested, and accurate identification is difficult. There was a problem.

The present invention has been made in order to solve the above problems, and particularly to provide a signal discriminating apparatus which discriminates accurately a pulse train under an environment where radar signals are congested and discriminates accurately. With the goal.

[0006]

A received signal identifying apparatus according to the present invention has the following elements. (A)
A receiver for converting a radar signal received by an antenna into an RF or IF signal, (b) an A / D converter for A / D converting the RF or IF signal from the receiver and outputting sample data, (c) sample An FFT processor for FFT operation of data, (d) first buffer memory for accumulating FFT data processed by the FFT processor, (e) FFT data of the latest received signal based on the contents of the first buffer memory, and A cross spectrum processor that obtains a cross spectrum with past FFT data of a received signal, obtains a time difference of arrival between received signals based on the obtained cross spectrum, and groups each pulse train, (f) group each pulse train A second buffer memory that stores data.

Further, it has the following elements.
(A) RF or IF the radar signal received by the antenna
A receiver for converting into a signal, (b) A for A / D converting the RF or IF signal from the receiver and outputting sample data
/ D converter, (c) F for FFT operation of sample data
An FT processor, (d) a buffer memory that stores the FFT data processed by the FFT processor, and (e) a cross spectrum of the pulse FFT data of the latest received signal and the past FFT data is obtained based on the contents of the buffer memory. And (f) a pulse repetition period for obtaining a pulse repetition period for each pulse train based on the arrival time difference of the received signals. Calculator.

Further, it has the following elements.
(A) RF or IF the radar signal received by the antenna
A receiver for converting into a signal, (b) A for A / D converting the RF or IF signal from the receiver and outputting sample data
/ D converter, (c) F for FFT operation of sample data
FT processor, (d) first buffer memory for accumulating FFT data processed by the FFT processor, (e) FFT data of the latest received signal and past FFT data based on the contents of the first buffer memory. A cross spectrum processor for obtaining the cross spectrum and for obtaining the specification data of the received signal based on the obtained cross spectrum, (f) a second buffer memory for accumulating the obtained specification data, (f) a pulse train from the cross spectrum A processor for obtaining and accumulating the frequency and the pulse repetition period for each, (g) a database in which the data of the radar signal is stored in advance, (h) the contents of the second buffer memory and the contents of the database are compared and received. A signal identification processor that identifies radar signals.

Further, the cross spectrum processor is configured to calculate a frequency and a pulse repetition period for each pulse train based on the calculated cross spectrum and accumulate the same in the second buffer. Stores the frequency and pulse repetition period of various radar signals,
The signal identification processor is configured to identify a radar signal by comparing the contents of the second buffer with the contents of the database.

Further, the cross spectrum processor is configured to calculate a frequency and a pulse repetition period for each pulse train based on the calculated cross spectrum, and store the frequency and the pulse repetition cycle in the second buffer. By storing FFT data of various radar signals and frequencies and pulse repetition periods, the signal discrimination processor compares the contents of the second buffer and the contents of the first buffer with the contents of the database. Then, the radar signal is specified.

Further, the cross spectrum processor is configured to group the spectrum data into pulse trains based on the obtained cross spectrum and accumulate them in the second buffer. Spectral data of the radar signal is stored in a pulse train group, and the signal identification processor compares the contents of the second buffer and the contents of the first buffer with the contents of the database to perform radar. It is configured to identify the signal.

Further, the cross spectrum processor is a parallel cross spectrum processor for performing cross spectrum processing in parallel.

Further, it has the following elements.
(A) A receiver for converting a radar signal received by an antenna into a video signal (b) An A / D converter for A / D converting a video signal from the receiver and outputting sample data, (c)
FFT processor for FFTing sample data, (d)
A buffer memory for accumulating the FFT data processed by the FFT processor, (e) a cross spectrum processor for obtaining the cross spectrum of the FFT data of the pulse of the latest received signal and the past FFT data based on the contents of the buffer memory,
(F) A pulse repetition period calculator for obtaining a pulse repetition period for each pulse train of the received signal based on the obtained cross spectrum.

Further, it has the following elements.
(A) RF or IF the radar signal received by the antenna
A receiver for converting into a signal, (b) A for A / D converting the RF or IF signal from the receiver and outputting sample data
/ D converter, (c) F for FFT operation of sample data
The cross spectrum of the FFT data of the pulse of the latest received signal and the past FFT data is obtained based on the contents of the FT processor, (d) the buffer memory that stores the FFT data processed by the FFT processor, and (e) the buffer memory. A cross spectrum processor, (f) a frequency calculator that calculates the frequency of the received signal based on the peak frequency of the calculated cross spectrum.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. 1 to 3 are views for explaining an embodiment of a received signal identifying apparatus according to the present invention.
FIG. 3 is a diagram showing the configuration of the first embodiment. In FIG. 1, 1 is an antenna for receiving radar signals, 2 is a receiver for converting the radar signals received by the antenna 1 into RF signals or IF signals, and 3 is A / D conversion for the converted RF signals or IF signals. And output as sample data A /
D converter, 4 is an FFT processor for Fourier-transforming a signal converted into a digital value by an A / D converter, and 5 is a past pulse FFT buffer for accumulating data Fourier-transformed by the FFT processor 4 (first Buffer), 6 is a cross spectrum processor, and 7 is an arrival time buffer (second buffer). 2 is a diagram showing an example obtained by Fourier transform (amplitude, phase) of the sample data performed by the FFT processor 4, and FIG. 3 is processed by the cross spectrum processor 6 and accumulated in the arrival time buffer 7. It is an example of data that is.

Next, the operation will be described. The plurality of pulse-modulated signals received by the antenna 1 are RF
Alternatively, it is converted to IF and is output as sample data for each received pulse by the A / D converter 3. This sample data is subjected to complex Fourier transform by the FFT processor 4, and the peak frequency and the phase are sequentially accumulated in the past pulse FFT buffer 5. In the cross spectrum processor 6, the latest FFT stored in the past pulse FFT buffer 5 is stored.
A cross spectrum (Fourier transform of cross correlation) between the data and the past FFT data is calculated. Here, there are two types of methods for calculating the cross spectrum, one is a method of performing a complex Fourier transform after taking the mutual relationship between the sample data, and the other is a method of performing a complex Fourier transform for each sample data. This is a method of calculating the correlation of the amplitude and the phase between the Fourier transform data after that. Embodiment 1
In, the latter method is used. Specific processing in the cross spectrum processor 6 will be described. The cross spectrum processor 6 compares the Fourier transform data of the present signal and the past signal to determine whether the peak frequencies are the same. When the peak frequencies are the same, that is, when radio waves from the same radiation source are used, the phase difference Φ between the Fourier transform data of the two at the peak frequency is taken, and the following (1 ) The relationship of formula is established. τ = Φ / (2πf) (f is the peak frequency of the amplitude) (1) Therefore, the data of this arrival time difference is classified for each radiation source as shown in FIG. 3, and accumulated in the arrival time buffer 5. Accurate pulse system classification can be performed as described above.

Embodiment 2 FIG. FIG. 4 is a diagram showing the configuration of another embodiment of the received signal identifying apparatus according to the present invention. In the figure, 8 is a parallel cross spectrum processor for performing cross spectrum processing in parallel. Embodiment 1
The same components as those in FIG. In the second embodiment, in the first embodiment, the cross spectrum processing is performed by sequentially performing the cross spectrum with the past pulses accumulated in the past FFT buffer 5 one by one. The parallel cross spectrum processor 8 in the form 2 of (1) above simultaneously processes the current Fourier transform data and the past Fourier transform data in parallel. By thus performing the cross spectrum processing in parallel, the cross spectrum processing time can be significantly shortened.

Embodiment 3. FIG. 5 is a diagram showing the configuration of still another embodiment of the received signal identifying apparatus according to the present invention. In the figure, 9 is a pulse repetition period calculator for calculating the pulse repetition interval (cycle). In addition, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted. In the third embodiment, a pulse repetition period calculator 9 is provided in place of the arrival time buffer in the first and second embodiments,
Based on the pulse arrival time difference for each signal calculated by the parallel cross spectrum processor 8, a pulse repetition period important for classification of radar signals is obtained. By doing so, the pulse repetition period calculated by the pulse repetition period calculator 9 can be directly accumulated by providing a pulse repetition period buffer (not shown).

Embodiment 4 FIG. 6 is a diagram showing the configuration of still another embodiment of the received signal identifying apparatus according to the present invention, in which 10 is a receiver for video-detecting the radar signal received by the antenna 1, and 11 is an FFT processor. A pre-pulse FFT buffer for storing Fourier-transformed data, and 12 is a pulse repetition period calculator. In addition, the same components as those in Embodiments 1 to 3 are designated by the same reference numerals, and the description thereof will be omitted. In the first to third embodiments, the FFT processing is performed using the RF signal or IF signal converted by the receiver, but in the fourth embodiment, the pulse repetition period is used using the video signal. It is designed to measure. The pulse repetition period of only the same pulse train is measured by taking the correlation between the FFT-converted current pulse and the previous pulse stored in the previous pulse FFT buffer 11. It is possible to obtain an effect equivalent to that of the form 3.

Embodiment 5. FIG. 7 is a diagram showing the configuration of still another embodiment of the received signal identifying apparatus according to the present invention, in which 13 is a frequency calculator. The same components as those in Embodiments 1 to 4 are designated by the same reference numerals, and the description thereof will be omitted. In the fifth embodiment, the receiver 10 in the fourth embodiment is used as a receiver 2 for video detection, and a frequency calculator 13 is provided in place of the pulse repetition period calculator so that a cross spectrum processor 6 can be provided. The frequency of the radar signal received is accurately obtained from the obtained peak frequency of the cross spectrum. Since the cross spectrum is basically an integral calculation, it is possible to improve the accuracy according to the number of integrations.

Embodiment 6 FIG. 8 is a diagram showing a configuration of still another embodiment of the received signal identifying apparatus according to the present invention, in which 14 is a pulse repetition period buffer and 15 is a pulse repetition period buffer.
Is a specification database, and 16 is a signal identification processor. The same parts as those in the second embodiment are designated by the same reference numerals,
The description is omitted. In the sixth embodiment, the classified and highly accurate pulse repetition period and the measured value of the frequency, which are the processing results in the parallel cross spectrum processor 8, are accumulated in the frequency and pulse repetition period buffer 14, and are stored in advance. The signal discrimination processor 16 performs comparison with the pulse repetition periods and frequencies of various radars stored in the original database 15 for accurate signal discrimination. For example, when the following pulse repetition period and frequency are obtained by the cross spectrum processing, this signal can be identified as the signal 2 by comparing with the specification database 15.・ Measurement result: pulse repetition frequency 1020.5 ± 1.2 μs frequency 8021.5 ± 0.3 MHz ・ Database: pulse repetition period frequency signal 1: 900.5 ± 10.0 μs 7319.4 ± 15 MHz signal 2: 1018.5 ± 10.0 μs 8020.2 ± 15 MHz Signal 3: 2111.8 ± 10.0 μs 9321.1 ± 15 MHz

Embodiment 7 FIG. FIG. 9 is a diagram showing a configuration of still another embodiment of the received signal identifying apparatus according to the present invention, in which 17 is an FFT, specification database, 18
Is a signal identification processor. The same parts as those in Embodiment 6 are designated by the same reference numerals, and the description thereof will be omitted. In the seventh embodiment, the FFT data is also stored in the specification database 15 according to the sixth embodiment, and the signal identification processor 18 also uses the FFT data for comparison. Also, it becomes possible to deal with a signal whose frequency is changing within a pulse, and it is possible to identify a signal with higher accuracy.

Embodiment 8 FIG. FIG. 10 is a diagram showing the configuration of still another embodiment of the received signal identifying apparatus according to the present invention. In the figure, 19 is a pulse group FFT buffer, 20 is a spectrum database, and 21 is a signal identification processor. The same parts as those in Embodiment 6 are designated by the same reference numerals, and the description thereof will be omitted. In the eighth embodiment, a pulse group FFT buffer 19 is used instead of the frequency / pulse repetition period buffer in the sixth embodiment.
A spectrum data database 20 storing spectrum data for each pulse group is provided as a database, and signal discrimination is performed by a signal discrimination processor 21 for comparison. By doing so, it is possible to perform highly accurate signal identification with respect to signals that are changing in pulse group units instead of pulse trains.

[0024]

As described above, according to the present invention, the pulse train classification is performed using the cross spectrum which is the Fourier transform of the cross-correlation, so that the ambiguity of the analysis generated by the conventional device can be eliminated. it can.

Since the pulse repetition period calculator is provided, the pulse period can be directly obtained from the pulse arrival time difference.

Further, since the specification database concerning the radar signal is provided so as to be compared with the specification of the received signal, the signal identification becomes easy.

Further, since the frequency of the radar signal and the pulse repetition period are registered in the database as the specification data, the received signal can be accurately specified.

Further, since the FFT data is also registered in the database as the specification data, the received signal can be specified more accurately.

Further, since the spectrum data is registered in the database, the signals which are changing in pulse group units instead of pulse trains
It is possible to identify signals with high accuracy.

Further, since the parallel cross spectrum processor for performing the cross spectrum in parallel is provided, the processing can be performed at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a first embodiment of a received signal identifying apparatus according to the present invention.

FIG. 2 is a diagram showing a principle of a cross spectrum.

FIG. 3 is a diagram showing an example of contents of an arrival time buffer.

FIG. 4 is a diagram showing the configuration of a second embodiment of the received signal identifying apparatus according to the present invention.

FIG. 5 is a diagram showing a configuration of a third embodiment of the received signal identifying apparatus according to the present invention.

FIG. 6 is a diagram showing the configuration of a fourth embodiment of the received signal identifying apparatus according to the present invention.

FIG. 7 is a diagram showing the configuration of a fifth embodiment of the received signal identifying apparatus according to the present invention.

FIG. 8 is a diagram showing the configuration of a sixth embodiment of the received signal identifying apparatus according to the present invention.

FIG. 9 is a diagram showing the configuration of a seventh embodiment of the received signal identifying apparatus according to the present invention.

FIG. 10 is a diagram showing the configuration of an eighth embodiment of the received signal identifying apparatus according to the present invention.

FIG. 11 is a diagram of a conventional received signal identifying device.

[Explanation of symbols]

1 antenna, 2 receiver, 3 A / D converter, 4 F
FT processor, 5 past pulse FFT buffer, 6 cross spectrum processor, 7 arrival time buffer, 8 parallel cross spectrum processor, 9 pulse repetition period calculator, 10 receiver, 11 previous pulse FFT buffer, 1
2 pulse repetition period calculator, 13 frequency calculator, 1
4 frequency, pulse repetition period buffer, 15 specification database, 16 signal identification processor, 17 FFT, specification database, 18 signal identification processor, 19 pulse group FFT buffer, 20 spectrum database, 21 signal identification processor.

Claims (9)

[Claims] 1. A received signal identifying device (a) having the following elements, wherein a radar signal received by an antenna is RF or IF.
A receiver for converting into a signal, (b) A for A / D converting the RF or IF signal from the receiver and outputting sample data
/ D converter, (c) F for FFT operation of sample data
FT processor, (d) first buffer memory for accumulating FFT data processed by the FFT processor, (e) FFT data of the latest received signal and past received signals based on the contents of the first buffer memory. A cross spectrum processor for obtaining a cross spectrum with the FFT data, obtaining an arrival time difference between received signals based on the obtained cross spectrum, and performing grouping for each pulse train, (f) accumulating data grouped for each pulse train 2 buffer memories. 2. A received signal identifying device (a) having the following elements, wherein a radar signal received by an antenna is RF or IF.
A receiver for converting into a signal, (b) A for A / D converting the RF or IF signal from the receiver and outputting sample data
/ D converter, (c) F for FFT operation of sample data
An FT processor, (d) a buffer memory that stores the FFT data processed by the FFT processor, and (e) a cross spectrum of the pulse FFT data of the latest received signal and the past FFT data is obtained based on the contents of the buffer memory. And (f) a pulse repetition period for obtaining a pulse repetition period for each pulse train based on the arrival time difference of the received signals. Calculator. 3. A received signal identifying device (a) having the following elements, wherein a radar signal received by an antenna is RF or IF.
A receiver for converting into a signal, (b) A for A / D converting the RF or IF signal from the receiver and outputting sample data
/ D converter, (c) F for FFT operation of sample data
FT processor, (d) first buffer memory for accumulating FFT data processed by the FFT processor, (e) FFT data of the latest received signal and past FFT data based on the contents of the first buffer memory. A cross spectrum processor for obtaining the cross spectrum and for obtaining the specification data of the received signal based on the obtained cross spectrum, (f) a second buffer memory for accumulating the obtained specification data, (f) a pulse train from the cross spectrum A processor for obtaining and accumulating the frequency and the pulse repetition period for each, (g) a database in which the data of the radar signal is stored in advance, (h) the contents of the second buffer memory and the contents of the database are compared and received. A signal identification processor that identifies radar signals. 4. The cross spectrum processor is configured to obtain a frequency and a pulse repetition period for each pulse train based on the obtained cross spectrum and accumulate the pulse repetition period in the second buffer. By storing frequencies and pulse repetition periods of various radar signals, the signal identification processor is configured to identify the radar signal by comparing the contents of the second buffer with the contents of the database. The received signal identifying device according to claim 3, which is characterized in that. 5. The cross spectrum processor is configured to obtain a frequency and a pulse repetition period for each pulse train based on the obtained cross spectrum and accumulate the pulse repetition period in the second buffer. By storing FFT data of various radar signals and frequencies and pulse repetition periods, the signal discrimination processor compares the contents of the second buffer and the contents of the first buffer with the contents of the database. The received signal identifying apparatus according to claim 3, wherein the received signal identifying apparatus is configured to identify the radar signal. 6. The cross spectrum processor is configured to group spectrum data into pulse trains based on the obtained cross spectrum and accumulate the pulse data in the second buffer. Spectral data of the radar signal is stored in a pulse train group, and the signal identification processor compares the contents of the second buffer and the contents of the first buffer with the contents of the database to perform radar. The received signal identifying device according to claim 3, wherein the received signal identifying device is configured to identify a signal. 7. The received signal identifying apparatus according to claim 1, wherein the cross spectrum processor is a parallel cross spectrum processor that performs cross spectrum processing in parallel. 8. A reception signal identification device (a) having the following elements: (a) a receiver for converting a radar signal received by an antenna into a video signal (b): A / D conversion of a video signal from the receiver to obtain sample data. Output A / D converter, (c)
FFT processor for FFTing sample data, (d)
A buffer memory for accumulating the FFT data processed by the FFT processor, (e) a cross spectrum processor for obtaining the cross spectrum of the FFT data of the pulse of the latest received signal and the past FFT data based on the contents of the buffer memory,
(F) A pulse repetition period calculator for obtaining a pulse repetition period for each pulse train of the received signal based on the obtained cross spectrum. 9. A received signal identifying device (a) having the following elements, wherein a radar signal received by an antenna is RF or IF.
A receiver for converting into a signal, (b) A for A / D converting the RF or IF signal from the receiver and outputting sample data
/ D converter, (c) F for FFT operation of sample data
The cross spectrum of the FFT data of the pulse of the latest received signal and the past FFT data is obtained based on the contents of the FT processor, (d) the buffer memory that stores the FFT data processed by the FFT processor, and (e) the buffer memory. A cross spectrum processor, (f) a frequency calculator that calculates the frequency of the received signal based on the peak frequency of the calculated cross spectrum.