JP2008139056A - Radar signal identifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein a data to be analyzed gets too much to saturate accumulation in a memory and analytical processing for the accumulated data, when analyzing a modulation system for in-pulse modulation, under the condition where a plurality of radar signals is received, and wherein real time performance is lacked thereby. <P>SOLUTION: This radar signal identifier has the first signal processing circuit for detecting pulse specifications (frequency, pulse width, pulse repetition interval or the like) of each radar pulse based on a video signal or the like obtained from the received radar signal, so as to generate a pulse data having a common tendency, and the second signal processing circuit for converting the received radar signal into a digital pulse waveform data to be accumulated in the memory 10, and for detecting the pulse item of the in-pulse modulation, an in-pulse modulation simplified analytical part 7 is provided to analyze simply the presence of the in-pulse modulation, in the first signal processing circuit, and processing for detecting the item of the in-pulse modulation is executed in the second signal processing circuit, when the presence of the modulation is determined as a result of the analysis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radar signal identification device for identifying a generation source of a radar signal from information on a pulse specification of a received radar signal and information on modulation within the pulse.

2. Description of the Related Art Conventionally, there is known a radar signal identification device that detects a feature of a received radar signal and matches a radar transmission signal database owned in advance to identify a radar transmission source.
As such a radar signal identification device, a pulse frequency is detected from a radar signal, and pulse specifications such as a pulse width (PW) and a pulse repetition period (PRI) are obtained from a video signal obtained by envelope detection of the radar signal. A first signal processing system for detecting a signal, and a signal converted from a radar signal into an intermediate frequency (IF) signal is converted into digital pulse waveform data by a high-speed A / D converter, and the converted digital pulse waveform data is stored in a memory A second signal processing system for extracting amplitude characteristics, frequency characteristics, and phase characteristics of modulation within the pulse by reading out digital pulse waveform data from the accumulated memory, and a pulse train characteristic database and an intra-pulse characteristic database. Some have a database management unit for managing the database.
First, the pulse specifications obtained in the first signal processing system are compared with the pulse train characteristic database, and if the type and operation mode of the signal source are identified as a result of the comparison, the same type and operation mode as the data are identified. The waveform data of the signal source is preferentially read out from the intra-pulse characteristic database to identify the individual source. If the type and operation mode of the signal source are not identified as a result of the collation, the intra-pulse modulation data obtained in the second signal processing system and the intra-pulse characteristic database are compared and collated based on the collation result. The pulse train characteristic database or the intra-pulse characteristic database is updated and registered. (See Patent Document 1)

  Also, as the number of radar transmitters adopting the modulation method of intra-pulse modulation is increasing, a radar signal analyzing apparatus for analyzing characteristics inside a pulse and using it for analysis identification has been proposed. Such a radar signal analyzing apparatus includes an RF / IF converter that converts a radio frequency (RF) signal extracted by an antenna into an intermediate frequency (IF) signal, and an A that converts the converted IF signal into digital pulse waveform data. / D conversion unit, converted digital pulse waveform data and memory for storing the arrival time of the pulse, read the stored digital pulse waveform data, and according to a predetermined algorithm, the pulse characteristic data of the digital pulse waveform data Analyze, determine the presence or absence of intra-pulse modulation, specify the modulation method for the digital pulse waveform data that is intra-pulse modulation, and the pulse characteristic data obtained by this pulse analysis unit and the result of specifying the modulation method And a pulse train separation unit that separates and outputs a corresponding pulse train for each modulation method. And performing feature analysis of internal pulse in the radar signal. (See Patent Document 2)

JP 2003-270326 A JP 2005-241360 A

Conventional radar signal analyzers have the following problems.
First, a radar signal discriminating apparatus that only detects pulse specifications by envelope detection is excellent in real-time discrimination, but does not have the ability to analyze the modulation characteristics in the pulse. May be reduced.

  Second, in order to specify the modulation method of intra-pulse modulation, digital pulse waveform data is obtained by performing high-frequency sampling, so that the digital data stored in the memory has a large capacity. In addition, in order to read data from the memory and analyze the modulation method of intra-pulse modulation, a high-performance processor is required because of the large volume of data. For this reason, in the situation where a plurality of radar signals are received, if the amount of data to be analyzed increases, the storage of the memory and the analysis processing of the stored data are saturated, and there is a problem that the real-time property is lacking.

  Further, as disclosed in Patent Document 1, a pulse source detected by envelope detection is compared with a pulse train characteristic database, and a signal source is specified by referring to the intra-pulse characteristic database based on the priority based on the result of the comparison. As a result, the processing time can be shortened and the possibility of misidentification can be reduced. However, even in this Patent Document 1, the modulation method of the intra-pulse modulation is always analyzed, and as described in the second problem, when the data to be analyzed increases, the accumulation of the memory and the analysis of the accumulated data are performed. There is a problem that processing becomes saturated and lacks real-time properties.

  The present invention has been made to solve the above-mentioned problems, and simply analyzes the presence or absence of intra-pulse modulation. As a result, only the target pulse signal analyzed as having intra-pulse modulation is modulated by intra-pulse modulation. It is an object of the present invention to provide a radar signal identification device that improves the real-time performance of radar signal identification.

  A radar signal identification device according to the present invention includes an antenna that receives a radar signal and extracts a high-frequency signal, an RF / IF conversion unit that converts the high-frequency signal extracted by the antenna into an intermediate frequency signal, and a conversion performed by the RF / IF conversion unit. A pulse signal of each radar signal received by the antenna from the received intermediate frequency signal and converted by a first signal processing circuit for generating pulse data having a common tendency and an RF / IF converter A second signal processing circuit for converting each radar signal received by the antenna from the intermediate frequency signal into digital pulse waveform data and storing the digital pulse waveform data in a memory, and detecting specifications of intra-pulse modulation of each radar signal; Analyzes the presence or absence of intra-pulse modulation from the pulse data detected by the signal processing circuit. If the result of the analysis indicates that there is modulation, intra-pulse modulation is performed by the second signal processing circuit. From the intra-pulse modulation simple analysis unit for performing the process of detecting the specifications, the pulse data obtained by the first signal processing circuit and the intra-pulse modulation information obtained by the second signal processing circuit, the target radar And a target data generation unit for generating the target data.

  According to the present invention, the intra-pulse modulation simple analysis unit allows the second signal processing circuit to detect the intra-pulse modulation specifications only for the radar signal pulse analyzed as having intra-pulse modulation. For radar signals that do not employ a method, specifications can be detected and identified in real time as before, and only for radar signals that employ a modulation method of intra-pulse modulation, intra-pulse modulation specifications are detected. Therefore, the analysis and identification capabilities are improved, and the storage time in the memory and the processing load on the analysis can be reduced.

Embodiment 1
Hereinafter, a radar signal identification device according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a block diagram showing a configuration of a radar signal identification device according to Embodiment 1, FIG. 2 is a flowchart showing a processing algorithm of a simple intra-pulse modulation analysis unit of the radar signal identification device, and FIG. 3 is a simple analysis of presence / absence of intra-pulse frequency modulation. FIG. 4 and FIG. 5 are diagrams for explaining simple analysis of the presence / absence of intra-pulse phase modulation.

  In the configuration block diagram shown in FIG. 1, an antenna 1 receives radar signals from a plurality of sources and extracts a radio frequency (RF) signal. The RF / IF converter 2 converts the high frequency signal extracted by the antenna 1 into an intermediate frequency (IF) signal. The detection unit 3 performs envelope detection processing on the intermediate frequency signal extracted by the RF / IF conversion unit 2 and outputs a video signal. The video signal A / D converter 4 converts an analog video signal into a digital signal. The PW / PRI / PA measurement unit 5 calculates the pulse width (PW), pulse repetition period (PRI), pulse amplitude (PA), etc. of each radar pulse from the video signal digitized by the video signal A / D conversion unit 4. Detect the specifications. The frequency measurement unit 6 instantaneously measures the frequency of the intermediate frequency signal converted by the RF / IF conversion unit 2 by an IFM (Instantaneous Frequency Measurement) method. The intra-pulse modulation simple analysis unit 7 detects the presence / absence of modulation by simply analyzing the modulation method of intra-pulse modulation based on the specifications of the pulses measured by the PW / PRI / PA measurement unit 5 and the frequency measurement unit 6. Is.

The pulse train separation unit 8 is a pulse train corresponding to the received radar signal based on the specifications of the pulses such as frequency, PW, PRI, PA, etc. obtained by the PW / PRI / PA measurement unit 5 and the frequency measurement unit 6. Are divided into groups of pulses having a common tendency to generate pulse data. In the first embodiment, the simple analysis result of the intra-pulse modulation obtained by the intra-pulse modulation simple analysis unit 7 is also added to the specifications of the pulse train separation.
Here, separating the pulses having a common tendency into groups includes 1) collecting pulses whose frequencies are approximated, 2) collecting pulses whose pulse width (PW) is approximated, and 3) pulse repetition period ( PRI) is approximated, 4) Pulse amplitude (PA) is approximated, 5) Intra-pulse modulation simple analysis result is summarized, and so on. The pulse trains having a common tendency are separated for each group on the basis of any one or a plurality of parameters.

  The IF signal A / D converter 9 converts the intermediate frequency signal converted by the RF / IF converter 2 into a digital signal. The memory 10 stores the digital signal converted by the IF signal A / D converter 9 as pulse waveform data. The intra-pulse modulation specification detection unit 11 synchronizes the pulse data with the intra-pulse modulation in the intra-pulse modulation simple analysis unit 7 with the pulse waveform data stored in the memory 10 and generates the corresponding pulse waveform data. On the other hand, information such as intra-pulse modulation scheme information, frequency modulation, and phase modulation of each pulse is detected. The target data generation unit 12 generates and outputs target data of a target radar signal from the pulse data from the pulse train separation unit 8 and the intra-pulse modulation specification detection result from the intra-pulse modulation specification detection unit 11. is there.

  In the above configuration, the detection unit 3, the video signal A / D conversion unit 4, the PW / PRI / PA measurement unit 5, the frequency measurement unit 6 and the pulse train separation unit 8 are received by the antenna by envelope detection of the intermediate frequency signal. A first signal processing circuit that detects pulse specifications of each radar signal and generates pulse data having a common tendency is configured. The IF signal A / D conversion unit 9, the memory 10, and the intra-pulse modulation specification detection unit 11 convert each radar signal received by the antenna from the intermediate frequency signal into digital pulse waveform data and store it in the memory, A second signal processing circuit for detecting specifications of intra-pulse modulation of each radar signal is configured.

  Next, the operation in the above configuration will be briefly described. First, in the first signal processing circuit, a radar signal of a pulse received by the antenna 1 is converted into an intermediate frequency signal by the RF / IF converter 2 and input to the detector 3. The detection unit 3 performs envelope detection processing on the intermediate frequency signal to generate a video signal, and inputs the video signal to the video signal A / D conversion unit 4. The video signal A / D conversion unit 4 converts the video signal into a digital signal and inputs the digital signal to the PW / PRI / PA measurement unit 5. The PW / PRI / PA measuring section 5 detects specifications such as the pulse width (PW), pulse repetition period (PRI), and pulse amplitude (PA) of each radar pulse from the digitized video signal. The frequency measurement unit 6 instantaneously measures the frequency of the intermediate frequency signal converted by the RF / IF conversion unit 2 by the IFM method. Specifications such as PW, PRI, PA, and frequency detected in this way are sent to the pulse train separation unit 8 via the intra-pulse modulation simple analysis unit 7, and the pulse train separation unit 8 separates each group of pulses having a common tendency. And sent to the target data generation unit 12. Thus, for the radar signal that does not employ the modulation method of the intra-pulse modulation, the specification data only processed by the first signal processing circuit is compared and collated with the data in the database or the like by the target data generation unit 12 and transmitted. It is possible to detect and identify the source radar signal in real time.

Next, in the second signal processing circuit, the pulse radar signal received by the antenna 1 is converted into an intermediate frequency signal by the RF / IF converter 2 and input to the IF signal A / D converter 9. The IF signal A / D converter 9 converts the intermediate frequency signal into a digital signal and stores the digital signal in the memory 10 as pulse waveform data. The intra-pulse modulation specification detecting unit 11 synchronizes the pulse data with intra-pulse modulation and the pulse waveform data stored in the memory 10, and performs intra-pulse modulation of each pulse with respect to the corresponding pulse waveform data. Information such as the amplitude characteristics, frequency characteristics, and phase characteristics of the method is detected and sent to the target data generation unit 12. In this way, for the radar signal that employs the modulation method of the intra-pulse modulation, the target data generation unit 12 outputs the pulse data from the pulse train separation unit 8 and the intra-pulse modulation specification from the intra-pulse modulation specification detection unit 11. By comparing and collating the detection result with data such as a database, it is possible to detect and identify the specifications of the radar signal.
The processing in the intra-pulse modulation specification detection unit 11 in this second signal processing circuit is performed only when the intra-pulse modulation simple analysis unit 7 detects that intra-pulse modulation is present. This processing is not performed for radar signals that do not employ the method.

Next, the operation of simply analyzing the presence / absence of intra-pulse modulation for each pulse in the intra-pulse modulation simple analysis unit 7 of FIG. 1 is performed using the processing algorithm flowchart shown in FIG. A description will be given based on a criterion for simple determination of the modulation method within the pulse.
First, in step S11 in FIG. 2, the frequency data at each timing inside the pulse obtained by the frequency measuring unit 6 is determined from a frequency value (for example, a rising frequency) of the timing as the frequency of the pulse at a certain level. A line is provided, and the rate at which the frequency data at each timing exceeds the determination line is detected.
For example, in a pulse having a pulse width and amplitude as shown in FIG. 3A, the frequencies F1, F2, F3, F4,... At each timing inside the pulse are measured. On the other hand, as shown in FIG. 3 (b), a determination line F1 ± A is set at a certain vertical position from the rising frequency F1 of the pulse, and the frequencies F1, F2, F3, F4,. Counts the number exceeding the determination line F1 ± A, and if it exceeds a certain percentage (YES), it is determined that there is a frequency modulation method. If the frequency exceeding the determination line F1 ± A is less than a certain percentage (NO), the process proceeds to step S13.

Next, in step S12 of FIG. 2, in the amplitude value (PA) data at each timing inside the pulse used for the measurement of PW, PRI, and PA in the PW / PRI / PA measurement unit 5, It is detected whether or not there has been a sudden drop in the level by a certain amount from the amplitude value.
For example, in a pulse having a pulse width and amplitude as shown in FIG. 4, amplitude values PA1, PA2, PA3, PA4,... At each timing inside the pulse are measured. For a sudden fall of the amplitude, a time width is provided until the amplitude value returns to the original value. If the amplitude value returns to the original amplitude value within that time, it is determined that there is a phase modulation method. When the amplitude value does not return to the original value, the end of the pulse is detected. This is to capture the characteristic that the amplitude inside the pulse suddenly drops at the timing of phase inversion by phase modulation.

  The reason for the sudden drop in the amplitude inside the pulse is that a relatively large wobble occurs in the frequency value at the timing of phase inversion due to phase modulation, so that it temporarily deviates from the filter range before pulse amplitude detection. The level is lowered by the effective width characteristic. For this reason, in step S13 of FIG. 2, the frequency exceeding the determination line F1 ± A, for example, is less than a certain ratio by detecting a rapid fluctuation of the frequency. However, as shown in FIG. If there is a frequency that exceeds the moment, that is, if there is a sudden change in the frequency data at each timing within the pulse by a certain amount from the previous timing frequency, it is simply said that there is a phase modulation method. judge.

For a pulse train that has been analyzed as having intra-pulse modulation by the intra-pulse modulation simple analysis unit 7, the pulse train separation unit 8 sends the information to the target data generation unit 12, and at the same time, the pulse of the second signal processing circuit. A signal is sent to the internal modulation specification detection unit 11 and the second signal processing circuit performs processing for detecting the specification of the internal modulation. In other words, the intra-pulse modulation specification detection unit 11 synchronizes the pulse data with intra-pulse modulation with the pulse waveform data stored in the memory 10, and outputs each pulse to the corresponding pulse waveform data. In-pulse modulation parameters are detected.
The synchronization can be achieved by using the same reference signal for sampling in the video signal A / D converter 4 and the IF signal A / D converter 9 so that the time can be matched. The original detection unit 11 can read the pulse waveform data at the same timing as the pulse data with intra-pulse modulation transmitted from the pulse separation unit 8 from the memory 10.

  The intra-pulse modulation specification result obtained by the intra-pulse modulation specification detection unit 11 is sent to the target data generation unit 12, and is matched with the pulse data obtained from the pulse train separation unit 8 to the target data generation unit 12 to be processed. Target data of the radar signal to be generated is generated. An example of the target data generation is shown in FIG. The target data generated in this way is compared with a radar data database stored in advance, and the source of the radar signal is identified.

  As in the first embodiment, the presence / absence of intra-pulse modulation is simply analyzed. As a result of the analysis, only the target pulse signal analyzed as having intra-pulse modulation can analyze the modulation scheme of intra-pulse modulation. In addition, the load of the intra-pulse modulation analysis processing can be reduced, and radar signal identification can be performed in real time.

Embodiment 2
Next, a radar signal identification apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing the configuration of the radar signal identification apparatus according to the second embodiment. Components identical or corresponding to those in FIG.
In the first embodiment, the simple analysis result of the intra-pulse modulation obtained by the intra-pulse modulation simple analysis unit 7 is sent to the pulse train separation unit 8 and added to the specifications of the pulse train separation. In this second embodiment, The simple analysis result of the intra-pulse modulation by the intra-pulse modulation simple analysis unit 7 is not sent to the pulse train separation unit 8. Therefore, the simple analysis result by the intra-pulse modulation simple analysis unit 7 is directly notified to the intra-pulse modulation specification detection unit 11, and the intra-pulse modulation specification detection unit 11 detects the pulse of the pulse train separation unit 8 in which intra-pulse modulation is present. The data is synchronized with the pulse waveform data stored in the memory 10, and information such as amplitude characteristics, frequency characteristics, phase characteristics, etc. of the intra-pulse modulation method of each pulse is detected for the corresponding pulse waveform data, and the target data The data is sent to the generation unit 12.

It is a block diagram which shows the structure of the radar signal identification device by Embodiment 1 of this invention. It is a flowchart which shows the process algorithm of the intra-pulse modulation | alteration simple analysis part of the radar signal identification device by Embodiment 1 of this invention. It is a figure for demonstrating the simple analysis of the presence or absence of the frequency modulation in a pulse by Embodiment 1 of this invention. It is a figure for demonstrating the simple analysis of the presence or absence of the intra-pulse phase modulation by Embodiment 1 of this invention. It is a figure for demonstrating the simple analysis of the presence or absence of the intra-pulse phase modulation by Embodiment 1 of this invention. It is a figure which shows an example of the target data generation by Embodiment 1 of this invention. It is a block diagram which shows the structure of the radar signal identification device by Embodiment 2 of this invention.

Explanation of symbols

1: antenna, 2: RF / IF converter,
3: detection unit, 4: video signal A / D conversion unit,
5: PW / PRI / PA measurement unit, 6: Frequency measurement unit,
7: In-pulse modulation simple analysis unit, 8: Pulse train separation unit,
9: IF signal A / D converter 10: Memory
11: In-pulse modulation specification detection unit, 12: Target data generation unit

Claims (8)

An antenna that receives radar signals and extracts high-frequency signals;
An RF / IF converter for converting a high-frequency signal extracted by the antenna into an intermediate frequency signal;
A first signal processing circuit that detects pulse specifications of each radar signal received by the antenna from the intermediate frequency signal converted by the RF / IF converter, and generates pulse data having a common tendency;
Each radar signal received by the antenna from the intermediate frequency signal converted by the RF / IF converter is converted into digital pulse waveform data and stored in a memory, and the specifications of the intra-pulse modulation of each radar signal are detected. A second signal processing circuit,
The presence / absence of intra-pulse modulation is analyzed from the pulse specifications detected by the first signal processing circuit, and when the analysis results in modulation, the second signal processing circuit determines the intra-pulse modulation specifications. In-pulse modulation simple analysis unit for performing detection processing,
And a radar having a target data generation unit that generates target data of the target radar from the pulse data obtained by the first signal processing circuit and the intra-pulse modulation information obtained by the second signal processing circuit Signal identification device.   The first signal processing circuit detects a middle frequency signal converted by the RF / IF converter and outputs a video signal, and a video signal A converts the video signal from the detector to a digital signal. A D / D converter, and a PW / PRI / PA measuring unit for detecting the pulse width, pulse repetition period, and pulse amplitude of each radar pulse from the video signal digitized by the A / D converter. A frequency measurement unit for measuring a frequency from the intermediate frequency signal from the RF / IF conversion unit, and a radar signal based on the specifications of the pulses obtained from the frequency measurement unit and the PW / PRI / PA measurement unit. The radar signal identification device according to claim 1, further comprising: a pulse train separation unit that separates corresponding pulse trains into groups of pulses having a common tendency.   The second signal processing circuit includes an IF signal A / D converter that converts an intermediate frequency signal from the RF / IF converter into a digital signal, and a pulse waveform of the digital signal converted by the IF signal A / D converter. Synchronize the memory to be stored as data and the pulse waveform data stored in this memory and the pulse data with intra-pulse modulation. The radar signal identification device according to claim 1, further comprising an in-pulse modulation specification detection unit for detection.   The radar according to claim 2, wherein the intra-pulse modulation simple analysis unit analyzes the modulation method of intra-pulse modulation from the frequency and amplitude information inside the pulse obtained by the frequency measurement unit and the PW / PRI / PA measurement unit. Signal identification device.   The pulse train separation unit has a common tendency based on the pulse information obtained by the frequency measurement unit and the PW / PRI / PA measurement unit, as well as the internal modulation information extracted by the intra-pulse modulation simple analysis unit. 3. The radar signal identification device according to claim 2, wherein the pulse train is separated for each group.   The intra-pulse modulation simple analysis unit detects the rate at which the frequency at each timing exceeds a certain line from the frequency information of each timing inside the pulse obtained by the frequency measurement unit. 3. The radar signal identification apparatus according to claim 2, wherein whether or not there is present is simply analyzed.   The intra-pulse modulation simple analysis unit uses the amplitude information at each timing inside the pulse obtained by the PW / PRI / PA measurement unit, when there is a sudden drop in level by a certain amount from the amplitude value at the previous timing. 3. The radar signal identification apparatus according to claim 2, wherein a simple analysis is made as to whether or not the intra-pulse modulation is a phase modulation by detecting the location.   In-pulse modulation simple analysis unit, from the frequency information of each timing inside the pulse obtained by the frequency measurement unit, by detecting the location when there is a sudden change by a certain amount from the previous timing frequency, 3. The radar signal identification apparatus according to claim 2, wherein simple analysis is performed to determine whether the intra-pulse modulation is phase modulation.

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