JP5206590B2 - Pulse modulation signal identification method, pulse modulation signal identification method, and pulse modulation signal identification device - Google Patents

Description

  The present invention relates to a pulse modulation signal identification method for identifying or identifying a pulse train (pulse modulation signal) of a radar signal used in a radar signal identification device for identifying a radar signal by separating a plurality of incoming radio waves for each radar signal, and The present invention relates to a pulse modulation signal identification method and a pulse modulation signal identification device.

  Conventionally, there is a radar signal identification device described in Patent Document 1, for example. FIG. 10 of Patent Document 1 is a circuit diagram showing a conventional radar signal identification device. In FIG. 10, 10 is an antenna, 11 is a detection circuit, 12 is a pulse analysis unit, 13 is a frequency measurement unit, 14 is an azimuth detection circuit, 15 is a pulse separation unit, and 16 is a pulse analysis unit. That is, in this conventional apparatus, a radio frequency signal (RF signal) received by the antenna 10 is envelope-detected by the detection circuit 11 and converted into a video signal. The pulse analyzer 12 detects the characteristics of each pulse included in the video signal. That is, a pulse amplitude PA (Pulse Amplitude), a pulse width PW (Pulse Width), and a pulse input signal TOA (Time Of Arrival) are detected. The RF signal is also input to a frequency measuring unit 13 including an IFM (Instantaneous Frequency Measurement) circuit, and a signal frequency (pulse frequency) in the pulse is detected as feature data of each pulse. Furthermore, the azimuth detection circuit 14 detects the azimuth from which the pulse modulation signal arrives, and outputs the azimuth signal (BRG) as feature data of the received pulse.

  Based on these feature data, the pulse separation unit 15 separates each pulse included in the received signal for each identification target. Here, the identification target means a radar signal included in the received signal. That is, when the received signal is composed of two or more types of radar signals, two types of pulse trains in the video signal are mixed. For this reason, the pulse separation unit 15 determines which radar signal each pulse belongs to, and separates it into a pulse train for each radar signal. As a result, characteristic data of each pulse constituting the identification target is obtained for each identification target. The characteristic data of each pulse detected in this way is converted into characteristic data of the radar signal by statistical processing or the like, and the received radar signal is identified. If the apparatus has a database that defines the relationship between the radar signal feature data and the radar transmitter, a matching search is performed by using the feature data detected in the database as a key. The radar transmitter that is the transmission source can be identified.

JP 2000-304849 A (FIG. 10 etc.) JP 58-164008 A

Digital Techniques for Wideband Receivers Second Edition, James Tsui, Artech House, 2001, p340-347

  However, conventionally, in the pulse modulation signal identification method and the pulse modulation signal identification method used in the radar signal identification device, the received RF signal is converted into an IF (intermediate frequency) signal or a baseband video signal, and the detected IF signal or When a radar signal is identified by a video pulse signal, multi-bit high-rate A / D conversion is performed, and feature data of the video pulse signal is detected using arithmetic processing such as FFT (Fast Fourier Transform). Therefore, there is a problem that it is necessary to perform a large amount of calculation processing at high speed in order to detect feature data.

  The present invention has been made to solve the above-described problems. By using the zero crossing of the video pulse signal as the feature data, the identification processing of the pulse modulation signal can be performed at high speed at a high performance. It is an object of the present invention to provide a novel pulse modulation signal identification method, pulse modulation signal identification method, and pulse modulation signal identification apparatus.

  The pulse modulation signal specifying method according to the invention of claim 1 separates a video pulse signal obtained by envelope detection of an incoming radio wave composed of a pulse modulation signal into predetermined bands, and the separated video pulse signal is A zero crossing point within a predetermined range is detected for each predetermined band, and the pulse train of the incoming radio wave is specified from the number of zero crossing points for each predetermined band.

  According to a second aspect of the present invention, there is provided a pulse modulation signal specifying method that separates a video pulse signal obtained by envelope detection of an incoming radio wave composed of a pulse modulation signal into predetermined bands, and the separated video pulse signal is A zero crossing point within a predetermined range is detected for each predetermined band, the zero crossing point for each predetermined band is encoded for each predetermined band, and the pulse train of the incoming radio wave is specified from the encoded zero crossing point value It is characterized by doing.

  According to a third aspect of the present invention, there is provided a pulse modulated signal identification method that separates video pulse signals obtained by envelope detection of a plurality of incoming radio waves composed of pulse modulated signals into predetermined bands, and the plurality of separated videos. A zero crossing point within a predetermined range is detected for each predetermined band of the pulse signal, and the pulse train of the plurality of incoming radio waves is obtained from the number of zero crossing points for each predetermined band and the frequency and arrival direction of the plurality of incoming radio waves. Separately, the pulse train for each of the plurality of incoming radio waves is identified.

  According to a fourth aspect of the present invention, there is provided a pulse modulated signal identification method that separates video pulse signals obtained by envelope detection of a plurality of incoming radio waves composed of pulse modulated signals into predetermined bands, and the plurality of separated videos. A zero crossing point within a predetermined range is detected for each predetermined band of the pulse signal, the zero crossing point for each predetermined band is encoded for each predetermined band, and the encoded zero crossing value and the plurality The pulse train of the plurality of incoming radio waves is separated from the frequency and direction of the incoming radio wave, and the pulse train for each of the plurality of incoming radio waves is identified.

  According to a fifth aspect of the present invention, there is provided a pulse modulated signal identification device comprising: an antenna unit that receives a plurality of incoming radio waves composed of pulse modulated signals; a frequency measuring unit that measures the frequency of incoming radio waves received by the antenna unit; An azimuth detecting unit for detecting an incoming azimuth of radio waves, a band pass filter group for separating video pulse signals obtained by envelope detection of incoming radio waves received by the antenna unit for each predetermined band, and the band pass filter group A zero-crossing detection unit group for detecting a zero-crossing point within a predetermined range for each of the predetermined bands, and the zero-crossing point for each of the predetermined bands detected by the zero-crossing detection unit group. A plurality of arrival frequencies of the plurality of incoming radio waves measured by the frequency measurement unit and the arrival directions of the plurality of incoming radio waves detected by the direction detection unit. Separating the pulse train of the radio wave, and is characterized in that identifying the pulse train for each of said plurality of incoming waves.

  According to a sixth aspect of the present invention, there is provided a pulse modulated signal identification device comprising: an antenna unit that receives a plurality of incoming radio waves composed of pulse modulated signals; a frequency measuring unit that measures the frequency of incoming radio waves received by the antenna unit; An azimuth detecting unit for detecting an incoming azimuth of radio waves, a band pass filter group for separating video pulse signals obtained by envelope detection of incoming radio waves received by the antenna unit for each predetermined band, and the band pass filter group A zero-crossing detection unit group for detecting a zero-crossing point within a predetermined range for each predetermined band of the video pulse signal separated from each other, and a zero-crossing point within a predetermined range detected by the zero-crossing detection unit group The coding processing unit group that encodes each band of the signal and the zero crossing point within the predetermined range encoded for each predetermined band encoded by the encoding processing unit group are integrated. And a plurality of arrivals measured by the frequency measurement unit, and the arrival radio waves encoded for each predetermined band at a zero-crossing point within a predetermined range integrated by the code integration processing unit. A pulse separation unit for separating the pulse train of the plurality of incoming radio waves from the frequency of the radio wave and the arrival directions of the plurality of incoming radio waves detected by the direction detection unit, and the pulse train of the plurality of incoming radio waves separated by the pulse separation unit And a pulse train analysis unit for analyzing the above.

  As described above, according to the present invention, a video pulse signal obtained by envelope detection of an incoming radio wave composed of a pulse modulation signal is decomposed into signals of each frequency band by a bandpass filter, and the signals of the respective frequency bands are A pulse modulation signal identification method, pulse modulation signal identification method, and pulse modulation signal identification device capable of improving the performance of the pulse identification and speeding up the processing by using the zero crossing point as the characteristic data of the received pulse. Can do.

1 is a block diagram of a pulse modulation signal identification device according to Embodiment 1 of the present invention. It is explanatory drawing about the pass band of the band pass filter group in the pulse modulation signal identification device which concerns on Embodiment 1 of this invention. It is operation | movement explanatory drawing of the band pass filter group in the pulse modulation signal identification device which concerns on Embodiment 1 of this invention. It is operation | movement explanatory drawing of the zero crossing detection part and encoding process part in the pulse modulation signal identification device which concerns on Embodiment 1 of this invention. It is operation | movement explanatory drawing of the zero crossing detection part and encoding process part in the pulse modulation signal identification device which concerns on Embodiment 2 of this invention. It is operation | movement explanatory drawing which integrates the encoded information in the pulse modulation signal identification device which concerns on Embodiment 2 of this invention. This is about the center of gravity according to the present invention. It is explanatory drawing of the hard limiter which concerns on this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes a radar signal emitted from a plurality of radars, and an antenna unit that receives a plurality of incoming radio waves composed of pulse-modulated signals. Reference numeral 2 denotes a frequency measurement unit that measures the frequency of the incoming radio waves received by the antenna unit 1. Reference numeral 3 denotes an azimuth detecting unit that detects the arrival direction of the incoming radio wave, 4 denotes a detection circuit that detects the incoming radio wave received by the antenna unit 1, and 5 denotes an incoming radio wave (video pulse signal) detected by the detection circuit 4. A band-pass filter group that separates for each predetermined band, and a zero-crossing detection unit group that detects a zero-crossing point within a predetermined range for each predetermined band of the video pulse signal of the incoming radio wave separated by the band-pass filter group 5 , 7 is an encoding processing unit group that encodes zero crossing points within a predetermined range detected by the zero crossing detection unit group 6 for each of the predetermined bands, and 8 is an encoding processing unit group 7 that is encoded. The code integration processing unit 9 integrates the zero crossing points within the range of the received radio wave and the frequency measurement unit 2, which encodes the zero crossing points within the predetermined range integrated by the code integration processing unit 8 for each predetermined band. A pulse separation unit that separates a plurality of pulse trains (pulse modulation signals) of the incoming radio waves from the frequencies of the incoming radio waves measured by, and the arrival azimuths of the plurality of incoming radio waves detected by the direction detection unit 3. Is a pulse train analysis unit that analyzes a plurality of pulse trains of incoming radio waves separated from each other. In the drawings, the same reference numerals indicate the same or corresponding parts.

  In FIG. 1, the pulse modulation signal identification device is replaced with a bandpass filter group 5, a zero-crossing detection unit group 6, a code, instead of the portion corresponding to the first pulse analysis unit 12 in FIG. It comprises an encoding processing unit group 7 and an encoding integration processing unit group 8. The bandpass filter group 5 is composed of n bandpass filters, bandpass filters 1 to n (n is an integer), and the zero-crossing detection unit group 6 and the encoding processing unit group 7 are shown in FIG. As described above, the zero-crossing detection units 1 to n and the encoding processing units 1 to n connected to the subsequent stages of the bandpass filters 1 to n are configured to correspond to the n bandpass filters on a one-to-one basis.

  In FIG. 1, the video pulse signal that is the output of the detection circuit 4 has a direct current component due to the rectification action in envelope detection, and is a positive or negative unipolar signal. Therefore, in general, the video pulse signal does not have a zero crossing in which the signal level crosses the zero level when the polarity is inverted from positive to negative or from negative to positive. Since the components are removed and AC components of predetermined bands are output, the video pulse signal has a zero crossing in which the signal level crosses the zero level when it is input to the zero crossing detection unit group 6.

  The characteristics of the video signal (pulse waveform) used for pulse separation and pulse train analysis in the conventional apparatus shown in Patent Document 1 are PW (pulse width) and PA (pulse amplitude) as shown in FIG. In the pulse modulated signal identification device according to the present invention, the zero crossing characteristics (the number of zero crossings per band and the zero crossing per band) are reflected in the pulse modulated signal identification device according to the present invention. Position) is used as a pulse feature. The pulse separation unit 9 and the pulse train analysis unit 10 separate the pulses using this zero crossing characteristic as a feature of the pulse, and analyze the pulse train. Since the performance of pulse separation and pulse train analysis can be expected to be higher when the characteristics of the pulses used are more diverse, in the pulse modulation signal identification device according to the present invention, in addition to the zero-crossing characteristics, PW and PA used can also be used in combination.

  Next, the operation of the pulse modulation signal identification apparatus according to the first embodiment will be described with reference to FIGS. In FIG. 1, an antenna unit 1 receives a plurality of incoming radio waves that are radar signals emitted from a plurality of radars and are composed of pulse modulation signals, and outputs an RF signal to a detection circuit 4. The detection circuit 4 detects the input RF signal by envelope detection and generates a video pulse signal. The video pulse signals are output to band pass filters 1, 2, 3,... N (band pass filter group 5) having different pass bands, and the input video pulse signals are separated into signals of respective frequency bands. FIG. 2 is an explanatory diagram of the passband of the bandpass filter group 5 of the pulse modulated signal identification device according to Embodiment 1 shown in FIG. The passband of each bandpass filter is assigned a frequency according to the number of bandpass filters from the frequency band of the received signal. When the number of band-pass filters is n as shown in FIG. 2A, the frequency band of the received signal is assigned in the range of n. When the number of band-pass filters is three as shown in FIG. 2B, the frequency band of the received signal is assigned in the range of three.

  In FIG. 2, the passband width of the entire bandpass filter group 5 is matched to the bandwidth of the received signal. There are two ways to adjust the bandwidth of the received signal, and it is adjusted according to the situation of incoming radio waves and the purpose of pulse separation and pulse train analysis.

  The first method is that the pulse width of the incoming radio wave ranges widely from, for example, a short pulse of 0.1 microsecond to a long pulse of several tens of microseconds, and the pulse width is one of the main features of pulse separation and pulse train. This is a method of matching in the case of performing analysis, and the passband width of the entire bandpass filter group 5 is determined by calculating the effective bandwidth (short pulse width) of the signal to be received by the pulse modulation signal identification device (the shortest pulse width). The bandwidth is adjusted to 2 to 3 times the half power width.

  The second method is that the pulse width of the signal to be received by the pulse modulation signal identification device is limited to the same level, and the main feature is the fine fluctuation of the video pulse signal waveform rather than the pulse width. This is a combination method in the case of performing separation and pulse train analysis. The entire pass band width of the band-pass filter group 5 is defined as the bandwidth of the signal having this pulse width, that is, the effective bandwidth corresponding to the reciprocal of this pulse width (power The bandwidth is adjusted to 2 to 3 times the half width.

  Further, as the number n of the bandpass filters shown in FIG. 2 is larger, the pulse separation and the pulse train analysis can be performed with higher accuracy. However, if the multipath wave superimposed on the incoming radio wave is strong, the distortion of the video pulse signal waveform due to this is strong. If the incoming radio wave is weak, it is easily affected by receiver noise. Further, since the circuit scale increases, n = 3 to 4 is practically used.

The passbands of the bandpass filters 1, 2, 3,... N are assigned according to the passband of the entire bandpass filter group 5 and the number of bandpass filters n. Practically, for example, the bandwidths of the respective bands are made equal or the bandwidths of the respective bands are increased at an equal ratio in order from the low frequency side to the high frequency side. The value of the equal ratio is determined by the balance between the bandwidth value of the lowest bandpass filter 1, the passband width of the entire bandpass filter group 5 and the number n of bandpass filters. For example, practically, the second method of adjusting the passband width of the entire bandpass filter group 5 to the bandwidth of the received signal is used. When n = 3, the bandwidth of the bandpass filter 1 is 1 / of the effective bandwidth (half-power width) equivalent to the reciprocal of the pulse width of the signal
√2 and the ratio value is √2. Whether to equalize the bandwidth of each band or increase it by an equal ratio is determined in consideration of the pros and cons of each. When the first matching method is used, it is practical to make the ratio equal since the pass band width of the entire band-pass filter group 5 is generally wide.

  Further, in the bandpass filter group 5 shown in FIG. 2, the crossover frequency of each adjacent bandpass filter is, for example, a frequency at which the gain (passage loss) of each bandpass filter is −3 dB (power is half value). . In the lowest bandpass filter 1, the gain (passage loss) at zero frequency (DC) is set to, for example, −3 dB (power is half value) to provide DC blocking characteristics.

  FIG. 3 is an explanatory diagram of the operation when the number of band-pass filter groups 5 of the pulse modulation signal identification apparatus according to Embodiment 1 shown in FIG. 1 is three. That is, it is the state of the band pass filter group 5 described in FIG. Video pulse signals obtained by envelope detection by the detection circuit 4 are input to the respective bandpass filters 1, 2 and 3. Then, the input video pulse signal is converted into a video pulse signal formed by the respective passband components, and is output to the corresponding zero-crossing detectors 1, 2, and 3. The operation of the zero-crossing detection unit group 6 is a circuit that detects a signal when the amplitude of the signal becomes 0, as shown in Patent Document 2, for example. The range for detecting the zero crossing point is a range wider than the PW of the video pulse signal input to the band pass filter group 5 in order to detect the zero crossing point of the video signal converted by the band pass filter having the lowest pass band. The detection range of the intersection. In the first embodiment, as shown in FIG. 3, a range twice as large as PW is set as a detection range of the zero crossing.

  Also, the time axis position of the detection range of the zero crossing point, that is, the detection start time and the detection end time are respectively before the pulse rising edge and after the pulse falling edge of the video pulse signal, and the center of the zero crossing detection range is aligned with the center of the video pulse signal. . The zero-crossing detection range of each band of the zero-crossing detection unit group 6 is the same, the center of the detection range and the center of the video pulse signal are approximately matched, and the difference is practically within about 10% of PW, for example. The center of the video pulse signal is approximately the center of the pulse waveform, for example, the center of the pulse falling and the pulse falling, or the center of gravity of the horizontal axis of the pulse waveform as shown in FIG. The encoding processing units 1, 2, and 3 encode (numerize) the number of zero crossing points detected by the zero crossing detection unit 6 as shown in FIG. 4, and the code integration processing unit 8 integrates the codes of the respective bands. The feature data of the received pulse signal is used, and using this feature data, the pulse separator 9 identifies and separates pulses having the same feature data from a plurality of incoming radio waves (radar signals).

  The center of gravity is a first moment of the area surrounded by the time axis and the waveform or function. As shown in FIG. 7, the center of gravity includes the center of gravity of the horizontal axis and the center of gravity of both the vertical and horizontal axes. The center of gravity on the horizontal axis is a line perpendicular to the horizontal axis in which the left and right areas of the center of gravity are equal. On the other hand, the center of gravity of both vertical and horizontal axes means that when a line is drawn perpendicular to the horizontal axis so as to pass through the center of gravity, the left and right areas of the line become equal, and the line perpendicular to the vertical axis passes through the center of gravity. This is the point where the area above and below the line becomes equal when subtracting. The center of gravity of the horizontal axis is the area center of gravity (one-dimensional moment), and the center of gravity of both the vertical and horizontal axes is the area center of gravity (two-dimensional moment). When the area centroid is simply used, it includes both the area centroid (one-dimensional moment) and the area centroid (two-dimensional moment). Further, the moment represents the first moment unless the order is specified.

  Specifically, in FIG. 3, the bandpass filter group 5 is composed of three bandpass filters 1, 2, and 3, and the outputs of the zeropass detection units 1, 2, 2, 3 detects a zero crossing. The waveform from the bandpass filter 1 has two zero crossings. The waveform from the bandpass filter 2 has 8 zero crossings. The waveform from the bandpass filter 3 has 14 zero crossings. The encoding processing units 1, 2, and 3 encode (numerize) the numbers of zero crossings 2, 8, and 14 to 02, 08, and 14, respectively, and the code integration processing unit 8 integrates these codes. Therefore, the characteristic data of the received pulse is (02, 08, 14).

  The pulse separation unit 9 separates pulses having the same feature data from the feature data of the plurality of received pulses, and outputs a pulse train having the same feature data to the pulse train analysis unit. The criteria for determining that the feature data is the same for the pulse separation unit 9 are that the codes (numerical values) representing the number of zero crossings are the same for each band, or the difference is equal to or less than a predetermined threshold value. The predetermined threshold is 1 as the minimum. For example, in the case of FIG. 4, if the code (numerical value) is 02 ± 1, 08 ± 1, 14 ± 1 for each band, it is determined that the features are the same. The maximum of the predetermined threshold is set to a value according to the ease of determination. For example, if the sign (numerical value) is 02 ± 1, 08 ± 2, or 14 ± 4, the characteristic is the same as the characteristic.

By performing such processing, the incoming radio wave composed of the pulse modulation signal is separated for each predetermined band, the separated incoming radio wave is detected for a zero crossing point within a predetermined range for each predetermined band, It is possible to identify the pulse train of the incoming radio wave from the number of zero crossings for each predetermined band. Further, if a pulse train for each of a plurality of incoming radio waves is specified in advance, each can be identified.

Embodiment 2. FIG.
In the first embodiment, the feature data of the received pulse signal is the number of zero crossings. However, in this embodiment, in order to improve the accuracy of pulse identification and separation, the zero crossing position is added as feature data in addition to the number of zero crossings. In addition, the encoding processing unit group 7 and the code integration processing unit 8 process the zero crossing position information.

  The block diagram of the pulse modulation signal identification device according to the second embodiment is the same as the block diagram according to the first embodiment of FIG. 1, but in the second embodiment, the encoding processing unit group 7 and the code integration are the same. The operation of the processing unit 8 is different from that of the first embodiment. FIG. 5 is a diagram for explaining the operation of the encoding processing unit group 7 of the pulse modulation signal identification apparatus according to the second embodiment, and FIG. 6 is a diagram for explaining the operation of the code integration processing unit 8 according to the present embodiment. The operations of the encoding processing unit group 7 and the code integration processing unit 8 according to the second embodiment will be described with reference to FIGS.

  FIG. 5 shows the detection of the zero crossing by the zero crossing detection units 1, 2, and 3 from the video signals output from the bandpass filters 1, 2, and 3 shown in FIG. It is a figure explaining operation | movement of the encoding process part group 7 to process. As an example, the input signal is the output of the bandpass filter 2 of the bandpass filter group 5 shown in FIG. The operation of encoding the signals output from the zero-crossing detection unit group 6 divides the zero-crossing detection range into an arbitrary number of time cells, and if there is a zero-crossing point in the time cell, the signal is “1”. When there is no zero crossing point, the signal is coded as “0” in binary. In FIG. 5, the number of time cells is 16 as an example. Although the zero-crossing detection range as a time width changes according to the PW of the received pulse, the number of time cells in the zero-crossing detection time range is set to a predetermined fixed value by normalizing the time cell width with PW. Even a pulse having a different PW can be encoded with a predetermined number of time cells.

  The above-described encoded binary information is integrated in the order of predetermined code information as shown in FIG. 6 and used as characteristic data of the received pulse signal. In FIG. 6, the encoded information 1, 2, and 3 correspond to the video signals output by the bandpass filters 1, 2, and 3, respectively. In this way, the zero crossing position information, which is a fine feature of the waveform of the received video pulse signal of the radar, is encoded, and the information obtained by integrating the encoded information is used as the feature data of the received pulse signal. Identify and separate pulse signals with high accuracy.

  The pulse separation unit 9 separates pulses having the same feature data from the feature data of the plurality of received pulses, and outputs a pulse train having the same feature data to the pulse train analysis unit. In the second embodiment, whether or not a plurality of received pulses have the same feature data in the pulse separation unit 9 is obtained by using the encoding information 1, 2, and 3 shown in FIG. A match is checked, and the number of matching values is compared with a predetermined threshold value to determine. For example, in FIG. 6, encoding information 2 has 8 bit values 1 out of 16 bits, and the positions thereof are the first, second, third, fifth, seventh, eleventh, thirteenth and sixteenth bit positions from the highest. Yes, there are 8 bit values 0, and their positions are the fourth, sixth, eighth, ninth, tenth, twelfth, fourteenth, and fifteenth bit positions in order from the top. If the bit position of the bit value 1 and the bit position of the bit value 0 of the encoded information 2 are all the same bit position among the plurality of received pulses, the number of coincidence of the bit values for each bit is 16. If there are, for example, 4 bits out of 16 bits whose bit values do not match, the number of matching values for each bit is 12. If, for example, the predetermined threshold value for the number of coincidence of bit values is 14 and the number of coincidence of bit values for each bit is 16, it is determined that the two received pulses have the same feature data for encoded information 2 To do. If the number of matches is 12, it is determined that they do not have the same feature data.

  For example, when the determination is strictly performed, the predetermined threshold value is 16 or 14 considering the quantization error ± 1 at the zero crossing position caused by the time cell width. In the case where the determination is made gently considering that the zero-crossing position changes due to the influence of receiver noise and multipath waves, the predetermined threshold value is set to a smaller value, for example, twelve. The same determination is made for the encoded information 1 and 3.

  As described above, in the pulse modulation signal identification apparatus according to Embodiments 1 and 2, the pulse separation unit 9 uses the zero-crossing detection information (the number of intersections and the intersection position) of the video pulse signal as feature data, and receives a plurality of received pulses. Pulses having the same feature data are identified and separated from each feature data. In the pulse separation unit 9, the signal frequency (pulse frequency), direction (BRG), pulse amplitude PA, and pulse width PW in the pulse used for pulse identification and separation are used as feature data by the conventional radar signal identification device as feature data. Is also possible. In the pulse modulation signal identification device according to the present invention, in addition to the conventional feature data, the zero crossing characteristics (the number of zero crossings and the zero crossing position for each band) are used as the pulse characteristics, so that the pulse identification and separation performance is further improved. improves.

  The pulse modulation signal identification device according to the first and second embodiments uses analog filters for the bandpass filters 1 to n that separate the incoming radio waves (video pulse signals) detected by the detection circuit 4 into predetermined bands. It was. Subsequent zero crossing detectors 1 to n convert analog AC signals, which are output signals of the bandpass filters 1 to n, into square pulses using, for example, a hard limiter as shown in FIG. An analog signal processing circuit configuration that detects the zero crossing at the rising and falling edges of the square pulse is adopted. Therefore, all the signal processing of the bandpass filter group 5 and the zero crossing detection unit group 6 is analog processing, and high-speed and real-time processing is possible.

  However, if the bandpass filters 1 to n are analog filters, it is difficult in terms of circuit scale and cost to configure a bandpass filter group that can adaptively change the passband width for each received signal. In such a case, the band-pass filter group 5 and the zero crossing detection unit group 6 can be configured by digital signal processing circuits. In order to obtain a digital circuit configuration, an A / D converter that converts a video pulse signal into digital data is provided at the subsequent stage of the detection circuit 4, and the bandpass filter group 6 is configured by a digital filter. Alternatively, although the processing speed is reduced, instead of the digital filter, FFT (Fast Fourier Transform) is performed by the CPU, and only a required passband component is extracted from the result, and inverse FFT is performed to return to the time waveform data. Also good. The zero-crossing detection unit group may detect the time at which the sign of the waveform data is inverted using the time waveform data.

  The characteristics of the hard limiter shown in FIG. 8 are ideal characteristics. Although the characteristics of the hard limiter configured by the analog circuit actually used are slight, they are deviated from the ideal characteristics. It has the characteristics of a smooth limiter similar to a tangent function. Instead of a hard limiter configured by an analog circuit as the hard limiting means, amplitude limiting processing (hard limiting processing) may be performed by digital calculation. When the amplitude limiting process is performed by digital calculation, the amplitude limiting process is performed on the digital data of the received signal waveform that has been A / D converted by the A / D converter. When the amplitude limiting process is performed by digital computation, for example, a process of outputting a digital value of +1 if the sign is positive and a digital value of -1 if the sign is negative according to the sign of the digital data of the received signal waveform Just do it. By providing the hard limiting means, even if the S / N ratio is small, if the signal power exceeds the noise power, the noise is suppressed by the small signal suppression effect in the hard limiting. Since the symmetry is improved and the occurrence of a plurality of peaks is suppressed, the calculated position deviation of the center of gravity is reduced, and an azimuth detecting device or direction detecting method with improved accuracy can be obtained.

  When the pulse modulation signal identification device according to the present invention is configured as the digital circuit and the FFT is performed using the CPU, for example, the signal processing becomes non-real time processing and the processing speed is reduced, but the data handled in the digital signal processing is the base A / D conversion data of a video pulse signal in a band. As shown in FIG. 12 of Patent Document 1, in a conventional apparatus, an IF signal having a frequency much higher than that of a baseband is generally A / D and digital signal processing is performed. It is sufficient to handle a smaller amount of data, and it is easier to ensure high-speed signal processing as compared with conventional devices.

  In addition, with a digital circuit configuration, multi-bit high-rate A / D is required to ensure zero-crossing detection accuracy. For example, FFT and inverse FFT processing time is further required, and high-speed processing performance is degraded. In such a case, in order to prevent any deterioration in the high-speed processing performance, high detection accuracy may be obtained by estimating the zero-crossing position at high speed by a simple calculation method instead of using a high rate. A simple calculation method is shown in FIGS. 10.5 and 10.6 of Non-Patent Document 1, for example.

1 .. Antenna unit 2. Frequency measuring unit 3. Direction detection unit 4. Detection circuit 5. Band pass filter group 6. Zero cross detection unit group 7. Encoding processing unit Group, 8... Code integration processing unit, 9... Pulse separation unit, 10.

Claims (6)

  A video pulse signal obtained by envelope detection of an incoming radio wave composed of a pulse modulated signal is separated for each predetermined band, and the separated video pulse signal is detected for a zero crossing point within a predetermined range for each predetermined band. And a pulse modulation signal specifying method, wherein the pulse train of the incoming radio wave is specified from the number of zero crossing points for each of the predetermined bands.   A video pulse signal obtained by envelope detection of an incoming radio wave composed of a pulse modulated signal is separated for each predetermined band, and the separated video pulse signal is detected for a zero crossing point within a predetermined range for each predetermined band. A method for identifying a pulse modulation signal, comprising: encoding a zero crossing point for each predetermined band for each predetermined band; and specifying the pulse train of the incoming radio wave from the encoded zero crossing point value.   A video pulse signal obtained by envelope detection of a plurality of incoming radio waves composed of a pulse modulation signal is separated for each predetermined band, and the separated video pulse signals are within a predetermined range for each predetermined band. Detecting zero-crossings, separating the pulse trains of the plurality of incoming radio waves from the number of zero-crossings for each predetermined band and the frequencies and azimuths of the plurality of incoming radio waves, and identifying the pulse trains for the plurality of incoming radio waves A method for identifying a pulse modulated signal.   A video pulse signal obtained by envelope detection of a plurality of incoming radio waves composed of a pulse modulation signal is separated for each predetermined band, and the separated video pulse signals are within a predetermined range for each predetermined band. A zero-crossing point is detected, the zero-crossing points for each of the predetermined bands are encoded for each of the predetermined bands, and the plurality of incoming radio waves are determined from the encoded zero-crossing point values and the frequencies and arrival directions of the plurality of incoming radio waves. And identifying a pulse train for each of the plurality of incoming radio waves.   An antenna unit that receives a plurality of incoming radio waves composed of pulse-modulated signals, a frequency measurement unit that measures the frequency of incoming radio waves received by the antenna unit, an azimuth detection unit that detects the arrival direction of the incoming radio wave, and the antenna A band-pass filter group that separates a video pulse signal obtained by envelope detection of incoming radio waves received by the unit for each predetermined band, and the video pulse signal separated by the band-pass filter group for each predetermined band A zero-crossing detection unit group for detecting zero-crossing points within a predetermined range, and the number of zero-crossing points for each predetermined band detected by the zero-crossing detection unit group and the plurality of incoming radio waves measured by the frequency measurement unit And separating the pulse train of the plurality of incoming radio waves from the frequency and the arrival azimuth of the plurality of incoming radio waves detected by the azimuth detecting unit. Identifying a pulse train with pulse modulation signal identifying apparatus according to claim.   An antenna unit that receives a plurality of incoming radio waves composed of pulse-modulated signals, a frequency measurement unit that measures the frequency of incoming radio waves received by the antenna unit, an azimuth detection unit that detects the arrival direction of the incoming radio wave, and the antenna A band-pass filter group that separates a video pulse signal obtained by envelope detection of incoming radio waves received by the unit for each predetermined band, and the video pulse signal separated by the band-pass filter group for each predetermined band A zero-crossing detection unit group for detecting a zero-crossing point within a predetermined range; and an encoding processing unit group for encoding the zero-crossing point within a predetermined range detected by the zero-crossing detection unit group for each predetermined band; A code integration processing unit that integrates zero crossing points within a predetermined range encoded for each of the predetermined bands encoded by the encoding processing unit group, and the code integration processing unit The incoming radio waves that are encoded for each predetermined band of the zero crossing points within the combined predetermined range, the frequencies of the multiple incoming radio waves measured by the frequency measurement unit, and the plurality of detections detected by the direction detection unit A pulse separation unit that separates the pulse trains of the plurality of incoming radio waves from the arrival direction of the incoming radio waves, and a pulse train analysis unit that analyzes the pulse trains of the plurality of incoming radio waves separated by the pulse separation unit A pulse modulation signal identification device.

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