Multi-tone radar and transmission / reception method

Abstract

This multi-tone radar (100) transmits a multi-tone signal as a radar signal and an interference signal interfering with a threat radar wave, and receives, as an echo signal, a multi-tone signal including a radar signal reflected by a target. The multi-tone radar (100) is provided with a plurality of division circuits (#1 to #n) for transmitting multi-tone signals respectively in a plurality of frequency ranges obtained by dividing the transmission / reception frequency range of the multi-tone radar (100). The plurality of division circuits (#1 to #n) include a division circuit for radar, which transmits the multi-tone signal as a radar signal, and a division circuit for interference, which transmits the multi-tone signal as an interference signal.

Description

Multi-tone radar and transmission / reception method

[0001] The present disclosure relates to multi-tone radar and transmission and reception methods.

[0002] In recent years, improvements in the performance of digital components have led to the widening of the bandwidth of radar and EW (Electronic Warfare) equipment. Generally, radar and EW equipment are developed separately, so when radar and EW equipment are installed on an aircraft, for example, the overall avionics hardware becomes large in size, and a device to integrate them is also required.

[0003] For example, Patent Document 1 discloses a wideband radar device that includes a transmitter that transmits a wideband signal and a receiver that receives a reflected wave of the wideband signal transmitted from the transmitter, and that detects a target based on the result of bandwidth synthesis of a plurality of subband signals having different frequency bands in the reflected wave received by the receiver, excluding subband signals that have interference.

[0004] JP 2009-8452 A

[0005] The wideband radar device disclosed in Patent Document 1 is a device for removing unwanted waves and does not have the function of transmitting jamming waves. Therefore, in order to use this wideband radar device to jam a wideband threat radar, another EW device that transmits jamming waves in a wideband and a device that integrates these are required, which increases the scale of the hardware.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to broaden the bandwidth of radar and EW devices while suppressing an increase in the scale of hardware.

[0007] To achieve the above object, a multi-tone radar according to the present disclosure transmits a multi-tone signal as a jamming signal and a radar signal that jams a threat radar wave, and receives a multi-tone signal including a radar signal reflected from a target as an echo signal. The multi-tone radar includes a plurality of dividing circuits. The plurality of dividing circuits transmit multi-tone signals in a plurality of frequency ranges obtained by dividing the transmission and reception frequency range of the multi-tone radar. The plurality of dividing circuits includes a radar dividing circuit that transmits the multi-tone signal as a radar signal and a jamming dividing circuit that transmits the multi-tone signal as a jamming signal.

[0008] According to the present disclosure, by providing a dividing circuit corresponding to multiple frequency ranges obtained by dividing the transmission and reception frequency range of a multi-tone radar, and the multiple dividing circuits including a dividing circuit for the radar and a dividing circuit for jamming, it is possible to make the radar and EW device broadband and suppress an increase in the size of the hardware.

[0009] FIG. 1 is a diagram showing a configuration example of a multi-tone radar according to the first embodiment. FIG. 2 is a diagram showing the frequency range of a wideband BPF according to the first embodiment. FIG. 3 is a diagram showing the frequency range of a narrowband BPF according to the first embodiment. FIG. 4 is a diagram showing hopping of a radar signal in a multi-tone radar according to the first embodiment. FIG. 5 is a diagram showing a configuration example of an integrated processing circuit according to the first embodiment. FIG. 6 is a diagram showing the ECCM effect of a multi-tone radar according to the first embodiment.

[0010] A multi-tone radar according to this embodiment will be described in detail below with reference to the drawings. Note that identical or corresponding parts in the drawings are designated by the same reference numerals, and their descriptions will not be repeated in principle. A multi-tone radar is a radar that transmits a multi-tone signal as a radar signal, receives a multi-tone signal including a radar signal reflected from a target as an echo signal, and detects the target based on the echo signal. Here, a multi-tone signal refers to the simultaneous transmission of multiple signals. The opposite of a multi-tone signal is a multi-spot signal, which refers to the instantaneous transmission of a single wave.

[0011] (Embodiment 1) Fig. 1 shows an example configuration of a multi-tone radar 100 according to embodiment 1. The multi-tone radar 100 has a configuration in which a plurality of wideband RF (Radio Frequency) circuits are arranged to divide the transmission and reception frequency range in order to provide a transmission and reception band that is sufficiently wider than the transmission and reception bandwidth of the ECM device. Hereinafter, among the wideband RF circuits obtained by dividing the frequency range of the multi-tone radar 100, the RF circuit of the transmission system is referred to as a divided circuit (transmission), and the RF circuit of the reception system is referred to as a divided circuit (reception). Furthermore, the divided circuit (transmission) and the divided circuit (reception) are collectively referred to simply as a divided circuit.

[0012] The multi-tone radar 100 transmits a multi-tone signal as a radar signal and receives a multi-tone signal including a radar signal reflected from a target as an echo signal. To achieve a high ECCM effect, the multi-tone radar 100 assigns one multi-tone signal to each division circuit for transmission and reception, and extracts and employs only target detection results that are not affected by threatening jamming signals from the target detection results processed by each division circuit. Furthermore, the multi-tone radar 100 hops or agiles each multi-tone signal to improve the ECCM effect. In the figure, straight arrows represent analog signals (RF signals / IF signals), and dashed arrows represent digital signals (data).

[0013] First, the reception system of the multi-tone radar 100 will be described. The echo signal received by the aerial 11, which serves as an antenna, passes through a duplexer 12 and is amplified by an amplifier 13. The amplified echo signal is limited to a set frequency band and band by a filter bank 14, which determines the transmission and reception bands of the multi-tone radar 100, and is frequency-converted to a 1st IF (Intermediate Frequency) signal by a mixer 15 using a 1st Lo signal. The 1st IF signal output from the mixer 15 is distributed to division circuits (reception) #1 to #n by a divider 16. In the figure, division circuits (reception) #1 to #n are denoted as #1 (reception) to #n (reception), respectively. n is the number of divisions, or the number of multi-tone signals. Hereinafter, each multi-tone signal will be referred to as multi-tone signals #1 to #n, and the division circuits corresponding to multi-tone signals #1 to #n will be referred to as division circuits #1 to #n. The 1st IF signal is an example of a first intermediate frequency signal.

[0014] After distribution, the 1st IF signal is band-limited by BPFs (wide) 171 to 17n for each division circuit (reception). Hereinafter, BPFs (wide) 171 to 17n are collectively referred to as BPF (wide) 17. The band limited by BPF (wide) 17 is a wide bandwidth that defines the hopping range and agile range for each wave of the multi-tone signal.

[0015] The frequency ranges of the BPFs (wide) 171 to 17n will be described using FIG. 2. As shown in FIG. 2, the transmission and reception frequency range of the multi-tone radar 100 is divided into frequency ranges of the BPFs (wide) 171 to 17n corresponding to the division circuits #1 to #n. The frequency ranges of the BPFs (wide) 171 to 17n are the hopping range and agile range of the multi-tone signals #1 to #n, respectively, and do not overlap with the bands of other division circuits. Specifically, the frequency separation between adjacent BPFs (wide) 17 is set to be 1.0 / τ [Hz] or greater, where τ is the pulse width of the radar signal (echo signal). This prevents the influence of spectrum broadening at the band edges of adjacent division circuits. Note that the set frequency separation may be sufficiently large if the characteristics of the components cause the influence of spectrum broadening at the band edges of adjacent division circuits, or if interference with other communication devices needs to be avoided.

[0016] As shown in Figure 1, the first IF signal, which is band-limited by BPFs (wide) 171 to 17n for each division circuit (reception), is frequency-converted to a second IF signal by mixers 181 to 18n using a second Lo signal. The second IF signal output from the mixers 181 to 18n is band-limited by BPFs (narrow) 191 to 19n, which define the instantaneous reception band of the radar. The second IF signal is an example of a second intermediate frequency signal.

[0017] The frequency range of the BPFs (narrow) 191 to 19n will be explained using FIG. 3. As shown in FIG. 3, the frequency range of the BPFs (narrow) 191 to 19n corresponding to the division circuits #1 to #n is a narrow band equivalent to the chirp width and matched filter. By controlling the second Lo frequency for each division circuit, hopping and agile frequency change is possible within the range of the BPFs (wide) 171 to 17n.

[0018] 1, the second IF signals that have passed through the narrow BPFs 191 to 19n are A-D converted by A-D converters 201 to 20n and output to signal processing circuits 211 to 21n. Based on the A-D converted signals, the signal processing circuits 211 to 21n perform signal processing to detect targets, and target detection data #1 to #n indicating the target detection results are output to the integrated processing circuit 22. The processing performed by the integrated processing circuit 22 will be described later.

[0019] Next, the transmission system of the multi-tone radar 100 will be described. When radar waveform data is output from the integrated processing circuit 22, it is converted from digital to analog by a digital-to-analog converter 23, and a second IF signal is output. Examples of radar waveform data include chirp, Barker code, FMCW (Frequency Modulated Continuous Wave), and pulse. The second IF signal output from the digital-to-analog converter 23 is distributed to division circuits (transmission) #1 to #n by a distributor 24. In the figure, division circuits (transmission) #1 to #n are represented as #1 (transmission) to #n (transmission), respectively. The distributed second IF signal is band-limited by narrow bandpass filters (BPFs) 251 to 25n. The narrow bandpass filters (BPFs) 251 to 25n of the transmission system are the same as the narrow bandpass filters (BPFs) 191 to 19n of the reception system.

[0020] The second IF signals that have passed through the narrow BPFs 251 to 25n are frequency converted to first IF signals by the mixers 261 to 26n using the second Lo signal, and then band-limited by the wide BPFs 271 to 27n. The wide BPFs 271 to 27n of the transmission system are the same as the wide BPFs 171 to 17n of the reception system. Hereinafter, the wide BPFs 271 to 27n will be collectively referred to as the wide BPFs 27.

[0021] The 1st IF signals that have passed through the BPFs (wide) 271 to 27n are combined by a combiner 28 to become a multi-tone signal, and then a mixer 29 uses the 1st Lo signal to frequency convert the signal to an RF signal. The RF signal is limited to a set frequency band and band by a filter bank 30 that determines the transmission and reception bands of the multi-tone radar 100, and then amplified by an amplifier 31. The amplified RF signal is transmitted as a radar signal from the antenna 11 via a duplexer 12. The filter bank 30 of the transmission system is the same as the filter bank 14 of the reception system. The duplexer 12 switches the antenna 11 between transmission and reception.

[0022] Here, the signal generating circuit will be described. The multi-tone radar 100 has and controls a first signal generating circuit 32 and second signal generating circuits 341 to 34n. n is the number of divisions, or the number of multi-tone signals. The first signal generating circuit 32 is a circuit that generates a 1st Lo signal for frequency conversion in the multi-tone radar 100. The 1st Lo signal generated by the first signal generating circuit 32 is distributed by a distributor 33 and input to the mixer 15 of the receiving system and the mixer 29 of the transmitting system. Since the 1st Lo signal generated by the first signal generating circuit 32 is a local signal common to each multi-tone signal (each division circuit), the tuning frequency falls within the transmission and reception frequency range of the multi-tone radar 100. In other words, the transmission and reception frequency range of the multi-tone radar 100 is defined by the 1st Lo signal. The 1st Lo signal is an example of a first local signal. The mixer 15 in the receiving system and the mixer 29 in the transmitting system are examples of mixers that are common to a plurality of dividing circuits.

[0023] The second signal generating circuits 341 to 34n are circuits that generate second Lo signals #1 to #n in the frequency conversion of the multi-tone radar 100. The second Lo signals #1 to #n generated by the second signal generating circuits 341 to 34n are distributed by distributors 351 to 35n, respectively, and input to the mixers 181 to 18n of the receiving system and the mixers 261 to 26n of the transmitting system. The second Lo signals #1 to #n generated by the second signal generating circuits 341 to 34n are local signals individual to each multi-tone signal (each dividing circuit), and therefore the second Lo signals #1 to #n define which frequency range the corresponding dividing circuit corresponds to within the divided frequency range of the transmission and reception frequency range of the multi-tone radar 100. The second Lo signals are an example of second local signals. The mixers 181 to 18n in the receiving system and the mixers 261 to 26n in the transmitting system are examples of individual mixers for each of the multiple division circuits.

[0024] In this embodiment, by individually controlling the second Lo frequency for each divided circuit, a frequency range obtained by dividing the transmission / reception frequency range of the multi-tone radar 100 is assigned to each divided circuit, and the second IF frequencies of all divided circuits are set to the same frequency range. As a result, the AD converters 201 to 20n and the DA converter 23 can have the same performance for each divided circuit, eliminating the need for a high sampling frequency. This makes it possible to achieve a wide bandwidth using conventional components.

[0025] Here, the hopping and agile of the multi-tone signal performed by the multi-tone radar 100 will be described. It is possible to hop or agile each multi-tone signal by varying the 1st Lo signal generated by the first signal generation circuit 32. Setting hopping or agile for the multi-tone signal reduces the influence of threatening jamming waves and achieves a high ECCM effect. However, because the 1st Lo signal generated by the first signal generation circuit 32 is a local signal common to each multi-tone signal, the frequency fluctuations due to hopping and agile of each multi-tone signal are the same.

[0026] On the other hand, it is also possible to individually hop or agile each multi-tone signal by varying the second Lo signals #1 to #n generated by the second signal generating circuits 341 to 34n. In this case, compared to using the first Lo signal generated by the first signal generating circuit 32 for hopping and agile, it is possible to individually control the frequency variation of each multi-tone signal, and therefore, from the perspective of improving ECCM performance, it is more effective to implement hopping and agile by varying the second Lo signals #1 to #n generated by the second signal generating circuits 341 to 34n. Therefore, in this embodiment, the multi-tone radar 100 implements hopping and agile by varying the second Lo signals #1 to #n.

[0027] Hopping and agile control when varying the second Lo signals #1 to #n will be described in detail using FIG. 4 . In the example of FIG. 4 , the second Lo signals #1 to #n generated by the second signal generating circuits 341 to 34n are varied to individually hop the multi-tone signals f1 to fn. In the example of FIG. 4 , the multi-tone signals f1 to fn are varied in frequency at intervals of multiple pulses, whereas in the case of agile control, the frequency is varied for each pulse. By individually setting hopping or agile control for each multi-tone signal, the system becomes less susceptible to the effects of threatening jamming waves and achieves a high ECCM effect.

[0028] As shown in FIG. 1 , when n multi-tone signals are transmitted as radar signals from the antenna 11 and reflected by a target, the n multi-tone signals are received by the antenna 11 as echo signals. The echo signals are distributed by the distributor 16 to the division circuits (reception) #1 to #n, one for each multi-tone signal, and processed by the signal processing circuits 211 to 21n, resulting in target detection. When the antenna 11 receives a threat jamming wave along with the echo signals, the signal processing circuits 211 to 21n detect jamming. If the signal processing result is "target detected and jamming not detected," each of the signal processing circuits 211 to 21n outputs target detection data to the integrated processing circuit 22. If the signal processing result is "target not detected" or "target detected and jamming detected," each of the signal processing circuits 211 to 21n rejects the target detection data. In other words, the target detection data output to the integrated processing circuit 22 is always target detection data in which a target is detected and jamming is not detected.

[0029] An example configuration of the integrated processing circuit 22 will now be described with reference to Fig. 5. The integrated processing circuit 22 includes a target detection data selector 221 that selects at least one of the target detection data #1 to #n output from the signal processing circuits 211 to 21n, a correlation determiner 222 that performs a correlation determination process for each selected target detection data and adopts target detection data that satisfies predetermined correlation conditions, a target detection data output unit 223 that outputs the adopted target detection data, and a storage unit 232 that stores information data. In the correlation determination process performed by the correlation determiner 222, a correlation determination is performed with past target detection data for each selected target detection data, and the target detection data is rejected if it does not satisfy a correlation condition consisting of at least one of the target's direction, distance, speed, and direction of travel, and is adopted if it satisfies the correlation condition. For example, the correlation determination unit 222 determines at least one of the target's bearing, distance, speed, and direction of travel, etc., based on the correlation with past target detection data, and sets a correlation condition that the difference between the current data and at least one of the previously determined bearing, distance, speed, and direction of travel, etc., is within a predetermined threshold. The storage unit 232 is a semiconductor memory, flash memory, magnetic disk, etc., and stores information data necessary for performing the correlation determination process. For example, the target detection data is stored in the storage unit 232. The target detection data may be stored in advance, or target detection data input to the integrated processing circuit 22 as needed may be stored.

[0030] The correlation determination unit 222 may, for example, adopt the first target detection data that satisfies the correlation condition from among the plurality of target detection data sequentially input to the correlation determination unit 222, or may randomly adopt the target detection data that satisfy the correlation condition. The target detection data may be output, for example, by display on a screen or by output to an external device or system. The integrated processing circuit 22 also includes a radar waveform data generation unit 224 that generates the aforementioned radar waveform data. The radar waveform data generation unit 224 outputs the generated radar waveform data to the DA converter 23.

[0031] Here, jamming detection will be described in detail. For example, the antenna 11 may receive power jamming as jamming. When the antenna 11 receives high-power jamming, such as continuous waves, noise waves, or sweep waves, it may be unable to detect a multi-tone signal reflected from a target, even though it receives some kind of signal. In other words, the signal processing circuits 211 to 21n determine that jamming has been detected when the strength of the received signal exceeds a threshold and the multi-tone signal reflected from the target cannot be detected. Also, for example, the antenna 11 may receive deceptive jamming as jamming. The antenna 11 receives multiple multi-tone signals from false targets in addition to the multi-tone signal reflected from the target. The signal processing circuits 211 to 21n determine that jamming has been detected when the number of detected echo signals, which are multi-tone signals, increases. Furthermore, the direction, distance, speed, and direction of travel of the false target multi-tone signals may change with each reception. The correlation determination unit 222 rejects target detection data that changes with each reception and does not satisfy the correlation conditions, and determines that the data is deceptive jamming. Furthermore, for example, the antenna 11 may receive a jamming signal that matches a multi-tone signal reflected from a target. Because the correlation determination unit 222 determines the correlation condition for each target detection data of a selected split circuit, if the multi-tone signal reflected from a target matches the jamming signal, it is difficult to detect the target detection data as jamming. Therefore, the correlation determination unit 222 performs a correlation determination to determine whether the correlation condition is satisfied for each target detection data of a selected split circuit, and whether the correlation condition with target detection data of other selected split circuits is satisfied. By comparing the target detection data of multiple split circuits and performing the correlation determination, the correlation determination unit 222 can detect jamming signals even when the multi-tone signal matches the jamming signal.

[0032] As described above, the multi-tone radar 100 performs target detection using a multi-tone signal that is not affected by threat jamming waves, thereby achieving a high ECCM effect. The ECCM effect of the multi-tone radar will be described with reference to FIG. 6 . As shown in FIG. 6 , the output frequency range of the multi-tones of the multi-tone radar 100 is sufficiently wider than the instantaneous transmission bandwidth of the threat jamming waves generated by the ECM device. Therefore, even if the ECM device jams the radar signal by frequency tracking, at least one of the multi-tones f1 to fn is always unaffected by the jamming. In the example shown in FIG. 6 , the ECM device frequency tracks the radar signal, transitioning from a state in which the multi-tones f2 and f3 are affected by jamming to a state in which the multi-tones fn-1 and fn are affected by jamming, while there are always multi-tones that are not affected by jamming. The multi-tone radar 100 performs target detection for each multi-tone signal and employs target detection data obtained by signal processing of the unjammed multi-tone signal, thereby enabling stable target detection to be maintained even when the jamming frequency rapidly changes in accordance with the radar frequency.

[0033] Next, the flow of the target detection process executed by the multi-tone radar 100 will be described with reference to FIG. 7 . The target detection process begins when the multi-tone radar 100 is activated. The DA converter 23 performs DA conversion on the radar waveform data output from the integrated processing circuit 22 to generate a second IF signal (step S11). The second IF signal is then distributed by the distributor 24 to the division circuits (transmission) #1 to #n. The division circuit (transmission) #1 frequency-converts the distributed second IF signal and transmits the radar signal #1 from the antenna 11 (step S12-1). The division circuit (reception) #1 receives the echo signal #1, which is the radar signal #1 reflected from the target, from the antenna 11 (step S13-1). The signal processing circuit 211 frequency-converts the echo signal #1 and performs signal processing based on the AD-converted digital signal (step S14-1), generating target detection data #1 indicating the target detection result. If the signal processing circuit 211 detects interference as a result of signal processing (step S15-1; YES), it rejects the target detection data #1 (step S16-1). If it does not detect interference (step S15-1; NO), it determines whether or not a target has been detected (step S17-1). If it does not detect a target (step S17-1; NO), it rejects the target detection data #1 (step S16-1). If it detects a target (step S17-1; YES), it outputs the target detection data #1 to the integrated processing circuit 22 (step S18-1).

[0034] The dividing circuit (transmitting) #2 frequency-converts the divided 2nd IF signal and transmits the radar signal #2 from the antenna 11 (step S12-2). The dividing circuit (receiving) #2 receives the echo signal #2, which is the radar signal #2 reflected from the target, from the antenna 11 (step S13-2). The signal processing circuit 212 frequency-converts the echo signal #2 and performs signal processing based on the AD-converted digital signal (step S14-2), generating target detection data #2 indicating the target detection result. If the signal processing circuit 211 detects interference as a result of signal processing (step S15-2; YES), it rejects the target detection data #2 (step S16-2). If it does not detect interference (step S15-2; NO), it determines whether a target has been detected (step S17-2). If it does not detect a target (step S17-2; NO), it rejects the target detection data #2 (step S16-2). If a target is detected (step S17-2; YES), target detection data #2 is output to the integrated processing circuit 22 (step S18-2).

[0035] The dividing circuit (transmitting) #n frequency-converts the divided 2nd IF signal and transmits the radar signal #n from the antenna 11 (step S12-n). The dividing circuit (receiving) #n receives the echo signal #n, which is the radar signal #n reflected from the target, from the antenna 11 (step S13-n). The signal processing circuit 211 frequency-converts the echo signal #n and performs signal processing based on the AD-converted digital signal (step S14-n), generating target detection data #n indicating the target detection result. If the signal processing circuit 211 detects interference as a result of signal processing (step S15-n; YES), it rejects the target detection data #n (step S16-n). If it does not detect interference (step S15-n; NO), it determines whether a target has been detected (step S17-n). If it does not detect a target (step S17-n; NO), it rejects the target detection data #n (step S16-n). If a target is detected (step S17-n; YES), target detection data #n is output to the integrated processing circuit 22 (step S18-n). The division circuits (transmission) #3 to #n-1 also perform the same processing.

[0036] The target detection data selector 221 of the integrated processing circuit 22 selects at least one target detection data from the target detection data #1 to #n output from the signal processing circuits 211 to 21n (step S19). The correlation determiner 222 performs a correlation determination for each selected target detection data to determine whether the correlation conditions are met and whether the correlation conditions are met with the target detection data of the other selected divided circuits (step S20). If the correlation conditions are not met (step S20; NO), the correlation determiner 222 discards the target detection data (step S21). If the correlation conditions are met (step S20; YES), the correlation determiner 222 adopts the target detection data (step S22). The target detection data output unit 223 outputs the adopted target detection data (step S23), and the process ends.

[0037] As described above, according to the first embodiment, the radar includes division circuits corresponding to multiple frequency ranges obtained by dividing the transmission / reception frequency range of a multi-tone radar, performs radar signal hopping or agile within the frequency range of the division circuits, detects targets and interference based on the echo signals for each division circuit to generate target detection data, and selects the target detection data of a division circuit in which a target was detected but interference was not detected, thereby widening the bandwidth and realizing stable target detection even when the interference frequency changes rapidly to track the radar frequency. Furthermore, by making the configuration before the distributor 16 in the reception system and the configuration after the combiner 28 in the transmission system common to each division circuit, an increase in circuit size due to the widening of the bandwidth can be suppressed.

[0038] (Embodiment 2) In Embodiment 1, the multi-tone radar 100 is used only for "radar," but in Embodiment 2, it is used for "radar + jamming." In addition to the configuration of Embodiment 1, the multi-tone radar 100 of Embodiment 2 receives notification of the detection results of threat radar waves from an ESM (Electronic Support Measures) device, an RWR (Radar Warning Receiver) device, or the like mounted on its own platform, and allocates one or more waves from the multi-tone signals used as radar signals as jamming signals to the threat radar. The detection results of the threat radar waves include the frequency of the threat radar waves.

[0039] An example of an aircraft equipped with a multi-tone radar 100 having a "radar + jamming" configuration in which one or more arbitrary multi-tone signals among the multi-tone signals are assigned as jamming signals to a threat radar will be described with reference to FIGS. 8 and 9.

[0040] In the example of Figure 8, the multi-tone radar 100 installed on the aircraft assigns one wave of the multi-tone signal used as a radar signal to a jamming signal. When the ESM or RWR installed on the aircraft detects a threat radar wave and notifies the multi-tone radar 100 of the detection result, the multi-tone radar 100 sets tuning to the threat radar wave and a jamming technique for a multi-tone signal in a frequency range that includes the frequency of the threat radar wave, and transmits the multi-tone signal. The jamming technique that can be used when assigning a jamming signal to a multi-tone signal is so-called power jamming, which increases the noise power of the radar receiver of the threat aircraft and deteriorates the signal-to-noise (SN) ratio.

[0041] In the example of Figure 9, the frequency of the threat radar wave included in the detection result of the threat radar wave is included in the frequency range of the f2 multi-tone signal, so the f2 multi-tone signal is assigned to the jamming signal and a self-jamming wave that counters the threat radar wave is transmitted. Note that even if no jamming technique is set, simply tuning one or more waves of the multi-tone signal to the frequency of the threat radar wave may produce a jamming effect that causes the threat radar to erroneously detect the position of the self-aircraft, i.e., a so-called deceptive jamming effect.

[0042] When one or more waves of the multi-tone signal used as a radar signal are assigned to a jamming signal, the second Lo signal of the dividing circuit assigned to the jamming signal is superimposed with a local signal as a signal for a power jamming technique such as noise or sweep, or the radar waveform data is switched to jamming waveform data. In this jamming signal generation method, the jamming function of the multi-tone radar 100 is basically limited to power jamming, but by adding a dividing circuit dedicated to jamming, it is possible to perform not only power jamming but also deceptive jamming.

[0043] FIG. 10 shows how the multi-tone radar 100 is used and how the multi-tone signals are allocated. As shown in FIG. 10 , when the multi-tone radar 100 is used only for "radar," the number of radar signals a is n waves, the number of power jamming signals b is 0 waves, and the number of deceptive jamming signals c is 0 waves. When the multi-tone radar 100 is used for "radar + power jamming," the number of radar signals a is 1 to n-1 waves, the number of power jamming signals b is n-1 to 1 waves, and the number of deceptive jamming signals c is 0 waves. In this case, since the number of multi-tone signals n is allocated to radar and power jamming, the relationship between the number of multi-tone signals n, the number of radar signals a, and the number of power jamming signals b is n = a + b. When the multi-tone radar 100 is used for "radar + deceptive jamming," the number of radar signals a is n waves, the number of power jamming signals b is 0 waves, and the number of deceptive jamming signals c is set to any value equal to or greater than 1 wave. In this case, it is necessary to add independent division circuits equal to the number of deceptive jamming signals. When the usage of the multi-tone radar 100 is "radar + power jamming + deceptive jamming," the number of radar signals a is 1 to n-1 waves, the number of power jamming signals b is n-1 to 1 waves, and the number of deceptive jamming signals c is set arbitrarily to 1 wave or more. In this case, since the number of multi-tone signals n is assigned to radar and power jamming, the relationship between the number of multi-tone signals n, the number of radar signals a, and the number of power jamming signals b is n = a + b. It is also necessary to add independent division circuits equal to the number of deceptive jamming signals. When the usage of the multi-tone radar 100 is "jamming" only, the number of radar signals a is 0 waves, the number of power jamming signals b is n waves, and the number of deceptive jamming signals c is set arbitrarily to 1 wave or more. In this case, it is necessary to add independent division circuits equal to the number of deceptive jamming signals.

[0044] The configuration of a multi-tone radar 100 using the "radar + power jamming" method will now be described with reference to FIG. 11 . In the following description, a jamming signal used for power jamming will be referred to as a power jamming signal. In FIG. 11 , the configuration before the distributor 16 in the receiving system and the configuration after the combiner 28 in the transmitting system are the same as those in the first embodiment, and therefore will not be described. The integrated processing circuit 22 of the multi-tone radar 100 switches the division circuit (transmission) from radar use to jamming use and vice versa based on the detection results notified from the ESM or RWR. The integrated processing circuit 22 generates waveform data for radar and jamming waveform data, and outputs radar waveform data to the division circuit (transmission) switched for radar use and jamming waveform data to the division circuit (transmission) switched for jamming use.

[0045] Each of the division circuits (transmitting) #1 to #n includes narrow bandpass filters (BPFs) 251 to 25n, mixers 261 to 26n, and wide bandpass filters (BPFs) 271 to 27n. The division circuits also include D-A converters 361 to 36n that convert waveform data output from the integrated processing circuit 22, attenuators (ATTs) 371 to 37n that amplitude-modulate the second IF jamming signals obtained by D-A converting the waveform data in accordance with the control signal output from the integrated processing circuit 22, and switches 381 to 38n that pulse-modulate the amplitude-modulated second IF jamming signals in accordance with the control signal output from the integrated processing circuit 22. Here, n is the number of divisions, or the number of multi-tone signals. Furthermore, the second signal generating circuits 341 to 34n generate second Lo signals #1 to #n in accordance with the input control signal and input them to the mixers of the corresponding division circuits (transmitting). The second signal generating circuits 341 to 34n input a second Lo signal to the mixer of the division circuit (transmission) assigned for jamming purposes, which is, for example, noise or sweep, and the second Lo signal to input to the mixer of the division circuit (transmission) used for radar purposes, which is, for example, CW (Continuous Wave).

[0046] Next, an example of the configuration of the integrated processing circuit 22 will be described with reference to Fig. 12. The integrated processing circuit 22 includes a target detection data selector 221, a correlation determiner 222, a target detection data output unit 223, a radar waveform data generator 224, and a detection result acquirer 225 that acquires detection results notified from the ESM or RWR. The integrated processing circuit 22 also includes switching units 2261-226n that switch the divided circuits #1-#n between radar and jamming, jamming waveform data generators 2271-227n that generate jamming waveform data, amplitude modulators 2281-228n that transmit control signals to ATTs 371-37n, pulse modulators 2291-229n that transmit control signals to switches 381-38n, and second Lo signal controllers 2311-231n that output control signals to second signal generating circuits 341-34n.

[0047] The integrated processing circuit 22 assigns some or all of the multiple divided circuits to radar divided circuits or power jamming divided circuits. The detection result acquisition unit 225 assigns a multi-tone signal in a frequency range including the frequency of the threat radar wave included in the detection result notified from the ESM or RWR to the power jamming signal, and outputs an instruction signal to the switching unit of the corresponding divided circuit to switch from radar to jamming. When the switching units 2261 to 226n receive an instruction signal from the detection result acquisition unit 225 to switch from radar to jamming, they switch the corresponding divided circuit from radar to jamming. The radar waveform data generation unit 224 distributes the generated radar waveform data to the switching units 2261 to 226n. The jamming waveform data generation units 2271 to 227n each generate jamming waveform data and send it to the switching units 2261 to 226n. The jamming waveform data may be, for example, noise or sweep. When switching the corresponding dividing circuit to jamming, each of the switching units 2261 to 226n outputs jamming waveform data to the corresponding DA converter 361 to 36n, and when switching to radar, outputs radar waveform data to the corresponding DA converter 361 to 36n.

[0048] The amplitude modulation units 2281 to 228n each output a control signal to the ATTs 371 to 37n to perform amplitude modulation when the division circuit (transmission) is switched to jamming mode. The pulse modulation units 2291 to 229n each output a control signal to the switches 381 to 38n to perform pulse modulation when the division circuit (transmission) is switched to jamming mode. When the division circuit (transmission) is used for radar, amplitude modulation and pulse modulation are not performed. The second Lo signal control units 2311 to 231n output control signals for setting noise, sweep, etc. to the signal generation second circuits 341 to 34n when the division circuit (transmission) is switched to jamming mode and jamming waves are superimposed on the second Lo signal.

[0049] 11 and 12 , the cases where the multi-tone signal is used as a radar signal and where it is assigned to a power jamming signal will be described using division circuit (transmission) #1. When the multi-tone signal of division circuit (reception) #1 is used as a radar signal, switching unit 2261 outputs the radar waveform data generated and distributed by radar waveform data generation unit 224 to DA converter 361. The radar waveform data output from switching unit 2261 is DA converted by DA converter 361, and a second IF signal for radar is output. The second IF signal for radar is band-limited by BPF (narrow) 251 via ATT 371 and switch 381. At this time, ATT 371 and switch 381 do not perform amplitude modulation or pulse modulation, respectively.

[0050] The second IF signal for radar that has passed through the BPF (narrow) is frequency converted by the mixer 261 using the second Lo signal #1 to a first IF signal for radar, and is then band-limited by the BPF (wide) 271. The first IF signal for radar that has passed through the BPF (wide) 271 is combined with the first IF signals of the division circuits (transmission) #2 to #n by the combiner 28 to become a multi-tone signal.

[0051] When the multi-tone signal of division circuit (transmission) #1 is assigned to a power jamming signal, the detection result acquisition unit 225 instructs the switching unit 2261 of division circuit (transmission) #1 to switch from radar to jamming. When the switching unit 2261 is instructed by the detection result acquisition unit 225 to switch from radar to jamming, the switching unit 2261 outputs the jamming waveform data generated by the jamming waveform data generation unit 2271 to the DA converter 361.

[0052] The DA converter 361 performs DA conversion on the jamming waveform data output from the switching unit 2261 and outputs a jamming 2nd IF signal. The ATT 371 performs amplitude modulation on the jamming 2nd IF signal output from the DA converter 361 in accordance with a control signal from the amplitude modulation unit 2281. The switch 381 performs pulse modulation on the amplitude-modulated jamming 2nd IF signal in accordance with a control signal from the pulse modulation unit 2291, and outputs the pulse-modulated jamming 2nd IF signal to the BPF (narrow) 251. The pulse-modulated jamming 2nd IF signal is band-limited by the BPF (narrow) 251. The jamming 2nd IF signal that has passed through the BPF (narrow) is frequency-converted by the mixer 261 to a jamming 1st IF signal, and is band-limited by the BPF (wide) 271. The 1st IF signal for interference that has passed through BPFs (wide) 271 to 27n is combined with the 1st IF signals of dividing circuits (transmission) #2 to #n by combiner 28 to generate a multi-tone signal. When an interference wave is superimposed on a 2nd Lo signal, 2nd Lo signal control section 2311 can widen the band of the 1st IF signal for interference output from mixer 261 by outputting a control signal for setting noise, sweep, etc. to second signal generation circuit 341.

[0053] Although the configuration after the combiner 28 is omitted, the multi-tone signal is up-converted by the 1stLo signal by the mixer 29 and frequency-converted to an RF signal. The RF signal is limited to a set frequency band and bandwidth by the filter bank 30, amplified by the amplifier 31, and transmitted from the antenna 11 via the duplexer 12 as a power jamming signal and a radar signal.

[0054] If the frequency of the threat radar wave fluctuates and is no longer included in the frequency range of the multi-tone signal of division circuit (transmission) #1, detection result acquisition unit 225 instructs switching unit 2261 of division circuit (transmission) #1 to switch from jamming to radar. When instructed to switch from jamming to radar by detection result acquisition unit 225, switching unit 2261 outputs the radar waveform data generated and distributed by radar waveform data generation unit 224 to D-A converter 361.

[0055] Next, the configuration of a multi-tone radar 100 whose usage method is "radar + power jamming + deceptive jamming" will be described using Fig. 13. In Fig. 13, the configuration before the divider 16 in the receiving system and the configuration after the combiner 28 in the transmitting system are the same as those in the first embodiment, and therefore will be omitted. The multi-tone radar 100 includes a jamming splitter circuit #x in addition to splitter circuits #1 to #n. In the figure, splitter circuit (receiving) #x and splitter circuit (transmitting) #x are denoted as #x (receiving) and #x (transmitting), respectively.

[0056] Since power jamming has been described using Figures 11 and 12, here we will explain the splitter circuit #x used for deception jamming. In the following description, the jamming signal used for deception jamming is referred to as the "deception jamming signal." Splitter circuit (receiving) #x receives threat radar waves. Although the configuration before the splitter 16 is omitted, the threat radar waves received by the antenna 11, along with echo signals, are passed through the duplexer 12 and amplified by the amplifier 13. The amplified threat radar waves and echo signals are limited to a set frequency band and frequency band by the filter bank 14, and are frequency-converted to a first IF signal by the mixer 15 using the first Lo signal. The first IF signal output from the mixer 15 is distributed by the splitter 16 to splitter circuits (receiving) #1 to #n and splitter circuit (receiving) #x. At this time, the first IF signal of the threat radar wave is distributed to splitter circuit (receiving) #x according to the detection result of the threat radar wave.

[0057] The division circuit (reception) #x includes a mixer 18x that is the same as the mixers 181 to 18n. The first IF signal of the threat radar wave is frequency-converted by the mixer 18x to a second IF signal of the threat radar wave using a second Lo signal #x generated by the second signal generation circuit 34x.

[0058] In addition to the mixer 18x, the division circuit (reception) #x includes a BPF (wide) 39x that limits the bandwidth of the second IF signal of the threat radar wave output from the mixer 18x. To maximize the jamming band of the deception jamming, the bandwidth limited by the BPF (wide) 39x is set to the same bandwidth as the hopping range and agile range, similar to the BPFs (wide) 171-17n. The second IF signal of the threat radar wave that passes through the BPF (wide) 39x is input to the integrated processing circuit 22. The waveform of the second IF signal of the threat radar wave input to the integrated processing circuit 22 is temporarily stored, and the integrated processing circuit 22 outputs the second IF signal with the temporarily stored waveform.

[0059] The division circuit (transmitting) #x includes a mixer 26x identical to the mixers 261-26n, a DA converter 36x identical to the DA converters 361-36n, an ATT 37x identical to the ATTs 371-37n, and a switch 38x identical to the switches 381-38n. The DA converter 36x performs DA conversion on the jamming waveform data output from the integrated processing circuit 22 to generate and output a jamming second IF signal. The ATT 37x performs amplitude modulation on the jamming second IF signal output from the DA converter 36x in accordance with a control signal from the integrated processing circuit 22. The switch 38x performs pulse modulation on the amplitude-modulated jamming second IF signal in accordance with a control signal from the integrated processing circuit 22.

[0060] In addition to the mixer 26x, the D-A converter 36x, the ATT 37x, and the switch 38x, the division circuit (transmission) #x includes a combiner 40x that combines a second IF signal of the threat radar wave waveform output from the integrated processing circuit 22 with a pulse-modulated second IF signal for jamming to output a second IF signal for jamming, and a BPF (wide) 41x that limits the bandwidth of the second IF signal for jamming output from the combiner 40x. The BPF (wide) 41x is the same as the BPF (wide) 39x. The second IF signal for jamming that passes through the BPF (wide) 41x is frequency-converted by the mixer 26x to a first IF signal for jamming. The first IF signal for jamming is combined with the first IF signals of the division circuits (transmission) #1 to #n by the combiner 28 to generate a multi-tone signal.

[0061] Although the configuration after the combiner 28 is omitted, the multi-tone signal is up-converted by the mixer 29 using the 1stLo signal and frequency-converted to an RF signal. The RF signal is limited to a set frequency band and bandwidth by the filter bank 30, amplified by the amplifier 31, and transmitted as a deception jamming signal and a radar signal from the antenna 11 via the duplexer 12. When at least one of the division circuits #1 to #n is assigned to power jamming, the signal is transmitted as a deception jamming signal, a power jamming signal, and a radar signal.

[0062] Next, an example of the configuration of the integrated processing circuit 22 will be described with reference to FIG. The integrated processing circuit 22 includes a target detection data selection unit 221, a correlation determination unit 222, a target detection data output unit 223, a radar waveform data generation unit 224, a detection result acquisition unit 225, switching units 2261 to 226n, jamming waveform data generation units 2271 to 227n, amplitude modulation units 2281 to 228n, pulse modulation units 2291 to 229n, and second Lo signal control units 2311 to 231n that output control signals to the signal generation second circuits 341 to 34n, as well as a jamming waveform data generation unit 227x that generates jamming waveform data corresponding to the divided circuit #x, an amplitude modulation unit 228x that transmits a control signal to the ATT 37x, a pulse modulation unit 229x that transmits a control signal to the switch 38x, and a second Lo signal control unit 231x that outputs a control signal to the signal generation second circuit 34x. The integrated processing circuit 22 also includes a DRFM (Digital Radio Frequency Memory) 230 that temporarily stores the waveform of the second IF signal of the input threat radar wave and outputs the second IF signal of the stored waveform after a set delay time. The DRFM 230 performs A-D conversion on the waveform of the second IF signal of the input threat radar wave, temporarily stores the digital data in memory, and after a set delay time has elapsed, performs D-A conversion on the stored digital data and outputs the second IF signal of the waveform of the threat radar wave.

[0063] The jamming 2nd IF signal transmitted from antenna 11 is received by the radar of the threat aircraft with a time delay from the actual echo wave of the threat radar wave. The deceptive jamming 2nd IF signal, which is a combination of the same waveform as the 2nd IF signal of the threat radar wave stored in DRFM 230 and the jamming 2nd IF signal, is frequency-converted and transmitted from antenna 11 as a deceptive jamming signal, causing the radar of the threat aircraft to mistakenly recognize that our aircraft is at a different distance than it actually is.

[0064] In this embodiment, the second Lo signals #1 to #n generated by the second signal generating circuits 341 to 34n used for the radar signals are varied to make the radar signals hopping or agile, but the frequency of the second Lo signal #x generated by the second signal generating circuit 34x used for the jamming signals is not varied to prevent the jamming signals from hopping or agile. Note that if the threat radar waves are hopping or agile, the second Lo signal #x may be varied in accordance with the fluctuations in the frequency of the threat radar waves.

[0065] The configuration of the multi-tone radar 100 whose usage method is "radar + deceptive jamming" is, for example, a configuration in which the components of the second signal generating circuit 34x, the distributor 35x, and the dividing circuit #x shown in Fig. 13 are added to the configuration shown in Fig. 1, and the configuration of the integrated processing circuit 22 is a configuration in which the components of the jamming waveform data generating unit 227x, the amplitude modulation unit 228x, the pulse modulation unit 229x, the DRFM 230, and the 2nd Lo signal control unit 231x shown in Fig. 14 are added to the configuration shown in Fig. 5. The dividing circuit #x is a dividing circuit for deceptive jamming, and the dividing circuits #1 to #n are dividing circuits for radar.

[0066] The configuration of the multi-tone radar 100 whose only usage is "jamming" is, for example, the same as the configuration shown in Figure 13, and the configuration of the integrated processing circuit 22 is the same as the configuration shown in Figure 14, except that the target detection data selector 221, correlation determiner 222, target detection data output unit 223, radar waveform data generator 224, detection result acquirer 225, and switchers 2261 to 226n are removed. The jamming waveform data generators 2271 to 227n may each generate jamming waveform data and output it to the corresponding DA converters 361 to 36n, or one jamming waveform data generator may distribute the jamming waveform data to the corresponding DA converters 361 to 36n. Divider circuit #x is a divider circuit for deception jamming, and divider circuits #1 to #n are divider circuits for power jamming.

[0067] As described above, according to the second embodiment, part or all of the multi-tone signal of the multi-tone radar can be used as a jamming signal for a threat radar wave. The multi-tone radar 100 according to the second embodiment includes dividing circuits corresponding to multiple frequency ranges obtained by dividing the transmission and reception frequency range of the multi-tone radar, and the multiple dividing circuits include a dividing circuit for radar and a dividing circuit for jamming, thereby enabling the radar and EW device to have a wide bandwidth and suppressing an increase in the size of the hardware.

[0068] Furthermore, EW devices generally have a problem in that there are time periods during which jamming signals are not transmitted, such as by stopping transmission of jamming signals while transmitting radar signals or by switching jamming frequencies for multiple threat radars using time control. In contrast, the multi-tone radar 100 according to the second embodiment can simultaneously transmit radar signals and jamming signals because the frequencies of the wideband multi-tone radar signals are sufficiently separated. By increasing the number of assigned jamming signals, simultaneous jamming of multiple threat radars can be achieved. This prevents a decrease in jamming effectiveness due to time control.

[0069] In the above-described first and second embodiments, the correlation determination unit 222 of the integrated processing circuit 22 determines the correlation between each selected target detection data and past target detection data, discards the target detection data if it does not satisfy a correlation condition consisting of at least one of the target's direction, distance, speed, and direction of travel, and adopts the target detection data if it does satisfy the correlation condition, and the target detection data output unit 223 outputs the target detection data adopted by the correlation determination unit 222. However, this is not limited to this. The target detection data output unit 223 may also output the target detection data selected by the target detection data selector 221. In this case, the integrated processing circuit 22 does not need to include the correlation determination unit 222.

[0070] In the first and second embodiments described above, the multi-tone radar 100 transmits and receives multi-tone signals by operating all of the multiple divider circuits. However, this is not limited to this. The number of divider circuits that are operated among the multiple divider circuits can be set. For example, one of the multiple divider circuits may be operated to transmit and receive a single wave, or two or more of the multiple divider circuits may be operated to transmit and receive multi-tone signals. Furthermore, by switching the number of divider circuits that are operated among the multiple divider circuits, it may be possible to switch between single-wave transmission and reception and multi-tone transmission and reception.

[0071] In the above-described first and second embodiments, the multi-tone radar 100 detects interference in order to avoid the influence of radar interference caused by an ECM device, but this is not limiting. For example, clutter may be detected as interference in order to remove the influence of natural physical phenomena such as clutter.

[0072] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0073] Various aspects of the present disclosure are summarized below as appendices.

[0074] (Supplementary Note 1) A multi-tone radar that transmits a multi-tone signal as a jamming signal and a radar signal that jams a threat radar wave, and receives a multi-tone signal including the radar signal reflected from a target as an echo signal, the multi-tone radar comprising a plurality of divider circuits that transmit the multi-tone signal in a plurality of frequency ranges that are obtained by dividing the transmission and reception frequency range of the multi-tone radar, the plurality of divider circuits including a radar divider circuit that transmits the multi-tone signal as the radar signal and a jamming divider circuit that transmits the multi-tone signal as the jamming signal. (Supplementary Note 2) The multi-tone radar according to Supplementary Note 1, further comprising an integrated processing circuit that assigns some or all of the plurality of divider circuits to the radar divider circuit or the jamming divider circuit that jams power, the integrated processing circuit assigning a divider circuit assigned to a frequency range that includes the frequency of the threat radar wave as the jamming divider circuit. (Supplementary Note 3) The multi-tone radar according to Supplementary Note 2, wherein the integrated processing circuit comprises a switching unit that switches between the radar waveform data and the jamming waveform data so as to output radar waveform data to the radar division circuit and output jamming waveform data to the jamming division circuit. (Supplementary Note 4) The multi-tone radar according to Supplementary Note 3, wherein the integrated processing circuit comprises a detection result acquisition unit that acquires a result of detecting the jamming signal, and the switching unit switches between the radar waveform data and the jamming waveform data based on an instruction signal output from the detection result acquisition unit. (Supplementary Note 5) The multi-tone radar according to any one of Supplements 1 to 4, comprising: a first signal generating circuit that is input to a mixer common to the plurality of division circuits and generates a first local signal that defines a transmission and reception frequency range of the multi-tone radar, and a plurality of second signal generating circuits that are input to individual mixers for the plurality of division circuits and that define which of the plurality of frequency ranges the corresponding division circuit corresponds to. (Supplementary Note 6) The multi-tone radar according to Supplementary Note 5, wherein the integrated processing circuit individually controls the second signal generating circuits corresponding to the jamming division circuits to generate a power jamming signal as the second local signal.(Supplementary Note 7) The multi-tone radar according to Supplementary Note 5 or 6, wherein the integrated processing circuit individually controls the second signal generating circuits corresponding to the jamming splitting circuits to vary the frequency of the second local signal in accordance with fluctuations in the frequency of the threat radar wave, when the threat radar wave is hopping or agile. (Supplementary Note 8) The multi-tone radar according to any of Supplements 1 to 7, wherein the jamming splitting circuits include a deception jamming splitting circuit that transmits a deception jamming signal generated based on the received threat radar wave. (Supplementary Note 9) The multi-tone radar according to Supplementary Note 8, wherein the integrated processing circuit has a DRFM (Digital Radio Frequency Memory) that temporarily stores the waveform of the threat radar wave received by the deception jamming splitting circuit and outputs a signal of the waveform of the threat radar wave with a set delay time, and the deception jamming splitting circuit generates the deception jamming signal based on the signal of the waveform of the threat radar wave output from the DRFM. (Supplementary Note 10) The multi-tone radar according to Supplementary Note 8 or 9, comprising: one antenna; and a duplexer that switches the one antenna between transmission and reception, wherein the duplexer switches between transmitting the radar signal and the jamming signal and receiving the echo signal and the threat radar wave. (Supplementary Note 11) The multi-tone radar according to any of Supplementary Notes 1 to 10, wherein a frequency separation between adjacent frequency ranges of the plurality of frequency ranges is 1.0 / τ hertz or more, where τ is a pulse width of the multi-tone signal. (Supplementary Note 12) A transmission and reception method for multi-tone radar that transmits a multi-tone signal as a jamming signal and a radar signal that jams a threat radar wave, and receives a multi-tone signal including the radar signal reflected from a target as an echo signal, the transmission and reception method comprising: transmitting the multi-tone signal by a plurality of dividing circuits in a plurality of frequency ranges obtained by dividing the transmission and reception frequency range of the multi-tone radar; and at least one dividing circuit of the plurality of dividing circuits transmitting the multi-tone signal as the jamming signal, and the other dividing circuits transmitting the multi-tone signal as the radar signal.

[0075] It should be noted that the present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to explain the disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0076] This application is based on Japanese Patent Application No. 2023-171600, filed on October 2, 2023. The entire specification, claims, and drawings of Japanese Patent Application No. 2023-171600 are incorporated herein by reference.

[0077] 11 Antenna, 12 Transmission / reception switch, 13, 31 Amplifier, 14, 30 Filter bank, 15, 29, 181 to 18n, 18x, 261 to 26n, 26x Mixer, 16, 24, 33, 351 to 35n, 35x Distributor, 22 Integrated processing circuit, 23, 361 to 36n, 36x D-A converter, 28, 40x Combiner, 32 Signal generation first circuit, 100 Multi-tone radar, 171 to 17n, 271 to 27n, 39x, 41x BPF (wide), 191 to 19n, 251 to 25n BPF (narrow), 201 to 20n A-D converter, 211 to 21n Signal processing circuit, 221 Target detection data selection unit, 222 Correlation determination unit, 223 Target detection data output unit, 224 radar waveform data generation unit, 225 detection result acquisition unit, 2261 to 226n switching units, 2271 to 227n, 227x jamming waveform data generation units, 2281 to 228n, 228x amplitude modulation units, 2291 to 229n, 229x pulse modulation units, 230 DRFM, 2311 to 231n, 231x 2nd Lo signal control unit, 232 memory unit, 341 to 34n, 34x signal generation second circuit, 371 to 37n, 37x ATT, 381 to 38n, 38x switch.

Claims

1. A multi-tone radar that transmits a multi-tone signal as a jamming signal and a radar signal that jams a threat radar wave, and receives a multi-tone signal including the radar signal reflected from a target as an echo signal, the multi-tone radar having a plurality of splitting circuits that transmit the multi-tone signal in a plurality of frequency ranges that are obtained by dividing the transmission and reception frequency range of the multi-tone radar, the plurality of splitting circuits including a radar splitting circuit that transmits the multi-tone signal as the radar signal, and a jamming splitting circuit that transmits the multi-tone signal as the jamming signal.

2. The multi-tone radar according to claim 1, further comprising an integrated processing circuit which assigns some or all of the plurality of split circuits to the split circuit for radar or the split circuit for jamming power jamming, and the integrated processing circuit sets the split circuit assigned to a frequency range including the frequency of the threat radar wave as the split circuit for jamming.

3. A multi-tone radar as described in claim 2, wherein the integrated processing circuit is provided with a switching unit that switches between the radar waveform data and the jamming waveform data so as to output radar waveform data to the radar division circuit and output jamming waveform data to the jamming division circuit.

4. The multi-tone radar according to claim 3, wherein the integrated processing circuit includes a detection result acquisition unit that acquires the results of detecting the jamming signal, and the switching unit switches between the radar waveform data and the jamming waveform data based on an instruction signal output from the detection result acquisition unit.

5. A multi-tone radar as claimed in any one of claims 1 to 4, comprising: a first signal generating circuit which is input to a mixer common to the plurality of dividing circuits and generates a first local signal which defines a transmission and reception frequency range of the multi-tone radar; and a plurality of second signal generating circuits which are input to individual mixers for each of the plurality of dividing circuits and generate second local signals which define which of the plurality of frequency ranges the corresponding dividing circuit corresponds to.

6. The multi-tone radar according to claim 5, wherein the integrated processing circuit individually controls the second signal generating circuit corresponding to the jamming division circuit to generate a power jamming signal as the second local signal.

7. The multi-tone radar according to claim 5 or 6, wherein the integrated processing circuit individually controls the second signal generating circuit corresponding to the jamming split circuit when the threat radar wave is hopping or agile, and varies the frequency of the second local signal in accordance with the variation in the frequency of the threat radar wave.

8. A multi-tone radar as claimed in any one of claims 1 to 7, wherein the jamming splitting circuit includes a deceptive jamming splitting circuit that transmits a deceptive jamming signal generated based on the received threat radar wave.

9. The multi-tone radar as described in claim 8, wherein the integrated processing circuit has a DRFM (Digital Radio Frequency Memory) that temporarily stores the waveform of the threat radar wave received by the deception jamming split circuit and outputs a signal of the threat radar wave waveform with a set delay time, and the deception jamming split circuit generates the deception jamming signal based on the signal of the threat radar wave waveform output from the DRFM.

10. A multi-tone radar as described in claim 8 or 9, comprising: one antenna; and a duplexer that switches the one antenna between transmission and reception, wherein the duplexer switches between transmitting the radar signal and the jamming signal and receiving the echo signal and the threat radar wave.

11. The multi-tone radar according to any one of claims 1 to 10, wherein the frequency separation between adjacent frequency ranges of the plurality of frequency ranges is 1.0 / τ Hertz or more, where τ is the pulse width of the multi-tone signal.

12. A transmission and reception method for a multi-tone radar which transmits a multi-tone signal as a jamming signal and a radar signal that jams a threat radar wave, and receives a multi-tone signal including the radar signal reflected from a target as an echo signal, the method comprising: transmitting the multi-tone signal by a plurality of dividing circuits in a plurality of frequency ranges obtained by dividing the transmission and reception frequency range of the multi-tone radar; and at least one of the plurality of dividing circuits transmitting the multi-tone signal as the jamming signal, and the other dividing circuits transmitting the multi-tone signal as the radar signal.

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