JP2016151552A - Signal generator, method, radar system, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar system that increases the performances of identifying and separating a transmission signal component.SOLUTION: The radar system generates signals in which the sub-pulses of a pulse are chirp-modulated at a predetermined frequency bandwidth and the frequency bandwidths of the sub-pulses are arranged substantially randomly.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a signal generation apparatus and method, and a radar apparatus and program including the signal generation apparatus.

  For example, as described in Patent Document 1 and the like, in a MIMO (Multi Input Multi Output) radar apparatus, for example, when a signal subjected to Doppler frequency shift due to high-speed movement of a target is received, an autocorrelation output is increased with an increase in Doppler frequency. Greatly decreases, and the cross-correlation output greatly increases. In Patent Document 1, in order to cope with the problem that a received signal component from a desired transmission sub-radar is attenuated and a signal component from another transmission sub-radar is increased to deteriorate a required signal discrimination performance, The transmission pulse width is divided into a plurality of sub-pulses, each sub-pulse is phase-code modulated with the same reference code, and a multi-level phase code signal obtained by applying phase rotation proportional to the square of time to all sub-pulses. Each of the reception sub-radars includes a signal discriminator (signal discriminator) that performs correlation processing between the reception signal and the transmission signal corresponding to the reception signal. A configuration is disclosed in which a signal that has undergone a Doppler frequency shift can be accurately separated while suppressing the scale.

  For example, Patent Document 2 discloses a radio wave interference-compatible radar device that improves frequency utilization efficiency during frequency hopping when a plurality of radar devices are used in close proximity and performs frequency hopping so as not to cause interference. Is disclosed. In this radar device, the pattern generation unit of the first radar device generates the frequency hopping pattern and frequency channel switching timing of each radar device and distributes them to each radar device, and frequency hopping is required due to external interference. In this case, all the radar devices are synchronized and perform frequency hopping at the same time, thereby reducing the interference between the radar devices and simultaneously improving the frequency utilization efficiency. Note that the radar apparatus of Patent Document 2 receives a received signal from a GPS (Global Positioning System) satellite and extracts a pseudo-random code included therein.

  Furthermore, for example, Patent Document 3 discloses a pulse radar device using band synthesis processing that separates primary echoes and secondary echoes and outputs only primary echoes that are reflected signals from a target.

  Here, the secondary echo will be outlined. FIG. 15 is drawn by the present inventor in order to explain the secondary echo. As shown in FIG. 15, for example, the radar regards a pulse received from the even-numbered transmission pulse # 2X to a round-trip time within the observation range as a pulse reflected from the pulse # 2X. A pulse reflected from a target outside the observation range is not sufficiently received because it is normally sufficiently attenuated. However, in the case of a large target or the like, it may be received by a radar without being sufficiently attenuated. The pulse reflected from the target outside the observation range is actually a reflected signal from the transmission pulse # 2X, but is regarded as an odd (2X + 1) th transmission pulse # 2X + 1 reflected signal (or vice versa) (secondary echo). . By this secondary echo, it is recognized that there is a false target at a position where it cannot be.

  In the case of receiving a signal subjected to Doppler frequency shift, regarding the problem that a required transmission signal component cannot be identified and cannot be separated, in Patent Document 3, the speed compensation unit performs speed compensation processing on the transmission signal to obtain a correlation. Although it is configured, there is a problem that the apparatus configuration becomes large.

  Note that Non-Patent Document 1 discloses a radar that performs processing for continuously transmitting pulses to a plurality of targets before reception.

  In Non-Patent Document 1, it is necessary to be able to identify a signal when receiving a signal at the same time, and when receiving a signal subjected to Doppler frequency shift, the problem that a required transmission signal component cannot be identified and cannot be separated is solved. Means for doing so are not disclosed.

JP 2012-145332 A JP 2005-195450 A JP 2007-240485 A

Farina, A., and Neri, P. “Multitarget interleaved tracking for phased-array radar”, IEE Proceedings F, Communications, Radar and Signal Processing, August 1980

  The analysis of related technology is given below.

  In the configuration disclosed in Patent Document 1, it may be difficult to identify a required transmission signal component from a reception signal that has undergone a Doppler frequency shift due to reflection from a moving target. This is because the Doppler tolerance of the code correlation executed by the transmission signal subjected to the Doppler frequency shift and the reference signal (replica of the desired transmission signal) is low.

  In Patent Document 1, in the Doppler-resistant multilevel phase code generator, as shown in FIG. 16A, the transmission pulse width T is divided into M sub-pulses of length ΔT, and each sub-pulse has a chip length τ. Are phase code modulated with the same N-bit reference code (different codes are selected for the m transmission sub-radars). Since phase code modulation is performed at a time τ (ΔT = N · τ) obtained by dividing the subpulse width ΔT by the number of reception subantennas N, high-speed operation is required for a circuit that switches the modulation. This complicates the configuration of the RF (Radio Frequency) unit. This problem can be solved, for example, by delaying the phase code modulation switching period. In this case, a long pulse width T is required. When the pulse width T becomes long, a new problem arises that it is difficult to detect a short-range target in a radar apparatus that does not perform reception during transmission. The configuration in which reception is not performed during transmission is a necessary operation in a radar apparatus in which interference due to leakage from a transmission signal during reception is a problem (Note that Patent Document 1 describes the embodiment of the present invention). Will be explained in detail later).

  Accordingly, an object of the present invention is to provide an apparatus, a method, and a program for solving at least one of the above-described problems and improving transmission signal component identification / separation performance.

  According to one aspect of the present invention, chirp modulation is performed on a sub-pulse obtained by dividing a pulse into a plurality of predetermined frequency bandwidths, and the order of time-series arrangement of frequency bands for each sub-pulse is A signal generator is provided that generates a substantially random signal.

  According to another aspect of the present invention, sub-pulses obtained by dividing a pulse into a plurality of pulses are chirp modulated with a predetermined frequency bandwidth that is determined in advance, and the order of the time-series arrangement of the frequency bands for each sub-pulse is A signal generation method is provided that generates a substantially random signal.

  According to still another aspect of the present invention, a sub-pulse obtained by dividing a pulse into a plurality of pulses is subjected to chirp modulation with a predetermined frequency bandwidth, and a time-series order of frequency bands for each sub-pulse. A program for causing a computer to execute a process of generating a substantially random signal is provided. According to the present invention, a computer-readable recording medium (semiconductor memory, magnetic / optical disk, etc.) on which the program is recorded is provided.

  According to the present invention, transmission signal component identification / separation performance can be improved.

It is a figure which illustrates the structure of the signal generator of the 1st Embodiment of this invention. It is a figure which shows the output of the frequency hopping signal generator of the 1st Embodiment of this invention. It is a figure explaining the transmission signal which the chirp modulator in a subpulse of the 1st Embodiment of this invention produces | generates. It is a figure which illustrates the signal identification device of the 1st Embodiment of this invention. It is a figure explaining another example of the transmission signal of the 1st Embodiment of this invention. It is a figure explaining another example of the transmission signal of the 1st Embodiment of this invention. It is a figure which illustrates the modification of the 1st Embodiment of this invention. (A), (B) is a figure which illustrates the radar apparatus of the 1st Embodiment of this invention. It is a figure which illustrates the structure of the radar apparatus of the 1st Embodiment of this invention. It is a figure which illustrates the structure of the signal identification part of the radar apparatus of the 1st Embodiment of this invention. It is a figure which illustrates the structure of the radar apparatus of the 2nd Embodiment of this invention. It is a figure which illustrates the structure of the radar apparatus of the 3rd Embodiment of this invention. It is a figure which illustrates the structure of the signal identification part of the radar apparatus of the 4th Embodiment of this invention. (A), (B) is a figure explaining the case where the reflected signal from the target in a different direction is synthesize | combined in the 4th Embodiment of this invention. It is a figure explaining a secondary echo. It is a figure explaining a related technique (patent document 1).

  First, the basic concept of the present invention will be described, followed by embodiments.

  According to the basic concept of the present invention, referring to FIG. 3, the frequency modulation (chirp modulation) of a sub-pulse (sub-pulse width: Δt) obtained by dividing a pulse into a plurality on the time axis is performed with a predetermined frequency bandwidth. And a signal in which the order of the time series in the frequency band of each sub-pulse is almost random (pseudo-random) is generated. In FIG. 3, the frequency for each sub-pulse is f3 (time t0), f1 (time t1), f5 (time t2), f2 (time t3), f4 (time t4), and the sequence on the time axis is almost random ( Pseudo-random pattern).

<Signal generator>
Referring to FIG. 1, a signal generator 10 according to an embodiment of the present invention includes a frequency hopping signal generator 11, a pseudo random number pattern generator 12, and an intra-subpulse chirp modulator 13.

  The pseudo random number pattern generator 12 generates a pseudo random sequence such as an M sequence based on the transmission signal specifications of the transmission antenna (transmission sub antenna) so that the transmission signal between the transmission sub antennas has a low correlation. Based on this, a frequency hopping pattern is generated.

  The frequency hopping signal generator 11 generates a signal whose frequency is changed at sub-pulse intervals based on the transmission signal specifications and the pseudo random number pattern.

  The intra-subpulse chirp modulator 13 performs chirp modulation on the frequency hopping signal having a constant frequency between the subpulses, which is the output of the frequency hopping signal generator 11, so that the signal frequency in the subpulse is linear with respect to time. Shape into a changing chirp signal.

<Signal generator: an example of a frequency hopping pattern>
The frequency hopping signal generator 11 generates a signal as shown in FIG. In FIG. 2, Δf is a unit hopping interval, and Δt is a sub-pulse width. FIG. 2 illustrates a transmission signal (frequency hopping signal) when the number of hopping patterns is five.

<Signal Generator: First Example of Transmission Signal>
The sub-pulse chirp modulator 13 performs chirp modulation within the sub-pulse on the output signal of the frequency hopping signal generator 11 to generate a signal as shown in FIG. The gradient of chirp modulation (frequency change rate of frequency) is set so that the frequency band of the sub-pulse is sufficient for the assumed Doppler frequency shift.

  In the signal generation device 10 of the present embodiment, the frequency hopping pattern for each transmission sub-antenna generated by the pseudo random number pattern generator 12 in order to reduce the cross-correlation between the transmission signals from other signal generators. The frequency hopping signal generator 11 generates a frequency hopped signal at sub-pulse width intervals.

  The sub-pulse chirp modulator 13 performs chirp modulation with a sufficient bandwidth on the assumed Doppler frequency shift so that the received signal that has undergone the Doppler frequency shift has a correlation with the transmission signal.

  Between transmission signals from different transmission sub-antennas, the signal generation apparatus 10 performs different series of frequency hopping for each sub-pulse interval. For this reason, the reception side (signal identification device) can distinguish between transmission signals from different transmission sub-antennas.

  Further, the signal generator 10 performs chirp modulation with a sufficient bandwidth for the assumed Doppler frequency shift in the pulse. For this reason, on the reception side (signal identification device), the received signal subjected to the Doppler frequency shift is a signal having a correlation between the received signal and a required transmission signal component. As a result, when a signal subjected to Doppler frequency shift is received, a required transmission signal component can be accurately identified and separated.

  1 may be implemented by a program executed by a processor (for example, a digital signal processor).

<Signal identification device>
FIG. 4 is a diagram illustrating a configuration of a signal identification device according to one embodiment of the present invention. Referring to FIG. 4, the signal identification device 20 includes a Fourier transformer 21 that transforms a received signal (digital signal) into a frequency domain by Fourier transform using, for example, FFT (Fast Fourier Transform), and a signal generator. A Fourier transformer 24 that Fourier-transforms a replica (replica) of the transmission signal output from the transformer, an interphase processor 22 that computes the phase between the output signals of the Fourier transformer 21 and the Fourier transformer 24, and an interphase processor 22 An inverse Fourier transformer 23 is provided that performs inverse Fourier transform on the output signal by, for example, IFFT (Inverse Fast Fourier Transform). Identify and separate only the signals that you send yourself. In FIG. 4, instead of replicating (replicating) the transmission signal, the signal identification device 20 includes the signal generation device 10 of FIG. 1, and the output of the signal generation device 10 is input to the Fourier transformer 24. Good. 4 may be realized by a program executed by a processor (for example, a digital signal processor or the like).

<Signal Generator: Second Example of Transmission Signal>
In the signal generator 10, a guard band band (an unused frequency band provided to prevent interference with other systems or the like using adjacent frequency bands) as shown in FIG. 5 may be provided. The waveform subjected to the Doppler frequency shift has poor autocorrelation and cross-correlation characteristics due to interference with different frequency bands. As a workaround, as shown in FIG. 5, a guard band band is provided for the assumed Doppler frequency shift. Thereby, interference can be avoided. However, in this case, it is necessary to reduce the bandwidth of chirp modulation or increase the bandwidth used in chirp modulation. When the chirp modulation bandwidth is narrowed, the correlation gain is lowered. Increasing the bandwidth used for chirp modulation causes waste in bandwidth usage.

<Signal generator: Third example of transmission signal>
In the signal generator 10, as shown in FIG. 6, it is good also as a waveform which combined the chirp signal of a different inclination within a subpulse continuously. In order to avoid interference in different frequency bands when subjected to Doppler frequency shift, interference is reduced by making the slopes of chirps at different locations different from each other. Compared with the case of providing a guard band, the effect of avoiding interference is low, but it is not necessary to narrow the bandwidth of chirp modulation or increase the bandwidth to be used. In FIG. 6, the sub-pulse width is divided into two sections, and each section has a different slope. The sub-pulse width may be divided into a plurality of sections, and the slope may be different for each section. However, since the sub-pulses are divided, it is necessary to increase the switching speed of the frequency modulation.

<Another example of signal generator>
FIG. 7 is a diagram illustrating the configuration of another form of signal generation apparatus. In the signal generator 10 of FIG. 1, chirp modulation is performed between subpulses with respect to the frequency hopping waveform. In the signal generation device 30 of FIG. 7, chirp modulation between pulses is first created by the chirp signal generator 31 based on the transmission signal specifications. The sub pulse divider 32 divides the pulse into sub pulses. The subpulse rearranger 33 rearranges the subpulses based on the frequency hopping pattern generated by the pseudo random number pattern generator 34 to generate the same waveform as in FIG. 7 may be realized by a program executed by a processor (for example, a digital signal processor).

<Radar wave transmitter>
FIG. 8A illustrates the structure of a radar wave transmission device according to one embodiment of the present invention. A transmission signal (before RF processing) from the signal generation unit 41 including the signal generation device 10 or 30 of FIG. 1 or 7 is modulated by the transmission RF unit 42 into a transmission signal that can be radiated by the antenna unit 43. The antenna unit 43 radiates the transmission signal from the transmission RF unit 42 to the space.

<Radar wave receiver>
FIG. 8B illustrates a configuration of a radar wave receiving device according to one embodiment of the present invention. The reception signal (for example, the transmission signal is reflected by the target and receives the Doppler frequency shift) is received from the antenna unit 51, and the reception RF unit 52 receives and amplifies and demodulates the reception signal received by the antenna unit 51. FIG. The signal discriminating unit 53 comprising the signal discriminating device 20 takes a correlation between the received signal and the replica of the transmission signal, and identifies and separates the desired transmission signal transmitted by itself. The signal processing unit 54 obtains target information and external environment information based on the correlation value obtained by the signal identification unit 53. For example, a bistatic radar device is configured by connecting the radar wave transmitting device and the receiving device shown in FIGS.

  Hereinafter, embodiments of the radar apparatus will be described.

<Embodiment 1: MIMO radar>
FIG. 9 is a diagram illustrating a configuration of the radar apparatus according to the first embodiment. Referring to FIG. 9, the display unit 111, the data processing unit 121, each of which includes a signal generation unit 131-1 to 131-M, a transmission RF (Radio Frequency) unit 132-1 to 132-M, and an antenna unit 133. -1 to 133-M, a plurality of transmission sub-antennas (also referred to as “transmission sub-radars”) # 1 to #M, antenna units 171-1 to 171-N and reception RF units 172-1 to 172, respectively. -N and a plurality of reception sub-antennas (also referred to as “reception sub-radars”) # 1 to #N including signal identification units 173-1 to 173 -N, and a signal processing unit 181. Hereinafter, each part will be described.

  For example, the display unit 111 transmits an instruction from the operator to the data processing unit 121 and displays the data processing result of the data processing unit 121.

  Based on the instruction from the display unit 111 and the processing result (target information and external environment information) from the signal processing unit 181, the data processing unit 121 sends the transmission sub-antennas # 1 to #M (130-1 to 130 -M). Each transmission signal specification is output, the transmission specification of all the transmission sub-antennas is output to each reception sub-antenna (170-1 to 170-N), and the data processing result is output to the signal generation unit 131.

  When the transmission RF units 132-1 to 132-M generate transmission signals (before the RF unit processing) based on the transmission signal specifications of the data processing unit 121, the transmission signals from the signal generation units 131-1 to 131-M are transmitted. Based on (before RF unit processing), the signals are modulated into transmission signals 141-1 to 141-M that can be radiated by the antenna units 133-1 to 133-M (transmission signals from the signal generation units 131-1 to 131-M ( Digital signal) is converted to an analog signal, frequency up-converted, and further power amplified).

  The antenna units 133-1 to 133-M radiate the transmission signals 141-1 to 141-M from the transmission RF units 132-1 to 132-M into the space.

  The antenna units 171-1 to 171-N receive the reception signals 161-1 to 161-N that are spatially synthesized by the transmission signals 141-1 to 141-M being reflected by the target 151 and subjected to Doppler frequency shift.

  The received signals 161-1 to 161-N received by the antenna units 171-1 to 171-N are demodulated into received signals (after RF processing) that can be handled by the signal identifying units 173-1 to 173-N (low noise amplification, Frequency down-converted and converted to digital signal).

  The signal identification units 173-1 to 173 -N, based on each received signal (after RF unit processing) and the transmission specifications of all the transmission sub-antennas from the data processing unit 121, receive signals and all transmissions of each reception sub-antenna. A correlation result with the replica of the transmission signal of the sub-antenna (that is, M correlation results for each reception sub-antenna) is output.

  The signal processing unit 181 calculates a correlation result (that is, M × N correlation results) between each reception signal of each reception subantenna from M reception subantennas and a replica of a transmission signal of N transmission subantennas. Based on this, target information and external environment information are obtained.

  Each of the signal generators 131-1 to 131-M has the configuration of FIG.

  The pseudorandom pattern generator 12 in FIG. 1 is based on the transmission signal specifications of the transmission subantennas from the data processing unit 121 so that the transmission signals between the transmission subantennas have a low correlation, such as an M sequence. Then, a frequency hopping pattern is generated based on the pseudo random sequence. Based on the pattern, the frequency hopping signal generator 11 generates a signal having a waveform (see FIG. 2) whose frequency changes at sub-pulse intervals.

  The sub-pulse chirp modulator 13 shown in FIG. 1 is a chirp in which the frequency in a sub-pulse changes linearly with respect to time with respect to a frequency hopping signal having a constant frequency between the sub-pulses that are output from the frequency hopping signal generator 11. Shape to signal.

<Transmission signal from signal generator>
For example, the signal generators 131-1 to 131-M generate signals as shown in FIG. The transmission signals (before the RF unit processing) generated by the signal generation units 131-1 to 131-M can be expressed as the following equation (1).

・・・（１）

... (1)

here,
t is time,
s _k (t) is a transmission signal of transmission subantenna #k (k = 1,..., M) (before RF section processing),
A _k (t) is the amplitude of transmission subantenna #k (k = 1,..., M),
Fh _k (t) is a frequency hopping pattern of transmission subantenna #k (k = 1,..., M),
Tb _k (t) is a sub-pulse reference time of transmission sub-antenna #k (k = 1,..., M),
Δt is the sub-pulse interval,
Δf is a unit hopping interval.

  FIG. 2 is a diagram illustrating a transmission signal when the number of frequency hopping patterns is five. At this time, the sub-pulse also becomes 5.

A _k (t) in the above equation (1): The amplitude of the transmission sub-antenna #k (k = 1,..., M) is expressed by the following equation (2).

・・・（２）

... (2)

  Here, C is a predetermined constant.

Also, Fh _k (t) in the above formula (1): the frequency hopping pattern. It can be expressed by the following formula (3).

・・・（３）

... (3)

Tb _k (t) in the above equation (1): The sub-pulse reference time of the transmission sub-antenna #k (k = 1,..., M) can be expressed by the following equation (4).

・・・（４）

... (4)

  The transmission RF units 132-1 to 132-M in FIG. 9 modulate the transmission signals (before the RF unit processing) received from the signal generation units 131-1 to 131-M, respectively, and the antenna units 133-1 to 133- Output to M.

  The antenna units 133-1 to 133 -M radiate transmission signals 141-1 to 141 -M, respectively, in space. The transmission signals 141-1 to 141-M are subjected to Doppler frequency shift when reflected on the moving target, synthesized in space, and received by the reception sub-antennas 170-1 to 170-N, respectively. Will arrive. In FIG. 1, for simplicity of the drawing, the target is set to one target, but in general, a composite signal from a plurality of targets is a received signal.

  The antenna units 171-1 to 171-N receive the reception signals 161-1 to 161-N, respectively, and the reception RF units 172-1 to 172-N receive signal identification units 173-1 to 173-N, respectively. Is demodulated to a received signal (after RF processing) and output to the signal identification units 173-1 to 173-N.

<Received signal>
For example, the reception signal (after processing of the RF unit) can be expressed by the following equation (5) in reception from one target. However, the noise component is ignored.

・・・（５）

... (5)

here,
r _l (t) is a reception signal of the reception sub-antenna #l (l = 1,..., N),
A _{l, k} is the amplitude value of the transmission sub-antenna #k (k = 1,..., M) received by the reception sub-antenna #l (l = 1,..., N),
Fh _{l, k} is the frequency hopping pattern of transmission sub-antenna #k (k = 1,..., M) (including the time delay from transmission sub-antenna #k to reception sub-antenna #l),
Tb _{l, k} is the sub-pulse reference time of the transmission sub-antenna #k (k = 1,..., M) (including the time delay from the transmission sub-antenna #k to the reception sub-antenna # 1),
Fd _{l, k} is the Doppler frequency at the reception sub-antenna #l (l = 1,..., N) of the transmission signal from the transmission sub-antenna #k (k = 1,..., M),
Δt is the sub-pulse interval,
Δf is the unit hopping interval,
It is.

  The signal identification units 173-1 to 173 -N extract each transmission signal component from the reception signal based on each reception signal (after the RF unit processing) and transmission specifications of all transmission sub-antennas from the data processing unit 121. .

<Signal Identification Unit of Embodiment 1>
FIG. 10 is a diagram illustrating the configuration of each of the signal identification units 173-1 to 173 -N in FIG. 9. Referring to FIG. 10, a Fourier transformer 311 that converts each received signal (after RF section processing) demodulated by the reception RF units 172-1 to 172-N from a time domain signal to a frequency domain signal, An information manager 331 and signal identification blocks # 1 (320-1) to #M (320-M) are provided corresponding to the transmission sub-antennas # 1 to #M in FIG.

  The signal identification blocks # 1 (320-1) to #M (320-M) generate reference signals (replicas of desired transmission signals) based on the transmission signal specifications of the transmission subantennas from the information manager 331. The signal generators 323-1 to 323-M and the Fourier transformer 324-1 for converting the time domain reference signals (replicas of desired transmission signals) generated by the signal generators 323-1 to 323-M into the frequency domain. 324-M, the frequency domain reception signal output from the Fourier transformer 311 and the time domain transmission signal from the signal generators 323-1 to 323-M, respectively. And a correlation processor 321-1 to 321-M for performing a complex multiplication on the reference signal (replica of a desired transmission signal) converted into the frequency domain by the And a inverse Fourier transformer 322-1 to 322-M convert the region.

The Fourier transformer 311 uses the time domain received signal (after RF processing) r _l (t) of the above equation (5) as the received signal of the received sub-antenna #l (l = 1,..., N) as the frequency. The signal is converted into a region signal R _l (f) and output to the correlation processors 321-1 to 321-M.

  The information manager 331 divides the transmission signal specifications of all the transmission sub-antennas received from the data processing unit 121 in advance into the transmission signal specifications of the respective transmission sub-antennas, and the corresponding signal identification block # 1 (320-1). ~ Output to signal identification block #M (320-M).

  The signal generators 323-1 to 323 -M receive the transmission signal specifications of the transmission subantennas output from the information manager 331, and in the same way as the signal generators 131-1 to 131 -M of FIG. A replica of the transmission signal represented by 1) is created and output to the Fourier transformers 324-1 to 324-M.

In the Fourier transformers 324-1 to 324-M, the replica of the transmission signal in the time domain of the above equation (5) is converted into the signal S _k (f) in the frequency domain.

In the correlation processors 321-1 to 321-M, the frequency domain signal R _l (f) from the Fourier transformer 311 and the complex of S _k (f) from the Fourier transformers 324-1 to 324-M, respectively. Complex multiplication with conjugate-transformed S _k ^* (f) is performed.

・・・（６）

... (6)

  By the above calculation, frequency hopping for each sub-pulse is applied to the transmission signal so that the transmission signals from each transmission sub-antenna have low correlation with each other, and a sufficient chirp modulation band is provided even if subjected to Doppler frequency shift. A high correlation with the reference signal (a replica of the transmission signal) is maintained (so that it does not become 0 or a value close to 0).

Therefore, output signals (frequency domain) Z _{l, k} (f) (l = 1,..., N, k = 1,..., M) of the correlation processors 321-1 to 321-M A received signal that has received the Doppler frequency due to reflection can be correlated with only a required transmission signal.

Inverse Fourier transformers 322-1 to 322 -M respectively convert frequency domain signals Z _{l, k} (f) into time domain signals z _{l, k} (t), which are received by receiving subantenna #l. Is output to the information manager 331 as a correlation result with the transmission signal replica of the transmission sub-antenna #k (k = 1,..., M).

  The information manager 331 synchronizes the correlation results with the transmission signal replicas of the transmission sub-antennas of the signal identification blocks # 1 to #M, and all the transmission sub-antennas #k (k = 1, ..., M) is output to the signal processing unit 181 as a correlation result with the replica of the transmission signal.

  The signal processing unit 181 in FIG. 9 receives the correlation results with the replicas of the transmission signals #k (k = 1,..., M) of all the transmission sub-antennas from each of the signal identification units 173-1 to 173-N. For this reason, the signal processing unit 181 receives M × N correlation results from the signal identification units 173-1 to 173-N.

  The signal processing unit 181 performs MIMO radar signal processing on the M × N correlation results, and outputs target information and external environment information to the data processing unit 121. For MIMO radar signal processing, known methods such as various texts are used (for example, Jian Li, Petre Stoica, “MIMO Radar Signal Processing”, John Wiley & Sons, Inc., October 2008). Etc.).

  In the signal processing unit 181, in the MIMO radar signal processing, M × N correlation results are obtained, which is virtually equivalent to receiving signals with M × N antennas.

  The signal processing unit 181 can virtually increase the antenna opening length by appropriately weighting each correlation result. As a result, a high azimuth resolution can be obtained with respect to the target. This is one of the well-known features of MIMO radar. In the MIMO radar, the beam synthesis is performed by the signal processing unit 181.

<Effect of Embodiment 1>
In the first embodiment, in addition to the operational effect of the basic concept of the present invention described above, there is an operational effect that a high azimuth resolution can be obtained for a target which is one of the features of the MIMO radar.

<Embodiment 2: Frequency sharing radar>
FIG. 11 is a diagram illustrating the configuration of the second exemplary embodiment of the present invention. In order to avoid interference with signals transmitted from other radar devices, a plurality of closely spaced radar devices sharing a frequency are transmitted with low correlation to each other. Referring to FIG. 11, a plurality (K) of radars # 1 to #K (510-1 to 510-K) include display units 511-1 to 511-K and data processing units 512-1 to 512, respectively. -K, signal generation units 513-1 to 513-K, transmission / reception RF units 514-1 to 514-K, antenna units 515-1 to 515-K, and beam combining units 516-1 to 516-K , Signal identification units 517-1 to 517-K and signal processing units 518-1 to 518-K.

  When the configuration of FIG. 11 is compared with the first embodiment shown in FIG. 9, the first embodiment of FIG. 9 has a configuration in which transmission and reception are separated, but in FIG. The unit 515 and the transmission / reception RF unit 514 are integrated with each other. The signal generation unit 513 has the same configuration as that of FIG. 9 except that a process of transmitting a transmission signal replica to the signal identification unit 517 is added, and generates a transmission signal having a waveform as shown in FIG. Let

  In the first embodiment, a plurality of antenna units (133-1 to 133-M and 171-1 to 171-) are used for one display unit 111, one data processing unit 121, and one signal processing unit 181. N) is configured to handle the result. On the other hand, in the second embodiment, radars # 1 to #K (510-1 to 510-K) have independent configurations. Therefore, the result of one antenna unit 515 is handled for one display unit 511, one data processing unit 512, and one signal processing unit 518.

  In the first embodiment, the information manager 331 of the signal identification unit 173 needs to collect the received signals in synchronization. In contrast, in the signal identification unit 517 of the second embodiment, an information manager is not required. Further, all transmission signal specifications are not required, and the signal generation unit 513 sends a replica of the transmission signal to the signal identification unit 517, so that the signal identification unit 173 of the first embodiment in FIG. The provided signal generator 323 becomes unnecessary.

  The signal identification unit 517 of the second embodiment is configured as shown in FIG. 4, and is a process for identifying and separating only the signal transmitted by the own radar. The signal processing in the signal processing unit 518 also does not perform processing unique to the MIMO radar. The beam combining unit 516 is required when performing beam combining at the antenna unit in a digital stage. However, when analog synthesis is performed by the transmission / reception RF unit 514, the beam synthesis unit 516 is not necessary. In the MIMO radar of FIG. 9, beam synthesis is performed by the signal processing unit 181.

  Generation of a low-correlation pattern between radars # 1 to #K that operate independently of each other is performed asynchronously using only predetermined low-correlation patterns in the data processing units 512-1 to 512-K. May be.

  Further, if leakage of transmission signals from other radars at the time of reception becomes a problem, for example, in the data processing units 512-1 to 512 -K, for example, a pseudo random code from a GPS (Global Positioning System) satellite. May be received to synchronize the transmission timing or generate a pseudo random number pattern.

<Effects of Second Embodiment>
According to the second embodiment, with respect to a plurality of closely arranged radars sharing a frequency, interference with a signal transmitted from another radar device is avoided from a received signal shifted by Doppler frequency due to reflection from a moving target. The desired transmission signal can be identified and separated.

<Embodiment 3>
FIG. 12 is a diagram for explaining a third embodiment of the present invention. The third embodiment is an embodiment in which the signal generation according to the present invention is applied to the secondary echo described with reference to FIG. The third embodiment has a single radar configuration.

  Referring to FIG. 12, the radar 610 includes a display control unit 611, a data processing unit 612, a signal generation unit 613, a transmission / reception RF unit 614, an antenna unit 615, a beam combining unit 616, and a signal identification unit 617. And a signal processing unit 618. Each part will be described below.

  The display control unit 611 transmits an instruction from the operator to the data processing unit 612 and displays the data processing result of the data processing unit 612.

  The data processing unit 612 outputs transmission signal specifications based on an instruction from the display control unit 611 and a processing result (target information and external environment information) from the signal processing unit 618, and also outputs a data processing result to the signal processing unit 618. Is output.

  The signal generation unit 613 is configured as shown in FIG. 1, for example, generates a transmission signal (before RF processing) based on the transmission signal specifications of the data processing unit 612, and outputs a transmission signal replica to the signal identification unit 617.

  The transmission / reception RF unit 614 modulates the transmission signal (before RF processing) of the signal generation unit 613 into a transmission signal that can be emitted by the antenna unit 615.

  The antenna unit 615 radiates the transmission signal from the transmission / reception RF unit 614 to the space, reflects the signal that has been reflected by the target within the observation range and has undergone Doppler frequency shift, and the pulse transmitted immediately before from the outside of the observation range. A received signal obtained by combining the signal reflected by the target and the clutter and subjected to the Doppler frequency shift is received.

  The transmission / reception RF unit 614 receives and amplifies and demodulates the reception signal received by the antenna unit 615.

  The beam combining unit 616 receives the output of the transmission / reception RF unit 614 that receives the reception signal from the antenna unit 615, and performs beam combining at the digital stage.

  The signal identification unit 617 has the configuration shown in FIG. 4, and correlates the received signal synthesized by the beam synthesis unit 616 with the replica of the transmission signal from the signal generation unit 613, and reflects it to the target within one observation range. Only signals that have undergone Doppler frequency shift are identified and separated.

  The signal processing unit 618 obtains target information and external environment information based on the correlation value obtained by the signal identification unit 617.

  The signal generator 613 generates a transmission signal as shown in FIG. However, in the signal generator 613, as shown in FIG. 15, the waveforms shown in FIG. 3 are used as the pulses to be transmitted at the even number (2X) times and the pulses to be transmitted at the odd number (2X + 1) times, thereby reducing each other. Send as correlation.

  Thus, the signal identification unit 617 can correlate only the replica of the transmission signal and the reflected signal from within the observation range.

  In addition, reflection signals of targets and clutter from outside the observation range are suppressed. For this reason, it can be seen that it is possible to take measures against the secondary echo even for the received signal subjected to the Doppler frequency shift due to the reflection from the moving target. It is possible to use not only the secondary echo but also the P-order echo (P is 2 or more). In this case, it is necessary to prepare P low-correlated waveforms.

<Effect of Embodiment 3>
According to the third embodiment, in addition to the effects of the basic concept of the present invention described above, it is possible to take measures against secondary echo even for a received signal that has undergone Doppler frequency shift due to reflection from a moving target. It has the effect of being.

<Embodiment 4>
The basic configuration of the fourth embodiment is the same as FIG. 12 referred to in the description of the third embodiment. In the fourth embodiment, for example, for a plurality of targets having different azimuths as shown in FIG. 14A, transmission signals having low correlation are continuously transmitted to each target before reception.

  Based on the information from the data processing unit 612, the signal generation unit 613 in FIG. 12 applies each beam # 1 to #Y to a plurality of targets # 1 to #Y having different directions as shown in FIG. Are transmitted as low-correlation transmission signals with respect to each target as shown in FIG. 3 before receiving the respective transmission signals. Replicas of transmission signals of the beams # 1 to #Y are output to the signal identification unit 617.

<Signal Identification Unit of Embodiment 4>
The antenna unit 615 receives a Doppler frequency shift due to reflection from each moving target and receives a reception signal synthesized in space. In the signal identification unit 617, it is necessary to identify and separate which target the beam transmission signal is directed to.

  For this reason, the signal identification part 617 is configured as shown in FIG. 13, for example. In FIG. 13, a Fourier transformer 1411 converts a radar reception signal into a frequency domain signal and outputs the signal to the correlation processors 1421-1 to 1421-Y of the signal identification blocks # 1 to #Y. Replicas of the transmission signals of beam # 1 to beam #Y from the signal generation unit 613 are input to Fourier transformers 1422-1 to 1422-Y, respectively. In the Fourier transformers 1422-1 to 1422-Y, the replicas of the transmission signals in the time domain of the beams # 1 to #Y are converted into signals in the frequency domain (the above formula (5)).

  In the correlation processors 1421-1 to 1421-Y, complex multiplications of signals in the frequency domain from the Fourier transformer 1411 and signals obtained by complex conjugate transformation of the signals from the Fourier transformers 1422-1 to 1422-Y ( The above formula (6) is performed.

  By the above calculation, frequency hopping for each sub-pulse is applied to the transmission signal so that the transmission signals from each transmission sub-antenna have low correlation with each other, and a sufficient chirp modulation band is provided even if subjected to Doppler frequency shift. A high correlation with the reference signal (a replica of the transmission signal) is maintained (so that it does not become 0 or a value close to 0).

  For this reason, the output signals (frequency domain) of the correlation processors 1421-1 to 1421-Y are only required transmission signals even for reception signals that have received the Doppler frequency due to reflection from the movement targets # 1 to #Y. Can be correlated.

  Inverse Fourier transformers 143-1 to 1423-Y convert the output signals (frequency domain) of correlation processors 1421-1 to 1421-Y into time domain signals, which are converted into movement targets # 1 to #Y. Is output as a correlation result between the reception signal reflected from and the replica of the transmission signal.

  The signal transmitted from the signal generator 613 toward each of the targets # 1 to #Y has the waveform shown in FIG. 3, and identifies a desired transmission signal from the reception signal subjected to the Doppler frequency shift, Can be separated.

  For this reason, even if a plurality of targets having different azimuths are transmitted to a plurality of targets having different azimuths continuously before transmission, they are reflected on the moving target and subjected to Doppler frequency shift and combined in space. It can be seen that the required transmission signal can be identified and separated.

<Effect of Embodiment 4>
According to the fourth embodiment, in addition to the operational effects of the basic concept of the present invention described above, transmission signals that are continuously low-correlated to each target are transmitted to a plurality of targets having different azimuths before reception. As a result, even if each of the signals is reflected on the moving target and subjected to the Doppler frequency shift and synthesized in space, the required transmission signal can be identified and separated.

<Modification 1 of Embodiment 1-4>
In the signal generators 131, 513, and 613 of Embodiment 1-4 described with reference to FIG. 9, FIG. 11, and FIG. 12, the frequency of the transmission signal of each transmission sub-antenna does not overlap in each sub-pulse. Although it is divided into M subpulses (that is, the number of divisions of the band is also M), the number of subpulse divisions is of course not limited to M.

  For example, the number of sub-pulse divisions may be smaller than M. In this case, although the cross-correlation characteristics between the transmission signals are deteriorated, it is possible to increase the bandwidth allocated to one when reducing the necessary frequency bandwidth or dividing the frequency bandwidth. Or you may make the division | segmentation number of a frequency band larger than M. However, in this case, it is necessary to increase the necessary frequency bandwidth or reduce the bandwidth allocated to one when dividing the frequency bandwidth.

  In the first embodiment, the transmission sub-antenna and the reception sub-antenna are configured separately, but a transmission / reception integrated sub-antenna that can be switched between transmission and reception may be used. In the case of a sub-antenna integrated with transmission and reception, the antenna part of the transmission sub-antenna and the reception sub-antenna are integrated, and the transmission RF part at the front stage of the antenna part and the reception RF part at the rear stage are combined into one body by adding a switch. It is replaced with a transmission / reception RF unit.

  In the second, third, and fourth embodiments, the configuration in which transmission and reception are integrated is opposite to the above, and transmission and reception may be separately performed. A configuration having separate antenna portions for transmission and reception makes it possible to arrange the transmission position and the reception position differently. You can always receive while sending. However, it is necessary to consider leakage of the transmission signal at the time of reception. On the other hand, in the case of a transmission / reception integrated configuration, reception is not possible during transmission, but space can be used effectively.

<Modification 2 of Embodiment 1-4>
In the signal generation units 131, 513, and 613 of the embodiment 1-4 described with reference to FIGS. 9, 11, and 12, signals are not generated in the system as shown in FIG. 2, but are shown in FIG. It is good also as a structure which generates a signal by such a system | strain. In FIG. 2, linear chirp modulation is performed between subpulses on a frequency hopping waveform, whereas in FIG. 7, chirp modulation between pulses is created by a chirp signal generator 31, and subpulses are divided by a subpulse divider 32. The same waveform as in FIG. 2 is generated by rearranging based on the frequency hopping pattern generated by the pseudo random number pattern generator 34.

<Modification 3 of Embodiment 1-4>
In the signal generation units 131, 513, and 613 of Embodiment 1-4 described with reference to FIGS. 9, 11, and 12, the guard band band as shown in FIG. 5 is used instead of the waveform as shown in FIG. Use the provided waveform. In the waveform of FIG. 2, the waveform subjected to the Doppler frequency shift has poor autocorrelation and cross-correlation characteristics due to interference with different frequency bands. As a workaround, a waveform having a guard band band corresponding to the assumed Doppler frequency shift is used as shown in FIG. Instead of avoiding interference, it is necessary to reduce the bandwidth of chirp modulation or increase the bandwidth to be used. However, in the former case, the gain at the time of correlation is low, and in the latter case, there is a waste in use in terms of bandwidth.

<Modification 4 of Embodiment 1-4>
In the signal generators 131, 513, and 613 of the embodiment 1-4 described with reference to FIGS. 9, 11, and 12, chirps having different slopes as shown in FIG. 6 instead of the waveforms as shown in FIG. It is good also as a waveform which combined the signal continuously. In order to avoid interference in different frequency bands when subjected to Doppler frequency shift, interference is reduced by making the chirp slopes of the interference portions different. Compared with the case where a guard band is provided, the effect of avoiding interference is low, but it is not necessary to narrow the bandwidth of chirp modulation or increase the bandwidth to be used.

  In FIG. 6, the subpulses are divided into two and have different slopes, but the subpulses may be divided into a plurality of slopes, and the slopes may be different for each. However, since the sub-pulses are divided, the frequency modulation switching speed is increased.

  In the signal identification units 173, 517, and 617 of Embodiment 1-4 described with reference to FIGS. 9, 11, and 12, in addition to using a replica of the transmission signal as a reference signal, a fixed Doppler is provided in parallel. A signal identification unit (173, 517, 617) that performs correlation processing using a replica of the transmission signal to which the frequency shift is added may be used. While reduction of the correlation gain due to the Doppler frequency shift can be avoided, the processing load increases.

<Contrast between embodiment and related technology>
The present invention (the basic concept thereof) described with reference to FIG. 1 and the like, the embodiment of the present invention described above, and related technology (for example, Patent Document 1) will be described in comparison. In Patent Document 1, in order to make the correlation between transmission signals low, based on the phase modulation pattern for each transmission subantenna, as described with reference to FIG. 16A, it is proportional to the square of time within the subpulse. A multi-level phase code signal to which the phase rotation is given is generated.

  Further, in Patent Document 1, an N-bit reference code having a chip length τ is repeatedly used in M subpulses of each transmission subradar. Generation of ambiguity is suppressed by multiplying a signal obtained by repeating M N-bit reference codes by a signal waveform of linear frequency modulation (chirp modulation).

  At this time, in order to increase the effect of maintaining the correlation by repeating the code (phase code modulation), in order to increase the shift amount of the code component along the chirp modulation slope with respect to the assumed Doppler frequency shift, The bandwidth of chirp modulation is set narrow. The frequency bandwidth of the chirp modulation (frequency modulation width) is, for example, about several times the assumed Doppler frequency shift, and the gradient of the chirp modulation is gentler than that of the present embodiment.

  FIG. 16B is a diagram schematically showing an example in which the transmission signal subjected to the Doppler frequency shift matches the repeated part of the code in the sub-pulse of the replica of the desired transmission signal in Patent Document 1 (the present invention). This is a drawing drawn by a person and is not in Patent Document 1). As shown in FIG. 16B, one pulse is composed of five subpulses, the assumed Doppler frequency shift is ΔfDoppler, the subpulse width is Δt, the frequency band of the chirp modulation is 2.5ΔDoppler, and the slope is therefore 2.5ΔfDoppler. / (5Δt), the code component of the transmission signal subjected to the Doppler frequency shift = ΔfDoppler is time t = ΔfDoppler / (2.5ΔfDoppler / (5Δt)) = 2Δt, that is, two sub-pulse widths, time axis Shifting up and down matches the subpulse sign of the replica of the transmission signal.

  On the other hand, in Patent Document 1, when the frequency bandwidth of the chirp modulation (chirp modulation slope) is increased, the code component of the transmission signal subjected to the Doppler frequency shift is repeated on the time axis in the code repetition portion of the transmission signal replica. No longer shifts. That is, the signal that has undergone the Doppler frequency shift does not overlap with the repeated portion of the code of the replica of the transmission signal, and the meaning of repeating the code within the subpulse is lost.

  In Patent Document 1, since code modulation is performed within a subpulse and the code is repeated for each subpulse, the strength of the code correlation between the received signal subjected to the Doppler frequency shift and the transmission signal is periodically increased due to the Doppler frequency shift. Become weak or weak. At this time, due to the correlation characteristics of the code, the way of generating the correlation is non-linear, and there is a case where the correlation is hardly obtained.

  On the other hand, according to the embodiment of the present invention, by applying chirp modulation with a sufficient bandwidth to the assumed Doppler frequency shift, the correlation due to the chirp modulation is linear with respect to the Doppler frequency shift. The amount of decrease is also very small.

  Further, since the embodiment of the present invention does not generate a signal that repeats the same code as in Patent Document 1, the cross-correlation characteristics of an apparently new code sequence appearing by repeating the code. Deterioration is avoided.

  Furthermore, according to the present invention described with reference to FIG. 1 and the like, the frequency hopping is performed at the subpulse interval Δt. For this reason, when the pulse width T is the same as that in Patent Document 1, the modulation switching speed is slower in the embodiment of the present invention than in Patent Document 1. As a result, the circuit / device configuration can be simplified. In the embodiment of FIG. 1, frequency modulation is performed at subpulse width intervals, whereas in Patent Document 1, it is necessary to perform code modulation with a chip length obtained by dividing the subpulse width by the number N of receiving subantennas. Because.

  An example will be described in which a near-field target 1 km away is viewed with a radar that does not receive during transmission (operation necessary for a radar in which interference caused by leakage from a transmission signal during reception) is a problem. Since a signal reflected during transmission cannot be received, for example, when it is desired to see a target 1 km away, the maximum pulse width is about 3 μs (micro second). When the number of transmission sub-antennas and the number of reception sub-antennas are both 10 under additional conditions, the frequency modulation switching speed in the embodiment is 3 MHz (MegaHerz), whereas in Patent Document 1, phase code modulation is used. The switching speed is 30 MHz. The speed required for switching the modulation is lower in the embodiment. For this reason, the circuit configuration is facilitated.

  Further, when the circuit configurations are compared with each other, and therefore, when the modulation switching speed is the same, the required pulse width is shorter than the signal of Patent Document 1 according to the embodiment. For this reason, when compared with a radar that does not receive at the time of transmission, according to the embodiment, it becomes possible to detect a target at a shorter distance. If the switching speed of modulation is the same, Patent Document 1 has a longer pulse width than that of the embodiment, making it difficult to detect a short-range target.

  It should be noted that the disclosures of the above-mentioned patent documents and non-patent documents are incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) are possible within the scope of the claims of the present invention. . That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

DESCRIPTION OF SYMBOLS 10, 30 Signal generator 11 Frequency hopping signal generator 12 Pseudo random pattern generator 13 Intra-sub-pulse chirp modulator 20 Signal discriminator 21, 24 Fourier transformer 22 Correlator 23 Inverse Fourier transformer 31 Chirp signal generator 32 Sub-pulse Divider 33 Sub-pulse rearranger 34 Pseudo-random pattern generator 40 Transmitter 41 Signal generator 42 Transmit RF unit 43 Antenna unit 50 Receiver unit 51 Antenna unit 52 Receive RF unit 53 Signal identification unit 54 Signal processing unit
111 Display Unit 121 Data Processing Unit 130 Transmission Sub-antenna 131 Signal Generation Unit 132 Transmission RF Unit 133 Antenna Unit 141 Transmission Signal 151 Target 161 Reception Signal 170 Reception Sub-Antenna 171 Antenna Unit 172 Reception RF Unit 173 Signal Identification Unit 181 Signal Processing Unit 311 Fourier Transformer 320 Signal Identification 321 Correlation Processor 322 Inverse Fourier Transformer 323 Signal Generator 324 Fourier Transformer 331 Information Manager 510 Radar 511 Display Unit 512 Data Processing Unit 513 Signal Generation Unit 514 Transmission / Reception RF Unit 515 Aerial Line Unit 516 Beam Synthesis Unit 517 signal identification unit 518 signal processing unit 610 radar 611 display control unit 612 data processing unit 613 signal generation unit 614 transmission / reception RF unit 615 antenna unit 616 beam combining unit 617 signal identification unit 618 signal processing unit 1011 pseudo Random number pattern generator 1021 Intra-sub-phase phase code modulation signal generator 1031 Sub-pulse repetition processor 1041 In-pulse chirp modulator 1411 Fourier transformer 1420 Signal identification 1421 Correlation processor 1422 Fourier transformer 1423 Inverse Fourier transformer

Claims (24)

  The sub-pulses obtained by dividing the pulse into a plurality are chirp modulated with a predetermined frequency bandwidth, and a signal in which the order of the time series of the frequency band for each sub-pulse is almost random is generated. A featured signal generator. Means for generating a pseudo-random pattern;
Means for hopping the frequency according to the pseudo-random pattern for each sub-pulse;
Means for applying chirp modulation with a predetermined frequency bandwidth within the sub-pulse;
The signal generator according to claim 1, further comprising: Means for subjecting the pulse to chirp modulation at a predetermined frequency bandwidth determined in advance;
Means for dividing the pulse into a plurality of sub-pulses on a time axis;
Means for generating a pseudo-random pattern;
Means for rearranging the order of the sub-pulses according to the pseudo-random pattern for each sub-pulse;
The signal generator according to claim 1, further comprising:   The signal generator according to claim 1, wherein a guard band band is provided for each sub-pulse.   4. The signal generating apparatus according to claim 2, wherein said chirp modulation means generates a signal in which a plurality of waveforms having different chirp modulation slopes are combined in said sub-pulse.   The signal generator according to claim 1, wherein the predetermined frequency bandwidth is a bandwidth that sufficiently covers an assumed Doppler frequency shift. A signal obtained by modulating a transmission signal generated by the signal generator according to any one of claims 1 to 6 and receiving a Doppler frequency shift by reflecting a signal radiated to the space via the antenna and reflecting to a target. A signal identification device for identifying a received signal demodulated through reception,
Characterized in that it comprises means for converting the received signal into a frequency domain, calculating a phase with a signal obtained by converting a replica of the transmission signal into a frequency domain, and converting the phase result into a time domain and outputting it. Signal identification device. A display unit;
A data processing unit;
A plurality of transmission sub-antennas each including a signal generation unit, a transmission RF unit, and an antenna unit;
A plurality of reception sub-antennas each including an antenna unit, a reception RF unit, and a signal identification unit;
A signal processing unit;
With
The display unit transmits the input instruction information to the data processing unit and displays the data processing result of the data processing unit,
The data processing unit outputs transmission signal specifications to each transmission sub-antenna based on an instruction from the display unit and a processing result from the signal processing unit, and sets transmission specifications of the plurality of transmission sub-antennas. Output to each of the receiving sub-antennas, and further output a data processing result to the signal processing unit,
In each of the transmission sub-antennas,
The signal generation unit includes the signal generation device according to any one of claims 1 to 6, and generates a transmission signal based on transmission signal specifications of the data processing unit,
The transmission RF unit modulates the transmission signal from the signal generation unit into a transmission signal that can be radiated by the antenna unit,
The antenna unit radiates the transmission signal from the transmission RF unit to space,
In each receiving sub-antenna,
The antenna unit receives a reception signal synthesized by receiving a Doppler frequency shift by reflecting the transmission signal from each transmission sub-antenna to a target,
The reception RF unit demodulates the reception signal received by the antenna unit into a reception signal that can be handled by the signal identification unit,
The signal identification unit, based on the transmission signal of the plurality of transmission sub-antennas from the reception signal and the data processing unit, from the reception signal of each reception sub-antenna, a replica of the transmission signal of the plurality of transmission sub-antennas Output the correlation result with
The radar apparatus, wherein the signal processing unit obtains target information and external environment information based on the correlation results from the plurality of reception sub-antennas. The signal identification unit is
A first means for converting a reception signal from the reception RF section into a frequency domain;
A plurality (M) of signal identification blocks corresponding to the plurality of transmission sub-antennas;
An information management department;
With
The i-th (i = 1 to M) signal identification block is
means for generating a replica of the transmission signal from the signal generation unit of the i-th transmission sub-antenna based on the transmission signal specifications of the i-th transmission sub-antenna;
Means for calculating a phase between the received signal converted into the frequency domain by the first means and a signal obtained by converting a replica of the transmission signal from the signal generation unit of the i-th transmission subantenna into the frequency domain;
Means for converting the interphase results into a time domain and outputting them;
With
The information management unit receives transmission signal specifications of the plurality of transmission sub-antennas from the data processing unit, and supplies transmission signal specifications of each transmission sub-antenna to the corresponding signal identification blocks; The radar apparatus according to claim 8, wherein: In each of multiple radars that share frequency and are closely located,
A display unit;
A data processing unit;
A signal generator;
A transmission / reception RF unit;
The antenna part,
A beam combiner;
A signal identification unit;
A signal processing unit;
With
The display unit transmits the input instruction information to the data processing unit, displays the data processing result of the data processing unit,
The data processing unit outputs a transmission signal specification based on an instruction from the display unit and a processing result from the signal processing unit, and further outputs a data processing result to the signal processing unit,
The signal generation unit includes the signal generation device according to any one of claims 1 to 6, and generates a transmission signal based on transmission signal specifications of the data processing unit, and further to the signal identification unit Outputting a replica of the transmitted signal;
The transmission / reception RF unit modulates the transmission signal from the signal generation unit into a transmission signal that can be radiated by the antenna unit,
The antenna unit radiates a transmission signal from the transmission / reception RF unit to the space, and receives a reception signal synthesized by receiving a Doppler frequency shift by reflecting the transmission signal from each antenna unit of each radar to a plurality of targets. And
The transmission / reception RF unit demodulates a reception signal received by the antenna unit,
The beam combining unit beam combines the received signals from the transmission / reception RF unit,
The signal identification unit calculates a correlation between the received signal beam synthesized by the beam synthesis unit and a replica of the transmission signal from the signal generation unit,
The radar apparatus, wherein the signal processing unit obtains target information and external environment information based on the correlation value calculated by the signal identification unit. A display control unit;
A data processing unit;
A signal generator;
A transmission / reception RF unit;
The antenna part,
A beam combiner;
A signal identification unit;
A signal processing unit;
With
The display control unit transmits the input instruction information to the data processing unit, displays the data processing result of the data processing unit,
The data processing unit outputs a transmission signal specification based on an instruction from the display unit and a processing result from the signal processing unit, and outputs a data processing result to the signal processing unit,
The signal generation unit includes the signal generation device according to claim 1, generates a transmission signal based on transmission signal specifications of the data processing unit, and further transmits the transmission signal to the signal identification unit. Outputs a replica of the signal,
The transmission / reception RF unit modulates the transmission signal from the signal generation unit into a transmission signal that can be radiated by the antenna unit,
The antenna unit radiates the transmission signal from the transmission / reception RF unit to the space, reflects the signal reflected by the target within the observation range and undergoes a Doppler frequency shift, and a pulse transmitted one before from the outside of the observation range. Receive the received signal that is synthesized with the signal reflected by the target and clutter and subjected to the Doppler frequency shift,
The transmission / reception RF unit demodulates a reception signal received by the antenna unit,
The beam combining unit beam combines the received signals from the transmission / reception RF unit,
The signal identification unit calculates a correlation between the received signal beam synthesized by the beam synthesis unit and a replica of the transmission signal from the signal generation,
The radar apparatus, wherein the signal processing unit obtains target information and external environment information based on the correlation value calculated by the signal identification unit. The signal generation unit generates transmission signals of a plurality of (Y) beams having a low phase with respect to a plurality of (Y) targets having different directions,
The signal identification unit is
A first means for converting a reception signal from the reception RF section into a frequency domain;
A plurality of (Y) signal identification blocks corresponding to the plurality of beams;
With
The i th (i = 1 to Y) signal identification block is:
Means for calculating the phase between the signal converted into the frequency domain by the first means and the signal converted from the replica of the transmission signal of the i-th beam from the signal generator into the frequency domain;
12. The radar apparatus according to claim 11, further comprising means for converting the interphase result into a time domain and outputting the result.   The sub-pulses obtained by dividing the pulse into a plurality are chirp modulated with a predetermined frequency bandwidth, and a signal in which the order of the time series of the frequency band for each sub-pulse is almost random is generated. A characteristic signal generation method. Hopping frequency according to the pseudo-random pattern for each sub-pulse,
14. The signal generation method according to claim 13, wherein chirp modulation is performed in a predetermined frequency bandwidth predetermined within the sub-pulse. Chirp modulation with a predetermined frequency bandwidth predetermined for the pulse,
Dividing the pulse into a plurality of sub-pulses on the time axis;
The signal generation method according to claim 13, wherein the order of the sub-pulses is rearranged according to a pseudo-random pattern for each sub-pulse.   The signal generation method according to claim 13, wherein a guard band is provided for each sub-pulse.   The signal generation method according to claim 13, wherein a signal in which a plurality of waveforms having different chirp modulation slopes is combined in the sub-pulse is generated.   18. The signal generation method according to claim 13, wherein the predetermined frequency bandwidth is a bandwidth that sufficiently covers an assumed Doppler frequency shift. A signal obtained by modulating a transmission signal generated by the signal generation method according to any one of claims 13 to 18 and reflecting a signal radiated to the space through the antenna to a target and receiving a Doppler frequency shift is transmitted to the antenna. A signal identification method for identifying a received signal demodulated through reception,
A signal identification method comprising: converting the received signal into a frequency domain; calculating a phase with a signal obtained by converting a replica of the transmission signal into a frequency domain; and converting the phase result into a time domain and outputting the result. .   A computer that generates a signal in which a sub-pulse obtained by dividing a pulse into a plurality of signals is chirp modulated with a predetermined frequency bandwidth that is determined in advance, and a time-series sequence of the frequency bands for each sub-pulse is almost random. A program to be executed. Processing to generate a pseudo-random pattern;
Hopping frequency according to the pseudo-random pattern for each sub-pulse;
A process of performing chirp modulation with a predetermined frequency bandwidth determined in advance in the sub-pulse;
21. The program according to claim 20, wherein the program is executed by the computer. A process of performing chirp modulation with a predetermined frequency bandwidth on the pulse;
A process of dividing the pulse into a plurality of sub-pulses on the time axis;
Processing to generate a pseudo-random pattern;
For each subpulse, the process of rearranging the order of the subpulses according to the pseudo-random pattern;
21. The program according to claim 20, wherein the program is executed by the computer.   The program according to any one of claims 20 to 22, wherein the predetermined frequency bandwidth is a bandwidth that sufficiently covers an assumed Doppler frequency shift. A signal obtained by modulating a transmission signal generated by the program according to any one of claims 20 to 23 and receiving a Doppler frequency shift by reflecting a signal radiated to the space via the antenna and reflecting to the target via the antenna. A process of identifying a received signal demodulated
A program for causing a computer to execute a process of converting the received signal into a frequency domain, calculating a phase with a signal obtained by converting a replica of the transmission signal into a frequency domain, converting the interphase result into a time domain, and outputting the result.

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