JP2022073325A - Radar device - Google Patents

Abstract

To obtain a radar device with which it is possible to perform distance measurement with high accuracy without using information that pertains from a platform.SOLUTION: A radar device 100 comprises a transmit pulse generation unit 1, a first frequency conversion unit 4, and a plurality of second frequency conversion units 60, 61, 62, ..., 6n. The transmit pulse generation unit 1 generates, using a plurality of signals for frequency conversion, with frequency shifted in units of predetermined step frequency in a pulse repetition period, a plurality of transmit pulse signals which are shifted in units of the step frequency in the pulse repetition period. The first frequency conversion unit 4 converts the frequencies of a plurality of receive pulse signals on the basis of the plurality of signals for frequency conversion and a local signal. The plurality of second frequency conversion units 60, 61, 62, ..., 6n shift the frequencies of a plurality of signals which are the plurality of receive pulse signals having been frequency converted by the first frequency conversion unit 4 by a frequency which is an integral multiple of the step frequency and mutually different.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a radar device mounted on a moving platform such as a flying object and receiving a reflected wave by a target of a pulsed radio wave radiated into space to detect the target.

Conventionally, as a method for detecting a target in a radar device, a low pulse repetition (LPRF) method, a medium pulse repetition (MPRF) method, and a high pulse repetition (High Pulse Repetition Frequency: HPRF) method are used. The method is known.

In the LPRF method, the time from the transmission of the radio wave to the reception of the radio wave reflected by the target is sufficiently secured for the round-trip distance to the target. On the other hand, in the MPRF method and the HPRF method, the pulse repetition period (PRI) is shortened as compared with the LPRF method in order to improve the performance of detecting the target and acquire the speed information of the target. ..

In Patent Document 1, frequency conversion is performed using a frequency synthesizer for each of a plurality of received pulse signals output from the antenna device based on the distance information from the platform, and the plurality of signals after frequency conversion are subjected to frequency conversion. A HPRF type radar device that performs a synthetic band process for synthesizing a band by performing an inverse Fourier transform is disclosed. In such a radar device, since the band is synthesized by the combined band processing, it is possible to detect the relative distance to the target with high distance resolution without widening the band of the receiving circuit.

Japanese Unexamined Patent Publication No. 2001-272463

However, in the technique described in Patent Document 1, it is difficult to perform highly accurate distance measurement when frequency conversion is performed using such distance information when the error of the distance information from the platform is large.

The present disclosure has been made in view of the above, and an object of the present disclosure is to obtain a radar device capable of performing highly accurate distance measurement without using distance information from a platform.

In order to solve the above-mentioned problems and achieve the object, the radar device of the present disclosure includes a transmission pulse generation unit, an antenna device, a first frequency conversion unit, a plurality of second frequency conversion units, and a plurality of synthesis units. It includes a band processing unit and a detection processing unit. The transmission pulse generator uses a plurality of frequency conversion signals whose frequencies are deviated by a predetermined step frequency in a predetermined pulse repetition cycle, and a plurality of transmission pulses whose frequencies are deviated by a step frequency in a pulse repetition cycle. Generate a signal. The antenna device converts a plurality of transmitted pulse signals into a plurality of pulse waves and radiates them, receives the plurality of pulse waves reflected by the target, and outputs the plurality of received pulse signals. The first frequency conversion unit performs frequency conversion of a plurality of received pulse signals based on the plurality of frequency conversion signals and the local signal. The plurality of second frequency conversion units shift the frequencies of the plurality of received pulse signals whose frequency has been converted by the first frequency conversion unit at frequencies that are integral multiples of the step frequency and are different from each other. Each of the plurality of synthetic band processing units performs synthetic band processing of a plurality of received pulse signals whose frequencies are shifted by the corresponding second frequency conversion unit among the plurality of second frequency conversion units. The detection processing unit detects the relative distance to the target based on the result of the synthetic band processing by the plurality of synthetic band processing units.

According to the present disclosure, there is an effect that highly accurate distance measurement can be performed without using distance information from the platform.

The figure which shows an example of the structure of the radar apparatus which concerns on Embodiment 1. The figure which shows an example of the structure of the transmission pulse generation part which concerns on Embodiment 1. The figure which shows an example of the plurality of transmission pulse signals output from the transmission pulse generation part which concerns on Embodiment 1. The figure which shows an example of the relationship between a plurality of transmission pulse signals and a plurality of reception pulse signals which concerns on Embodiment 1. The figure which shows an example of the structure of the 1st frequency conversion part which concerns on Embodiment 1. The figure which shows an example of the structure of the plurality of 2nd frequency conversion part which concerns on Embodiment 1. The figure for demonstrating the signal processing in the radar apparatus which concerns on Embodiment 1.

Hereinafter, the radar device according to the embodiment will be described in detail with reference to the drawings.

Embodiment 1.
FIG. 1 is a diagram showing an example of the configuration of the radar device according to the first embodiment. The radar device 100 shown in FIG. 1 is an HPRF type radar device, and performs distance measurement without using distance information from the platform. The radar device 100 is mounted on a moving platform such as a flying object, emits a pulsed radio wave into space, receives a pulsed radio wave reflected by the target, and detects a relative distance to the target.

As shown in FIG. 1, the radar device 100 includes a transmission pulse generation unit 1, a circulator 2, an antenna device 3, a first frequency conversion unit 4, an analog-digital conversion unit 5, and a plurality of second frequency conversion units. It _{is provided with 60, 6 1, 62, ..., 6 n, a plurality of synthetic band processing units 70, 7 1, 7 2, ..., 7 n , and a detection processing unit 8} . n is, for example, an integer of 4 or more. In the following, when each of a plurality of _second frequency conversion units 60, 6 ₁ , ₆₂ , ..., 6 _n is shown without distinction, it may be referred to as a second frequency conversion unit 6. When each of the plurality of synthetic band processing units 70, 7 ₁ , _{7 2 ,} ..., 7 _n is shown without distinction, it may be described as the synthetic band processing unit 7.

FIG. 2 is a diagram showing an example of the configuration of the transmission pulse generation unit according to the first embodiment. As shown in FIG. 2, the transmission pulse generation unit 1 has a plurality of frequency conversion signals _{Sr1 0} , Sr1 ₁ , Sr1 ₂ , ... , Sr1 _n are used to sequentially generate a plurality of transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , ..., Ssp _n whose frequencies are shifted by the step frequency Δf in the pulse repetition period T _pri .

The frequency of the frequency conversion signal Sr10 is " ₀ ", the frequency of the frequency conversion signal Sr1 ₁ is "Δf", the frequency of the frequency conversion signal Sr1 ₂ is "2Δf", and the frequency conversion signal Sr1 The frequency of ₃ is "3Δf", and the frequency of the frequency conversion signal _Sr1n is "nΔf".

The frequency of the transmission pulse signal Ssp ₀ is "f1", the frequency of the transmission pulse signal Ssp ₁ is "f1 + Δf", the frequency of the transmission pulse signal Ssp ₂ is "f1 + 2Δf", and the frequency of the transmission pulse signal Ssp ₃ is. It is "f1 + 3Δf", and the frequency of the transmission pulse signal _Sspn is "f1 + nΔf".

Note that "2Δf" is a frequency twice the step frequency Δf, "3Δf" is a frequency three times the step frequency Δf, and "nΔf" is a frequency n times the step frequency Δf. In the following, when each of a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ , Sr1 ₂ , ..., Sr1 _n is shown without distinction, it may be described as a frequency conversion signal Sr1. Further, in the following, when each of a plurality of transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , ..., Ssp _n is shown without distinction, it may be described as a transmission pulse signal Ssp.

FIG. 3 is a diagram showing an example of a plurality of transmission pulse signals output from the transmission pulse generation unit according to the first embodiment. FIG. 3 shows an example in which a plurality of transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , Ssp ₃ , and Ssp ₄ are sequentially transmitted in a pulse repetition period T _pri when n = 4.

In the example shown in FIG. 3, the time t0, t1, t2, t3, t4, t5 is the output start timing of the transmission pulse signal Ssp, and the transmission pulse generation unit 1 is the transmission pulse from the output start timing to a certain time later. The transmission pulse signal Ssp is output as the output timing of the signal Ssp. In the example shown in FIG. 3, the maximum detection distance of the radar device 100 is a distance corresponding to a period of 5 times the pulse repetition period T _pri . The “transmission frequency” shown in FIG. 3 represents a change in the frequency of the transmission pulse signal Ssp.

Returning to FIG. 2, the description of the transmission pulse generation unit 1 will be continued. As shown in FIG. 2, the transmission pulse generation unit 1 includes a transmission signal generation unit 10, a frequency synthesizer 11, a mixer 12, and a power amplification unit 13. The transmission signal generation unit 10 generates a transmission signal Ss having a frequency f1 and outputs the transmission signal Ss to the mixer 12. The frequency synthesizer 11 sequentially outputs a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ , Sr1 ₂ , ..., Sr1 _n to the mixer 12 at the output timing generated in the pulse repetition cycle T _pri .

The mixer 12 mixes the transmission signal Ss output from the transmission signal generation unit 10 with a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ , Sr1 ₂ , ..., Sr1 _n output from the frequency synthesizer 11. Then, the pulse signals converted to different frequencies are sequentially generated as the transmission pulse signal Ssp for each output timing described above, and the generated transmission pulse signal Ssp is sequentially output to the power amplification unit 13.

The frequency of the transmission pulse signal Ssp output from the mixer 12 is switched in the order of f1, f1 + Δf, f1 + 2Δf, ..., F1 + nΔf for each output timing. The power amplification unit 13 amplifies the power of a plurality of transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , ..., Ssp _n sequentially output from the mixer 12. The plurality of transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , ..., Ssp _n power-amplified by the power amplification unit 13 are a plurality of pulse waves which are pulse-shaped radio waves from the antenna device 3 via the circulator 2. It is converted to and radiated into space.

The plurality of pulse waves radiated from the antenna device 3 into space are sequentially received by the antenna device 3 as a plurality of RF (Radio Frequency) signals to which the Doppler frequency fd is added after being reflected by the target. The plurality of RF signals sequentially received by the antenna device 3 are the plurality of received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n from the antenna device 3 via the circulator 2 and the first frequency converter 4 It is output sequentially to.

FIG. 4 is a diagram showing an example of the relationship between the plurality of transmission pulse signals and the plurality of reception pulse signals according to the first embodiment. FIG. 4 shows an example in which the received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , Srp ₃ , and Srp ₄ are sequentially received in the pulse repetition period T _pri when n = 4 in the radar device 100. Hereinafter, when each of the received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , Srp ₃ , and Srp ₄ is shown without distinction, it may be referred to as a received pulse signal Srp.

In the example shown in FIG. 4, the received pulse signal Srp ₀ is received between the time t1 and the time t2, and the received pulse signal Srp ₁ is received between the time t2 and the time t3. The received pulse signal Srp ₂ is received between time t3 and time t4, and the received pulse signal Srp ₃ is received between time t4 and time t5. The received pulse signal Srp ₄ is received between the time t5 and the time t6.

Next, the first frequency conversion unit 4 shown in FIG. 1 will be described. FIG. 5 is a diagram showing an example of the configuration of the first frequency conversion unit according to the first embodiment. As shown in FIG. 5, the first frequency conversion unit 4 has a plurality of received pulse signals based on a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ , Sr1 ₂ , ..., Sr1 _n and a local signal Lo 1. The frequencies of Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n are changed.

The first frequency conversion unit 4 includes a local oscillator 40, mixers 41 and 42, and a low-pass filter 43. The local oscillator 40 outputs a local signal Lo 1 for down-converting a plurality of received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n to a frequency band of the IF (Intermediate Frequency) band to the mixer 41. ..

The mixer 41 is a plurality of intermediate signals Si ₀ , Si ₁ , which are signals obtained by down-converting a plurality of received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n output from the circulator 2 to the IF band. Si ₂ , ..., _Sign is generated. Specifically, the mixer 41 mixes a plurality of received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n with a local signal Lo 1 output from the local oscillator 40, thereby forming a plurality of intermediate signals. Si ₀ , Si ₁ , Si ₂ , ..., _Sign is generated.

The plurality of intermediate signals Si ₀ , Si ₁ , _{Si 2} , ..., Sign generated by the mixer 41 are output from the mixer 41 to the mixer 42. The mixer 42 is a plurality of intermediate signals Si ₀ , Si ₁ , Si ₂ , ..., Si _n sequentially output from the frequency synthesizer 11 and a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ sequentially output from the mixer 41. , Sr1 ₂ , ..., Sr1 _n are mixed to perform frequency conversion of the signal output from the mixer 42.

Here, it is assumed that n = 4 and the transmission pulse signal Ssp and the reception pulse signal Srp have the relationship shown in FIG. In this case, the frequency conversion signal Sr10 is output between the time _t0 and the time t1 and between the time t5 and the time t6, and the frequency conversion signal Sr1 ₁ is output between the time t1 and the time t2. The frequency conversion signal Sr1 ₂ is output between the time t2 and the time t3. Further, the frequency conversion signal Sr1 ₃ is output between the time t3 and the time t4, and the frequency conversion signal Sr1 ₄ is output between the time t4 and the time t5.

Further, the intermediate signal Si ₀ is output between the time t1 and the time t2, the intermediate signal Si ₁ is output between the time t2 and the time t3, and the intermediate signal Si ₂ is output between the time t3 and the time t4. Is output between. The intermediate signal Si ₃ is output between the time t4 and the time t5, and the intermediate signal Si ₄ is output between the time t5 and the time t6. Therefore, the frequency conversion signal Sr1 ₁ is mixed with the intermediate signal Si ₀ , the frequency conversion signal Sr1 ₂ is mixed with the intermediate signal Si ₁ , and the frequency conversion signal Sr1 ₃ is mixed with the intermediate signal Si ₂ . Further, the frequency conversion signal Sr1 ₄ is mixed with the intermediate signal Si ₃ , and the frequency conversion signal _Sr10 is mixed with the intermediate signal Si ₄ .

The low-pass filter 43 removes signals in an unnecessary band from a plurality of intermediate signals _{Si 0} , Si ₁ , Si ₂ , ..., Sign whose frequency has been converted by the mixer 42. In the following, a plurality of intermediate signals Si ₀ , Si ₁ , Si ₂ , ..., S in of which unnecessary band signals have been removed by the low-pass filter 43 are converted into a plurality of signals _{Sh 0} , Sh ₁ , Sh ₂ , ...・, It may be described as Sh _n .

The analog-to-digital conversion unit 5 converts the signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n output from the low-pass filter 43 from the analog signal to the digital signal. A plurality of signals converted into digital signals by the analog-to-digital conversion unit 5 Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n are a plurality of _second frequency conversion units 60, 6 ₁ , ₆₂ , ...・, It is distributed to 6 _n .

FIG. 6 is a diagram showing an example of the configuration of a plurality of second frequency conversion units according to the first embodiment. The plurality of _second frequency conversion units 60, 6 ₁ , ₆₂ , ..., 6 _n shown in FIG. 6 are a plurality of signals Sh ₀ , Sh ₁ , Sh converted into digital signals by the analog digital conversion unit 5. _2. A frequency shift is performed in which the frequency of Sh _n is decremented by a frequency that is an integral multiple of the step frequency Δf and is different from each other.

Specifically, the second frequency conversion unit ₆₀ includes a local oscillator 500, a mixer ₅₁₀ , and a _bandpass filter ₅₂₀ . The local oscillator 500 outputs the frequency conversion signal Sr2 ₀ having a frequency of “ ₀ ”. The mixer 51 ₀ is a plurality of signals whose frequency is shifted at the frequency of “0” by mixing the frequency conversion signal Sr2 ₀ with the plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n . A plurality of signals Sh 0 0, Sh 0 ₁ , Sh 0 ₂ , ..., Sh _{0 n} , which are Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n , are output. The bandpass filter ₅₂₀ passes a specific frequency among the output signals of the mixer ₅₁₀ and attenuates a frequency other than the specific frequency. The radar device 100 may be configured such that the digital signal output from the analog-digital conversion unit ₅ is directly input to the _synthesis band processing unit 70 without providing the second frequency conversion unit 60.

The second frequency conversion unit 61 includes a local oscillator ₅₀₁ , a mixer 51 ₁ , and _{a bandpass filter 52 1 .} The local oscillator 501 outputs _{a frequency conversion signal Sr2 1 having} a frequency of “Δf”. The mixer 51 ₁ mixes the frequency conversion signal Sr2 ₁ with the plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n , and thereby the plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ... A plurality of signals in which each frequency of Sh _n is frequency-shifted by “−Δf” Sh ₀ , Sh ₁ , Sh ₂ , ..., Multiple signals that are Sh _n Sh1 ₀ , Sh1 ₁ , Sh1 ₂ , ..., Sh1 _n is output. The bandpass filter 52 ₁ passes a specific frequency in the output signal of the mixer 51 ₁ and attenuates a frequency other than the specific frequency.

The second frequency conversion unit 6 ₂ includes a local oscillator 50 ₂ , a mixer 51 ₂ , and a bandpass filter 52 ₂ . The local oscillator _{502 outputs a frequency conversion signal Sr2 2 having} a frequency of “2Δf”. The mixer 51 ₂ mixes the frequency conversion signal Sr2 _n with the signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n , and thereby a plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Signals in which each frequency of Sh _n is frequency-shifted by "-2Δf" Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n signals Sh2 ₀ , Sh2 ₁ , Sh2 ₂ , ..., Sh2 Output _n . The bandpass filter 52 ₂ passes a specific frequency in the output signal of the mixer ₅₁₂ and attenuates a frequency other than the specific frequency.

The second frequency conversion unit 6 _n includes a local oscillator 50 _n , a mixer 51 _n , and a bandpass filter 52 _n . The local oscillator 50 _n outputs a frequency conversion signal Sr2 _n having a frequency of “nΔf”. The mixer 51 _n mixes the frequency conversion signal Sr2 ₃ with the signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n , and thereby a plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Signals in which each frequency of Sh _n is frequency-shifted by "-nΔf" Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n signals Shn ₀ , Shn ₁ , Shn ₂ , ..., Shn Output _n . The bandpass filter 52 _n passes a specific frequency in the output signal of the mixer 51 _n and attenuates a frequency other than the specific frequency.

As described above, in the second frequency conversion unit 60 to _{6 n} , the output signals of the mixers 51 ₀ to 51 _n are passed through a specific frequency and attenuated by the BPF 52 ₀ to 52 _n . .. Of these second frequency converters ₆₀ to 6 _n , the output signal of the mixer of a specific second frequency converter corresponding to the delay of the received pulse signal Srp passes through the bandpass filter, and the other second frequency converters. The output signal of the mixer is attenuated by the bandpass filter.

The plurality of synthetic band processing units 70, 7 ₁ , 7 ₂ , ..., 7 _n shown in FIG. ₁ are of a plurality of _second frequency conversion units 60, 6 ₁ , ₆₂ , ..., 6 _n . Among them, the corresponding second frequency conversion unit executes the combined band processing for performing the combined band processing of a plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n whose frequencies are shifted. The composite band processing of a plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n performs an inverse Fourier transform on a plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n . This is the process of synthesizing the band.

Specifically, the synthetic band processing unit 70 performs inverse Fourier transform on _{a plurality of signals Sh0 0, Sh0 1 , Sh0 2} , ..., _{Sh0 n} output from the second frequency conversion unit 60. By doing so, the bandwidth will be widened. The combined band processing unit 7 ₁ widens the bandwidth by performing an inverse Fourier transform on a plurality of signals Sh1 ₀ , Sh1 ₁ , Sh1 ₂ , ..., Sh1 _n output from the _second frequency conversion unit 61. do.

The combined band processing unit 7 ₂ widens the bandwidth by performing an inverse Fourier transform on a plurality of signals Sh2 ₀ , Sh2 ₁ , Sh2 ₂ , ..., Sh2 _n output from the _second frequency conversion unit 62. do. The combined band processing unit 7 _n widens the bandwidth by performing an inverse Fourier transform on a plurality of signals Shan ₀ , Shan ₁ , Shan ₂ , ..., Shan _n output from the second frequency conversion unit 6 _n . do.

The detection processing unit 8 is targeted only in a circuit including a specific synthesis band processing unit corresponding to the delay of the received pulse signal Srp among _{a plurality of synthesis band processing units 70, 7 1 , 72, ..., 7 n .} Is detected, so the relative distance to the target can be detected. Therefore, the radar device 100 can perform high-precision distance measurement in the combined band processing without requiring frequency conversion by a frequency synthesizer based on the delay of the received pulse signal Srp.

The specific synthetic band processing unit described above is a synthetic band processing unit that synthesizes a plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n bands converted by a frequency conversion signal Sr1 of a specific frequency. Is. The specific frequency is the frequency corresponding to the delay time of the received pulse signal Srp with respect to the transmitted pulse signal Ssp.

The specific frequency described above is, for example, "Δf" when the reception time of the reception pulse signal Srp ₀ is between the transmission time of the transmission pulse signal Ssp ₀ and the transmission time of the transmission pulse signal Ssp ₁ . Further, the specific frequency is, for example, "2Δf" when the reception time of the reception pulse signal Srp ₀ is between the transmission time of the transmission pulse signal Ssp ₁ and the transmission time of the transmission pulse signal Ssp ₂ .

FIG. 7 is a diagram for explaining signal processing in the radar device according to the first embodiment. In FIG. 7, the relationship between the transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , Ssp ₃ , and Ssp ₄ and the reception pulse signals Srp ₀ , Srp ₁ , Srp ₂ , Srp ₃ , and Srp ₄ when n = 4 is shown. Shows. In the example shown in FIG. 7, the received pulse signal Srp ₀ having the frequency “f1” is the period in which the frequency of the transmitted pulse signal Ssp corresponds to “f1 + 2Δf”, that is, during the period from time t2 to time t3, in the antenna device 3. It has been received.

Therefore, the target should be detected only in the circuit including the second frequency conversion unit 6 ₂ and the synthetic band processing unit 7 ₂ corresponding to the “reception conversion frequency 3” shown in FIG. 7 obtained by subtracting “2Δf” from the transmission frequency. Can be done. In this case, the detection processing unit 8 can detect the relative distance to the target based on the result of the synthetic band processing by the synthetic band processing unit ₇₂ .

The “reception conversion frequency ₁ ” shown in FIG. 7 is the same as the frequency of the transmission pulse signal _Ssp , and corresponds to a circuit including a second frequency conversion unit 60 and a combined band processing unit 70. In the circuit including the second frequency conversion unit 60 and the synthetic band processing unit 70, the target is when the reception pulse signal _{Srp 0 having} the frequency f1 is received during the period corresponding to the frequency of the transmission pulse signal Ssp "f1". Can be detected.

Further, the “reception conversion frequency 2” shown in FIG. 7 is a frequency obtained by subtracting “Δf” from the frequency of the transmission pulse signal Ssp, and is a circuit including the _second frequency conversion unit ₆₁ and the combined band processing unit 71. Corresponds to. In the circuit including the _second frequency conversion unit 6 ₁ and the synthetic band processing unit 71, the target is when the reception pulse signal Srp ₀ having the frequency f1 is received during the period corresponding to the frequency of the transmission pulse signal Ssp "f1 + Δf". Can be detected.

Further, the “reception conversion frequency 4” shown in FIG. 7 is a frequency obtained by subtracting “3Δf” from the frequency of the transmission pulse signal Ssp, and is a circuit including the _second frequency conversion unit ₆₃ and the combined band processing unit 73. Corresponds to. In the circuit including the _second frequency conversion unit ₆₃ and the synthetic band processing unit 73, the target is when the reception pulse signal Srp ₀ having the frequency f1 is received during the period corresponding to the frequency of the transmission pulse signal Ssp "f1 + 3Δf". Can be detected.

Further, the “reception conversion frequency 5” shown in FIG. 7 is a frequency obtained by subtracting “4Δf” from the frequency of the transmission pulse signal Ssp, and is a circuit including the _second frequency conversion unit 64 and the synthetic band processing unit ₇₄ . Corresponds to. _In the circuit including the _second frequency conversion unit 64 and the synthetic band processing unit 74, the target is when the reception pulse signal Srp ₀ having the frequency f1 is received during the period corresponding to the frequency of the transmission pulse signal Ssp "f1 + 4Δf". Can be detected.

In the HPRF radar device, when performing parallel processing using multiple frequency synthesizers that perform frequency conversion for the received pulsed analog signal at different timings in order to measure the distance without distance information from the platform, a circuit. The configuration becomes large and the size becomes large. Therefore, it is difficult to mount a radar device that performs parallel processing of analog signals using a plurality of frequency synthesizers in a limited volume such as a flyer. Further, when the analog signal is branched into a plurality of parts for parallel processing of the analog signal, the SN (Signal-to-Noise) ratio deteriorates and the detection distance performance deteriorates.

On the other hand, in the radar device 100 according to the first embodiment, the target can be detected by the synthetic band processing unit corresponding to a specific frequency regardless of the reception timing of the received pulse signal Srp, but the target corresponds to a specific frequency. The target cannot be detected by the synthetic band processing unit other than the synthetic band processing unit. Therefore, in the radar device 100, highly accurate distance measurement is possible by the combined band processing without requiring frequency conversion by a plurality of frequency synthesizers.

Further, in the radar device 100, since the digital signal is processed in parallel by a plurality of circuits including the second frequency conversion unit 6 and the combined band processing unit 7, deterioration of the SN ratio can be prevented and the detection distance is improved. Can be made to. Further, in the radar device 100, since the digital signal is processed in parallel by the plurality of circuits described above, these plurality of circuits can be miniaturized. Therefore, in the radar device 100, it is possible to reduce the size and weight of the entire radar device with respect to the load capacity of a platform such as a flying object.

As described above, the radar device 100 according to the first embodiment includes the transmission pulse generation unit 1, the antenna device 3, the first frequency conversion unit 4, and a plurality of second frequency conversion units 60, 6 ₁ , ₆ . It includes ₂ , ..., 6 _n , a plurality of combined band processing units 70, 7 ₁ , _{7 2 ,} ..., 7 _n , and a detection processing unit 8. The transmission pulse generation unit 1 has a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ , Sr1 ₂ , ..., Sr1 _n whose frequencies are deviated by a predetermined step frequency Δf with a predetermined pulse repetition period T _pri . Is used to generate a plurality of transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , ..., Ssp _n whose frequencies are shifted by the step frequency Δf in the pulse repetition period T _pri . The antenna device 3 converts a plurality of transmission pulse signals Ssp ₀ , Ssp ₁ , Ssp ₂ , ..., Ssp _n into a plurality of pulse waves and radiates them, and receives a plurality of pulse waves reflected by the target. Multiple received pulse signals are output as Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n . The first frequency conversion unit 4 has a plurality of received pulse signals Srp ₀ , Srp ₁ , Srp based on a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ , Sr1 ₂ , ..., Sr1 _n and a local signal Lo1. _2. Perform frequency conversion of Srp _n . The plurality of _second frequency conversion units 60, 6 ₁ , ₆₂ , ..., 6 _n are a plurality of received pulse signals Srp ₀ , Srp ₁ , Srp ₂ whose frequency has been converted by the first frequency conversion unit 4. _{,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, . _ _ _} The plurality of synthetic band processing units 70, 7 ₁ , 7 ₂ , ..., 7 _n correspond to the corresponding _third of the plurality of _second frequency conversion units 60, 6 ₁ , ₆₂ , ..., 6 _n . The combined band processing of a plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n whose frequencies are shifted by the frequency conversion unit is performed, respectively. The detection processing unit 8 detects the relative distance to the target based on the result of the combined band processing by the plurality of combined band processing units ₇₀ , ₇₁ , ₇₂ , ..., 7 _n . As a result, the radar device 100 can perform highly accurate distance measurement without using the distance information from the platform.

Further, the radar device 100 has a plurality of signals Sh ₀ , Sh ₁ , Sh which are received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n whose frequency has been converted by the first frequency conversion unit 4. _2. An analog-to-digital conversion unit 5 that converts Sh _n from an analog signal to a digital signal is provided. The plurality of second frequency conversion units 6 convert the plurality of signals Sh ₀ , Sh ₁ , Sh ₂ , ..., Sh _n converted into digital signals by the analog-to-digital conversion unit 5 into frequencies that are integral multiples of the step frequency Δf. And they shift at different frequencies. As a result, in the radar device 100, since the digital signals are processed in parallel by a plurality of circuits, deterioration of the SN ratio can be prevented and the detection distance can be improved. Further, in the radar device 100, since the digital signals are processed in parallel by a plurality of circuits, these plurality of circuits can be miniaturized. Therefore, in the radar device 100, it is possible to reduce the size and weight of the entire radar device with respect to the load capacity of a platform such as a flying object.

Further, the first frequency conversion unit 4 includes mixers 41 and 42. The mixer 41 is an example of the first mixer, and the mixer 42 is an example of the second mixer. The mixer 41 mixes a plurality of received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , ..., Srp _n and a local signal Lo 1, and a plurality of received pulse signals Srp ₀ , Srp ₁ , Srp ₂ , ... -Converts Srp _n to a signal in the intermediate frequency band. The mixer 42 has a plurality of received pulse signals whose frequencies are converted into intermediate frequency bands, Srp ₀ , Srp ₁ , Srp ₂ , ..., Intermediate signals Si ₀ , Si ₁ , Si ₂ , ..., Which are Srp _n . Mixing Si _n with a plurality of frequency conversion signals Sr1 ₀ , Sr1 ₁ , Sr1 ₂ , ..., Sr1 _n . As a result, the radar device 100 can perform high-precision distance measurement without performing parallel processing using a plurality of frequency synthesizers, and can suppress the increase in size of the radar device 100.

The configuration shown in the above embodiment is an example, and can be combined with another known technique, or a part of the configuration may be omitted or changed without departing from the gist. It is possible.

1 Transmission pulse generator, 2 Circulator, 3 Antenna device, 4 1st frequency converter, 5 Analog-to-digital converter, 6, 6 ₀ , 6 ₁ , 6 ₂ , ..., 6 _n 2nd frequency converter, 7 , 70, 7 ₁ , _{7 2 ,} ..., 7 _n Synthetic band processing unit, 8 Detection processing unit, 10 Transmission signal generation unit, 11 Frequency synthesizer, 12, 41, 42, 51 ₀ , 51 ₁ , 51 ₂ , ..., 51 _n mixer, 13 power amplification unit, 40, 50 ₀ , 50 ₁ , ₅₀₂ , ..., 50 _n local oscillator, 43 low _{-pass filter, 520, 52 1, 52 2 , ...} , 52 _n bandpass filter, 100 radar device.

Claims (3)

Using a plurality of frequency conversion signals whose frequencies are deviated by a predetermined step frequency in a predetermined pulse repetition cycle, a plurality of transmission pulse signals whose frequencies are deviated by the step frequency in the pulse repetition cycle are generated. Transmission pulse generator and
An antenna device that converts the plurality of transmission pulse signals into a plurality of pulse waves and radiates them, receives the plurality of pulse waves reflected by the target, and outputs the plurality of reception pulse signals.
A first frequency conversion unit that performs frequency conversion of the plurality of received pulse signals based on the plurality of frequency conversion signals and the local signal.
A plurality of second frequency conversion units that shift the frequencies of the plurality of received pulse signals whose frequency has been converted by the first frequency conversion unit at frequencies that are integral multiples of the step frequency and are different from each other.
A plurality of synthetic band processing units, each of which performs synthetic band processing of the plurality of received pulse signals whose frequency has been shifted by the corresponding second frequency conversion unit among the plurality of second frequency conversion units.
A radar device including a detection processing unit that detects a relative distance to the target based on the result of the combined band processing by the plurality of combined band processing units. It is provided with an analog-digital conversion unit that converts the plurality of received pulse signals whose frequency has been converted by the first frequency conversion unit from an analog signal to a digital signal.
The plurality of second frequency conversion units are
The first aspect of claim 1, wherein the frequencies of the plurality of received pulse signals converted into the digital signals by the analog-to-digital conversion unit are shifted by frequencies that are integral multiples of the step frequency and are different from each other. Radar device. The first frequency conversion unit is
A first mixer that mixes the plurality of received pulse signals and the local signal and converts the plurality of received pulse signals into signals in the intermediate frequency band.
The radar device according to claim 1 or 2, further comprising a second mixer that mixes the plurality of received pulse signals whose frequencies are converted into the intermediate frequency band and the plurality of frequency conversion signals. ..

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