JP3438409B2 - Radar equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device having a small peak transmission power and a small size and a light weight, for increasing the detection distance and improving the range resolution.

[0002]

2. Description of the Related Art FIG. 28 is a diagram showing a conventional pulse radar device, in which 1 is an antenna that radiates a transmitted wave in a space in a specific direction and receives a reflected wave, and 2 is a beam pointing direction of the antenna. A beam controller, 3 is an exciter for generating a transmission wave, 4 is a pulse compression modulator for performing linear frequency modulation for chirp pulse compression on the transmission wave at a constant frequency sweep rate, and 6 is the above A circulator that supplies a transmission signal to the antenna and a reception signal to the receiver, 7
Is a receiver that amplifies the received signal, and 8 is an A / D that converts the signal output from the receiver into a digital video signal
A converter, 9 is a timing generator for generating frequency modulation timing and A / D conversion sampling timing, 10
Is a pulse compressor for performing correlation processing for chirp pulse compression on the digital video signal output from the A / D converter, and 11 is a target for detecting a target distance from the data output from the pulse compressor. A detector, 12 is a display for displaying the target distance information output from the target detector, and 13 is a radar controller for setting the beam controller and the timing generator.

A configuration example of the pulse compressor 10 is shown in FIG. 30 is an F that performs a fast Fourier transform on the input signal
FT (Fast Fourier Transform)
m) arithmetic unit, 31 is a reference function storage memory for storing a reference function for chirp pulse compression, 32 is a complex multiplier for multiplying the output signal of the FFT arithmetic unit by the data input from the reference function storage memory, 33 Is a fast inverse Fourier transform of the data output from the complex multiplier I
FFT (Inverse Fast Fourier)
Transform) arithmetic unit. The input target signal is converted into a signal in the frequency domain in the FFT calculator 30, and is multiplied by the reference function in the complex multiplier 32 to restore the frequency modulation performed at the time of transmission. The pulse compression process can be performed by returning this signal to the time domain again by the IFFT calculator 33.

The conventional pulse radar apparatus is constructed as described above, and for example, the frequency modulation timing 14 having the pulse width T as shown in FIG. 30 is generated by the timing generator 9 and the transmission wave generated by the exciter 3 is generated. Then, the pulse compression modulator 4 applies a linear frequency modulation 34 having a modulation interval τs and a modulation width ΔF as shown in FIG.
Is used as the transmission pulse timing as it is and is radiated from the antenna 1. At this time, the frequency modulation width ΔF is determined by W / τ by the pulse width τ after compression and the spread coefficient W. The frequency sweep rate Δf is ΔF / T. The signal reflected and received by the target at the position of the distance R is amplified by the receiver 7, sampled at the sampling interval Δt by the A / D converter 8 and converted into the digital video signal 16. The frequency modulation band of the transmission signal is -ΔF / 2 to + ΔF
Since it is / 2, it is necessary to sample at a frequency of ΔF or more according to the sampling theorem in order to store the frequency information, so the sampling interval Δt ≦ τ / W must be satisfied. The pulse compressor 10 performs a pulse compression process using a correlation process on this signal. As a result, the pulse compression result 17 as shown in FIG. 30 can be obtained, and the signal of the long distance target can be detected by the target detector 12 without deteriorating the distance resolution.

FIG. 31 shows an example of a transmission pulse waveform that has been subjected to actual frequency modulation. The signal transmitted with this waveform is reflected by the target and converted into a digital video signal by the A / D converter 8 to obtain a waveform as shown in FIG. By subjecting this signal to the chirp pulse compression processing by the pulse compressor 10, the waveform shown in FIG. 33 is obtained. In the case of this example, the pulse width τ after compression is 2 × τs, and the sampling interval Δt in the A / D conversion is τ / W = 2 × τs /
It must be performed at W or less. Since the value of W is approximately 1 <W <2, the sampling interval Δt in the A / D conversion is τ
s. The amount of data in this example is 512.

Even when the pulse width after compression is 2 × τ, if the frequency sweep rate Δf and the frequency modulation width ΔF are the same, it is necessary to acquire data at the same A / D conversion sampling interval τs. Yes, the number of processed data does not change. Further, in order to change Δf, it is necessary to change the characteristics of the pulse compression modulator 4.

[0007]

In the conventional pulse radar device as described above, in order to maintain the modulation frequency band of the transmission wave shown in FIG. 31, sampling is performed at the modulation interval in the A / D converter. However, even if the distance resolution desired to be obtained with a low compression ratio is low, the number of processed data increases, and there is a problem that the processing time is too long. In order to reduce the number of processed data,
There is a problem that the modulation frequency characteristic of the pulse compression modulator has to be changed. Furthermore, since the same frequency modulation characteristic is always used, there is a high possibility that the frequency modulation characteristic is known to the target side.

The present invention has been made to solve such a problem, and when a pulse compression modulator having the same frequency modulation characteristic is used and a desired resolution at a low compression ratio is low, An object of the present invention is to obtain a radar device which can reduce the number of processed data and can process at high speed. Further, it is an object of the present invention to obtain a radar device in which it is difficult for the target side to know the frequency modulation characteristic by changing the frequency band to be used even with the same frequency modulation characteristic.

[0009]

A radar apparatus according to a first embodiment of the present invention extracts only a central portion of a modulated transmission wave by a time gate circuit, and further delays a sampling cycle in an A / D converter. By doing so, the amount of data is reduced.

The radar apparatus according to the second embodiment of the present invention is
For the modulated transmission wave, only the latter half of the transmission wave is extracted by the time gate circuit, and digital frequency modulation is performed on the data output from the A / D converter, enabling data thinning, Reduce the amount of data in the pulse compressor.

The radar apparatus according to the third embodiment of the present invention is
For the modulated transmission wave, only the first half of the transmission wave is extracted by the time gate circuit, and digital frequency modulation is performed on the data output from the A / D converter to enable data thinning, Reduce the amount of data in the pulse compressor.

A radar apparatus according to Embodiment 4 of the present invention is
By using all the modulated transmission waves and performing digital filtering on the data output from the A / D converter, data can be thinned and the amount of data in the pulse compressor is reduced.

A radar apparatus according to Embodiment 5 of the present invention is
By using all the modulated transmission waves and performing low-pass filtering on the data output from the receiver, the sampling cycle in the A / D converter is delayed,
Reduce the amount of data.

A radar apparatus according to Embodiment 6 of the present invention is
With respect to the modulated transmission wave, the center of the transmission wave, the first half or the latter half of the transmission wave is controlled by the radar controller by the time gate circuit, and at the same time, the sampling period in the A / D converter and the digital frequency modulator Insert
By controlling the modulation characteristics of the digital frequency modulator at the time of bypass and insertion from the radar controller, the amount of data is reduced and the frequency band used is changed.

[0015]

According to the first embodiment of the present invention, even in the pulse compression modulator having the same frequency modulation characteristic by using the time gate circuit, the data amount is reduced when the low compression ratio and the low distance resolution are sufficient. The pulse compression process can be performed at high speed to obtain a desired compression ratio and range resolution.

According to the second embodiment of the present invention, by using the time gate circuit and the digital frequency modulator, it is possible to perform high-speed pulse compression processing using the latter half of the transmitted wave.

According to the third embodiment of the present invention, by using the time gate circuit and the digital frequency modulator, it is possible to perform high-speed pulse compression processing using the first half of the transmitted wave.

According to the fourth embodiment of the present invention, the pulse compression process can be performed at high speed by using the digital filter arithmetic unit.

According to the fifth embodiment of the present invention, the pulse compression processing can be performed at high speed by using the low pass filter.

According to the sixth embodiment of the present invention, by changing the used frequency modulation band under the control of the radar controller, high-speed pulse compression processing is performed, and it is difficult for the target side to know the frequency modulation characteristic. can do.

[0021]

【Example】

Example 1. 1 is a diagram showing a first embodiment of the present invention,
1-4, 6-8 and 11-13 are exactly the same as the conventional device. Reference numeral 5 is a time gate circuit for extracting only a specific portion of the transmission wave modulated by the pulse compression modulator, and 9 is a conventional frequency modulation timing for the pulse compression modulator, and only the central portion thereof is extracted. A timing generator that sends a waveform as a transmission pulse timing to a time gate circuit, and also sends a sampling timing having a period twice that of a conventional A / D converter. It is a pulse compressor that performs correlation processing for.

In the radar device constructed as described above, in the pulse compression modulator 4, the same linear frequency modulation 34 as the conventional one is transmitted to the transmitted wave at the same frequency modulation timing 14 as the conventional one as shown in FIG. In the time gate circuit 5, the T / 2 width of the central portion is taken out by the transmission pulse timing 15 as shown in FIG. The signal reflected by the target and received by the A / D converter 8 has a period twice that of the conventional one.
Sampling is performed at × τs to obtain the reception signal 16 shown in FIG. The signal obtained here corresponds to the same distance range as the conventional one, but the data amount is halved.
By performing pulse compression processing on this signal with the pulse compressor 10, it is possible to obtain pulse compression result 17 shown in FIG.

FIG. 3 shows an example of a waveform obtained by actually performing frequency modulation.
Shown in. FIG. 4 shows a waveform obtained by extracting the central portion from this waveform at the transmission pulse timing. The signal transmitted in the waveform of FIG. 4 and reflected by the target is sampled by the A / D converter 8 at a sampling period twice that of the conventional one, and becomes the digital video signal shown in FIG. By subjecting this signal to pulse compression processing by the pulse compressor 10, the waveform shown in FIG. 6 is obtained. In the case of this example, the data amount is 256, which is 1/2 of the conventional amount.

In the case of this embodiment, the portion taken out at the transmission pulse timing from the frequency-modulated waveform has a T / 2 width, but if the width is T / n, the sampling period is n × τs.
The pulse width after compression is n × 1 / ΔF, but the data amount is 1 / n. If the deterioration of the compression ratio is allowed, the sampling period can be further delayed to reduce the data amount.

Example 2. FIG. 7 is a diagram showing a second embodiment of the present invention, in which 1-4, 6-8 and 11-13 are exactly the same as the conventional device. Reference numerals 5 and 10 are exactly the same as those in the first embodiment. 9 sends the conventional frequency modulation timing to the pulse compression modulator, sends the transmission pulse timing for extracting only the latter half portion to the time gate circuit, and the A / D converter has the conventional period sampling. Timing generator for sending intervals, 18 for A / D
It is a digital frequency modulator that performs digital frequency modulation on the digital video signal output from the converter and further performs data thinning processing to a required resolution.

The configuration of the digital frequency modulator 18 is shown in FIG.
Shown in. Reference numeral 19 is a frequency modulation coefficient memory that stores a coefficient for frequency-modulating an input signal by -ΔF / 4, 20 is a complex multiplier that multiplies the data of the frequency modulation memory by the input data, and 21 is the time of the data It is a thinning filter that takes out every other filter in the direction.

In the radar device configured as described above, the time gate circuit extracts the latter half of the frequency modulation timing 14 as shown in FIG. 9 at the transmission pulse timing 15 as shown in FIG. FIG. 10 shows a waveform obtained by extracting the latter half of the actual frequency-modulated waveform shown in FIG. The signal transmitted with the waveform of FIG. 10 and reflected by the target is sampled by the A / D converter 8 at the same sampling period as the conventional one, and becomes the digital video signal shown in FIG. When this signal is multiplied by the data in the frequency modulation coefficient memory 19 by the complex multiplier 20 in the digital frequency modulator, the waveform shown in FIG. 12 is obtained, and the decimation filter 21 extracts every other data to obtain the waveform shown in FIG.
The waveform is as shown in FIG. The signal obtained here corresponds to the same distance range as the conventional one, but the data amount is 1/2.
Has become. By subjecting this signal to pulse compression processing by the pulse compressor 10, the waveform shown in FIG. 14 is obtained.
In this example, the amount of data is 256, which is 1 /
It is 2.

In the case of this embodiment, the portion taken out at the transmission pulse timing from the frequency-modulated waveform has a T / 2 width, but if the width is T / n as in the first embodiment, the pulse width after compression is n. However, the data amount can be reduced to 1 / n by the thinning filter. Further, if the deterioration of the compression ratio is allowed, the data amount can be reduced by further thinning out.

Example 3. FIG. 15 is a diagram showing a third embodiment of the present invention, in which 1-4, 6-8 and 11-13 are exactly the same as the conventional device. Reference numerals 5 and 10 are exactly the same as those in the first embodiment. Reference numeral 9 sends the conventional frequency modulation timing to the pulse compression modulator, sends the transmission pulse timing for extracting only the first half portion thereof to the time gate circuit, and the A / D converter has the conventional sampling period. Timing generator for sending intervals, 18 is A /
The digital frequency modulator performs digital frequency modulation on the digital video signal output from the D converter with characteristics different from those of the second embodiment, and further performs data thinning processing to a required resolution.

The structure of the digital frequency modulator is the same as that shown in FIG. Reference numerals 20 and 21 are exactly the same as those of the apparatus of the second embodiment. A frequency modulation coefficient memory 19 stores a coefficient for frequency-modulating the input signal by + ΔF / 4.

In the radar device configured as described above, the transmission pulse timing 1 as shown in FIG. 16 is obtained by the time gate circuit for the transmission waveform 14 as shown in FIG.
Take out the first half by 5. FIG. 17 shows a waveform obtained by extracting the first half from the actual frequency-modulated waveform shown in FIG.
Shown in. The signal transmitted in the waveform of FIG. 17 and reflected by the target is sampled by the A / D converter 8 at the same sampling period as the conventional one, and becomes the digital video signal shown in FIG. When this signal is multiplied by the data of the frequency modulation coefficient memory 19 by the complex multiplier 20 in the digital frequency modulator, the waveform becomes the same as that in FIG.
When the data is taken out every other data at 1, the waveform becomes the same as that in FIG. The signal obtained here corresponds to the same distance range as the conventional one, but the data amount is halved. By subjecting this signal to pulse compression processing by the pulse compressor 10, the same waveform as in FIG. 14 is obtained. In the case of this example, the data amount is 256, which is half that of the conventional one.
Has become.

In the case of this embodiment, the portion taken out from the frequency-modulated waveform at the transmission pulse timing has a T / 2 width, but if the width is T / n as in the first embodiment, the pulse width after compression is n. However, the data amount can be reduced to 1 / n by the thinning filter. Further, if the deterioration of the compression ratio is allowed, the data amount can be reduced by further thinning out.

Example 4. FIG. 19 is a diagram showing a fourth embodiment of the present invention, in which 1-4, 6-9 and 11-13 are exactly the same as the conventional device. 10 is exactly the same as that of the first embodiment. 22 suppresses high frequency components in the digital video signal output from the A / D converter 8,
It is a digital filter arithmetic unit that performs low-pass filter processing that passes only low-frequency components, and further performs thinning processing to a required resolution.

FIG. 20 shows the configuration of the digital filter arithmetic unit.
Shown in. 21 is exactly the same as the device of the second embodiment. Reference numeral 23 is a low-pass digital filter that suppresses high-frequency components and passes only low-frequency components.

In the radar apparatus configured as described above, the signal transmitted with the waveform as shown in FIG. 3 and reflected by the target is sampled at the conventional cycle in the A / D converter, as shown in FIG. And get the same waveform as. When this signal is processed by the low-pass digital filter 23, the waveform shown in FIG.
The data shown in FIG. 22 is obtained by taking out every other data at. This is a signal corresponding to the same distance range as the conventional one, but the data amount is 1/2. By performing pulse compression processing on this signal by the pulse compressor 10, the waveform shown in FIG. 23 is obtained. In the case of this example, the data amount is 256, which is 1/2 of the conventional amount.

In the case of this embodiment, the frequency pass band of the low pass digital filter 23 is -ΔF / 4 to + ΔF / 4.
Is assumed, but the frequency pass band is -ΔF / 8 to + Δ
By setting to F / 8, the data amount can be further reduced to 1/2 by the thinning filter. Similarly, it is possible to reduce the data amount by changing the frequency pass band. Further, even in the frequency pass band in the case of this example, if the deterioration of the compression ratio is allowed, the data amount can be reduced by further thinning out.

Example 5. FIG. 24 is a diagram showing a fifth embodiment of the present invention, in which 1-4, 6-9 and 11-13 are exactly the same as the conventional device. 10 is exactly the same as that of the first embodiment. Reference numeral 24 is a low-pass filter that performs a low-pass filter process that suppresses high-frequency components and passes only low-frequency components with respect to the received signal output from the receiver.
Reference numeral 9 denotes a timing generator which sends a conventional modulation pulse to the pulse compression modulator and also sends a sampling interval having a period twice that of the conventional one to the A / D converter.

In the radar device configured as described above, the signal transmitted with the waveform as shown in FIG. 3 and reflected by the target is amplified in the receiver 7 and the high frequency component is converted by the low pass filter 24. Oppressed. The same waveform as in FIG. 22 can be obtained by sampling this signal in the A / D converter 8 at a cycle twice as long as that in the conventional case. This is a signal corresponding to the same distance range as the conventional one, but the data amount is 1/2. By subjecting this signal to pulse compression processing by the pulse compressor 10, the same waveform as in FIG. 23 is obtained. In the case of this example, the data amount is 256, which is 1/2 of the conventional amount.

Also in the case of this embodiment, the frequency pass band of the low-pass filter 24 is -ΔF / 4 to + as in the case of the fourth embodiment.
ΔF / 4 is assumed, but the frequency pass band is -ΔF /
By setting 8 to + ΔF / 8, the sampling cycle in the A / D converter 8 can be further doubled, and the data amount can be further reduced to 1/2. Similarly, it is possible to reduce the data amount by changing the frequency pass band. Also, if deterioration of the compression ratio is allowed even in the frequency pass band in the case of this example, it is possible to further delay the sampling period and reduce the data amount.

Example 6. FIG. 25 is a diagram showing a sixth embodiment of the present invention, in which 1-4, 6-9 and 11-12 are exactly the same as the conventional device. Reference numerals 5 and 10 are exactly the same as those in the first embodiment. Reference numeral 13 is a radar controller that changes the frequency modulation timing, the transmission pulse timing, and the A / D conversion sampling timing with respect to the timing generator 9 at the same time, and at the same time controls the digital frequency modulation controller, and 25 is the control of the radar controller. The insertion / bypass of the digital frequency modulator 18 is controlled by the
This is a digital frequency modulation controller capable of changing the contents of the frequency modulation coefficient memory 19.

The structure of the digital frequency modulation controller 25 is shown in FIG. Reference numerals 20 and 21 are exactly the same as those of the apparatus of the second embodiment. 19 is a frequency modulation coefficient memory whose contents can be changed by external control, 26 is a bypass path,
Whether to insert the digital frequency modulator 18 into the input data or to pass the bypass path 26 can be externally controlled.

In the radar apparatus constructed as described above, the timing generator 9 generates the frequency modulation timing 14 as shown in FIG.
27, the transmission pulse timing 27, 28, 29 is switched as shown in FIG. At the same time, when the transmission pulse timing of the A / D conversion sampling period is 27 under the control of the radar controller 13,
When the number is 28 times or 29 times that of the conventional case, it is generated from the timing generator 9 in the conventional cycle. For the received signal, at the transmission pulse timing 27, the radar controller 1
3 controls the digital frequency controller 25 to pass data through the bypass path 26. At the transmission pulse timing 28, the digital frequency modulator 18 is controlled to be inserted, and the content of the frequency modulation coefficient memory is set to -ΔF.
Data for / 4 modulation. Transmission pulse timing 28
In the case of, the digital frequency modulator 18 is controlled so as to be inserted, and the contents of the frequency modulation coefficient memory are used as data for + ΔF / 4 modulation. The signal output from the digital frequency modulation controller 25 corresponds to the same distance range as the conventional one, but the data amount is ½. By pulse-compressing this signal with the pulse compressor 10, the pulse compression result shown in the third embodiment is obtained when the transmission pulse timing is 27, the first embodiment is 28, the second embodiment is 29, and the second embodiment is 29.

[0043]

According to the first embodiment of the present invention, even in the pulse compression modulator having the same frequency modulation characteristic by using the time gate circuit, the data amount is reduced when the low compression ratio and the low distance resolution are sufficient. Therefore, the pulse compression processing can be performed at high speed.

According to the second embodiment of the present invention, by using the time gate circuit and the digital frequency modulator, it is possible to perform high-speed pulse compression processing using the latter half of the transmitted wave.

According to the third embodiment of the present invention, by using the time gate circuit and the digital frequency modulator, it is possible to perform high-speed pulse compression processing using the first half of the transmitted wave.

According to the fourth embodiment of the present invention, the pulse compression process can be performed at high speed by using the digital filter arithmetic unit.

According to the fifth embodiment of the present invention, the pulse compression processing can be performed at high speed by using the low pass filter.

According to the sixth embodiment of the present invention, by changing the used frequency modulation band under the control of the radar controller, the pulse compression processing is performed at high speed and the frequency modulation characteristic is hard to be known to the target side. be able to.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a radar device according to the present invention.

FIG. 2 is a diagram showing a transmission pulse waveform and a compression result of the first embodiment.

FIG. 3 is a diagram showing a frequency modulation waveform according to the first embodiment.

FIG. 4 is a diagram showing a transmission pulse waveform according to the first embodiment.

FIG. 5 is a diagram showing a received signal according to the first embodiment.

FIG. 6 is a diagram showing a pulse compression result of the first embodiment.

FIG. 7 is a diagram showing a second embodiment of the radar device according to the present invention.

FIG. 8 is a diagram showing a configuration of a digital frequency modulator according to a second embodiment.

FIG. 9 is a diagram showing a frequency modulation waveform and a transmission pulse waveform of the second embodiment.

FIG. 10 is a diagram showing a transmission pulse waveform according to the second embodiment.

FIG. 11 is a diagram showing a received waveform according to the second embodiment.

FIG. 12 is a diagram showing waveforms after digital frequency modulation according to the second embodiment.

FIG. 13 is a diagram showing waveforms after thinning according to the second embodiment.

FIG. 14 is a diagram showing a pulse compression result of the second embodiment.

FIG. 15 is a diagram showing a third embodiment of the radar device according to the present invention.

FIG. 16 is a diagram showing frequency modulation and a transmission pulse waveform according to the third embodiment.

FIG. 17 is a diagram showing a transmission pulse waveform according to the third embodiment.

FIG. 18 is a diagram showing received waveforms according to the third embodiment.

FIG. 19 is a diagram showing a fourth embodiment of the radar device according to the present invention.

FIG. 20 is a diagram showing a configuration of a digital filter arithmetic unit according to a fourth embodiment.

FIG. 21 is a diagram showing waveforms after digital filtering according to the fourth embodiment.

FIG. 22 is a diagram showing waveforms after thinning according to the fourth embodiment.

FIG. 23 is a diagram showing a pulse compression result of the fourth embodiment.

FIG. 24 is a diagram showing a fifth embodiment of the radar device according to the present invention.

FIG. 25 is a diagram showing a sixth embodiment of the radar device according to the present invention.

FIG. 26 is a diagram showing the configuration of a digital frequency modulation controller according to the sixth embodiment.

FIG. 27 is a diagram showing frequency modulation and a transmission pulse waveform according to the sixth embodiment.

FIG. 28 is a diagram showing a conventional radar device.

FIG. 29 is a diagram showing a configuration of a conventional pulse compressor.

FIG. 30 is a diagram showing a conventional frequency modulation waveform and a pulse compression result.

FIG. 31 is a diagram showing a conventional frequency modulation waveform.

FIG. 32 is a diagram showing a conventional received signal.

FIG. 33 is a diagram showing a conventional pulse compression result.

[Explanation of symbols]

1 antenna, 2 beam controller, 3 exciter, 4 pulse compression modulator, 5 hour gate circuit, 6 circulator, 7 receiver, 8 A / D converter, 9 timing generator, 10 pulse compressor, 11 target Detector, 12
Indicator, 13 radar controller, 14 frequency modulation timing, 15 transmission pulse timing, 16 reception signal,
17 pulse compression result, 18 digital frequency modulator, 19 frequency modulation coefficient memory, 20 complex multiplier,
21 decimation filter, 22 digital filter calculator, 23 low pass digital filter, 24 low pass filter, 25 digital frequency modulation controller, 26
Bypass path, 27th Example 1 transmission pulse timing,
28 Example 2 transmission pulse timing, 29 Example 3 transmission pulse timing, 30 FFT calculator, 31 reference function storage memory, 32 complex multiplier, 33 IFFT calculator, 34 linear frequency modulation.

Claims (6)

(57) [Claims] 1. An antenna that radiates a transmitted wave in a space of a specific direction and receives a reflected wave, a beam controller that controls a beam pointing direction of the antenna, an exciter that generates the transmitted wave, and a transmitted wave. always use a pulse compression modulator for performing at a fixed frequency sweep rate, the transmission wave of the modulated pulse width T in the pulse compression modulator, the transmit pulse linear frequency modulation for chirped pulse compression for a time gate circuit for taking out the 1/2 of the central portion of supplies a transmission signal from the transmitting unit to the antenna, a circulator provides a received signal to a receiver, transmission pulse timing for the time gate circuit, the pulse A timing generator that generates sampling timing and the like for frequency modulation timing and the like for the compression modulator, and a receiver that amplifies the received signal, Letting τ be the sampling period when the pulse width is T, the signal output from the receiver is a digital video signal.
In the sampling period of 2 × tau converted A / D A / D (A
analog / digital) converter, a pulse compressor for performing correlation processing for chirp pulse compression with a data amount of 1/2 on the digital video signal output from the A / D converter, and the pulse compressor. A target detector that detects the target distance from the data output from the device, a display that displays the target distance information that is output from the target detector, and a radar control that sets the beam controller and the timing generator. A radar device comprising a container. 2. The second half of the transmission wave modulated by the pulse compression modulator by the time gate circuit is used as the transmission wave from the transmission wave modulated by the pulse compression modulator, and is output from the A / D converter. 2. The radar device according to claim 1, further comprising a digital frequency modulator that performs digital frequency modulation on the digital video signal and further performs thinning processing to a required resolution. 3. The first half of the transmission wave modulated by the pulse compression modulator by the time gate circuit is used as the transmission wave from the transmission wave modulated by the pulse compression modulator, and is output from the A / D converter. 2. The radar device according to claim 1, further comprising a digital frequency modulator that performs digital frequency modulation on the digital video signal and further performs thinning processing to a required resolution. 4. The transmission wave modulated by the pulse compression modulator is used as the transmission wave without using the time gate circuit, and is output from the A / D converter. The digital video signal is subjected to a low-pass filter process that suppresses high-frequency components and passes only low-frequency components, and a digital filter arithmetic unit that performs a thinning process to a required resolution is provided. The radar device according to claim 1. 5. A reception output from the receiver, which uses the entire transmission wave modulated from the transmission wave modulated by the pulse compression modulator without using the time gate circuit, as a transmission wave. The radar apparatus according to claim 1, further comprising a low-pass filter that suppresses high-frequency components of the signal and passes only low-frequency components. 6. The transmission pulse timing, the frequency modulation timing, and the A / D conversion sampling timing are changed with respect to the timing generator, and at the same time, the digital frequency modulator is inserted / bypassed and the modulation characteristic of the digital frequency modulator at the time of insertion is changed. The radar device according to claim 1, further comprising a radar controller that controls the radar.