JPH05312938A - Variable-period correlation type searching apparatus and variable-period correlation type signal detecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a searched signal or a detected signal having the excellent S/N in a searching apparatus, a signal detecting apparatus and the like for detecting the signals includ ing the required prearranged waveforms. CONSTITUTION:In the case of underground surveying apparatus, an extending type variable period signal 1XA, whose initial period T is made to extend by a small amount of time DELTAt every time, is delayed by a fixed amount (e.g. initial period T) and fixed. For every delayed fixed delay signal 1XA, a transmitting electromagnetic wave 4, wherein the prearranged waveform is a transmitting signal 2XA, is transmitted. The received signals of reflected electromagnetic waves 8 from underground buried materials 7A, 7B and 7C are made to be the correlated signals 10XA. The prearranged waveform for every variable-period signal 1XA is made to be a correlation signal 13XA. A multiplication signal 11XA, which is obtained by multiplying the correlated signal 10XA and the correlation signal 13XA, is integrated. An integrated signal 14XA is sampled and held, and searched signal 15XA is obtained. In the searched signal 15XA, the time is made to extend by T/DELTAt times, and correlation processing and pulse compression are performed at the same time. Thus, the searched signal having the excellent S/N is obtained. A variable period TE is made to be the shortened type, and the fixed delay is deformed so as to move to the side of the correlation signal 13XA. Thus, the same searched signal is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a required signal from received signals by a correlation detection type detection device which obtains a required detection signal by performing correlation using a promised waveform at the time of transmission, and a similar configuration. The present invention relates to a correlation type signal detection device.

[0002]

2. Description of the Related Art This type of detection device includes a reflection type detection device and a transmission type detection device. As a reflection type detection device, land conditions, ship navigation conditions, relative distance conditions, etc. are reflected by electromagnetic waves. For example, a radar for a ship that detects a situation such as a radar for a ship or a radar for an underground survey that detects a situation of buried objects under the surface of the earth, a situation of formation change, a situation of a relative distance, etc. There are fish detectors and sonars that detect distance conditions, etc., and transmission-type detection devices use the transmitted waves of electromagnetic waves (also called passing waves) to detect the status of buried objects and strata changes in underground paths between required points. There is a transmission / reception counter-detection sonar that detects the status of underwater objects / airborne objects using transmitted waves of sound waves and ultrasonic waves, such as transmission / reception opposed detection radar and borehole radar.

Further, in this type of detecting apparatus, as an apparatus provided with a correlation function to increase the detecting ability, that is, a correlation detecting type detecting apparatus, a plurality of received signals obtained in each detecting cycle are superposed. A structure having a correlation is used.

This configuration is based on the signals R1, R2 and R3 shown in FIG.
As described above, the signal CR1 is obtained by taking a correlation such that a plurality of reception signals of each detection period T obtained by transmitting the single pulse transmission signal X1 are superposed and logically summed or averaged. In addition, the reception signals S1 and S2 commonly existing at the same phase point of each detection cycle T are detected as detection signals.

In addition to the above, as a means for providing the correlation function, for example, a communication signal transmitted from a communication device or a monitoring device, or an information signal in which a monitoring signal in a facility is multiplexed is repeated at a predetermined cycle. Correlation-type signal detection apparatus configured to obtain a required detection signal by correlating with a correlation signal having a promised waveform for each time of its cycle, which is a signal including a waveform signal Can be considered.

[0006] In order to make such correlation effective, as a transmission waveform, a stepped amplitude format, a uniform waveform repeating format, etc. with specific promises for amplitude variation, frequency variation, phase variation, number of pulses, pulse interval, etc. In the former, the stepwise amplitude type is the one in which the amplitude is changed in a stepwise manner, and in the latter, the equal waveform repeating type is a sinusoidal half-wave pulse or rectangular pulse. Or a predetermined number of lines arranged in both positive and negative directions, and the simplest waveform is a single 1 as shown in FIG.
Cycle (in the present invention, called a monocycle),
There is a unipolar pulse corresponding to a single 1/2 cycle as shown in FIG.

The reason for providing the correlation function in the detection device is mainly to remove interference and environmental noise from a weak received signal with bad S / N so as to obtain a detected signal with good S / N, and Even if the power peak value is small, the detection distance can be increased. Similarly, even if the power peak value of the transmission signal is small, the pulse compression technology has a function to increase the detection distance. Yes, the configuration of pulse compression using waveforms such as staircase frequency modulation format, linear frequency modulation format, code phase modulation format, code carrier modulation format, etc. was published in June 1979 by the Institute of Electronics and Communication Engineers "Electronic Communication Series-Radar. Technology (No. 2) "and the like.

Here, the stepwise frequency modulation type is as follows:
As shown in the waveform (a) of FIG. 7, the frequency is changed as f1, f2, f3, f4, and f5 for each small unit time Ta, and the linear frequency modulation type is shown in FIG.
As in the waveform (a), the frequency is temporally changed.

Further, in the code phase modulation type, as shown in the waveform (c) of FIG. 7, each one cycle signal having a constant period Tb is used as one unit of pulse signal, and each one unit of pulse signal is The phase starts from 0 ° position is set to “+”, and the one starting from 180 ° position is set to “−” for encoding. Further, the code carrier modulation format is the waveform (a) in FIG. By changing the frequencies f1 to f5 of the signal in the stepwise frequency modulation type according to the above into carrier signals of the same frequency, the carrier wave in each unit time Ta is 1 in the code phase modulation type of the waveform (c) of FIG.
Each unit pulse is encoded in the same manner as the unit pulse.

It goes without saying that the waveforms in each of these forms can be used as the promised waveform for the above correlation function. In the present invention, the promised waveform is
It refers to the waveform in each of these formats.

[0011]

In the correlation structure in which a plurality of cycles are overlapped and a logical sum or an average is taken as shown in FIG. 8 as described above, even if the transmission waveform is a complicated promise waveform, the period T However, if the signals exist at the same location, that is, at the same phase point, they will be detected regardless of whether they are noise signals or interference signals.

Therefore, there is a problem in that it is desired to provide a simple and inexpensive structure that does not have such inconvenience.

[0013]

According to the present invention, a received signal of a reflected wave or a transmitted wave obtained by transmitting a transmission signal of a promise waveform that repeats at a predetermined cycle as described above is required to be correlated with the promise waveform. In the correlation detection type detecting device for obtaining the detection signal of, the variable cycle means for obtaining a variable cycle by sequentially extending the above cycle by a small amount of time each time, and at each time when a predetermined fixed delay amount is added to each variable cycle. Fixed delay transmission means for performing the above-mentioned transmission, variable period correlation signal means for obtaining the signal of the above-mentioned promise waveform as a correlation signal for each variable period, and multiplication of the received signal with the above correlation signal as the correlated signal. And a variable cycle means for obtaining a variable cycle in which the above cycle is sequentially shortened by a small amount of time each time. Variable period transmitting means for performing the above-mentioned transmission in the variable period, and fixed delay correlation signal means for obtaining the signal of the promise waveform as a correlation signal at each time when a predetermined fixed delay amount is added to each variable period, The above problem is solved by a configuration provided with a multiplication means for obtaining a detection signal based on a multiplication signal obtained by multiplying the received signal as a correlated signal by the correlation signal, and is also repeated at a required cycle. In a correlation type signal detection device for correlating a received signal including a signal of a promised waveform with a promised waveform to obtain a required detection signal, the above-mentioned problems can be solved by providing a similar configuration. is there.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described below with reference to FIG. The embodiment shown in FIG. 1 is an underground exploration radar for exploring the underground from the air, as shown in FIG.
The configuration is such that a cycle waveform, that is, a monocycle waveform is used as a simplest promise waveform for correlation, and signals of respective parts are shown in FIG.

In the variable period circuit 1X, the variable period signal 1XA, which is a pulse signal having a variable period TE that is sequentially extended by a small amount of time Δt each time in the first period, that is, the initial period T, is used as the fixed delay circuit 12. And the correlation signal circuit 13.

The variable period circuit 1X is, for example, a pulse generation circuit combining a Δt clock circuit and a counting circuit. When T = Δt × n is set, n is a fixed amount,
n + 1, n + 2, n + 3 ... n + r, n + (r + 1),
n + (r + 2) ... n + (n-2), n + (n-1),
By counting up to n + n and obtaining each cycle, T ~
A pulse signal having a variable period that is sequentially extended by a small amount of time Δt within a period of (T + Δt × n) is generated, and Δt is a transmission waveform circuit 21 and a correlation signal circuit 13 described later. Promised waveform generated in and, that is, transmission signal 2X
The time length TPX between A and the correlation signal 13XA is selected to be 1 / m, for example, 1/10.

The correlation signal circuit 13X is a variable period signal 1X.
This is a circuit for generating a promised waveform signal of a monocycle waveform having a time length TPX for each A as a correlation signal 13XA, and the generated correlation signal 13XA is given to one multiplication input of the multiplication circuit 11.

The fixed delay path 12 is a circuit for delaying the variable period signal 1XA by a predetermined fixed delay amount FD, and is, for example,
The delay circuit is a monostable multivibrator, and supplies the delayed fixed delay signal 12XA to the transmission circuit 2.

In the case of the first embodiment of FIG. 1, the fixed delay line 12
The fixed delay amount of is set to the fixed delay amount FD corresponding to one cycle of the initial cycle T. Therefore, the fixed delay signal 12XA provided to the transmission circuit 2 is a promise waveform that is always delayed by the same fixed delay amount FD as the initial cycle T from the time of the variable cycle signal 1XA for each variable cycle TE, that is, Appears as a cycle signal.

Further, the correlation signal 13XA applied to one input of the multiplication circuit 11 appears as a promised waveform, that is, a monocycle signal for each variable period TE.

That is, since the transmission signal 2XA gives the transmission antenna 3 a signal of a promised waveform in which the detection period is sequentially extended by Δt and is delayed by the same fixed delay amount FD as the initial period T, the transmission signal 2XA is received. The received signal 10XA obtained by the signal 9XA (noise signal is omitted) similarly appears as a signal delayed by Δt for each time,
The correlation signal 13XA is always delayed by the initial period T.

Therefore, the promise waveform signal applied to one input side of the multiplication circuit 11, that is, the correlation signal 13XA.
From the viewpoint, the received signal 10XA given as the correlated signal to the other multiplication input becomes a signal delayed by a time corresponding to the initial period T for each variable period TE, so that the correlation after the second variable period TE is correlated. Since the signal 13XA is delayed first, and the received signal 10XA is received at the time when it is sequentially advanced by Δt for each time of the variable period TE, the received signal 10XA is received with respect to the promised waveform of the correlation signal 13XA. Signal 10a.1 by underground buried objects 7A, 7B, 7C
0b and 10c will appear at the time when they are sequentially advanced by Δt.

Therefore, in the multiplication signal 11XA, the correlation signal 13XA with respect to the reception signal 10XA is shifted backward by Δt for each variable period TE, that is, for each detection period.
Since it is obtained as a signal of an amplitude value obtained by multiplying the amplitude value of each signal, the multiplication signal 11XA / integration signal 14XA /
As the detection signal 15XA, a detection signal subjected to the correlation detection processing and the pulse compression processing is obtained.

The variable period TE is the first fixed period T.
When the cycle becomes twice as long, the correlation detection process and the pulse compression process for the detection distance range corresponding to the first fixed cycle T are completed.

In the first embodiment of FIG. 1, the fixed delay circuit 12
Is provided between the variable period circuit 1X and the transmission circuit 2 so as to perform fixed delay. However, the fixed delay circuit 12 is removed, and the fixed delay circuit 12 is provided between the receiving antenna 9 and the amplifier circuit 10. Alternatively, even if the received signal 9XA or the received signal 10XA is fixedly delayed by being provided between the amplifier circuit 10 and the multiplication circuit 11, the correlated signal, that is, the received signal 10XA given to the multiplication circuit 11 is provided. The time relationship between the correlation signal 13XA and the correlation signal 13XA is the same as that in the embodiment of FIG. 1, and a detection signal obtained by performing the same correlation detection processing and pulse compression processing can be obtained.

Further, in the case of the detecting device for performing underground exploration by the transmitted wave as shown in FIG. 6, the transmitting side circuit section 50, control / control /
The correlation signal 1 is provided by the variable period circuit 1X, the correlation signal circuit 13, and the fixed delay path 12 provided in any of the display circuit units 70.
3XA and the fixed delay signal 12XA are obtained, and the multiplication circuit 11 provided in the receiving side circuit unit 60 or the control / display unit 70 obtains the multiplication signal 11XA, thereby performing the correlation detection process and the pulse compression process. The detection signal 15XA obtained by the above is obtained, or in the same configuration, the fixed delay path 12 is connected to the receiving antenna 9 and the receiving side circuit unit 6
The same correlation detection processing can be performed by arranging it between the receiving circuit 10 of 0 and the receiving circuit 10 and the multiplying circuit 11 provided in the receiving circuit unit 60 or the control / display circuit unit 70. It is possible to obtain a detection signal that has undergone pulse compression processing.

Further, in the case of the above correlation type signal detection device, the correlated signal including the signal of the promised waveform is converted to the correlated signal having the variable period TE and is also applied to the fixed delay circuit 12 and fixed. Correlation detection processing and pulse compression processing are performed by applying the delayed delayed correlated signal and the correlation signal having the promised waveform having the variable period TE to the multiplication circuit 11 to obtain a signal corresponding to the multiplication signal 11XA. The correlation detection signal obtained by performing

Next, a second embodiment in which the variable cycle TE of the variable cycle circuit 1X according to the first embodiment is sequentially shortened by a small amount of time .DELTA.t will be described with reference to FIG.

In the case of the second embodiment of FIG. 3, the variable period circuit 1X is changed to a variable period circuit 1Y which generates a shortened change type variable period signal 1YA as compared with the first embodiment of FIG. While giving the periodic signal 1YA to the transmission circuit 2,
The fixed delay circuit 12 includes a variable period circuit 1Y and a correlation signal circuit 1
3 is the same as that of the first embodiment shown in FIG.

In the variable period signal 1YA, the initial period TS is set to T + Δt × n as shown in FIG. 4, and the change of the portion of Δt × n is started from Δt × n and t × (n-1). , Δt × (n-
2), Δt × (n−3), ..., The variable period TE is gradually reduced and shortened. Further, the fixed delay amount FD of the fixed delay circuit 12 is T + Δt, which is the same as the initial period TS.
It is set to × n.

Therefore, the transmission signal 2YA output from the transmission circuit 2 and the reception signal 1 output from the reception circuit 10
0YA and the correlation signal 13 output from the correlation signal circuit 13
The relative time relationship with YA is as shown in FIG.
In the case of, the fixed delay time FD has a time relationship such that it is simply changed to T + Δt × n.
1 multiplication signal 11YA, integration circuit 14 integration signal 14Y
A, since the detection signal 15YA of the sample holding circuit 15 has the same time relationship, if T = Δt × n, the detection signal 15YA should be the same signal as the detection signal 15XA in FIG. become.

Further, the same correlation detection structure as that of the second embodiment is used in the case of the above-mentioned structure of the transmission / reception opposite detection, or
It goes without saying that the present invention can also be applied to the case of the above correlation type signal detection device.

[Modified Implementation] The present invention can be implemented by modifying as follows. (1) Amplified waveform described in the section of the prior art, amplitude change, frequency change, phase change, pulse number, pulse interval, etc. Waveforms with specific promises to, for example, waveforms with staircase amplitude format / equal waveform repeat format, or with staircase frequency modulation format / linear frequency modulation format / code phase modulation format / code carrier modulation format It is configured by using any of the waveforms such as.

(2) A pulse wave obtained by modulating the signal of the promised waveform into a rectangular shape of a single high frequency used in a general radar or a fish finder, that is, the f1 portion of the waveform of (a) in FIG. Make only the waveform.

(3) The initial period T of the variable period TE and the fixed delay amount FD of the fixed delay circuit 12 in the first embodiment shown in FIG.
Is set to N × T times N times, and the correlation detection process and the pulse compression process similar to those in the embodiment of FIG. 1 are performed.

(4) The initial period TS of the variable period TE and the fixed delay amount FD T + Δt × n in the second embodiment shown in FIG. 3 is T × ΔT × Δt × N = N × T + Δt × When n is set, the correlation detection process and the pulse compression process similar to those in the embodiment of FIG. 3 are performed.

(5) Instead of the initial period T of the variable period TE in the first embodiment of FIG. 1, a time amount obtained by adding an arbitrary time amount of T or less to the initial period T, or 0 or an arbitrary amount of T or less. By setting the amount of time of the above as the initial cycle, a so-called detection range is shifted, and the correlation detection processing is performed from the time corresponding to the target detection target, for example, the underground buried object 7B, for example, It is configured to obtain the detection signal 15XA for the underground buried objects 7B and 7C.

(6) The same operation as the shift of the detection range in (5) above with T or Δt × n in the initial period TS in the second embodiment of FIG. 3 being set to an arbitrary amount of time equal to or less than T. To perform.

(7) Fixed delay amount FD of fixed delay circuit 12
Is an initial period T or TS, which is an arbitrary time amount of T or Δt × n or less, or a delay amount obtained by adding an arbitrary time amount of T or Δt × n or less. For example, as shown in FIG. By setting a fixed delay amount corresponding to the delay amount of T × 0.6, a so-called detection range shift is performed, and the correlation is performed from the time corresponding to the target detection target, for example, the underground buried object 7B. The detection processing is performed, and for example, the detection signal 15XA for the underground buried objects 7B and 7C is obtained.

(8) Correlation signal 13 given to the multiplication circuit 11
The XA waveform is set to a waveform close to a model that can be deformed while the promise waveform on the transmitting side passes through the paths of the transmitting circuit 2, the transmitting antenna 3, the transmitting electromagnetic wave 4, the ground, the reflected electromagnetic wave 8, and the receiving antenna 9. For the purpose, a circuit corresponding to the waveform thereof, for example, a combination of a resonance circuit having a low Q and a phase shift circuit is interposed between the correlation signal circuit 13 or between the correlation circuit 13 and the multiplication circuit 11.

(9) The integrating circuit 14 is an operational type integrating circuit, and the sampling time of the sample holding circuit 15 is set at each time of the variable period signal 1XA or 1YA. In this case, needless to say, it is necessary to reset the calculation after sampling.

(10) In the above configuration (9), the digital value obtained by A / D converting the amplitude value obtained at each sampling time is stored in a storage circuit such as a memory or a shift register, and an address or shift is performed at each sampling time. Are moved to the next order and stored, and the detection contents 15XA or 15YA are obtained based on the digital value read out at the clock of a predetermined constant speed, so that the detection signal 15 due to the deviation of the sampling time point is detected.
Be able to correct XA or 15YA waveform distortion. Further, when the detection signal or the detection signal is obtained in the reverse time series described above, the stored contents are read out in the reverse order to obtain the signal in the normal time series.

(11) The integrating circuit 14 and the sample holding circuit 15 are eliminated, and the multiplication signal 1 is obtained by the low-pass filtering circuit.
Detection signal 1 by filtering 1XA or 11YA
5XA or 15YA is obtained. In this case, the variable period TE
Frequency corresponding to the initial period T of, that is, (1 / T) H
It is desirable to configure the filter circuit to pass frequencies of about z or less.

(12) The small amount of time Δt is constituted by another analog form, for example, the time to the clip level point of the rising or falling ramp wave is changed by changing the unit clip level.

(13) Form of promised waveform and small amount of time Δ
The quantity of t or either of them is constituted by a signal in digital form, for example a serial pulse signal or a parallel pulse representing a binary value.

(14) Form of promised waveform and small amount of time Δ
The amount of t or any one of them is converted into an analog signal, which is converted into a digital signal for correlation.

(15) Form of promised waveform and small amount of time Δ
The amount of t or any one of them is converted into a digital signal, which is then converted into an analog signal for correlation.

(16) Received signal 10XA or 10Y
A, the correlation signal 13XA or 13YA is A / D converted and digitized, and the variable period circuit 1X or 1
Y, multiplication circuit 11, integration circuit 14, sample holding circuit 1
Processing such as 5 is processed by a digital computer, for example, a microcomputer.

(17) Received signal 10XA or 10YA input to the multiplication circuit 11 and correlation signal 13XA or 1
An adjusting circuit for variably adjusting the amplitude to ensure the multiplication function, for example, a variable attenuating circuit is provided in both or one of the circuits 3YA and 3YA.

(17) Correlation signal 13XA or 13YA
In the case of a signal having a low frequency component, the multiplication circuit 11 is configured by a combination of operational amplifier circuits, for example, a multiplication IC.

[0051]

According to the present invention, the received signal including the promised waveform is used as the correlated signal, and the promised waveform obtained by sequentially shifting the received signal by a small amount of time is obtained as the correlation signal. Since the target detection signal or the correlation detection signal is obtained by performing the correlation detection processing and the pulse compression processing on the basis of the received signal, the detection signal or the correlation detection signal with a high S / N ratio and high accuracy can be obtained. There is a feature that the obtained product can be provided with a simple configuration in which only a variable period circuit and a fixed delay circuit are provided.

[Brief description of drawings]

 The figures show examples, and the content of each figure is as follows.

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of essential parts of the first embodiment of the present invention.

FIG. 3 is a block configuration diagram of a second embodiment of the present invention.

FIG. 4 is an operation waveform diagram of essential parts of a second embodiment of the present invention.

FIG. 5 is an operation waveform diagram of essential parts of a modified embodiment of the present invention.

FIG. 6 is a block diagram of a conventional technique.

FIG. 7 is a signal waveform diagram of essential parts of a conventional technique.

FIG. 8 is a signal waveform diagram of the prior art.

[Explanation of symbols]

 1X Detection Period Circuit 1XA Detection Period Signal 1Y Detection Period Circuit 1YA Detection Period Signal 2 Transmission Circuit 21 Transmission Waveform Circuit 22 Power Amplification Circuit 2XA Transmission Signal 2YA Transmission Signal 3 Transmission Antenna 4 Transmission Electromagnetic Wave 5 Ground Surface 6 Underground 7A ・ 7B ・ 7C Underground buried object 8 Reflected electromagnetic wave 9 Reception antenna 9XA Received signal 9YA Received signal 10 Amplification circuit 10XA Received signal 10YA Received signal 11 Multiplier circuit 11XA Multiplied signal 11YA Multiplied signal 12 Variable delay circuit 12XA Delay signal 12YA Delay signal 13 Correlation signal circuit 13XA correlation signal 13YA correlation signal 14 integration circuit 14XA integration signal 14YA integration signal 15 low-pass filtering circuit 15XA detection signal 15YA detection signal 16 display circuit 50 transmission side circuit unit 60 reception side circuit unit 70 control / display circuit unit 100 underground survey Radar

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[Procedure amendment]

[Submission date] February 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction content]

[0051]

According to the present invention, the received signal including the promised waveform is used as the correlated signal, and the promised waveform obtained by sequentially shifting the received signal by a small amount of time is obtained as the correlation signal. Since the target detection signal or the correlation detection signal is obtained by performing the correlation detection processing and the pulse compression processing on the basis of the received signal, the detection signal or the correlation detection signal with a high S / N ratio and high accuracy can be obtained. There is a feature that the obtained product can be provided with a simple configuration in which only a variable period circuit and a fixed delay circuit are provided.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief explanation of the drawing

[Correction method] Added

[Correction content]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show examples, and the contents of each drawing are as follows.

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of essential parts of the first embodiment of the present invention.

FIG. 3 is a block configuration diagram of a second embodiment of the present invention.

FIG. 4 is an operation waveform diagram of essential parts of a second embodiment of the present invention.

FIG. 5 is an operation waveform diagram of essential parts of a modified embodiment of the present invention.

FIG. 6 is a block diagram of a conventional technique.

FIG. 7 is a signal waveform diagram of essential parts of a conventional technique.

FIG. 8 is a signal waveform diagram of the prior art.

[Explanation of symbols]   1X   Detection periodic circuit   1XA   Detection period signal   1Y   Detection periodic circuit   1 YA   Detection period signal   Two   Transmission circuit   21   Transmit waveform circuit   22   Power amplifier circuit   2XA   Transmission signal   2YA   Transmission signal   Three   Transmitting antenna   Four   Transmission electromagnetic wave   5   Ground surface   6   Underground   7A / 7B / 7C   Underground objects   8   Reflected electromagnetic wave   9   Receiving antenna   9XA   Received signal   9YA   Received signal   10   Amplifier circuit   10XA   Received signal   10YA   Received signal   11   Multiplication circuit   11XA   Multiplication signal   11YA   Multiplication signal   12   Variable delay circuit   12XA   Delayed signal   12YA   Delayed signal   Thirteen   Correlation signal circuit   13XA   Correlation signal   13YA   Correlation signal   14   Integrator circuit   14XA   Integrated signal   14YA   Integrated signal   15   Low pass filter   15XA   Detection signal   15YA   Detection signal   16   Display circuit   Fifty   Transmission side circuit   60   Receiver side circuit   70   Control / display circuit   100   Underground exploration radar

Claims (8)

[Claims] 1. A correlation type detection device for obtaining a required detection signal by correlating a reception signal of a reflected wave or a transmission wave obtained by transmitting a transmission signal of a promise waveform repeated at a predetermined cycle with the promise waveform. Variable cycle means for obtaining a variable cycle by sequentially extending the cycle by a small amount of time each time, and fixed delay transmission means for performing the transmission at each time when a predetermined fixed delay amount is added to each variable cycle. , Variable period correlation signal means for obtaining the signal of the promised waveform as a correlation signal for each of the variable periods, and the detection signal based on a multiplication signal obtained by multiplying the received signal by the correlation signal as a correlated signal. A variable period correlation type detection device, comprising: 2. A correlation-type detection device for obtaining a required detection signal by correlating a reception signal of a reflected wave or a transmission wave obtained by transmitting a transmission signal of a promise waveform repeated at a predetermined cycle with the promise waveform. A variable cycle means for obtaining a variable cycle by sequentially shortening the cycle by a small amount of time each time, a variable cycle transmitting means for performing the transmission according to the variable cycle, and a predetermined fixed delay amount for each variable cycle. Fixed delay correlation signal means for obtaining the signal of the promised waveform as a correlation signal at each added time point, and multiplication for obtaining the detection signal based on a multiplication signal obtained by multiplying the received signal by the correlation signal as a correlated signal A variable period correlation type detection device comprising: 3. The variable period correlation detection apparatus according to claim 1, further comprising the multiplication means for performing the multiplication by an analog value. 4. The variable period correlation type detection device according to claim 1, further comprising: the multiplication means for performing the multiplication by a digital value. 5. A correlation type signal detection device for obtaining a required detection signal by correlating a received signal including a signal of a promise waveform which repeats at a required cycle with the promise waveform, wherein the cycle is performed every time. Variable cycle means for obtaining a variable cycle that is sequentially extended by a small amount of time, fixed delay receiving means for obtaining the received signal whose starting point is the time when a predetermined fixed delay amount is added to each variable cycle, Variable period correlation signal means for obtaining a signal of the promised waveform as a correlation signal for each variable period, and multiplication means for obtaining the detection signal based on a multiplication signal obtained by multiplying the received signal as a correlated signal by the correlation signal. And a variable period correlation type signal detection device. 6. A correlation type signal detection device for obtaining a required detection signal by correlating a received signal including a signal of a promise waveform which repeats at a required cycle with the promise waveform, wherein the cycle is repeated every time. Variable period means for obtaining a variable period which is sequentially shortened by a small amount of time, variable period reception signal means for obtaining the received signal having the variable period, and at each time point when a predetermined fixed delay amount is added to each variable period. Fixed delay correlation signal means for obtaining the signal of the promised waveform as a correlation signal, and multiplication means for obtaining the detection signal based on a multiplication signal obtained by multiplying the received signal as a correlated signal with the correlation signal. A variable period correlation type signal detection device characterized by the above. 7. The variable period correlation type signal detection device according to claim 5, further comprising the multiplication means for performing the multiplication by an analog value. 8. The variable period correlation type signal detection device according to claim 5, further comprising the multiplication means for performing the multiplication by a digital value.