JP2011196856A - Pulse radar device, object detection method of the same, and detection processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse radar device shortening a time required for beam scanning in one direction, and detecting a primary echo surely without erroneous discrimination with a secondary trip echo.

SOLUTION: An initial phase of an N pulse portion is generated with a reference variation ϕ1 by a pulse phase setter 11, and N transmission pulse trains are generated and transmitted by a transmission pulse generator 12. A target signal is detected by treating reception signals in the N pulse portion reflected by the target as one set. Similarly, a target signal is detected relative to a reference variation ϕ2. The reception signal is corrected by a phase reverse to the initial phase, and a phase rotation amount of the corrected reception signal is compared to remove the secondary trip echo, the primary echo is detected, and the target data are outputted.

COPYRIGHT: (C)2012,JPO&INPIT

Description

  The present invention relates to a pulse radar device in which a false target is generated by a secondary trip echo, a target detection method of the pulse radar device, and a detection processing program.

  A radar apparatus generally detects the presence of a target by irradiating a radio wave to the space and receives a reflected signal from the target, and observes its position, velocity, and the like. The radio wave is emitted from an antenna provided in the radar apparatus. The radio wave irradiated from the antenna forms a radio wave beam having a predetermined shape in the space, and scans the space while sequentially changing the direction of the radio wave beam. A pulse radar device is a radar device that irradiates a space with a pulse, and based on the difference between the time when a transmission pulse is emitted from an antenna and the time when a received pulse reflected by the target is received by the antenna, Measuring distance.

  In the pulse radar device, in order to be able to detect a smaller target, pulse compression that transmits a modulated long pulse and performs correlation processing with the transmission pulse waveform at the time of reception, or a set of multiple pulses in the same direction An integration process is generally performed in which signals transmitted as pulse trains and signals of the same distance are added together. By performing these processes, the S / N is improved even in the case of a reflected signal from a small target, and the detection can be performed within a predetermined distance range.

  The interval at which the transmission pulse is output is called a pulse repetition period, but the range in which the detection distance can be accurately measured generally depends on the pulse repetition period. For example, when a reception pulse corresponding to a certain transmission pulse is received before the transmission timing of the next transmission pulse, the detection distance can be accurately measured. This is called primary echo (primary reflected wave). On the other hand, when the reception pulse corresponding to the transmission pulse is received after the transmission timing of the next transmission pulse, it can be distinguished whether the reception pulse corresponds to the next transmission pulse. Therefore, it is measured as a short distance rather than an actual distance. This is a phenomenon called secondary trip echo. In addition, the received pulse may be received at a later transmission pulse timing, and in this case, a far target is measured as a short distance. The phenomenon in which the measured target distance is indefinite is called range ambiguity.

  As means generally known for avoiding this phenomenon, for example, there is one that employs a plurality of different pulse repetition periods (Non-Patent Document 1). In the case of the primary echo, the distance to the target is measured at the same distance even if the pulse repetition period is different. In the case of the secondary trip echo, if the pulse repetition period is different, the distance to the target is measured. This utilizes the phenomenon that the distance is measured as a different distance. That is, if the distance to the target measured for each pulse repetition period is compared, the primary echo and the secondary trip echo can be separated, and the primary echo can be detected correctly.

  Further, as another means for avoiding the above-described phenomenon, there is one that performs phase modulation for each transmission pulse to suppress the secondary trip echo (Patent Document 1). FIG. 7 is a block diagram showing the technology of the radar apparatus described in Patent Document 1. The pulse phase controller (2) 71 randomly generates the initial phase of the transmission pulse. The transmission pulse generator 72 generates a transmission pulse set by the initial phase generated by the pulse phase controller (2) 71 and outputs the transmission pulse to the transmitter 73. The transmitter 73 frequency-converts the transmission pulse to RF and amplifies the power, and then outputs it to the antenna 75 via the transmission / reception switch 74.

  Subsequently, the aerial line 75 emits a transmission pulse as a radio wave to the space at the time of transmission, and receives a radio wave input from the space at the time of reception and outputs it to the receiver 76 via the transmission / reception switch 74. The transmission / reception switch 74 switches the input / output directions of the transmission signal and the reception signal at the timing of transmission and reception. The receiver 76 frequency-converts the RF reception signal, A / D-converts and phase-detects it, and outputs it to the pulse compressor 77. The pulse compressor 77 performs correlation processing between the reception signal and the transmission pulse waveform. The pulse phase corrector (1) 78 performs phase correction so that the S / N is improved upon integration of the secondary trip echo and outputs it to the integration processor 79.

  The received signal whose S / N is improved by integration by the integration processor 79 is compared with a predetermined threshold value by the secondary trip echo detector 80. As a result, a signal having a large amplitude is converted to the secondary trip echo. It is determined and detected. The secondary trip echo remover 81 removes the secondary trip echo by subtracting the signal component of the detected secondary trip echo from the received signal. The pulse phase corrector (2) 82 performs correction opposite to the correction performed by the pulse phase corrector (1) 78 on the received signal after removing the secondary trip echo, and then the primary echo is Phase correction is performed so that S / N is improved during integration. Subsequently, after integration processing is performed by the integration processor 83, the target detector 84 compares it with a predetermined threshold value. As a result, a signal having a large amplitude is determined as the target of the primary echo and output as target data. The

  That is, in this radar apparatus technology, the initial phase of the transmission pulse is randomly modulated and transmitted, and phase correction is performed so that the secondary trip echo is first integrated with respect to the received signal. To detect. Then, after subtracting the signal component of the detected secondary trip echo from the received signal, the received signal is phase-corrected and integrated so that the primary echo is integrated. As a result, the secondary trip echo is removed and only the primary echo is output.

  Further, as a related radar device technique, after the dominant frequency component is removed from the received signal that has been subjected to the first phase correction so as to cancel the phase of the transmission wave transmitted a predetermined time ago, the first frequency There is a technique in which signal processing is performed so as to obtain a reception signal for measurement by performing phase correction and phase correction, and further performing second phase correction so as to cancel the initial phase of the transmission wave (Cited document 2). .

Merrill Skolnik, “Radar Handbook Third Edition”, McGraw-Hill, p.4.31-4.34 Japanese Patent Laid-Open No. 08-146124 JP 2009-36540 A

  However, since the technique disclosed in Non-Patent Document 1 outputs transmission pulses at a plurality of different pulse repetition periods, the time required for beam scanning in one direction is output at a single pulse repetition period. There was a drawback that it was longer than twice as long. This is because at least two types of pulse repetition periods with different values are transmitted, and the repetition period needs to be equal to or longer than the pulse repetition period determined by the distance of the maximum processing of the radar device. Because it ends up.

  Further, in the technique disclosed in Patent Document 1, since the phase correction amount occurs randomly, the difference in amplitude after integration of the primary echo and the secondary trip echo may be small due to fluctuations in the target signal, etc. In some cases, the primary echo is removed as a secondary trip echo, or the secondary trip echo is detected as a primary echo. Further, the technique disclosed in Patent Document 2 has a drawback in that it cannot be reliably detected when the difference in amplitude between the integrated primary echo and the secondary trip echo is small.

[Object of invention]
Therefore, the present invention has been made in view of such circumstances, and shortens the time required for beam scanning in one direction and reliably detects the primary echo without making a mistake in discriminating it from the secondary trip echo. An object of the present invention is to provide a pulse radar device, a target detection method for the pulse radar device, and a detection processing program.

In order to solve the above problems, a pulse radar device according to the present invention includes a transmission pulse generator that generates transmission pulses for radar waves,
A transmitter for amplifying the transmission pulse generated by the transmission pulse generator and transmitting it as a radar wave via an antenna;
A pulse radar for receiving a reflected radar wave from a target received via the antenna as a received signal, identifying a primary echo from the received received signal, and outputting this as target data In the device
The transmission pulse generator is energized to sequentially generate two sets of transmission pulse trains of one and the other as the pulses for the radar wave with different reference phase amounts and equal pulse repetition periods and pulse numbers. Provide a pulse phase setting unit to
In addition to the receiver, a pulse phase corrector that corrects the phase of the reception signal at the reception timing corresponding to the transmission pulse in a phase opposite to the initial phase set in the transmission pulse by the pulse phase setting unit,
The pulse phase corrector is provided with a secondary trip echo canceller for removing the secondary trip echo from the received signal and detecting the primary echo based on the phase of the received signal after the phase correction. It is characterized by.

In order to solve the above problems, a target detection method for a pulse radar device according to the present invention includes a transmission pulse generator that generates a transmission pulse for a radar wave, and a transmission pulse generated by the transmission pulse generator. And a receiver for receiving a reflected radar wave from a target received via the antenna as a received signal, and 1 from the received received signal. A target detection method of a pulse radar device that identifies a next echo and outputs it as target data,
The pulse phase setting unit provided in the transmission pulse generator sequentially generates one and the other two sets of transmission pulse trains having different reference phase amounts and the same pulse repetition period and number of pulses as the pulses for the radar wave. Energizing the transmit pulse generator to
The pulse phase corrector provided in the receiver corrects the phase of the reception signal at the reception timing corresponding to the transmission pulse with a phase opposite to the initial phase set for the transmission pulse in the pulse phase setting unit,
Each step of removing the secondary trip echo from the received signal based on the phase of the received signal after the phase correction is performed, detecting the primary echo, and removing and detecting the primary echo is provided in the pulse phase corrector. The second-order trip echo canceller is executed.

In order to solve the above problem, a target detection processing program for a pulse radar apparatus according to the present invention includes a transmission pulse generator that generates a transmission pulse for radar waves, and a transmission generated by the transmission pulse generator. A transmitter that amplifies a pulse and transmits it as a radar wave via an antenna; and a receiver that captures a reflected radar wave from a target received via the antenna as a received signal, from the captured received signal A target detection processing program for a pulse radar device that identifies a primary echo and outputs it as target data,
A pulse phase setting function for energizing the transmission pulse generator so as to sequentially generate two sets of transmission pulse trains having different reference phase amounts and the same pulse repetition period and number of pulses as the pulses for the radar wave;
A pulse phase correction function for correcting the phase of the reception signal at the reception timing corresponding to the transmission pulse with a phase opposite to the initial phase set for the transmission pulse in the pulse phase setting unit;
A secondary trip echo cancellation function for removing the secondary trip echo from the received signal and detecting the primary echo based on the phase of the received signal after the phase correction is performed;
Is realized by a computer.

  According to the present invention, by using two types of transmission pulse trains having different initial phases but the same pulse repetition period, the time required for transmitting the beam in one direction in a single pulse repetition period can be reduced. It can be reduced to 2 times. In addition, the received signal is corrected with a phase opposite to the initial phase set for the transmission pulse, so that the phase rotation amount is not canceled by orders other than the primary echo (second order, third order,...) Echo. Therefore, the primary echo can be reliably detected without removing the primary echo as the secondary trip echo or detecting the secondary trip echo as the primary echo.

1 is a block diagram showing a first embodiment of a pulse radar device according to the present invention. It is the schematic diagram which showed the response | compatibility of the phase of a primary echo and a secondary trip echo. It is a timing chart which shows the relationship between the timing and phase of a transmission pulse train. It is a schematic diagram explaining the Doppler frequency of a received signal. It is a block diagram which shows 2nd Embodiment of the pulse radar apparatus which concerns on this invention. It is a block diagram which shows 3rd Embodiment of the pulse radar apparatus which concerns on this invention. It is a block diagram which shows the structure of the conventional radar apparatus.

[First Embodiment]
Embodiments of a pulse radar device according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a first embodiment of a pulse radar device in a radar device. The pulse radar device 1 generates two types of reference phase amounts, and generates a pulse phase setter 11 that controls the initial phase of a transmission pulse train corresponding to each of the reference phase amounts, and a transmission pulse that controls the initial phase, and sends it to the transmitter. A transmission pulse generator 12 for output, a transmitter 13 for converting the frequency of the transmission pulse to RF and then outputting it to the antenna 15 via the transmission / reception switch 14, and transmission / reception for switching the input / output directions of the transmission signal and the reception signal A switch 14; an antenna 15 that emits a transmission pulse and receives an input radio wave; a receiver 16 that converts the frequency of an RF reception signal input from the antenna 15 via the transmission / reception switch 14; A pulse compressor 17 that performs correlation processing between a signal and a transmission pulse waveform, a pulse phase corrector 18 that corrects the phase of the received signal, and the waveform structure of the received signal does not change An integration processor 19 for coherent integration, a target detector 20 for detecting a target signal from the received signal output from the integration processor 19, a memory 21 for storing a Doppler filter number at the time of integration processing of the target signal, A secondary trip echo canceller 22 that compares the Doppler filter number of the target signal and removes the secondary trip echo is configured.

  The pulse phase setter 11 performs control for generating two types of reference phase amounts (reference change amounts) and setting initial phases of two sets of transmission pulse trains (for N pulses) corresponding to the respective reference phase amounts. Yes. This initial phase control is performed such that a Doppler frequency, that is, an apparent speed, which is an apparent frequency difference is added to a secondary trip echo received as a reflected wave. In addition, two types of transmission pulse trains having different initial phases but the same pulse repetition period are used. The pulse phase setter energizes the transmission pulse generator 12 so as to sequentially generate two sets of transmission pulse trains having different reference phase amounts and the other as a pulse for the radar wave. Therefore, the pulse generator may be provided as a pulse phase setting unit.

The transmission pulse generator 12 generates a transmission pulse whose initial phase is controlled and outputs the transmission pulse to the transmitter 13.
The transmitter 13 frequency-converts the input transmission pulse to RF by a frequency conversion circuit, further amplifies the power by a power amplifier, and then outputs it to the antenna 15 via the transmission / reception switch 14.

The transmission / reception switcher 14 switches the input / output directions of the transmission signal and the reception signal at the timing of transmission and reception.
The antenna 15 emits a transmission pulse as a radio wave to the space at the time of transmission, and receives a radio wave input from the space at the time of reception.

The receiver 16 frequency-converts the RF reception signal input from the antenna 15 via the transmission / reception switch 14 by a frequency conversion circuit, and further performs A / D conversion by the A / D conversion circuit, and then a phase detection circuit. Is used to perform phase detection.
The pulse compressor 17 performs a pulse compression process, which is a correlation process between the received signals output from the receiver 16 (N received signals are one set) and the transmitted pulse waveform output from the transmitter 13.

  The pulse phase corrector 18 performs a process of correcting the phase of the received signal in order to cancel the initial phase set as the transmission pulse in the pulse phase setting unit 11 in the received signal at the reception timing corresponding to the transmission pulse.

  The integration processor 19 considers the phase of the received signal for each transmission pulse train output from the pulse phase corrector 18 and performs coherent integration so that the structure of the signal waveform does not change. Coherent integration is a process for improving S / N by adding the amplitude (complex number) of received pulses received corresponding to transmission pulses having the same repetition period. The amplitude of the received pulse is a complex number and rotates at a speed corresponding to the target speed. Coherent integration can be expressed as a digital filter by the following complex product-sum operation expression (1).

[Equation 1]
Yk = Σ (Wk, i · Xi) (1)
i: 1 ≦ i ≦ n, where n is the number of pulses transmitted in the same pulse repetition period = integration number k: Doppler filter number Wk, i: coefficient corresponding to Doppler filter number k Xi: complex of received pulse of i-th pulse Amplitude value

  The target detector 20 compares the received signal after integration processing output from the integration processor 19 with a predetermined threshold value, determines whether or not it is larger than this threshold value, and detects the target signal. The above processing is performed for each of the two sets of transmission pulse trains.

  The memory 21 stores the Doppler filter number of the Doppler filter bank at the time of integration processing of the target signal detected for each transmission pulse train.

  The secondary trip echo canceller 22 compares the Doppler filter numbers of the target signals detected as being the same distance among the target signals detected for each transmission pulse train by the target detector 20, and the Doppler filter numbers are different. If so, the signal is determined to be a secondary trip echo and removed. On the other hand, when the Doppler filter numbers are the same, the signal is determined to be a primary echo and the data is output as target data.

Next, functions of main parts constituting the pulse radar device 1 will be described in more detail with reference to FIGS.
The pulse phase setter 11 generates two types of reference change amounts φ1 and φ2 for beam scanning in one direction. In addition, the initial phase of two sets of transmission pulse trains (transmissions for N pulses) 61 and 62 corresponding to the respective reference variation amounts φ1 and φ2 is added with a Doppler frequency which is an apparent frequency difference with respect to the secondary trip echo. (See FIG. 3). Two types of transmission pulse trains having different initial phases but the same pulse repetition period are used.

  The pulse phase setter 11 sets the initial phase an (n: pulse number) to be set for each transmission pulse of the transmission pulse train as in the following equation (2), where φ is the reference change amount. The transmission pulse generator 12 outputs the transmission pulse train having the initial phase set as described above to the transmitter 13.

[Equation 2]
an = − {n (n−1) / 2} φ (2)

  As shown in FIG. 3, the initial phase set for each transmission pulse is 0, −φ1, −3φ1, −6φ1 (transmission pulse train 61) for the reference variation φ1, 0 for the reference variation φ2, φ2, −3φ2, and −6φ2 (transmission pulse train 62) are set. Two types of transmission pulse trains having different initial phases but the same pulse repetition period are used.

  On the other hand, the phase relationship between the primary echo 51 and the secondary trip echo 52 received as a reflected signal from the target is as shown in FIG. In the primary echo 51, the reception pulse corresponding to the transmission pulse is received before the transmission timing of the next transmission pulse, but in the secondary echo 52, the reception pulse corresponding to the transmission pulse is the transmission timing of the next transmission pulse. Has been received later.

The pulse phase corrector 18 corrects the received signal with a phase (correction amount 53) obtained by reversing the positive and negative phases from the initial phase set as described above.
As a result of the correction, since the primary echo is canceled by the correction by the phase (correction amount 53) whose polarity is opposite to that at the time of transmission, the phase rotation amount between the reception pulses depends only on the target moving speed. (54 and 64 after primary echo correction in FIGS. 2 and 3).

  On the other hand, since the correction amount 53 by the pulse phase corrector 18 is different from the phase of the received secondary trip echo (secondary echo 52), the secondary trip echo has a phase rotation amount between the received pulses. Will not be countered. That is, since the secondary trip echo corresponding to the transmission pulse with the pulse number n is received at the timing when the reception signal corresponding to the transmission pulse with the pulse number n + 1 is received, the phase after correction by the pulse phase corrector 18 ( 2 and 3 after the secondary echo correction 55 and 65) are expressed by the following equation (3).

[Equation 3]
bn + 1 = an−an + 1 = nφ (3)

  As represented by the equation (3), the secondary trip echo rotates by the phase rotation amount φ for each pulse. Therefore, the target is measured as having a Doppler (frequency difference between transmitted and received radio waves) in which the apparent speed is changed by the phase rotation amount φ in addition to the actual moving speed. When the phase of the received signal is corrected in this way, the amount of phase rotation between the received pulses differs between the primary echo and the secondary trip echo. Therefore, based on the phase of the received signal after correction, The secondary trip echo can be discriminated and the primary echo can be detected.

  Actually, when the integration processor 19 performs coherent integration in consideration of the phase, the integration result is calculated for each filter bank at a predetermined speed interval. The Doppler filter has a different count for each speed to be detected. A plurality of Doppler filters are arranged so that even a wide range of speed targets can be detected (a Doppler filter bank using a plurality of sets of coefficients), and the output of each Doppler filter is calculated in parallel processing. As a result, the speed of the target, that is, the filter output corresponding to the filter number corresponding to the Doppler frequency is detected at the maximum, so that the target speed can be known. At this time, the Doppler filter number corresponding to the actual velocity of the target is selected as the primary echo, but in the case of the secondary trip echo, the Doppler filter number shifted by the velocity corresponding to the phase rotation amount φ is Will be selected.

In the present invention, using this feature, the secondary trip echo is removed and the primary echo is detected.
As shown in FIG. 3, in the pulse radar device 1, the initial phase of the transmission pulse corresponding to the reference variation amounts φ1 and φ2 is set. First, the pulse phase setter 11 generates an initial phase for N pulses with the reference change amount φ1. The transmission pulse generator 12 generates N transmission pulses 61 and outputs them. After that, the received signal input to the antenna 15 as a reflected signal from the target is corrected, integrated, etc. with N received signals as one set, and then the target signal of the received signal is detected by the target detector 20. The

  Next, the reference change amount is changed to φ2 and, similar to the case of φ1, the target detector 20 after the generation of the initial phase for N pulses, the output of the N transmission pulses 62, the correction of the received signal, the integration, etc. To detect the target signal.

  The target signal that has been processed earlier and detected from the received signal corresponding to the reference change amount φ1 is temporarily detected until the target signal is detected from the received signal corresponding to the reference change amount φ2 by the next processing. Stored in the memory 21. When the target signal is detected from the received signal corresponding to the reference change amount φ2, the target signal stored in the memory 21 together with the target signal is input to the secondary trip echo canceller 22.

  At this time, if the target signal corresponding to the reference variation φ1 and the target signal corresponding to the reference variation φ2 are detected as a target signal of the same distance or a target signal within a certain distance difference, the primary echo and the secondary The trip echo Doppler filter number fb has the relationship shown in FIG. The target signal within a certain distance difference is because the distance error due to the accuracy of the radar device and the time difference exists between the first transmission pulse train and the second transmission pulse train, and the target moves between them. This is because there may be a difference in the distance of the detected target.

  In the case of the primary echo, the Doppler filter numbers of the target signals corresponding to the reference change amounts φ1 and φ2 are both detected at the Doppler filter number fbT 66B corresponding to the actual (true) target speed fdT 66A. On the other hand, in the case of the secondary trip echo, the Doppler filter number of the target signal corresponding to the reference change amount φ1 is detected at the Doppler filter number fb1 (Δfd1) 67B corresponding to the Doppler frequency fd1 67A, and the reference change amount The Doppler filter number of the target signal corresponding to φ2 is detected at the Doppler filter number fb2 (Δfd2) 68B corresponding to the Doppler frequency fd2 68A. That is, in the case of the secondary trip echo, it is detected at a Doppler filter number different from the Doppler filter number corresponding to the actual target speed (Doppler frequency).

  Thereby, the Doppler filter number of the target signal corresponding to the reference change amount φ1 and the Doppler filter number of the target signal corresponding to the reference change amount φ2 are compared, and if the difference between the numbers is within a certain range, the first order It is determined to be an echo and detected. On the other hand, if the number difference is greater than or equal to a certain range, it is determined that it is a secondary trip echo and is eliminated.

Next, the operation of the pulse radar device 1 according to the first embodiment will be described with reference to FIGS.
A reference phase amount (two types) of a signal transmitted from the pulse radar device 1 and an initial phase of the transmission pulse train are generated and set by the pulse phase setting unit 11. Two types of transmission pulse trains having different initial phases but the same pulse repetition period are used. The transmission pulse generation interval is determined in consideration of the ambiguity of the distance to the target. A transmission pulse train having an initial phase set by the pulse phase setter 11 is generated by the transmission pulse generator 12, and the generated transmission pulse train is output to the transmitter 13.

  Two types of transmission pulse trains having different reference phase amounts are frequency-converted to RF by a frequency converter provided in the transmitter 13 and are amplified by a power amplifier also provided in the transmitter 13. The power-amplified transmission pulse is output from the transmitter 13 and radiated from the antenna 15 to the space via the transmission / reception switch 14. The observation direction is changed by changing the beam direction in which the transmission pulse is emitted.

  Next, when the transmission pulse (transmission wave) radiated to the space is reflected by the target, it becomes a reflected wave and reaches the antenna 15 so that the antenna 15 receives this reflected wave. The received reflected wave (reception signal) is input to the receiver 16 via the transmission / reception switch 14. The received signal is frequency-converted to RF by a frequency converter provided in the receiver 16 and A / D converted by an A / D converter also provided in the receiver 16 and then phase information regarding the received signal is extracted. Therefore, phase detection is performed by a phase detection circuit provided in the receiver 16.

  The received signal output from the receiver 16 is input to the pulse compressor 17. The pulse compressor 17 performs a pulse compression process that is a correlation process between the input received signal and a transmission pulse waveform corresponding to the received signal. The pulse-compressed received signal is input to the pulse phase corrector 18 for phase correction processing. This correction processing is performed so that the initial phase set in the transmission pulse by the pulse phase setting unit 11 is canceled in the reception signal received at the reception timing corresponding to the transmission pulse.

  The corrected reception signal is input to the integration processor 19 and integrated coherently in consideration of the phase for each transmission pulse train included in the reception signal. The integrated received signal is input to the target detector 20 to perform target signal detection processing. In this detection processing, a predetermined threshold value is compared with the received signal after integration processing output from the integration processor 19, and a signal having an amplitude exceeding the threshold value is determined as a target signal and detected.

  A series of processes until the above-described target signal is detected is performed for each of the set transmission pulse trains of two types of reference phase amounts. Then, when the target signal is detected for the transmission pulse train of one reference phase amount, the Doppler filter number (the number at the time of the coherent integration process) of the target signal is the target signal for the transmission pulse train of the other reference phase amount. Until it is detected, it is stored in the memory 21.

  Subsequently, when the target signal is detected for the transmission pulse train of the other reference phase amount, the target signal and the target signal stored in the memory 21 are input to the secondary trip echo canceller 22. Among the target signals detected for each transmission pulse train, the Doppler filter numbers of the target signals detected as target signals within the same distance or a certain distance difference are compared, and when the Doppler filter numbers are different, the target signal is A secondary trip echo is determined and removed. On the other hand, when the drup filter numbers are the same, it is determined that the echo is a primary echo, and the information is output as target data.

  With the configuration and operation of the pulse radar device 1 as described above, the time required for beam scanning in one direction can be suppressed to twice the time required for transmitting a transmission pulse with a single pulse repetition period. It is possible to quickly grasp the position and speed thereof. This is because the use of two types of transmission pulse trains having different initial phases but the same pulse repetition period results in wasted time (more than necessary) compared to the case of using transmission pulse trains having different pulse repetition periods. This is because it is possible to prevent a long repetition period) from occurring.

  Further, the primary echo can be reliably detected without removing the primary echo as the secondary trip echo or detecting the secondary trip echo as the primary echo, and the distance to the target and its movement can be detected. Speed and the like can be accurately measured. This is because the initial phase of the transmission pulse train is set to a value calculated by a predetermined calculation formula and the initial phase is set by two types of reference phases having different apparent speeds of the secondary trip echo. Since the fact that the Doppler filter number at the time of integration of the target signal detected from the received signal corresponding to the reference phase is used is utilized, the primary echo and the secondary are not based on the amplitude value determination after integration but by the difference in the Doppler filter number. This is because the trip echo is separated.

[Second Embodiment]
Next, a second embodiment of the pulse radar device will be described with reference to FIG. The same reference numerals as those in the first embodiment shown in FIG. 1 have the same functions and operations.
The pulse radar device 2 includes a speed difference detector 31 and a distance corrector 32 instead of the secondary trip echo remover 22 in the first embodiment of FIG.

  Also in the pulse radar device 2, as shown in FIG. 2, the secondary trip echo (after secondary echo correction 55) rotates by the phase φ every time the pulse number increases. A speed corresponding to this phase rotation amount φ is added as an apparent speed and observed. On the other hand, the reception pulse received at the reception timing two times after the transmission pulse becomes the tertiary echo 56. In the case of the tertiary echo, the phase is rotated by 2φ every time the pulse number increases (57 after the third echo correction). Therefore, a speed corresponding to the rotation amount 2φ is observed as an apparent speed.

  Therefore, the added speed is different between the secondary trip echo and the tertiary trip echo, and it is possible to distinguish both in this respect. The same applies to the fourth and subsequent orders. For example, in the case of the fourth order, the phase rotation amount is 3φ for each pulse number, and a speed corresponding to the rotation amount 3φ is added.

  The speed difference detector 31 includes two sets of transmission pulse trains corresponding to two sets of transmission pulse trains having different reference phase amounts in the received reception signals (the initial phase is different but the pulse repetition surroundings and included) A signal superposition processing unit is provided that performs superposition processing in accordance with transmission timings of two types of transmission pulse trains having the same number of pulses. Further, the transmission difference detector 31 includes an echo order specifying unit that specifies a speed difference of each of the plurality of secondary echoes obtained by the function of the signal superposition processing unit, and specifying what order the echo is based on the primary echo. I have. Further, the speed difference detector 31 outputs the actually measured distance to the target for the primary echo and other order echoes at the output stage at the time from the transmission pulse transmission to the reception pulse reception. And a distance corrector that calculates the true distance to the target for the primary echo by correcting the distance for the other order with respect to the distance for the echo of the other order.

  As in the case of the first embodiment, the target detector 20 detects a target signal for each of two types of transmission pulse trains of reference phase amounts. When a target signal is detected for a transmission pulse train of one reference phase amount, information on the target signal is stored in the memory 21 until a target signal for the transmission pulse train of the other reference phase amount is detected. The

  When the target signal is detected for the transmission pulse train of the other reference phase amount, the target signal and the target signal stored in the memory 21 are input to the speed difference detector 31. The speed difference detector 31 determines the order of echoes of each target signal based on the difference in speed between the detected target signals.

  The target signal and its determination are input to the distance corrector 32. The distance corrector 32 corrects the distance corresponding to the determined order with respect to the actually measured distance obtained from each target signal. Then, the true distance to the target obtained by this is calculated and output as target data. By performing such processing, in the first embodiment, the secondary trip echo is simply removed and the primary echo is detected, but in the case of the second embodiment, the secondary or higher-order echo is detected. The distance (for example, the distance of the third-order and fourth-order echoes) can also be correctly measured and the target data can be output.

[Third Embodiment]
Next, a third embodiment of the pulse radar device will be described with reference to FIG. The same reference numerals as those in the first embodiment shown in FIG. 1 have the same functions and operations.
In the pulse radar device 3, a non-coherent integration processor 42 is added to the next stage of the integration processor 19 in the first embodiment of FIG. 1 and a memory (2) 41 is added instead of the memory 21. ing.

  Between the integration processor 19 and the target detector 20, the received signal processing data for each transmission pulse train and the received signal processing data for each other transmission pulse train output from the integration processor 19 are sent. A non-coherent integration processing unit 42 that performs amplitude addition is provided. The non-coherent integration processor 42 is equipped with a processing data storage (memory (2)) 41 in place of the reception signal storage (memory (1) 21 (FIG. 1)). In the processing data storage 41, processing data of the received signal for each one transmission pulse train output from the integration processor 19 (transmission transmitted earlier of two sets of transmission pulse trains transmitted before and after). (Received signal processing data of pulse train) is stored, and received signal processing data (received signal processing data of transmission pulse train transmitted earlier of two sets of transmission pulse trains) for each other transmission pulse train is output. Then, it is read out by the non-coherent integration processing unit 42 and non-coherent integration is performed.

  Similarly to the case of the first embodiment, the integration processor 19 performs coherent integration on the reception signal for each transmission pulse train. Then, in the memory (2) 41, the first time (the reception received earlier) of the integration processing results of the reception signals (reception signals corresponding to two sets of transmission pulse trains having different reference phase amounts) in the integration processor 19 Signal) is stored until the integration processing result of the second reception signal (reception signal received later) by the integration processor 19 is obtained. The stored data includes the Doppler filter number at the time of integration processing.

The non-coherent integration processor 42 receives data of the second integration processing result and data of the first integration processing result stored in the memory (2) 41. The non-coherent integration processor 42 performs non-coherent integration processing for adding the amplitudes of both input data.
The reception signal subjected to non-coherent integration is input to the target detector 20. As in the case of the first embodiment, the target detector 20 detects the target signal by threshold determination.

  The detected target signal is input to the secondary trip echo remover 22, and the secondary trip echo is removed based on the information relating to the processing data stored in the (memory (2)) 41. The Doppler filter number at the time of the non-coherent integration process is compared with the Doppler filter number of the first integration process result stored in the memory (2) 41, and if the Doppler filter number is different, the target signal Is determined to be a secondary trip echo and removed. On the other hand, when the drup filter numbers are the same, it is determined that the echo is a primary echo, and the information is output as target data.

  As described above, in the first embodiment, only the target detection process is performed based on the N pulse integration process result. However, in the third embodiment, each N pulse integration process result is further converted to a non-coherent integration process. After processing, target detection processing is performed. Therefore, in the third embodiment, in addition to securing the detection performance by removing the secondary trip echo, it is possible to further secure the detection performance due to the gain of the non-coherent integration process.

  Also, all or part of the functions executed by each part of the embodiment of the pulse radar device according to the present invention may be constructed as a program, and the program may be executed by a computer. In this case, the same effect as that described in the above embodiment can be obtained.

  About each embodiment mentioned above, if the summary of the novel technical content is put together, it will become as follows. A part or all of the above-described embodiment is as follows as a novel technique, but the present invention is not necessarily limited to this.

(Supplementary note 1) a transmission pulse generator for generating transmission pulses for radar waves;
A transmitter for amplifying the transmission pulse generated by the transmission pulse generator and transmitting it as a radar wave via an antenna;
A pulse radar for receiving a reflected radar wave from a target received via the antenna as a received signal, identifying a primary echo from the received received signal, and outputting this as target data In the device
The transmission pulse generator is energized to sequentially generate two sets of transmission pulse trains of one and the other as the pulses for the radar wave with different reference phase amounts and equal pulse repetition periods and pulse numbers. Provide a pulse phase setting unit to
In addition to the receiver, a pulse phase corrector that corrects the phase of the reception signal at the reception timing corresponding to the transmission pulse in a phase opposite to the initial phase set in the transmission pulse by the pulse phase setting unit,
The pulse phase corrector is provided with a secondary trip echo canceller for removing the secondary trip echo from the received signal and detecting the primary echo based on the phase of the received signal after the phase correction. A pulse radar device characterized by the above.

(Appendix 2) In the pulse radar device according to Appendix 1,
A target detector for detecting a target signal from the received signal is provided in a signal input unit of the secondary trip echo canceller, and an echo for the received signal corresponding to the one transmission pulse train is provided in the secondary trip echo canceller. A reception signal storage is provided to store data temporarily.
The secondary trip echo canceller is stored in the received signal memory at the input timing of the echo data for the received signal received corresponding to the other transmission pulse train to the secondary trip echo canceler. A function of receiving echo data of the one reflected reception signal is provided.

(Appendix 3) In the pulse radar device according to Appendix 2,
A pulse radar device characterized in that a pulse compressor for performing a compression process, which is a correlation process between the received signal and the transmission pulse waveform, is disposed between the receiver and the pulse phase corrector.

(Appendix 4) In the pulse radar device according to Appendix 3,
Between the pulse phase corrector and the target detector, the received signals for each of the one and the other transmitted pulse trains corrected by the pulse phase corrector are coherently integrated and converted into a single received signal. A pulse radar device comprising an integration processor.

(Supplementary note 5) In the pulse radar device according to supplementary note 4,
Equipped with a speed difference detector instead of the secondary trip echo canceller,
Signal superposition processing in which the speed difference detector superimposes each reception signal corresponding to two sets of transmission pulse trains having different reference phase amounts in the received reception signal in accordance with the transmission timing of the two sets of transmission pulse trains. A processing unit; and an echo order specifying unit that specifies the order of echoes based on the primary echo with respect to the speed difference between the plurality of echoes obtained by the function of the signal superposition processing unit. Pulse radar device.

(Appendix 6) In the pulse radar device according to Appendix 5,
In the output stage of the speed difference detector, the distance of the target object for the first-order echo and the other-order echo is calculated based on the reception time, and the other order for the distance of the other-order echo is calculated. A pulse radar apparatus comprising a distance corrector for correcting a distance of minutes and calculating a distance of a target applied to the primary echo.

(Appendix 7) In the pulse radar device described in Appendix 4,
The integration processor is equipped with a processing data storage for storing the processing data of the reception signal for each one of the transmission pulse trains output from the integration processor, instead of the reception signal storage,
Between the integration processor and the target detector, the processing data of the received signal for each one of the transmission pulse trains stored in the processing data storage unit and the other transmissions output from the integration processor Equipped with a non-coherent integration processing unit that adds the amplitude of the received signal processing data for each pulse train,
2. A pulse radar apparatus according to claim 1, wherein the secondary trip echo remover removes the secondary trip echo based on information on the processing data stored in the processing data storage.

(Supplementary note 8) A transmission pulse generator for generating a transmission pulse for radar waves, a transmitter for amplifying the transmission pulse generated by the transmission pulse generator and transmitting it as a radar wave via an antenna, and via the antenna And a receiver that captures the reflected radar wave from the received target as a received signal, and identifies a primary echo from the captured received signal and outputs it as target data. A detection method,
The pulse phase setting unit provided in the transmission pulse generator sequentially generates one and the other two sets of transmission pulse trains having different reference phase amounts and the same pulse repetition period and number of pulses as the pulses for the radar wave. Energizing the transmit pulse generator to
The pulse phase corrector provided in the receiver corrects the phase of the reception signal at the reception timing corresponding to the transmission pulse with a phase opposite to the initial phase set for the transmission pulse in the pulse phase setting unit,
Each step of removing the secondary trip echo from the received signal based on the phase of the received signal after the phase correction is performed, detecting the primary echo, and removing and detecting the primary echo is provided in the pulse phase corrector. A target detection method for a pulse radar apparatus, which is executed by a secondary trip echo canceller.

(Supplementary note 9) A transmission pulse generator that generates a transmission pulse for radar waves, a transmitter that amplifies the transmission pulse generated by the transmission pulse generator and transmits it as a radar wave via an antenna, and the antenna And a receiver that captures the reflected radar wave from the received target as a received signal, and identifies a primary echo from the captured received signal and outputs it as target data. A detection processing program,
A pulse phase setting function for energizing the transmission pulse generator so as to sequentially generate two sets of transmission pulse trains having different reference phase amounts and the same pulse repetition period and number of pulses as the pulses for the radar wave;
A pulse phase correction function for correcting the phase of the reception signal at the reception timing corresponding to the transmission pulse with a phase opposite to the initial phase set for the transmission pulse in the pulse phase setting unit;
A secondary trip echo cancellation function for removing the secondary trip echo from the received signal and detecting the primary echo based on the phase of the received signal after the phase correction is performed;
A target detection processing program for a pulse radar apparatus, characterized in that a computer is realized.

1, 2, 3 Pulse radar device 11 Pulse phase setting device (pulse phase setting unit)
DESCRIPTION OF SYMBOLS 12 Transmission pulse generator 13 Transmitter 14 Transmission / reception switch 15 Antenna 16 Receiver 17 Pulse compressor 18 Pulse phase corrector 19 Integration processor 20 Target detector 21 Memory (reception signal storage part)
22 Secondary trip echo canceller 31 Speed difference detector 32 Distance corrector 41 Memory (2)
42 Non-coherent integration processor

Claims (9)

A transmission pulse generator for generating transmission pulses for radar waves;
A transmitter for amplifying the transmission pulse generated by the transmission pulse generator and transmitting it as a radar wave via an antenna;
A pulse radar for receiving a reflected radar wave from a target received via the antenna as a received signal, identifying a primary echo from the received received signal, and outputting this as target data In the device
The transmission pulse generator is energized to sequentially generate two sets of transmission pulse trains of one and the other as the pulses for the radar wave with different reference phase amounts and equal pulse repetition periods and pulse numbers. Provide a pulse phase setting unit to
In addition to the receiver, a pulse phase corrector that corrects the phase of the reception signal at the reception timing corresponding to the transmission pulse in a phase opposite to the initial phase set in the transmission pulse by the pulse phase setting unit,
The pulse phase corrector is provided with a secondary trip echo canceller for removing the secondary trip echo from the received signal and detecting the primary echo based on the phase of the received signal after the phase correction. A pulse radar device characterized by the above. The pulse radar device according to claim 1, wherein
A target detector for detecting a target signal from the received signal is provided in a signal input unit of the secondary trip echo canceller, and an echo for the received signal corresponding to the one transmission pulse train is provided in the secondary trip echo canceller. A reception signal storage is provided to store data temporarily.
The secondary trip echo canceller is stored in the received signal memory at the input timing of the echo data for the received signal received corresponding to the other transmission pulse train to the secondary trip echo canceler. A pulse radar device having a function of receiving echo data of the one reflected reception signal. The pulse radar device according to claim 2, wherein
A pulse radar device characterized in that a pulse compressor for performing a compression process, which is a correlation process between the received signal and the transmission pulse waveform, is disposed between the receiver and the pulse phase corrector. In the pulse radar device according to claim 3,
Between the pulse phase corrector and the target detector, the received signals for each of the one and the other transmitted pulse trains corrected by the pulse phase corrector are coherently integrated and converted into a single received signal. A pulse radar device comprising an integration processor. The pulse radar device according to claim 4, wherein
Equipped with a speed difference detector instead of the secondary trip echo canceller,
Signal superposition processing in which the speed difference detector superimposes each reception signal corresponding to two sets of transmission pulse trains having different reference phase amounts in the received reception signal in accordance with the transmission timing of the two sets of transmission pulse trains. A processing unit; and an echo order specifying unit that specifies the order of echoes based on the primary echo with respect to the speed difference between the plurality of echoes obtained by the function of the signal superposition processing unit. Pulse radar device. The pulse radar device according to claim 5, wherein
In the output stage of the speed difference detector, the distance of the target object for the first-order echo and the other-order echo is calculated based on the reception time, and the other order for the distance of the other-order echo is calculated. A pulse radar apparatus comprising a distance corrector for correcting a distance of minutes and calculating a distance of a target applied to the primary echo. The pulse radar device according to claim 4, wherein
The integration processor is equipped with a processing data storage for storing the processing data of the reception signal for each one of the transmission pulse trains output from the integration processor, instead of the reception signal storage,
Between the integration processor and the target detector, the processing data of the received signal for each one of the transmission pulse trains stored in the processing data storage unit and the other transmissions output from the integration processor Equipped with a non-coherent integration processing unit that adds the amplitude of the received signal processing data for each pulse train,
2. A pulse radar apparatus according to claim 1, wherein the secondary trip echo remover removes the secondary trip echo based on information on the processing data stored in the processing data storage. A transmission pulse generator for generating a transmission pulse for radar wave, a transmitter for amplifying the transmission pulse generated by the transmission pulse generator and transmitting it as a radar wave via an antenna, and received via the antenna A target detection method for a pulse radar device, comprising: a receiver that captures a reflected radar wave from a target as a received signal; and a primary echo is identified from the captured received signal and is output as target data. And
The pulse phase setting unit provided in the transmission pulse generator sequentially generates one and the other two sets of transmission pulse trains having different reference phase amounts and the same pulse repetition period and number of pulses as the pulses for the radar wave. Energizing the transmit pulse generator to
The pulse phase corrector provided in the receiver corrects the phase of the reception signal at the reception timing corresponding to the transmission pulse with a phase opposite to the initial phase set for the transmission pulse in the pulse phase setting unit,
Each step of removing the secondary trip echo from the received signal based on the phase of the received signal after the phase correction is performed, detecting the primary echo, and removing and detecting the primary echo is provided in the pulse phase corrector. A target detection method for a pulse radar apparatus, which is executed by a secondary trip echo canceller. A transmission pulse generator for generating a transmission pulse for radar wave, a transmitter for amplifying the transmission pulse generated by the transmission pulse generator and transmitting it as a radar wave via an antenna, and received via the antenna A target detection processing program for a pulse radar device, comprising: a receiver that captures a reflected radar wave from a target as a received signal; and a primary echo is identified from the captured received signal and is output as target data. There,
A pulse phase setting function for energizing the transmission pulse generator so as to sequentially generate two sets of transmission pulse trains having different reference phase amounts and the same pulse repetition period and number of pulses as the pulses for the radar wave;
A pulse phase correction function for correcting the phase of the reception signal at the reception timing corresponding to the transmission pulse with a phase opposite to the initial phase set for the transmission pulse in the pulse phase setting unit;
A secondary trip echo cancellation function for removing the secondary trip echo from the received signal and detecting the primary echo based on the phase of the received signal after the phase correction is performed;
A target detection processing program for a pulse radar apparatus, characterized in that a computer is realized.

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