JP2010038832A - Pulse radar apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire a pulse radar apparatus for obtaining a relative distance to a target by using the small number of PRIs even if the number of the targets is large. <P>SOLUTION: The pulse radar apparatus includes: a PRI setting device 1: a transmitting/receiving section 100 for transmitting a pulse train B per a plurality of the PRIs in the direction of the target A, receiving a reflection signal C, and generating a received video signal per range bin; a multiple distance/speed map generator 17 for implementing a Fourier transform of a plurality of the received video signals in the same range bin per plurality of the PRIs, and generating a plurality of distance/speed maps; a target detector 18 for detecting the target in a plurality of the distance/speed maps generated per a plurality of the PRIs; an identical target determining device 19 for determining an identity between a plurality of the targets detected by the distance/speed maps of a plurality of the different PRIs by using speed information on a plurality of the targets; and a ranging device 20 for obtaining the relative distance of the same target by using PRI information and range bin information of the same target in the distance/speed map generated per PRI. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pulse radar device that measures a relative distance to a target using a plurality of PRIs (Pulse Repetition Intervals).

  Conventionally, a pulse radar device that measures a relative distance from a target using a plurality of PRIs is well known (for example, see Non-Patent Document 1).

M.M. Skolnik, “Radar Handbook Second Edition,” McGraw-Hill, 17.20-17.25.

In the conventional pulse radar apparatus, since it is necessary to use at least the number of PRIs (target number + 1) larger than the target number in order to measure the relative distance to the target, the necessary PRI increases as the target number increases. There was a problem that the number of people increased.
Further, when the number of PRIs increases, the time required for measuring the relative distance from the target becomes longer, and there is a problem that distance measurement cannot be performed correctly with respect to the moving target.

  The present invention has been made in order to solve the above-described problems, and a pulse radar device capable of obtaining a relative distance to a target using a small number of PRIs even when the number of targets is large. The purpose is to obtain.

  The pulse radar device according to the present invention has a PRI setter for setting a plurality of PRIs capable of measuring the relative speed of one or more targets to be assumed without ambiguity, and a pulse train at a predetermined time interval for each of the plurality of PRIs. A transmission / reception unit that transmits in the direction of the target, receives a reflected signal from the target and generates a plurality of received video signals for each range bin, and Fourier transforms the plurality of received video signals for the same range bin for each of the plurality of PRIs Thus, a multi-distance speed map generator that generates a plurality of distance-velocity maps, a target detector that detects a target for each of a plurality of distance-velocity maps generated for each of a plurality of PRIs, and a distance-velocity map for different PRIs. Same target determiner and same target determiner that determine the sameness among detected targets using speed information of multiple targets With the range bin information and PRI information distance rate map generated for each PRI for the determined same goal it is obtained by a range finder for determining the relative distance of the same target.

  According to the present invention, radio waves are transmitted in a time-sharing manner by a plurality of PRIs that can be measured without ambiguity in the assumed target speed, and the received signals for the transmission signals of each PRI are used for each PRI. A target is detected by generating a distance-velocity map, and by calculating the relative distance of the target using the consistency between the PRIs of the relative speed information of the target obtained from the distance-velocity map obtained for each PRI, a large number of targets are obtained. Even in the case of a target, the relative distance of each target can be obtained with a small PRI.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
1 is a block diagram showing a functional configuration of a pulse radar apparatus according to Embodiment 1 of the present invention.
In FIG. 1, the pulse radar apparatus includes a transmission / reception unit 100 facing the target A, a video signal storage memory 16, a multi-distance speed map generator 17, a target detector 18, a same target determination unit 19, and a measurement. A distance device 20 is provided.

  The transmission / reception unit 100 includes a PRI setting unit 1, a timing generator 2, a local oscillator 3, a reference intermediate frequency signal generator 4, frequency converters 5 and 6, a pulse modulator 7, a power amplifier 8, A transmission / reception switch 9, an antenna 10 for transmission / reception, an intermediate frequency amplifier 11, a distributor 12, a 90-degree hybrid 13, a phase detector 14a, 14b, and A / D converters 15a, 15b are provided. ing.

The PRI setter 1, the timing generator 2, the local oscillator 3, the reference intermediate frequency signal generator 4, the frequency converter 5, the pulse modulator 7, the power amplifier 8, the transmission / reception switch 9 and the antenna 10 constitute a transmission unit. ing.
Also, a PRI setting device 1, a timing generator 2, a local oscillator 3, a reference intermediate frequency signal generator 4, a frequency converter 6, a transmission / reception switch 9, an antenna 10, an intermediate frequency amplifier 11, a distributor 12, a 90 degree hybrid device 13, the phase detectors 14a and 14b and the A / D converters 15a and 15b constitute a receiving unit.

  The PRI setting unit 1 sets a plurality of PRIs (pulse repetition periods) that can measure the relative speed of one or more target A without any ambiguity at predetermined time intervals.

  The transmission / reception unit 100 transmits the pulse train B in the direction of the target A at predetermined time intervals for each of the plurality of PRIs, receives the reflected signal C from the target A, and receives a plurality of received video signals for each range bin (described later). Digital video signals Di, Dq) are generated.

The video signal storage memory 16 stores the received video signal from the transmission / reception unit 100, and the multi-distance speed map generator 17 performs Fourier transform on the same range bin for each of the plurality of received video signals for each of the plurality of PRIs. , Generate multiple distance speed maps.
The target detector 18 detects a plurality of targets for each of a plurality of distance speed maps generated for each of a plurality of PRIs.

The same target determiner 19 functions as a speed matcher that determines the consistency of speed information, and the identity between a plurality of targets detected in the distance speed map for different PRIs is detected in each distance speed map. Determination is made using target speed information.
The distance measuring device 20 obtains the relative distance of the same target by using the range bin information and the PRI information of the distance / velocity map generated for each PRI for the same target determined to be the same by the same target determination unit 19.

Hereinafter, the function of each part of the first embodiment of the present invention shown in FIG. 1 will be described in more detail with reference to FIGS.
Here, PRI is expressed as T _pri1, and PRI (T _pri1 ) is set to 5 times the transmission pulse width T _p .

In the transmission / reception unit 100, the timing generator 2 generates a timing signal at an interval of PRI (T _pri1 ) from the PRI setting unit 1 and _inputs the timing signal to the pulse modulator 7 and the transmission / reception switch 9. The timing signal is used as a pulse modulation signal in the pulse modulator 7 and used as a transmission / reception switching signal in the transmission / reception switch 9.

The local oscillator 3 generates a local oscillation signal and inputs it to the frequency converters 5 and 6, and the reference intermediate frequency signal generator 4 generates a reference intermediate frequency signal and supplies it to the frequency converter 5 and the 90-degree hybrid unit 13. input.
The frequency converter 5 generates a transmission carrier signal having a frequency that is the sum of the frequency of the local oscillation signal from the local oscillator 3 and the frequency of the reference intermediate frequency signal from the reference intermediate frequency signal generator 5.

The pulse modulator 7 uses a timing signal (corresponding to a pulse modulation signal) from the timing generator 2 with respect to the transmission carrier signal from the frequency converter 5 and uses a predetermined pulse width for each pulse repetition period PRI1. subjected to a pulse modulation of T _p.
The power amplifier 8 takes in the output signal from the pulse modulator 7, amplifies the power, and inputs it to the transmission / reception switch 9.

The transmission / reception switch 9 transmits an input signal from the power amplifier 8 at a predetermined time interval for each PRI (T _pri1 ) in response to a timing signal (corresponding to a transmission / reception switching signal) from the timing generator 2. The signal is input to the antenna 10 as a trust signal.
The antenna 10 radiates the input signal from the transmission / reception switch 9 to space as a pulse train B (transmission signal).

The transmitted pulse train B is reflected to the target A and the background, and is received by the antenna 10 as a reflected signal C. The received signal (reflected signal C) from the antenna 10 is input to the transmission / reception switch 9.
In response to the timing signal from the timing generator 2 (corresponding to the transmission / reception switching signal), the reception switch 9 receives the reception signal input from the antenna 10 at a predetermined time interval for each PRI (T _pri ). Input to the frequency converter 6.

  The frequency converter 6 also receives a local oscillation signal from the local oscillator 3 for generating an intermediate frequency signal. The frequency converter 6 is a frequency of a difference between the frequency of the received signal and the frequency of the local oscillation signal. An intermediate frequency signal is generated and input to the intermediate frequency amplifier 11.

The intermediate frequency amplifier 11 amplifies the power of the intermediate frequency signal and inputs it to the distributor 12.
The distributor 12 distributes the intermediate frequency signal amplified by the intermediate frequency amplifier 11 into two, and individually inputs the signals to the phase detectors 14a and 14b.

  On the other hand, the 90-degree hybrid unit 13 separates the reference intermediate frequency signal from the reference intermediate frequency signal generator 5 into two signals having a phase difference of 90 degrees and inputs them individually to the phase detectors 14a and 14b. To do.

  The phase detectors 14a and 14b have a difference frequency between the frequency of the intermediate frequency signal and the frequency of the reference intermediate frequency signal from the input signal from the distributor 4b and the input signal from the 90-degree hybrid unit 13, and I component and Q component video signals I and Q having a phase difference of 90 degrees are generated.

The video signals I and Q generated by the phase detectors 14a and 14b are input to A / D converters 15a and 15b having a sampling frequency of 1 / T _p (corresponding to the reciprocal of the transmission pulse width T _p ).
A / D converter 15a, 15b, the video signal I, the Q, the digital video signal Di for each range bin of the same interval as the transmitted pulse width _{T p,} converted to Dq, the video signal storage memory 16 as a received video signal Remember.

  The video signal storage memory 16 stores a complex digital video signal in which the digital video signals Di of all the range bin numbers at the time intervals predetermined by the PRI setting unit 1 are real parts and the digital video signals Dq are imaginary parts.

Next, the PRI setter 1 is a PRI in which the relative speed of the target A to be assumed can be measured without ambiguity at a predetermined time interval, and the PRI setter 1 has a prime relationship with the PRI (T _pri1 ). Is set to PRI. Here, the new PRI is represented as T _pri2, and PRI (T _pri2 ) is set to four times the transmission pulse width T _p .
Thereafter, the above-described operation by the timing generator 2 to the video signal storage memory 16 is repeatedly executed with PRI as T _pri2 .

FIG. 2 is an explanatory diagram showing the PRI set by the PRI setting device 1, and shows the relationship between the range bin and the true range bin when the PRI is set to T _pri1 and T _pri2 .
In FIG. 2, a true range bin (0, 1, 2,..., 20) indicating a relative distance from the true target A and PRI is set to T _pri1 (5 times the transmission pulse width T _p ). _Shows the relationship between the range bin (0, 1, 2, 3, 4) and the range bin (0, 1, 2, 3) when PRI is set to T _pri2 (4 times the transmission pulse width T _p ). ing.

As apparent from FIG. 2, when PRI (T _pri1 ) is set to 5 times the transmission pulse width T _p and PRI (T _pri2 ) is set to 4 times the transmission pulse width T _p , the transmission pulse width up to 20 times the distance of T _p, it is possible to measure the relative distance unambiguously goal.

Hereinafter, the multi-distance speed map generator 17 uses the complex digital video signal of the same range bin number at the time of transmission with T _pri1 from the storage data (complex digital video signal) in the video signal storage memory 16 for each range bin. A distance-velocity map is generated by performing a Fourier transform and obtaining the resulting amplitude.

The multi-distance speed map generator 17 generates a distance speed map by _performing Fourier transform for each range bin using the complex digital video signal of the same range bin number at the time of transmission at T _pri2 and _obtaining the amplitude of the result. To do.

FIG. 3 is an explanatory diagram illustrating an example of a distance / velocity map, where the horizontal direction indicates a range bin and the vertical direction indicates a velocity bin.
FIG. 3A is a distance-velocity map when T _pri1 is _set to 5 times the transmission pulse width T _p , and shows a case where 16-point FFT (Fast Fourier Transform) is used as Fourier transform.
FIG. 3B is a distance-velocity map when T _pri2 is four times the transmission pulse width T _p , and shows a case where 16-point FFT is similarly used as Fourier transform.

In FIG. 3A, since T _pri1 is _set to 5 times the transmission pulse width T _p , the distance speed map for T _pri1 includes five range bins (0, 1, 2, 3, 4) and 16 And velocity bins (0, 1,..., 15).
On the other hand, in FIG. 3B, since T _pri2 is _set to four times the transmission pulse width T _p , the distance / velocity map for T _pri2 includes four range bins (0, 1, 2, 3) and 16 speeds. And bins (0, 1,..., 15).

The target detector 18 uses a CFAR (Constant False Alarm Rate) for each of the distance velocity map for T _pri1 shown in FIG. 3A and the distance velocity map for T _pri2 shown in FIG. The target A is detected.

FIG. 4 is an explanatory view showing the relative speeds of the speed bin numbers related to the plurality of targets A1, A2, and A3 and the true range bins in association with the explanatory diagram of FIG.
In addition, FIG. 5 specifically describes the targets detected in each range bin in relation to the targets A1 to A3 in FIG. 4 with respect to the distance / velocity maps of FIGS. 3 (a) and 3 (b). It is explanatory drawing.

  In FIG. 4, there is a target A1 having a relative speed of the speed bin number “7” at the relative distance of the true range bin number “2”, and a speed bin number “3” at the relative distance of the true range bin number “7”. ”And a target A3 having a relative speed of speed bin number“ 14 ”at a relative distance of true range bin number“ 9 ”.

In FIG. 5, in the distance / velocity map for T _pri1 , two targets (T1_1) and (T1_2) are detected for the range bin number “2”, and one target (T1_3) is detected for the range bin number “4”.
On the other hand, on the distance / velocity map for T _pri2 , one target (T2_1) is detected for the range bin number “1”, one target (T2_2) is detected for the range bin number “2”, and 1 for the range bin number “3”. One target (T2_3) is detected.

Same target determinator 19 determines in FIG. 5, with respect to the target detected in the distance velocity map for the distance rate map and T _PRI2 for T _Prit1, the target of the same speed bottle the same goal.
In the example of FIG. 5, (T1_1) and (T2_3) that are the same at the speed bin number “3” are determined to be the same target, and (T1_2) and (T2_2) that are the same at the speed bin number “7”. It is determined that they are the same target, and (T1_3) and (T2_1) that are the same for the speed bin number “14” are determined as the same target.

The range finder 20 uses the range bin information of the target of the distance speed map for T _pri1 and the distance speed map for T _pri2 determined as the same target by the same target determination unit 19, and uses the following range (1) to (1) to ( by 5) to determine the true range bin number N _t in the presence of the target where it is determined that the same target.

However, mod (X, Y) in the formulas (1), (4), and (5) indicates the remainder when X is divided by Y.
In Formula (1), N _pri1 indicates the range bin number on the distance speed map (FIG. 5) for the target T _pri1 determined as the same target by the same target determiner 19, and N _pri12 indicates the same target determination. The range bin number on the distance / velocity map for the target T _pri2 determined to be the same target by the device 19 is shown.
Furthermore, the coefficients K ₁ and K ₂ in the expressions (2) to (5) indicate the minimum natural numbers (positive integers) that satisfy the expressions (4) and (5), and _{depend on} the values of T _pri1 and T _pri2 . This is a value that can be obtained in advance.

For example, taking the detection targets (T1_1) and (T2_3) in FIG. 5 as an example, the range bin numbers N _pri1 and N _pri2 are N _pri1 = 2 and N _pri2 = 3.
As described above, since T _pri1 = 5T _p and T _pri2 = 4T _p , the coefficients K ₁ and K ₂ are K ₁ = 4 and K ₂ = 1.

Substituting the above values into the formulas (1) to (3) to obtain the true range bin number N _t where the target exists, N _t = 7, and the true range number where the target exists can be obtained correctly. .
Finally, the distance measuring device 20 obtains the relative distance of the same target by using the range bin information and the PRI information of the distance / velocity map generated for each PRI for the same target determined to be the same by the same target determination unit 19. .

  As described above, the pulse radar apparatus (FIG. 1) according to the first embodiment of the present invention uses a plurality of PRIs that can measure the relative speed of one or more target A without any ambiguity. For each PRI setter 1 to be set and a plurality of PRIs, a pulse train B is transmitted in the direction of the target A at a predetermined time interval, a reflected signal C from the target A is received, and a plurality of received video signals for each range bin A transmitter / receiver 100 that generates (digital video signals Di, Dq) and a plurality of distance velocity maps (FIG. 5) are generated by Fourier transforming a plurality of received video signals for each same range bin for each of a plurality of PRIs. A multi-distance speed map generator 17, a target detector 18 that detects a target A for each of a plurality of distance speed maps generated for each of a plurality of PRIs, and a different PRI PRI for the same target determined by the same target determiner 19 and the same target determined by the same target determiner 19 for determining the identity between the plurality of targets detected in the separation speed map. A range finder 20 for obtaining the relative distance of the same target using the range bin information and the PRI information of the distance speed map generated every time is provided.

Specifically, as shown in FIG. 5, the same target determination unit 19 determines a target having the same relative speed as a same target among a plurality of targets detected by distance speed maps for different PRIs.
As a result, even when there are a plurality of targets, it is possible to determine the identity of the target detected for each PRI using the relative speed information of the target A. Can be obtained.
Although not shown here, the same effects can be obtained even when pulse compression that modulates within a pulse is used together. Further, the obtained relative distance to the target A can be measured with higher resolution and higher accuracy by using pulse compression or synthetic band processing.

Embodiment 2. FIG.
In the first embodiment (FIGS. 1 to 5), targets having the same relative speed among a plurality of targets detected in the distance / velocity map for different PRIs are determined to be the same target, but as shown in FIG. In addition, a target having the closest relative speed among a plurality of targets detected in the distance speed map for different PRIs may be determined as the same target.

Hereinafter, the processing operation of the same target determination unit 19 according to the second embodiment of the present invention will be described with reference to FIG.
The configuration of the second embodiment of the present invention is as shown in FIG. 1, and only the partial operation of the same target determination unit 19 is different.

6, the same target determinator 19, with respect to the target detected by the distance velocity map for the distance rate map and T _PRI2 for T _PRI1, determines target closest relative speed equal target.

In the example of FIG. 6, the target (T1_1) with the speed bin number “3” and the target (T2_3) with the speed bin number “2” are determined as the same target, and the target (T1_2) with the speed bin number “7” and the speed The target (T2_2) with the bin number “8” is determined as the same target, and the target (T1_3) with the speed bin number “14” and the target (T2_1) with the speed bin number “15” are determined as the same target.
The processing of the transmitter / receiver 100, the video signal storage memory 16 to the target detector 18 and the distance measuring device 20 is the same as that of the first embodiment.

As described above, the same target determination unit 19 according to the second embodiment of the present invention determines a target having the closest relative speed among the plurality of targets detected by the distance speed map for different PRIs as the same target. Therefore, as described above, even when there are a plurality of targets, it is possible to determine the identity of the target detected for each PRI using the relative speed information of the target A. The relative distance to A can be obtained.
Furthermore, it is possible to cope with the case where the relative speeds of the targets detected for each PRI are different.
Although not shown here, the same effects can be obtained even when pulse compression that modulates within a pulse is used together. Further, the obtained relative distance to the target A can be measured with higher resolution and higher accuracy by using pulse compression or synthetic band processing.

Embodiment 3 FIG.
In the first embodiment (FIGS. 1 to 5), targets having the same relative speed among a plurality of targets detected by the distance / velocity map for different PRIs are determined to be the same target, but as shown in FIG. In addition, a target having the same relative speed and the closest strength among a plurality of targets detected in the distance / velocity map for different PRIs may be determined as the same target.

Hereinafter, the processing operation of the same target determination unit 19 according to Embodiment 3 of the present invention will be described with reference to FIG.
The configuration of the third embodiment of the present invention is as shown in FIG. 1, and only the partial operation of the same target determination unit 19 is different.

In FIG. 7, the size of the black circle indicates the target intensity.
In this case, the same target determinator 19, with respect to the target detected by the distance velocity map for the distance rate map and T _PRI2 for T _PRI1, the relative velocity is the same and the intensity is determined that the same target closest target .

In the example of FIG. _7, two goals in distance speed map speed bin number "3" for _{T pri1 (T1_1), (T1_3} ) is _present, the distance velocity map for the _{T PRI2} speed bin number "3" of the two Targets (T2_1) and (T2_3) exist.
Further, in the speed bin number “3”, the intensity of each target is approximated between (T1_1) and (T2_3) and approximated between (T1_3) and (T2_1).

Therefore, the targets (T1_1) and (T2_3) having the same speed bin number “3” and having similar intensities are determined as the same target, and the targets (T1_3) and (T2_1) are determined as the same target.
Furthermore, it is determined that the same target (T1_2) and (T2_2) with the same speed bin number “7” are the same target.

As described above, the same target determination unit 19 according to the third embodiment of the present invention has the same relative speed and the closest intensity among a plurality of targets detected by the distance speed maps for different PRIs. As described above, even when there are a plurality of targets, it is possible to determine the identity of the targets detected for each PRI using the relative speed information of the target A. The relative distance to the target A can be obtained using PRI.
Furthermore, it is possible to cope with a case where a plurality of targets exist in the same speed bin.
Although not shown here, the same effects can be obtained even when pulse compression that modulates within a pulse is used together. Further, the obtained relative distance to the target A can be measured with higher resolution and higher accuracy by using pulse compression or synthetic band processing.

Embodiment 4 FIG.
In the third embodiment (FIG. 7), the targets having the same relative speed and the closest strength among the plurality of targets detected in the distance / velocity map for different PRIs are determined as the same target. As shown in FIG. 8, a target having the closest relative speed and the closest strength among a plurality of targets detected in the distance speed map for different PRIs may be determined as the same target.

Hereinafter, the processing operation of the same target determination unit 19 according to the fourth embodiment of the present invention will be described with reference to FIG.
The configuration of the fourth embodiment of the present invention is as shown in FIG. 1, and only the partial operation of the same target determination unit 19 is different.

In FIG. 8, similarly to the above (FIG. 7), the size of the black circle indicates the target intensity.
In this case, the same target determinator 19, with respect to the target detected by the distance velocity map for the distance rate map and T _PRI2 for T _PRI1, determines close relative speed is highest, and the intensity is the closest target the same target .

In the example of FIG. _8, the target distance speed map speed bin number "3" with respect to _{T pri1 (T1_1),} the target (T2_3) distance speed map speed bin number "2" to _{T PRI2,} but relative speed to each other Is the closest and the intensity is the closest, so it is determined that they are the same target.
_Similarly, the target distance speed map speed bin number "3" with respect to _{T pri1 (T1_3),} the target distance speed map speed bin number "2" to _{T pri2} (T2_1) and is, it is determined that the same target .
_Further, the target distance speed map speed bin number "7" for _{T pri1 (T1_2),} the target distance speed map speed bin number "8" for _{T pri2} (T2_2), but it is determined that the same target.

As described above, the same target determination unit 19 according to the fourth embodiment of the present invention has the closest relative speed and the closest intensity among the plurality of targets detected by the distance speed maps for different PRIs. As described above, even if there are a plurality of targets, it is possible to take the sameness of the targets detected for each PRI using the relative speed information of the target A, and to reduce the plurality of PRIs. The relative distance to the target can be obtained using.
Furthermore, it is possible to cope with a plurality of targets having close relative speeds.
Although not shown here, the same effects can be obtained even when pulse compression that modulates within a pulse is used together. Further, the obtained relative distance to the target A can be measured with higher resolution and higher accuracy by using pulse compression or synthetic band processing.

Embodiment 5 FIG.
In the first to fourth embodiments (FIGS. 1 to 8), the re-determination process according to the distance measurement result of the distance measuring device 20 is not mentioned. However, as shown in FIG. The same target re-determination unit 21 responding to the distance measurement results is provided, and the distance measurement results of the distance measurement device 20 for all of the plurality of targets detected in the distance speed map for different PRIs are obtained from the plurality of PRIs. When the distance does not match the possible distance, the determination process of the identity between the plurality of targets may be executed again based on a determination criterion different from the previous one.

Hereinafter, the operation of the pulse radar device according to the fifth embodiment of the present invention will be described with reference to FIG. 10 and FIG.
In FIG. 9, the transmission / reception unit 100 and the video signal storage memory 16 to the distance measuring device 20 are the same as those described above (see FIG. 1), and are different from the above in that the same target re-determination unit 21 is added.

In this case, PRI setter 1 (5-fold T _p, 4-fold) above in addition to the PRI of at predetermined time intervals, which can measure the relative speed of the target A to be assumed ambiguities without a PRI, and _{T PRI1,} three times the PRI of the transmitted pulse width _{T p} which is a relatively prime to _{T PRI2,} newly set as _{T PRI3.}
10 in addition to the range bin in the case of the PRI and _{T PRI1, T PRI2,} range bins when the PRI and _{T PRI3} (0, 1, 2) and the true range bin (0,1, ..., 43, ...) is an explanatory diagram showing the relationship with.

As shown in FIG. 10, up to 60 times the distance of the transmission pulse width T _p, it is possible to measure the relative distance unambiguously goal. However, in order to simplify the drawing, FIG. 10, only it is abbreviated to 43 times the transmission pulse width T _p.

FIG. 11 is an explanatory diagram showing the operation of the same target re-determination unit 21, and FIGS. 12 (a) to 12 (d) are explanatory diagrams showing the same target possibilities Case1 to Case4.
11, two target velocity bin number "3" _is the distance velocity map for the _{T PRI1,} is detected as a range bin number "3" (point arrives) and range bin number "4" _{(T1_2),} for _{T PRI2} On the distance / velocity map, (T2_1) of the range bin number “1” and (T2_2) of the range bin number “2” are detected, and (T3_1) of the range bin number “1” on the distance / velocity map for T _pri3 . The range bin number “2” is detected as (T3_2).

In this case, there are four possibilities Case 1 to Case 4 shown in FIGS. 12A to 12D as the possibility of the same target. Among them, the combination indicating the true range bin number shown in FIG. Only one possibility Case1.
That is, the _targets of the range bin numbers “3”, “1”, “1” (true range bin number “13”) are determined to be the same target on the distance / velocity map for T _pri1 , T _pri2 , T _pri3 , and T _pri1 , The _targets of the range bin numbers “4”, “2”, “2” (true range bin number “14”) are determined to be the same target on the distance / velocity map for T _pri2 and T _pri3 .

  Therefore, once the same target determiner 19 determines that the combination of the second possibility Case2 is, for example, the same target redeterminer 21 indicates a distance where no true range bin number exists, all The identity determination process is repeatedly executed until a combination having a true range bin number with respect to the target (a combination of the first possibility Case 1 in the examples of FIGS. 11 and 12) is obtained.

As described above, the pulse radar device according to the fifth embodiment (FIG. 8) of the present invention includes the same target redetermining device 21 that responds to the distance measurement result of the distance measuring device 20.
The same target re-determination unit 21 confirms that the distance measurement results of the distance measuring device 20 for all of the plurality of targets detected in the distance / velocity map for different PRIs match the distances that can be measured from the plurality of PRIs. If it does not coincide, the determination process of the identity between the plurality of targets is executed again based on a determination criterion different from the previous one.

Thus, as described above, even when there are a plurality of targets, it is possible to take the same target detected for each PRI using the target relative speed information, and to reach the target using a small number of PRIs. The relative distance can be obtained.
Furthermore, it is possible to cope with a case where a plurality of targets having the same intensity exist in the same speed bin.
Although not shown here, the same effects can be obtained even when pulse compression that modulates within a pulse is used together. Further, the obtained relative distance to the target A can be measured with higher resolution and higher accuracy by using pulse compression or synthetic band processing.

It is a block diagram which shows the pulse radar apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows operation | movement of the PRI setting device in FIG. It is explanatory drawing which shows operation | movement of the multiple distance speed map generator in FIG. It is explanatory drawing which shows operation | movement of the target detector in FIG. It is explanatory drawing which shows operation | movement of the same target determination device in FIG. It is explanatory drawing which shows operation | movement of the same target determination device which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows operation | movement of the same target determination device which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows operation | movement of the same target determination device which concerns on Embodiment 4 of this invention. It is a block diagram which shows the pulse radar apparatus which concerns on Embodiment 5 of this invention. It is explanatory drawing which shows operation | movement of the PRI setting device in FIG. It is explanatory drawing which shows operation | movement of the target detector in FIG. It is explanatory drawing which shows operation | movement of the same target redeterminator in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 PRI setting device, 16 Video signal storage memory, 17 Multiple distance speed map generator, 18 Target detector, 19 Same target judgment device, 20 Distance measuring device, 21 Same target redeterminator, 100 Transmission / reception part, A target, B Pulse train, C Reflected signal, Di, Dq Digital video signal (received video signal).

Claims (6)

A PRI setting device for setting a plurality of PRIs (Pulse Repetition Intervals) that can measure the relative speed of one or more targets to be assumed without ambiguity;
For each of the plurality of PRIs, a transmission / reception unit that transmits a pulse train in a target direction at a predetermined time interval, receives a reflected signal from the target, and generates a plurality of received video signals for each range bin;
For each of the plurality of PRIs, a multi-distance speed map generator that generates a plurality of distance speed maps by Fourier transforming the plurality of received video signals for each same range bin;
A target detector for detecting the target for each of the plurality of distance-velocity maps generated for each of the plurality of PRIs;
The same target determiner for determining the identity between a plurality of targets detected in the distance speed map for different PRIs using the speed information of the plurality of targets;
A range finder for obtaining a relative distance of the same target using range bin information and PRI information of a distance speed map generated for each PRI for the same target determined to be the same by the same target determiner; A pulse radar device characterized by that.   2. The pulse radar according to claim 1, wherein the same target determination unit determines a target having the same relative speed as the same target among the plurality of targets detected by the distance-speed map for different PRIs. apparatus.   2. The pulse according to claim 1, wherein the same target determination unit determines a target having the closest relative speed among the plurality of targets detected in the distance speed map for different PRIs as the same target. Radar device.   The same target determination unit determines a target having the same relative speed and the closest strength as the same target among the plurality of targets detected by the distance-speed map for different PRIs. Item 2. The pulse radar device according to Item 1.   The same target determination unit determines a target having the closest relative speed and the closest strength among the plurality of targets detected in the distance speed map for different PRIs as the same target. Item 2. The pulse radar device according to Item 1. The same target re-determination unit responding to the distance measurement result of the distance measuring device,
In the same target re-determination unit, the range finding results of the range finder for all of the plurality of targets detected in the distance / velocity map for different PRIs coincide with the distances that can be obtained from the plurality of PRIs. 6. The identity determination process between the plurality of targets is executed again according to a determination criterion different from the previous one if the two do not coincide with each other. The pulse radar device according to any one of the above.

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