JP2011043476A - Pulse radar apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a pulse radar apparatus that can suppress clutters and high-order echoes, measures a relative speed by synthetic band processing with precise and high-speed resolution, and measures a distance with long-distance resolution. <P>SOLUTION: The pulse radar apparatus includes: a variable frequency oscillator 1 for outputting a signal train of an optional pattern, where a difference between adjacent frequencies becomes an integer multiple of a prescribed frequency when aligned in the order of frequency without any frequency overlapping, at a prescribed period; transmission means 2, 3a, 4 for generating and pulsing a transmission carrier signal from the signal train and a reference intermediate frequency signal to transmit a transmission signal; reception means 3b, 7-13 for generating a reflection signal from a target, or the like by the transmission signal and a reception video signal from the signal train and for cutting off frequency components other than the reflection signal; a relative speed measuring instrument 14 for obtaining relative speed of a target from the reception video signal; a relative speed correction synthetic band processor 15 for performing relative speed correction to the reception video signal according to the relative speed to perform synthetic band processing; and an envelope detector 16 for obtaining high-resolution distance measurement results of the target by synthetic band processing from the amplitude value of the output. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  This invention measures the relative velocity of the target from the reflected wave from the target for target tracking, etc., further performs synthetic band processing to measure the distance with high range resolution, and suppresses clutter and multi-order echoes. The present invention relates to a pulse radar device to be performed.

  In a radar apparatus that performs synthetic band processing, for example, the following Non-Patent Document 1 and Non-Patent Document 2 are methods for measuring a target relative velocity. In this device, transmission frequencies are transmitted in ascending order and descending order at a certain step interval, complex conjugate multiplication is performed on the received complex video signals in ascending order, and a relative speed is obtained by frequency analysis means such as IFFT (Inverse Fast Fourier Transform). . There is also a method of performing complex multiplication on the received complex video signals in ascending order and descending order and obtaining the relative speed by frequency analysis means such as FFT. The following non-patent document 3 is a prior art document related to the synthesis band method. However, this method does not describe how to deal with unnecessary signals such as clutter and multi-order echoes. In radar technology, there is MTI (Moving Target Indicator) as a clutter countermeasure technology, which is disclosed in Non-Patent Document 4 below. Further, as a multi-order echo suppression method using the synthesis band method, there is one described in Patent Document 1 below.

JP 2007-212245 A

Wang Fei, Long Teng, “A New Method of Velocity Estimation for Inverse V-Shape Stepped Frequency Signal”, CIE International Conference on Radar, Oct. 2006 Yuan Haotian, Cheng Zhen, Wen Shuliang, Peng Jun, “Study on radar target imaging and velocity measurement simultaneously based on step frequency waveforms”, Synthetic Aperture Radar 2007, 1st Asian and Pacific Conference, Nov. 2007 Donald R. Wehner, “High-Resolution Radar”, Artech House, Second Edition, Chapter 5, “Synthetic High-Range-Resolution Radar”, 197-237, September 1994 Sekine Matsuo, "Radar signal processing technology" 6th edition, IEICE, P.161-162, published January 10, 2006

The conceptual diagram of the relative speed measuring method of a prior art is shown in FIG. 18, FIG. In both figures, the horizontal axis represents time, and the vertical axis represents transmission frequency. In the figure, one square in the time direction represents the pulse repetition period T _PRI , and one square on the transmission frequency axis represents the step frequency Δf. Also, black and white dots in the figure represent the transmission frequency at that time. In the figure, an asterisk (*) indicates that complex conjugate is taken, and x indicates complex multiplication. FIG. 18 shows relative speed measurement using received video signals transmitted in ascending order and ascending order (prior art 1), and FIG. 19 shows relative speed using received video signals transmitted in ascending order and descending order (prior art 2). Represents a measurement. At this time, the total observation time used for relative velocity measurement is 2N _SBR T _PRI . At this time, the number of combined bands is N _SBR and the entire transmission band is N _SBR Δf.

The prior art will be briefly described below using mathematical expressions. First, relative speed measurement (prior art 2) using ascending and descending sequences as shown in FIG. 19 will be described. When the target is moving at a distance r and a relative speed v _d when the time t = 0, the transmission frequency is transmitted in an ascending sequence, and the received video signal of the reflected wave from the target is f _n = f ₀ + Δfn, It is expressed by the following formula as t = nT _PRI . Where f ₀ is the minimum transmission frequency, n is the number of pulses, n = 0, 1,..., N _SBR -1, c is the speed of light. However, in all of the following, for simplification of description, the window function based on the pulse signal waveform is omitted.

Next, the transmission frequency is transmitted in a descending sequence, and the received video signal of the reflected wave from the target is expressed by the following equation in consideration of after time N _SBR T _PRI . Here, f ′ _n = f ₀ −Δfn + (N _SBR −1) Δf.

  The complex multiplication of the above equations (1) and (2) is expressed by the following equation.

Therefore, when the above equation (3) is subjected to frequency analysis processing such as FFT, the target relative speed can be obtained by the following equation (4). However, k _P is when FFT equation (3), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

  Further, the relative speed, speed resolution, and maximum observation speed obtained by the relative speed measurement of the related art 1 using the ascending order and the ascending order or the descending order and the descending order sequence as shown in FIG.

  Since the conventional technique uses simple ascending and descending sequences, it has a drawback that a radar transmission signal can be easily detected by a target. In addition, because ascending and descending sequences are used, the frequency between adjacent transmission pulses is close, and if there is a large target at a distance greater than the maximum observation distance determined by the pulse repetition period, an unnecessary signal called a multi-order echo is generated. Received. When an unnecessary signal such as a multi-order echo is received in the received signal, it has a bad influence on the relative velocity measurement result, and has a drawback that a far target is erroneously measured as a short distance target.

Also. Since the observation time is 2N _SBR T _PRI , when this time transmission frequency is changed in ascending order, the maximum transmission band can be 2N _SBR Δf. However, in the conventional technology, since the signal of the same transmission frequency is transmitted twice, the entire transmission band is doubled, that is, the distance resolution is doubled with respect to the observation time (the efficiency is halved). Have

In addition, since the observation time is as long as 2N _SBR T _PRI , there is a disadvantage that in some cases it is not possible to cope with an agile target movement.

  Further, the relative velocity resolution is determined by the equation (5) or the equation (8), and there is a disadvantage that higher resolution and accuracy cannot be desired.

  In addition, when an unnecessary signal such as a static clutter is received as a received signal, there is a drawback that the relative speed measurement result is adversely affected.

  The present invention has been made to solve the above-described problems, and can suppress clutter and multi-order echoes. The relative speed can be measured with high accuracy and high speed resolution by synthetic band processing, and high distance resolution can be obtained. An object of the present invention is to provide a pulse radar device that performs the distance measurement.

  The present invention provides a signal sequence having frequencies corresponding to a frequency sequence of an arbitrary pattern in which the frequency difference is an integer multiple of a predetermined frequency interval when the frequencies are arranged in order of frequency without overlapping the frequencies. A variable frequency oscillator that outputs a signal with a predetermined pulse repetition period, a pulse signal obtained by pulsing a transmission carrier signal generated by a signal sequence from the variable frequency oscillator and a reference intermediate frequency signal, and transmission as a transmission signal And a reflected signal from the target and background obtained at each pulse repetition period by the transmission signal of the transmission means, a signal sequence from the variable frequency oscillator, and a reference intermediate frequency signal that is the same as the transmission signal Filter function for generating a video signal and blocking frequency components other than the frequency band of the reflected signal Including a receiving means, a relative speed measuring device for measuring the target relative speed from the received video signal, and a relative speed correction for the received video signal by a relative speed obtained by the relative speed measuring device to perform a combined band process. A relative velocity correction synthesis band processor to perform, an envelope detector for obtaining an amplitude value of the output of the relative speed correction synthesis band processor and outputting the target high-resolution ranging result by the synthesis band processing, The pulse radar apparatus is characterized by the above.

  According to the present invention, clutter and multi-order echo can be suppressed, and the relative speed can be measured with high accuracy and high speed resolution by synthetic band processing, and distance measurement with high distance resolution can be performed.

It is a figure which shows an example of a structure of the pulse radar apparatus by Embodiment 1-8 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 1 of this invention. It is a figure which shows another example of the frequency for every pulse repetition period in Embodiment 1 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 2 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 3 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 4 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 5 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 6 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 7 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 8 of this invention. It is a figure which shows an example of a structure of the pulse radar apparatus by Embodiment 9 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 9 of this invention. It is a figure for demonstrating operation | movement of the pulse radar apparatus by Embodiment 9 of this invention. It is a figure for demonstrating operation | movement of the pulse radar apparatus by Embodiment 9 of this invention. It is a figure which shows an example of a structure of the pulse radar apparatus by Embodiment 10 and 11 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 10 of this invention. It is a figure which shows an example of the frequency for every pulse repetition period in Embodiment 11 of this invention. It is a conceptual diagram for demonstrating the relative speed measuring method of a prior art. It is a conceptual diagram for demonstrating the relative speed measuring method of a prior art.

  Hereinafter, a pulse radar device according to the present invention will be described with reference to the drawings according to each embodiment. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
FIG. 1 is a diagram showing an example of the configuration of a pulse radar apparatus according to Embodiments 1 to 8 of the present invention. The variable frequency oscillator 1 sets a pulse repetition period T _PRI and repeatedly sets and oscillates the frequency of the composite band number _NSBR whose transmission frequency changes at an arbitrary frequency for each pulse repetition period. That is, a signal sequence having a frequency corresponding to such a frequency sequence is output at a predetermined pulse repetition period. However, when the frequencies oscillated for each pulse repetition period are arranged in ascending order, the frequency difference between adjacent frequencies is an integral multiple of the predetermined frequency interval Δf. FIG. 2 shows an example of the frequency (frequency sequence) for each pulse repetition period. The oscillated signal is sent to the frequency converters 3a and 3b.

  The reference intermediate frequency signal oscillator 2 oscillates a reference intermediate frequency signal and sends it to the frequency converter 3a and the 90-degree hybrid unit 10.

  The frequency converter 3 a generates a transmission carrier signal having the sum of the frequency of the signal oscillated by the variable frequency oscillator 1 and the frequency of the signal generated by the reference intermediate frequency signal oscillator 2, and sends the transmission carrier signal to the transmitter 4.

At transmitter 4, the signals from the frequency converter 3a pulsed at a predetermined pulse width T _P, and generates a pulse signal. The pulse signal is amplified by the transmitter 4 and sent to the transmission / reception switch 5. Hereinafter, the frequency sequence oscillated by the transmitter 4 is referred to as a transmission frequency sequence.

  The transmission / reception switch 5 switches the transmission / reception after transmitting a pulse signal from the antenna 6 as a transmission signal. The reflected signal from the target is received by the antenna 6 and then sent to the frequency converter 3b, where it is converted into an IF signal having a frequency difference between the frequency of the reflected signal and the frequency of the signal oscillated by the variable frequency oscillator 1, It is sent to the amplifier 7. The amplifier 7 amplifies the power of the IF signal, and the amplified signal is sent to the distributor 8.

  In the divider 8, the IF signal is divided into two signals and sent to the phase detectors 9a and 9b, respectively.

  On the other hand, the 90-degree hybrid 10 separates the reference intermediate frequency signal generated by the reference intermediate frequency signal oscillator 2 into two signals having a phase difference of 90 degrees, and outputs them to the phase detectors 9a and 9b. The phase detectors 9a and 9b have a frequency that is a difference between the frequency of the intermediate frequency signal and the frequency of the reference intermediate frequency signal from the input signal from the distributor 8 and the input signal from the 90-degree hybrid unit 10, and 90.degree. I component and Q component video signals (hereinafter referred to as I and Q video signals) having a phase difference of degrees are generated.

  The generated I and Q video signals are sent to the filter processors 11a and 11b to be filtered. An example of the filter is a matched filter that maximizes the signal-to-noise ratio (SNR). By the filter processing, echoes (multi-order echoes) farther than the maximum observation distance determined by the pulse repetition period are suppressed because they are converted by the frequency converter 3b into a frequency greatly different from the center frequency of the filter.

Filtered I, Q video signals, A / D converter 12a of the sampling frequency 1 / _{T P} (corresponding to the inverse of the transmit pulse width _{T P),} is input to 12b, the same interval as the transmission pulse width _{T P} Are converted into digital I and Q video signals for each range bin and stored in the video signal memory 13. The video signal memory 13 stores digital video signals as much as necessary for relative speed measurement and synthesis band processing. The digital I and Q video signals are hereinafter collectively referred to as a digital complex video signal (received video signal).

  In addition, the code | symbol 2, 3a, 4 part of FIG. 1 comprises a transmission means, and the code | symbols 3b and 7-13 comprise a receiving means.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

Assuming that the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n and the target is moving at a distance r and a relative speed v _d when the time t = 0, the digital complex video signal is It is represented by n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, in the variable frequency oscillator 1 oscillates by the time _{T S} shift 'transmission frequency sequence (frequency train) _{f n} satisfying _-f n = _{f S'} transmission frequency sequence (frequency train) _{f n} and _{f n.} However, f _S is a constant. An example of the transmission frequency sequence is shown in FIG. When a pulse signal is transmitted with the transmission frequency sequence f _n ′, the digital complex video signal is expressed by the following equation.

  Therefore, the complex conjugate multiplication of Expression (10) and Expression (11) is expressed by the following expression.

However, f _n ′ −f _n = f _S. Respect where f _n is n, how the transmission frequency is determined by the variable frequency oscillator 1 is known. Therefore, Equation (12) can be rearranged in ascending order of the oscillating frequency for each pulse repetition period. The digital complex video signal when Expression (12) is rearranged from the lowest frequency oscillated at each pulse repetition period is expressed by the following expression. However, the phases unrelated to n are collectively φ, and n ′ is rearranged in order of increasing frequency of oscillation in each pulse repetition period, so that n ′ overlaps between 0 and N _SBR −1. Almost random.

The phase in the first exp from the left in the equation (13) is not related to n, and the phase in the second exp from the left is almost random with no overlap between 0 and N _SBR −1. In IFFT, the second exp signal component from the left does not accumulate, and the third exp signal component from the left accumulates coherently (in-phase). Therefore, when the frequency analysis process such as IFFT is performed using Equation (13) The target relative speed can be obtained by the following formula. However, _{k P} is when IFFT equation (13), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

If you time shift _{T S} a _N SBR _{T PRI} description equivalent to the prior art, velocity resolution of formula (15) coincides with Equation (8). When f _S = 0, that is, f _n = f _n ′, the phase in the second exp from the left in Expression (13) is 0, and only the signal component of the third exp from the left in Expression (13) Pile up.

_Let v ^′ _d be the relative velocity obtained by equation (14). The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. The relative speed correction synthesis band processor 15 performs relative speed correction on the digital complex video signal based on the relative speed information from the relative speed measuring device 14 as in the following equation.

  Expression (17) and Expression (18) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and the synthesis band processing using frequency analysis processing such as IFFT is performed, and the target signal is detected by the envelope detector 16 (The amplitude value of the output of the relative velocity correction synthesis band processor 15 is obtained and the target high-resolution ranging result by the synthesis band process is outputted), and the tracking process is performed by the tracking processor 17 (envelope detector 16). The target is tracked from the distance value obtained from the above and the relative speed obtained by the relative speed measuring device 14).

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

As described above, by using the first embodiment, in the pulse radar apparatus that performs high-range resolution ranging by the synthetic band processing, the transmission signal of the radar is set as the target while maintaining the speed measurement performance equivalent to that of the conventional technique 1. Are difficult to detect, and the frequencies between transmission pulses are hardly close to each other, so that multi-order echoes can be suppressed. Further, when f _S = ΔfN _SBR and the total observation time is 2N _SBR T _PRI as shown in FIG. 3, the total transmission signal band obtained in this embodiment can be 2N _SBR Δf, which is a drawback of the conventional technique. It is possible to solve the problem that the distance resolution is doubled.

Embodiment 2. FIG.
The configuration of the pulse radar apparatus according to the second embodiment of the present invention is basically the same as that shown in FIG. However, in the first embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, different operations and processes will be described.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

Assuming that the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n and the target is moving at a distance r and a relative speed v _d when the time t = 0, the digital complex video signal is It is represented by n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, in the variable frequency oscillator 1 oscillates a 'transmission frequency sequence _{f n} satisfying = _{f S'} transmission frequency sequence _{f n} and _f n + _{f n} by the time _{T S} shift. However, f _S is a constant. An example of the transmission frequency sequence is shown in FIG. When a pulse signal is transmitted with the transmission frequency sequence f _n ′, the digital complex video signal is expressed by the following equation.

  Therefore, the complex multiplication of Expression (19) and Expression (20) is expressed by the following expression.

However, f _n + f _n ′ = f _S. Here, since f _n is an arbitrary frequency with respect to n, there is no overlap, and the fourth exp signal component from the left in Expression (21) is not accumulated by frequency analysis processing such as FFT. Therefore, when the frequency analysis process such as FFT is performed on the equation (21), the target relative speed can be obtained by the following equation. However, k _P is when FFT equation (21), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

Here, f _S is a condition equivalent to that described in the related art 2. In the case of 2f ₀ + (N _SBR −1) Δf, the speed resolution of the equation (23) is expressed by the following equation, and the speed resolution of the prior art 2 and the equation (5) is improved. Recognize.

The relative velocity obtained by the equation (22) is set as v ^′ _d . The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. The relative speed correction synthesis band processor 15 performs relative speed correction on the digital complex video signal based on the relative speed information from the relative speed measuring device 14 as in the following equation.

  Expression (26) and Expression (27) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and a synthesis band process using a frequency analysis process such as IFFT is performed, and a target signal is detected by the envelope detector 16. Then, the tracking processor 17 performs the tracking process.

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

As described above, by using the second embodiment, in the pulse radar that measures the distance with high distance resolution by the synthetic band processing, the transmission signal of the radar is set as the target while maintaining the speed measurement performance equal to or higher than that of the conventional technique 2. Are difficult to detect, and the frequencies between transmission pulses are hardly close to each other, so that multi-order echoes can be suppressed. Further, as shown in FIG. 4, when f _S = 2f ₀ + (2N _SBR −1) Δf and the total observation time is 2N _SBR T _PRI , the total transmission signal bandwidth obtained in this embodiment is 2N _SBR Δf. It is possible to solve the problem that the distance resolution, which is a disadvantage of the prior art, is doubled.

Embodiment 3 FIG.
The configuration of the pulse radar device according to the third embodiment of the present invention is basically the same as that shown in FIG. However, in the first embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, different operations and processes will be described.

In the variable frequency oscillator 1, the transmission frequency sequence output from the transmitter 4 is a pulse repetition of the transmission frequency sequence f _n and f _n ′ (where f _n ′ −f _n = f _S ) described in the first embodiment. It is set to alternate every period T _PRI . FIG. 5 shows an example of the frequency for each pulse repetition period. The oscillated signal is sent to the frequency converters 3a and 3b.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

When the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n and the target is moving at a distance r and a relative speed v _d when the time is t = 0, only the transmission frequency sequence f _n is obtained. When attention is paid, since the pulse repetition period is 2T _PRI , the digital complex video signal is expressed by the following equation. n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, in the variable frequency oscillator 1, _'when the transmission frequency sequence f _n' transmission frequency sequence f _n where attention is paid only, since the pulse repetition period is to become 2T _PRI, digital complex video signal by the following equation expressed.

However, in order to simplify the explanation, T _S = 0. Therefore, the complex conjugate multiplication of Expression (28) and Expression (29) is expressed by the following expression.

However, f _n ′ −f _n = f _S. Respect where f _n is n, because it is a duplicate without any frequency, the signal component of the third exp from the left of the formula (30) is not increased loading by the frequency analysis processing such as IFFT. Therefore, when the frequency analysis process such as IFFT is performed on the equation (30), the target relative speed can be obtained by the following equation. However, _{k P} is when IFFT equation (30), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

When f _S is ΔfN _SBR , the speed resolution of the equation (32) is equal to ½ of the equation (8). That is, the speed resolution is improved by a factor of 2 over the prior art 1.

The relative velocity obtained by the equation (31) is assumed as v ^′ _d . The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. The relative speed correction synthesis band processor 15 performs relative speed correction on the digital complex video signal based on the relative speed information from the relative speed measuring device 14 as in the following equation.

  Expression (34) and Expression (35) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and a synthetic band process using a frequency analysis process such as IFFT is performed, and the target signal is detected by the envelope detector 16. Then, the tracking processor 17 performs the tracking process.

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

As described above, by using the third embodiment, in a pulse radar apparatus that performs high-range resolution ranging by synthetic band processing, the transmission signal of the radar is transmitted to the target while maintaining the speed measurement performance higher than that of the prior art 1. It is difficult to detect and the frequencies between the transmission pulses are hardly close to each other, so that the multi-order echo can be suppressed. Further, when f _S = ΔfN _SBR and the total observation time is 2N _SBR T _PRI as shown in FIG. 5, the total transmission signal band obtained in this embodiment can be 2N _SBR Δf, which is a disadvantage of the prior art. It is possible to solve the problem that the distance resolution is doubled.

Embodiment 4 FIG.
The configuration of the pulse radar device according to the fourth embodiment of the present invention is basically the same as that shown in FIG. However, in the first embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, different operations and processes will be described.

In the variable frequency oscillator 1, the transmission frequency sequence output from the transmitter 4 uses the transmission frequency sequence f _n and f _n ′ (where f _n + f _n ′ = f _S ) described in the first embodiment as a pulse repetition period. Set to alternate every T _PRI . FIG. 6 shows an example of the frequency for each pulse repetition period. The oscillated signal is sent to the frequency converters 3a and 3b.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

When the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n and the target is moving at a distance r and a relative speed v _d when the time is t = 0, only the transmission frequency sequence f _n is obtained. When attention is paid, since the pulse repetition period is 2T _PRI , the digital complex video signal is expressed by the following equation. n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, in the variable frequency oscillator 1, _'when the transmission frequency sequence f _n' transmission frequency sequence f _n where attention is paid only, since the pulse repetition period is to become 2T _PRI, digital complex video signal by the following equation expressed.

However, in order to simplify the description, T _S = 0 is used hereinafter. Therefore, the complex multiplication of Expression (36) and Expression (37) is expressed by the following expression.

However, f _n + f _n ′ = f _S. Here, since f _n is an arbitrary frequency with respect to n, there is no overlap, and therefore, the third exp signal component from the left in equation (38) is not accumulated by frequency analysis processing such as FFT. Therefore, when the frequency analysis process such as FFT is performed on the equation (38), the target relative speed can be obtained by the following equation. However, k _P is when FFT equation (38), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

Here, f _S is the same condition as in the description of the prior art. In the case of 2f ₀ + (N _SBR −1) Δf, the speed resolution of the equation (40) is expressed by the following equation, and the speed resolution of the prior art 2 and the equation (5) is improved. Recognize.

The relative velocity obtained by the equation (39) is set as v ^′ _d . The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. The relative speed correction synthesis band processor 15 performs relative speed correction on the digital complex video signal based on the relative speed information from the relative speed measuring device 14 as in the following equation.

  Expression (43) and Expression (44) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and synthesis band processing using frequency analysis processing such as IFFT is performed, and the target signal is detected by the envelope detector 16 Then, the tracking processor 17 performs the tracking process.

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

As described above, by using the fourth embodiment, in the pulse radar device that performs high-range resolution ranging by the synthetic band processing, the transmission of the radar to the target is maintained while maintaining the speed measurement performance equal to or higher than that of the conventional technique 2. It is difficult to detect the signal, and the frequencies between the transmission pulses are hardly close to each other, so that the multi-order echo can be suppressed. Further, when f _S = 2f ₀ +2 (N _SBR −1) Δf and the total observation time is 2N _SBR T _PRI as shown in FIG. 6, the total transmission signal bandwidth obtained in this embodiment is 2N _SBR Δf. It is possible to solve the problem that the distance resolution, which is a disadvantage of the prior art, is doubled.

Embodiment 5 FIG.
The configuration of the pulse radar apparatus according to the fifth embodiment of the present invention is basically the same as that shown in FIG. However, in the first embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, different operations and processes will be described.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

Assuming that the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n = f ₀ + nΔf, when the target is moving at a distance r and a relative speed v _d when the time t = 0, digital complex video The signal is expressed by the following equation. n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, the variable frequency oscillator 1 oscillates by shifting the transmission frequency sequence f _n ′ = f _S + f ₀ + nΔf satisfying the transmission frequency sequences f _n and f _n ′ −f _n = f _S by time T _S. However, f _S is a constant. The transmission frequency sequence is shown in FIG. When a pulse signal is transmitted with the transmission frequency sequence f _n ′, the digital complex video signal is expressed by the following equation.

  Therefore, the complex conjugate multiplication of Expression (45) and Expression (46) is expressed by the following expression.

However, f _n ′ −f _n = f _S. The phase of the first exp and the second exp from the left in equation (47) is independent of n, and the third exp signal component from the left accumulates coherently (in-phase). When the frequency analysis process is performed, the target relative speed can be obtained by the following equation. However, _{k P} is when IFFT equation (47), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

The relative velocity obtained by the equation (48) is set as v ^′ _d . The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. The relative speed correction synthesis band processor 15 performs relative speed correction on the digital complex video signal based on the relative speed information from the relative speed measuring device 14 as in the following equation.

  Expression (51) and Expression (52) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and the synthesis band processing using frequency analysis processing such as IFFT is performed, and the target signal is detected by the envelope detector 16 Then, the tracking processor 17 performs the tracking process.

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

As described above, by using the fifth embodiment, in the pulse radar apparatus that performs ranging with high range resolution by the synthesis band processing, f _S = ΔfN _SBR as shown in FIG. 7, and the total observation time is 2N _SBR T _PRI. In this case, the total transmission signal band obtained in this embodiment can take 2N _SBR Δf, which can solve the problem that the distance resolution, which is a drawback of the prior art, is doubled. At this time, the speed resolution is c / (4ΔfT _PRI N ² _SBR ) according to the equation (49), and the speed resolution is improved as compared with the prior art 1.

Embodiment 6 FIG.
The configuration of the pulse radar device according to the sixth embodiment of the present invention is basically the same as that shown in FIG. However, in the first embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, different operations and processes will be described.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

Assuming that the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n = f ₀ + nΔf, when the target is moving at a distance r and a relative speed v _d when the time t = 0, digital complex video The signal is expressed by the following equation. n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, in the variable frequency oscillator 1 oscillates a 'transmission frequency sequence _{f n} satisfy _{= f S' = f S -f} 0 -nΔf transmission frequency sequence _{f n} and _f n + _{f n} time _{T S} is shifted. However, f _S is a constant. The transmission frequency sequence is shown in FIG. When a pulse signal is transmitted with the transmission frequency sequence f _n ′, the digital complex video signal is expressed by the following equation.

  Therefore, the complex multiplication of Expression (53) and Expression (54) is expressed by the following expression.

However, f _n + f _n ′ = f _S. The phase in the first and second exp from the left in the equation (55) is not related to n, and the signal components of the third exp from the left are accumulated coherently (in-phase). When the frequency analysis process is performed, the target relative speed can be obtained by the following equation. However, k _P is when FFT equation (55), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

The relative velocity obtained by the equation (56) is set as v ^′ _d . The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. Based on the relative velocity information from the relative velocity measuring device 14, the relative velocity correction synthesis band processor 15 performs relative velocity correction on the digital complex video signal as in the following equation.

  Equation (59) and Equation (60) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and the synthesis band processing using frequency analysis processing such as IFFT is performed, and the envelope detector 16 detects the target signal. Then, the tracking processor 17 performs the tracking process.

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

As described above, by using the sixth embodiment, in a pulse radar apparatus that performs high-range resolution ranging by synthetic band processing, f _S = 2f ₀ + (2N _SBR −1) Δf as shown in FIG. When the total observation time is 2N _SBR T _PRI , the total transmission signal band obtained in this embodiment can be 2N _SBR Δf, which can solve the problem that the distance resolution that is the disadvantage of the prior art is doubled. . At this time, the velocity resolution is consistent with Equation (5) from Equation (57), and the velocity measurement performance of Conventional Technology 2 is also maintained.

Embodiment 7 FIG.
The configuration of the pulse radar apparatus according to the seventh embodiment of the present invention is basically the same as that shown in FIG. However, in the first embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, different operations and processes will be described.

In the variable frequency oscillator 1, the transmission frequency sequence output from the transmitter 4 is a pulse repetition of the transmission frequency sequence f _n and f _n ′ (where f _n ′ −f _n = f _S ) described in the first embodiment. It is set to alternate every period T _PRI . FIG. 9 shows an example of the frequency for each pulse repetition period. The oscillated signal is sent to the frequency converters 3a and 3b. However, f _n = f ₀ + nΔf and f _n ′ = f _S + f ₀ + nΔf.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

When the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n and the target is moving at a distance r and a relative speed v _d when the time is t = 0, only the transmission frequency sequence f _n is obtained. When attention is paid, since the pulse repetition period is 2T _PRI , the digital complex video signal is expressed by the following equation. n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, in the variable frequency oscillator 1, _'when the transmission frequency sequence f _n' transmission frequency sequence f _n where attention is paid only, since the pulse repetition period is to become 2T _PRI, digital complex video signal by the following equation expressed.

However, in order to simplify the explanation, T _S = 0. Therefore, the complex conjugate multiplication of Equation (61) and Equation (62) is expressed by the following equation.

However, f _n ′ −f _n = f _S. The phase in the first and second exp from the left in the equation (63) is not related to n. Therefore, when the frequency analysis process such as IFFT is performed on the equation (63), the target relative speed can be obtained by the following equation. However, _{k P} is when IFFT equation (63), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

When f _S is ΔfN _SBR , the speed resolution of the equation (65) is almost equal to ½ of the equation (8). That is, the speed resolution is improved about twice as much as the prior art 1.

The relative velocity obtained by the formula (64) and v _^'d. The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. The relative speed correction synthesis band processor 15 performs relative speed correction on the digital complex video signal based on the relative speed information from the relative speed measuring device 14 as in the following equation.

  Expression (67) and Expression (68) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and synthesis band processing using frequency analysis processing such as IFFT is performed, and the target signal is detected by the envelope detector 16 Then, the tracking processor 17 performs the tracking process.

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

In this way, by using the seventh embodiment, in a pulse radar apparatus that performs high-range resolution ranging by synthetic band processing, the transmission signal of the radar is sent to the target while maintaining the speed measurement performance of the prior art 1 or higher. It is difficult to detect and the frequencies between the transmission pulses are hardly close to each other, so that the multi-order echo can be suppressed. Further, when f _S = ΔfN _SBR and the total observation time is 2N _SBR T _PRI as shown in FIG. 9, the total transmission signal band obtained in this embodiment can be 2N _SBR Δf, which is a disadvantage of the prior art. It is possible to solve the problem that the distance resolution is doubled.

Embodiment 8 FIG.
The configuration of the pulse radar apparatus according to the eighth embodiment of the present invention is basically the same as that shown in FIG. However, in the first embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, different operations and processes will be described.

In the variable frequency oscillator 1, the transmission frequency sequence output from the transmitter 4 uses the transmission frequency sequence f _n and f _n ′ (where f _n + f _n ′ = f _S ) described in the first embodiment as a pulse repetition period. Set to alternate every T _PRI . FIG. 10 shows an example of the frequency for each pulse repetition period. The oscillated signal is sent to the frequency converters 3a and 3b. However, f _n = f ₀ + nΔf and f _n ′ = f _S −f ₀ −nΔf.

  The relative speed measuring device 14 measures the target relative speed from the digital I and Q video signals. The measurement method will be described below using mathematical formulas.

When the transmission frequency sequence oscillated for each pulse by the transmitter 4 is f _n and the target is moving at a distance r and a relative speed v _d when the time is t = 0, only the transmission frequency sequence f _n is obtained. When attention is paid, since the pulse repetition period is 2T _PRI , the digital complex video signal is expressed by the following equation. n is the number of pulses, n = 0, 1,..., _NSBR- 1, c is the speed of light.

Further, in the variable frequency oscillator 1, _'when the transmission frequency sequence f _n' transmission frequency sequence f _n where attention is paid only, since the pulse repetition period is to become 2T _PRI, digital complex video signal by the following equation expressed.

However, in order to simplify the explanation, T _S = 0. Therefore, the complex multiplication of Expression (69) and Expression (70) is expressed by the following expression.

However, f _n + f _n ′ = f _S. The phase in the first and second exps from the left in the formula (71) is not related to n. Therefore, when the frequency analysis process such as FFT is performed on the equation (71), the target relative speed can be obtained by the following equation. However, k _P is when FFT equation (71), in that the amplitude becomes maximum.

  Therefore, the speed resolution is expressed by the following equation.

  The maximum observation speed is expressed by the following equation.

Here, f _S is the same condition as in the description of the prior art 2. When 2f ₀ + (N _SBR −1) Δf, the speed resolution of Expression (73) is expressed by the following expression, and it can be seen that the speed resolution is equal to or slightly improved as compared with the prior art.

The relative velocity obtained by the equation (72) is set as v ^′ _d . The obtained relative velocity information is sent to the relative velocity correction synthesis band processor 15 and the tracking processor 17. The relative speed correction synthesis band processor 15 performs relative speed correction on the digital complex video signal based on the relative speed information from the relative speed measuring device 14 as in the following equation.

  Expression (76) and Expression (77) are rearranged in order from the lowest frequency oscillated at each pulse repetition period, and the synthesis band processing using frequency analysis processing such as IFFT is performed, and the envelope detector 16 detects the target signal. Then, the tracking processor 17 performs the tracking process.

  As a detection process performed by the envelope detector 16, for example, a detection method based on CFAR (Constant False Alarm Rate) can be considered. The tracking process performed by the tracking processor 17 may be a tracking process using a Kalman filter, for example.

As described above, by using the eighth embodiment, in a pulse radar device that performs high-range resolution ranging by synthetic band processing, the radar transmission to the target is maintained while maintaining speed measurement performance equal to or higher than that of the conventional technique 2. It is difficult to detect the signal, and the frequencies between the transmission pulses are hardly close to each other, so that the multi-order echo can be suppressed. Further, as shown in FIG. 10, when f _S = 2f ₀ +2 (N _SBR −1) Δf and the total observation time is 2N _SBR T _PRI , the total transmission signal bandwidth obtained in this embodiment is 2N _SBR Δf. It is possible to solve the problem that the distance resolution, which is a disadvantage of the prior art, is doubled.

Embodiment 9 FIG.
FIG. 11 is a diagram showing an example of the configuration of a pulse radar apparatus according to Embodiment 9 of the present invention. The pulse radar apparatus of FIG. 11 has a configuration in which a relative velocity ambiguity resolution processor 18 is added to the configuration of the pulse radar apparatus of FIG. Further, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. The ninth embodiment will be described below with reference to FIG. In the description, the operations of the variable frequency oscillator 1 and the added relative speed ambiguity resolution processing unit 18 and the signal processing of the relative speed measuring unit 14 and the relative speed correction synthesis band processing unit 15 will be described. Other processes and operations are the same as those described in the first to eighth embodiments.

  In the variable frequency oscillator 1, the transmission frequency sequence of the transmitter 4 can be arbitrarily switched to the transmission frequency sequence described in the first to eighth embodiments (can be arbitrarily switched and sequentially selected). An example of the transmission frequency sequence is shown in FIG.

  In the transmission frequency sequence shown in FIG. 12, the transmission frequency sequence indicated by the black circle symbol and the white circle symbol in each of the sections 1, 2, 3, and 4 is the same as the transmission frequency sequence described in the eighth embodiment. It has become.

  Further, all combinations obtained by extracting two of the black circle symbols and white circle symbols in the sections 1, 2, 3, and 4 are the fifth embodiment, the sixth embodiment, the seventh embodiment, This is the transmission frequency sequence described in the eighth embodiment.

  Further, the transmission frequency sequence indicated by the black circle symbol and the white circle symbol in each of the sections 5 and 6 is the transmission frequency sequence described in the eighth embodiment.

  Further, all combinations obtained by extracting two of the transmission frequency sequences of the black circle symbol and the white circle symbol in the sections 5 and 6 will be described in the fifth embodiment, the sixth embodiment, the seventh embodiment, and the eighth embodiment. Transmission frequency sequence.

  In the relative velocity measuring device 14, the relative velocity measurement shown in the fifth embodiment, the sixth embodiment, the seventh embodiment, and the eighth embodiment according to the transmission frequency sequence of the transmitter 4 is performed at least twice, The speed measurement result is output to the relative speed ambiguity resolution processor 18.

The relative speed ambiguity resolution processor 18 resolves the ambiguity of the target relative speed. Here, the ambiguity means that when the target relative speed v _d is equal to or higher than the maximum observation speed v _{d, max} , the observed relative speed is observed as an integer multiple of v _d −v _{d, max.} . The conceptual diagram is shown in FIG. For example, it is assumed that the relative speed measurement device 14 performs relative speed measurement using the transmission frequency sequence of section 1 and the transmission frequency sequence of black circle symbols of sections 1 and 2 shown in FIG.

  When the relative speed measurement is performed in the transmission frequency sequence in section 1 in FIG. 12, as shown in the eighth embodiment, the speed resolution and the maximum observation speed are expressed by the following equations.

Further, when the relative speed measurement is performed with the transmission frequency sequences of the black circle symbols in section 1 and section 2 in FIG. 12, the transmission frequency sequence in which T _PRI is doubled and _NSBR is halved in the fifth embodiment, Considering, as shown in the fifth embodiment, the velocity resolution and the maximum observation velocity are expressed by the following equations.

  Comparing equation (78) and equation (80), the velocity resolution is smaller in equation (78) and the performance is better. However, comparing Equation (79) with Equation (81), the maximum observation speed is larger in Equation (81), and the relative speed of the high-speed target can be observed without ambiguity.

  The relative speed ambiguity resolution processor 18 uses the relative speed measurement result of the transmission frequency sequence with no ambiguity, as shown in FIG. 14 (a) with ambiguity and without (b) ambiguity, It is characterized by solving the ambiguity of the relative speed measurement result of the transmission frequency sequence with good resolution. Further, the relative speed ambiguity resolution processor 18 may resolve the ambiguity of the relative speed measurement result by using the speed information from another sensor or the relative speed obtained from another speed measurement method. The speed information of other sensors is, for example, the speed obtained by observation with a radar other than the radar apparatus of the present invention or a sensor other than the radar. Another speed measurement method is, for example, a relative speed obtained from a Doppler process or a time change of an observed distance value. The target relative velocity (in this case, the transmission frequency sequence of section 1) measured with the transmission frequency sequence with good velocity resolution in which the ambiguity has been resolved is output to the relative velocity measuring instrument 14 and is subjected to the relative velocity correction composite band. It is output to the processor 15.

The relative speed correction synthesis band processor 15 performs a relative speed correction on the digital complex video signal using the target relative speed whose ambiguity is resolved, and performs a synthesis band process using a frequency analysis process such as IFFT. And output to the envelope detector 16. At this time, an arbitrary digital complex video signal can be selected as long as a desired total transmission signal bandwidth and ΔfN _SBR can be secured as the digital complex video signal used for the synthesis band processing. For example, it is a digital complex video signal obtained in section 1 in FIG.

  As described above, by using the ninth embodiment, in the pulse radar device that performs high-range resolution ranging by the synthetic band processing, the speed measurement performance equal to or higher than that in the conventional technique is maintained with less observation time. However, it is difficult for the target to detect the transmission signal of the radar, and the frequency between the transmission pulses is hardly close, so that the multi-order echo can be suppressed. In addition, it is possible to solve the problem that the distance resolution, which is a disadvantage of the prior art, is doubled, and to solve the ambiguity of the relative speed result.

Embodiment 10 FIG.
FIG. 15 is a diagram showing an example of the configuration of the pulse radar apparatus according to Embodiments 10 and 11 of the present invention. The pulse radar apparatus of FIG. 15 has a configuration in which an MTI processor 19 is added to the configuration of the pulse radar apparatus of the ninth embodiment of FIG. Further, the operation of the variable frequency oscillator 1 is different from that of the ninth embodiment. Embodiment 10 will be described below with reference to FIG. 16 showing an example of a transmission frequency sequence in this embodiment. In the description, the operations of the variable frequency oscillator 1 and the added MTI processor 19 will be described. Other processes and operations are the same as those in the ninth embodiment.

In the variable frequency oscillator 1, the transmission frequency sequence of transmitter 4, can switch arbitrarily to the transmission frequency sequence described in the first to eighth embodiments, for example, the time shift T _S transmission frequency sequence as shown in Figure 16 It can be set to a transmission frequency sequence (selectable by switching arbitrarily, and repeatedly output after a predetermined time). For example, in Figure 16 the time shift _{T S} is _{2T PRI.}

  The MTI processor 19 performs MTI processing on the received digital complex video signal. The MTI processing is processing for transmitting a pulse signal at the same transmission frequency and taking the difference between the received digital complex video signals. Clutter (unnecessary signal) represented by a stationary target or the like is suppressed by MTI processing.

  The digital complex video signal subjected to MTI processing by the MTI processor 19 is output to the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15.

  As described above, by using the tenth embodiment, the pulse radar device that performs high-range resolution ranging by the synthetic band processing maintains the same or better speed measurement performance with less observation time than the conventional technology. However, it is difficult for the target to detect the transmission signal of the radar, and the frequency between the transmission pulses is hardly close, so that the multi-order echo can be suppressed. Further, clutter (unnecessary signal) typified by a stationary target or the like can be suppressed. In addition, it is possible to solve the problem that the distance resolution, which is a disadvantage of the prior art, is doubled, and to solve the ambiguity of the relative speed result.

Embodiment 11 FIG.
The configuration of the pulse radar device according to the eleventh embodiment of the present invention is basically the same as that of the tenth embodiment shown in FIG. However, in the tenth embodiment, the operation of the variable frequency oscillator 1 is different from the signal processing of the relative velocity measuring device 14 and the relative velocity correction synthesis band processor 15. Hereinafter, Embodiment 11 will be described with reference to FIG. 17 showing an example of a transmission frequency sequence in this embodiment. The description will be made of operations of the variable frequency oscillator 1, the relative speed measuring device 14, and the relative speed correction / synthesis band processing. Other processes and operations are the same as those in the tenth embodiment.

In the variable frequency oscillator 1, the transmission frequency sequence of transmitter 4, can switch arbitrarily to the transmission frequency sequence described in Embodiment 1 to 10 embodiment, for example, the time shift T _S transmission frequency sequence as shown in Figure 17 It can be set to a transmission frequency sequence (selectable by switching arbitrarily, and repeatedly output after a predetermined time). For example, in Figure 17 the time shift _{T S} is _{2T PRI.}

  As described in the first embodiment, when the frequencies oscillated for each pulse repetition period are arranged in ascending order, the frequency difference between adjacent frequencies is an integral multiple of a predetermined frequency interval Δf. For example, FIG. In this case, 2Δf which is twice the predetermined frequency interval Δf.

  The relative velocity measuring device 14 performs relative velocity measurement using the digital complex video signal subjected to MTI processing by the MTI processor 19. As shown in the lower diagram of FIG. 17, the digital complex video signal is divided into two sections and relative velocity measurement is performed. As the relative speed measurement method, for example, there is a method shown in the ninth embodiment.

  In the relative speed correction synthesis band processor 15, the relative speed ambiguity resolution processor 18 receives the relative speed from which the relative speed ambiguity has been resolved from the relative speed measuring instrument 14, performs relative speed correction, and performs synthesis band processing. .

  In the eleventh embodiment, the relative speeds that can be obtained are, for example, two of section 1 and section 2 as shown in the lower diagram of FIG. The relative speed correction combined band processor 15 corrects the relative speed using the relative speed corresponding to each section and performs combined band processing. The composite band processing is performed using, for example, the digital complex video signal obtained in the sections 1 and 2 shown in the lower diagram of FIG. Of course, the relative speed may be corrected by the average value of the relative speeds obtained in the sections 1 and 2, and the combined band process may be performed.

  As described above, by using the eleventh embodiment, a pulse radar device that performs high-range resolution ranging by combining band processing maintains speed measurement performance equal to or higher than that of the prior art with less observation time. However, it is difficult for the target to detect the transmission signal of the radar, and the frequency between the transmission pulses is hardly close, so that the multi-order echo can be suppressed. Further, clutter (unnecessary signal) typified by a stationary target or the like can be suppressed. In addition, it is possible to solve the problem that the distance resolution, which is a disadvantage of the prior art, is doubled, and to solve the ambiguity of the relative speed result.

  Needless to say, the present invention is not limited to the above embodiments, and includes all possible combinations thereof.

  The pulse radar device of the present invention can be used for, for example, a device for tracking a target aircraft or an air traffic control radar.

  DESCRIPTION OF SYMBOLS 1 Variable frequency oscillator, 2 reference | standard intermediate frequency signal oscillator, 3a, 3b Frequency converter, 4 Transmitter, 5 Transmission / reception switch, 6 Antenna, 7 Amplifier, 8 Divider, 9a, 9b Phase detector, 10 90 degree hybrid 11a, 11b Filter processor, 12a, 12b A / D converter, 13 Video signal memory, 14 Relative velocity measuring device, 15 Relative velocity correction synthesis band processor, 16 Envelope detector, 17 Tracking processor, 18 Relative speed ambiguity resolution processor, 19 MTI processor.

Claims (9)

A signal sequence having a frequency corresponding to a frequency sequence of an arbitrary pattern in which the frequency difference between adjacent frequencies is an integral multiple of a predetermined frequency interval when the frequencies are arranged in order of frequency without overlapping the frequency. A variable frequency oscillator that outputs in a repeating cycle;
Transmitting means for generating a pulse signal obtained by pulsing a transmission carrier signal generated by a signal sequence from the variable frequency oscillator and a reference intermediate frequency signal and transmitting the pulse signal as a transmission signal;
A reception video signal is generated based on a reflection signal from the target and background obtained at each pulse repetition period by the transmission signal of the transmission means, a signal sequence from the variable frequency oscillator, and the same reference intermediate frequency signal as the transmission signal And a receiving means including a filter function for cutting off frequency components other than the frequency band of the reflected signal;
A relative velocity measuring device for measuring the relative velocity of the target from the received video signal;
A relative speed correction synthesis band processor that performs a relative speed correction and a synthesis band processing on the received video signal according to the relative speed obtained by the relative speed measuring device;
Obtaining an amplitude value of an output of the relative velocity correction synthesis band processor, and outputting an object high-resolution ranging result by the synthesis band processing; an envelope detector;
A pulse radar device comprising:   The variable frequency oscillator includes a second frequency sequence in which a frequency difference between the first frequency sequence and the first frequency sequence is a predetermined number, and the predetermined pulse repetition period. 2. The pulse radar device according to claim 1, wherein a signal having a frequency corresponding to the first frequency train is output, and a signal having a frequency corresponding to the second frequency train is output after a predetermined time.   The variable frequency oscillator includes a second frequency sequence in which a frequency sum of the frequency sequence of the first frequency sequence and the first frequency sequence is constant, and the predetermined pulse repetition period. 2. The pulse radar device according to claim 1, wherein a signal having a frequency corresponding to the first frequency train is output, and a signal having a frequency corresponding to the second frequency train is output after a predetermined time.   The variable frequency oscillator includes a second frequency sequence in which a frequency difference between the first frequency sequence and the first frequency sequence is a predetermined number, and the predetermined pulse repetition period. The pulse radar device according to claim 1, wherein a signal having a frequency corresponding to the first frequency train and a signal having a frequency corresponding to the second frequency train are alternately output.   The variable frequency oscillator includes a second frequency sequence in which a frequency sum of the frequency sequence of the first frequency sequence and the first frequency sequence is constant, and the predetermined pulse repetition period. The pulse radar device according to claim 1, wherein a signal having a frequency corresponding to the first frequency train and a signal having a frequency corresponding to the second frequency train are alternately output.   6. The pulse radar device according to claim 2, wherein the frequency of the first frequency train of the variable frequency oscillator increases or decreases at a predetermined frequency interval. A relative speed ambiguity resolution processor;
The variable frequency oscillator selects and sequentially switches the frequency sequence according to claims 2 to 6 and outputs a signal sequence having a frequency corresponding to the selected frequency sequence,
The relative velocity measuring device measures the target relative velocity a plurality of times by the received video signal based on the signal sequence from the variable frequency oscillator,
Measurement when the relative speed ambiguity resolution processor has a good speed resolution based on the measurement result when the maximum observed speed without ambiguity is large among the target relative speed measurement results measured by the relative speed measuring device a plurality of times. To resolve the ambiguity of the results
The relative speed correction synthesis band processor performs a synthesis band process by correcting a relative speed with respect to the received video signal based on the target relative speed whose ambiguity has been resolved by the relative speed ambiguity resolution processor;
The pulse radar device according to claim 1. An MTI processor and a relative speed ambiguity resolution processor;
The variable frequency oscillator arbitrarily switches and selects the frequency sequence according to claim 2, and repeatedly outputs a signal sequence having a frequency corresponding to the selected frequency sequence after a predetermined time,
The MTI processor is a reflected signal from the background by MTI processing for the received video signal based on the signal sequence of the same frequency among the received video signals obtained based on the signal sequence from the variable frequency oscillator. Clutter suppression,
The relative velocity measuring device measures the target relative velocity a plurality of times based on the received video signal subjected to the MTI processing,
Measurement when the relative speed ambiguity resolution processor has a good speed resolution based on the measurement result when the maximum observed speed without ambiguity is large among the target relative speed measurement results measured by the relative speed measuring device a plurality of times. To resolve the ambiguity of the results
The relative speed correction synthesis band processor performs a synthesis band process on the received video signal subjected to the MTI process by performing a relative speed correction based on the target relative speed from which ambiguity is eliminated;
The pulse radar device according to claim 1.   The tracking processor which tracks a target from the distance value obtained from the envelope detector and the relative velocity obtained by the relative velocity measuring device is provided. Pulse radar equipment.

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