JP2011247776A - Radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar device employing a multi-frequency pulse system, which has improved S/N ratio and distance measurement accuracy.SOLUTION: The radar device includes: transmission/reception systems 1 to 6 which alternately transmit a low-power pulse for short distance and a high-power pulse for long distance while changing a transmission frequency and output the pulse for short distance and the pulse for long distance, which are reflected from a target, after allowing them to pass through with specific restrictions on frequency band; and distance measurement systems 7 to 11 which measure a distance to the target in accordance with the output of the transmission/reception systems. The radar device also includes a composite band transmitter 1 which steps a transmission frequency when the transmission/reception systems generate and transmit the pulse for short distance and the pulse for long distance and switch between the pulse for long distance and the pulse for short distance.

Description

  The present invention relates to a radar apparatus for detecting a target.

  For example, in the double pulse method disclosed in Patent Document 1 below, a short pulse (short pulse for short distance target) for detecting a short distance target having a high S / N ratio and a long distance target having a low S / N ratio are disclosed. A further improvement of the detection function is expected by performing double pulse transmission / reception in which long pulses for detection (long pulses for long-distance targets) are alternately transmitted and received.

Japanese Patent Laid-Open No. 50-104889

  However, in the conventional method, the interference between the short-distance pulse and the long-distance pulse reflected from the long-distance target, or the time determined from the transmission of the long-distance pulse to the transmission of the next short-distance pulse is determined. There was a problem that the long-distance pulse reflected by the target farther than the range interferes with the next short-distance pulse and the ranging accuracy deteriorates.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a double-pulse radar device that improves the S / N ratio and improves the ranging accuracy.

  The present invention alternately transmits a short-distance pulse with a small power and a long-distance pulse with a large power while changing the transmission frequency, and the short-distance pulse and the long-distance pulse reflected at the target are band-limited at different frequencies. A radar apparatus comprising: a transmission / reception system that outputs after passing through and a distance measurement system that measures a distance from the output of the transmission / reception system to the target.

  According to the present invention, it is possible to provide a double-pulse type radar apparatus that improves the S / N ratio and improves the ranging accuracy.

It is a figure which shows the structure of the radar apparatus by Embodiment 1 of this invention. It is a figure which shows an example of an internal structure of the synthetic | combination zone | band type long distance target ranging means of FIG. It is a figure which shows an example of an internal structure of the synthetic | combination zone | band type | mold short distance target ranging means of FIG. It is a figure which shows an example of an internal structure of the super-resolution ranging means of FIG. It is an operation | movement time chart of the synthetic | combination band type | mold transmitter of FIG. It is a figure for demonstrating the effect of the radar apparatus of FIG. It is a figure which shows the structure of the radar apparatus by Embodiment 2 of this invention. It is an operation | movement time chart of the near-far order type | mold synthetic band type | mold transmitter of FIG. It is a figure which shows the structure of the radar apparatus by Embodiment 3 of this invention. It is a figure which shows an example of an internal structure of the multi-frequency step ICW type long distance target ranging means of FIG. It is a figure which shows an example of an internal structure of the multi-frequency step ICW type | mold short distance target distance measuring means of FIG. 10 is an operation time chart of the multi-frequency step ICW type transmitter of FIG. 9. It is a figure which shows the structure of the radar apparatus by Embodiment 4 of this invention. It is an operation | movement time chart of the near-far order type | mold multi-frequency step ICW type | mold transmitter of FIG. It is a figure which shows the structure of the radar apparatus by Embodiment 5 of this invention. It is a figure which shows the structure of the radar apparatus by Embodiment 6 of this invention. It is a figure which shows the structure of the radar apparatus by Embodiment 7 of this invention. It is a figure which shows an example of an internal structure of the synthetic | combination zone | band type long distance target ranging means with a sort function of FIG. It is a figure which shows an example of an internal structure of the synthetic | combination zone | band type short distance target ranging means with a sort function of FIG. It is an operation | movement time chart of the perspective individual type synthetic | combination band type | mold transmitter of FIG. It is a figure which shows the structure of the radar apparatus by Embodiment 8 of this invention. It is a figure which shows an example of an internal structure of the multi-frequency step ICW type long distance target measuring means with a sort function of FIG. It is a figure which shows an example of an internal structure of the multi-frequency step ICW type | mold short-distance target ranging means with a sort function of FIG. FIG. 22 is an operation time chart of the perspective individual multi-frequency step ICW type transmitter of FIG. 21. It is a figure which shows the structure of the radar apparatus by Embodiment 9 of this invention. It is a figure which shows an example of the frequency shift in the radar apparatus by Embodiment 9 of this invention. It is a figure for demonstrating the leak of the pulse for short distance reflected in the long distance target by enlarging the step frequency in the radar apparatus by Embodiment 9 of this invention. It is a figure which shows the structure of the radar apparatus by Embodiment 10 of this invention. FIG. 29 is an operation time chart of the near-far order type wide frequency step interval type synthetic band type transmitter of FIG. 28. It is a figure which shows the structure of the radar apparatus by Embodiment 11 of this invention. It is a figure which shows the structure of the radar apparatus by Embodiment 12 of this invention. FIG. 32 is an operation time chart of the near-far order type wide frequency step interval type multi-frequency step ICW type transmitter of FIG. 31. It is the figure which showed the structural example of the system which performs a ranging process using the general double pulse relevant to this invention. It is the figure which showed the example of an internal structure of the pulse compression means of FIG. It is an operation | movement time chart of the structure of FIG. It is a figure for demonstrating the problem of the structure of FIG.

  First, the problem of the double pulse radar device will be described in a little more detail. FIG. 33 shows a configuration example of a method for performing a distance measurement process using a general double pulse. 41 is a transmitter that outputs a short-distance pulse and a long-distance pulse, 2 is a circulator that switches between transmission and reception of radio waves, 3 is a transmission / reception antenna that transmits or receives radio waves, 4 is a target, and 5 is a reception pulse and transmission Mixer for mixing pulses, 6 for band limitation of mixer output signal, receiver for phase detection, 7 for A / D converter for sampling analog signal and generating digital signal, 8 for processing for short distance target A changeover switch for switching processing for a long distance target, 12 is a pulse compression means for improving the S / N ratio (signal to noise power ratio), and 42 is a target distance measurement means for estimating a target distance. FIG. 34 shows the internal configuration of the pulse compression means 12. 43 is an FFT means for performing FFT (Fast Fourier Transform) processing on the input signal, 44 is a multiplication means for performing complex multiplication between components of the input signal, and 45 is an IFFT (Inverse Fast Fourier Transform) for the input signal. IFFT means for performing conversion.

Next, the operation will be described. A pulse is generated by the transmitter 41 and transmitted from the transmitting / receiving antenna 3 through the circulator 2. FIG. 35 shows the operation time chart. First, a short pulse (short-distance target pulse) for measuring a short-distance target is transmitted. The short-distance pulse reflected by the target 4 is received by the transmission / reception antenna 3 again. The received short-distance pulses are mixed with a reference signal (transmission pulse) by the mixer 5 and then band-limited and phase-detected by the receiver 6. The receiver output signal is sampled by the A / D converter 7 with a period T _samp and a digital signal is output. The nr (1 ≦ nr ≦ N _r ) th sampled A / D conversion output signal is expressed as s ″ _nr (nr = 1, 2,...). Here, nr represents a range bin number. The A / D conversion output signal s ″ _nr is transmitted to the target distance measuring means 42 by the changeover switch 8. The target distance measuring means 42 compares the power value | s '' _nr | ^{2 of} the A / D conversion output signal and the false alarm probability (probability that noise is mistaken as the target signal) with a threshold determined based on the range bin estimated value ( Tilde) Find _nr . Then, using the range bin estimated value (tilde) n _r , a distance measurement value (tilde) r is obtained by the following equation (1). In the following formula (1), c represents the speed of light.

Next, a pulse (far-distance target pulse) _unr that has been subjected to code modulation for distance measurement of the far-distance target is transmitted. The pulse reflected by the target 4 is received by the transmitting / receiving antenna 3 again. The received long-distance pulse is mixed with a reference signal (transmission pulse) by the mixer 5 and then band-limited and phase-detected by the receiver 6. The receiver output signal is sampled by the A / D converter 7 with a period T _samp and a digital signal is output. An A / D conversion output signal s ′ _nr (nr = 1, 2,...) Is transmitted to the pulse compression means 12 by the changeover switch 8. In the pulse compression means 12 of FIG. 34, the long distance pulse _unr and the A / D converter output signal s ′ _nr are transmitted to the respective FFT means 43. The long distance pulse u _nr is subjected to FFT to calculate the frequency spectrum uf _nr of the long distance pulse. _Nr 'frequency spectrum sf of _nr' A / D conversion output signal s is calculated in the same manner. The frequency spectra uf _nr and sf ′ _nr are transmitted to the multiplication means 44. The multiplication unit 44 generates a multiplication signal sf _nr by the following equation (2). In the following equation, (sf _nr ) * represents a complex conjugate of sf _nr .

The multiplication signal sf _nr is transmitted to the IFFT means 45. IFFT is performed on the IFFT unit 45 the multiplier signal sf _nr generates a pulse compression signal s _nr. The pulse compression signal s _nr is transmitted to the target distance measuring means 42. Thereafter, processing similar to that for the short-distance pulse is performed, and the distance measurement value is obtained by Expression (1).

  However, in the above method, the short-range pulse and the long-distance pulse interference reflected by the long-distance target, or an observation determined from the time from when the long-distance pulse is transmitted until the next short-distance pulse is transmitted. There is a problem that the long-range pulse reflected by the target farther than the range interferes with the next short-range pulse, and the ranging accuracy is deteriorated. FIG. 36 shows an example of this situation. There are two targets (target 1 and target 2) in the long distance range, and the short distance pulse reflected by the long distance target 1 and the long distance pulse reflected by the long distance target 2 are mixed. In view of this, the present invention provides a double-pulse radar device that improves the S / N ratio and improves the ranging accuracy.

  Hereinafter, a radar device according to the present invention will be described with reference to the drawings according to each embodiment. In addition, in each embodiment including the above-mentioned general radar apparatus, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
1 is a diagram showing a configuration of a radar apparatus according to Embodiment 1 of the present invention. 1 is a combined-band transmitter for performing transmission and reception while stepping the frequency (for example, changing the frequency stepwise (increase or decrease)), 2 is a circulator that switches between transmission and reception of radio waves, and 3 is transmission or reception of radio waves Transmission / reception antenna for receiving, 4 is target, 5 is a mixer that mixes received and transmitted pulses, 6 is a receiver that limits the band of mixer output signal and performs phase detection, 7 is a digital signal by sampling analog signal An A / D converter 8 is a change-over switch for switching between short-distance target processing and long-distance target processing. 9 is a memory circuit # 1 for storing received signals and memory circuits # 2 and 10 are synthetic band-type far-distance target ranging which performs distance-distance target ranging processing assuming pulse transmission / reception of a synthetic band-type transmitter. Means 11 is a synthetic band type short distance target ranging means for performing a distance measurement process assuming a short distance target assuming pulse transmission / reception of the synthetic band type transmitter.

FIG. 2 is a diagram showing an example of the internal configuration of the synthetic band type long distance target distance measuring means 10 of FIG. 12- # 1 to 12- # N are pulse compression means for improving the S / N ratio. Reference numeral 13 denotes a composite band type target detection means for performing target detection processing assuming pulse transmission / reception by the composite band type transmitter 1, and reference numeral 14 denotes a super-resolution distance measurement means for measuring the target distance with a resolution higher than the range resolution.
FIG. 3 is a diagram showing an example of the internal configuration of the synthetic band type short distance target distance measuring means 11 of FIG. The synthetic band type target detecting means 13 and the super-resolution distance measuring means 14 are the same as those in FIG.
FIG. 4 is a diagram showing an example of the internal configuration of the super-resolution ranging means 14 shown in FIGS. 15 is a correlation matrix generating means for generating a correlation matrix representing a correlation between transmission frequencies of input signals, 16 is a MUSIC eigenvector calculating means for calculating an eigenvector for performing MUSIC (MUltiple SIgnal Classification) processing, and 17 is a MUSIC process. MUSIC processing means to be performed.

Next, the operation will be described. According to the operation time chart of FIG. 5 from the composite band type transmitter 1, first, a long distance (target) pulse subjected to code modulation of the transmission frequency f ₁ (code modulation in units of chip width determined from the reciprocal of the transmission bandwidth) Are generated and output from the transmitting / receiving antenna 3 through the circulator 2. The long-distance pulse reflected by the target 4 is received by the transmission / reception antenna 3 again. The received long-distance pulse is mixed with the long-distance pulse transmitted by the mixer 5 and then subjected to band limitation and phase detection by the receiver 6. At this time, the frequency of the reference signal (received long-distance pulse) is equal to the transmission frequency of the transmitted long-distance pulse. The output signal of the receiver 6 is sampled by the A / D converter 7 with a period T _samp , and the A / D conversion output signal s ′ _{1, nr} is stored in the memory circuit 9-# 1 by the changeover switch 8. A short-distance (target) pulse (having a pulse width determined by the reciprocal of the transmission bandwidth) of the transmission frequency f ₁ is transmitted and processed in the same manner as the long-distance pulse. The signal s ″ _{1, nr} is stored in the memory circuit 9- # 2.

Next, the transmission frequency is stepped and the same transmission / reception is performed. This operation is repeated. That is, during the transmission period, for example, a long-distance pulse and a short-distance pulse are switched in order (or short-distance pulse and long-distance pulse, as will be described later), and are generated, transmitted, and repeated. By transmitting the pulse for long distance and the pulse for short distance alternately, and changing the transmission frequency every time switching from the pulse for short distance to the pulse for long distance (or vice versa) Transmit by stepping the transmission frequency. By repeating this operation, the A / D conversion output signal s ′ _{n, nr} (1 ≦ n ≦ N) is stored in the memory circuit 9- # 1. The memory circuit 9- # 2 stores an A / D conversion output signal s ″ _{n, nr} (1 ≦ n ≦ N).

The A / D conversion output signal s ′ _{n, nr} is transmitted from the memory circuit 9- # 1 to the pulse compression means 12- # n shown in FIG. The pulse compression means 12- # n operates in the same manner as the above general apparatus and outputs a pulse compression signal _{sn, nr} . The pulse compression signal _{sn, nr} is transmitted to the synthesis band type target detection means 13. The combined band type target detection means 13 compares the power value | s _{n, nr} | ^{2 of} the pulse compression signal s _{n, nr} with the threshold defined based on the false alarm probability (probability that noise is mistaken as the target signal). Estimated value

Ask for. And target signal

Is output. Target signal

Is transmitted to the correlation matrix generating means 15 shown in FIG. The correlation matrix generating means 15 uses the equation (3) to calculate the correlation matrix.

Is generated.

  Where M is the number of dimensions of the correlation matrix,

Is a vector

Represents the conjugate transpose of. Correlation matrix

Is transmitted to the MUSIC eigenvector calculation means 16. In the eigenvector calculation means 16 for MUSIC, the correlation matrix

Eigenvalues of

And eigenvalues

The eigenvector corresponding to

Ask for. eigenvalue

The target number K is estimated from the size of. And the eigenvector

Is output. Eigenvector

Is transmitted to the MUSIC processing means 17. In the MUSIC processing means 17, the eigenvector

MUSIC (MUltiple SIgnal Classification) processing is performed with the noise space. Specifically, a steering vector a (r) is generated by Equation (4) with the target distance as r,

Eigenvector

K types of steerings a (r) orthogonal to all of the above are obtained. R at this time

And

Represents the distance of the kth target. With the above processing, the distance is obtained for K types of long-distance targets that are closer than the Doppler resolution and range resolution.

Further, the A / D conversion output signal s ″ _{n, nr} output from the memory circuit 9- # 2 is transmitted to the combined band type target detecting unit 13 shown in FIG. Is done. Thereafter, processing similar to the processing of the long-distance pulse is performed, and the distance measurement value of each target is obtained.

  In the first embodiment, the frequency step is performed after transmitting the long-distance pulse, and the short-distance pulse reflected by the long-distance target is mixed with the long-distance pulse shifted by the step frequency. At the time of input, it becomes a frequency component outside the passband of the receiver. FIG. 6 shows the situation. Therefore, the short distance pulse reflected by the long distance target does not pass through the receiver band, and interference between the long distance pulse and the short distance pulse is reduced.

Embodiment 2. FIG.
FIG. 7 is a diagram showing a configuration of a radar apparatus according to Embodiment 2 of the present invention. Reference numeral 18 denotes a near-far order type synthetic band transmitter that performs frequency transmission by transmitting and receiving pulses in the order of short distance pulses and long distance pulses. The other parts basically correspond to the corresponding parts of the first embodiment.

Next, the operation will be described. According to the operation time chart of FIG. 8, first, a short-distance pulse having a transmission frequency f ₁ is generated from the near-far sequence type combined band transmitter 18 and output from the transmitting / receiving antenna 3 through the circulator 2. Thereafter, the same operation as in the first embodiment is performed, and the A / D conversion output signal s ″ _{1, nr} is stored in the memory circuit 9- # 2. Further, a long-distance pulse having a transmission frequency f ₁ is transmitted and operates in the same manner as in the first embodiment, and the A / D conversion output signal s ′ _{1, nr} is stored in the memory circuit 9- # 1. Next, the transmission frequency is stepped to perform similar transmission / reception. By repeating this operation, the A / D conversion output signal s ′ _{n, nr} (1 ≦ N ≦ N) is stored in the memory circuit 9- # 1. The memory circuit 9- # 2 stores an A / D conversion output signal s ″ _{n, nr} (1 ≦ n ≦ N). Thereafter, the same operation as in the first embodiment is performed to obtain a distance measurement value.

  In the second embodiment, the frequency step is performed after the short-distance pulse is transmitted, and the long-distance pulse reflected by the target far away from the observation range is mixed with the short-distance pulse shifted by the step frequency. That is, when the receiver is input, the frequency component is outside the passband of the receiver. For this reason, since the short-distance pulse reflected by the long-distance target does not pass through the receiver band, interference between the long-distance pulse and the short-distance pulse is reduced.

Embodiment 3 FIG.
FIG. 9 is a diagram showing a configuration of a radar apparatus according to Embodiment 3 of the present invention. 19 is a multi-frequency step ICW (Interrupted Continuous Wave) transmitter that repeats a frequency sweep pattern a plurality of times, and 20 is a multi-frequency step ICW type long-distance target ranging that detects and measures a long-distance target signal in the Doppler frequency domain. Means 21 is a multi-frequency step ICW type near-distance target distance measuring means for detecting and measuring a short-distance target signal in the Doppler frequency domain. The other parts basically correspond to the corresponding parts of the first embodiment.

  FIG. 10 is a diagram showing an example of the internal configuration of the multi-frequency step ICW type long distance target distance measuring means 20 of FIG. The pulse compression means 12- # n and the super-resolution distance measurement means 14 are the same as those in the first embodiment. 22- # n is a pulse hit direction FFT unit for obtaining a Doppler frequency from the phase change of the target signal with respect to the pulse hit direction, and 23 is a multi-frequency step ICW that performs target detection processing assuming pulse transmission / reception by the multi-frequency step ICW transmitter 19. The mold target detection means, 24- # n, is Doppler correction means for correcting the phase rotation of the target signal rotated by the Doppler.

  FIG. 11 is a diagram showing an example of the internal configuration of the multi-frequency step ICW type short distance target distance measuring means 21 of FIG. The super-resolution ranging means 14 is the same as that in the first embodiment. 22- # n is a pulse hit direction FFT unit for obtaining a Doppler frequency from the phase change of the target signal with respect to the pulse hit direction, and 23 is a multi-frequency step ICW that performs target detection processing assuming pulse transmission / reception by the multi-frequency step ICW transmitter 19. The mold target detection means, 24- # n, is Doppler correction means for correcting the phase rotation of the target signal rotated by the Doppler.

Next, the operation will be described. Pulse transmission / reception is performed from the multi-frequency step ICW type transmitter 19 according to the operation time chart of FIG. 12, and the operation is the same as in the first embodiment, and the A / D conversion is performed in the memory circuit 9- # 1 and the memory circuit 9- # 2. Output signals s ′ _{n, 1, nr} and s ″ _{n, 1, nr} are stored, respectively. The above operation is repeated N _p times, and finally the memory circuit 9- # 1 and the memory circuit 9- # 2 have s ′ _{n, np ,, nr} and s ″ _{n, np ,, nr} (1 ≦ n _p ≦ N _p ) is stored. Here, n _p represents a pulse hit number. An A / D converter output signal s ′ _{n, np, nr} is output from the memory circuit 9- # 1 _{, and} is sent to the pulse compression means 12- # n shown in FIG. Communicated. Pulse compression processing is performed in the same manner as in the first embodiment, and pulse compression signals _{sn, np, nr} are transmitted to the pulse hit direction FFT unit 22- # n. In the pulse hit direction FFT unit 22- # n, a Doppler signal _{pn, nd, nr} (0 ≦ n _d ≦ N _p −1), which is a Doppler frequency component of the A / D conversion output signal s _{n, np, nr} , is (5) is calculated. In Expression (5), w _np represents a weight when performing FFT.

The Doppler signals p _{1, nd, nr} ,..., P _{N, nd, nr} are transmitted to the multi-frequency step ICW type target detection means 23 and the Doppler correction means 24- # n. In the multi-frequency step ICW type target detection means 23, the power value | p _{n, nd, nr} | ^{2 of} the Doppler signal _{pn, nd, nr} and the false alarm probability (probability that the noise is mistaken as the target signal) are determined as a reference. Compared with the threshold, a set ((tilde) n _d , (tilde) n _r ) of the estimated value (tilde) n _{r of} the range bin in which the target signal exists and the estimated value (tilde) n _d of the Doppler bin is obtained. By the following equation (6), calculates each pair ((tilde) n _d, (tilde) n _r) of the corresponding target velocity estimate (tilde) v ((tilde) n _d, (tilde) n _r) . At this time, a transmission frequency f _n0 having a predetermined number n ₀ is used. C represents the speed of light, and T _PRI represents the repetition period of the same transmission frequency.

Range bin estimated value and velocity estimated value pair ((tilde) n _d , (tilde) n _r ) and corresponding target velocity estimated value (tilde) v ((tilde) n _d , (tilde) n _r ) are Doppler corrected. Is transmitted to means 24- # n. In the Doppler correction means 24- # n, the Doppler correction signal is expressed by the following equation (7).

Ask for.

  Doppler correction signal

Is transmitted to the super-resolution ranging means 14. Thereafter, the same operation as in the first embodiment is performed, and distances are obtained for K types of long-distance targets closer than the Doppler resolution and range resolution.

Further, the A / D conversion output signals s ″ _{n, np, and nr} output from the memory circuit 9- # 2 are converted into the pulse hit direction FFT shown in FIG. Is transmitted to the unit 22- # n. Thereafter, the same processing as the processing of the long-distance pulse after the pulse hit direction FFT unit 22- # n in FIG. 10 is performed, and the ranging value of each target is obtained.

  In the third embodiment, the frequency step is performed after transmitting the long-distance pulse, and the short-distance pulse reflected by the long-distance target is mixed with the long-distance pulse shifted by the step frequency. At the time of input, it becomes a frequency component outside the passband of the receiver. Therefore, the short-distance pulse reflected by the long-distance target does not pass through the receiver band. Therefore, the short distance pulse reflected by the long distance target does not pass through the receiver band, and interference between the long distance pulse and the short distance pulse is reduced. In addition, there is an effect of improving the S / N ratio by the pulse hit direction FFT section, and the target detection performance is improved.

Embodiment 4 FIG.
FIG. 13 is a diagram showing the configuration of a radar apparatus according to Embodiment 4 of the present invention. Reference numeral 25 denotes a near-far order multi-frequency step ICW transmitter which performs frequency transmission by transmitting and receiving pulses in the order of short distance pulses and long distance pulses. The other parts basically correspond to the corresponding parts of the third embodiment.

Next, the operation will be described. Pulse transmission / reception is performed in accordance with the operation time chart of FIG. 14 from the near-far sequence type multi-frequency step ICW type transmitter 25, and operates in the same manner as in the second embodiment, and the memory circuit 9- # 1 and the memory circuit 9- # 2 A / D converter output signals s ′ _{n, 1, nr} and s ″ _{n, 1, nr} are stored, respectively. The above operation is repeated N _p times, and finally the memory circuit 9- # 1 and the memory circuit 9- # 2 have s ′ _{n, np ,, nr} and s ″ _{n, np ,, nr} (1 ≦ n _p ≦ N _p ) is stored. Thereafter, the same operation as in the third embodiment is performed to obtain a distance measurement value.

  In the fourth embodiment, the frequency step is performed after transmitting the short-distance pulse, and the long-distance pulse reflected by the target farther than the observation range is mixed with the short-distance pulse shifted by the step frequency. That is, when the receiver is input, the frequency component is outside the passband of the receiver. Therefore, the short distance pulse reflected by the long distance target does not pass through the receiver band, and interference between the long distance pulse and the short distance pulse is reduced. In addition, there is an effect of improving the S / N ratio by the pulse hit direction FFT section, and the target detection performance is improved.

Embodiment 5 FIG.
FIG. 15 is a diagram showing a configuration of a radar apparatus according to Embodiment 5 of the present invention. 26 is a transmission order variable type combined band type transmitter capable of switching the transmission order of short distance pulses and long distance pulses to a desired order, and 27 is a switching determination for determining transmission of short distance pulses or long distance pulses. Circuit. The other parts basically correspond to the corresponding parts of the first embodiment.

  Next, the operation will be described. Transmission / reception is performed using a short-distance pulse and a long-distance pulse according to a predetermined order set in advance. In the order of the long distance pulse and the short distance pulse, the operation is the same as in the first embodiment. In the order of the short distance pulse and the long distance pulse, the operation is the same as in the second embodiment. Then, the distance measurement value is obtained. The distance measurement value is transmitted to the switching determination circuit 27.

  In the switching determination circuit 27, for example, by checking the distortion of the waveform of the received pulse, the suppression effect in the band of the receiver 6 is small, and interference between the short-distance pulse and the long-distance pulse reflected by the long-distance target can be seen. Is transmitted to the transmission order variable type synthetic band transmitter 26 so as to transmit in the order of long-distance pulses and short-distance pulses. In that case, the transmission order variable type synthetic band type transmitter 26 performs transmission / reception in the order of the long distance pulse and the short distance pulse and operates in the same manner as in the first embodiment. A distance measurement value is obtained by means 10 and synthetic band type short distance target distance measurement means 11. Also, in a situation where interference between the long-distance pulse and the short-distance pulse reflected on the target far away from the observation range is observed, the transmission order is variable so that the short-distance pulse and the long-distance pulse are transmitted in this order. This is transmitted to the composite band type transmitter 26. In this case, the transmission order variable type synthetic band type transmitter 26 performs transmission / reception in the order of short distance pulses and long distance pulses, and operates in the same manner as in the second embodiment, thereby performing synthetic band type long distance target measurement. A distance measurement value is obtained by the distance means 10 and the synthetic band type short distance target distance measurement means 11.

  In the fifth embodiment, the pulse transmission order is switched according to the observed target situation, and distance measurement can be performed without interference between the short-distance pulse and the long-distance pulse.

Embodiment 6 FIG.
FIG. 16 is a diagram showing a configuration of a radar apparatus according to Embodiment 6 of the present invention. The switching determination circuit 27 corresponds to that of the fifth embodiment. Reference numeral 28 denotes a transmission order variable type multi-frequency step ICW transmitter capable of switching the transmission order of short distance pulses and long distance pulses to a desired order. The other parts basically correspond to the corresponding parts of the third embodiment.

  Next, the operation will be described. Transmission / reception is performed using a short-distance pulse and a long-distance pulse according to a predetermined order set in advance. In the order of the long distance pulse and the short distance pulse, the operation is the same as in the third embodiment. In the order of the short distance pulse and the long distance pulse, the operation is the same as in the fourth embodiment. Then, the distance measurement value is obtained. The distance measurement value is transmitted to the switching determination circuit 27.

  In the switching determination circuit 27, for example, by examining the distortion of the waveform of the received pulse, the interference effect between the short-distance pulse and the long-distance pulse reflected by the long-distance target is small because the suppression effect in the receiver band is small. Is transmitted to the transmission order variable type multi-frequency step ICW transmitter 28 so as to transmit in the order of long-distance pulses and short-distance pulses. In that case, the transmission order variable type multi-frequency step ICW type transmitter 28 performs transmission and reception in the order of long-distance pulses and short-distance pulses, and operates in the same manner as in the third embodiment. A distance measurement value is obtained by the target distance measurement means 20 and the multi-frequency step ICW type short distance target distance measurement means 21. Also, in a situation where there is interference between the long-distance pulse and the short-distance pulse reflected from the target far away from the observation distance range, the transmission order can be changed so that the short-distance pulse and long-distance pulse are transmitted in this order. Type multi-frequency step ICW transmitter 28. In this case, the transmission order variable type multi-frequency step ICW type transmitter 28 performs transmission and reception in the order of short-distance pulses and long-distance pulses, and operates in the same manner as in the fourth embodiment. A distance measurement value is obtained by the distance target distance measurement means 20 and the multi-frequency step ICW type short distance target distance measurement means 21.

  In the sixth embodiment, the pulse transmission order is switched according to the observed target condition, and distance measurement can be performed without interference between the short-distance pulse and the long-distance pulse.

Embodiment 7 FIG.
FIG. 17 is a diagram showing a configuration of a radar apparatus according to Embodiment 7 of the present invention. 30 is a perspective individual type combined-band transmitter that switches the transmission frequency each time the pulse for long distance and the pulse for short distance are switched, and 31 is a rearrangement of the pulses for long distance reflected by the target in order from the lowest transmission frequency. Combining band type long-distance target distance measuring means with sort function for performing distance measurement processing, 32 is a composition with sort function for performing distance measurement processing after rearranging short-distance pulses reflected by the target in order from the lowest transmission frequency This is a band-type short-distance target ranging means. The other parts basically correspond to the corresponding parts of the first embodiment.

  FIG. 18 is a diagram showing an example of the internal configuration of the combined band type long-distance target distance measuring means 31 with sort function of FIG. The pulse compression means 12- # 1 to 12- # N, the combined band type target detection means 13, and the super-resolution distance measurement means 14 are the same as those in the first embodiment. Reference numeral 33 denotes sorting means for rearranging the received signals in order from the lowest transmission frequency. FIG. 19 is a diagram showing an example of the internal configuration of the combined band type short distance target distance measuring means 32 with a sorting function in FIG. Like FIG. 2 and FIG. 3 and FIG. 10 and FIG.

Next, the operation will be described. In accordance with the operation time chart of FIG. In FIG. 20, f _{1, i} represents the transmission frequency of the long-distance pulse, and the frequency f _{1, i} (1 ≦ i ≦ N) is N frequencies with Δf as the step frequency and f ₀ as the minimum frequency. Assume that there is a one-to-one correspondence with f ₀ , f ₀ + Δf,..., f ₀ + (N−1) Δf. The long-distance pulse reflected by the target 4 is received by the transmission / reception antenna 3 and operates in the same manner as in the first embodiment. The pulse compression unit 12- # shown in FIG. transmitted to n. The subsequent operation is the same as in the first embodiment, and the target signal is sent to the sorting means 33.

Is transmitted. In the sorting means 33, the target signal

Sorted signal in which received signals are rearranged in order from the lowest transmission frequency

Is generated. Sort signal

Is transmitted to the super-resolution ranging means 14 to obtain a ranging value.

Next, according to the operation time chart of FIG. 20, short-distance pulses are transmitted from the perspective individual type combined band transmitter 30. f _{i, 2} represents the transmission frequency of the short-distance pulse, and the frequency f _{2, i} (1 ≦ i ≦ N) is defined as N frequency f ₀ , where Δf is the step frequency and f ₀ is the minimum frequency. Assume that there is a one-to-one correspondence with f ₀ + Δf,..., f ₀ + (N−1) Δf. Further, the transmission frequencies f _{1, i of} the long-distance pulses and the transmission frequencies f _{2, i} (1 ≦ i ≦ N) and f _{2, i} and f _{1, i + 1} (1 ≦ ₁ ) of the adjacent long-distance pulses. i ≦ N−1) is different. The short-distance pulse reflected by the target 4 is received by the transmission / reception antenna 3 and transmitted to the synthetic band-type target detecting means 13 of the synthetic band-type short-distance target ranging means 32 with sort function as in the first embodiment. The subsequent operation is the same as in the first embodiment, and the target signal is sent to the sorting means 33.

Is transmitted. The sorting means 33 rearranges the target signals in order from the lowest transmission frequency, and the super-resolution ranging means 14 obtains the ranging value.

  In Embodiment 7 above, the transmission frequency is switched for each pulse, and the short-distance pulse reflected by the long-distance target is mixed with the long-distance pulse having a different frequency component. The frequency component is out of the pass band and does not pass through the receiver band. For the same reason, a long-distance pulse reflected by a target far away from the observation range becomes a frequency component outside the pass band of the receiver and does not pass through the receiver band. Therefore, distance measurement can be performed without interference between the long-distance pulse and the short-distance pulse. In this embodiment, the long-distance pulse is transmitted first. However, the short-distance pulse may be transmitted first.

Embodiment 8 FIG.
FIG. 21 is a diagram showing a configuration of a radar apparatus according to Embodiment 8 of the present invention. Reference numeral 34 denotes a long-distance individual (type) multi-frequency step ICW type transmitter that switches the transmission frequency every time the long-distance pulse and the short-distance pulse are switched, and 35 denotes the short-distance pulse reflected by the target in order from the lowest transmission frequency. Multi-frequency step ICW type long-distance target ranging means with sorting function for performing ranging processing after rearrangement, 36 is a post-distance processing by rearranging short-distance pulses reflected by the target in order from the lowest transmission frequency This is a multi-frequency step ICW type short-distance target distance measuring means with a sort function for performing. The other parts basically correspond to the corresponding parts of the first embodiment.

  FIG. 22 is a diagram showing an example of the internal configuration of the multi-frequency step ICW type far-distance target distance measuring means 35 with sort function shown in FIG. Pulse compression means 12- # 1-12- # N, pulse hit direction FFT unit 22- # 1-22- # N, multi-frequency step ICW type target detection means 23, Doppler correction means 24- # 1-24- # N The super-resolution distance measuring means 14 is the same as that in the third embodiment. The sorting means 33 is the same as that in the seventh embodiment.

  FIG. 23 is a diagram showing an example of the internal configuration of the multi-frequency step ICW type short-range target distance measuring means 36 with sort function of FIG. The pulse hit direction FFT units 22- # 1 to 22- # N, the multi-frequency step ICW type target detection means 23, the Doppler correction means 24- # 1 to 24- # N, and the super-resolution ranging means 14 are the same as those in the third embodiment. The same. The sorting means 33 is the same as that in the seventh embodiment.

Next, the operation will be described. In accordance with the operation time chart of FIG. 24, a long-distance pulse is transmitted from the perspective individual multi-frequency step ICW transmitter 34. Thereafter, the A / D conversion output signals s ′ _{n, 1, nr} obtained by the long distance pulse transmission / reception are stored in the memory circuit 9- # 1 in the same manner as in the seventh embodiment. In addition, A / D conversion output signals s ″ _{n, 1, nr} obtained by short-distance pulse transmission / reception are stored in the memory circuit 9- # 2. By repeating the above operation N _p times, the A / D conversion output signal s ′ _{n, np, nr} is stored in the memory circuit 9- # 1, and the A / D conversion output signal s ″ _{n, np, nr} is stored in the memory. Stored in circuit 9- # 2.

The A / D conversion output signals s ′ _{n, np, nr} output from the memory circuit 9- # 1 are pulse compression means 12− shown in FIG. 22 of the multi-frequency step ICW type long distance measuring means 35 with sort function. #N is transmitted. Thereafter, the operation is the same as in the third embodiment, and the Doppler correction signal is operated.

Is transmitted to the sorting means 33. The sorting means 33 performs a Doppler correction signal.

Sorted signal in which received signals are rearranged in order from the lowest transmission frequency

Is generated. Sort signal

Is transmitted to the super-resolution ranging means 14 to obtain a ranging value.

The A / D conversion output signal s ″ _{n, np, nr} output from the memory circuit 9- # 2 is a pulse hit shown in FIG. The signal is transmitted to the direction FFT unit 22- # n. Thereafter, the same processing as the processing of the long-distance pulse after the pulse hit direction FFT unit 22- # n in FIG. 22 is performed, and the ranging value of each target is obtained.

  In the eighth embodiment, the transmission frequency is switched for each pulse, and the short-distance pulse reflected by the long-distance target is mixed with the short-distance pulse having a different frequency component. The frequency component is out of the pass band and does not pass through the receiver band. For the same reason, a long-distance pulse reflected by a target far away from the observation range becomes a frequency component outside the pass band of the receiver and does not pass through the receiver band. Therefore, distance measurement can be performed without interference between the long-distance pulse and the short-distance pulse. In this embodiment, the long-distance pulse is transmitted first. However, the short-distance pulse may be transmitted first.

Embodiment 9 FIG.
FIG. 25 is a diagram showing the configuration of a radar apparatus according to Embodiment 9 of the present invention. Reference numeral 37 denotes a wide frequency step-interval synthetic band transmitter that increases the step frequency to shift the transmission frequency. The other parts basically correspond to the corresponding parts of the seventh embodiment.

  Next, the operation will be described. In accordance with the same operation time chart of FIG. 20 as in the seventh embodiment, a long-distance pulse is transmitted from the wide frequency step interval type synthetic band transmitter 37. Here, it is assumed that the transmission frequency is shifted so that the frequency step interval is increased. FIG. 26 shows an example of such a frequency shift. When the transmission band is shifted as shown in (a) of FIG. 26, the step frequency is Δf. However, as shown in (b), the frequency is shifted by switching between a larger value and a smaller value, for example. The minimum step frequency is 2Δf, and the step frequency can be increased by a factor of two or more. The long-distance pulse reflected by the target 4 is received by the transmission / reception antenna 3, and thereafter, the distance measurement value is obtained in the same manner as in the seventh embodiment.

  In the ninth embodiment, by increasing the step frequency, it is possible to reduce the leakage of the short-distance pulse reflected from the long-distance target, and to prevent the ranging accuracy from being deteriorated. FIG. 27 shows this situation. The gain characteristic of the receiver is generally a characteristic that passes up to a frequency wider than the passband width. When the step frequency is small, the leakage of the short-distance pulse reflected by the long-distance target as shown in (a). The embedding becomes larger. On the other hand, by increasing the step frequency, the leakage of the short-distance pulse reflected by the long-distance target can be reduced as shown in FIG.

Embodiment 10 FIG.
FIG. 28 is a diagram showing a configuration of a radar apparatus according to Embodiment 10 of the present invention. Reference numeral 38 denotes a near-far order type wide frequency step-interval synthetic band transmitter that transmits the short-distance pulse first by increasing the step frequency and shifting the transmission frequency. The other parts basically correspond to the corresponding parts of the seventh embodiment.

  Next, the operation will be described. According to the operation time chart of FIG. 29, the short-distance order type wide frequency step interval type synthetic band type transmitter 38 transmits in the order of short-distance pulse and long-distance pulse. The short-distance pulse and the long-distance pulse reflected by the target 4 are received by the transmission / reception antenna 3 and stored in the memory circuit 9- # 1 and the memory circuit 9- # 2, respectively. Thereafter, the distance measurement value is obtained in the same manner as in the seventh embodiment.

  In the tenth embodiment, by increasing the step frequency, it is possible to reduce the leakage of the long-distance pulse reflected by the target outside the observation distance range and to prevent the ranging accuracy from being deteriorated.

Embodiment 11 FIG.
FIG. 30 shows a configuration of a radar apparatus according to Embodiment 11 of the present invention. Reference numeral 39 denotes a wide frequency step interval type multi-frequency step ICW type transmitter that increases the step frequency to shift the transmission frequency. The other parts basically correspond to the corresponding parts of the eighth embodiment.

  Next, the operation will be described. A long-distance pulse is transmitted from a wide frequency step interval type multi-frequency step ICW type transmitter 39 according to the operation time chart of FIG. Here, it is assumed that the transmission frequency is shifted so that the frequency step interval is increased. The long-distance pulse reflected by the target 4 is received by the transmission / reception antenna 3, and thereafter, the distance measurement value is obtained in the same manner as in the eighth embodiment.

  In the eleventh embodiment, by increasing the step frequency, it is possible to reduce the leakage of the short-distance pulse reflected by the long-distance target and prevent the ranging accuracy from deteriorating.

Embodiment 12 FIG.
FIG. 31 is a diagram showing a configuration of a radar apparatus according to Embodiment 12 of the present invention. Reference numeral 40 denotes a near-far order type wide frequency step-interval multi-frequency step ICW transmitter that increases the step frequency and shifts the transmission frequency to transmit the short-distance pulse first. The other parts basically correspond to the corresponding parts of the eighth embodiment.

  Next, the operation will be described. In accordance with the operation time chart of FIG. 32, the short distance order type wide frequency step interval type multi frequency step ICW type transmitter 40 transmits the short distance pulses and the long distance pulses in this order. The short-distance pulse and the long-distance pulse reflected by the target 4 are received by the transmission / reception antenna 3 and stored in the memory circuit 9- # 1 and the memory circuit 9- # 2, respectively. Thereafter, the distance measurement value is obtained in the same manner as in the eighth embodiment.

  In the twelfth embodiment, by increasing the step frequency, it is possible to reduce the leakage of the long-distance pulse reflected from the target outside the observation distance range, and to prevent the ranging accuracy from being deteriorated.

  In each embodiment, the MUSIC method is used as a super-resolution processing method. However, instead of the MUSIC method, an ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) method, which can be expected to speed up the super-resolution processing, It is also possible to use a maximum likelihood estimation method or the like that can be expected to provide accurate ranging.

  Further, the present invention is not limited to the above-described embodiments, and it goes without saying that all possible combinations thereof are included.

  1 Synthetic Band Type Transmitter, 2 Circulator, 3 Transmitting / Receiving Antenna, 4 Target, 5 Mixer, 6 Receiver, 7 A / D Converter, 8 Changeover Switch, 9- # 1, 9- # 2 Memory Circuit, 10 Synthesis Band Type long distance target ranging means, 11 synthetic band type short distance target ranging means, 12- # 1 to 12- # N pulse compression means, 13 synthetic band type target detecting means, 14 super-resolution ranging means, 15 Correlation matrix generating means, 16 MUSIC eigenvector calculating means, 17 MUSIC processing means, 18 Near-far order type synthetic band type transmitter, 19 Multi-frequency step ICW type transmitter, 20 Multi-frequency step ICW type long-range target ranging means , 21 Multi-frequency step ICW type short-range target ranging means, 22- # 1 to 22- # N Pulse hit direction FFT unit, 23 Multi-frequency step ICW type target detecting means, 2 4- # 1-24-N Doppler correction means, 25 near-far sequence type multi-frequency step ICW type transmitter, 26 transmission order variable type composite band type transmitter, 27 switching judgment circuit, 28 transmission order variable type multi frequency step ICW transmitter, 30 perspective individual type combined band type transmitter, 31 combined band type long range target ranging means with sort function, 32 combined band type short range target ranging means with sort function, 33 sort means, 34 Perspective individual type multi-frequency step ICW type transmitter, 35 multi-frequency step ICW type distance measuring means with sort function, 36 multi-frequency step ICW type distance measuring means with sort function, 37 wide frequency step interval Type synthetic band type transmitter, 38 near-far sequence type wide frequency step interval type synthetic band type transmitter, 39 wide frequency step interval type multi frequency step ICW type transmitter, 0 near far ordinal wide frequency step interval type stepped multiple frequency ICW Transmitter.

Claims (25)

The short-distance pulse with low power and the long-distance pulse with high power are transmitted alternately while changing the transmission frequency, and the short-distance pulse and the long-distance pulse reflected by the target are passed through with different frequency band restrictions. A transmission / reception system to be output after
A ranging system for measuring the distance from the output of the transmission / reception system to the target;
A radar apparatus comprising:   The transmission / reception system alternately transmits a short-distance pulse having a pulse width determined by the reciprocal of the transmission bandwidth and a long-distance pulse subjected to code modulation in units of a chip width determined by the reciprocal of the transmission bandwidth. The radar apparatus according to claim 1.   The transmission / reception system transmits the short-distance pulse and the long-distance pulse at different frequencies, mixes at the short-distance pulse transmission frequency when the short-distance target is detected, and uses the long-distance pulse transmission frequency when the long-distance target is detected. The radar apparatus according to claim 1, wherein mixing is performed.   The transmission / reception system includes a synthetic band type transmitter that generates and transmits a short-distance pulse and a long-distance pulse and steps a transmission frequency when switching between the long-distance pulse and the short-distance pulse. The radar apparatus according to any one of claims 1 to 3.   The transmission / reception system includes a multi-frequency step ICW type transmitter that generates and transmits a short-distance pulse and a long-distance pulse and repeats a frequency sweep pattern when stepping the transmission frequency a plurality of times. The radar apparatus according to any one of claims 1 to 3. The transmission / reception system includes a transmitter having a transmission order variable type capable of generating and transmitting a short-distance pulse and a long-distance pulse and switching a transmission sequence of the long-distance pulse and the short-distance pulse,
The distance measurement system includes a switching determination circuit that determines a transmission order of pulses according to a pulse interference state based on an output of the transmission / reception system and feeds back to a transmitter.
The radar apparatus according to any one of claims 1 to 3, wherein the transmitter switches a transmission order of a long-distance pulse and a short-distance pulse according to feedback.   The transmission / reception system includes a near / far individual type combined band transmitter that generates and transmits a short-distance pulse and a long-distance pulse and steps the transmission frequency each time the long-distance pulse and the short-distance pulse are switched. The radar device according to any one of claims 1 to 3, wherein   The transmission / reception system generates and transmits a short-distance pulse and a long-distance pulse, and steps the transmission frequency every time switching between the long-distance pulse and the short-distance pulse, and the frequency at which the transmission frequency is stepped The radar apparatus according to any one of claims 1 to 3, further comprising a perspective individual type multi-frequency step ICW transmitter that repeats the sweep pattern a plurality of times.   Wide frequency that the transmission / reception system generates and transmits short-distance pulses and long-distance pulses and steps the transmission frequency with large frequency fluctuations when switching between long-distance pulses and short-distance pulses The radar apparatus according to any one of claims 1 to 3, further comprising a step-interval type synthetic band transmitter.   When the transmission / reception system generates and transmits a short-distance pulse and a long-distance pulse, and when switching between the long-distance pulse and the short-distance pulse, the transmission frequency is stepped with a large frequency fluctuation, and the transmission frequency is stepped. 4. The radar apparatus according to claim 1, further comprising a wide frequency step-interval multi-frequency step ICW transmitter that repeats a frequency sweep pattern of a plurality of times. 5. The transmission / reception system
Synthetic band type transmitter that transmits alternately in the order of long-distance pulses and short-distance pulses and generates transmission pulses by stepping the transmission frequency when switching from short-distance pulses to long-distance pulses, or short-distance A near-far order type synthetic band transmitter that alternately transmits in the order of pulses for long distance and pulses for long distance and generates transmission pulses by stepping the transmission frequency when switching from long distance pulses to short distance pulses ,
A circulator that switches between transmission and reception of radio waves,
A transmission / reception antenna that transmits and receives radio waves using transmission pulses; and
A mixer that mixes received and transmitted pulses;
A receiver for performing band detection and phase detection of the mixed received signal,
The ranging system is
An A / D converter that samples an analog signal from the receiver to generate a digital signal;
A changeover switch for switching the digital signal from the A / D converter between a short distance target process and a long distance target process;
A memory circuit for separately storing digital signals for short-distance targets and long-distance targets switched by the changeover switch;
A synthetic band type far-distance target ranging means for performing a ranging process assuming a long-distance target on the basis of a digital signal for the long-distance target, assuming pulse transmission / reception of the transmitter,
Synthetic-band type near-field target distance measurement means for performing distance measurement processing assuming the near-field target based on the transmission and reception of the transmitter pulse based on the short-range target digital signal
The radar device according to any one of claims 1 to 3, wherein Code modulation is applied to long-distance pulses at the transmitter,
Synthetic band type distance target distance measuring means,
Pulse compression means for compressing a long-distance pulse subjected to code modulation of a digital signal stored in a memory circuit to improve the S / N ratio;
Synthetic band type target detection means for performing target detection processing assuming pulse transmission and reception by a transmitter with respect to a pulse-compressed signal;
Super-resolution ranging means for measuring the target distance of the target detection processing result with a resolution higher than the range resolution;
The radar apparatus according to claim 11, comprising: Synthetic band type short-range target ranging means
Synthetic band type target detection means for performing target detection processing assuming pulse transmission / reception by a transmitter with respect to a short-distance pulse signal of a digital signal stored in a memory circuit;
Super-resolution ranging means for measuring the target distance of the target detection processing result with a resolution higher than the range resolution;
The radar apparatus according to claim 11, comprising: Super-resolution ranging means
A correlation matrix generating means for generating a correlation matrix representing a correlation between transmission frequencies of target distances of target detection processing results;
MUSIC eigenvector calculation means for calculating an eigenvector for performing MUSIC processing on the correlation matrix;
MUSIC processing means for performing MUSIC processing according to eigenvectors;
The radar apparatus according to claim 12 or 13, characterized by comprising: The transmission / reception system
Transmits alternately in the order of the long-distance pulse and short-distance pulse, and steps the transmission frequency when switching from the short-distance pulse to the long-distance pulse. Repeated multi-frequency step ICW transmitter, or alternately transmit in the order of short-distance pulse, long-distance pulse and step the transmission frequency when switching from long-distance pulse to short-distance pulse A near frequency sequence type multi-frequency step ICW transmitter that repeats a frequency sweep pattern multiple times when
A circulator that switches between transmission and reception of radio waves,
A transmission / reception antenna that transmits and receives radio waves using transmission pulses; and
A mixer that mixes received and transmitted pulses;
A receiver for performing band detection and phase detection of the mixed received signal,
The ranging system is
An A / D converter that samples an analog signal from the receiver to generate a digital signal;
A changeover switch for switching the digital signal from the A / D converter between a short distance target process and a long distance target process;
A memory circuit for separately storing digital signals for short-distance targets and long-distance targets switched by the changeover switch;
A multi-frequency step ICW type long-distance target ranging means for detecting and measuring a long-distance target signal in the Doppler frequency domain based on a long-distance target digital signal;
A multi-frequency step ICW type short-range target ranging means for detecting and measuring a short-range target signal in the Doppler frequency domain based on the short-range target digital signal;
including,
The radar device according to any one of claims 1 to 3, wherein Code modulation is applied to long-distance pulses at the transmitter,
Multi-frequency step ICW type long-distance target ranging means
Pulse compression means for compressing a long-distance pulse subjected to code modulation of a digital signal stored in a memory circuit to improve the S / N ratio;
A pulse hit direction FFT unit for obtaining a Doppler frequency from the phase change of the target signal with respect to the pulse hit direction based on the pulse-compressed long-distance pulse;
Multi-frequency step ICW type target detection means for performing target detection processing assuming pulse transmission and reception by a transmitter;
Doppler correction means for correcting the phase rotation of the target signal rotated by the Doppler of the target detection processing result;
Super-resolution ranging means for measuring the target distance of the target detection processing result corrected by Doppler with a resolution higher than the range resolution;
The radar apparatus according to claim 15, comprising: Multi-frequency step ICW type short-range target ranging means
A pulse hit direction FFT unit for obtaining a Doppler frequency from a phase change of a target signal with respect to a pulse hit direction based on a short distance pulse of a digital signal stored in a memory circuit;
Multi-frequency step ICW type target detection means for performing target detection processing assuming pulse transmission and reception by a transmitter;
Doppler correction means for correcting the phase rotation of the target signal rotated by the Doppler of the target detection processing result;
Super-resolution ranging means for measuring the target distance of the target detection processing result corrected by Doppler with a resolution higher than the range resolution;
The radar apparatus according to claim 15, wherein the radar apparatus includes: In a transmission / reception system, a synthetic band transmitter or a near-far order synthetic band transmitter can switch a long-distance pulse and a short-distance pulse to a desired order, and generates a transmission pulse by stepping the transmission frequency. Each consists of a variable transmission order type, a combined band type transmitter or a near-far order type combined band type transmitter,
Switching determination in which the ranging system determines the transmission order of the pulses according to the interference situation of the pulses based on the digital signals of the synthetic band type short range target ranging means and the synthetic band type long range target ranging means and feeds back to the transmitter Further comprising a circuit,
15. The transmission sequence variable type synthetic band type transmitter or near-far order type synthetic band type transmitter switches the transmission order of long-distance pulses and short-distance pulses according to feedback. The radar apparatus according to any one of the above. In the transmission / reception system, the multi-frequency step ICW transmitter or the near-far sequence type multi-frequency step ICW transmitter can switch the long-distance pulse and short-distance pulse to the desired order, step the transmission frequency, and transmit Each of the transmission order variable type that repeats the frequency sweep pattern when stepping the frequency a plurality of times, is composed of a multi-frequency step ICW type transmitter or a near-far order type multi-frequency step ICW type transmitter,
A switching determination circuit in which the ranging system determines the interference state of the pulse based on the digital signals of the multi-frequency step ICW type long-distance target ranging means and the multi-frequency step ICW type short-range target ranging means and feeds back to the transmitter Further including
The transmission order variable type multi-frequency step ICW type transmitter or near-far order type multi-frequency step ICW type transmitter switches the transmission order of long-distance pulses and short-distance pulses according to feedback. Item 18. The radar device according to any one of Items 15 to 17. In the transmission / reception system, the combined band type transmitter or the near / far order type combined band type transmitter generates a transmission pulse by stepping the transmission frequency every time the long distance pulse and the short distance pulse are switched. , Consisting of a synthetic band type transmitter or a near band order type synthetic band type transmitter,
In the ranging system, the synthetic band-type short-range target ranging means and the synthetic-band type long-range target ranging means arrange the digital signals for the short-range target and the long-range target in order from the lowest transmission frequency. It is composed of a synthetic band type short-range target ranging means with a sorting function and a synthetic band type long-distance target ranging means with a sorting function, each of which performs a ranging process after switching,
The radar apparatus according to claim 11. Code modulation is applied to long-distance pulses at the transmitter,
Synthetic band type long-distance target ranging means with sorting function
Pulse compression means for compressing a long-distance pulse subjected to code modulation of a digital signal stored in a memory circuit to improve the S / N ratio;
Synthetic band type target detection means for performing target detection processing assuming pulse transmission and reception by a transmitter with respect to a pulse-compressed signal;
Sort means for rearranging and outputting the signals of the target detection processing results in order from the lowest transmission frequency,
A super-resolution ranging means for measuring the target distance of the sorted target detection processing result with a resolution higher than the range resolution,
Synthetic band type short-range target ranging means with sorting function
Synthetic band type target detection means for performing target detection processing assuming pulse transmission / reception by a transmitter with respect to a short-distance pulse signal of a digital signal stored in a memory circuit;
Sort means for rearranging and outputting the signals of the target detection processing results in order from the lowest transmission frequency,
Super-resolution ranging means for measuring the target distance of the sorted target detection processing result with a resolution higher than the range resolution,
The radar apparatus according to claim 20. In a transmission / reception system, a multi-frequency step ICW transmitter or a near-far sequence multi-frequency step ICW transmitter generates a transmission pulse by stepping the transmission frequency each time a long-distance pulse and a short-distance pulse are switched. It consists of a multi-frequency step ICW transmitter of a perspective individual type or a multi-frequency step ICW transmitter of a near-far sequence type,
In a ranging system, a multi-frequency step ICW type short-range target ranging unit and a multi-frequency step ICW type long-distance target ranging unit transmit digital signals for short-distance targets and long-distance targets, respectively, with low transmission frequencies. A multi-frequency step ICW type short-range target ranging means with a sorting function and a multi-frequency step ICW type long-distance target ranging means with a sorting function, each of which performs a ranging process after rearrangement in order from the direction,
The radar apparatus according to claim 15. Code modulation is applied to long-distance pulses at the transmitter,
Multi-frequency step ICW type long distance target ranging means with sorting function
Pulse compression means for compressing a long-distance pulse subjected to code modulation of a digital signal stored in a memory circuit to improve the S / N ratio;
A pulse hit direction FFT unit for obtaining a Doppler frequency from the phase change of the target signal with respect to the pulse hit direction based on the pulse-compressed long-distance pulse;
Multi-frequency step ICW type target detection means for performing target detection processing assuming pulse transmission and reception by a transmitter;
Doppler correction means for correcting the phase rotation of the target signal rotated by the Doppler of the target detection processing result;
Sorting means for rearranging and outputting the signals of the target detection processing results corrected by Doppler in order from the lowest transmission frequency;
Super-resolution ranging means for measuring the target distance of the sorted Doppler-corrected target detection processing result with a resolution higher than the range resolution,
Multi-frequency step ICW type short-range target ranging means with sorting function
A pulse hit direction FFT unit for obtaining a Doppler frequency from a phase change of a target signal with respect to a pulse hit direction based on a short distance pulse of a digital signal stored in a memory circuit;
Multi-frequency step ICW type target detection means for performing target detection processing assuming pulse transmission and reception by a transmitter;
Doppler correction means for correcting the phase rotation of the target signal rotated by the Doppler of the target detection processing result;
Sorting means for rearranging and outputting the signals of the target detection processing results corrected by Doppler in order from the lowest transmission frequency;
Super-resolution ranging means for measuring the target distance of the sorted Doppler-corrected target detection processing result with a resolution higher than the range resolution,
The radar apparatus according to claim 22. The transmission / reception system
By transmitting alternately in the order of long-distance pulse and short-distance pulse, and switching from short-distance pulse to long-distance pulse, the frequency is switched between a frequency greater than a predetermined frequency and a small frequency. Wide frequency step-interval synthetic band transmitter that generates transmission pulses by stepping the transmission frequency with frequency fluctuations, or alternately transmitting in the order of short-distance pulses and long-distance pulses and short-distance pulses to short-distance distances A near-far order type wide frequency step interval type synthetic band type transmitter that generates a transmission pulse by stepping the transmission frequency with the large frequency fluctuation when switching to a pulse for use;
A circulator that switches between transmission and reception of radio waves,
A transmission / reception antenna that transmits and receives radio waves using transmission pulses; and
A mixer that mixes received and transmitted pulses;
A receiver for performing band detection and phase detection of the mixed received signal,
The ranging system is
An A / D converter that samples an analog signal from the receiver to generate a digital signal;
A changeover switch for switching the digital signal from the A / D converter between a short distance target process and a long distance target process;
A memory circuit for separately storing digital signals for short-distance targets and long-distance targets switched by the changeover switch;
Based on the digital signal for the long-distance target, a synthetic band with a sort function that performs the ranging process after rearranging the digital signal in order from the lowest transmission frequency, assuming the long-distance target assuming the transmission and reception of the pulse of the transmitter A long-range target distance measuring means,
Based on the digital signal for the short distance target, assuming the short distance target assuming the transmitter pulse transmission / reception, the composite band with sorting function to perform the ranging process after rearranging the digital signal in order from the lowest transmission frequency A distance measuring means for a near-type target,
The radar device according to any one of claims 1 to 3, wherein The transmission / reception system
By transmitting alternately in the order of long-distance pulse and short-distance pulse, and switching from short-distance pulse to long-distance pulse, the frequency is switched between a frequency greater than a predetermined frequency and a small frequency. Wide frequency step-interval multi-frequency step ICW transmitter that repeats the frequency sweep pattern when stepping the transmission frequency with frequency fluctuations and further stepping the transmission frequency, or the order of short-distance pulses and long-distance pulses Near-far order type that repeats the frequency sweep pattern when stepping the transmission frequency by stepping the transmission frequency with the large frequency fluctuation and further stepping the transmission frequency when switching from the long-distance pulse to the short-distance pulse Wide frequency step interval type multi-frequency step ICW transmitter,
A circulator that switches between transmission and reception of radio waves,
A transmission / reception antenna that transmits and receives radio waves using transmission pulses; and
A mixer that mixes received and transmitted pulses;
A receiver for performing band detection and phase detection of the mixed received signal,
The ranging system is
An A / D converter that samples an analog signal from the receiver to generate a digital signal;
A changeover switch for switching the digital signal from the A / D converter between a short distance target process and a long distance target process;
A memory circuit for separately storing digital signals for short-distance targets and long-distance targets switched by the changeover switch;
Multi-frequency step ICW type long distance with sort function that detects the distance target signal in the Doppler frequency domain based on the distance target digital signal, and then sorts the digital signal in order from the lowest transmission frequency. Target ranging means;
Multi-frequency step ICW type short distance with sorting function that detects the short distance target signal in the Doppler frequency domain based on the short distance target digital signal, and sorts the digital signal in order from the lowest transmission frequency. Target ranging means;
including,
The radar device according to any one of claims 1 to 3, wherein

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