JP6398637B2 - Radar signal processing device - Google Patents

Description

  The present invention relates to a radar signal processing apparatus.

  In a conventional LPRF (Low Pulse Repetition Frequency) radar, chirp pulse compression is performed to extend the detection distance. As one of the signal processing methods for chirp pulse compression, a V-chirp method for estimating the target relative speed from the distance measurement results of up-chirp and down-chirp when the relative speed to the target is other than 0 is used. In the V-chirp method, a pulse modulated in up-chirp and down-chirp is transmitted to the target, and the distance from each signal level measured from the pulse of the received signal reflected by the target is used as a peak. The relative distance and the relative speed can be calculated approximately (see, for example, Patent Document 1).

JP 2012-167948 A

  In the conventional V-chirp system, there is a problem that, in a clutter environment, the peak of the signal level is covered with the clutter signal and the target cannot be detected. In order to suppress this clutter signal, Patent Document 1 applies up-chirp and down-chirp modulation to the horizontally and vertically polarized transmission pulses, receives the reflected wave from the target, and polarizes the received signal. Polarization signal processing using a wave notch filter is performed. However, since several frames are required to obtain data necessary for polarization signal processing, there is a problem that the output rate when the detection target is adjacent is low.

  The present invention has been made in order to solve such problems. Even when polarization signal processing is used as a clutter suppression measure, high-precision distance measurement and speed measurement can be performed without reducing the output rate. Objective.

  A radar signal processing apparatus according to the present invention includes a horizontal polarization transmitter that transmits a horizontally polarized signal subjected to up-chirp modulation whose frequency increases and changes, and a reflection that is transmitted from the horizontal polarization transmitter and reflected by a target. A polarization receiving unit that receives vertical polarization and horizontal polarization of a wave, and an analog signal that is received by the polarization receiving unit and that converts an analog signal into polarization transmission or reception data of a digital signal A conversion unit; a feature amount extraction unit that converts the signal level between each polarization reception signal from the input digital signal after being converted into a digital signal by the A / D conversion unit; Based on a feature amount memory unit that holds the polarization feature amount output from the amount extraction unit, and when the target is a short distance, based on the digital signal of the A / D conversion unit and the polarization feature amount held in advance in the feature amount memory unit To generate a pseudo digital signal. When the target is a long distance, the correction processing unit that outputs the digital signal input from the A / D conversion unit, and the polarization transmission or polarization for each range bin in the digital signal or the pseudo digital signal input from the correction processing unit A data buffering unit that holds received data, a polarization component analysis unit that estimates a covariance matrix of clutter from polarization transmission or polarization reception data for each range bin held in the data buffering unit, and a data buffer A polarization notch filter unit that removes clutter components from the received signal as a digital signal or pseudo digital signal input to the ring unit by polarization signal processing, and pulsed the received signal after polarization signal processing by the polarization notch filter unit Pulse compression unit to be compressed, and received signal during up-chirp after pulse compression by the pulse compression unit Ranging unit for determining the distance at which the signal level measured from the pulse reaches a peak, vertical polarization transmitting unit for transmitting a vertically polarized signal modulated by down-chirp whose frequency changes downward, and vertical polarization transmitting unit The polarization receiver that receives the vertical and horizontal polarizations of the reflected wave transmitted from the target and reflected by the target, and the analog signal received by the polarization receiver for polarization transmission or polarization of a digital signal. A / D converter for converting to wave reception data and a digital signal converted by the A / D converter, and the signal level difference between each polarization reception signal is extracted from the input digital signal, and polarization feature quantity A feature quantity extraction unit that outputs the feature value, a feature quantity memory unit that holds the polarization feature quantity output from the feature quantity extraction unit, and a digital signal and a feature quantity memory unit of the A / D conversion unit when the target is a short distance Based on the polarization features stored in Next, a pseudo digital signal is generated, and when the target is a long distance, a correction processing unit that outputs the digital signal input from the A / D conversion unit, and each range bin in the digital signal or pseudo digital signal input from the correction processing unit Data buffering unit that holds the data of polarization transmission or reception of polarization and polarization that estimates the covariance matrix of the clutter from the data of polarization transmission or reception for each range bin held in the data buffering unit A component analysis unit, a polarization notch filter unit that removes clutter components from the received signal as a digital signal or pseudo-digital signal input to the data buffering unit by polarization signal processing, and a polarization signal by the polarization notch filter unit A pulse compression unit that performs pulse compression on the received signal after processing, and after pulse compression by the pulse compression unit A distance measuring unit for obtaining a distance at which the signal level measured from the pulse of the received signal at the time of unchirping reaches a peak, and a signal level measured from the pulse of the received signal respectively obtained by the distance measuring unit and the distance measuring unit are A distance measuring and measuring unit that approximately obtains a target relative distance and a relative speed based on a peak distance is provided.

  According to the present invention, according to the distance to the detection target, the polarization signal processing effective for suppressing the clutter signal is properly used in the V-chirp method, so that even when the target is close, the output rate is not lowered. High-precision distance measurement and speed measurement are possible.

1 is a diagram illustrating a configuration of a radar signal processing device according to Embodiment 1. FIG. It is a figure which shows the polarization signal processing operation in case the target by Embodiment 1 exists in a long distance. It is a figure which shows the polarization signal processing operation in case the target by Embodiment 1 exists in a short distance.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a radar signal processing apparatus according to Embodiment 1 of the present invention. In the figure, the radar signal processing apparatus according to the first embodiment includes a horizontal polarization transmission unit 101, a polarization reception unit 102, an A / D conversion unit 103, a feature amount extraction unit 104, a feature amount memory unit 105, and a correction processing unit 106. , Data buffering section 107, polarization component analysis section 108, polarization notch filter section 109, pulse compression section 110, distance measurement section 111, vertical polarization transmission section 121, polarization reception section 122, A / D conversion section 123 , Feature amount extraction unit 124, feature amount memory unit 125, correction processing unit 126, data buffering unit 127, polarization component analysis unit 128, polarization notch filter unit 129, pulse compression unit 130, distance measurement unit 131, distance measurement A speed measuring unit 112 is provided.

  The horizontally polarized wave transmission unit 101 transmits a horizontally polarized signal subjected to up-chirp modulation whose frequency increases and changes. The polarization receiving unit 102 receives the reflected wave from the target transmitted from the horizontal polarization transmitting unit 101 in the vertical polarization reception and the horizontal polarization reception. The A / D converter 103 samples the analog signal received by the polarization receiver 102, converts it to a digital signal, and outputs it. The feature quantity extraction unit 104 is converted into a digital signal by the A / D conversion unit 103, extracts a signal level difference between each polarization reception signal from the input digital signal, and outputs it as a polarization feature quantity. The feature amount memory unit 105 holds the polarization feature amount output from the feature amount extraction unit 104.

The operation of the feature amount memory unit 105 and the correction processing unit 106 differs depending on the distance from the target. For the distance to the target, an approximate distance is input in advance from an external device. When the approximate distance is equal to or greater than a predetermined threshold, it is determined that the distance from the target is far. It is judged that the distance is near.
Note that the distance to the target may be determined by comparing the distance measured at the previous measurement time in the radar signal processing device with a predetermined threshold.

The feature amount memory unit 105 outputs the polarization feature amount held in advance to the correction processing unit 106 when the target is a short distance.
When the target is a long distance, the correction processing unit 106 outputs the digital signal input from the A / D conversion unit 103 to the data buffering unit 107.
When the target is a short distance, the correction processing unit 106 uses the digital signal input from the A / D conversion unit 103 and the polarization feature value held in the feature value memory unit 105 to deviate from the input digital signal. A pseudo digital signal on which a waveform indicating a wave feature amount is superimposed is estimated and generated. The generated pseudo digital signal is output to the data buffering unit 107.

  The data buffering unit 107 holds polarization transmission / polarization reception data for each range bin in the input digital signal or pseudo digital signal. The polarization component analysis unit 108 estimates the clutter covariance matrix from the polarization transmission and polarization reception data for each range bin held in the data buffering unit 107. The polarization notch filter unit 109 constitutes a polarization notch filter, and removes clutter components from the received signal as a digital signal or pseudo digital signal input to the data buffering unit 107 by polarization signal processing. The pulse compression unit 110 pulse-compresses the received signal after the polarization signal processing by the polarization notch filter unit 109. The distance measuring unit 111 obtains a distance at which the signal level measured from the pulse of the received signal reaches a peak at the time of up-chirping after the pulse compression by the pulse compression unit 110.

  Further, the vertical polarization transmission unit 121 transmits a vertical polarization signal subjected to down-chirp modulation whose frequency changes downward. The polarization receiving unit 122 receives the reflected wave from the target transmitted from the vertical polarization transmitting unit 121 in the vertical polarization reception and the horizontal polarization reception. The A / D converter 123 samples the analog signal received by the polarization receiver 122, converts it to a digital signal, and outputs it. The feature amount extraction unit 124 converts the signal level between the polarization reception signals from the input digital signal, which is converted into a digital signal by the A / D conversion unit 123, and outputs it as a polarization feature amount. The feature amount memory unit 125 holds the polarization feature amount output from the feature amount extraction unit 124.

The feature amount memory unit 125 and the correction processing unit 126 have different operations depending on the distance from the target. For the distance to the target, an approximate distance is input in advance from an external device. When the approximate distance is equal to or greater than a predetermined threshold, it is determined that the distance from the target is far. It is judged that the distance is near.
Note that the distance to the target may be determined by comparing the distance measured at the previous measurement time in the radar signal processing device with a predetermined threshold.

The feature amount memory unit 125 outputs the polarization feature amount held in advance to the correction processing unit 126 when the target is a short distance.
When the target is a long distance, the correction processing unit 126 outputs the digital signal input from the A / D conversion unit 123 to the data buffering unit 127.
When the target is a short distance, the correction processing unit 126 estimates the pseudo digital signal by using the digital signal input from the A / D conversion unit 123 and the polarization feature amount held in the feature amount memory unit 125. Generate. The generated pseudo digital signal is output to the data buffering unit 127.

  The data buffering unit 127 holds polarization transmission / polarization reception data for each range bin in the input digital signal or pseudo digital signal. The polarization component analysis unit 128 estimates the clutter covariance matrix from the polarization transmission and polarization reception data for each range bin held in the data buffering unit 127. The polarization notch filter unit 129 forms a polarization notch filter, and removes clutter components from the received signal as a digital signal or pseudo digital signal input to the data buffering unit 127 by polarization signal processing. The pulse compression unit 130 performs pulse compression on the received signal after the polarization signal processing by the polarization notch filter unit 129. The distance measuring unit 131 obtains a distance at which the signal level measured from the pulse of the received signal reaches a peak at the time of down chirp after the pulse compression by the pulse compression unit 130.

  The polarization receiving unit 122, the A / D conversion unit 123, the feature amount extraction unit 124, the feature amount memory unit 125, the correction processing unit 126, the data buffering unit 127, the polarization component analysis unit 128, and the polarization notch filter unit 129, the pulse compression unit 130, and the ranging unit 131 are a polarization receiving unit 102, an A / D conversion unit 103, a feature amount extraction unit 104, a feature amount memory unit 105, a correction processing unit 106, and a data buffering unit 107, respectively. A circuit similar to that of the polarization component analysis unit 108, the polarization notch filter unit 109, the pulse compression unit 110, and the distance measurement unit 111 is used.

  Ranging and measuring unit 112 approximates the target relative distance and relative speed based on the distances obtained by the ranging unit 111 and the ranging unit 131, respectively, at which the signal level measured from the pulse of the received signal peaks. Ask for.

Next, the operation of the first embodiment will be described.
Since the operation principle of the V-chirp method to which the polarization signal processing is applied is described in Patent Document 1, it is omitted.

FIG. 2 is a diagram illustrating an operation when the target according to the first embodiment is located at a long distance.
First, the operation when the target is at a long distance will be described. As shown in FIG. 2, when the target is a long distance, horizontal polarization and vertical polarization are alternately transmitted in a time division manner. In the following, a signal that has been horizontally reflected from the target and received by horizontal polarization will be referred to as a reception signal HH, and a signal that has been received by vertical polarization will be referred to as a reception signal HV. Similarly, a signal obtained by reflecting a vertically polarized wave transmission signal at a target and receiving a horizontally polarized wave is called a received signal VH, and a signal received by a vertically polarized wave is called a received signal VV. In the polarization signal processing, polarization signal processing is performed by using these four received signals HH, HV, VH, and VV.

  The horizontally polarized wave transmission unit 101 transmits a horizontally polarized signal subjected to up-chirp modulation to the target. In addition, the vertical polarization transmission unit 121 transmits a horizontally polarized signal subjected to down-chirp modulation to the target. It is assumed that the horizontal polarization transmission unit 101 and the vertical polarization transmission unit 121 alternately transmit polarization signals in a time division manner.

  The polarization receiving unit 102 receives a horizontal reflected wave and a vertically polarized wave of a target reflected wave with respect to a horizontally polarized wave transmission signal. The polarization receiving unit 122 receives a horizontally reflected wave and a vertically polarized wave of a target reflected wave with respect to a vertically polarized wave transmission signal.

The A / D converter 103 samples the analog signals (received signal HH and received signal HV) received by polarization, A / D converts them into digital signals, generates a video signal, and corrects it with the feature quantity extractor 104. The data is output to the processing unit 106. Here, a video signal generated from the received signal HH is referred to as Shh, and a video signal generated from the received signal HV is referred to as Shv.
The A / D converter 123 samples the analog signals (received signal VH, received signal VV) received by polarization, A / D converts them into digital signals, generates a video signal, and corrects with the feature quantity extractor 124. The data is output to the processing unit 126. Here, a video signal generated from the received signal VH is referred to as Svh, and a video signal generated from the received signal VV is referred to as Svv.

  The feature amount extraction unit 104 extracts a signal level difference between each polarization reception signal from the input video signal, and outputs it as a polarization feature amount. The feature amount extraction unit 124 extracts a signal level difference between each polarization reception signal from the input video signal, and outputs it as a polarization feature amount. The feature quantity extraction unit 104 and the feature quantity extraction unit 124 share the input video signal.

  The video signals obtained in the previous frame are Svh (k-1) and Svv (k-1), and the video signals obtained in the current frame are Shv (k) and Shh (k). As a result, the polarization feature quantity obtained in the current frame is expressed by the following equations (1) and (2).

The feature amount memory unit 105 stores the input polarization feature amount in the memory when the target is a long distance. The feature amount memory unit 105 does not output to the correction processing unit 106 when the target is a long distance.
The feature amount memory unit 125 stores the input polarization feature amount in the memory when the target is a long distance. The feature amount memory unit 125 does not output to the correction processing unit 126 when the target is a long distance.

The correction processing unit 106 outputs the input video signal to the data buffering unit 107 when the target is a long distance.
The correction processing unit 126 outputs the input video signal to the data buffering unit 127 when the target is a long distance.

The data buffering unit 107 holds the video signal output from the correction processing unit 106 for each range bin.
The data buffering unit 127 holds the video signal output from the correction processing unit 126 for each range bin.

The polarization component analyzer 108 estimates the clutter covariance matrix using the video signal held in the range bin of the data buffering unit 107.
The polarization component analysis unit 128 estimates the clutter covariance matrix using the video signal held in the range bin of the data buffering unit 127.

The polarization notch filter unit 109 configures a polarization notch filter based on the clutter covariance matrix, and suppresses clutter of the received signal.
The polarization notch filter unit 129 forms a polarization notch filter based on the clutter covariance matrix, and suppresses clutter of the received signal.

The pulse compression unit 110 receives a video signal that has undergone polarization signal processing and performs pulse compression.
The pulse compression unit 130 receives a video signal that has undergone polarization signal processing, and performs pulse compression.

The distance measuring unit 111 obtains the peak movement distance of the correlation calculation from the initial relative distance to the target.
The distance measuring unit 131 obtains the peak movement distance of the correlation calculation from the initial relative distance to the target.

  The ranging / velocity measuring unit 112 uses the movement distance of the peak of the correlation calculation from the initial relative distance to the target obtained by the ranging unit 111 and the ranging unit 131 and the target relative speed at the time of up chirp after pulse compression. Approximately find the peak distance and peak distance during down-chirping.

  Thus, if up-chirp and down-chirp are transmitted in time division, the target relative distance and the relative speed can be calculated approximately using the measured peak distance during up-chirp and down-chirp.

  When the target is a long distance, polarization signal processing is possible by switching the polarization transmission signal to time division as described above, but horizontal polarization transmission and vertical polarization transmission are performed before the result is output. It is necessary to perform the transmission, and it takes time for two frames to transmit the horizontal polarization and the vertical polarization. Therefore, it is disadvantageous when the target is close.

  Therefore, when the target is close, the polarization signal processing applied when the target is at a long distance is switched to improve the output rate.

  FIG. 3 is a diagram illustrating an operation when the target according to the first embodiment is at a short distance. When the target is a short distance, the horizontal polarization and the vertical polarization are not transmitted alternately in time division, but one polarization transmission is stopped and only the other polarization signal is transmitted toward the target. FIG. 3 shows an example in which only horizontal polarization transmission is repeated. Hereinafter, although a method of performing horizontal polarization transmission will be described, a method of repeating vertical polarization transmission may be used.

  When the target is a short distance, the horizontal polarization transmitter 101 transmits a horizontally polarized signal subjected to up-chirp modulation to the target. However, the vertical polarization transmitter 121 does not transmit a horizontally polarized signal subjected to up-chirp modulation to the target. That is, when the target is a short distance, the transmission signal is not switched in time division, but the horizontal polarization transmission is repeated for each frame.

  The polarization receiving unit 102 receives a horizontally reflected wave and a vertically polarized wave of a target reflected wave for the horizontally polarized wave transmission signal from the horizontally polarized wave transmitting unit 101.

  The A / D conversion unit 103 samples the analog signals (received signal HH and received signal HV) received by polarization, A / D converts them into digital signals, generates video signals (Shh, Shv), and features The data is output to the extraction unit 104 and the correction processing unit 106.

  The feature amount extraction unit 104 extracts a signal level difference between each polarization reception signal from the input video signal, and outputs it as a polarization feature amount.

  When the target is a short distance, the feature amount memory unit 105 outputs the polarization feature amount stored in the memory to the correction processing unit 106.

  When the target is a short distance, the correction processing unit 106 outputs the video signal input from the A / D conversion unit 103 to the data buffering unit 107. Further, the correction processing unit 106 estimates a video signal (Svv, Svh) based on the polarization feature amount and the video signal input from the feature amount memory unit 105, and outputs them to the data buffering unit 107. The video signals of the current frame are represented as Shv (k) and Shh (k), and the estimated video signals (Svv (k) and Svh (k)) are expressed as the following equations (3) and (4).

  The subsequent operations are the same as when the target is a long distance, but the polarization transmission signal is not switched for each frame and the same polarization transmission is repeatedly performed. Therefore, the target relative distance and relative speed are set for each transmission frame. Can be calculated.

  Thus, by using properly the polarization signal processing applied to the V-chirp method according to the distance to the target, even when the target is close, high-precision distance measurement and speed measurement are performed without reducing the output rate. It becomes possible.

  As described above, the radar signal processing apparatus according to the first embodiment includes a horizontal polarization transmission unit 101 that transmits a horizontal polarization signal subjected to up-chirp modulation whose frequency increases and changes, and a horizontal polarization transmission unit 101. A polarization receiving unit 102 that receives the vertical polarization and horizontal polarization of the reflected wave that is transmitted and reflected by the target, and an analog signal that has been polarized and received by the polarization receiving unit 102, The A / D converter 103 that converts the data into polarization reception data, and the A / D converter 103 converts the signal to a digital signal. A feature amount extraction unit 104 that outputs as a wave feature amount, a feature amount memory unit 105 that holds a polarization feature amount output from the feature amount extraction unit 104, and an A / D conversion unit 103 when the target is a short distance Di A correction processing unit that generates a pseudo digital signal based on the total signal and the polarization feature amount previously stored in the feature amount memory unit 105 and outputs the digital signal input from the A / D conversion unit 103 when the target is a long distance 106, a data buffering unit 107 that holds polarized wave transmission or reception data for each range bin in the digital signal or pseudo digital signal input from the correction processing unit 106, and a range bin held in the data buffering unit 107 Polarization component analysis unit 108 that estimates the covariance matrix of clutter from polarization transmission data or polarization reception data for each polarization, and polarization from a received signal as a digital signal or pseudo digital signal input to data buffering unit 107 A polarization notch filter unit 109 for removing clutter components by signal processing; The signal level measured from the pulse of the received signal at the time of up-chirping after the pulse compression by the pulse compression unit 110 and the pulse compression unit 110 that performs pulse compression of the received signal after the polarization signal processing by the H filter unit 109 becomes a peak A distance measuring unit 111 for obtaining a distance, a vertical polarization transmitting unit 121 for transmitting a vertically polarized signal subjected to down-chirp modulation whose frequency changes downward, and a vertical polarization transmitting unit 121 are transmitted and reflected by a target. The polarization receiving unit 122 that receives the vertical polarization and the horizontal polarization of the reflected wave, and the analog signal received by the polarization receiving unit 122 is converted into polarization transmission data or polarization reception data of a digital signal. The A / D converter 123 and the A / D converter 123 convert it to a digital signal, and extract the signal level difference between each polarization reception signal from the input digital signal. , A feature amount extraction unit 124 that outputs as a polarization feature amount, a feature amount memory unit 125 that holds a polarization feature amount output from the feature amount extraction unit 124, and an A / D conversion unit when the target is a short distance The digital signal is generated based on the 123 digital signal and the polarization feature quantity held in the feature quantity memory unit 125, and when the target is a long distance, the digital signal input from the A / D conversion unit 123 is output. The data is stored in the processing unit 126, the data buffering unit 127 that holds polarization transmission or reception data for each range bin in the digital signal or pseudo digital signal input from the correction processing unit 126, and the data buffering unit 127. A polarization component analyzer 128 that estimates the covariance matrix of the clutter from polarization transmission data or polarization reception data for each range bin, A polarization notch filter unit 129 that removes clutter components from a received signal as a digital signal or a pseudo digital signal input to the falling unit 127 by polarization signal processing, and after polarization signal processing by the polarization notch filter unit 129 A pulse compression unit 130 for pulse-compressing the received signal; a distance measuring unit 131 for obtaining a distance at which the signal level measured from the pulse of the received signal peaks at the time of down-chirping after pulse compression by the pulse compression unit 130; Ranging and measuring unit 112 that approximately obtains the target relative distance and the relative velocity based on the distances at which the signal level measured from the pulse of the received signal peaks, obtained by the distance unit 111 and the ranging unit 131, respectively. It is characterized by comprising.

  As described above, the radar signal processing apparatus according to the first embodiment uses the polarization signal processing effective for suppressing the clutter signal in the V-chirp method according to the distance from the detection target, so that even when the targets are close to each other. High-precision distance measurement and speed measurement are possible without reducing the output rate.

Embodiment 2. FIG.
The configuration of the radar signal processing apparatus according to the second embodiment is shown in FIG. In the second embodiment, the horizontal polarization transmitter 141 transmits a horizontally polarized signal subjected to down-chirp modulation to the target. Further, the vertical polarization transmission unit 151 transmits a vertical polarization signal subjected to up-chirp modulation to the target. Other operations are the same as those in the first embodiment.

  The radar signal processing apparatus according to the second embodiment is transmitted from a horizontal polarization transmission unit 141 that transmits a horizontally polarized signal subjected to down-chirp modulation whose frequency changes downward, and a horizontal polarization transmission unit 141 that transmits the signal. Polarization receiving unit 102 that receives the vertical polarization and horizontal polarization of the reflected wave reflected, and the analog signal received by the polarization receiving unit 102 as polarization transmission data or polarization reception data of a digital signal A / D converter 103 that converts the signal into a digital signal by A / D converter 103, extracts a signal level difference between each polarization reception signal from the input digital signal, and outputs it as a polarization feature quantity Feature quantity extraction section 104, feature quantity memory section 105 that holds the polarization feature quantity output from the feature quantity extraction section 104, and digital signal and feature quantity of the A / D conversion section 103 when the target is a short distance A correction processing unit 106 that generates a pseudo digital signal based on the polarization feature quantity held in advance in the memory unit 105 and outputs the digital signal input from the A / D conversion unit 103 when the target is a long distance; Data buffering unit 107 that holds polarization transmission or polarization reception data for each range bin in the digital signal or pseudo digital signal input from unit 106, and polarization transmission for each range bin that is held in data buffering unit 107 Alternatively, the polarization component analysis unit 108 that estimates the covariance matrix of the clutter from the polarization reception data, and the clutter component by the polarization signal processing from the received signal as a digital signal or pseudo digital signal input to the data buffering unit 107 A polarization notch filter unit 109 for removing the polarization and a polarization notch filter unit 10 The pulse compression unit 110 that pulse-compresses the received signal after the polarization signal processing by, and the distance at which the signal level measured from the pulse of the received signal peaks when down-chirping after the pulse compression by the pulse compression unit 110 is obtained. Ranging unit 111, vertical polarization transmitting unit 151 that transmits a vertically polarized signal subjected to up-chirp modulation with increasing frequency, and a reflected wave that is transmitted from vertical polarization transmitting unit 151 and reflected by the target The polarization receiving unit 122 that receives the vertical polarization and the horizontal polarization, and the analog signal that is received by the polarization receiving unit 122 is converted into digital signal polarization transmission or polarization reception data. The signal is converted into a digital signal by the D conversion unit 123 and the A / D conversion unit 123, and a signal level difference between each polarization reception signal is extracted from the input digital signal, and is used as a polarization feature amount. The feature amount extraction unit 124 to output, the feature amount memory unit 125 to hold the polarization feature amount output from the feature amount extraction unit 124, and the digital signal and feature of the A / D conversion unit 123 when the target is a short distance A correction processing unit 126 that generates a pseudo digital signal based on the polarization feature quantity held in the quantity memory unit 125 and outputs the digital signal input from the A / D conversion unit 123 when the target is a long distance; A data buffering unit 127 that holds polarization transmission or reception data for each range bin in a digital signal or pseudo digital signal input from the processing unit 126, and a polarization for each range bin held in the data buffering unit 127 A polarization component analysis unit 128 that estimates a covariance matrix of clutter from transmission or polarization reception data, and a data buffering unit 12 A polarization notch filter unit 129 that removes clutter components from the received signal as a digital signal or pseudo-digital signal input to the signal by polarization signal processing, and pulses the received signal after polarization signal processing by the polarization notch filter unit 129 A pulse compression unit 130 that compresses, a distance measurement unit 131 that obtains a distance at which a signal level measured from a pulse of a received signal reaches a peak at the time of up-chirping after pulse compression by the pulse compression unit 130, and a distance measurement unit 111 A distance measuring and measuring unit 112 that approximately obtains a target relative distance and a relative speed based on the distance at which the signal level measured from the pulse of the received signal, which is obtained by the distance measuring unit 131, reaches a peak. It is characterized by that.

  As in the first embodiment, the output rate is lowered even when the target is close by using the polarization signal processing effective for suppressing the clutter signal in the V-chirp method according to the distance to the detection target. Without making it possible, highly accurate distance measurement and speed measurement are possible.

  101 horizontal polarization transmission unit, 102 polarization reception unit, 103 A / D conversion unit, 104 feature quantity extraction unit, 105 feature quantity memory unit, 106 correction processing unit, 107 data buffering unit, 108 polarization component analysis unit, 109 polarization notch filter unit, 110 pulse compression unit, 111 distance measurement unit, 121 vertical polarization transmission unit, 122 polarization reception unit, 123 A / D conversion unit, 124 feature quantity extraction unit, 125 feature quantity memory unit, 126 Correction processing section, 127 Data buffering section, 128 Polarization component analysis section, 129 Polarization notch filter section, 130 Pulse compression section, 131 Distance measurement section, 112 Distance measurement speed measurement section, 141 Horizontal polarization transmission section, 151 Vertical Polarization transmitter.

Claims (2)

A horizontally polarized wave transmission unit for transmitting a horizontally polarized signal subjected to up-chirp modulation in which the frequency rises and changes,
A first polarization receiving unit that receives the vertical polarization and horizontal polarization of the reflected wave transmitted from the horizontal polarization transmission unit and reflected by the target;
A first A / D converter that converts the analog signal received by the first polarization receiving unit into received data of vertical polarization and horizontal polarization of a digital signal;
A vertically polarized wave transmission unit that transmits a vertically polarized signal that is modulated with down-chirp whose frequency changes downward;
A second polarization receiving unit that receives the vertical polarization and horizontal polarization of the reflected wave transmitted from the vertical polarization transmission unit and reflected by the target;
A second A / D converter that converts the analog signal polarized by the second polarization receiver into data for polarization transmission or polarization reception of a digital signal;
From the digital signals converted by the first and second A / D converters, the difference between the horizontal polarization signal received after the horizontal polarization signal transmission and the vertical polarization signal received after the vertical polarization transmission, First and second feature quantity extraction units for calculating polarization feature quantities from the difference between the vertical polarization signal received after horizontal polarization transmission and the horizontal polarization signal received after vertical polarization transmission;
A first feature amount memory unit that holds a polarization feature amount output from the first feature amount extraction unit;
When the target is a short distance, a pseudo digital signal is generated based on the digital signal of the first A / D conversion unit and the polarization feature quantity previously held in the first feature quantity memory unit. A first correction processing unit that outputs a digital signal input from the first A / D conversion unit in the case of a long distance;
A first data buffering unit that holds polarization transmission or polarization reception data for each range bin in the digital signal or pseudo-digital signal input from the first correction processing unit;
A first polarization component analyzer that estimates a covariance matrix of a clutter from polarization transmission or polarization reception data for each range bin held in the first data buffering unit;
A first polarization notch filter unit that removes clutter components from a received signal as a digital signal or pseudo-digital signal input to the first data buffering unit by polarization signal processing;
A first pulse compression unit that pulse-compresses the received signal after polarization signal processing by the first polarization notch filter unit;
A first distance measuring unit for obtaining a distance at which a signal level measured from a pulse of a received signal reaches a peak at the time of up-chirping after pulse compression by the first pulse compressing unit;
A second feature amount memory unit that holds the polarization feature amount output from the second feature amount extraction unit;
When the target is a short distance, a pseudo digital signal is generated based on the digital signal of the second A / D conversion unit and the polarization feature quantity held in the second feature quantity memory unit. A second correction processing unit for outputting a digital signal input from the second A / D conversion unit in the case of a long distance;
A second data buffering unit that holds polarization transmission or polarization reception data for each range bin in the digital signal or pseudo-digital signal input from the second correction processing unit;
A second polarization component analysis unit that estimates a covariance matrix of clutter from polarization transmission or polarization reception data for each range bin held in the second data buffering unit;
A second polarization notch filter section that removes clutter components from a received signal as a digital signal or pseudo-digital signal input to the second data buffering section by polarization signal processing;
A second pulse compression unit that pulse-compresses the received signal after polarization signal processing by the second polarization notch filter unit;
A second distance measuring unit for obtaining a distance at which the signal level measured from the pulse of the received signal reaches a peak at the time of down chirp after the pulse compression by the second pulse compressing unit;
Approximate the target relative distance and relative speed based on the distance obtained by the first distance measuring section and the second distance measuring section, respectively, at which the signal level measured from the received signal pulse peaks. A radar signal processing device comprising a distance measuring and speed measuring unit to be obtained. A horizontally polarized wave transmission unit that transmits a horizontally polarized signal that is modulated with down-chirp whose frequency changes downward;
A first polarization receiving unit that receives the vertical polarization and horizontal polarization of the reflected wave transmitted from the horizontal polarization transmission unit and reflected by the target;
A first A / D converter that converts the analog signal received by the first polarization receiving unit into received data of vertical polarization and horizontal polarization of a digital signal;
A vertically polarized wave transmission unit that transmits a vertically polarized signal that has been modulated with an up-chirp whose frequency increases and changes;
A second polarization receiving unit that receives the vertical polarization and horizontal polarization of the reflected wave transmitted from the vertical polarization transmission unit and reflected by the target;
A second A / D converter that converts the analog signal polarized by the second polarization receiver into data for polarization transmission or polarization reception of a digital signal;
From the digital signals converted by the first and second A / D converters, the difference between the horizontal polarization signal received after the horizontal polarization signal transmission and the vertical polarization signal received after the vertical polarization transmission, First and second feature quantity extraction units for calculating polarization feature quantities from the difference between the vertical polarization signal received after horizontal polarization transmission and the horizontal polarization signal received after vertical polarization transmission;
A first feature amount memory unit that holds a polarization feature amount output from the first feature amount extraction unit;
When the target is a short distance, a pseudo digital signal is generated based on the digital signal of the first A / D conversion unit and the polarization feature quantity previously held in the first feature quantity memory unit. A first correction processing unit that outputs a digital signal input from the first A / D conversion unit in the case of a long distance;
A first data buffering unit that holds polarization transmission or polarization reception data for each range bin in the digital signal or pseudo-digital signal input from the first correction processing unit;
A first polarization component analyzer that estimates a covariance matrix of a clutter from polarization transmission or polarization reception data for each range bin held in the first data buffering unit;
A first polarization notch filter unit that removes clutter components from a received signal as a digital signal or pseudo-digital signal input to the first data buffering unit by polarization signal processing;
A first pulse compression unit that pulse-compresses the received signal after polarization signal processing by the first polarization notch filter unit;
A first distance measuring unit for obtaining a distance at which a signal level measured from a pulse of a received signal reaches a peak at the time of down chirp after pulse compression by the first pulse compressing unit;
A second feature amount memory unit that holds the polarization feature amount output from the second feature amount extraction unit;
When the target is a short distance, a pseudo digital signal is generated based on the digital signal of the second A / D conversion unit and the polarization feature quantity held in the second feature quantity memory unit. A second correction processing unit for outputting a digital signal input from the second A / D conversion unit in the case of a long distance;
A second data buffering unit that holds polarization transmission or polarization reception data for each range bin in the digital signal or pseudo-digital signal input from the second correction processing unit;
A second polarization component analysis unit that estimates a covariance matrix of clutter from polarization transmission or polarization reception data for each range bin held in the second data buffering unit;
A second polarization notch filter section that removes clutter components from a received signal as a digital signal or pseudo-digital signal input to the second data buffering section by polarization signal processing;
A second pulse compression unit that pulse-compresses the received signal after polarization signal processing by the second polarization notch filter unit;
A second distance measuring unit for obtaining a distance at which the signal level measured from the pulse of the received signal reaches a peak at the time of up-chirping after pulse compression by the second pulse compressing unit;
Approximate the target relative distance and relative speed based on the distance at which the signal level measured from the pulse of the received signal, obtained by the first distance measuring section and the second distance measuring section, respectively, peaks. A radar signal processing device comprising a distance measuring and speed measuring unit to be obtained.

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