Signal processing device, radar device, signal processing method, and signal processing program

Abstract

To suppress increase of cost and reduce the influence of a main bang.SOLUTION: The signal processor includes: a corrected value calculation unit for calculating a corrected value of the intensity for each distance from an antenna on the basis of a reception signal including a signal acquired by several times of sending or receiving through the antenna; and a suppression unit for suppressing a level showing reception data generated according to the reception signal on a distance-by-distance basis by using the corrected value for each distance.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a signal processing device, a radar device, a signal processing method, and a signal processing program. [Background technology]

[0002] In a device that transmits and receives radio waves, for example, when an antenna is shared for both transmission and reception, the transmitted signal is likely to sneak into the receiving side. As a technology related to the main bang, which is this sneaking signal, for example, Patent Document 1 (JP 2018-200176 A) discloses the following radar device. That is, the radar device includes a transmission trigger pulse generating unit that generates a transmission trigger pulse that determines the timing of emission of detection radio waves from the antenna, a sampling circuit that digitizes and captures the received signal obtained by receiving the reflected wave of the detection radio waves from a target at a predetermined sampling period, a buffer memory that temporarily stores multiple beams of received signal data sampled by the sampling circuit, an image memory that stores the received signal data transferred from the buffer memory as image data, an address generating circuit that generates address signals for writing / reading image data to / from the image memory, and a display such as a CRT that displays the image data read from the image memory. is configured so that the output period of the transmission trigger pulse differs for each transmission trigger pulse, and comprises an A / D converter that digitizes the reception signal obtained by the antenna at a predetermined sampling period in response to the transmission trigger pulse from the transmission trigger pulse generating unit, a main bang detection memory that stores the reception signal data for multiple beams digitized by the A / D converter, a main bang detection circuit that detects the main bang included in the reception signal data by taking a sweep correlation of the reception signal data for multiple beams stored in the main bang detection memory, and a start pulse generating unit that outputs a start pulse to the sampling circuit to start sampling in response to the main bang detected by the main bang detection circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-200176 Summary of the Invention [Problem to be solved by the invention]

[0004] To reduce the effect of the main bang, it is necessary to provide the radar device with a circuit that suppresses the received signal by specifying the timing and level, which increases costs. Furthermore, if the timing for suppressing the received signal is set incorrectly, the main bang may not be suppressed effectively, and the echo of a target located near the antenna may be erased.

[0005] The present invention has been made to solve the above-mentioned problems, and its object is to provide a signal processing device, a radar device, a signal processing method, and a signal processing program that can suppress an increase in cost and reduce the influence of main bang. [Means for solving the problem]

[0006] In order to solve the above problem, a signal processing device according to one aspect of the present invention includes a correction value calculation unit that calculates a correction value for intensity for each distance from the antenna based on a received signal including signals obtained by multiple transmissions and receptions via the antenna, and a suppression unit that uses the correction value for each distance to suppress, for each distance, the level indicated by received data generated based on the received signal. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress an increase in cost and reduce the influence of the main bang. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a diagram showing the configuration of a radar device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the configuration of a signal processing unit in the radar device according to the embodiment of the present invention. [Figure 3] FIG. 3 is a diagram for explaining the echo data correction process performed by the signal processing unit according to the embodiment of the present invention. [Figure 4] FIG. 4 is a diagram for explaining a state in which a missing signal occurs in the radar device according to the embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing an example of threshold setting by the signal processing unit according to the embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart defining an example of an operation procedure when the signal processing unit according to the embodiment of the present invention corrects echo data. [Figure 7] FIG. 7 is a diagram for explaining the processing content of each step in FIG. [Figure 8] FIG. 8 is a diagram for explaining the processing content of each step in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and their description will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any manner.

[0010] [Configuration and Operation] FIG. 1 is a diagram showing the configuration of a radar device according to an embodiment of the present invention.

[0011] 1, the radar device 301 is mounted on, for example, a ship, and includes a radar unit 201 and a display processing unit 202. The radar device 301 transmits a transmission signal to a detection target area, which is an area to be monitored, and receives a reflected signal of the transmission signal as a received signal. Then, based on the received signal, the radar device 301 performs processing to display, on the display processing unit 202, an echo image indicating the presence or absence of a target in the detection target area and the distance between the radar device 301 and the target.

[0012] The radar unit 201 includes a signal generating unit 110, a transmitting unit 120, a circulator 130, an antenna 140, a receiving unit 150, an A / D (Analog to Digital) converting unit 160, and a signal processing unit 101. The signal processing unit 101 is an example of a signal processing device.

[0013] The radar unit 201 outputs echo data indicating the detection results of targets in the detection area to the display processing unit 202. The antenna 140 rotates while emitting radio waves for each predetermined sweep period T. This allows the radar unit 201 to detect targets that exist in all directions around the ship or the like.

[0014] The radar unit 201 outputs echo data in a plurality of radio wave emission directions to the display processing unit 202 for each sweep period T. The radar unit 201 repeats a scanning operation in which the antenna 140 rotates 360 degrees to obtain echo data in all directions.

[0015] The display processing unit 202 performs processing to display an echo image of the detection target area on a display device based on the multiple echo data received from the radar unit 201.

[0016] The signal generating unit 110 in the radar unit 201 outputs, for example, a pulsed transmission trigger to the transmitting unit 120 during the sweep period T. The transmitting unit 120 generates the transmission radio wave using, for example, a magnetron or a solid-state element.

[0017] During the sweep period T, the transmitting unit 120 generates a transmission signal in the RF (Radio Frequency) band based on a transmission trigger received from the signal generating unit 110, and outputs the generated transmission signal in the RF band in the direction of radio wave radiation via the circulator 130 and the antenna 140.

[0018] The receiving unit 150 receives a signal including a reflected wave of the transmission signal transmitted from the antenna 140, i.e., a reflected signal resulting from the transmission signal being reflected by a target. In addition to the reflected signal, the received signal may include a signal resulting from part of the transmission signal being transmitted directly to the receiving unit 150 without passing through the antenna. In the signal processing unit 101, the antenna 140 rotates, thereby acquiring received signals from a plurality of directions.

[0019] More specifically, the receiving unit 150 receives, via the antenna 140 and the circulator 130, a reflected signal in the RF band, which is a signal obtained by reflecting a transmission signal transmitted from the antenna 140 by a target in the direction of radio wave emission. The receiving unit 150 detects and amplifies the received signal including the received reflected signal, and outputs the detected signal to the A / D conversion unit 160.

[0020] The A / D conversion unit 160 converts the received signal, which is an analog signal received from the receiving unit 150, into received data, which is a digital signal, by sampling it at a predetermined sampling frequency, and outputs it as echo data to the signal processing unit 101. Hereinafter, the operation during one sweep period T as described above will also be simply referred to as a "sweep."

[0021] The signal processing unit 101 performs a correction process (to be described later) on the multiple echo data received from the A / D conversion unit 160 over each sweep period T, and outputs the corrected echo data to the display processing unit 202 .

[0022] FIG. 2 is a diagram showing the configuration of a signal processing unit in the radar device according to the embodiment of the present invention.

[0023] 2, the signal processing unit 101 includes a storage unit 4 and a control unit 11. The control unit 11 includes an echo data acquisition unit 1, a correction value calculation unit 2, and a suppression unit 3. The control unit 11 is, for example, a processing circuitry.

[0024] The echo data acquisition unit 1 receives the echo data output from the A / D conversion unit 160 and stores it in the area of ​​the corresponding sweep period T in the storage unit 4.

[0025] The correction value calculation unit 2 calculates a correction value for the intensity of the received signal obtained by multiple transmissions and receptions via the antenna 140, i.e., the received signal received by the rotating antenna 140, for each distance D from the antenna 140 in the direction in which the transmitted signal transmitted from the antenna 140 is reflected.

[0026] Fig. 3 is a diagram for explaining the echo data correction process performed by the signal processing unit according to the embodiment of the present invention. In Fig. 3, the horizontal axis represents the direction of antenna 140, and the vertical axis represents the level of echo data. Fig. 3 shows echo data for one scan operation, i.e., one scan, at a certain distance from antenna 140.

[0027] Referring to Figure 3, while a peak of the target TE is obtained in the echo data ED1 for one scan, there is a missing echo in the echo data of sweeps SP2 and SP12 corresponding to two certain directions, where a sufficient level is not obtained.

[0028] 4 is a diagram for explaining a state in which a missing signal occurs in the radar device according to the embodiment of the present invention, in which the horizontal axis indicates the azimuth of the antenna 140 and the vertical axis indicates the level of the echo data.

[0029] For example, when a magnetron is used in the transmitter 120, the magnetron may occasionally fail to output a pulsed signal.

[0030] In FIG. 4, missing signals occur at the azimuths x° and y° of the antenna 140, and the levels of the echo data corresponding to the distances D11 to D15 from the antenna 140 are zero.

[0031] 2 again, in order to prevent the influence of missing data, the correction value calculation unit 2 performs statistical processing of the level indicated by the received data (hereinafter also referred to as "reception level") for each distance D, and calculates a correction value using the results of the statistical processing. More specifically, the correction value calculation unit 2 performs statistical processing of the reception levels in multiple directions including the target direction, which are part of all directions for one revolution of the antenna 140, for each distance D, and calculates a correction value for the target direction using the results of the statistical processing.

[0032] For example, in statistical processing, the correction value calculation unit 2 compares the level indicated by the target data, which is the target received data, with the levels indicated by other received data that were received at similar times, and replaces the level of the target data with a level higher than the target data. More specifically, in statistical processing, the correction value calculation unit 2 compares the level indicated by the target data, which is data received in the target direction, with the levels indicated by received data in other directions. That is, for each distance D, the correction value calculation unit 2 compares the level indicated by the target data, which is received data, with other levels indicated by received data whose direction of antenna 140 is different from that of the target data, replaces the level of the target data with other levels higher than the target data, and calculates a correction value using the replaced level.

[0033] Specifically, for example, the correction value calculation unit 2 determines the maximum value of the reception levels in the sweeps on either side of the target sweep, i.e., the sweeps in the previous and next directions, and the target sweep, as the reception level of the target sweep.

[0034] 3, the correction value calculation unit 2 replaces the reception level of the target sweep SP2 with the reception level of the sweep SP1, which is the maximum among the target sweep SP2 and the sweeps SP1 and SP3 on either side of the target sweep SP2. The correction value calculation unit 2 also replaces the reception level of the target sweep SP12 with the reception level of the sweep SP11, which is the maximum among the target sweep SP12 and the sweeps SP11 and SP13 on either side of the target sweep SP12.

[0035] As a result, echo data ED2 from which the influence of missing data has been removed can be obtained, as shown in FIG.

[0036] The correction value calculation unit 2 is not limited to a configuration in which the replacement is performed with the maximum value of three sweeps of the previous azimuth, the target azimuth, and the next azimuth, but may perform the replacement with either the previous azimuth or the next azimuth and the target azimuth, or may perform the replacement using the levels of azimuths that are two or more steps away. In other words, the "other received data that were received close in time" may be data that is not adjacent in time to the target data.

[0037] Then, the correction value calculation unit 2 calculates, for each distance D, the minimum value of the levels indicated by the received data obtained through multiple transmissions and receptions via the antenna 140, i.e., the levels indicated by the received data in all directions of the rotation of the antenna 140, and calculates the minimum value or a value based on the minimum value as the correction value.

[0038] For example, the correction value calculation unit 2 sets the minimum reception level of the echo data ED2 in all directions as the threshold value Th, which is the correction value.

[0039] The suppression unit 3 uses the correction value for each distance D to suppress, for each distance D, the level indicated by the reception data generated based on the reception signal.

[0040] Specifically, the suppression unit 3 generates echo data ED3 by subtracting a threshold value Th from the reception level of the echo data ED2 in all directions, and outputs the echo data ED3 to the display processing unit 202.

[0041] This makes it possible to obtain echo data ED3 that retains the peak of the target TE present in a specific direction and eliminates the influence of missing data.

[0042] The suppression unit 3 is not limited to a configuration that performs a calculation to subtract the threshold value Th from the level of the echo data ED2, but may be configured to perform another calculation using the threshold value Th instead of or in addition to the calculation to suppress the level of the echo data ED2. Furthermore, the suppression unit 3 may be configured to perform a calculation to subtract the threshold value Th from the level of the echo data ED1 instead of the echo data ED2, and output the result to the display processing unit 202.

[0043] 5 is a diagram showing an example of threshold setting by the signal processing unit according to the embodiment of the present invention, in which the horizontal axis indicates the distance from antenna 140 and the vertical axis indicates the level of echo data.

[0044] The signal processing unit 101 performs the processing shown in FIG. 3 for each distance from the antenna 140, for example, for each sample of the digital signal from the A / D conversion unit 160.

[0045] This makes it possible to set the threshold value Th, i.e., the correction value, according to the echo data at each distance. Specifically, referring to Fig. 5, at distances D5 to D7 where the peaks of targets TE1 to TE3 exist, threshold values ​​Th5 to Th7 are set lower than the peaks so as not to eliminate the peaks, and threshold values ​​Th1 to Th7 capable of suppressing the main bang can be set at each distance D1 to D7. Furthermore, at distances D3 and D4, threshold values ​​Th3 and Th4 can be set respectively so as to eliminate peaks other than those of targets due to characteristics specific to the device or circuit.

[0046] In other words, since targets such as ships exist only in specific directions, by setting the minimum value of the reception level for one scan as the threshold value Th, it is possible to suppress the main bang and other noise components without eliminating the peak due to the target TE.

[0047] Furthermore, the level of the main bang will be a different value depending on the distance, such as distances D1 to D4. Therefore, by calculating and correcting the threshold value Th for each distance, the main bang can be effectively suppressed.

[0048] [Operation flow] A radar device according to an embodiment of the present invention includes a computer including a memory, and a processing unit such as a CPU in the computer reads from the memory and executes a program including some or all of the steps in the following flowcharts and sequences. This program can be installed externally. This program is distributed in a state stored on a recording medium or via a communication line.

[0049] Fig. 6 is a flowchart showing an example of an operation procedure when the signal processing unit according to the embodiment of the present invention corrects echo data. Fig. 7 and Fig. 8 are diagrams for explaining the processing content of each step in Fig. 6.

[0050] 6 to 8, first, correction value calculation unit 2 acquires echo data of a target sweep from storage unit 4 (step S1).

[0051] Next, the correction value calculation unit 2 compares the reception level of the target sweep with the reception levels of the sweeps before and after the target sweep for each distance D from the antenna 140, and updates the echo data so that the maximum value of each reception level becomes the reception level of the target sweep. More specifically, the correction value calculation unit 2 saves the maximum value in an area in the storage unit 4 corresponding to the target sweep (step S2).

[0052] Next, the correction value calculation unit 2 saves the minimum value up to the target sweep in the target scan as the provisional threshold for each distance D from the antenna 140. More specifically, the correction value calculation unit 2 compares the saved maximum value with the provisional threshold in the storage unit 4 and saves the smaller value as a new provisional threshold. Here, when processing echo data in the first sweep of the target scan, the correction value calculation unit 2 saves the saved maximum value as the new provisional threshold. This resets the threshold for each scan, making it possible to obtain the minimum value for each scan as the threshold (step S3). Note that the threshold may be reset not for each scan, but for a predetermined number of scans.

[0053] Next, if processing for all sweeps in the target scan has not been completed (NO in step S4), the correction value calculation unit 2 acquires echo data for the next sweep, i.e., the next direction (step S1), and performs the processing described above (steps S2 and S3).

[0054] On the other hand, when processing for all sweeps in the target scan is completed (YES in step S4), the correction value calculation unit 2 fine-tunes the threshold by performing a predetermined calculation on the temporary threshold for each distance, and stores the adjusted value as the threshold Th in the storage unit 4. That is, the correction value calculation unit 2 finds the minimum value of the level indicated by the received data in all directions of rotation of the antenna 140 for each distance D, and calculates a value based on the minimum value as the correction value (step S5).

[0055] Next, the suppression unit 3 uses the correction value to suppress the level indicated by the received data from the scan next to the scan corresponding to the correction value onwards. More specifically, the suppression unit 3 uses the correction value, i.e., the threshold value Th stored in the storage unit 4, to suppress the level indicated by the received data obtained by the rotation of the antenna 140 from the scan next to the scan corresponding to the threshold value Th onwards.

[0056] For example, the suppression unit 3 corrects the echo data of the next scan using the stored threshold value Th. More specifically, the suppression unit 3 obtains the threshold value Th calculated from the echo data of the previous scan from the storage unit 4, and subtracts the threshold value Th from the echo data of the new scan to generate echo data from which the main bang has been removed, and outputs the echo data to the display processing unit 202.

[0057] In this way, in the signal processing unit 101, the correction value calculation unit 2 determines the threshold value Th corresponding to the new scan, and the suppression unit 3 corrects the echo data corresponding to the new scan in parallel (step S6).

[0058] The correction value calculation unit 2 may be configured not to generate echo data from which the influence of missing data has been removed (step S2).

[0059] The correction value calculation unit 2 may be configured to use the provisional threshold value as the threshold value Th without adjusting the provisional threshold value (step S5).

[0060] Furthermore, the suppression unit 3 is not limited to a configuration in which the threshold value Th determined using the echo data of the previous scan is subtracted from the echo data of the new scan (step S6), but may be a configuration in which the threshold value Th determined using the echo data of the scan two or more times before is subtracted from the echo data of the new scan.

[0061] Furthermore, the signal processing unit 101 is not limited to a configuration that performs the parallel processing (step S6) as described above, but may also be configured to determine a threshold value Th corresponding to a new scan by the correction value calculation unit 2, and then correct the echo data corresponding to the new scan by the suppression unit 3 using the determined threshold value Th.

[0062] Furthermore, the signal processing unit 101 is not limited to radar devices, but can also be installed in sonars, fish finders, and other devices that have transducers (antennas) that transmit and receive ultrasonic waves, and can perform the correction processing described above. That is, the configuration is not limited to one in which the antenna rotates, and the correction value calculation unit 2 may be configured to calculate a correction value for intensity for each distance from the antenna based on received signals that include signals acquired through multiple transmissions and receptions via a rotating or non-rotating antenna. Note that, as in sonar, the antenna and the transmitting unit 120 may be the same, and a circulator may not be used.

[0063] In order to reduce the influence of the main bang, for example, it is necessary to provide the radar device with a circuit that suppresses the received signal in an analog stage by specifying the timing and level, which increases costs such as the cost of parts, circuit area, and parts management expenses. Also, if the timing for suppressing the received signal is set incorrectly, the main bang may not be suppressed effectively, and the echo of a target object located near the antenna may be erased.

[0064] In contrast, in the signal processing unit according to the embodiment of the present invention, the correction value calculation unit 2 calculates a correction value for the intensity for each distance from the antenna based on a received signal including signals acquired through multiple transmissions and receptions via the antenna. Then, the suppression unit 3 uses the correction value for each distance D to suppress, for each distance D, the level indicated by the received data generated based on the received signal.

[0065] In this way, by calculating a correction value for the strength of the received signal for each distance from the antenna and suppressing the level indicated by the received data for each distance, it is possible to eliminate the need for a circuit that specifies the timing and level to suppress the received signal in an analog stage, thereby reducing costs.In addition, it is easy to set the timing for suppressing the received signal, i.e., the distance from the antenna, so that the main bang can be effectively suppressed and the echo of a target object located near the antenna is not canceled out.Furthermore, since different levels of suppression can be performed for each distance, more ideal suppression results can be obtained.

[0066] Therefore, in the signal processing unit according to the embodiment of the present invention, it is possible to suppress an increase in cost and reduce the influence of the main bang.

[0067] Furthermore, in the signal processing unit according to the embodiment of the present invention, the correction value calculation unit 2 performs statistical processing on the level indicated by the received data for each distance D, and calculates a correction value using the results of the statistical processing.

[0068] This configuration prevents an incorrect threshold from being set due to a missing signal, which occurs when the transmitter 120 fails to output a pulsed signal and the echo data of the transmitted wave does not obtain a sufficient reception level in some directions of the antenna 140.

[0069] Furthermore, in the signal processing unit according to the embodiment of the present invention, the correction value calculation unit 2 compares the level indicated by the target data, which is the target received data, with the levels indicated by other received data that were received at similar times during statistical processing, replaces the level of the target data with a level greater than the target data, and calculates a correction value using the replaced level.

[0070] With this configuration, it is possible to prevent an incorrect threshold value from being set due to a missing signal by a simple process of comparing the reception levels in other directions and replacing them.

[0071] Furthermore, in the signal processing unit according to the embodiment of the present invention, the correction value calculation unit 2 calculates, for each distance D, the minimum value of the levels indicated by the received data obtained by multiple transmissions and receptions via the antenna 140, for example, the levels indicated by the received data in all directions of the rotation of the antenna 140, and calculates the minimum value or a value based on the minimum value as the correction value.

[0072] In this way, by configuring the system to select the minimum value of the reception level for one scan, i.e., one rotation of antenna 140, for each distance and set it as the threshold value, even if the target distance for suppressing the main bang is set beyond the range of the main bang, the lower limit of the noise level becomes the threshold value at distances where the main bang does not occur, and the target peak is hardly suppressed.

[0073] That is, in a configuration that includes a circuit that suppresses the received signal in an analog stage as described above, it is necessary to set the distance range for suppressing the reception level so as not to eliminate the echo of targets near the antenna 140. In contrast, with the configuration described above, the target peak does not disappear even if the suppression distance is extended, making it easier to set the distance. In other words, main bang suppression processing can be performed over a longer distance, resulting in more ideal suppression results.

[0074] Furthermore, in a configuration in which a circuit is provided that suppresses the received signal in an analog stage by specifying the timing and level, a certain level threshold is subtracted from the received signal in the range to be suppressed, so that the certain level threshold is also subtracted from the range in which the main bang remains at a low level.

[0075] In contrast, by using the minimum value in all directions at each distance as the subtraction value, it is possible to set an optimal threshold value according to the level in the low level range described above and subtract it, thereby preventing the reception level from being suppressed more than necessary and more reliably retaining the target peak in that range.

[0076] Furthermore, in the signal processing unit according to the embodiment of the present invention, the suppressing unit 3 uses the correction value to suppress the level indicated by the received data from the scan next to the scan corresponding to the correction value onwards.

[0077] With this configuration, the echo data obtained by a new scan can be corrected in parallel with the process of updating the correction values ​​using the echo data, so that the latest corrected echo data can be generated more quickly and the echo image can be displayed, etc.

[0078] In the signal processing unit according to the embodiment of the present invention, the received signal includes a signal that is a reflection of a transmission signal transmitted from antenna 140 and received by antenna 140 .

[0079] With this configuration, in a device where radio waves are transmitted and received via a common antenna and main bangs are likely to occur, a correction value for the strength of the received signal can be calculated for each distance from the antenna, and the level indicated by the received data can be suppressed for each distance, thereby preventing increases in costs and reducing the effects of main bangs.

[0080] In addition, in the signal processing method according to the embodiment of the present invention, first, a correction value for the intensity is calculated for each distance from the antenna based on a received signal including signals acquired through multiple transmissions and receptions via the antenna, and then, the correction value for each distance D is used to suppress the level indicated by the received data generated based on the received signal for each distance D.

[0081] In this way, by calculating a correction value for the strength of the received signal for each distance from the antenna and suppressing the level indicated by the received data for each distance, it is possible to eliminate the need for a circuit that specifies the timing and level to suppress the received signal in an analog stage, thereby reducing costs.In addition, it is easy to set the timing for suppressing the received signal, i.e., the distance from the antenna, so that the main bang can be effectively suppressed and the echo of a target object located near the antenna is not canceled out.Furthermore, since different levels of suppression can be performed for each distance, more ideal suppression results can be obtained.

[0082] Therefore, the signal processing method according to the embodiment of the present invention can suppress an increase in cost and reduce the influence of the main bang.

[0083] The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0084] 1. Echo data acquisition unit 2. Correction value calculation section 3. Repressor 4 Storage section 11 Control section 101 Signal processing section 201 Radar Section 202 Display processing unit 301 Radar equipment

Claims

1. a correction value calculation unit that calculates a correction value for the intensity for each distance from the antenna based on a received signal including signals acquired through multiple transmissions and receptions via the antenna; a suppression unit that suppresses, for each distance, a level indicated by reception data generated based on the reception signal, using the correction value for each distance; the correction value calculation unit compares, for each distance, a level indicated by target data that is the target received data with a level indicated by other received data that were received at close times, generates an intermediate processing signal in which the level of the target data is replaced with a level higher than that of the target data, obtains, for each distance, a minimum value of the levels indicated by the intermediate processing signal in all directions obtained by the multiple transmissions and receptions, and generates a threshold value calculated as the correction value from the minimum value or a value based on the minimum value; The suppression unit suppresses a level indicated by the received data for each distance using the threshold value.

2. The signal processing device described in Claim 1, wherein the correction value calculation unit saves the minimum value up to the intermediate processed signal in the target direction in the target scan as a provisional threshold for each distance, and when processing for all directions in the target scan is completed, saves the provisional threshold or a value obtained by performing a predetermined calculation on the provisional threshold as the threshold for each distance.

3. 3. The signal processing device according to claim 1, wherein the suppression unit uses the correction value to suppress a level indicated by the received data from a scan subsequent to the scan corresponding to the correction value.

4. The signal processing device according to claim 1 , wherein the antenna rotates to acquire the received signals from a plurality of directions.

5. A signal processing device according to any one of claims 1 to 4; The antenna; a transmitter that transmits a transmission signal via the antenna; a receiving unit that receives the received signal including a reflected wave of the transmitted signal; an A / D converter that converts the received signal into a digital signal and outputs the digital signal to the correction value calculator.

6. A signal processing method in a signal processing device, comprising: calculating a correction value for the intensity for each distance from the antenna based on a received signal including signals acquired through multiple transmissions and receptions via the antenna; suppressing, for each distance, a level indicated by reception data generated based on the reception signal using the correction value for each distance; In the signal processing method, For each distance, a level indicated by target data, which is the target received data, is compared with a level indicated by other received data received at close times, and an intermediate processed signal is generated by replacing the level of the target data with a level higher than that of the target data; for each distance, a minimum value of the level indicated by the intermediate processed signal in all directions obtained by the multiple transmissions and receptions is obtained; and a threshold value is generated by calculating the minimum value or a value based on the minimum value as the correction value; A signal processing method for suppressing a level indicated by the received data for each distance using the threshold value.

7. A signal processing program used in a signal processing device, A process of calculating a correction value for the intensity for each distance from the antenna based on a received signal including signals acquired through multiple transmissions and receptions via the antenna; and suppressing, for each distance, a level indicated by reception data generated based on the reception signal, using the correction value for each distance. It is a program for In the process of calculating the correction value, for each distance, a level indicated by target data, which is the target received data, is compared with a level indicated by other received data that were received at close times, and an intermediate processed signal is generated in which the level of the target data is replaced with a level higher than that of the target data; for each distance, a minimum value of the levels indicated by the intermediate processed signal in all directions obtained by the multiple transmissions and receptions is found; and a threshold value is generated in which the minimum value or a value based on the minimum value is calculated as the correction value; a signal processing program for suppressing a level indicated by the received data for each distance using the threshold value in the suppressing process;

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