Radar device and detection method

Abstract

To provide a radar device and a detection method capable of improving the accuracy of dirt detection, thereby improving the accuracy of distance calculation to a target.SOLUTION: The above-mentioned problem can be solved by a radar device (1) or the like in which a cover (3) is arranged on the front surface at a predetermined distance. The radar device (1) includes a transmission section (10) for transmitting a signal wave, a reception section (20) for receiving a reflected wave of the signal wave, a control processing section (30) having a first processing mode for processing the reflected wave from the predetermined distance to detect dirt on the cover (3), and a second processing mode for processing the reflected wave from a detection range of the radar except a range up to the predetermined distance to detect a target object. The control processing section (30) detects the dirt on the cover from the amplitude of the reflected wave reflected by the cover in a first processing mode, and detects the target object within the detection range of the radar by removing a component up to the predetermined distance from the reflected wave in the second processing mode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a radar device and a detection method, and more particularly to a radar device and a detection method for a mobile object that can detect a change in the state of a cover due to dirt or the like. [Background technology]

[0002] A radar device mounted on a moving object transmits a continuous wave (CW signal) signal and detects targets such as other moving objects based on the reflected wave. The radar device is installed inside a cover, such as a bumper, to protect it from external environmental factors such as mud and rain. The radar device transmits and receives reflected waves through the cover. Therefore, if dirt such as mud or scratches or dents that absorb or reflect radio waves adhere to the cover, detection performance will be reduced. Therefore, there is a need for a function that allows the radar device to detect dirt on the cover and notify the user.

[0003] Methods for detecting such dirt include those disclosed in Patent Document 1 and Patent Document 2. The method disclosed in Patent Document 1, which detects dirt by analyzing reflected waves from targets, has a problem in that the accuracy of dirt detection depends on the surrounding environment (type and number of targets). Furthermore, the method disclosed in Patent Document 2, which uses a specially structured cover provided with a metal reflector and detects dirt by calculating the deviation between the reception level of the reflected wave from the reflector and the reception level of the reflected wave from other sources, improves the accuracy of dirt detection, but requires a complex cover structure, resulting in high material and manufacturing costs. Furthermore, when using the bumper of a moving object as a cover, the bumper must be provided with a reflector in advance, which makes the method less versatile. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-237322 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-96136 Summary of the Invention [Problem to be solved by the invention]

[0005] The method of detecting dirt on a cover (bumper) by analyzing reflected waves from the cover can prevent a decrease in accuracy due to the surrounding environment, but because it is necessary to receive and analyze reflected waves including short-range reflected components, there is a risk that the accuracy of calculating the distance to the target will decrease. For this reason, in order to reduce the influence of short-range reflected components, it is necessary to verify the installation position to match the vehicle body at the design stage, and there is an issue that it is difficult to improve the accuracy of dirt detection and therefore the accuracy of calculating the distance to the target.

[0006] The present invention aims to provide a radar device and a detection method that can improve the accuracy of dirt detection without using a cover with a special structure, thereby improving the accuracy of distance calculation to a target. [Means for solving the problem]

[0007] The above problem can be solved by a radar device having a cover placed in front of it at a predetermined distance, the radar device comprising: a transmitter that transmits signal waves; a receiver that reflects the signal waves and receives the reflected waves; and a control processing unit having a first processing mode that processes the reflected waves from the predetermined distance to detect dirt on the cover, and a second processing mode that processes the reflected waves from the radar's detection range excluding the range up to the predetermined distance to detect targets, wherein in the first processing mode, the control processing unit detects dirt on the cover from the amplitude of the reflected waves reflected by the cover, and in the second processing mode, removes components from the reflected waves up to the predetermined distance to detect targets within the radar's detection range.

[0008] Here, "mobile object" includes not only passenger cars but also agricultural and construction vehicles, and does not necessarily have to be a single vehicle but also includes a collection of moving objects such as a tractor and trailer combination. Furthermore, a "cover" is a component that is installed in front of a radar device and has the function of protecting the radar device from the external environment, and includes the bumper of a mobile object. Furthermore, "dirt on the cover" includes not only dirt such as mud, rain, and snow, but also scratches and dents on the cover itself, which absorb or reflect radio waves and cause a decrease in detection performance.

[0009] The control processing unit preferably detects the presence or absence of dirt by comparing the amplitude of the reflected wave reflected by the cover with the amplitude of the reflected wave when the cover is clean. Furthermore, when the control processing unit detects the presence of dirt, it preferably determines the cause of the dirt from the magnitude of the time variation in the amplitude of the reflected wave reflected by the cover. Here, "cause of dirt" refers to causes that reduce the detection performance of the radar device, such as adhesions of mud, rain, snow, etc., or scratches or dents in the cover itself.

[0010] The control processing unit preferably detects the presence or absence of dirt and the degree of dirt by comparing the amplitude of the reflected wave reflected by the cover with the amplitude of the reflected wave when the cover is clean. Furthermore, the control processing unit preferably transmits a signal indicating that the cover needs to be cleaned when it detects that the degree of dirt exceeds a predetermined level, and transmits a signal indicating that the cover needs to be repaired when it detects that the degree of dirt exceeds the predetermined level despite receiving a signal indicating that cleaning has been completed.

[0011] Furthermore, it is desirable that the transmitting unit transmits a signal wave whose center frequency is changed to a plurality of frequencies with a predetermined frequency difference, and the control processing unit estimates the position of the target from the phase difference of beat signals corresponding to the plurality of frequencies contained in the reflected wave and the predetermined frequency difference.

[0012] The above problem can also be solved by a detection method including the steps of transmitting a signal wave by a radar device having a cover placed in front of it at a predetermined distance, reflecting the signal wave and receiving the reflected wave by the radar device, processing the reflected wave from the predetermined distance by the radar device to detect dirt on the cover, and removing components from the reflected wave up to the predetermined distance by the radar device to detect targets within the radar's detection range. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a radar device and a detection method that can improve the accuracy of detecting dirt, and thereby improve the accuracy of calculating the distance to a target. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic configuration diagram of a radar device according to the present invention; [Figure 2] 1 is a flowchart of a detection method according to the present invention. [Figure 3] 10 is a flowchart of a first processing mode. [Figure 4] FIG. 10 is an explanatory diagram of a second processing mode. [Figure 5] 10 is a flowchart of a second processing mode. [Figure 6] 10 is a flowchart of a target detection process. [Figure 7] 10 is a flowchart of a modified example of the detection method according to the present invention. [Figure 8] 10 is a flowchart of a modified example of the first processing mode. [Figure 9] 10 is a flowchart of a modified example of the second processing mode. DETAILED DESCRIPTION OF THE INVENTION

[0015] A schematic configuration diagram of a radar device 1 according to an embodiment of the present invention is shown in Fig. 1. The radar device 1 is mounted on a moving object, detects targets 4, and detects dirt on a cover 3 formed by the bumper of the moving object, transmits the detection results to a host device 2, and receives input from a user via the host device 2. The cover 3 is a concept that includes a radome that covers the front of the radar device 1 and a vehicle bumper. The cover 3 is placed in front of the radar device 1 at a predetermined distance.

[0016] The radar device 1 includes a transmitter 10, a receiver 20, and a control processor 30. The transmitter 10 includes a local oscillator 13, a modulator 12 connected to the local oscillator 13, and a transmitter antenna 11 connected to the modulator 12. The local oscillator 13 generates a continuous wave (CW signal) of a desired frequency and transmits it to the modulator 12 and the demodulators 231...23 of the receiver 20. n The modulator 12 pulse-modulates the CW signal supplied from the local oscillator 13 to generate a signal wave, and transmits the signal wave to the target 4 and the cover 3 via the transmitting antenna 11.

[0017] The receiving unit 20 includes a plurality of receiving antennas 211...21 n (n is a natural number) and each receiving antenna 211...21 n Amplification units 221...22 connected to n , each amplifier unit 221...22 n demodulation units 231...23 connected to n , and each demodulation unit 231...23 n A / D converter 241 connected to n Receiving antenna 211. n receives the reflected wave transmitted from the transmitting antenna 11 and reflected by the target 4 and the cover 3, and amplifies the received wave by the amplifiers 221...22. n The amplifier units 221, 222 n is amplified with a desired gain and demodulated by the demodulators 231...23 n The demodulation unit 231 outputs the demodulation signal to the demodulation unit 232. n is the amplifier 221...22 nThe received signal supplied from the A / D converter 241 is demodulated using the CW signal supplied from the local oscillator 13. n The A / D converter 241 outputs the signal to the A / D converter 242. n are demodulation units 231...23 n The demodulated signal is sampled at a predetermined cycle, converted into a digital signal, and supplied to the control processing unit 30.

[0018] The control processing unit 30 has a first processing mode in which reflected waves from a predetermined distance (the distance between the radar device 1 and the cover 3) are processed to detect dirt on the cover 3, and a second processing mode in which reflected waves from the radar detection range excluding the range up to the predetermined distance (the distance between the radar device 1 and the cover 3) are processed to detect the target 4. The control processing unit 30 includes a control unit 31, a processing unit 32, and a storage unit 33. The control unit 31 controls the pulse modulation of the modulation unit 12 and the amplification units 221...22. n The processing unit 32 controls the operation of each unit of the radar device 1, such as the gain of the A / D converters 241 to 244. n The storage unit 33 performs calculation processing on the received data of the reflected waves supplied from the A / D converters 241 to 244, thereby detecting dirt on the target 4 and the cover 3. n The data received from the sensor, threshold data used in detecting dirt, and detection results of dirt detection are stored, and the stored data can be called up as needed for later processing.

[0019] The control unit 31 and processing unit 32 are configured as computers, i.e., they include processors such as a CPU and a DSP, and memories such as a ROM and a RAM. The storage unit 33 includes non-volatile memory such as a hard disk or a flash memory. The processing modes of the control processing unit 30 described above are described by programs stored in the storage unit 33, and the functions are realized by the computers of the control unit 31 and processing unit 32 executing the programs. The control unit 31 and processing unit 32 may each be configured as separate hardware, or both functions may be realized by a single piece of hardware.

[0020] Next, the operation of the radar device 1, i.e., a detection method according to an embodiment of the present invention, will be described with reference to Figures 2 to 6. Figure 2 is a flowchart of the entire detection method, Figure 3 is a flowchart of the first processing mode (step 104), Figure 4 is a flowchart of the second processing mode (step 105), and Figure 6 is a flowchart of the target detection process (step 400) executed during operation in the second processing mode.

[0021] The overall flowchart of FIG. 2 starts at a predetermined timing, for example, when the ignition key of the mobile object is turned on and power supply to the radar device 1 is started. First, the control unit 31 controls the modulation unit 12 to transmit a signal wave from the transmitting antenna 11 (step 101). The signal wave is composed of a signal pattern in which a plurality of pulse signals, the center frequencies of which are varied to a plurality of frequencies with a predetermined frequency difference, are repeated in sequence. For example, after a pulse signal with a center frequency f1, a pulse signal with a center frequency f2 that is 10 MHz different from f1 is transmitted, and then a pulse signal with a center frequency f3 that is 10 MHz different from f2 (i.e., 20 MHz different from f1) is transmitted. After a predetermined time has elapsed, the pulse signals of f1, f2, and f3 are transmitted in sequence again, and thereafter, the pulse signals of f1, f2, and f3 are transmitted in sequence every predetermined time. This signal wave pattern is transmitted.

[0022] Next, the control unit 31 controls the receiving unit 20 to receive the signal wave reflected by the target 4 and the cover 3 through the receiving antennas 211...21. n (Step 102), and the signal is received by the amplifiers 221, 222, and processed (Step 103). n Amplification processing by the demodulator 231 . . . 23 n demodulation processing by the A / D converter 241...24 n and transmits the converted digital signal to the control processing unit 30.

[0023] The received reflected waves include waves reflected from the cover 3 (waves reflected from a predetermined distance) and waves reflected from the target 4 (waves reflected from the radar's detection range excluding the range up to the predetermined distance). The processing unit 32 executes a first processing mode in which it processes the reflected waves from the predetermined distance, detects dirt on the cover 3, and transmits the detection result to the host device 2 (step 104). Next, the processing unit 32 executes a second processing mode in which it removes reflected wave components from the predetermined distance (short-distance components) from the digital signal of the received reflected waves, detects the target 4, and transmits the detection result to the host device 2 (step 105).

[0024] Next, the operation of the first processing mode (step 104) will be described in detail based on the flowchart of Fig. 3. First, the processing unit 32 calculates the amplitude of the reflected wave from a predetermined distance from the received reflected wave (step 201). The reflected wave includes a reflected wave reflected by the cover 3 (a reflected wave from a predetermined distance) and a reflected wave reflected by the target 4 (a reflected wave from the radar detection range excluding the range up to the predetermined distance). n Since the distance (predetermined distance) to the cover 3 is known, the time from transmission of the signal wave to reception of the reflected wave can be determined, and the reflected wave reflected by the cover 3 can be identified from the digital signal of the reflected wave and its amplitude can be calculated.

[0025] Next, the processing unit 32 compares the amplitude of the reflected wave reflected by the cover 3 with the amplitude of the reflected wave when the cover 3 is clean (step 202). For example, when the radar device 1 is shipped, the magnitude of the reflected wave when the cover 3 is clean is stored in the memory unit 33. The stored amplitude is read out and compared with the amplitude of the reflected wave received during normal operation of the radar device 1. If the result of the comparison shows that the difference between the amplitude of the reflected wave received during normal operation and the amplitude of the reflected wave when the cover 3 is clean exceeds a predetermined threshold, the processing unit 32 determines that there is dirt that will cause a degradation of radar performance (step 203) and notifies the host device 2 by transmitting a signal indicating the presence of dirt (step 204). Upon receiving the signal indicating the presence of dirt, the host device 2 notifies the user using a display device of the car navigation system, an alarm sound, or the like. On the other hand, if the difference between the amplitude of the reflected wave when the cover 3 is clean and the amplitude of the reflected wave when the cover 3 is clean is equal to or less than the predetermined threshold, the processing unit 32 determines that there is no dirt that will cause a degradation of radar performance (step 203) and ends the processing.

[0026] Next, the principle and operation of the second processing mode (step 105) will be described in detail. Fig. 4 is an explanatory diagram of the principle of the second processing mode, and Fig. 5 is a flowchart showing the operation of the second processing mode (step 105).

[0027] First, the principle of the second processing mode will be explained. Figures 4(a) to 4(c) are diagrams showing vectors of beat signals corresponding to three frequencies contained in the reflected wave. The beat signal is a composite vector of a target component made up of a reflected wave reflected from the target 4 and a short-distance component (a component reflected from a predetermined distance) made up of a reflected wave reflected from the cover 3.

[0028] Since the round-trip distance between transmission and reception is short, the short-distance component has a constant phase and intensity almost regardless of the frequency shift, so by performing differential processing between the beat signal corresponding to center frequency f1 and the beat signal corresponding to center frequency f2, we can obtain the difference vector (1) of the beat signal from which the short-distance component has been removed, as shown in (d) and (e) of Figure 4. Similarly, by performing differential processing between the beat signal corresponding to center frequency f2 and the beat signal corresponding to center frequency f3, we can obtain the difference vector (2) of the beat signal from which the short-distance component has been removed, as shown in (d) and (e) of Figure 4.

[0029] The phase φ of the target component is determined by the round-trip distance 2r between the radar device and the target for the wavelength λ of the radar wave, as shown in the following equation:

[0030]

number

[0031] where: fn=f1+Δf·(n-1): Center frequency of radar wave. n=1,2,3 c: speed of light is.

[0032] Furthermore, the amount of phase change Δφ when the frequency is shifted by Δf is expressed by the following equation.

[0033]

number

[0034] Although this Δφ cannot be found directly from the vector of the beat signal, it can be found by using the vector difference between the combination of f2 and f1 or the combination of f3 and f2.

[0035] Next, the operation of the second processing mode (step 105) will be described in detail with reference to the flowchart in Fig. 5. First, the processing unit 32 generates beat signals corresponding to two frequencies with a predetermined frequency difference Δf by differential processing of measured beat signals of reflected waves corresponding to three frequencies from the storage unit 33 (step 301). Next, the processing unit 32 generates separated beat signals in which the azimuth angles or distances of multiple targets are separated from each other while maintaining phase information for each of the beat signals corresponding to the two frequencies (step 302).

[0036] Furthermore, the processing unit 32 estimates the distance r from the target as the position of the target from the predetermined frequency difference Δf and the phase difference Δφ between the separated beat signals corresponding to the two frequencies (step 303). Specifically, the processing unit 32 estimates the distance r from the target from the phase difference Δφ between the separated beat signals corresponding to the two frequencies using the above equation (1) based on the predetermined frequency difference Δf and the speed of light c. In this way, the processing unit 32 of the control processing unit 30 estimates the position of the target 4 from the phase difference Δφ of the beat signals corresponding to the multiple frequencies f1, f2, and f3 contained in the reflected waves reflected by the target 4 and the cover 3, the reflected waves being generated by changing the center frequency to multiple frequencies f1, f2, and f3 by the predetermined frequency difference Δf (e.g., 10 MHz). Furthermore, target detection processing is performed (step 400).

[0037] The operation of the target detection process (step 400) will be described in detail with reference to the flowchart in FIG. 6. First, the processing unit 32 performs a velocity calculation process to convert the A / D sampled digital signal data of the reflected wave on the time axis into a waveform on the frequency axis (step 401). The frequency data represents the relative velocity (Doppler) of the reflecting object contained in the reflected wave. Converting the data to the frequency axis makes it possible to identify multiple objects at the same distance from the Doppler information. Next, the processing unit 32 performs a response conversion process to extract points where the signal is reflected by the target 4 by threshold processing of the received signal (step 402). The response data contains information on the distance, relative velocity, and angle from the radar device 1. Next, the processing unit 32 performs a clustering process to estimate points originating from the same target as a cluster and estimate the movement state from the transition of the cluster's behavior (step 403). Finally, the clustered data is itemized by threshold processing to detect the target 4 that the radar device 1 actually wants to detect (step 404).

[0038] Through the above processing, the radar device 1 can detect dirt on the cover 3. The detection information of the radar device 1 is transmitted to the higher-level device 2. In this way, by processing the reflected waves from a predetermined distance to detect dirt on the cover 3, and then removing the reflected wave components from the predetermined distance to detect the target, it is possible to provide a radar device and a detection method that can improve the accuracy of dirt detection and thereby improve the accuracy of distance calculation to the target 4.

[0039] In the above-described embodiment, in step 203 of the first processing mode, only the presence or absence of contamination is detected using a single threshold. However, multiple thresholds may be set to detect the degree of contamination in addition to the presence or absence of contamination. For example, threshold values ​​corresponding to five levels of contamination are set, in order from least to most severe: “radar performance degradation (small),” “radar performance degradation (medium),” “radar performance degradation (large),” “cleaning required,” and “maintenance (repair) required.” The degree of contamination is detected by comparing the amplitude of a reflected wave received from a predetermined distance during normal operation of the radar device 1 with the amplitude of the reflected wave when the cover 3 is clean (e.g., the amplitude of the reflected wave in the initial state at the time of shipment of the laser device 1). The magnitude of the difference between the two is then compared with the threshold corresponding to each level of contamination. In step 204, the processing unit 32 notifies the host device 2 of the detection result of the degree of contamination by transmitting a signal indicating the degree of contamination. In this way, by detecting the degree of contamination in addition to the presence or absence of contamination, the host device 2 and the user can take appropriate measures according to the degree of contamination.

[0040] If the detected level of dirt is "cleaning required," the processing unit 32 transmits a signal to the host device 2 indicating that cleaning of the cover 3 is required. Upon receiving the signal, the host device 2 notifies the user by using the display device of the car navigation system, an alarm sound, or the like, to urge the user to clean the cover 3. Subsequently, the host device 2 receives a user input indicating that cleaning is complete via a user interface such as the car navigation system, and transmits a signal indicating that cleaning is complete to the control processing unit 30. If the processing unit 32 of the control processing unit 30 detects a level of dirt that is determined to be "cleaning required" despite receiving the signal, it determines that the detected dirt is not cleanable and transmits a signal indicating that repair of the cover 3 is required to the host device 2, instead of a signal indicating that cleaning of the cover 3 is required. This processing enables robust dirt detection.

[0041] Next, a modified example of the operation of the radar device 1, that is, a modified example of the detection method of the present invention, will be described. Fig. 7 shows an overall flowchart of the modified example. In this modified example, when contamination of the cover 3 is detected, the cause of the contamination is determined from the magnitude of the time variation in the amplitude of the reflected wave reflected by the cover 3. To make such a determination, in this modified example, the processing contents of the first processing mode (step 104') and the second processing mode (step 105') are different from those of the detection method shown in Fig. 2. The other processing (steps 101 to 103) are the same as those of the detection method shown in Fig. 2.

[0042] First, the control unit 31 controls the modulation unit 12 to transmit a signal wave from the transmitting antenna 11 (step 101). The signal wave is composed of a signal pattern in which a plurality of pulse signals, each having a center frequency varied to a plurality of frequencies with a predetermined frequency difference, are repeated in sequence. Next, the control unit 31 controls the receiving unit 20 to receive the signal wave reflected by the cover (a reflected wave from a predetermined distance) and the signal wave reflected by the target (a reflected wave from the radar detection range excluding the range up to the predetermined distance), and transmit the reflected wave to the receiving antennas 211...21. n (step 102 ), performs reception processing (step 103 ), and transmits the converted digital signal to the control processing unit 30 .

[0043] Next, the processing unit 32 executes a first processing mode in which it detects dirt on the cover 3 from the amplitude of the reflected wave from a predetermined distance (the distance between the radar device 1 and the cover 3) (step 104'). In this modified example, if the processing unit 32 detects dirt, it records the state of the dirt in the storage unit 33. Next, the processing unit 32 executes a second processing mode in which it detects the target 4 by removing the reflected wave component from the predetermined distance (the distance between the radar device 1 and the cover 3) from the digital signal of the received reflected wave, and transmits the detection result to the higher-level device 2. In the second processing mode of this modified example, it also reads out the state of dirt recorded in the storage unit 33, and if dirt is present, it also performs processing to determine the cause of the dirt from the magnitude of the time variation in the amplitude of the reflected wave reflected by the cover 3 (step 105').

[0044] Next, the operation of the first processing mode (step 104') of the modified example will be described in detail based on the flowchart of Fig. 8. First, the processing unit 32 calculates the amplitude of the reflected wave from a predetermined distance from the received reflected wave (step 201). The reflected wave includes the reflected wave reflected by the cover 3 (the reflected wave from the predetermined distance) and the reflected wave reflected by the target 4 (the reflected wave from the radar detection range excluding the range up to the predetermined distance). n Since the distance (predetermined distance) to the cover 3 is known, the time from transmission of the signal wave to reception of the reflected wave can be determined, and the reflected wave reflected by the cover 3 can be identified from the digital signal of the reflected wave and its amplitude can be calculated.

[0045] Next, the processing unit 32 compares the amplitude of the reflected wave reflected by the cover 3 with the amplitude of the reflected wave when the cover 3 is clean (step 202). For example, when the radar device 1 is shipped, the amplitude of the reflected wave when the cover 3 is clean is stored, and the stored amplitude is compared with the amplitude of the reflected wave received during normal operation of the radar device 1. If the result of the comparison shows that the difference between the amplitude of the reflected wave received during normal operation and the amplitude of the reflected wave when the cover 3 is clean exceeds a predetermined threshold, the processing unit 32 determines that there is dirt that will cause a degradation of radar performance (step 203) and records information indicating that there is dirt in the storage unit 33 (step 205). On the other hand, if the difference between the amplitude of the reflected wave when the cover 3 is clean and the amplitude of the reflected wave when the cover 3 is clean is equal to or less than the predetermined threshold, the processing unit 32 determines that there is no dirt that will cause a degradation of radar performance (step 203) and ends the processing.

[0046] Next, with reference to FIG. 9, the operation of a modified example of the second processing mode (step 105') will be described in detail. The second processing mode (step 105') differs from the second processing mode (step 105) shown in FIG. 5 in that a process for determining the cause of contamination (steps 304 to 307) is performed between the separated beat signal generation process (step 302) and the target position estimation process (step 303). The operations of steps 301, 302, 303, and 400 are the same as those of the second processing mode of FIG. 5. Therefore, the following description will focus on the differences from the second processing mode of FIG. 5, namely, the process for determining the cause of contamination (steps 304 to 307).

[0047] After the separated beat signal generation process (step 302), the processing unit 32 calls up information indicating the state of dirt stored in the storage unit 33. If dirt is detected in the dirt detection process (step 104') (step 304), a difference vector intensity calculation process is performed to calculate the temporal difference in the amplitude of the reflected wave reflected from the cover 3 (step 305). That is, the amplitude of the reflected wave reflected from the cover 3, which is sampled at a predetermined period, is read from the storage unit 33 at each predetermined sampling period, and the difference is calculated to determine the magnitude of the temporal fluctuation in the amplitude of the reflected wave.

[0048] Next, the processing unit 32 determines the cause of the stain by comparing the magnitude of the obtained time fluctuation with a threshold value (step 306). For example, if the detected stain is mud, the mud fluctuates over time, so the difference in amplitude level is relatively large and changes continuously over time. On the other hand, if the detected stain is a scratch or dent, its condition will not change unless a new scratch or dent is formed, so the difference in amplitude level will be intermittent over time, and the difference in the time region that does not change will be close to zero. Therefore, the cause of the stain can be determined by comparing the magnitude of the time fluctuation with a threshold value.

[0049] Thereafter, the processing unit 32 notifies the host device 2 by transmitting a signal indicating the presence of dirt and a signal indicating the cause of the dirt (step 307). Upon receiving the signal, the host device 2 notifies the user using the display device of the car navigation system, an alarm sound, or the like. Furthermore, the host device 2 may notify the user of the need for action depending on the cause of the dirt, such as the need for cleaning or maintenance. Thereafter, the processing unit 32 performs a position estimation process for the target 4 (step 303). Furthermore, the processing unit 32 performs a target detection process (step 400).

[0050] On the other hand, if the information indicating the state of contamination is not stored in the memory unit 33, the processing unit 32 determines that there is no contamination that would cause a decrease in radar performance (step 304), and performs a process of estimating the position of the target 4 (step 303).Furthermore, a target detection process is performed (step 400).

[0051] Through the above processing, the radar device 1 can detect dirt on the cover 3. This makes it possible to provide a radar device and a detection method that can improve the accuracy of dirt detection and thereby improve the accuracy of distance calculation to the target 4. Furthermore, it becomes possible to determine the cause of dirt that may reduce the detection performance of the radar device 1, allowing the user to take appropriate action.

[0052] The radar device and detection method according to the present invention have been described above, but the present invention is not limited to the above-described embodiments and includes all aspects encompassed by the concept of the present invention and the scope of the claims. For example, the radar device 1 described in the embodiment employs a pulse system, but may employ an FCM (Fast Chirp Modulation) system. Furthermore, in the above-described modified examples (FIGS. 7 to 9), the process of determining the cause of contamination (steps 304 to 307) is performed as part of the second processing mode (step 105'). However, as long as it is performed after the first processing mode, it may be performed separately from the second processing mode, for example, between the first processing mode (step 104') and the second processing mode (step 105'). [Explanation of symbols]

[0053] 1. Radar equipment 2 Upper device 3 Cover (bumper) 4 Target 10 Transmitter 11 Transmitting Antenna 12 Modulation section 13 Local oscillator section 20 Receiving unit 211, 21 n Receiving antenna 221, 22 n Amplification section 231, 23 n Demodulation section 241, 24 n A / D conversion section 30 Control processing section 31 Control Unit 32 Processing section 33 Storage section

Claims

1. A radar device having a cover disposed on the front surface at a predetermined distance, a transmitting unit that transmits a signal wave; a receiving unit that receives the reflected signal wave; a control processing unit having a first processing mode for processing reflected waves from the predetermined distance to detect dirt on the cover, and a second processing mode for processing reflected waves from a radar detection range excluding the range up to the predetermined distance to detect a target; Equipped with The control processing unit In the first processing mode, contamination of the cover is detected from the amplitude of a reflected wave reflected by the cover; In the second processing mode, components up to the predetermined distance are removed from the reflected wave to detect a target within a detection range of the radar; the control processing unit detects the presence or absence of contamination by comparing the amplitude of the reflected wave reflected by the cover with the amplitude of the reflected wave when the cover is not dirty; when the presence of the dirt is detected, the control processing unit determines a cause of the dirt from a magnitude of a time variation in the amplitude of the reflected wave reflected by the cover. Radar equipment.

2. A radar device having a cover disposed on the front surface at a predetermined distance, a transmitting unit that transmits a signal wave; a receiving unit that receives the reflected signal wave; a control processing unit having a first processing mode for processing reflected waves from the predetermined distance to detect dirt on the cover, and a second processing mode for processing reflected waves from a radar detection range excluding the range up to the predetermined distance to detect a target; Equipped with The control processing unit In the first processing mode, contamination of the cover is detected from the amplitude of a reflected wave reflected by the cover; In the second processing mode, components up to the predetermined distance are removed from the reflected wave to detect a target within a detection range of the radar; the control processing unit compares the amplitude of the reflected wave reflected by the cover with the amplitude of the reflected wave when the cover is not dirty, thereby detecting the presence or absence of the dirt and the degree of the dirt; The control processing unit When the degree of contamination is detected to exceed a predetermined level, a signal is generated indicating that the cover needs to be cleaned; a signal indicating that the cover needs repair when the level of contamination exceeds the predetermined level despite receiving a signal indicating that the cleaning has been completed; Radar equipment.

3. the transmitting unit transmits the signal wave whose center frequency is changed to a plurality of frequencies with a predetermined frequency difference; the control processing unit estimates the position of the target based on a phase difference between beat signals corresponding to the plurality of frequencies included in the reflected wave and the predetermined frequency difference.

3. The radar device according to claim 1 or 2.

4. transmitting a signal wave by a radar device having a cover disposed in front of the radar device at a predetermined distance; a step of reflecting the signal wave and receiving the reflected wave by the radar device; detecting contamination on the cover by processing reflected waves from the predetermined distance using the radar device; removing, by the radar device, components up to the predetermined distance from the reflected wave, and detecting a target within a detection range of the radar device; Including, The step of detecting the contamination includes: comparing the amplitude of the reflected wave reflected by the cover with the amplitude of the reflected wave when the cover is not dirty, thereby detecting the presence or absence of the dirt; a step of determining a cause of the contamination based on a magnitude of a time variation in the amplitude of a reflected wave reflected by the cover when the contamination is detected; Including, Detection method.

5. A step of transmitting a signal wave by a radar device having a cover disposed in front of the radar device at a predetermined distance; a step of reflecting the signal wave and receiving the reflected wave by the radar device; detecting contamination on the cover by processing reflected waves from the predetermined distance using the radar device; a step of removing components up to the predetermined distance from the reflected wave by the radar device and detecting a target within a detection range of the radar; Including, The step of detecting the contamination includes: a step of detecting the presence or absence of contamination and the degree of contamination by comparing the amplitude of the reflected wave reflected by the cover with the amplitude of the reflected wave when the cover is not soiled; generating a signal indicating that the cover needs cleaning when the degree of soiling is detected to exceed a predetermined degree; transmitting a signal indicating that the cover needs repair when detecting that the degree of soiling exceeds the predetermined degree despite receiving a signal indicating that the cleaning has been completed; Including, Detection method.

6. The transmitting step includes a step of transmitting the signal wave whose center frequency is changed to a plurality of frequencies with a predetermined frequency difference, the step of detecting the target includes a step of estimating a position of the target from a phase difference of beat signals corresponding to the plurality of frequencies included in the reflected wave and the predetermined frequency difference. The detection method according to claim 4 or 5.

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