JP2004198438A - Onboard radar equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high precision information about a target, based on the exploration result with respect to the target by an FM-CW system. <P>SOLUTION: A target 22 exploration is conducted by transmitting an exploration signal 40 for each constant angle, while scanning with an antenna 23. The exploration signal is deviated in angle at transmission between round trip exploration. The direction of the target 22 is detected with a precision which is similar to that when exploring with fine angular difference, by combining the exploration results with the angles deviated in several scannings. The relative shift of the target 22, resulting from a plurality of times of scannings, is considered as the Doppler shift, and the data are combined taking into consideration the deviation in the frequency. The data which cannot be combined are processed as unwanted reflected objects, and the position where the unwanted reflected objects gather is obtained, which is decided as being a load shoulder. The height of a stationary target is decide from the fluctuation state of the reflected signal level, when approaching the stationary target. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an on-vehicle radar device that is mounted on a vehicle and is used to search for an obstacle around a vehicle, for example, an obstacle such as another vehicle traveling ahead as a target, and to ensure safety of traveling.

  2. Description of the Related Art Conventionally, an in-vehicle radar device for searching for an obstacle such as a traveling direction of a vehicle has been developed. The in-vehicle radar device extracts the beat signal of the frequency beat generated by the exploration wave, which is a continuous transmission wave frequency-modulated using a triangular wave as a modulation signal, and the reflected wave from the target, and based on the beat signal frequency, An FM-CW method is used to obtain a relative speed and a relative distance from the FM-CW. Prior art relating to the FM-CW radar is disclosed in, for example, Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4. In particular, Patent Literature 2 discloses that the irradiation direction of a beam-shaped radio wave transmitted from an on-vehicle radar device can be changed so that a target such as a vehicle traveling diagonally forward, for example, when traveling on a curve, is accurately searched for. Is disclosed.

  FIG. 16 shows a schematic configuration of a conventional on-vehicle radar device 1 of the FM-CW system. The on-vehicle radar device 1 searches for the target 2 and transmits a search radio wave from the antenna 3 to calculate the distance to the target 2 and the relative speed between the target 2. The antenna 3 receives a radio wave reflected by the target 2. Since the antenna 3 is formed so that the range where the gain is high has a sharp beam shape, the scanning mechanism 4 performs scanning to change the beam direction, and performs scanning by changing the beam direction when the reflected signal from the target 2 is received. The second direction can also be detected. When the distance and the direction to the target 2 are known, the position of the target 2 can be relatively determined based on the own vehicle.

  In the search of the FM-CW method, a search signal frequency-modulated with a triangular wave is given from the transmission circuit 5 to the antenna 3 to be transmitted, and a reflection signal received by the antenna 3 is amplified or frequency-converted by the reception circuit 6, and the analog signal is output. The signal is converted into a digital signal by a digital / digital conversion (hereinafter abbreviated as “A / D”) circuit 7, and is converted into a frequency component by a fast Fourier transform (hereinafter abbreviated as “FFT”) circuit 8. The target detection circuit 9 calculates a distance R to the target 2 and a relative speed V based on the frequency components from the FFT circuit 8.

  FIG. 17 illustrates a principle in which the target detection circuit 9 illustrated in FIG. 16 searches for the target 2 and calculates the distance R and the relative speed V by the FM-CW method. A search signal 10 of a continuous wave (CW) FM-modulated so that the frequency continuously changes on a triangular wave at a constant change speed is transmitted from the antenna 3 of FIG. Since the search signal 10 is reflected by the target 2 and the reflected signal 11 received by the antenna 3 is delayed by a time corresponding to the distance R as compared with the search signal 10 as shown in FIG. There is a difference in frequency with respect to the search signal 10 whose frequency is changing. Further, since the relative velocity V occurs between the target 2 and the target 2, the Doppler shift effect also occurs in the reflection signal 11, which causes a difference in frequency between the reflection signal 11 and the search signal 10.

  In the FM-CW method, an upbeat signal 12 which is a beat signal in a frequency rising section where the frequency shift amount of frequency modulation increases, and a downbeat signal 13 which is a beat signal in a falling section where the frequency shift amount decreases. As shown in FIG. 17B, the frequency change due to the Doppler shift effect is reflected differently. Therefore, the frequency fub of the upbeat signal 12 and the frequency fdb of the downbeat signal 13 are obtained by using the range frequency fr and the Doppler shift frequency fd, which are the standard beat signal frequencies, in the following equations 1 and 2. It can be expressed as follows.

fub = fr−fd (1)
fdb = fr + fd (2)

  Here, the range frequency fr is proportional to the distance R to the target 2, and if the amplitude of the frequency shift as a triangular wave of the search signal 10 of the FM-CW method is Δf, the modulation frequency fm as a triangular wave, and the speed of light are C, Equation 3 The Doppler shift frequency fd is represented by the following equation 4, where V is the relative velocity with respect to the target 2 and λ is the wavelength of the search signal 10. The distance R and the relative velocity V can also be calculated from the range frequency fr and the Doppler shift frequency fd using the relations of Expressions 3 and 4.

  As shown in FIG. 16, prior art relating to an on-vehicle radar device that scans the beam direction of the antenna 3 is disclosed in, for example, Patent Document 5, Patent Document 6, Patent Document 7, Patent Document 8, and the like. Patent Document 9 discloses a configuration in which a range for searching a target is switched between a short range and a long range. Patent Document 10 discloses a prior art in which a target such as a flying object is specified using a part of data obtained during radar search. Patent Literature 11 discloses a prior art in which an obstacle is three-dimensionally recognized using a vehicle-mounted radar.

JP-A-52-111395 JP-A-7-120549 JP-A-9-80148 JP-A-9-145824 JP-A-11-64499 JP-A-11-72651 JP-A-11-84001 JP-A-11-231053 JP-A-8-82679 JP-A-10-282220 JP-A-11-38141

  Among the prior arts for scanning the beam direction of an antenna, for example, Patent Documents 7 and 8 disclose a method in which a plurality of searches are performed during one scanning period and a reflected signal level obtained in response to a change in the beam direction. The concept of estimating the direction of the target from the peak of the target is shown. In order to increase the search accuracy in the direction of the target based on the concept of the prior art, it is necessary to increase the number of searches by increasing the search direction in one scan. However, in such a method, arithmetic processing and the like are added, and high-speed processing requires hardware for high-speed signal processing. Increasing the speed of signal processing causes problems such as heat generation as well as cost, and requires a certain circuit scale for smooth use, resulting in an increased system configuration.

  Although there is a method of narrowing an angle range in which a search is performed in a specific section where a target exists, the hardware configuration is complicated and there are not many merit in cost.

  In target recognition, when a reflected signal from a guardrail, a tunnel, a sound barrier, or the like is also received, it is necessary to form complicated logic to extract a true target. For example, in the case of a guardrail, the relative speed calculated after performing the pairing process of combining the frequencies of the frequency rising section and the frequency falling section in the FM-CW method never becomes the same value as the own vehicle speed. Looks like a moving object, not a stationary object. In addition, since the distance movement amount does not match the value obtained from the relative speed, it can be determined that the vehicle is a guardrail based on these values. However, when the frequency of the exploration increases, the data update rate increases, and the amount of distance movement decreases. Therefore, even if the relative speed is obtained from the distance movement amount, the accuracy becomes coarse, and it becomes difficult to compare the relative speeds.

  Further, in the case of the FM-CW method, the distance and the relative speed are calculated by combining the frequency rising section and the falling section. However, for an object approaching at a high relative speed, the Doppler shift effect largely occurs. The frequency difference between the section and the descending section becomes large. Also, in the case of a target approaching, the beat signal in the frequency rising section shifts to the lower frequency side, and it becomes difficult to process the beat signal that is too low. turn into. As a result, tracking of the approaching target cannot be performed, and information about whether the approaching target is approaching or the direction deviating cannot be obtained.

  Further, when it is determined that the target detected during traveling is a stationary object, an object that the vehicle can step over or pass through is also included. Conventionally, there is no particular criterion for these objects, and even objects that can be stepped over are subject to alarm and deceleration control. Regarding these, it is conceivable to take a method of excluding from a control object without determining a stationary object as a target, but in the case of an object that cannot be stepped over or passed through, a method of excluding from a control object Can not take.

  An object of the present invention is to provide an on-vehicle radar device capable of accurately recognizing the position and properties of a target.

The present invention is mounted on a vehicle, an in-vehicle radar device for searching for a target around the vehicle,
An antenna formed to have a high gain in a predetermined beam direction, transmitting a search signal in the beam direction, and receiving a reflected signal from a target for the search signal;
The distance to the target is calculated based on the reflected signal from the target received by the antenna and the search signal transmitted from the antenna, and the target is recognized based on the distance and the beam direction of the antenna detected by the direction detecting means. And a target recognition means for judging the height of a stationary target by determining whether or not the influence of multipath is reflected in the change in the reflected signal level due to the distance in the specific frequency range. This is a vehicle-mounted radar device.

  According to the present invention, when approaching a stationary target, it is determined whether or not the target can cross over based on a change in the level of the reflected signal from the target with distance. The signal reflected from the target includes a signal received directly by the antenna and a signal reflected and received on the road surface, and a phase difference based on a path difference of the reflected signal occurs, and a signal level received by the antenna fluctuates. I do. When the height of the target is low, the level fluctuation of the reflected signal is small, and there is a high possibility that the target can be crossed. Since it is determined whether or not it is possible to step over based on a change in the level of the reflected signal due to the distance from the target, a reliable determination can be made with a simple configuration. In addition, the reflected signal from the target on the road surface on which the vehicle is traveling passes through a plurality of paths, a path directly received by the antenna and a path once reflected by the road surface and then received by the antenna, resulting in a path difference. Received in a state where a phase difference based on the generated phase difference occurs. Since a phase difference occurs between the reflected signals received in the reception in such a multipath state, if the phase difference is close to 180 degrees, the amount of signal attenuation increases. Since the influence of such a multipath appears according to the height of the target, it is possible to appropriately determine the height of the stationary target based on the influence of the multipath.

  In the present invention, the target recognizing means determines that the target can be crossed when the level of the reflected signal from the stationary target sharply decreases during the approach. I do.

  According to the present invention, when the level of the reflected signal from the stationary target rapidly decreases during the approach, it is determined that the target can be crossed. The target that can be stepped over has a low height from the road surface and, when the distance to the antenna is small, does not fall within the range of the beam direction of the antenna, so that the level of the reflected signal sharply decreases. Therefore, when the level of the reflected signal rapidly decreases during the approach, the possibility that the target is at least lower than the position of the antenna is high, and the possibility that the target can be crossed is high.

  Further, in the present invention, the target recognizing means has, in advance, data indicating a change in a threshold value of a reflection signal level with respect to a distance with respect to a stationary target to be recognized. When it is smaller than the target, it is determined that the target can be stepped over.

  According to the present invention, for a stationary target to be recognized, a map indicating a change in the threshold value of the reflection signal level with respect to the distance is formed in advance, so that if the reflection signal level when approaching the stationary target drops below the threshold value, It can be determined that the height of the stationary target is low and there is a high possibility that the target can be stepped over.

Further, the present invention is mounted on a vehicle, in a vehicle-mounted radar device for searching for a target around the vehicle,
An antenna that is formed so as to have a high gain in a predetermined beam direction, transmits a search signal in the beam direction, and receives a reflected signal from the target with respect to the search signal; and a reflected signal from the target and an antenna received by the antenna. The distance to the target is calculated based on the search signal transmitted from the target, and the target is recognized based on the distance and the beam direction of the antenna detected by the direction detecting means. And target recognition means for determining the height of the target based on a distance at which the level of the reflected signal from the stationary target is smaller than the threshold. This is a vehicle-mounted radar device.

  According to the present invention, the distance at which the fall of the reflected signal level when approaching the stationary target is smaller than the threshold value drawn on the map corresponds to the height of the stationary target, so if the distance falls from a relatively long distance, It is determined that the height is low, and that the higher the height is, the lower the height is, and the higher the height is.

  Further, in the present invention, the target recognizing means determines whether or not the stationary target can be stepped over based on a state in which the reflection signal level decreases as the distance approaches.

  According to the present invention, when the fall of the reflected signal level when approaching a stationary target is more than a certain level than the level at a long distance, it is determined that the stepping can be performed, and the reflected signal level due to a difference in the material of the target and the like is determined. The effects of changes can be avoided.

Further, the present invention is mounted on a vehicle, in a vehicle-mounted radar device for searching for a target around the vehicle,
An antenna that is formed so as to have a high gain in a predetermined beam direction, transmits a search signal in the beam direction, and receives a reflected signal from the target with respect to the search signal; and a reflected signal from the target and an antenna received by the antenna. Calculates the distance to the target based on the search signal transmitted from the target, and recognizes the target based on the distance and the beam direction of the antenna detected by the direction detecting means, and the reflected signal level sharply increases with approach. And a target recognizing means for judging the height of the stationary target based on a distance that decreases.

  According to the present invention, the height of a stationary target is estimated in accordance with the distance at which the amount of decrease in the reflected signal level when approaching a stationary target becomes greater than or equal to a certain level from the reflected signal level at a long distance. When the height of the stationary target is relatively low, the target is out of the range of the beam from the antenna even at a relatively long distance, and a drop in the received signal level is avoided. If the height of the target is relatively high, the fall of the reflected signal level becomes large after the distance becomes short. Since the target of the drop amount is the reflected signal level of the target itself at a long distance, the influence of the difference in the material of the target or the like can be reduced, and the height of the target can be accurately estimated.

Further, the present invention is mounted on a vehicle, in a vehicle-mounted radar device for searching for a target around the vehicle,
An antenna that is formed to have a high gain in a predetermined beam direction, transmits a search signal in the beam direction, and receives a reflected signal from the target with respect to the search signal; and a reflected signal from the target and an antenna received by the antenna. A target recognition unit that calculates a distance to the target based on the search signal transmitted from the target and recognizes the target based on the calculation result,
The target recognizing means, when recognizing a target that is stationary at a distance more than a predetermined distance, when the level of the reflected signal at the time of recognition is larger than a predetermined reference and is closer than the vehicle position at the time of recognition. The vehicle-mounted radar device is characterized in that when the level of the reflected signal of the target falls greatly, the target is recognized as not being a target whose height should be monitored against the running of the vehicle.

  According to the present invention, when recognizing a target that is stationary at a distance more than a predetermined distance, when the level of the reflected signal at the time of recognition is larger than a predetermined reference and closer to the position at the time of recognition. When the fall of the level of the reflected signal is large, it is recognized that the target is not a target whose height should be watched for the running of the vehicle. For example, when receiving a reflected signal from an object above the road surface on which a vehicle passes, such as at a signboard, sign, or a grade separation, if the antenna is in a range close to the beam direction of the antenna at a distance, Out of the range of the beam direction, and the drop of the level of the reflected signal becomes large. When such an object that does not hinder traveling is detected, it is recognized that the target is not a target to be warned about, so that it is possible to prevent unnecessary control such as an alarm or braking.

  In the present invention, the height of the target is a height of a highest portion of the target.

  According to the present invention, the possibility of stepping over can be determined based on the height of the highest portion of the target.

  Further, in the present invention, the target recognizing means determines whether or not the target can cross over based on the determined height.

  According to the present invention, it is determined whether or not it is possible to step over the highest part of the target, so that a reliable determination can be made.

  In the present invention, the height of the target is a height of a lowest part of the target.

  According to the present invention, it is possible to judge the possibility of passing through based on the height at the lowest part of the target.

  In the present invention, the target recognizing means determines whether or not the target can pass through based on the determined height.

  According to the present invention, it is determined whether or not the target can pass through the lowest part, so that a reliable determination can be made.

  Further, in the present invention, the target recognizing means performs the determination of the height of the target in a plurality of sections according to the distance from the target, and sets a predetermined alarm and / or It is characterized in that a signal for braking is derived.

  According to the present invention, while approaching a stationary target, the height of the target is determined based on the presence or absence of the influence of multipath in a plurality of sections, so that multiple determinations are performed while approaching the target. If it is determined that the target can be stepped over in an early period, unnecessary warnings and braking can be avoided.

In the present invention, the search for the target is performed by an FM-CW method,
When the target recognizing unit determines that the relative speed to the target is higher than the reference speed, the target recognizing unit estimates the distance to the target and the relative speed using only the data in the frequency falling section.

  According to the present invention, accurate detection can be performed even for a target approaching quickly.

  According to the present invention, the height of the target is determined based on the influence of the multipath that becomes conspicuous when the height of the target is high, so that a target that is not affected by the multipath can be stepped over. It is possible to avoid unnecessary deceleration and generation of an alarm by judging that the performance is high.

  According to the present invention, the position of the antenna that transmits the search signal and receives the reflected signal has a certain height from the road surface, and a target lower than this height has a certain distance to the target, By utilizing the phenomenon of deviating from the beam direction of the antenna, it can be reliably determined with a simple configuration whether or not a stationary target can be stepped over.

  Further, according to the present invention, it is possible to easily determine whether or not a stationary target can be stepped over, based on a threshold in a map created in advance.

  Furthermore, according to the present invention, a threshold map of the reception level is provided in advance for a distance serving as a criterion for a drop in the reception level of the reflected signal from the target based on the target being lower than the beam direction of the antenna. Since the height of the target is determined based on the distance at which the level of the reflected signal from the target becomes smaller than the threshold value, the height of the target can be determined quickly.

  Further, according to the present invention, it is determined that the target can be depressed when the amount of drop in the reflected signal level when approaching a stationary target reaches a certain level as compared with the reflected signal level at a distance. Therefore, a highly probable judgment can be made regardless of the material of the target.

  Further, according to the present invention, the height of the target is estimated based on the distance at which the amount of decrease in the reflected signal level that changes according to the distance from the stationary target becomes equal to or less than a certain amount as compared to the distance. For a low target, the probe beam will fall off the target, even at relatively large distances, to avoid a fall in the reflected signal level. For a relatively high target, the beam direction deviates from the target only when approaching a short distance, and the distance at which the fall of the reflected signal level starts is reduced. Since the target height is estimated according to the distance, the target height can be easily and easily estimated, and the target height can be estimated without being affected by the change in the reflected signal level due to the material of the target. Can be accurately estimated.

  Further, according to the present invention, an appropriate judgment is made for a target, such as a signboard, which is detected at a relatively distant place and whose reflected signal level drops sharply when approaching, such as a signboard, which is sufficiently higher than the road surface on which the vehicle is running. Useless alarms and braking can be avoided.

  Further, according to the present invention, it is possible to determine the possibility of stepping over by setting the highest portion of the target as the height.

  Further, according to the present invention, the possibility of stepping over is determined at the highest portion of the target, so that a highly accurate determination can be made.

  Further, according to the present invention, it is possible to determine the possibility of passing through by setting the lowest portion of the target as the height.

  Further, according to the present invention, the possibility of passing through is determined at the lowest part of the target, so that a highly accurate determination can be made.

  Further, according to the present invention, the possibility of stepping over in a plurality of sections approaching the target is determined, so if it is determined that there is a high possibility of stepping over a relatively long distance, control such as deceleration is not performed. In addition, the vehicle can pass beyond the target amount.

  Further, according to the present invention, it is possible to accurately estimate a distance, a position, and the like, even for a target that approaches rapidly.

  FIG. 1 shows a schematic electrical configuration of an on-vehicle radar device 21 used in each embodiment of the present invention. The on-vehicle radar device 21 has an antenna 23 for searching for a target 22. The beam direction 23a of the antenna 23 can be changed in a horizontal plane by the scanning mechanism 24. The scanning mechanism 24 can swing the beam direction 23a of the antenna 23 within a certain angle range with respect to the traveling direction.

  From the antenna 23, an FM-CW radio wave generated by the transmission circuit 25 is transmitted as a search signal. When the search signal strikes the target 22, the signal is reflected on the surface of the target 22 and becomes a reflected signal. When the reflected signal is received by the antenna 23, the beat signal generated between the signal and the search signal is electrically processed by the receiving circuit 26, converted into a digital signal by the A / D circuit 27, and the frequency component is converted by the FFT circuit 28. Is extracted. The target detection circuit 29 detects a target corresponding to the target 22 based on the frequency components extracted by the FFT circuit 28. The target recognition circuit 30 recognizes the target 22 based on detection results of targets in a plurality of search directions in one scan and detection results of targets obtained from a plurality of scans. A plurality of search results in one scan and a search result in a plurality of scans are stored in the memory 31.

  The on-vehicle radar device 21 is mounted on a vehicle 32, and the position of the antenna 23 is higher than a road surface 33 on which the vehicle 32 runs. The result recognized by the target recognition circuit 30 of the on-vehicle radar device 21 is given to an alarm device 34 and a cruise control device 35. The warning device 34 generates a warning when the distance to the target 22 becomes shorter than a predetermined distance and a danger of collision or the like occurs. When it is determined that the distance to the target 22 is short in consideration of the relative speed as well, the cruise control device 35 controls the vehicle 32 so as to apply braking to lower the traveling speed. If braking is unnecessary, control is performed so as to continue running at a preset speed. The beam direction 23a of the antenna 23 can be detected by the direction detecting device 36.

  FIG. 2 shows a processing procedure of the target recognition circuit 30 according to the first embodiment of the present invention. When the target is recognized, the procedure from step a1 is started. In step a2, it is determined whether or not the scanning of the antenna 23 by the scanning mechanism 24 has been completed for one scan. If it is determined that the search has been completed, in step a3, if the number of beams in which the beam direction 23a of the antenna 23 is pointing to one direction and the search signal is being transmitted is three or more, the reflected signal from the target 22 It is determined whether or not is detected. If it is determined that three or more beams have not been detected, it is determined in step a4 whether the target recognized in the previous scan has been detected. If not, the process returns to step a2. If it is determined in step a4 that the target 22 detected in the previous scan is recognized, then in step a5, the angle is calculated from the data of the previous and current two scans. If it is determined in step a3 that three or more beams have been detected, an angle is calculated from one scan data in step a6.

  When the calculation processing in step a5 or step a6 is completed, pairing processing is performed in step a7. In the pairing process, the frequency rise period and the frequency fall period of the FM-CW method are combined. In step a8, it is determined whether or not the pairing process was possible in step a7. When it is determined that the pairing process is not possible, the frequency data is shifted in step a9, the data is divided for each specific section in step a10, the position in each section is calculated in step a11, and the road shoulder position is calculated in step a12. Is determined. For the data that could be paired in step a8, the processing from step a9 to step a12 is not performed. The details of each process from step a9 to step a12 will be described later.

  In step a13, it is determined whether or not there is a target outside the road shoulder. When it is determined that there is a target, in step a14, the target outside the road shoulder is deleted. When it is determined in step a13 that there is no target outside the shoulder of the road, or when step a14 ends, it is determined in step a15 whether there is a stationary target in a stationary state. If it is determined that there is no stationary object target, a signal representing the target recognition result is output in step a16.

  When it is determined in step a15 that there is a stationary target, the probability that the stationary target can be stepped over is calculated in step a17 and subsequent steps. In step a17, the probability value is initialized to zero. In step a18, it is determined whether the power, which is the reception intensity of the stationary target at a long distance, is large. When it is determined that the power is large, the probability value is set to 50 in step a19. If the power at a long distance is large, it is determined that the height of the stationary object target is higher than the road surface. When it is determined in step a18 that the power at a long distance is not large, or when step a19 is completed, it is determined in step a20 whether the power rapidly decreases within a relatively long distance. When it is determined that the target is lowered, the probability that the stationary target is present at a relatively high position such as a signboard increases, and the possibility that the target cannot be crossed decreases. Therefore, the probability value is reduced by 30 in step a21.

  When it is determined in step a20 that the power at a long distance does not suddenly decrease, or when step a21 ends, the process proceeds to step a22. In step a22, it is determined whether the power as the received signal strength varies as the distance approaches, and whether the maximum value of one section A is larger than the minimum value of the next section B. When the received signal level fluctuates due to the multipath phenomenon with respect to the stationary object target, a relationship such as step a22 is established reflecting the period of the fluctuation, and the process proceeds to step a23. In step a23, the probability value is increased by 20. When it is determined in step a22 that the relationship is not established, or when step a23 ends, the process proceeds to step a24. In step a24, it is determined whether the maximum value of the section C is larger than the minimum value of the section D in the next section C determined in step a22 and the next section D. When it is determined that the condition of step a24 is satisfied, the probability value is increased by 20 in step a25. When it is determined in step a24 that the condition is not satisfied, or when step a25 ends, the process proceeds to step a16, where the calculated probability value is output to the alarm device 34, the cruise control device 35, and the like in FIG.

  Similarly, when judging by comparing the “maximum value” and the “minimum value” in the adjacent section, similarly, according to the “maximum variation width” or the “amount of deviation from the average value”, a sharp decrease in power is similarly performed. You can make a decision.

  After the target is output in step a16, or when it is determined in step a2 that one scan has not been completed, the process proceeds to step a26 to end the procedure. If it is determined in step a2 that one scan has not been completed, the target is searched until one scan is completed, and if a reflected signal is detected, the target is recognized. In the next scan, the angle of the beam is shifted by a predetermined angle. The beam angle can be further finely complemented by dividing the scan into three or more scans. The alarm device 34 of FIG. 1 gives an alarm, for example, when the probability given by the target output in step a16 becomes 50% or more. Further, when the probability becomes about 70 to 80%, the cruise control device 35 performs braking for limiting the traveling speed of the vehicle 33.

  FIG. 3 shows a second embodiment of the present invention, in which the operation mechanism 24 shown in FIG. 1 detects the beam direction 23a of the antenna 23 as an angle by the direction detection device 36, and transmits a search signal and a reflected signal at every fixed angle. An example of a change in the reflection signal level obtained by performing the above-mentioned reception is shown. FIG. 3A shows a change when scanning is performed in one direction, and FIG. 3B shows a search result when the angle of a beam to be searched in the reciprocating direction is shifted by a predetermined angle. In FIG. 3B, the solid line indicates the detection result in the current scan, and the broken line indicates the detection result in the previous scan.

  In the case where the direction of the target is determined based on the detection result as shown in FIG. 3, in FIG. 3 (a), the target is detected only at two angles. Must be determined to be the direction of the target. As shown in FIG. 3B, when data from two scans at different angles are used, the original angle at which the target exists is between the previous B angle and the current A angle. I understand. In the present embodiment, the angle at which the search is performed is shifted from the angle at which the search is performed between the first scan and the second scan even if there is a relatively large interval. , A highly accurate search result can be obtained.

  FIG. 4 shows an example of a relative position change when a search is performed on the target 22 by a plurality of scans. There is generally a speed difference between the target 22 and the vehicle 32. The scanning mechanism 24 scans the antenna 23 in a range of, for example, ± 4 degrees for about 100 ms per scan. Therefore, when the search is performed by two scans, there is a relative movement of about 0.2 seconds between the position of the first vehicle 32 and the position of the final vehicle 32, The target 22 moves. In step a9 of FIG. 2, the Doppler shift frequency is calculated from the relative speed difference based on the above-described equation 4, and the upbeat frequency and the downbeat frequency based on the equations 1 and 2 are calculated based on the calculated Doppler shift frequency. To correct. In step a10, the data corrected according to the change of the Doppler shift frequency is divided for each specific section. In step a11, calculation is performed based on the distance R obtained from Equation 3 and the direction at that time in each specific section. In step a12, it is determined that the portion where the target positions are gathered as a result of the position calculation in step a11 is the road shoulder.

  In the procedure from step a9 to step a12, data that cannot be paired in step a8 is processed as an unnecessary reflector such as a guide rail and used for determining the position of the road shoulder. However, since the unnecessary reflector does not become a major obstacle to the running of the vehicle, the data determined to be unpairable in step a8 may be removed from the processing target and not treated as a target. it can. In this way, the processing load can be reduced.

  FIG. 5 shows a procedure for estimating the position and the relative speed of the target 22 when the vehicle 32 approaches the target 22 at a high speed as the third embodiment of the present invention. After recognizing the target in step b1, in step b2, it is determined whether or not the distance is smaller than a reference. If it is determined that the relative speed has decreased, it is determined in step b3 whether the relative speed is higher than the reference speed. When it is determined in step b2 that the distance is not smaller than the reference distance, or when it is determined in step b3 that the relative speed is not larger than the reference speed, the frequency is determined in step b4 similarly to the normal FM-CW method. The distance to the target 22 and the relative speed are calculated using the data of the rising section and the frequency falling section. When it is determined in step b3 that the relative speed is higher than the reference speed, in step b5, the distance to the target 22 and the relative speed are estimated using only the data in the frequency falling section. When step b4 or step b5 ends, the procedure ends in step b6.

  FIG. 6 shows a change in distance between the upbeat frequency fub and the downbeat frequency fdb when searching for a target by the FM-CW method. From Equations 1 and 2, it can be seen that the difference between the downbeat frequency fdb and the upbeat frequency fub is twice the Doppler shift frequency fd, and from Equation 4, the Doppler shift frequency fd corresponds to the relative speed V. It can be seen that the difference between fdb and fub is proportional to the relative speed V. Therefore, when the relative speed is relatively large, if the distance to the target is small, the upbeat frequency fub becomes considerably small. In the receiving circuit 26 as shown in FIG. 1, it is difficult to perform processing for an extremely low frequency. Therefore, in the present embodiment, when the distance to the target becomes shorter than the reference distance of, for example, d1, the relative speed becomes higher. When the speed is higher than the reference speed V1, the distance to the target and the relative speed are determined using only the downbeat frequency fdb in the frequency falling section without using the upbeat frequency fub in the frequency rising section. As the relative speed, the Doppler shift frequency fd of Expression 4 is obtained using the value obtained by the same FM-CW method as in Step b4 as usual, and the range frequency fr is obtained from the relationship with the downbeat frequency fdb of Expression 2. Is calculated, and the distance R is calculated from Expression 3, and the relative speed V and the distance R are estimated.

  FIG. 7 shows an example of a concept of determining whether or not a stationary object on a road can be stepped over when approaching the object on a road as a fourth embodiment of the present invention. When the height of the target 42 at which the reflection signal 41 from the search signal 40 transmitted from the antenna 23 of the vehicle 32 reflects is relatively higher than the road surface 43, a multipath phenomenon occurs. That is, of the reflected signal 41, a signal directly received by the antenna 23 and a signal reflected by the one circuit surface 43 and then received by the antenna 23 occur, and the reflected signal 41 is received based on a path difference. Causes a phase difference. When the reflected signals 41 cancel each other due to this phase difference, the reflected signal level decreases.

  FIG. 8 shows a difference due to the influence of the height of the target 42 from the road surface 43 when the signal level of the reflected signal 41 due to the distance is expressed as power. FIG. 8A shows a relatively high change in the power of the reflected signal 41 from the target 42. FIG. 8B shows a change in the power of the reflected signal with respect to the target 42 which is relatively low. When the height of the target 42 is high, the fluctuation of the power with respect to the distance is large due to the influence of the multipath.

  In step a22 in FIG. 2, for example, comparison is made between section A and section B in FIG. 8, and in comparison in step a24, comparison is performed between section C and section D in FIG. 8A. Note that an example of the distance between the sections A, B, C, and D is 20 m. Thus, if the power fluctuates due to the influence of the multipath, it can be determined that the height of the target 42 is high and the probability that the vehicle can get over is very small. In the power change when the height of the target 42 shown in FIG. 8B is small, the power increases as the distance gets closer to a certain distance, so that A, B, C, and D in FIG. The conditions of step a22 and step a24 for comparison in the sections respectively corresponding to the sections are not satisfied.

  FIG. 9 shows a procedure for determining whether or not it is possible to step over a stationary object as a fifth embodiment of the present invention. That is, when a stationary object target is detected in step c1, it is determined in step c2 whether or not a section for determining whether or not it is possible to go over is entered based on the distance. In step c3, it is determined whether or not the level of the reflected signal from the target fluctuates depending on the distance and the influence of multipath occurs as in steps a22 and a24 in FIG. When it is determined that there is an influence of multipath, the probability value is increased in step c4. After the probability value is increased in step c4, or after the probability value is not increased in step c3 because there is no influence of multipath, target output is performed in step c5 in the same manner as in step a16 of FIG. Is issued from the warning device 34 shown in FIG. 1, or the braking control is performed by the cruise control device 35 shown in FIG. After the target output in step c5 is completed, or when it is determined in step c2 that it is not the determination section, the procedure ends in step c6. In the present embodiment, the determination section is provided in a plurality of sections as approaching from a long distance side, the determination is performed from an early stage, and the security can be ensured and the reliable determination in the next distance determination can be performed.

  Note that the height of the target can also be detected from the state of occurrence of multipath and the distance to the target.

  FIG. 10 shows a concept of determining the height of a stationary target as a sixth embodiment of the present invention. FIG. 10A shows a state in which the vehicle 32 approaches the targets 44 and 45 existing in front of the road surface 43 in the traveling direction. The target 44 has a lower height from the road surface 43 than the target 45. As shown in FIG. 10 (a), the beam direction 23a from the antenna 23 of the vehicle 32 is widened to some extent, so when the distance to the targets 44 and 45 is relatively large, both the targets The search signal hits 44 and 45, and the reflected signal is received by the antenna 23. As shown in FIG. 10B, when the vehicle 32 approaches the targets 44 and 45, the beam direction 23a of the antenna 23 extends forward from a position spaced from the road surface 43. It will be out of the range of the direction 23a.

  FIG. 11A illustrates a change in the reception power of the reflected signal with respect to the distance when the vehicle 32 approaches the targets 44 and 45 as illustrated in FIG. The solid line indicates the power change of the reflected signal from the low target 44, and the broken line indicates the power change of the reflected signal from the high target 45. Even if the target 45 is high, there may be a case where the height of the target 45 is long enough not to cause the influence of multipath as shown in FIG. In the present embodiment, when approaching the targets 44, 45, the difference in height is recognized from the difference in the reception level due to the difference in height, and the targets 44, 45 are determined based on the mounting position of the antenna 23 and the like. The height of 45 can also be estimated. Whether or not the vehicle 32 can cross the target 44 is determined, for example, by setting a relation map as a threshold value indicating a change in the reception level with respect to the height at which the vehicle 32 can cross the target object, for example, by a one-dot chain line. If the reflected signal level is lower than that, it can be determined that the stepping over is possible. Further, the height of the target 44 can also be estimated based on the threshold value, which is the height at which the object can be stepped over.

  As shown in FIG. 11B, if a plurality of maps having different heights are prepared, it is possible to determine the approximate height of the target from a map in which the falling state is close. In addition, as shown in FIG. 11C, the height can be obtained from the distance R when the reception level falls below a predetermined threshold value P (outside the detection range below the beam) on the short distance side. it can.

  FIG. 12 shows a procedure for determining whether or not it is possible to step over based on the concept of the present embodiment. When a stationary object target is detected in step d1, it is determined in step d2 whether the distance to the stationary object target is shorter than a certain value. When it is determined that the distance is short, it is determined in step d3 whether the reflection signal level is smaller than a predetermined value. If it is not smaller, the possibility that the stationary object target can be stepped over is small, and the probability value is increased in step d4. If the reflection signal level is lower than the fixed value and falls in step d3, there is a high possibility that the stationary object target can be stepped over, and the probability value is reduced in step d5. After step d4 or step d5, in step d6, target output is performed as in step a16 of FIG. At the target output, if the probability value is, for example, 50% or more, an alarm is issued from the alarm device 34 in FIG. 1, and if the probability value further rises to about 70 to 80%, braking is applied by the cruise control device 35. After the target output in step d6 ends, or when it is determined in step d2 that the distance is not smaller than the predetermined value, the procedure ends in step d7. The fixed value for determining the distance in step d2 is, as shown in FIG. 10B, a distance at which the low target 44 is out of the range of the beam direction 23a of the antenna 23.

  The determination process as shown in FIG. 12 is performed after step a25 in FIG. The probability value can be increased or decreased depending on whether or not it is possible to step over, and a more appropriate determination can be made.

  FIG. 13 shows, as a seventh embodiment of the present invention, a procedure of a method of judging a drop in the reflected signal level as shown in FIG. 11 based on a distant level. After detecting a stationary target in step e1, it is determined in step e2 whether the target is an already stored target. If not, the distance to the stationary object target and the reflected signal level are stored in the memory 31 in FIG. 1 in step e3. If the target has already been stored in step e2, the process proceeds to step e4. In step e4, the reflected signal level is compared with the stored signal level. In step e5, it is determined whether or not a certain amount of drop has occurred based on the comparison result. When it is determined that the drop does not exceed a certain value, it is determined in step e6 whether or not the distance is smaller than the reference value. This distance is determined in accordance with the distance at which the target 44 deviates from the beam direction 23a as shown in FIG. If it is determined in step e6 that the distance is smaller than the reference value, the probability value is increased in step e7. If it is determined in step e5 that a certain amount of drop has occurred, the probability value is reduced in step e8. The target output in step e9 is performed with the probability value changed in step e7 or step e8. This target output is performed in the same manner as in step a16 of FIG. When it is determined in step e6 that the distance is not smaller than the reference value, or after the target is output in step e9, the procedure ends in step e10.

  In the present embodiment, the reflected signal level itself is not determined, and in step e4, it is determined whether or not a certain level of drop has occurred, based on the distant reflected signal level. Although the level of the reflected signal changes depending on the material of the target and the like, in the present embodiment, the reflection signal level can be made hard to be affected by the material. In the present embodiment, it is determined whether or not the stationary target can be stepped over by determining whether a certain amount of drop occurs before the distance becomes shorter than the reference value. In other words, the distance at which the drop amount is equal to or greater than a certain value corresponds to the height of the stationary object target, so it is possible to estimate the height of the stationary object target from the distance at which the predetermined amount of drop occurs. It becomes.

  This embodiment is also basically executed following step a25 in FIG. However, it is necessary to store the reflection signal level with respect to the distance in step e2 in each stationary target.

  FIG. 14 shows a concept of determining a stationary target that does not hinder the running of the vehicle as an eighth embodiment of the present invention. If a signboard 46 or the like exists near the road surface 43 on which the vehicle 32 is traveling, the signboard 46 enters the beam direction 23a of the antenna 23 at a relatively long distance as shown in FIG. The signal can be received at an extremely large reflected signal level. As shown in FIG. 14B, when the vehicle 32 approaches the sign 46, the beam direction 23a of the antenna 23 deviates from the sign 46, and the reflected signal level sharply decreases.

  FIG. 15 shows the relationship between the power of the reflected signal and the distance when the vehicle 32 approaches the sign 46 as shown in FIG. In the state shown in FIG. 14A, the power of the reflected signal is relatively large, and rapidly decreases in the state shown in FIG. As shown in FIG. 15, when approaching a high target, the distance at which the power of the reflected signal drops sharply is much longer than the distance at which a drop occurs when approaching a low target. . If the power at a relatively long distance suddenly decreases in the determination at step a20 in FIG. 2, the probability value is reduced at step a21 based on the concept of the present embodiment. In the present embodiment, the height of the lowest part of the target is detected, and it is confirmed that the vehicle can pass through. On the other hand, the determination as to whether or not the above-mentioned stepping is possible is made based on the height of the highest portion.

  Also in the present embodiment, the height of the target can be obtained by using the maps as shown in FIGS. 11B and 11C.

The present invention is capable of the following embodiments.
(1) An on-vehicle radar device mounted on a vehicle and searching for a target around the vehicle is formed so as to have a high gain in a predetermined beam direction, transmits a search signal in the beam direction, and outputs a signal from the target for the search signal. An antenna that receives the reflected signal of the antenna, a scanning unit that performs scanning that changes the beam direction of the antenna within a predetermined range, a direction detection unit that detects a beam direction of the antenna that is changed by the scanning unit, A search control in which a beam direction is repeatedly scanned within the predetermined range, and a target search is performed in a plurality of directions in which the beam direction detected by the direction detection means is at different angles between the repeated scans. Means based on the reflected signal from the target received by the antenna and the probe signal transmitted from the antenna It calculates the distance to the target, based on the beam direction of the antenna which is detected by the distance and direction detection means, vehicle radar device which comprises a target recognition unit for recognizing a target.

  An in-vehicle radar device mounted on a vehicle and searching for a target around the vehicle transmits a search signal from an antenna in a predetermined beam direction and receives a reflected signal from the target. Scanning in which the beam direction of the antenna is changed within a predetermined range by the scanning unit is performed and detected by the direction detecting unit. The scanning control means controls to repeatedly scan the beam direction of the antenna within a predetermined range, and controls to search for a target in a plurality of directions in which the beam direction detected by the direction detecting means is different between the repeated scanning. . The target recognizing means calculates a distance to the search signal based on a reflection signal from the target received by the antenna and a search signal transmitted from the antenna. The target is recognized based on the calculated distance and the beam direction of the antenna detected by the direction detecting means. The beam direction for searching the target is obtained by the scanning control means so as to be in a plurality of different directions for each scan of the antenna. Therefore, if the search results obtained by the plurality of scans are combined, for each finer angle difference, Exploration with high accuracy equivalent to the result obtained by performing the exploration can be performed. Since the angle between searches in one scan need not be as small as the final angle, the direction of the target can be determined with the same accuracy as when the processing speed is increased.

  (2) The target recognizing means performs target recognition based on search results for a plurality of beam directions for each scan, and when the number of beam directions in which reflected signals are received is smaller than a predetermined reference value, An in-vehicle radar device for recognizing a target based on a combination of search results obtained by a plurality of predetermined scans.

  When a sufficient number of search results cannot be obtained in one scan, the target can be recognized based on the search results obtained in a plurality of scans, so that the target recognition accuracy can be improved.

  (3) The target recognizing means calculates a Doppler shift frequency from a frequency shift caused by movement of the target based on a search result obtained by the plurality of scans, and calculates a reflection signal to be combined for target recognition according to the calculation result. An on-vehicle radar device characterized in that it is changed by changing.

  It is possible to perform high-accuracy recognition by combining target search results in consideration of a time lag between a plurality of scans.

  (4) The target recognizing means recognizes, as a reflected signal from an undesired object, a reflected signal of a frequency that is out of the target of combination according to the calculated result, as a reflected signal from an undesired object. An in-vehicle radar device not to be handled.

  Reflected signals of frequencies that cannot be combined among multiple search results are recognized as unnecessary reflected objects and are not treated as reflected signals from the target, so that the processing load is not allocated to targets that do not actually need to be careful. In this way, it is possible to perform a focused process on a target that requires attention.

  (5) The search for the target is performed by an FM-CW method, and the target recognizing means obtains, from the search results, peak data obtained from a reflection signal of a frequency that is not subject to a combination according to the calculation result. The on-vehicle radar device according to claim 1, wherein a Doppler shift corresponding to the own vehicle speed is subtracted between a frequency rising section and a falling section of the FM-CW system to calculate a distance and a direction.

  Even if the search result is not a target for combination corresponding to a specific target, the distance and direction are calculated by subtracting the Doppler shift of the own vehicle speed between the frequency rise section and the fall section of the FM-CW method. Therefore, the position of the exploration target can be obtained effectively.

  (6) The target recognizing means recognizes the calculation result of the distance and the direction as data on an unnecessary reflector, obtains a position where the unnecessary reflectors gather from the distance and the direction, and determines the position as a road shoulder. An on-vehicle radar device, comprising:

  The calculation results based on the search results that could not be combined are recognized as data on unnecessary reflectors, and the position where unnecessary reflectors gather is determined to be the shoulder of the road. , And the processing load can be reduced.

FIG. 2 is a block diagram showing a schematic electrical configuration of the on-vehicle radar device 21 used in each embodiment of the present invention. 5 is a flowchart illustrating an operation procedure of the target recognition circuit 30 according to the first embodiment of the present invention. FIG. 13 is a diagram illustrating a concept of detecting a direction of a target by a plurality of scans as a second embodiment of the present invention. FIG. 9 is a diagram showing a concept of considering a relative movement amount of a target when using data obtained by a plurality of scans. 13 is a flowchart illustrating a procedure for estimating a distance and a relative speed with respect to a target approaching at a high relative speed according to a third embodiment of the present invention. 9 is a graph showing a reason for estimating a distance and a relative speed using a frequency falling section for a target approaching at a high relative speed. FIG. 16 is a diagram illustrating a concept of determining whether or not a vehicle can be overtaken based on whether or not a reception level of a reflected signal fluctuates due to the influence of multipath as a fourth embodiment of the present invention. 9 is a graph showing a state where a difference in the influence of multipath occurs according to a difference in target height. It is a flow chart which shows a procedure as a 5th form of the present invention which judges whether it is possible to step over a stationary object target in a plurality of sections when approaching from a long distance side. FIG. 16 is a diagram illustrating a principle as a sixth embodiment of the present invention, in which it is possible to determine whether or not it is possible to step over a stationary object target based on a drop in a reflected signal level when approaching. 9 is a graph showing a relationship between a distance when approaching a stationary target that can be stepped over and a reflected signal level. 11 is a flowchart illustrating a procedure of another concept for determining whether or not a stationary target can be stepped over using the concept illustrated in FIG. 10. 21 is a graph showing another concept of determining whether or not a stationary object target can be stepped over from a level of a reflected signal at a long distance and a level drop amount when approaching as a seventh embodiment of the present invention. FIG. 28 is a diagram illustrating a concept of determining that a stationary object target is at a position higher than a position where a vehicle travels, such as a signboard, as an eighth embodiment of the present invention. 15 is a graph illustrating a change in a reflection signal level with respect to a stationary object at a high position as shown in FIG. 14 depending on a distance. It is a block diagram which shows the schematic electrical structure of the conventional vehicle-mounted radar apparatus. 6 is a graph showing the operation principle of the FM-CW radar device.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 21 On-vehicle radar device 22 Target 23 Antenna 23a Beam direction 24 Scanning mechanism 25 Transmission circuit 26 Receiving circuit 29 Target detection circuit 30 Target recognition circuit 31 Memory 32 Vehicle 33,43 Road surface 34 Warning device 35 Cruise control device 36 Direction detection device 40 Search signal 41 reflected signal 44,45 target 46 signboard

Claims (13)

In an on-vehicle radar device mounted on a vehicle and searching for a target around the vehicle,
An antenna formed to have a high gain in a predetermined beam direction, transmitting a search signal in the beam direction, and receiving a reflected signal from a target for the search signal;
The distance to the target is calculated based on the reflected signal from the target received by the antenna and the search signal transmitted from the antenna, and the target is recognized based on the distance and the beam direction of the antenna detected by the direction detecting means. And a target recognition means for judging the height of a stationary target by determining whether or not the influence of multipath is reflected in a change in the reflected signal level due to the distance in a specific frequency range. On-board radar equipment.   2. The target recognizing means judges that the target can be stepped over when the level of the reflected signal from the stationary target sharply decreases during the approach. In-vehicle radar device.   The target recognizing means has, in advance, data indicating a change in a threshold value of the reflection signal level with respect to the distance with respect to the stationary target to be recognized, and when the reflection signal level from the stationary target becomes smaller than the threshold value within a predetermined distance range. 8. The on-vehicle radar device according to claim 7, wherein it is determined that the target can be stepped over. In an in-vehicle radar device mounted on a vehicle and searching for a target around the vehicle,
An antenna formed to have a high gain in a predetermined beam direction, transmitting a search signal in the beam direction, and receiving a reflected signal from a target for the search signal;
The distance to the target is calculated based on the reflected signal from the target received by the antenna and the search signal transmitted from the antenna, and the target is recognized based on the distance and the beam direction of the antenna detected by the direction detecting means. Performing, for a stationary target to be recognized, has data indicating a threshold of the reflection signal level with respect to the distance in advance, and based on the distance at which the reflection signal level from the stationary target is smaller than the threshold, the height of the target is determined. An on-vehicle radar device comprising: target recognition means for determining.   5. The on-vehicle radar device according to claim 4, wherein the target recognizing means determines whether or not the stationary target can be stepped over based on a state in which the reflected signal level decreases as the distance approaches. In an on-vehicle radar device mounted on a vehicle and searching for a target around the vehicle,
An antenna formed to have a high gain in a predetermined beam direction, transmitting a search signal in the beam direction, and receiving a reflected signal from a target for the search signal;
The distance to the target is calculated based on the reflected signal from the target received by the antenna and the search signal transmitted from the antenna, and the target is recognized based on the distance and the beam direction of the antenna detected by the direction detecting means. And a target recognizing means for judging the height of the stationary target based on the distance at which the reflected signal level suddenly decreases with approach. In an on-vehicle radar device mounted on a vehicle and searching for a target around the vehicle,
An antenna formed to have a high gain in a predetermined beam direction, transmitting a search signal in the beam direction, and receiving a reflected signal from a target for the search signal;
Target recognition means for calculating the distance to the target based on the reflection signal from the target received by the antenna and the search signal transmitted from the antenna, and recognizing the target based on the calculation result,
The target recognizing means, when recognizing a target that is stationary at a distance more than a predetermined distance, when the level of the reflected signal at the time of recognition is larger than a predetermined reference and is closer than the vehicle position at the time of recognition. An in-vehicle radar device, which recognizes that the target is not a target whose height should be cautious with respect to the running of the vehicle when the level of the level of the reflected signal is large.   The on-vehicle radar device according to claim 1, wherein the height of the target is a height of a highest portion of the target.   9. The on-vehicle radar device according to claim 8, wherein the target recognizing means determines whether or not the target can step over based on the determined height.   8. The on-vehicle radar device according to claim 4, wherein the height of the target is a height of a lowest part of the target.   The in-vehicle radar device according to claim 10, wherein the target recognition unit determines whether the target can pass through based on the determined height.   The target recognizing means performs the determination of the height of the target in a plurality of sections according to the distance from the target, and a predetermined warning and / or braking signal based on the determination result for each section. The in-vehicle radar device according to any one of claims 8 to 11, which derives: The exploration of the target is performed by the FM-CW method,
2. The target recognizing means, when judging that the relative speed with respect to the target is higher than the reference speed, estimates the distance to the target and the relative speed using only the data of the frequency descending section. 13. The on-vehicle radar device according to any one of to 12.

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