JP2019007926A - Detector - Google Patents

Abstract

To provide a detector with which it is possible to more accurately detect a speed of an own vehicle.SOLUTION: Provided is a detector 1 mounted on a vehicle body 2, for radiating a transmission wave to ahead of the vehicle body and receiving a reflected wave of the transmitted wave to detect a target, as well as estimating a speed of an own vehicle, the detector 1 detecting, in a first reference plane that includes a reference line extending forward of the vehicle body from the detector, with the detector as a starting point, first targets A-I symmetrically with respect to the reference line that are present in a range of a first angle width, and estimating the speed of the own vehicle on the basis of the Doppler shift of reflected waves from second targets A-G among the first targets that exist in a range of a second angle width, symmetrically with respect to the reference line in the first reference plane, with the detector as a starting point.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a detection device that is mounted on a body of an automobile or the like and detects the vehicle speed based on a Doppler shift.

  There is known a detection device that includes a radar for lateral monitoring, identifies a stationary object, and detects the vehicle speed based on the direction and relative speed of the stationary object (for example, Patent Document 1). The detection device of Patent Document 1 radiates electromagnetic waves from a radar to a search area set on the left and right sides of the vehicle body, and measures the frequency of a reflected wave reflected by a stationary object in the search area. Furthermore, the detection device calculates the relative speed of the stationary object with respect to the vehicle body based on the Doppler shift of the frequency of the reflected wave, and detects the vehicle speed.

JP 2010-43960 A

  The Doppler shift depends on the component of the relative speed vector of the object with respect to the vehicle body in the direction connecting the object and the vehicle body, that is, the line-of-sight speed. Since the line-of-sight speed is smaller when the object is on the left and right sides than when the object is in front of the vehicle body, the Doppler shift is small in the detection device of Patent Document 1, and the error in the detected vehicle speed is large. Become. Therefore, there is a problem that it is difficult to accurately detect the vehicle speed.

  In view of the above background, it is an object of the present invention to provide a detection device that can detect the vehicle speed more accurately.

In order to solve the above problem, the vehicle is mounted on the vehicle body (2), radiates a transmission wave to the front side of the vehicle body, receives a reflected wave of the transmission wave, detects a target, and estimates the vehicle speed. In the first reference plane (S ₁ ) including the reference line (L) extending from the detection device to the front of the vehicle body, the detection device (1) is symmetrical about the reference line with the detection device as a starting point. A first target (A to I) within a range (P) of a first angular width (δ ₁ ) is detected, and the detection device is used as a starting point on the first reference plane of the first target. Detecting the own vehicle speed based on the Doppler shift of the reflected wave from the second target (A to G) within the range (Q) of the second angular width (δ ₂ ) symmetrically with respect to the reference line An apparatus is provided.

  According to this aspect, when the target located in front of the vehicle body is used, the Doppler shift increases and the error of the own vehicle speed decreases, so that the accuracy of the estimated own vehicle speed improves.

  In the above aspect, the first reference plane may be parallel to the vehicle width direction.

  According to this aspect, since many targets on the running surface of the vehicle body can be used for estimating the host vehicle speed, the accuracy of the host vehicle speed is improved.

  In the above aspect, the first reference plane may be parallel to the vertical direction.

  According to this aspect, since the target positioned in the vertical direction of the vehicle body is often fixed to the ground, the accuracy of the host vehicle speed is improved.

  Further, in the above aspect, based on the Doppler shift of the reflected wave from the plurality of second targets, a line-of-sight speed of the second target with respect to the detection device is calculated, and each of the second targets is calculated. On the other hand, a value obtained by dividing the line-of-sight speed by a cosine of an angle formed by a straight line passing through the second target and the detection device and a straight line extending forward through the detection device is defined as a provisional velocity. The second target whose difference between the average value and the temporary speed is equal to or less than a predetermined speed threshold is selected as a third target (A to E), and the vehicle speed is determined based on the temporary speed of the third target. It is good to estimate.

  According to this aspect, since the vehicle speed can be estimated by excluding the target moving with respect to the ground, the accuracy of the vehicle speed is improved.

  In the above aspect, when the difference between the temporary speed corresponding to each of the second targets and the estimated vehicle speed is larger than a predetermined moving body speed threshold, the second target is It is good to label as a moving body which moves with respect to the ground, and not to select the second target labeled as the moving body as the third target.

  According to this aspect, since the target moving with respect to the ground is surely excluded, the accuracy of the estimated vehicle speed is improved.

In the above aspect, the detection device further includes the reference line, and is symmetrical about the reference line with the detection device as a starting point on a second reference surface (S ₂ ) different from the first reference surface. , A target within the range of the third angular width (δ ₃ ) is detected, and the fourth angular width (δ ₄ ) is symmetric about the reference line with the detection device as a starting point on the second reference plane. The host vehicle speed may be estimated based on the Doppler shift of the reflected wave from the target within the range.

  According to this aspect, since the estimation of the own vehicle speed is based on the target located in front of the vehicle body, the accuracy of the estimated own vehicle speed is improved.

  According to the above configuration, it is possible to provide a detection device that can detect the host vehicle speed more accurately.

Schematic diagram of a vehicle equipped with a detection device according to the present embodiment The perspective view at the time of driving | running | working of the vehicle carrying the detection apparatus which concerns on this invention Flow chart of own vehicle speed estimation process (A) The movement of the vehicle body and the stationary object when viewed from the ground, (B) The movement of the vehicle body and the stationary object when viewed from the vehicle body, and (C) The moving object when viewed from the vehicle body. Explanatory diagram of the movement of things Explanatory drawing of the area | region where each of the 1st target and 2nd target in a 2nd reference plane is contained Figure showing the dependence of the temporary speed error on the angle θ A graph showing the dependence of error rate δ on angle θ Flow chart of own vehicle speed estimation process according to another embodiment

  Hereinafter, embodiments of a detection apparatus according to the present invention will be described with reference to FIGS. The detection device 1 according to the present invention is a radar mounted on a vehicle 2, which radiates electromagnetic waves in front of the vehicle body 3, receives reflected waves reflected from an object located in front of the vehicle body 3, This is a device for identifying a target based on a reflected wave signal and grasping a relative positional relationship between the vehicle body 3 and the target. The detection device 1 detects a target located in the vicinity of the vehicle body 3, for example, in the case of rainy weather with poor visibility, and compares the relative speed between the target and the vehicle body 3 with the host vehicle speed so that the target is detected. In order to determine whether the vehicle is moving, the host vehicle speed is estimated.

  As shown in FIG. 1, the detection device 1 includes a transmission device 5 that is mounted on the front end of the vehicle body 3 and radiates a transmission wave around the front of the vehicle body. The transmission device 5 includes a transmission antenna that radiates electromagnetic waves in a predetermined direction of a predetermined frequency between a microwave band and a millimeter wave band (several hundred GHz to several THz) as a transmission wave based on an input signal; And a scanning device that changes the direction of the electromagnetic wave radiated from the transmission antenna in the vertical direction and the vehicle width direction with respect to the front of the vehicle body 3. In the present embodiment, the transmission device 5 includes a phased array antenna, the transmission antennas are arranged in a grid pattern on the front surface of the vehicle body 3, and the scanning device controls the phase of electromagnetic waves radiated from the transmission antenna. By controlling the phase of the electromagnetic wave, the radiation direction of the electromagnetic wave radiated from the transmitting antenna changes.

  The detection device 1 further includes a reception device 7 that is mounted on the front end of the vehicle body 3 and receives a reflected wave from an object existing around the front of the vehicle body. The receiving device 7 is a receiving antenna that detects a reflected wave, for example, and outputs a received signal. The receiving device 7 can detect a reflected wave from an object within a detectable distance R (up to several tens of meters). The receiving device 7 is mounted at a position adjacent to the transmitting device 5 at the front end of the vehicle body 3, and the distance (up to several cm) between the transmitting device 5 and the receiving device 7 is sufficiently smaller than the detectable distance R. Therefore, in the following, it can be considered that the position of the transmission device 5 and the position of the reception device 7 are substantially the same.

  The detection device 1 further includes a control device 10 connected to the transmission device 5 and the reception device 7. The control device 10 includes a central processing unit (CPU) mounted on the front portion of the vehicle body 3, a memory, and a predetermined input / output interface for exchanging signals with the transmission device 5 and the reception device 7. The control device 10 inputs a signal to the transmission device 5, and controls the transmission device 5 to emit an electromagnetic wave having a predetermined intensity and a predetermined frequency (transmission frequency) in a predetermined direction. Furthermore, the control apparatus 10 detects the intensity | strength and frequency (reception frequency) of the reflected wave reflected by the target object in the radiation | emission direction and received by the receiver 7.

  The control device 10 radiates electromagnetic waves in front of the vehicle body 3, detects the reflected wave, and performs own vehicle speed estimation processing for estimating the own vehicle speed. Below, with reference to the flowchart described in FIG. 3, the own vehicle speed estimation process will be described.

In step ST1, the control device 10 causes the transmission device 5 to emit an electromagnetic wave having a predetermined transmission frequency from the transmission antenna, and sweeps the radiation direction in the vehicle width direction. When the sweep in the vehicle width direction is completed, the radiation direction is gradually changed in the vertical direction, and the sweep is performed again in the vehicle width direction. By repeating this, the radiation direction of the electromagnetic wave causes the transmission device 5 to be centered on a reference line L that is a straight line that extends forward of the vehicle body 3 (black arrow in FIG. 1) through the transmission device 5 (reception device 7). As a starting point, the angle width Φ _W in the vehicle width direction and the angle width Φ _{H in} the up-down direction are varied.

Control device 10, simultaneously with the sweep of the radiation direction of the electromagnetic wave to obtain the relationship between the intensity of the received reflected wave by the receiving device 7 and its radial, the intensity maps of the vehicle width direction phi _W and the vertical direction phi _H create. At the same time, the control unit 10, by multiplying the electromagnetic wave signal received by the receiving device 7 for FFT, obtains the reception frequency of the reflected wave in each direction, the frequency of the vehicle width direction phi _W and the vertical direction phi _H Create a map. However, in the present embodiment, the control device 10 sets the frequency at which the intensity is maximum when the reflected wave signal is multiplied by the FFT as the reflected wave reception frequency.

The first region X (FIG. 1), which is the target detection range of the control device 10, is inside a sphere whose radius around the receiving device 7 is a detectable distance R, and starts from the receiving device 7. Centering on the reference line L, it becomes the inside of the area | region of angle width (PHI) _W and angle width (PHI) _{H in} a vehicle width direction and an up-down direction, respectively. In this way, since the radiation direction of the transmission wave changes in the vertical direction and the vehicle width direction, a target for estimating the host vehicle speed is more than in the case where the sweep in the radial direction is only in the vertical direction or the vehicle width direction. More can be selected, and the accuracy of the vehicle speed is improved.

Based on the created intensity map, the control device 10 has an area (solid angle) for φ _W and φ _H whose reflected wave intensity on the intensity map is greater than or equal to a predetermined intensity threshold and greater than or equal to the intensity threshold. ) Is a predetermined solid angle threshold or more, and an object corresponding to the area is set as the first target. Thereafter, the control device 10 averages the received frequencies detected in each of the regions corresponding to the first target with a weight corresponding to the intensity of the reflected wave based on the frequency map. Record the frequency of the reflected wave from the mark.

The angle widths Φ _W and Φ _H need to be set sufficiently large so that a plurality of first targets are selected. The angular width Φ _{W in the} vehicle width direction is set to be at least 20 degrees and not more than 300 degrees, and is preferably a predetermined value of not less than 40 degrees and not more than 300 degrees. In the present embodiment, the angular width [Phi _W is set to 60 degrees. The vertical angle width Φ _H is set to be at least 5 degrees and 180 degrees, and is preferably a predetermined value of 5 degrees to 100 degrees. In the present embodiment, the angular width [Phi _H is set to be 40 degrees.

  In the case shown in FIG. 2, the intensity of the reflected wave from the area indicated by the broken line is large, and the traffic light A, electric light B, guide sign C, manhole D, street tree E, pedestrian F, corresponding to each area, A pedestrian G, an electric lamp H, and a roadside tree I are detected as first targets. In general, since there are many stationary objects on the traveling surface on which the vehicle 2 travels, many stationary objects are included in the first target. In the case of FIG. 2, A to E, H, and I correspond to stationary objects. When the selection of the first target is completed, the control device 10 executes Step ST2.

  In step ST2, the control device 10 geometrically determines, for each of the first targets in step ST1, based on the position of the first target on the intensity map, the reference line L, the receiving device 7, An angle θ formed with a straight line connecting the first target is calculated. More specifically, in the present embodiment, the straight line connecting the receiving device 7 and the first target is the position of the center of gravity of the region corresponding to the receiving device 7 and the first target (the center of gravity on the intensity map). Defined as a straight line connecting positions). In the present embodiment, it is assumed that the traveling direction of the vehicle body 3 is equal to the front of the vehicle body 3 (the direction of the arrows in FIGS. 1 and 2).

したがって、第１物標からのシフト量Δνを用い、視線速度ｖ_ｒを求めることができる。次に、制御装置１０は、第１物標のそれぞれに対して、第１物標の受信装置７に対する視線速度を第１物標に対応する角度θの余弦ｃｏｓθで割った仮速度ｖ_１を算出し、ステップＳＴ２を完了する。 Further, in step ST2, the control device 10 first obtains the line-of-sight velocity for the receiving device 7 using the reception frequency for each of the first targets. When the first target is moving relative to the vehicle body 3 (receiving device 7), the reception frequency is shifted to a value different from the transmission frequency (Doppler shift) due to the Doppler effect. The receiving device 7 and the first target are connected with the receiving frequency ν (Hz), the transmitting frequency ν ₀ (Hz), the shift amount Δν (Hz), and the velocity vector of the relative speed of the first target with respect to the receiving device 7. The relationship between the component in the linear direction, that is, the line-of-sight velocity (radial velocity) v _r (km / h) of the first target with respect to the receiving device 7 is the light velocity c (= 3.0 × 10 ⁸ m / s = 1.1). × 10 ⁹ m / h), and expressed by the following formula (1).

Therefore, the line-of-sight velocity v _r can be obtained using the shift amount Δν from the first target. Next, the control device 10 calculates, for each first target, a provisional velocity v ₁ obtained by dividing the line-of-sight velocity of the first target with respect to the receiving device 7 by the cosine cos θ of the angle θ corresponding to the first target. Calculate and complete step ST2.

For temporary speed _{v 1} obtained in step ST2, the will be described with reference to FIG. 4 (A) ~ (C) . First, consider a case where the first target is stationary with respect to the ground and the vehicle body 3 is moving forward with respect to the ground at a speed v (speed vector V) (FIG. 4A). As shown in FIG. 4B, the angle θ is formed by the reference line L and a straight line connecting the receiving device 7 and the first target, and the first target moves backward as viewed from the vehicle body 3. It moves at a speed v (velocity vector -V). Therefore, the line-of-sight speed of the first target when viewed from the receiving device 7 is v cos θ, and the temporary speed v ₁ obtained in step ST2 is equal to the actual host vehicle speed v.

However, as shown in FIG. 4C, the vehicle body 3 moves with respect to the ground at the speed v (speed vector V) in FIG. 4C, and the first target moves with respect to the ground with the speed vector W. When the vehicle is moving, the velocity vector of the first target when viewed from the vehicle body 3 is represented by a velocity vector U (= W−V) that is the difference between the velocity vector W and the velocity vector V. Therefore, the line-of-sight speed of the first target with respect to the receiving device 7 is different from vcos θ, and the temporary speed v ₁ obtained in step ST2 is different from the actual own vehicle speed v. In the present invention, in the following steps, specifically, in steps ST3 to ST5, the control device 10 estimates the host vehicle speed by performing statistical processing for selecting a stationary one from the plurality of first targets. To do.

Controller 10, in step ST3, the from the first target, the absolute value of the corresponding angle theta is the first target at an angle threshold theta _th following regions Z, is extracted as the second target. Region Z is a straight line extending from the receiver 7 to the front and to the axis, the receiving device 7 and the apex, the apex angle corresponds to the inside of the area Z of the cone is a 2 [Theta] _th. Further, the angle threshold θ _th is set to be smaller than 1/2 of the angle widths Φ _W and Φ _H (θ _th <Φ _W / 2 and θ _th <Φ _H / 2). In the present embodiment, 15 degrees is used as the angle threshold.

1, the first reference surface S ₁ parallel to the vehicle width direction including the reference line L is shown as a solid line. The first target is located within the region P where the angular width is the first angular width δ ₁ symmetrically with respect to the reference line L, starting from the position of the receiving device 7 on the first reference plane S ₁ . The second target is the first reference surface S on _1, starting from the position of the receiving apparatus 7, symmetrically about the reference line L, the angular width is within the second angle range [delta] ₂ and a region Q . Since the first angular width δ ₁ is equal to Φ _W and the second angular width δ ₂ is equal to 2θ _th , the second angular width δ ₂ is smaller than the first angular width δ ₁ . Accordingly, in step ST3, the control unit 10, from the first target object in the first reference surface S _1, and selects the second target to include many target object angle θ is small, the group of the second target Is configured.

Further, as shown in FIG. 5, on the second reference plane S < _b > ₂ that is parallel to the vertical direction including the reference line L, the first target is symmetrical with respect to the reference line L with the position of the receiving device 7 as a starting point. in, is inside the region where the angular width is the third angular width [delta] _3, the second target is starting from the position of the receiving apparatus 7, symmetrically about the reference line L, the angular width is fourth angular width [delta] ₄ It is inside the area. Since the third angular width δ ₃ is equal to Φ _H and the fourth angular width δ ₄ is equal to 2θ _th , the fourth angular width δ ₄ is smaller than the third angular width δ ₃ . Therefore, in step ST3, the control unit 10, from the first target object in a second reference plane S _2, select the second target to include many target object angle θ is small, the group of the second target Is configured.

  In the present embodiment, as shown in FIGS. 1 and 5, the first target and the second object are not limited to the vehicle width direction and the horizontal direction, but also on a reference plane in any direction including the reference line L. Each of the targets is located in a region where the angle width is a predetermined value symmetrically with respect to the reference line L, starting from the position of the receiving device 7, and the angle width that defines the region of the second target is the first target. Smaller than Therefore, the second target is selected from the first target so as to further include a target having a small angle θ.

  Considering the case as shown in FIG. 2, in step ST3, the lamp H located on the left side of the vehicle body 3 and the roadside tree I located on the right front are not extracted as the second target, but A traffic light A, an electric lamp B, a guide sign C, a manhole D, a roadside tree E, and pedestrians F and G, which are located at, are extracted as second targets. Then, the control apparatus 10 performs step ST4.

Controller 10, in step ST4, after obtaining the average value v ₂ of the provisional velocity v ₁ of the second target, from the second target, the provisional velocity v ₁ corresponding to the average value v ₂ A second target whose absolute value of difference is equal to or smaller than a predetermined speed threshold v _th is selected as a third target.

Step ST4 is intended to extract a stationary object from the second target. In FIG. 2, the second target is traffic light A, electric light B, guide sign C, manhole D, street tree E, pedestrians F and G, many of which (A to E in FIG. 2) are against the ground. And is stationary. Therefore, the ratio of the still contained in the second target is sufficiently larger than the ratio of the moving average value v ₂ of the provisional velocity v ₁ of the second target is made substantially equal to the vehicle speed. On the other hand, like the pedestrians F and G in FIG. 2, the temporary speed v ₁ of the second target that is not stationary with respect to the ground is greatly different from the average value v ₂ . Thus, in step ST4, the control unit 10, from the group of the second target, the absolute value of the difference between the temporary speed v ₁ and the average value v ₂ is equal to or less than the speed threshold value v _th second target (FIG. 2 A to E) can be selected as the third target, so that a stationary object can be extracted from the second target as the third target. After selecting the third target, the control device 10 executes Step ST5.

In step ST5, the control device 10 calculates an average value v _av of the temporary speed corresponding to each of the third targets (A to E in FIG. 2), and estimates the average value v _av of the temporary speed as the own vehicle speed. To do. Thereafter, the control device 10 completes the own vehicle speed estimation process. In step ST4, since the third target selects a target that is substantially stationary with respect to the ground from the second target, the estimated own vehicle speed (the average value v _{av of the} temporary speed) is the actual own vehicle speed. Is almost equal to Thus, since the own vehicle speed is estimated using the third target that includes a larger number of targets with a lower speed relative to the ground, the accuracy of the estimated own vehicle speed is improved.

Next, the effect of the detection apparatus 1 configured as described above will be described. The measurement of the angle θ has a measurement error Δθ. Since the temporary speed v ₁ obtained in step ST2 is calculated by dividing the line-of-sight speed by the cosine cos θ of the angle θ, an error Δv ₁ also occurs in the temporary speed v ₁ . In FIG. 6, when the vehicle body 3 travels at 60 km / h and the measurement error Δθ of the angle θ is 1 degree, the temporary speed error Δv ₁ obtained for the stationary target at the position of the angle θ is shown. A solid line indicates a temporary speed error Δv ₁ obtained for a stationary target at an angle θ when Δθ is 3 degrees. The temporary speed error Δv ₁ is expressed by the following equation.

According to FIG. 6, it can be confirmed that the smaller the angle θ, the smaller the error Δv ₁ of the provisional speed v ₁ . Since the error of the own vehicle speed estimated to be smaller when the error Δv ₁ is reduced, the Doppler shift of a target having a small angle θ is preferably used to reduce the estimated error of the own vehicle speed. In the present invention, in step ST3, a group of second targets that are located in front of the receiving device 7 from the first target and include more targets having a small angle θ are configured, and the second target group. Since the third target is extracted from and the own vehicle speed is estimated, the accuracy of the estimated own vehicle speed is improved.

In addition, when the control device 10 selects the second target from the first target in step ST3, the control device 10 determines whether the angle θ corresponding to each of the first targets is equal to or smaller than the angle threshold θ _th. Yes. Therefore, the process (step ST3) of selecting from the first target so as to include more targets that are located in front of the receiving device 7 and have a small angle θ is simple.

The angle threshold value _θth is determined based on the measurement error Δθ of the angle θ and the accuracy required for the host vehicle speed. When the measurement error Δθ of the angle θ is 3 degrees, the own vehicle speed is 60 km / h, and the accuracy required for the estimated own vehicle speed is 3.5 km / h or less, based on the broken line in FIG. The angle threshold θ _th is set to a value between 0 degrees and 45 degrees. The accuracy required for the estimated host vehicle speed is at least 6.0 km / h, preferably 1.0 km / h. For example, in the present embodiment, the measurement error Δθ is 3 degrees, the host vehicle speed is 60 km / h, and the accuracy required for the host vehicle speed is 1.0 km / h or less. In addition, the angle threshold value θ _th is set to 15 degrees. In this way, by referring to FIG. 6, the upper limit value of the angle threshold value _θth can be determined based on the measurement error Δθ of the angle θ so as to satisfy the accuracy required for the host vehicle speed.

となる。測定誤差Δθが２度であるときに、誤差率δを５％以下とする場合は、図７に基づいて、角度閾値θ_ｔｈは４５度以下に設定される。誤差率δは、少なくとも１０％以下であり、０．０２％以下であることが好ましい。 Further, based on the ratio δ (error rate) of the difference between the true (actual) own vehicle speed and the own vehicle speed obtained when there is a measurement error Δθ in the measurement of the angle θ, the angle threshold value θ _th may be obtained. When the true host vehicle speed is u, the line-of-sight speed of the stationary target at the angle θ is ucos θ. The required own vehicle speed is expressed as u cos θ / (cos (θ + Δθ)) when the target is measured at the position of the angle θ + Δθ by the measurement error Δθ. Therefore, δ is

It becomes. If the error rate δ is 5% or less when the measurement error Δθ is 2 degrees, the angle threshold θ _th is set to 45 degrees or less based on FIG. The error rate δ is at least 10% or less, and preferably 0.02% or less.

Further, based on the own vehicle speed estimated by other means (for example, the rotational speed of the wheel) or the own vehicle speed estimated a predetermined time ago so that the error required for the own vehicle speed becomes constant, the angle threshold θ You may set to change _th . For example, when the host vehicle speed estimated by other means is 10 km / h so that the error of the host vehicle speed is always 2.0 km / h or less, the angle threshold _θth is set to 68 degrees or less. When the vehicle speed estimated by the above is 40 km / h, the angle threshold _θth may be set to 45 degrees or less.

As the angle threshold _θth approaches 0, the estimated error in the vehicle speed becomes smaller. However, when the angle threshold value _θth approaches 0, the transmission wave is radiated only in front of the vehicle body 3. Therefore, the number of detected targets decreases, and it becomes difficult to estimate the host vehicle speed. Therefore, a transmission wave radiated in a direction that forms an angle of the angle threshold _θth with respect to the reference line L reaches the outside of the lane in which the vehicle 2 travels or reaches a sign / signal, and the reflected wave is detected by the receiving device 7. It is preferable. The angle threshold θ _th is set to a predetermined lower limit or more determined by the width of the lane, the height of the sign or signal, and the detectable distance R of the receiving device 7, and the lower limit is at least 5 degrees, preferably 10 It is good to set more than degree.

  Although the description of the specific embodiment is finished above, the present invention is not limited to the above embodiment and can be widely modified. In the above embodiment, as shown in FIG. 1, the direction of the electromagnetic wave radiated from the transmission device 5 is configured to change in the vertical direction and the vehicle width direction with respect to the front of the vehicle body 3. It is not necessary to change in the width direction and the up-down direction, and for example, it may be configured to change only in either the vehicle width direction or the up-down direction.

  When the radiation direction is changed only in the vehicle width direction, it is not necessary to change the radiation direction in the vertical direction, so that the own vehicle speed estimation process is simplified. Furthermore, since many targets located on the traveling surface of the vehicle body 3 can be detected and the vehicle speed can be estimated based on more targets, errors in the vehicle speed can be suppressed. . Even when the radiation direction is changed to the vehicle width direction, a plurality of transmission antennas and reception antennas (for example, one at each of the front, rear, left and right ends of the vehicle body 3) are arranged on the vehicle body 3 and combined to radiate. You may comprise so that a direction can be swept more widely with respect to the vehicle body 3 with respect to the vehicle width direction.

  When the radiation direction is changed to the vertical direction only, it is possible to detect a target stationary on the ground such as a sign or a manhole existing in the front vertical direction of the vehicle body 3, thereby suppressing an error in the own vehicle speed. it can.

In the above embodiment, in step ST4, had been selected as the third target using the average value v ₂ of the provisional velocity v _1, it is not limited to the average value, mode value, and the median like Any of the representative values may be included. For example, the configuration in step ST4, the second target object, such that the difference of the provisional speed v ₁ and the mode of temporary speed v ₁ selects the following second target speed threshold v _th a third target May be.

In step ST5, the control device 10 estimates the average value v _av of the temporary speed obtained from the third target as the _host vehicle speed, but is not necessarily limited to the average value, and is obtained from the third target, for example. A representative value such as a mode value or a median value of the provisional speed may be estimated as the own vehicle speed. Further, the control unit 10, in step ST4, it constituted the third target by selecting the second target from a group of a plurality of second target, the temporary speed v ₁ and the average value v ₂ It is also possible to select one second target having an absolute value of the difference between and the speed threshold value v _th or less as a third target. At this time, the control apparatus 10 estimates the temporary speed of the one third target as the own vehicle speed.

  In the above embodiment, assuming that the traveling direction of the vehicle body 3 is equal to the front of the vehicle body (the direction of the arrow in FIGS. 1 and 2), the reference line L extending from the reception device 7 to the front of the vehicle body 3, and the reception device The vehicle speed is estimated based on the angle θ formed by the straight line connecting the object 7 and the object, but the straight line extending in the traveling direction of the vehicle body 3 from the receiving device 7 and the straight line connecting the receiving device 7 and the object The vehicle speed may be estimated based on the angle formed by At this time, the detection device 1 may further include a steering angle sensor that detects the direction of the wheel with respect to the front of the vehicle body 3, and obtain the traveling direction of the vehicle body 3 based on the steering angle detected by the steering angle sensor. .

As shown in FIG. 8, in addition to step ST1~ST5 of the above embodiment, vehicle speed estimation process, after step ST5, the vehicle speed estimated in the provisional velocity v ₁ and step ST4 of the second target When the difference is larger than a predetermined moving body speed threshold value, a step ST6 of labeling the second target as a moving body may be included. In this case, in step ST4, after obtaining the average value v ₂ of the provisional velocity v ₁ corresponding to the second target object is not a moving body, of the no second target is mobile, the temporary speed v ₁ and the average value The second target whose absolute value of the difference from v ₂ is equal to or less than the speed threshold v _th may be selected as the third target. By labeling the moving body in this way, the moving body is easily excluded from the third object, and the accuracy of the estimated vehicle speed is improved. Furthermore, in the vehicle body control device that controls the posture of the vehicle body 3, it becomes possible to perform processing based on the information on the label, for example, control of the vehicle body 3 such as collision avoidance, and the safety of the vehicle 2 is improved. Furthermore, an object that is stationary with respect to the ground is selected more easily and at a higher speed, and the vehicle speed estimation process becomes simpler.

  Further, the position of the stationary object on the map is recorded in the memory of the control device 10, and in step ST4, the control device 10 acquires the position of the stationary object on the map, and the second target is a stationary object. If the second target is a stationary object, it may be selected as the third target. In this way, by referring to the map and selecting the third target that is a stationary object from the second target, the estimation of the own vehicle speed is reflected from the stationary object located further forward with respect to the vehicle body 3. Accuracy can be improved because it can be done based on wave Doppler shift.

  In the above embodiment, an example in which electromagnetic waves having directivity are generated from the transmission device 5 has been described. However, the reception device 7 is provided with a plurality of reception devices 7, and the control device 10 performs measurement at the reception device 7 in step ST1. The intensity map may be constructed by detecting the direction of the reflected wave by measuring the phase difference of the reflected wave. Further, the transmission wave and the reception wave are not limited to electromagnetic waves, and for example, ultrasonic waves may be used.

  In the above embodiment, the control device 10 creates the intensity map and the frequency map at the same time. However, the control device 10 creates only the intensity map, selects the first target based on the intensity map, and then selects the first object. The frequency of the reflected wave corresponding to the mark may be detected. However, if the intensity map and the frequency map are created at the same time, it is not necessary to change the direction of the transmission device 5 after the intensity map is created, so that the own vehicle speed estimation process is further simplified.

1: Detection unit 3: vehicle body 10: Control unit L: reference line P, Q: area _S 1, _{S 2:} the first reference plane, the second reference plane [delta] ₁ ～Deruta _4: first angular width to the fourth angular width A to I: First target A to G: Second target A to E: Third target

Claims (6)

A detection device that is mounted on a vehicle body, radiates a transmission wave to the front side of the vehicle body, receives a reflected wave of the transmission wave, detects a target, and estimates the vehicle speed,
On a first reference plane including a reference line extending in front of the vehicle body from the detection device, a first target within a first angular width is detected symmetrically with respect to the reference line with the detection device as a starting point. ,
Of the first target, the Doppler shift of the reflected wave from the second target within the range of the second angular width symmetrically with respect to the reference line with the detection device as a starting point on the first reference plane The vehicle speed is estimated based on the detection apparatus.   The detection apparatus according to claim 1, wherein the first reference plane is parallel to the vehicle width direction.   The detection apparatus according to claim 1, wherein the first reference plane is parallel to the vertical direction. Based on the Doppler shift of the reflected wave from a plurality of the second target, to calculate the line-of-sight velocity of the second target with respect to the detection device,
For each of the second targets, a value obtained by dividing the line-of-sight velocity by the cosine of the angle formed by the straight line passing through the second target and the detection device and the straight line extending forward through the detection device. Speed and
Selecting the second target whose difference between the average value of the temporary speed and the temporary speed is a predetermined speed threshold value or less as a third target;
The detection apparatus according to any one of claims 1 to 3, wherein the host vehicle speed is estimated based on the temporary speed of the third target. When the difference between the temporary speed corresponding to each of the second targets and the estimated vehicle speed is greater than a predetermined moving body speed threshold, the second target moves relative to the ground. Label it as a body,
The detection apparatus according to claim 4, wherein the second target labeled as a moving object is not selected as the third target. The detection device further includes the reference line, and the second reference surface different from the first reference surface is symmetrical with respect to the reference line with the detection device as a starting point, and is within a range of a third angle width. Detect the target,
In the second reference plane, the own vehicle speed is estimated based on the Doppler shift of the reflected wave from the target within the range of the fourth angular width symmetrically with respect to the reference line, starting from the detection device. The detection device according to claim 1, wherein

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