WO2006123628A1

WO2006123628A1 - Radar and radar system

Info

Publication number: WO2006123628A1
Application number: PCT/JP2006/309688
Authority: WO
Inventors: Yuji Hirogari; Toru Ishii
Original assignee: Murata Manufacturing Co., Ltd.
Priority date: 2005-05-17
Filing date: 2006-05-16
Publication date: 2006-11-23

Abstract

A radar front end (30) acquires information about the orientation of a side road from a car navigation system (25). An operation processing section (18) determines the observation position of an object in a plane coordinate system that is on a plane parallel with the pavement and uses a parallel axis passing the beam transmitting/receiving point in its own car and parallel with the orientation of a side road and a perpendicular axis perpendicular to the orientation of a side road as coordinate axes. Furthermore, a decision is made whether the observation position is the position of a virtual image or not, and coordinate calculation is repeated using an approximate sidewall face as a symmetric axis if it is the position of a virtual image, thus calculating the position of an actual object.

Description

Specification

Radar and radar system

Technical field

The present invention relates to an in-vehicle radar using an electromagnetic wave and a radar system thereof.

More specifically, the present invention relates to a vehicle-mounted radar and a radar system for observing a target at a position with poor visibility.

Background art

[0002] When a car enters a bending point such as an intersection such as a lane or a crossroad or an L-shaped road 'curve road', it slows down, slows down, etc., and connects to the intersection or bending point. Of these, it is necessary to enter the road after confirming the safety of the road in the direction different from the self-propelled road (hereinafter referred to as the side road). However, in order to confirm the safety of unfamiliar sideways, it was dangerous because the condition of the sideway could not be confirmed unless the bonnet part was infiltrated to some extent.

[0003] Therefore, a technique for confirming the condition of a side road without almost intruding the bonnet portion is known.

In Patent Document 1, driving conditions such as road equipment, other cars and pedestrians are detected by a radar or the like attached to a traffic light, and traffic safety at intersections and bending points is improved by traffic light control and warning information.

Also, in Patent Document 2, a plurality of imaging devices are provided on the hood, bumper, etc. of the own vehicle, and the images are displayed on the monitor to improve the visibility of the driver, when entering an intersection or bending point, or at the time of parking, etc. In addition, the visibility in the vicinity of the vehicle is improved, and safety is enhanced.

[0004] However, with these conventional technologies, advanced road infrastructure is in place! /, The power that can confirm the side roads only in the alleys, and the power that can only obtain information in the vicinity of the vehicle body In other words, each had problems and led to the provision of sufficient safety.

[0005] By the way, there is a millimeter wave radar technique as a technique for measuring the position force away from the position and speed of a target such as another vehicle. The in-vehicle radar using the millimeter-wave radar technology can recognize a target at a distant location by determining a target with speed as another vehicle and determining a target without speed as road equipment. Here, FIG. 1 (A) shows a conceptual diagram of radar observation in a general on-vehicle radar. As shown in Fig. 1, when the own vehicle 1 performs radar observation of the target 2, the position of the target 2 is captured by the radar beam 4 by shaking the radar beam 4 left and right by a predetermined angle. Target 2 is observed at the position of (R, Θ s) from the directivity angle (Θ s) of this radar beam and the distance (R) to target 2 (hereinafter, the observed position is referred to as the observation position). ) O

Patent Document 1: Japanese Patent Laid-Open No. 11-110685

Patent Document 2: Japanese Patent Laid-Open No. 2000-238594

Disclosure of the invention

Problems to be solved by the invention

[0007] It is conceivable to use such a radar to grasp road conditions such as intersections and sideways. However, it is only in the case of intersections and crossways where the target status can be ascertained with sufficient visibility.

In the scene of FIG. 1 (B), the radar beam is irradiated in the direction of the directivity angle (0 s) from the radar beam transmission / reception point (O) of the vehicle 1. This radar beam is reflected by the reflection point (S) on the side wall 5A and is irradiated to the position of the target (hereinafter referred to as the target position) (P). This radar beam is diffusely reflected at the target position (P), and some of the reflected waves are also reflected at the target position (P) force through the reflection point (S) on the side wall 5A. Received. If the radar beam is reflected by the side wall 5A in this way, the observation position (R, Θ s) is not at the actual target position P, even though there is no target at the observation position (R, Θ s). If a target is present in Θ s), it will be detected. When such a target detection position (hereinafter referred to as virtual image position) Q that is different from the actual target position P is observed, the radar determines whether the observation position (R, Θ s) is an actual target or a virtual image. I couldn't judge. Therefore, in the case of intersections and sideways that have no prospective interest, it is impossible to grasp the state of the target, and it is impossible to grasp the correct target position and target speed.

[0009] Therefore, the present invention uses a radar to observe the virtual image position Q even if it is a target at a position P on the side road that is shielded outside the field of view by a shield or the like, and coordinates of the virtual image position Q. The purpose is to provide a technology to grasp the actual condition of the target based on the above.

[0010] And even if the vehicle is in the state before entering the intersection, Providing a radar that can grasp the situation of the side road without the need for infrastructure.

Means for solving the problem

In order to solve the above problems, the present invention comprises observation means for transmitting an electromagnetic wave beam and receiving a reflected wave from the target of the beam and measuring the observation position of the target. In the in-vehicle radar, the road information acquisition means for acquiring information on the direction of the side road that is connected to an intersection or a bending point and is relatively close to the own vehicle, and the own vehicle on a plane parallel to the road surface. A coordinate position extracting means for obtaining an observation position of the target in a plane coordinate system passing through the beam transmission / reception point and having a parallel axis parallel to the direction of the lateral path and a vertical axis perpendicular to the coordinate axis; Is provided.

As described above, in the present invention, the observation position is obtained by a plane coordinate system (hereinafter, this coordinate system is expressed as an XY coordinate system) including a parallel axis parallel to the lateral path and a vertical axis perpendicular to the horizontal path. In this plane coordinate system, even if the observation position is the virtual image position Q (Qx, Qy), the actual target position P (Px, Py) and the virtual image position Q (Qx, Qy) are the same in parallel. The coordinate position (X coordinate) on the axis is obtained. Therefore, the coordinate position (Ρχ) on the parallel axis of the actual target can be obtained regardless of whether the observation position is a virtual image position or an actual target position.

[0013] Here, the information on the direction of the side road is information on the laying direction of the side road on which the target travels, information on the side wall and the position of the building, information on the center axis of the road, etc. Any information can be used as long as it can estimate the direction of the reflection surface of the radar beam based on the information. By obtaining such information as force notification information such as car navigation systems and road infrastructures, radar observation results, etc., the target position can be determined regardless of whether the observation position is a virtual image position or an actual target position. The coordinate position on the parallel axis can be obtained.

[0014] Further, in order to solve the above-described problem, in the present invention, the road information acquisition unit acquires information on the position of the entrance from the intersection or the bending point to the side road, and A target lateral path distance detecting means for obtaining a distance from the coordinate position of the observation position on the parallel axis and the coordinate position on the parallel axis of the lateral path entrance to the lateral path entrance of the target is provided.

[0015] As described above, in the present invention, the information power about the entrance of the sideway The position of the sideway entrance (Tx, Ty ) Then, the distance from the coordinate position (Tx) on the parallel axis of the entrance of this side road and the coordinate position (Px) on the parallel axis of the target position to the side entrance of the target along the parallel axis. (L) can be obtained. Therefore, regardless of whether the observation position is a virtual image position or an actual target position, the observation position force can also determine the distance (L) to the side entrance.

[0016] Note that the information related to the entrance of the side road is information such as the position of the stop line at the connection position between the intersection and the side road. By obtaining this information, for example, from car navigation systems, radar observation results, road infrastructure, etc., the target from the target to the entrance to the sideway, regardless of whether the observation position is a virtual image position or an actual target position. Can be obtained.

[0017] Further, in order to solve the above-described problem, the present invention measures the speed of the target in the beam direction together with the observation position of the target by the observation means, and determines the speed of the target in the beam direction. Target motion detection means for determining the speed of the target in the parallel axis direction based on the beam directing direction and the direction of the lateral path is provided.

As described above, in the present invention, the velocity (V) in the parallel axis direction of the target is obtained from the velocity (V) in the beam direction of the target obtained by radar observation. Assuming that the direction of movement of the target is the same as the direction of the parallel axis, the speed (V) of the target in the direction of the parallel axis can be regarded as the speed of the actual target. Therefore, regardless of whether the observation position is a virtual image position or an actual target position, the actual target speed (V) can be estimated from the observed target beam velocity W).

[0019] Further, in order to solve the above-described problem, the present invention provides the motion detection unit, wherein the parallel movement of the target is performed based on the speed in the parallel axis direction of the target obtained a plurality of times at regular intervals. Find the axial acceleration.

As described above, in the present invention, the acceleration (ο) in the parallel axis direction of the target is obtained from the velocity (V) in the beam direction of the target obtained by radar observation. The traveling direction of the target is the parallel axis direction. Therefore, the acceleration (α) of the target can be estimated regardless of whether the observation position is a virtual image position or an actual target position.

[0021] Further, in order to solve the above-mentioned problem, the present invention provides an approach determination for determining whether or not the target is approaching the host vehicle from the speed of the target in the parallel axis direction. Means. As described above, according to the present invention, it is possible to determine whether or not a state force is approaching an intersection or the like regardless of whether the observation position is a virtual image position or an actual target position.

[0023] Further, in order to solve the above problems, the present invention provides a means for determining whether the target can be stopped at a predetermined distance to the entrance of the side road, and when determining that the target cannot be stopped, Means for issuing a warning or automatically decelerating the driver.

[0024] As described above, according to the present invention, it is possible to make traffic at intersections and inflection points where visibility is unnoticeable by a warning to the driver or an instruction to automatically decelerate. The movement of the target can be estimated by velocity (V) and acceleration (oc), and if the target is assumed to move forward by the distance (L) to the entrance of the side road and stop, it is necessary to do so. The velocity (V) and acceleration (ex) at the current position can be estimated, and whether or not the target can be stopped can be determined based on whether or not these are realistic values.

[0025] Further, in order to solve the above-mentioned problem, in the present invention, the road information acquisition unit acquires information on the position of the first side wall and the position of the second side wall of the side road, and If there is no observation position in a region between the first side wall and the second side wall in the coordinate system, virtual image determination means for determining the observation position as a virtual image position is provided.

In this way, in the present invention, it is determined whether or not the target is positioned on the side road from the position of the side wall provided on the side road and the observation position of the target. Then, if the observation position of the target is on the side road, it can be considered that the actual position of the target has been observed, and if the observation position of the target is not on the side road, the position of the virtual image of the target is determined. It can be considered as observed.

[0027] The information on the position of the first side wall and the position of the second side wall of the side road is, for example, the installation position of the side wall or the position of the building, and the direction of the side wall that reflects the radar beam is If it can be estimated.

[0028] Further, in order to solve the above-described problem, the present invention provides a method in which, when the observation position is determined to be a virtual image position by the virtual image determination unit, the observation position of the first or second side wall is set to the observation position. A new observation position is obtained by coordinate calculation using the side wall surface that is close to and reflects the beam as an axis of symmetry, and the new observation position falls within a region sandwiched between the first side wall and the second side wall. The coordinate operation is repeated until the area between the first side wall and the second side wall is Target position estimating means for estimating the observed position as the actual position of the target.

As described above, according to the present invention, the actual target position P (Px, Py) can be estimated from the virtual image position Q (Qx, Qy) of the target.

[0030] Further, in order to solve the above-described problem, in the present invention, the road information acquisition unit acquires information by measuring a lateral road.

[0031] Further, in order to solve the above problems, the present invention further includes the above-described radar and a car navigation system, and the road information acquisition means acquires information used in the car navigation system.

[0032] In order to solve the above problems, the present invention further includes the above-described radar and a communication device, and the road information acquisition means is used in a road facility provided at an intersection using the communication device. Get information.

The invention's effect

[0033] As described above, according to the present invention, a virtual image is observed even if it is a target on a side road that is shielded outside the field of view by a shielding object or the like, and an actual target is detected based on the virtual image. The state can be grasped. And even if the vehicle is in a state before entering the intersection or in a shallow state, it is possible to provide a radar that grasps the situation of the side road without requiring road infrastructure.

Brief Description of Drawings

[0034] FIG. 1 is a conceptual diagram for explaining observation of a target with a conventional radar.

FIG. 2 is a conceptual diagram illustrating a plane coordinate system used for target observation according to the present invention.

FIG. 3 is a conceptual diagram illustrating calculation of target coordinates according to the present invention.

FIG. 4 is a conceptual diagram illustrating calculation of a target velocity according to the present invention.

FIG. 5 is a block diagram of a radar according to an embodiment.

FIG. 6 is a processing flowchart of the DSP according to the embodiment.

Explanation of symbols

[0035] 1, 6—Own vehicle 2 Target 4 Radar beam 5, 7 Side wall 10—Millimeter wave circuit 11—VCO 12-LPF 13—AD converter 15—DSP

16—FFT unit 17—Observation position / velocity calculation unit 18 Arithmetic processing unit 21—Antenna 22 Scan unit 25—Rikiichi navigation system 26—A CC controller 27—brake control unit 28—engine control unit 29—display controller 30—radar front end

BEST MODE FOR CARRYING OUT THE INVENTION

Here, a method for grasping the state of the target when the target at the position where the radar force is also shielded is observed as a virtual image will be described.

The relationship between the virtual image position Q and the target position P in the plane coordinate system shown in Fig. 2 is explained. The plane coordinate system consists of a parallel axis parallel to the side wall 7A of the reflection point (S) and a vertical axis.

In this plane coordinate system, the beam transmission / reception point 0 (0, 0) from the vehicle 6 and the reflection point S (

When Sx, Sy), the relationship between the target position P (Px, Py) and the virtual image position Q (Qx, Qy) is expressed by the following equation.

Px = Qx

Py = Sy- (Qy-Sy) = 2XSy-Qy

Also, the crossing angle (Θ) between the side wall 7A and the radar beam shown in the figure is based on the radar directivity angle (Θ s) and the angle of the side wall relative to the head direction of the vehicle 6 (0 w) as follows: Represented by an expression

Θ = Θ w-Θ s

The coordinate transformation function of the virtual image position Q (Qx, Qy) from the polar coordinate system to the planar coordinate system is expressed by the following equation. Here, the observation distance (R) is the distance through the reflection point S from the transmission / reception point O of the radar beam to the target position P.

Qx = RXcos (Θ) = RXcos (Θ w- Θ s) (1)

Qy = RXsin (θ) = RXsin (Θ w- Θ s) (2)

Therefore, the coordinate transformation function of the target position P (Px, Py) from the polar coordinate system to the planar coordinate system is expressed by the following equation.

Px = Qx = RXcos (Θ) = RXcos (Θ w— Θ s) (3)

Py = 2XSy-Qy = 2XSy-RXsin (Θw-Θs) (4)

Here, the observation distance (R) and the directivity angle (Θ s) can be obtained as radar output, and the side wall angle (Θ w) and the position of the reflection point (Sx, Sy) are used to acquire information power such as car navigation. If you can This target position P (Px, Py) can be calculated.

[0038] The coordinate position (Px) on the parallel axis of the target position P and the coordinate position (Qx) on the parallel axis of the virtual image position Q show the same value. That is, in this plane coordinate system, the coordinate position on the vertical axis where the coordinate position on the parallel axis is equal differs between the virtual image position and the actual target position. Therefore, by finding the observation position in a plane coordinate system with the direction of the side road as the reference coordinate axis, whether the observation position is a virtual image position or an actual target position, it is on the parallel axis of the actual target. The coordinate position (Px) can be obtained.

[0039] In such a plane coordinate system, if information about the coordinate position (Tx) on the parallel axis of the entrance of the side road can be obtained by a car navigation system or the like, the side road distance from the actual target position to the entrance of the side road (L) can be estimated by the following equation.

L = Px-Tx = Qx-Tx = RX cos (Θ w-Θ s) — Τχ · · (5)

Here, the observation distance (R) and the directivity angle (Θ s) can be obtained as radar output, and the side wall angle (Θ w) and the coordinate position (Tx) on the parallel axis at the entrance to the side road are Assuming that it can be obtained as an output, the distance (L) to the target entrance of the target can be calculated.

As described above, a method for calculating the target position when the radar beam is reflected only once and the radar beam is reflected multiple times will be described. In the case of a straight road surrounded by two parallel side walls 7A and 7B as shown in Fig. 3 (A), the actual target position P (Px, Py) is expressed by the following formula. Here, the beam transmission / reception point 0 (0, 0) of the vehicle 6, the beam reflection point Sn (Sx (n), Sy (n)) on the side wall 7A, and the beam reflection point Sn + 1 (Sx (n + 1)) on the side wall 7B , Sy (n + 1)). In addition, the virtual image position Qn + 1 (Qx (n + 1), Qy (n + 1)) of the target position P with the side wall 7B as the reflecting surface, and the virtual image position Qn (Qx (Qx ( n), Qy (n)).

[0041] Px = Qx (n + l) = Qx (n)

Py = 2 X Sy (n + l) -Qy (n + l)

Qy (n + l) = 2 X Sy (n) -Qy (n)

Here, if the virtual image position Qn can be obtained as the radar output, and the reflection point position Sn + 1 and the reflection point position Sn can be obtained as the output of the car navigation system, the target position in this case The position P can be calculated.

[0042] It should be noted that the target position P can be calculated by repeating the same method even when the reflection of the radar beam is two or more times as shown here.

[0043] The target position calculation method described above is a method for calculating a target position when a radar beam is reflected multiple times on a road surrounded by two parallel side walls. The target position can be calculated even when the road is surrounded by side walls or even on a power road if the inclination can be detected by a car navigation system or the like. As shown in Fig. 3 (B), in the case of a side road surrounded by side walls 7A and 7B of different angles, first, Qn to Qn + in the coordinate system with the parallel axis parallel to side wall 7A at reflection point Sn as the reference coordinate axis Ask for one. Next, Qn + 1 is converted into a coordinate system in which the parallel axis parallel to the side wall 7B at the reflection point Sn + 1 is the reference coordinate axis. Next, the actual target position P is obtained from Qn + 1 in this coordinate system. In this way, Qn obtained from the radar output, the angle of the side wall relative to the head direction of the own vehicle 6 obtained from the information power of car navigation etc. (θ1) and (Θ2), reflection The target position P can be calculated from the point positions Sn and Sn + 1.

[0044] <Calculation of target velocity>

Next, a method for calculating the velocity (V) of the target in the parallel axis direction based on the measured velocity W of the target beam W), the beam directivity angle (Θ s), and the direction of the lateral path (Θ w). Will be explained. In the radar observation, the relative velocity W) in the beam direction is detected.

[0045] As shown in Fig. 4 (A), the relative velocity (Vr) in the parallel axis direction of the target is first estimated from the relative velocity (V) in the beam direction of the target. The relational expression between the relative velocity (Vr) in the parallel axis direction of the target and the relative velocity W) in the beam direction of the target is shown below.

Vr = Vr '/ cos (θ)

In addition, as shown in Fig. 4 (B), the speed (V) in the parallel axis direction of the actual target based on the absolute speed (Vs) of the traveling of the host vehicle 6 and the relative speed (Vr) of the target. Can be requested. First, the formula for calculating the absolute velocity (V ') in the beam direction of the target is shown below.

V '= Vr' -Vs X cos (Θ s)

The calculation formula for calculating the absolute velocity (V) in the parallel axis direction of the target from the absolute velocity (V ^) in the beam direction of the target is shown below. V = V '/ cos (θ) = (Vr' -Vs X cos (Θ s)) / cos (θ)

••• (6)

As described above, the radar force directivity angle (Θ s) and the relative velocity (V) in the beam direction are obtained, and the absolute speed (Vs) of the vehicle 6 is obtained from the vehicle speed sensor, etc. By acquiring the information force angle (Θ) of the car navigation system force, the relative speed (Vr) of the target in the parallel axis direction and the absolute speed (V) of the target in the parallel axis direction can be calculated.

[0046] Further, it is possible to calculate the change amount force acceleration (h) of the target in a predetermined time of the absolute velocity (V) in the parallel axis direction of the target. Assuming that the absolute velocity (V) in the parallel axis direction of the target changes from V (n) to V (n + 1) at time (T), the acceleration (α) of the target is expressed by the following equation: .

Thus, since the speed and acceleration of the target can be calculated, the movement of the target can be grasped.

When a virtual image is observed, the observation position is located deeper than the sideways (observed deeper than the buildings and side walls). For this reason, if the road shape can be obtained from a car navigation system, it can be easily determined whether the observation position is an actual target position or a virtual image position. That is, from the coordinates (Sx, Sy) of the reflection point S, the following formula is established when the observation position is a virtual image.

Qy> Sy-(8)

In this way, it can be determined that the observation position is a virtual image position.

[0048] If the right route and the left route are considered as the horizontal route, and if it is determined that the target is running backward on the route that should have moved away, it can be determined to be a virtual image. It is possible to determine that the observation position is a virtual image position even when

Qy-Qs> W (9)

V> 0

Here, as shown in FIG. 4, (W) is the width of the line on one side, and (Qs) is the coordinate position on the vertical axis of the side wall 7B of the horizontal path on the lower side of the figure. Thus, when the width (W) of the route on one side can be obtained from information from a car navigation system, a virtual image can be determined with higher accuracy.

[0049] <Target stop judgment> Next, a description will be given of a method for determining whether or not a target is moving at a speed at which the target can quickly stop when the target enters an intersection or inflection point.

Therefore, it is determined whether the target can be stopped at the stop position, and when it is determined that the target cannot be stopped at the stop position! /, A warning is issued and the safety of the host vehicle 6 can be improved. There are two methods for determining whether or not a target is stopped: a method in which the target acceleration is used and a method in which the target acceleration is not used.

First, a method for performing determination using the acceleration of a target will be described. The time (Ts) during which the vehicle stops can be calculated by the following equation based on the acceleration (a) and speed (V) of the target.

Ts = -V / a

When the acceleration (OC) is positive, the target does not stop, only when it is negative. Then, the distance traveled before the target stops (Ls) is expressed by the following equation.

Ls = VXTs + 0.5X a XTs ²

Compare the distance traveled before the target stops (Ls) and the distance from the target position described above to the entrance to the side road (L).

L> Ls --- (11)

If this equation (11) holds, it can be determined that the target can be stopped.

[0051] Next, a method of performing determination without using the acceleration of the target will be described.

The time required for the target to stop (Tc) based on the target detection speed V and the above-mentioned target position force distance (L) to the side entrance is expressed by the following equation.

Tc = {— V (V ² + 2X a XL) ^V2 } / a

Here, the acceleration (oc) of the target when the velocity V stops at time Tc and stops is expressed by the following equation.

a = V ² / (2XL) (12)

Therefore, when the acceleration (α) is not within the realizable range (for example, α <—0.IX G, where G is the gravitational acceleration), it can be determined that the target cannot be stopped.

Embodiment of this invention for detecting each state of a target using the method shown above The configuration of the radar according to the above will be described.

FIG. 5 is a block diagram showing a configuration of the entire system including an on-vehicle radar and various units connected to the radar. In FIG. 5, the radar front end 30 also constitutes forces such as a millimeter wave circuit 10, a DSP (Digital Signal Processor) 15, an antenna 21, and a scan unit 22. Various external devices can be connected to the radar front end 30. Here, a car navigation system 25, an ACC controller 26, and a display controller 29 are connected.

[0054] The scan unit 22 scans the direction of the beam of the antenna 21 over a predetermined range, for example, by mechanical reciprocation according to a control signal from the DSP 15.

Further, the millimeter wave circuit 10 modulates the oscillation frequency of VCOll with the modulation data set by the DSP 15 and outputs it to the antenna 21 via the circulator. Also, part of the VCOll oscillation signal is input to the mixer as a local oscillation signal via the force bra. The antenna 21 transmits a millimeter wave beam and receives a reflected signal from the transmission direction. Also, the received signal is input to the mixer via the circulator, and the received signal and the local oscillation signal are mixed by the mixer. From this mixed signal, frequency components other than the necessary frequency are removed by LPF12 to generate an intermediate frequency signal (IF signal). The IF signal is sampled by the AD converter 13 to generate a digital IF signal. This digital IF signal is then fed to DSP 15.

[0056] In the DSP 15, the digital IF signal force also detects the target. In addition, modulation data is given to the millimeter wave circuit 10 and a control signal for controlling the directivity direction of the antenna 21 is output to the scan unit 22 so that the radar beam transmitted from the antenna 21 is directed to a predetermined direction. Observe the detection range at.

[0057] The FFT unit 16 of the DSP 15 performs spectrum modulation of the digital IF signal in order to detect the target from the digital IF signal. Then, the observation position / velocity calculation unit 17 detects the presence of a target within the radar beam search range from the spectrum obtained by the FFT unit 16, and calculates the radar beam traveling distance (R) to the target. Find the relative velocity W) of the target in the beam direction.

[0058] In the calculation processing unit 18, the radar beam up to the target obtained by the observation position / velocity calculation unit 17 is displayed. The travel distance (R) of the system and the relative velocity W in the beam direction of the target are obtained. Further, the directivity direction (Θ s) of the radar beam is obtained from the control signal of the scan unit 22. Also, from the carna pigation system 25, obtain the information on the side road that your vehicle is traveling to. Then, various operations described later are performed by various means characterized by the present invention, and the target information obtained by the various operations is supplied to the ACC controller 26 and the display controller 29.

[0059] Based on information such as the position and speed of the target given from the DSP 15, the ACC controller 26 performs vehicle speed control for limiting the approach speed to an intersection or the like, for example, below a certain speed. Therefore, control data for avoiding a collision with a target such as a vehicle traveling on a side road is given to the brake control unit 27 and the engine control unit 28. The brake control unit 27 and the engine control unit 28 perform engine control and brake control based on the control data given from the ACC controller 26.

[0060] Also, the display information of the target information power intersection is controlled. Therefore, control data for display control of warning information is given to the display controller 29. Based on the control data, the display controller 29 displays various indications on warning lamps and displays.

Next, an embodiment of processing in the DSP 15 will be described with reference to FIG.

[0062] (S1) First, the spectrum obtained by the FFT unit 16 is spectrally modulated by the observation position / velocity calculation unit 17, and the target observation position (R, 0) and the target in the beam direction are Calculate the relative speed (V).

[0063] (S2) Next, the arithmetic processing unit 18 also obtains information about the car navigation isotropic force. When obtaining information from the car navigation system 25, obtain information on the map, the position of the vehicle, and the direction of the side wall, and calculate the position of the side wall in the plane coordinate system from the information on the map and the direction of the side wall. Then, calculate the position of the side wall surface, the vehicle position, and the radar beam pointing angular force reflection point.

[0064] In the same way, road information of road facility power provided at the intersection is obtained via a communication device. When obtaining the position, the position of the side wall surface in the plane coordinate system is calculated from the road information, the distance to the wall surface and the directivity angle are obtained by radar observation, and the position of the host vehicle is calculated. The position of the reflection point is also calculated based on the position, the vehicle position, and the pointing angular force of the radar beam.

[0065] Further, when road information is also acquired for the radar observation result force, a target that is continuous at a fixed position is extracted as a side wall surface by radar observation, and the position in the plane coordinate system is calculated. In addition, the position of the host vehicle is calculated from the distance to the wall surface and the directivity angle acquired by radar observation, and the position of the side wall surface and the host vehicle, and the directivity angle force reflection point of the radar beam are calculated.

(S3) Next, the approach of the side road is detected from the road information. Note that this approach to the side road is detected based on the road information and the vehicle position. In addition, the position of the side wall may be extracted by radar observation, and the approach detection may be performed by extracting features of intersections and inflection points (detection of side wall discontinuities, etc.).

Here, when the approach of the side road is not detected, the process is terminated.

[0067] (S4) In addition, when approaching a side road is detected, the observation position is determined by the above-mentioned equation (1) (2).

(R, Θ) is converted to the observation position Q (Qx, Qy) in the polar coordinate system plane coordinate system.

[0068] (S5) (S6) (S7) Next, the observed positional force in the plane coordinate system The lateral path distance (L) is calculated by the above-described equation (5). In addition, the target velocity (V) is calculated by the above equation (6). In addition, the target acceleration (ex) is calculated by the above equation (7).

[0069] (S8) Next, according to the above-described equations (8), (9), and (10), the road shape force is determined whether the observation position Q (Qx, Qy) is the actual target position force virtual image position.

[0070] (S9) In the case of a virtual image, the actual target position P (Px, Py) is calculated according to the above equations (3) and (4).

[0071] (S 10) When the actual target position P (Px, Py) is obtained, the approach of the target is determined by the above-described equations (11) and (12). Determine whether the target can be safely stopped. If the target can be safely stopped, the process ends.

(Sll) (S 12) If the target cannot be stopped safely, a control command to the ACC controller 26 is generated and display data to the display controller 29 is generated. Then, the ACC controller 26 uses the brake control unit 27 based on the control command. To control the brakes and the engine control unit 28 to control the engine torque. The display controller 29 notifies the driver of warning information based on the display data.

[0073] As described above, in the radar according to the present embodiment, a virtual image is observed even if it is a target on the side of a road that is shielded outside the field of view by a shielding object, and an actual object is based on the virtual image. You can grasp the condition of the mark. By using this radar, even if the vehicle is in a state before entering the intersection or in a shallow state, it is possible to grasp the situation of the side road without requiring road infrastructure and notify the driver of the intersection. You can help with safer traffic.

It should be noted that the present invention can be similarly applied to a monopulse radar other than the above-described radar using spectral modulation.

Claims

The scope of the claims

[1] In an on-vehicle radar equipped with observation means for transmitting an electromagnetic wave beam and receiving a reflected wave from the target of the beam and measuring the observation position of the target,

Road information acquisition means for acquiring information about the direction of a side road that is connected to an intersection or inflection point and is relatively close to the vehicle;

Observation of the target in a plane coordinate system on a plane parallel to the road surface and passing through the beam transmission / reception point of the vehicle and having a parallel axis parallel to the direction of the lateral road and a vertical axis perpendicular to the coordinate axis. A radar comprising coordinate position extraction means for obtaining a position.

[2] The road information acquisition means acquires information on the position of the entrance from the intersection or the bending point to the side road,

Target trajectory distance for determining the distance from the coordinate position on the parallel axis of the observation position of the target and the coordinate position on the horizontal axis of the entrance of the traverse to the entrance of the trajectory of the target The radar according to claim 1, further comprising detection means.

[3] The observation means measures the velocity in the beam direction of the target together with the observation position of the target,

The target motion detection means for obtaining the speed of the target in the parallel axis direction based on the speed of the target in the beam direction, the direction of the beam, and the direction of the lateral path. Item 3. The radar according to item 2.

4. The radar according to claim 3, wherein the motion detection means obtains the acceleration of the target in the parallel axis direction based on the speed of the target in the parallel axis direction obtained a plurality of times at regular intervals.

[5] The radar according to claim 3 or 4, further comprising an approach determining unit that determines whether or not the target is approaching the host vehicle from the speed of the target in the parallel axis direction.

[6] Means for determining whether the target can be stopped at a predetermined distance to the entrance of the side road, and a command to issue a warning or automatically decelerate to the driver when it is determined that the target cannot be stopped The radar according to any one of claims 1 to 5, further comprising: means for emitting

[7] In the road information acquisition means, the position of the first side wall and the position of the second side wall of the side road Information about

If there is no observation position in a region between the first side wall and the second side wall in the plane coordinate system, virtual image determination means for determining the observation position as a virtual image position is provided. The radar according to any one of claims 1 to 6.

[8] When the observation position is determined to be a virtual image position by the virtual image determination means, the side wall surface that is close to the observation position and reflects the beam on the first or second side wall is symmetrical. A new observation position is obtained by coordinate calculation as

The coordinate calculation is repeated until the new observation position falls within the area sandwiched between the first side wall and the second side wall, and the new observation position falls within the area sandwiched between the first side wall and the second side wall. The radar according to claim 7, further comprising target position estimating means for estimating an observation position as an actual position of the target.

[9] The road information acquisition means according to any one of claims 1 to 8, wherein the road information acquisition means acquires information by measuring a lateral road! The radar according to item 1.

[10] A radar system further comprising the radar according to any one of claims 1 to 8 and the car navigation system, wherein the road information acquisition means acquires information used in the car navigation system.

[11] The radar according to any one of claims 1 to 8, further comprising a communication device, wherein the road information acquisition means is information used in road equipment provided at an intersection using the communication device. To get radar system.