CN106428001B - A kind of lane change method for early warning and system for vehicle - Google Patents

Abstract

The invention discloses a kind of lane change method for early warning and system for vehicle, are related to technical field of vehicle safety.The lane change method for early warning for vehicle is used to warn the lane change behavior that is potential or being carrying out of the driver of the vehicle, including：The object of the vehicle periphery is detected, and determines its relative position and relative velocity relative to the vehicle；Determine if to enter the default prewarning area of the vehicle according to the relative position of the object；Determine that the object enters the approach axis of the default prewarning area；According to the approach axis of the object, and if to carry out the so described vehicle of lane change according to the relative velocity and/or the relative position determination vehicle and whether have risk of collision with the object；It alarms in the case where determining has the risk of collision to the driver.The present invention also provides corresponding systems.The present invention can effectively promote the safety of vehicle lane change.

Description

A lane change warning method and system for vehicles

technical field

The invention relates to the technical field of vehicle safety, in particular to a lane change warning method and system for vehicles.

Background technique

With the increase of the number of vehicles, the probability of traffic accidents is also increasing, especially in the process of vehicle lane change, due to the existence of blind spots in the field of vision, it is difficult for the driver to accurately judge whether there is a vehicle in the blind spot, which makes the lane change process very dangerous.

At present, in order to ensure the safety of lane changing, vehicle manufacturers install ultrasonic radars on the left and right sides of the rear bumper of the vehicle to detect the blind spot area behind the vehicle side, which reduces the risk of vehicle lane changing to a certain extent.

However, the above-mentioned ultrasonic radar can only detect the blind spots of 3×3 meters on the left and right sides of the vehicle, and cannot detect the blind spots in other farther areas, and when a vehicle approaching the own car approaches quickly, the driver will be in danger if he changes lanes , the radar cannot effectively detect and warn the driver.

Contents of the invention

An object of the present invention is to provide a lane change warning method for vehicles, through which, not only can the detection range of the blind spot area behind the vehicle be expanded, but also vehicles that are rapidly approaching the vehicle can be detected and the driver can be given an effective warning. warning effect.

A further object of the present invention is to provide a lane change warning system for vehicles, which can not only expand the detection range of the blind spot area on the side and rear of the vehicle, but also detect vehicles approaching the vehicle quickly and give the driver an effective warning .

In particular, the present invention provides a lane change warning method for a vehicle, which is used to warn the driver of the vehicle of a potential or ongoing lane change behavior, including:

detecting objects around the vehicle, and determining the relative position and relative velocity of the objects relative to the vehicle;

According to the relative position of the target, it is determined whether the target has entered the preset early warning area of the vehicle; the preset early warning area includes the blind area of the rearview mirror of the vehicle and the blind area from the rearview mirror an elongated area extending backwards, the preset warning area extending backwards from the rear of the vehicle for a distance of at least 40 meters;

Determining the entry direction of the target object entering the rearview mirror blind area and/or the elongated area in the preset early warning area;

determining whether there is a risk of collision between the vehicle and the object if the vehicle is to perform a lane change according to the direction of entry of the object and according to the relative speed and/or the relative position; and

In the event that the risk of collision is determined, the driver is warned.

Further, if the target object enters the elongated area from the rear or side, the distance between the vehicle and the target object is calculated according to the relative speed and the relative position if the vehicle is about to change lanes. Collision time, if the collision time is less than a preset collision time, it is determined that there is the collision risk;

In the case that the target enters the blind area of the rearview mirror from the rear or side, it is judged whether the reflection cross-sectional area of the target exceeds a preset value in the blind area of the rearview mirror, and if so, Then it is determined that there is the collision risk, otherwise it is determined that there is no collision risk.

Further, if the target object enters the elongated area from the rear or side, the distance between the vehicle and the target object is calculated according to the relative speed and the relative position if the vehicle is about to change lanes. The collision time is calculated, and the residence time of the target object in the extended area is calculated. If the collision time is less than a preset collision time and the residence time exceeds a preset residence time, it is determined that there is a collision risk.

Further, when the target object enters the preset early warning area from the front, it is determined whether the relative speed is greater than or equal to a preset relative speed.

Further, if the relative speed is greater than or equal to the preset relative speed, it is determined that there is no risk of collision.

Further, when the relative speed is less than the preset relative speed, if the target enters the blind area of the rearview mirror from the front , judging whether the reflection cross-sectional area of the target exceeds a preset value in the blind area of the rearview mirror, if so, determining that there is the collision risk, otherwise determining that there is no collision risk;

If the target enters the elongated area from the front, calculate the collision time between the vehicle and the target if the vehicle is to change lanes according to the relative speed and the relative position, if the collision time is less than a preset collision time, then it is determined that there is the collision risk;

Optionally, if the target enters the elongated area from the front, calculate the collision time between the vehicle and the target if the vehicle is about to change lanes according to the relative speed and the relative position, and calculate The residence time of the target object in the extended area, if the collision time is less than a preset collision time and the residence time exceeds a preset residence time, it is determined that there is the collision risk.

Further, it also includes judging whether the driver has an intention to change lanes;

Wherein, the alarm includes a first-level alarm and a second-level alarm, and the first-level alarm is given to the driver when there is the risk of collision but there is no intention to change lanes. When there is a risk and there is an intention to change lanes, the driver is given the second level of warning.

In particular, the present invention also provides a lane change warning system for a vehicle, which is arranged at the vehicle and used to warn the driver of the vehicle of a potential or ongoing lane change behavior, including:

an object detection device, configured to detect an object around the vehicle, and determine the relative position and relative velocity of the object relative to the vehicle;

The early warning area entry determination device is used to determine whether the target object enters the preset early warning area of the vehicle and determine the direction of entry according to the relative position of the target object; wherein, the preset early warning area includes the The blind area of the rearview mirror of the vehicle and the elongated area extending backward from the blind area of the rearview mirror, the preset warning area extends backward from the rear of the vehicle for a distance of at least 40 meters; the direction of entry includes the target The direction in which objects enter the blind area of the rearview mirror and/or the elongated area in the preset early warning area;

a collision risk determination device, configured to determine, according to the entering direction of the target object and according to the relative speed and/or the relative position, whether the vehicle and the target object there is a risk of collision; and

An alarm device is configured to issue an alarm to the driver when it is determined that there is the collision risk.

Further, the target detection device includes a millimeter-wave radar.

Further, it also includes a lane-changing intention judging device, which is used to judge whether the driver has a lane-changing intention;

Wherein, the alarm device includes a first-level alarm unit and a second-level alarm unit, and the first-level alarm unit gives an alarm to the driver when there is the collision risk but no lane change intention , when there is the risk of collision and there is the intention to change lanes, the first-level and the second-level alarm units simultaneously issue an alarm to the driver;

Optionally, the first level warning unit includes a warning light arranged adjacent to an exterior rearview mirror on each of the two sides of the vehicle.

The lane change warning method and system for vehicles of the present invention not only expands the detection range of the blind spot area behind the vehicle by detecting the target information within a distance of at least 40 meters behind the vehicle, but also can detect vehicles that are rapidly approaching the own vehicle. Detect and give the driver an effective warning in time, thus greatly improving the safety of vehicles changing lanes.

Those skilled in the art will be more aware of the above and other objects, advantages and features of the present invention according to the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of illustration and not limitation with reference to the accompanying drawings. The same reference numerals in the drawings designate the same or similar parts or parts. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the attached picture:

Fig. 1 is a working flow diagram of a lane change warning method for a vehicle according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of a vehicle detection range according to an embodiment of the present invention;

Fig. 3 is a specific work flow chart of determining the direction of entry of objects and judging the risk of collision according to an embodiment of the present invention;

Fig. 4 is a schematic diagram of a typical working scene of a lane change warning method for a vehicle according to an embodiment of the present invention;

Fig. 5 is a functional block diagram of a lane change warning system for vehicles according to an embodiment of the present invention.

Detailed ways

Fig. 1 is a working flow diagram of a lane change warning method for a vehicle according to an embodiment of the present invention, and Fig. 2 is a schematic diagram of a vehicle detection range according to an embodiment of the present invention. Referring to FIG. 1 , and also referring to FIG. 2 , this embodiment will be described mainly based on FIG. 1 . The lane change warning method for a vehicle is used to warn the driver of the vehicle of a potential or ongoing lane change behavior, which may generally include the following steps:

S100, detecting a target object around the vehicle, and determining the relative position and relative speed of the target object relative to the vehicle;

S200. Determine whether the target object enters the preset early warning area 100 of the vehicle according to the relative position of the target object. If it enters the preset early warning area 100, proceed to S300. If the early warning area is set to 100, then enter S501, indicating that no alarm is required. The preset early warning area 100 includes a rearview mirror blind area of the vehicle and an elongated area extending backward from the rearview mirror blind area, and the preset early warning area 100 extends backward at least 40 meters from the rear of the vehicle Here, 40 meters is not fixed, it can be 20 meters, 30 meters or even 70 meters, subject to being able to detect the target and warn the driver in time to achieve a safe lane change.

S300, determining the entry direction of the target object entering the blind area of the rearview mirror and/or the elongated area in the preset early warning area 100;

S400. Determine according to the entering direction of the target object and according to the relative speed and/or the relative position whether there is a risk of collision between the vehicle and the target object if the vehicle is about to change lanes, When it is determined that there is the collision risk, go to S500, otherwise go to S501; and

S500. Alarming the driver when it is determined that there is the collision risk.

This method not only expands the detection range of the blind spot area on the side and rear of the vehicle by detecting the target information within a distance of at least 40 meters behind the vehicle, but also can detect the vehicle that is approaching the vehicle quickly and give the driver an effective warning in time, thus Greatly improved the safety of vehicles changing lanes.

Fig. 3 is a specific work flow chart of determining the direction of entry of the target and judging the risk of collision according to an embodiment of the present invention. As shown in Fig. 3, in S300, the step of determining the direction of entry of the target includes Step S301 of entering the preset warning area from the side and step S302 of entering the preset warning area from the front. The step S301 of entering the preset early warning area from the rear or side includes the step S303 of entering the elongated area from the rear or side and the step S304 of entering the blind area of the rearview mirror from the rear or side.

In the case that the target object enters the elongated area from the rear or side, step S402 calculates the collision between the vehicle and the target object if the vehicle is about to change lanes according to the relative speed and the relative position time, if the collision time is less than a preset collision time, go to step S404 to determine that there is a collision risk, and if it is greater than or equal to the preset collision time, go to step S405 to determine that there is no collision risk. Here, the preset collision time may be 3.5s.

In the case that the target enters the blind area of the rearview mirror from the rear or side, step S403 judges whether the reflection cross-sectional area of the target exceeds a preset value in the blind area of the rearview mirror, if If yes, proceed to step S404 to determine that there is the collision risk, otherwise proceed to step S405 to determine that there is no such collision risk. Here, the preset value can be 50%, preferably, the preset value can be 70%, and the reflection cross-sectional area (RCS) is the cross-sectional area swept by the radar beam, which reflects the reflected energy of the radar beam .

In another embodiment of the present invention, in the case that the target enters the elongated area from the rear or side, it is calculated according to the relative speed and the relative position if the vehicle is going to change lanes, then the The collision time with the target object, and step S402 calculates the residence time of the target object in the extended area, if the collision time is less than a preset collision time and the residence time exceeds a preset residence time, The collision risk is then determined. Here, the preset collision time may be 3.5s, and the preset dwell time may be 300ms. In this case, the reason for judging the residence time of the target object in the extended area may be to prevent the target object from suddenly decelerating, accelerating or changing lanes to leave the warning area and erroneously alerting the driver to the danger of changing lanes.

Further, in the case that the target object enters the preset early warning area from the front, step S401 determines whether the relative speed is greater than or equal to a preset relative speed. If the relative speed is greater than or equal to the preset relative speed, it is determined that there is no collision risk. If the relative speed is less than the preset relative speed, proceed to step S305 where the target enters the elongated area from the front and step S306 where the target enters the blind area of the rearview mirror from the front.

When the object enters the elongated area from the front, proceed to step S402 to judge the collision risk; when the object enters the blind area of the rearview mirror from the front, proceed to step S403 to judge the collision risk.

In one embodiment of the present invention, if the target enters the elongated area from the front, the collision between the vehicle and the target is calculated according to the relative speed and the relative position if the vehicle is about to change lanes time, and calculate the residence time of the target object in the extended area, if the collision time is less than a preset collision time and the residence time exceeds a preset residence time, it is determined that there is a collision risk.

In addition, in S400, after judging that the vehicle has a collision risk, it will be further judged whether the driver has the intention to change lanes, and thus divide the alarm level into two levels. Specifically, in S500, it is judged that the vehicle If there is the risk of collision but there is no intention to change lanes, a first-level warning is issued to the driver, and when there is a risk of collision and there is the intention to change lanes, a second-level warning is issued to the driver Call the police.

More specifically, judging whether the driver has the intention to change lanes can be performed according to whether the turn signal of the vehicle is turned on. If the turn signal is turned on, it is determined that the driver has the intention to change lanes, otherwise, there is no intention to change lanes. At the same time, the first-level alarm can be that the warning light at the inner triangle plate of the door controlled by the vehicle door module is always on or the warning light arranged at the exterior rearview mirror is always on to warn the driver of the danger of changing lanes. The alarm can be to start the alarm light at the inner triangle plate of the corresponding side of the vehicle controlled by the vehicle door module or the alarm light arranged at the exterior rearview mirror to strengthen the warning function, and at the same time start the instrument buzzer controlled by the instrument control unit. The buzzer gives an audible alarm to warn the driver of the danger of changing lanes. Here, the strobe frequency of the warning light can be 4HZ.

In addition, in an embodiment of the present invention, in order to make the judgment of the lane change intention more accurate, the following method can also be used, as shown in Table 1, Table 1 is the analysis table of the driver's lane change intention, which is calculated by steering wheel angle, The turn signal information, yaw rate and the position of the ego vehicle relative to the lane line are variables, and their respective weights are 0.3, 0.4, 0.1 and 0.2. The weighted average method is used to calculate the driver's lane change intention. When the weighted average result If it is greater than 0.6, it is judged that there is an intention to change lanes, otherwise it is judged that there is no intention to change lanes, as shown in the first row of Table 1, when the steering wheel angle is greater than the calibrated value, the turn signal is not turned on, the yaw rate is less than the calibrated value, and the ego vehicle is facing the lane When the line position is less than 0.7m, the system judges that the driver has no intention to change lanes (the comprehensive judgment result in the table shows “×”). In other cases, it can be judged sequentially. Here, the calibration value of the steering wheel angle can be 90°/ s, the yaw rate can be 0.25rad/s (can be calibrated).

Judging the driver's intention to change lanes based on the above method is more accurate than judging only based on the turn signal information, so the follow-up work will be more effective and smooth, which greatly avoids the occurrence of such situations as the wrong turn signal. And lead to the occurrence of the implementation of the second level alarm situation.

Table 1 Analysis table of driver's lane change intention

Of course, in other embodiments, in order to make the judgment of the driver's lane-changing intention more accurate, it is also possible to add variables such as vehicle speed information and redistribute weights on the basis of Table 1, and re-draw the weighted average result at the same time, It is also possible to reset several new variables and assign weights to draw up weighted average results. In a word, as long as the solution can improve the accuracy of the driver's determination result and can be realized by those skilled in the art, it is within the scope of protection of this embodiment.

Figure 4 shows a schematic diagram of a typical working scene of the lane change warning method for vehicles. There is a target vehicle 3, and the surrounding ground is also divided into different areas by letters A, B, C, D, E, F, G, H, O, J. In these areas, if a vehicle enters the In the area indicated by FGBC, an alarm will be given. If a vehicle enters the area indicated by ADGH, an alarm may be issued according to the actual situation. If a vehicle enters the area indicated by FCG, and the collision time between the two vehicles is less than 3.5s, it will alarm. Here, the time to collision between the two vehicles (Time to collision, abbreviated TTC) can be calculated using the following equation:

Where a _Rel , v _Rel , d _Rel , and t represent relative acceleration, relative speed, relative distance, and the time required for the two vehicles to collide, respectively, and the relative acceleration, relative speed, and relative distance can be obtained through the millimeter-wave radar detected.

In this working condition of this embodiment, the target vehicle 3 is completely behind the O line, partly on the left side of the F line, completely on the right side of the G line, and partly between the E line and the J line. In this case, It can be determined that the target vehicle 3 completely poses a threat to the lane change of the own vehicle 1, and due to the uncertainty of the driving of the target vehicle 3, both sides of the vehicle need to call the police at the same time, so that the safety of the lane change of the own vehicle 1 can be guaranteed .

Fig. 5 has provided the functional block diagram of the lane change warning system for vehicle, as shown in Fig. 5, a kind of lane change warning system for vehicle is arranged at described vehicle place and is used for the driver's potential of described vehicle The lane changing behavior that is currently or is being executed is alerted, which may generally include a target object detection device 10 , a warning area entry determination device 20 , a collision risk determination device 30 and an alarm device 40 . The object detection device 10 is used for detecting objects around the vehicle, and determining the relative position and speed of the objects relative to the vehicle. The early warning area entry determination device 20 is used to determine whether the target object enters the preset early warning area of the vehicle and determine the direction of entry according to the relative position of the target object; wherein, the preset early warning area includes The blind area of the rearview mirror of the vehicle and the elongated area extending backward from the blind area of the rearview mirror, the preset early warning area extends backward from the rear of the vehicle for a distance of at least 40 meters; the direction of entry includes the The direction in which the target object enters the blind area of the rearview mirror and/or the elongated area in the preset early warning area. The collision risk determining device 30 is used to determine, according to the entering direction of the target object, and according to the relative speed and/or the relative position, if the vehicle is going to change lanes, the distance between the vehicle and the target object whether there is a risk of collision. The warning device 40 is used for warning the driver when the risk of collision is determined.

The lane change warning system for vehicles not only expands the detection range of the blind spot area behind the vehicle by detecting the target information within a distance of at least 40 meters behind the vehicle, but also can detect vehicles that are rapidly approaching the vehicle and give timely warnings. The driver has an effective warning function, thus greatly improving the safety of the vehicle changing lanes.

Specifically, the object detection device 10 may include a millimeter-wave radar 101 (shown in FIG. 2 ), located at the side and rear of the vehicle. Here, the millimeter-wave radar 101 may be a 77GHz millimeter-wave radar. Among them, the technical principle of the millimeter-wave radar to collect vehicle-related information is: by transmitting continuous frequency-variable electromagnetic wave signals and receiving the electromagnetic wave energy reflected by the target vehicle, the relative distance and relative speed are calculated; through the frequency modulation Doppler radar working mode, it can be effectively Position the angle, speed and distance of the target vehicle, specifically, the Doppler frequency shift f _d =2V _r /λ=(2V cosθ)/λ, where V _r =V cosθ is the relative speed of the target relative to the radar, and λ is Radar wavelength, V is the absolute speed of the target, θ is the angle between the target direction and the radar beam, and the corresponding target angle can be obtained by recording the launch beam angle and reflection angle in polar coordinates.

Further, in an embodiment of the present invention, the lane change warning system for vehicles further includes a lane change intention judging device, which is used to judge whether the driver has a lane change intention, for example, it may be the aforementioned device for judging The electronic control device for whether the turn signal is turned on or not. At the same time, the alarm device includes a first-level alarm unit and a second-level alarm unit, and the first-level alarm unit gives an alarm to the driver when there is the risk of collision but there is no intention to change lanes , when there is the risk of collision and there is the intention to change lanes, the first-level and the second-level alarm units simultaneously issue an alarm to the driver. Here, the first-level alarm unit may include a warning light arranged adjacent to the exterior rearview mirror on each side of the vehicle or a warning light at the inner triangle plate of the door, and the second-level alarm unit may be Instrument buzzer controlled by instrument control unit.

In addition, in an embodiment of the present invention, the lane change warning system for vehicles may further include a control switch for activating and deactivating the lane change warning system, and the control switch may be set at the dashboard of the vehicle, And the switch signal is transmitted by the instrument control unit. The control switch can also be set at the multimedia LCD screen of the vehicle, and the switch signal is transmitted by the multimedia interactive system control unit. In addition, the control switch can also be controlled by the body control unit to realize one-key Opening and closing, of course, other opening and closing methods are also possible, as long as the system can be opened/closed according to the requirements.

Further, in order to better warn the driver of the danger of changing lanes and make the driver understand the reason for the vehicle alarm, the lane changing warning system for the vehicle may also include a man-machine interface for displaying information about the danger of lane changing, Here, the human-computer interaction interface may be a display screen of the driving computer, and the collision risk determination device 30 can easily display the dangerous information of lane changing on the display screen by transmitting the dangerous signal of lane changing to the driving computer.

In addition, the millimeter wave radar 101 may include a master radar and a slave radar, the master radar and the slave radar may be connected through a private controller area network, and the master radar and the vehicle controller area network may be connected through a public controller area network The warning area entry determining device 20 and the collision risk determining device 30 may be at the main radar.

In addition, in an embodiment of the present invention, in order to ensure the normal operation of the lane change warning system, a self-inspection unit is usually included, which is used to detect whether the lane change warning system is faulty before it is activated.

So far, those skilled in the art should appreciate that although the exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, the content disclosed in the present invention can still be used directly. Numerous other variations or modifications consistent with the principles of the invention are identified or derived. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (11)

1. A lane change early warning method for a vehicle, used to warn the driver of the vehicle of a potential or ongoing lane change behavior, comprising: detecting objects around the vehicle, and determining the relative position and relative velocity of the objects relative to the vehicle; According to the relative position of the target, it is determined whether the target has entered the preset early warning area of the vehicle; the preset early warning area includes the blind area of the rearview mirror of the vehicle and the blind area from the rearview mirror an elongated area extending backwards, the preset warning area extending backwards from the rear of the vehicle for a distance of at least 40 meters; Determining the entry direction of the target object entering the rearview mirror blind area and/or the elongated area in the preset early warning area; determining whether there is a risk of collision between the vehicle and the object if the vehicle is to perform a lane change according to the direction of entry of the object and according to the relative speed and/or the relative position; and alerting the driver if the risk of collision is determined to be present; Wherein, in the case that the target enters the elongated area from the rear or side, the collision between the vehicle and the target is calculated according to the relative speed and the relative position if the vehicle is about to change lanes time, if the collision time is less than a preset collision time, it is determined that there is the collision risk; In the case that the target enters the blind area of the rearview mirror from the rear or side, it is judged whether the reflection cross-sectional area of the target exceeds a preset value in the blind area of the rearview mirror, and if so, Then it is determined that there is the collision risk, otherwise it is determined that there is no collision risk. 2. The method according to claim 1, characterized in that, in the case that the target object enters the elongated area from the rear or side, it is calculated according to the relative speed and the relative position if the vehicle is going to If the collision time between the vehicle and the target is changed, and the residence time of the target in the extended area is calculated, if the collision time is less than a preset collision time and the residence time exceeds a preset If the dwell time is set, the collision risk is determined. 3. The method according to claim 1 or 2, characterized in that, when the target object enters the preset early warning area from the front, it is determined whether the relative speed is greater than or equal to a preset relative speed . 4. The method according to claim 3, wherein if the relative speed is greater than or equal to the preset relative speed, it is determined that there is no risk of collision. 5. The method according to claim 4, wherein when the relative speed is less than the preset relative speed, if the target enters the blind area of the rearview mirror from the front, it is judged that the Whether the reflection cross-sectional area of the target exceeds a preset value in the blind area of the rearview mirror, if so, determine that there is the risk of collision, otherwise determine that there is no risk of collision; If the target enters the elongated area from the front, calculate the collision time between the vehicle and the target if the vehicle is to change lanes according to the relative speed and the relative position, if the collision time is less than A preset collision time, then it is determined that there is the collision risk. 6 . The method according to claim 5 , wherein if the target enters the elongated area from the front, the vehicle is calculated according to the relative speed and the relative position if the vehicle is about to change lanes. The collision time with the target object, and calculate the residence time of the target object in the extended area, if the collision time is less than a preset collision time and the residence time exceeds a preset residence time, then determine There is a risk of said collision. 7. The method according to claim 1, further comprising judging whether the driver has an intention to change lanes; Wherein, the alarm includes a first-level alarm and a second-level alarm, and the first-level alarm is given to the driver when there is the risk of collision but there is no intention to change lanes. When there is a risk and there is an intention to change lanes, the driver is given the second level of warning. 8. A lane change warning system for a vehicle, which is arranged at the vehicle and is used to warn the driver of the vehicle of a potential or ongoing lane change behavior, comprising: an object detection device, configured to detect an object around the vehicle, and determine the relative position and relative velocity of the object relative to the vehicle; The early warning area entry determination device is used to determine whether the target object enters the preset early warning area of the vehicle and determine the direction of entry according to the relative position of the target object; wherein, the preset early warning area includes the The blind area of the rearview mirror of the vehicle and the elongated area extending backward from the blind area of the rearview mirror, the preset warning area extends backward from the rear of the vehicle for a distance of at least 40 meters; the direction of entry includes the target The direction in which objects enter the blind area of the rearview mirror and/or the elongated area in the preset early warning area; a collision risk determination device, configured to determine, according to the entering direction of the target object and according to the relative speed and/or the relative position, whether the vehicle and the target object There will be a risk of collision; wherein, in the case that the target enters the elongated area from the rear or side, according to the relative speed and the relative position, if the vehicle is about to change lanes, then the The collision time of the target object, if the collision time is less than a preset collision time, it is determined that there is the collision risk; in the case that the target object enters the blind area of the rearview mirror from the rear or side, it is judged Whether the reflection cross-sectional area of the target exceeds a preset value in the blind area of the rearview mirror, if so, determine that there is the risk of collision, otherwise determine that there is no risk of collision; and An alarm device is configured to issue an alarm to the driver when it is determined that there is the collision risk. 9. The system according to claim 8, wherein the object detection device comprises a millimeter wave radar. 10. The system according to claim 8, further comprising a lane-changing intention judging device for judging whether the driver has a lane-changing intention; Wherein, the alarm device includes a first-level alarm unit and a second-level alarm unit, and the first-level alarm unit gives an alarm to the driver when there is the collision risk but no lane change intention , when there is the risk of collision and there is the intention to change lanes, the first-level and the second-level alarm units simultaneously issue an alarm to the driver. 11. The system of claim 10, wherein the first level warning unit includes a warning light disposed adjacent an exterior rearview mirror on each of the sides of the vehicle.