CN103578294B - A kind of bend based on Dedicated Short Range Communications, works in coordination with intelligent collision warning method - Google Patents

Abstract

The invention discloses a collaborative collision avoidance early warning method for curves based on dedicated short-range communication. The specific steps are: to obtain the real-time position information of the own vehicle, combined with an electronic map, to judge whether the vehicle enters the curve area; The dedicated short-range communication device broadcasts the driving information of the own vehicle to the surroundings and inquires whether there is an oncoming vehicle; if there is, it obtains the driving information and location information of the oncoming vehicle and combines the driving information and location information of the own vehicle to predict the minimum vehicle crossing time. The lateral distance and the time required to reach the intersection are compared with the set threshold to judge and perform graded collision avoidance warning. The invention has the advantages of being able to predict the minimum lateral distance of the vehicle at the intersection and the time required to reach the intersection, and realize the interaction between the vehicle state and the early warning information through a dedicated short-range communication, so as to achieve the collaborative collision avoidance early warning of the curve the goal of.

Description

A collaborative collision avoidance warning method for curves based on dedicated short-range communication

technical field

The invention relates to the technical field of dedicated short-range communication, in particular to a collaborative collision avoidance warning method for curves based on dedicated short-range communication.

Background technique

Curves are road sections where traffic accidents occur frequently, and the probability of accidents is high and the severity of accidents is high. On a road with a unit mileage, the number of accidents on curves is significantly higher than that on straight roads. This is because vehicles are prone to lane departure, vehicle collisions, or sideslips or even rollovers due to excessive speed when driving on curved roads. Waiting for danger. The frequent occurrence of accidents on curved road sections seriously restricts the improvement of the overall safety level of the highway. Statistics show that most of the traffic accidents on road curves are caused by the deviation of driving behavior. If the danger can be detected in advance and the driver is warned to take corresponding measures, the accidents on curves will be greatly reduced. However, the traditional forward collision warning system is very safe for vehicles traveling on straight roads, but powerless for vehicles traveling on curves. Especially at curves, due to obstacles such as buildings or mountains, the driver cannot observe whether there is a vehicle coming from the opposite side, and it is easy to cause a vehicle collision due to lane departure. If the driver can foresee the dangerous situation in advance, and make a corresponding decision to control the driving situation of the vehicle and at the same time send a warning signal to the other vehicle by some means, it will greatly reduce the probability of collision on the curve.

With the development of wireless communication technology, especially the dedicated short-range communication technology (DSRC) for inter-vehicle communication, and the maturity of satellite positioning technology, vehicles can perceive the surrounding driving conditions in a wider range, and realize the communication between vehicles and roads. information interaction.

Contents of the invention

The purpose of the present invention is to solve the above problems, using wireless communication technology and satellite positioning technology, combined with the state information of the vehicle, to propose a curve cooperative collision avoidance warning device and method based on dedicated short-range communication, thereby expanding the perception range of the vehicle, Timely detect oncoming vehicles that are out of sight at the curve, predict the minimum lateral distance when vehicles meet and the time to reach the meeting point, and realize assisted driving through hierarchical early warning methods to ensure driving safety.

A collaborative collision avoidance warning method for curves based on dedicated short-range communication, which is realized through the following steps:

Step 1: Identify the position of the ego vehicle;

Receive the position information of the self-vehicle in real time; compare the position information of the self-vehicle with the entrance position information of each curved road section on the electronic map; if the distance between the self-vehicle position and the entrance of the curved road section is less than the threshold d _curve , Then go to step 2; otherwise, go back to step 1.

Step 2: Judging whether there is a vehicle traveling in the opposite direction on the curved road section entered by the vehicle;

a. Obtain the driving information of the own car at the current moment, pack the driving information of the own car, and broadcast it to the surrounding; if the own car receives the driving information packets sent by other vehicles, then perform step b; if the own car does not receive other For the driving information packet sent by the vehicle, step ₆ is performed every time interval T1;

b. Analyze the driving information packet received by the own car according to the data format in step a; let the heading angle C _own ∈ (90°, 270°) of the own car, if the heading angle C in the driving information received by the own car _Other ∈ (270°, 360°) or C _Other ∈ (0°, 90°), then go to step 3; otherwise, execute step 6 every time T ₁ .

Step 3: Determine the minimum lateral distance between the ego vehicle and the opposite vehicle at the intersection;

A. Process the driving information of the own vehicle and the driving information of the opposite vehicle, let the own vehicle be A vehicle, and the opposite vehicle be B vehicle, then when A vehicle enters the entrance of the curve, take the position of A vehicle For the two-dimensional coordinate system xOy established for the origin, the south direction is taken as the positive direction of the y-axis, and the due west direction is the positive direction of the x-axis; thus, the initial position of the car A in the coordinate system xOy is (0, 0); B The initial position of the car in the coordinate system xOy is and:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In formula (1), LonA and LonB are the longitudes of car A and car B respectively; LatA and LatB are the latitudes of car A and car B respectively; R is the radius of the earth;

B. Keep the position of car B stationary, and car A moves relative to car B. After 1 second, car A will approach car B according to the trajectory of relative motion, and reach the They are:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, v _A and v _B are the driving speeds of cars A and B respectively; θ=270°-C _A +α _A ; δ=C _B +α _B ; C _A and C _B are the speeds of cars A and B respectively heading angle; α _A and α _B are the steering angles of car A and car B respectively;

C. Repeat step B, then after i seconds, car A will approach car B according to the trajectory of relative motion, and will arrive at They are:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, θ=270°-C _A +iα _A ; δ=C _B +iα _B ;

At this time, if Then return to step C; if Then go to step D;

D. Determine the distance d _{pre_side} from car B to line segment A _i-1 A _i is:

${\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; |</span>}{\sqrt{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

in, $k=\frac{{\mathrm{the\; y}}_{A_i-}{\mathrm{the\; y}}_{A_{i-1}}}{x_{A_i}-x_{A_{i-1}}}.$

Step 4: Determine the time required for the ego vehicle to meet the oncoming vehicle;

If the initial position of the oncoming vehicle is perpendicular to the line segment Ai- ₁ Ai, the vertical foot of the vertical line is point D, then the time t _{pre_side} required for the _ego vehicle and the oncoming vehicle to reach the intersection is:

${\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

in, $d_{A_{i-1}\mathrm{D.}}=\sqrt{{(x_{B_0}-x_{A_{i-1}})}^2+{({\mathrm{the\; y}}_{B_0}-{\mathrm{the\; y}}_{A_{i-1}})}^2-d_{pre\_\mathrm{the\; s}ide}^2}.$

Step 5: Collaborative collision avoidance early warning decision;

When two vehicles meet each other, the minimum safe distance in the lateral direction is d _{safe_min} ; thus, a graded early warning decision is made according to d _{pre_side} , t _{pre_side} and d _{safe_min} . The specific early warning methods are as follows:

Ⅰ. When d _{pre_side} ≤ d _{safe_min} , graded warning will be carried out according to the predicted collision time t _{pre_side} , specifically:

①. When t _{pre_side} > t _{level_3} , t _{level_3} is the vehicle intersection time threshold corresponding to level 3 warning, then set the warning level to level 3. At this time, the danger progress bar on the display screen of the self-vehicle is displayed as color A, and Prompt the driver by voice, and then perform step 6;

②. When t _{level_2} <t _{pre_side} <t _{level_3} , t _{level_2} is the vehicle intersection time threshold corresponding to the level 2 warning, and the warning level is set to level 2. At this time, the dangerous progress bar on the display screen of the self-vehicle terminal is displayed as color B , and prompt the driver by voice, then perform step 6;

③. When t _{pre_side} < t _{level_2} , set the warning level to level 1, then the dangerous progress bar on the display screen of the self-vehicle will be displayed as color B, and the driver will be prompted by voice. Vehicle B sends a warning message every time T2, and then executes step ₆ ;

Ⅱ. When d _{pre_side} > d _{safe_min} , it means that there is no danger of collision, and the self-vehicle does not perform cooperative collision avoidance warning, then go to step 6.

Step 6: Judging whether the ego vehicle leaves the curve;

According to the location information of the self-vehicle received by the GPS in real time, it is compared with the exit position information of the curved road section where the self-vehicle is located on the electronic map. If the distance between the self-vehicle and the exit of the curved road section is less than the threshold value d' _curve , end Collaborative collision avoidance warning; otherwise, return to step 1.

The advantages of the present invention are:

(1) The present invention uses vehicle-to-vehicle communication technology to solve the problem of "poor sight distance" caused by obstructions at curves, expand the vehicle's perception range, and timely assess the dangers of oncoming vehicles at curves. Assist the driver to know the information of the opposite vehicle at the curve, and avoid the collision of the opposite vehicle due to poor vision and lane departure;

(2) Based on vehicle-to-vehicle communication and positioning technology, the present invention proposes a collaborative early warning algorithm for curves, which can predict the minimum lateral distance when vehicles meet and the time required to reach the intersection, and provide quantification for collaborative collision avoidance warnings for curves parameters, effectively improving the accuracy of early warning.

Description of drawings

Fig. 1 is an application scene diagram of the collaborative collision avoidance warning method for curves of the present invention;

Fig. 2 is a flow chart of the collaborative collision avoidance warning method for curves of the present invention;

Fig. 3 is a schematic diagram of the curve collaborative collision avoidance warning algorithm of the present invention;

Fig. 4 is a structural block diagram of the vehicle terminal for implementing the method of collaborative collision avoidance and early warning for curves of the present invention.

In the picture:

1-Differential base station 2-Information collection part 3-Collaborative collision avoidance warning calculation part

4-Warning information display module 201-CAN information collection module 202-Satellite positioning module

203-Dedicated short-range communication module 301-Curve judgment module 302-Oncoming vehicle judgment module

303-Early warning algorithm module

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings.

A kind of curve collaborative collision avoidance warning method based on dedicated short-range communication, as shown in Figure 1, the scene aimed at is a curve, and there is an obstruction (such as a tall building or a mountain) at the curve, causing the driver's poor sight distance, Specifically, it is realized through the following steps, as shown in Figure 2:

Step 1: Identify the position of the ego vehicle;

Receive the location information of the own vehicle in real time, including the latitude and longitude data of the vehicle and the driving direction of the vehicle; combine the location information of the own vehicle with the position information (longitude and latitude) of the entrance of each curved road section on the electronic map (the entrance of the curved road section is determined by the driving direction of the vehicle) data) for comparison; if the distance between the self-vehicle and the entrance of the curved road section is less than the threshold value _dcurve (d _curve can be 1m), then the self-vehicle has entered the curved road section, and go to step 2; otherwise, return to step 1.

Step 2: Judging whether there is a vehicle traveling in the opposite direction on the curved road section entered by the vehicle;

a. Obtain the driving information of the self-vehicle at the current moment, including vehicle position information, heading, vehicle speed and steering angle, pack the driving information of the self-vehicle, and broadcast to the surroundings. The broadcast data format is: {longitude, latitude, course, steering, velocity}; where, longitude is longitude; latitude is latitude; course is course; steering is steering angle; velocity is vehicle speed. If the self-vehicle receives the driving information packets sent by other vehicles (vehicles other _than the self _- vehicle), then execute step b; 0.5s) Execute step 6 once.

b. Analyze the driving information packet received by the own vehicle according to the data format in step a, and obtain the driving information of the surrounding vehicles. Let the heading angle C _own ∈ (90°, 270°) of the own vehicle, if the heading angle C _Other ∈ (270°, 360°) or C _Other ∈ (0°, 90°) in the driving information received by the own vehicle, It means that there is an oncoming vehicle in the curved road section, and go to step 3; otherwise, it means that there is no oncoming vehicle in the curved road section, and step ₆ is performed every time T1 at this time. The above heading angle is defined as the angle between the clockwise direction from true north to the driving direction of the vehicle.

Step 3: Determine the minimum lateral distance between the ego vehicle and the oncoming vehicle when they meet;

A. Process the driving information of the own vehicle and the driving information of the opposite vehicle, let the own vehicle be A vehicle, and the opposite vehicle be B vehicle, then when A vehicle enters the entrance of the curve, take the position of A vehicle For the two-dimensional coordinate system xOy established for the origin, the south direction is taken as the positive direction of the y-axis, and the due west direction is the positive direction of the x-axis, as shown in Figure 3; thus, the initial position of the car A in the coordinate system xOy is ( 0, 0); the initial position of car B in the coordinate system xOy is and:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In formula (1), LonA and LonB are the longitudes of A and B cars respectively; LatA and LatB are the latitudes of A and B respectively; R is the radius of the earth, which is 6378137m.

B. Keep the position of car B stationary, and car A moves relative to car B. After 1 second, car A will approach car B according to the trajectory of relative motion, and reach the They are:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, v _A and v _B are the driving speeds of cars A and B respectively; θ=270°-C _A +α _A ; δ=C _B +α _B ; C _A and C _B are the speeds of cars A and B respectively heading angle; α _A and α _B are the steering angles of car A and car B respectively.

C. Repeat step B, then after i seconds, car A will approach car B according to the trajectory of relative motion, and will arrive at They are:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, v _A and v _B are the driving speeds of cars A and B respectively; θ=270°-C _A +iα _A ; δ=C _B +iα _B ; C _A and C _B are the speeds of cars A and B respectively heading angle; α _A and α _B are the steering angles of car A and car B respectively.

At this time, if Then return to step C; if Then go to step D.

D. Determine the distance d _{pre_side} from car B to line segment A _i-1 A _i is:

${\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; |</span>}{\sqrt{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

in, $k=\frac{{\mathrm{the\; y}}_{A_i}-{\mathrm{the\; y}}_{A_{i-1}}}{x_{A_i}-x_{A_{i-1}}}.$

Step 4: Determine the time required for the ego vehicle to meet with the opposite vehicle;

Let the point D be the foot of the vertical line drawn from the initial position of the oncoming vehicle to the line segment Ai- ₁ Ai, then the time t _{pre_side} required for the ego vehicle and the oncoming vehicle to reach the intersection is the _ego vehicle free The time it takes for the initial position to move to point D, then t _{pre_side} is:

${\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

in, $d_{A_{i-1}\mathrm{D.}}=\sqrt{{(x_{B_0}-x_{A_{i-1}})}^2+{({\mathrm{the\; y}}_{B_0}-{\mathrm{the\; y}}_{A_{i-1}})}^2-d_{pre\_\mathrm{the\; s}ide}^2}.$

Step 5: Collaborative collision avoidance warning decision;

According to the national standard, when two vehicles meet each other, the minimum safe distance in the lateral direction is v _own is the speed of the vehicle in m/s. Therefore, according to d _{pre_side} , t _{pre_side} and d _{safe_min} , a graded early warning decision is made. The specific early warning method is as follows:

Ⅰ. When d _{pre_side} ≤ d _{safe_min} , the graded warning will be carried out according to the predicted collision time t _{pre_side} , and the level of the warning level will be reflected by the change of the color of the progress bar and the frequency of voice broadcast, specifically:

①. When t _{pre_side} > t _{level_3} , t _{level_3} is the vehicle intersection time threshold corresponding to the 3-level warning, t _{level_3} can be taken as 10s, and the warning level is set as 3. At this time, the danger progress bar on the display screen of the self-vehicle is displayed as Color A (can be yellow), and prompt the driver to reduce the steering wheel angle by voice, so that the ego vehicle moves to the outside, and then execute step 6. The above voice prompt frequency is f _{level_3} .

② When t _{level_2} <t _{pre_side} <t _{level_3} , t _{level_2} is the vehicle intersection time threshold corresponding to the 2-level warning, t _{level_2} can be selected as 6s, and the warning level is set as 2. At this time, the danger progress bar on the display screen of the self-vehicle It is displayed in color B (may be red), and the driver is prompted by voice to reduce the steering wheel angle so that vehicle A moves to the outside, and then step 6 is performed. The above voice prompt frequency is f _{level_2} >f _{level_3} .

③. When t _{pre_side} < t _{level_2} , set the warning level to level 1, and the risk of vehicle collision is very high. On the one hand, the danger progress bar is displayed as color B through the display screen of the vehicle terminal at this time, and through the voice Prompt the driver to reduce the steering wheel angle so that vehicle A moves quickly to the outside; the voice prompt frequency is f _{level_1} > f _{level_2} ; at the same time, send a warning message to the opposite vehicle B every time T ₂ (T ₂ takes 0.5s) , and then go to step 6. The above warning information includes d _{pre_side} and t _{pre_side} obtained in step 3 and step 4, and the voice information requesting vehicle B to move the vehicle quickly to the inside.

Ⅱ. When d _{pre_side} > d _{safe_min} , it means that there is no danger of collision, and the self-vehicle does not perform cooperative collision avoidance warning, then go to step 6.

Step 6: Judging whether the ego vehicle leaves the curve;

According to the location information of the self-vehicle received by the GPS in real time, it is compared with the exit position information of the curved road section where the self-vehicle is located on the electronic map. If the distance between the self-vehicle and the exit of the curved road section is less than the threshold value d' _curve 1m), the self-vehicle has started to leave the curved road section, and the cooperative collision avoidance warning is terminated; otherwise, return to step 1.

The above-mentioned collaborative collision avoidance warning method based on dedicated short-range communication can be completed by combining a differential base station 1 with a set of vehicle-mounted equipment consisting of an information collection part 2, a cooperative collision avoidance warning calculation part 3 and a warning information display module 4, as shown in Figure 4 shown.

Among them, the differential base station 1 is set on the roadside of the curve, which can realize accurate differential positioning and ensure accurate positioning of the vehicle position. In the vehicle-mounted equipment: the information collection part 2 includes CAN information collection module 201, satellite positioning module 202, and short-range communication module 203; the satellite positioning module 202 realizes the differential positioning of the vehicle through the differential base station 1, and the specific method is: the satellite positioning module 202 obtains the vehicle position The information interacts with the vehicle position information acquired by the differential base station 1 that has accurately positioned the vehicle, and then corrects the vehicle position information acquired by the satellite positioning module 202, thereby reducing the vehicle positioning error of the satellite positioning module 202 and ensuring the positioning of the vehicle precision. The CAN information collection module 201 is used to extract the driving information of the vehicle, pack the driving information and send it to the curve judging module 301 . The dedicated short-range communication module 203 is used for real-time communication between vehicles.

The collaborative collision avoidance warning calculation part 3 includes a curve determination module 301, an oncoming vehicle determination module 302 and an early warning algorithm module 303; wherein, the curve determination module 301 stores an electronic map, combined with the received vehicle position information, Realize the judgment of whether the vehicle enters the curve in step 1. The oncoming vehicle determination module 302 is used to combine the determination results of the curve determination module 301 to realize the determination of whether there is an oncoming vehicle in the curve in step 2. The early warning algorithm module 303 is used to receive the driving information of the own vehicle and the oncoming vehicle, perform the calculation and judgment process in steps 2 to 5, and output the early warning of the own vehicle to the warning information display module 4 through the dedicated short-range communication module 203 Decision-making, through the warning information display part to perform warning information voice prompts and progress bar display operations according to the early warning decision; and through the dedicated short-range communication module 203 to the opposite driving vehicle, the minimum lateral distance at the time of rendezvous obtained by the early warning algorithm module 303 and the intersection point required time.

Claims (3)

1. A curve cooperative collision avoidance early warning method based on special short-range communication is characterized in that: the method is realized by the following steps:

step 1: judging the position of the vehicle;

receiving position information of a vehicle in real time; comparing the position information of the vehicle with the entrance position information of each curve road section on the electronic map; if the distance between the self-parking position and the entrance of the curve road section is smaller than the threshold value d_curveIf yes, executing step 2; otherwise, returning to execute the step 1;

step 2: judging whether opposite-direction running vehicles exist in a curve road section where the self vehicle enters;

a. acquiring the driving information of the vehicle at the current moment, packaging the driving information of the vehicle and broadcasting the packaged driving information to the periphery; if the self vehicle receives the running information packet sent by other vehicles, executing the step b; if the self vehicle does not receive the running information packet sent by other vehicles, the time interval T is set₁Step 6 is executed once;

b. b, analyzing the driving information packet received by the vehicle according to the data format in the step a; make course angle C of self-vehicle_ownE (90 degrees and 270 degrees), if the course angle C in the driving information received by the vehicle_OtherE (270 deg., 360 deg.) or C_OtherE, e (0 degrees and 90 degrees), entering the step 3; otherwise, every time T₁Step 6 is executed once;

and step 3: determining the minimum lateral distance between the self vehicle and the opposite-direction running vehicle at the intersection;

A. processing the running information of the vehicle and the running information of the opposite running vehicles to make the vehicle A as the vehicle A and the opposite running vehicle B as the vehicle B, and when the vehicle A enters the entrance of the curve, using the position of the vehicle AA two-dimensional coordinate system xOy is established for the origin, the south positive direction is taken as the positive direction of the y axis, and the west positive direction is taken as the positive direction of the x axis; thus, the initial position of the vehicle a in the coordinate system xOy is (0, 0); the initial position of the B vehicle in the coordinate system xOy isAnd:

<math> <mrow> <mo>{</mo> <mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>x</mi> <msub> <mi>B</mi> <mn>0</mn> </msub> </msub> <mo>=</mo> <mi>R</mi> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>a</mi> <mi>t</mi> <mi>B</mi> </mrow> <mo>)</mo> </mrow> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>o</mi> <mi>n</mi> <mi>B</mi> </mrow> <mo>)</mo> </mrow> <mo>-</mo> <mi>R</mi> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>a</mi> <mi>t</mi> <mi>A</mi> </mrow> <mo>)</mo> </mrow> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>o</mi> <mi>n</mi> <mi>A</mi> </mrow> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msub> <mi>y</mi> <msub> <mi>B</mi> <mn>0</mn> </msub> </msub> <mo>=</mo> <mi>R</mi> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>a</mi> <mi>t</mi> <mi>B</mi> </mrow> <mo>)</mo> </mrow> <mo>&times;</mo> <mi>sin</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>o</mi> <mi>n</mi> <mi>B</mi> </mrow> <mo>)</mo> </mrow> <mo>-</mo> <mi>R</mi> <mo>&times;</mo> <mi>cos</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>a</mi> <mi>t</mi> <mi>A</mi> </mrow> <mo>)</mo> </mrow> <mo>&times;</mo> <mi>sin</mi> <mrow> <mo>(</mo> <mrow> <mi>L</mi> <mi>o</mi> <mi>n</mi> <mi>A</mi> </mrow> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </mrow> </math>

in the formula (1), LonA and LonB are respectively the longitudes of the vehicle a and the vehicle B; LatA and LatB are the latitudes of the vehicle A and the vehicle B respectively; r is the radius of the earth;

B. the position of the vehicle B is fixed, the vehicle A moves relative to the vehicle B, and after 1 second, the vehicle A approaches the vehicle B according to the relative movement track and reaches the vehicle BRespectively as follows:

<math> <mrow> <mo>{</mo> <mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>x</mi> <msub> <mi>A</mi> <mn>1</mn> </msub> </msub> <mo>=</mo> <msub> <mi>x</mi> <msub> <mi>A</mi> <mn>0</mn> </msub> </msub> <mo>+</mo> <msub> <mi>v</mi> <mi>A</mi> </msub> <mo>*</mo> <mi>cos</mi> <mi>&theta;</mi> <mo>+</mo> <msub> <mi>v</mi> <mi>B</mi> </msub> <mo>*</mo> <mi>sin</mi> <mi>&delta;</mi> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msub> <mi>y</mi> <msub> <mi>A</mi> <mn>1</mn> </msub> </msub> <mo>=</mo> <msub> <mi>y</mi> <msub> <mi>A</mi> <mn>0</mn> </msub> </msub> <mo>+</mo> <msub> <mi>v</mi> <mi>A</mi> </msub> <mo>*</mo> <mi>sin</mi> <mi>&theta;</mi> <mo>+</mo> <msub> <mi>v</mi> <mi>B</mi> </msub> <mo>*</mo> <mi>cos</mi> <mi>&delta;</mi> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow> </mrow> </math>

wherein v is_AAnd v_BRespectively the driving speeds of the A vehicle and the B vehicle; theta 270-C_A+α_A；＝C_B+α_B；C_AAnd C_BRespectively are the course angles of the A vehicle and the B vehicle; alpha is alpha_AAnd alpha_BRespectively are the steering angles of the A vehicle and the B vehicle;

C. step B is repeatedly executed, and after i seconds, the vehicle A is relatively transportedThe moving track approaches to the B vehicle and will arriveRespectively as follows:

<math> <mrow> <mo>{</mo> <mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>x</mi> <msub> <mi>A</mi> <mi>i</mi> </msub> </msub> <mo>=</mo> <msub> <mi>x</mi> <msub> <mi>A</mi> <mrow> <mi>i</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> </msub> <mo>+</mo> <msub> <mi>v</mi> <mi>A</mi> </msub> <mo>*</mo> <mi>cos</mi> <mi>&theta;</mi> <mo>+</mo> <msub> <mi>v</mi> <mi>B</mi> </msub> <mo>*</mo> <mi>sin</mi> <mi>&delta;</mi> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msub> <mi>y</mi> <msub> <mi>A</mi> <mi>i</mi> </msub> </msub> <mo>=</mo> <msub> <mi>y</mi> <msub> <mi>A</mi> <mrow> <mi>i</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> </msub> <mo>+</mo> <msub> <mi>v</mi> <mi>A</mi> </msub> <mo>*</mo> <mi>sin</mi> <mi>&theta;</mi> <mo>+</mo> <msub> <mi>v</mi> <mi>B</mi> </msub> <mo>*</mo> <mi>cos</mi> <mi>&delta;</mi> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </mrow> </mrow> </math>

wherein, theta is 270-C_A+iα_A；＝C_B+iα_B；

At this time, ifReturning to execute the step C; if it isEntering the step D;

D. determining a vehicle-to-line segment A_i-1A_iDistance d of_{pre_side}Comprises the following steps:

$d_{pre\_side}=\frac{\left|{\mathrm{kx}}_{B_0}-y_{B_0}-{\mathrm{kx}}_{A_{i-1}}+y_{A_{i-1}}\right|}{\sqrt{k^2+1}}---\left(4\right)$

wherein, $k=\frac{y_{A_i}-y_{A_{i-1}}}{x_{A_i}-x_{A_{i-1}}};$

and 4, step 4: determining the time required for the self vehicle to meet the opposite driving vehicle;

let the initial position of the oncoming vehicle be directed to line segment A_i-1A_iThe vertical line is D, the time t required for the self vehicle and the opposite running vehicle to reach the intersection is_{pre_side}Comprises the following steps:

$t_{pre\_side}=i-1+d_{A_{i-1}D}/d_{A_i{A}_{i-1}}---\left(5\right)$

wherein, $d_{A_{i-1}D}=\sqrt{{(x_{B_0}-x_{A_{i-1}})}^2+{(y_{B_0}-y_{A_{i-1}})}^2-d_{pre\_side}^2};$

and 5: collaborative collision avoidance early warning decision;

when two vehicles meet, the minimum lateral safety distance is d_{safe_min}(ii) a Thereby according to d_{pre_side}、t_{pre_side}And d_{safe_min}And (3) carrying out grading early warning decision, wherein the specific early warning mode is as follows:

i, when d_{pre_side}≤d_{safe_min}Then according to the predicted collision time t_{pre_side}Carrying out grading early warning, specifically:

when t is_{pre_side}＞t_{level_3}When t is_{level_3}If the vehicle crossing time threshold corresponding to the 3-level early warning is adopted, the early warning level is set to be 3, at the moment, the dangerous progress bar of the vehicle-mounted end display screen of the self vehicle is displayed in a color A, the driver is prompted through voice, and then the step 6 is executed;

when t is_{level_2}＜t_{pre_side}＜t_{level_3}When t is_{level_2}Setting the early warning level as level 2 if the vehicle crossing time threshold corresponding to the level 2 early warning is adopted, displaying the dangerous progress bar of the display screen at the vehicle-mounted end of the vehicle as color B, prompting the driver through voice, and following the dangerous progress barThen step 6 is executed;

(iii) when t_{pre_side}＜t_{level_2}If the early warning level is set to be level 1, displaying the dangerous progress bar of the display screen of the self-vehicle as a color B, and prompting a driver through voice; at the same time, the vehicle B running in opposite directions is communicated in a special short-range mode at intervals of time T₂Sending the warning information once, and then executing the step 6;

II, when d_{pre_side}＞d_{safe_min}If no collision danger exists, and the self vehicle does not perform cooperative collision avoidance early warning, executing the step 6;

step 6: judging whether the vehicle is driven away from the bend or not;

according to the position information of the vehicle received by the GPS in real time, comparing the position information with the exit position information of the curve road section where the vehicle is located on the electronic map, and if the distance between the vehicle and the exit of the curve road section is smaller than a threshold value d'_curveFinishing the cooperative collision avoidance early warning; otherwise, returning to execute the step 1.

2. A curve cooperative collision avoidance early warning method based on dedicated short-range communication as claimed in claim 1, wherein: in step 5, when t is reached_{pre_side}＞t_{level_3}At a time, the voice prompt frequency is f_{level_3}(ii) a When t is_{level_2}＜t_{pre_side}＜t_{level_3}At a time, the voice prompt frequency is f_{level_2}(ii) a When t is_{pre_side}＜t_{level_2}At a time, the voice prompt frequency is f_{level_1}(ii) a And f is_{level_1}＞f_{level_2}＞f_{level_3}。

3. A curve cooperative collision avoidance early warning method based on dedicated short-range communication as claimed in claim 1, wherein: in step 5, when the early warning level is level 1, the warning information sent by the vehicle to the vehicle running oppositely comprises d_{pre_side}、t_{pre_side}And voice prompts.