CN104325978A - Safety anti-collision early warning method based on vehicular ad-hoc network - Google Patents

Abstract

The invention discloses a safety anti-collision early warning method based on a vehicular ad-hoc network. The method comprises the steps that a vehicle-mounted terminal obtains location information and running state information of a vehicle; the location information and the running state information of the vehicle are transmitted when the vehicle brakes; if the vehicle-mounted terminal monitors the location information and running state information of a vehicle ahead, the vehicle-mounted terminal calculates the actual distance between the two vehicles, the safety distance of the two vehicles and the danger coefficient; the vehicle-mounted terminal conducts early warming processing according to the magnitude of the danger coefficient and gives out voice prompts to a driver. The safety anti-collision early warning method based on the vehicular ad-hoc network is particularly applicable to vehicles which run on expressways, can improve running safety and can reduce collision accidents on the expressways.

Description

A kind of safe anticollision method for early warning based on car networking

Technical field

The invention belongs to technical field of vehicle safety, be specifically related to a kind of safe anticollision method for early warning based on car networking.

Background technology

In car networking (Vehicular Ad-hoc Network, VANET), the vehicle of high-speed mobile, by the form Real-Time Sharing traffic information of wireless self-organization network, improves drive safety.

Recently, on express highway, frequent generation vehicle pileup accidents, brings huge economic loss to the country and people.How to improve traffic safety, reduce accident rate and become a vital problem.On a highway, accident is normally by front truck emergency braking, and rear car has little time to react and causes.This be because the speed of a motor vehicle on express highway is fast, spacing is far away, the impact of reaction time short and weather condition (as dense fog, heavy rain and heavy snow), chaufeur is often difficult to the running state noticing surrounding vehicles, finally leads to a disaster.

Summary of the invention

The object of the invention is to provide a kind of safe anticollision method for early warning based on car networking, is specially adapted to the vehicle of highway driving, can improves traffic safety, reduce the collision case of express highway.

For achieving the above object, technical scheme of the present invention is: a kind of safe anticollision method for early warning based on car networking, comprises the following steps:

(1) car-mounted terminal obtains location information and the running condition information of this car vehicle, when this car vehicle brake, sends location information and the running condition information of this car vehicle;

(2) if car-mounted terminal monitors location information and the running condition information of front vehicles, car-mounted terminal calculates the actual distance dis between two cars, the safety distance sd of two cars and danger coefficient β;

(3) car-mounted terminal carries out early warning process according to danger coefficient size, and sends voice message to chaufeur.

Preferably, described location information at least comprises longitude and latitude, ground course angle, time; Described running condition information at least comprises travel direction and acceleration/accel.

Preferably, the context of vehicle is drawn by following formula:

$\left\{\begin{array}{c}(\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecour\; se}1+45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R<0\\ (\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecour\; se}1-45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R>0\end{array}\right.$

Wherein radLat1 and radLat2 represents the latitude of two cars respectively, radLon1 and radLon2 represents the longitude of two cars respectively, and Surfacecourse1 represents the ground course angle of this car vehicle, and R represents earth radius constant.

Preferably, described two car actual distance dis calculate according to the latitude and longitude coordinates of vehicle, and computing formula is:

$\mathrm{dis}=2\&times;\arcsin \left(\sqrt{{\sin }^2\left(\frac{\mathrm{radLat}1-\mathrm{radLat}2}{2}\right)+\cos \left(\mathrm{radLat}1\right)\&times;\cos \left(\mathrm{radLat}2\right)\&times;{\sin }^2\left(\frac{\mathrm{radLon}1-\mathrm{radLon}2}{2}\right)}\right)\&times;R$

Wherein, radLat1 and radLat2 represents the latitude of two cars respectively, radLon1 and radLon2 represents the longitude of two cars respectively, and R represents earth radius constant.

Preferably, the computing formula of the safety distance sd of described two cars is:

sd＝T*|v ₁-v ₂|；

Wherein v ₁this car speed of a motor vehicle, v ₂be the front truck speed of a motor vehicle, T is the reaction time.

Preferably, described speed of a motor vehicle v calculates according to latitude and longitude coordinates, and computing formula is:

$v=\frac{2*R*\arcsin \left(\sqrt{{\sin }^2\left(\frac{\mathrm{radLat}1-\mathrm{radLat}2}{2}\right)+\cos \left(\mathrm{radLat}1\right)\&times;\cos \left(\mathrm{radLat}2\right)\&times;{\sin }^2\left(\frac{\mathrm{radLon}1-\mathrm{radLon}2}{2}\right)}\right)}{t_2-t_1}$

Wherein, t ₂and t ₁represent current time and last time respectively, radLat1 and radLat2 represents the latitude of a position and the latitude of current location respectively, radLon1 and radLon2 represents the longitude of a position and the longitude of current location respectively, and R represents earth radius constant.

Preferably, described danger coefficient β computing formula is:

$\mathrm{\&beta;}=\frac{\mathrm{sd}-\mathrm{dis}}{\mathrm{dis}}.$

Present invention also offers a kind of safe collision early warning system based on car networking, comprise the acceleration information of collection vehicle and judge the acceleration module whether vehicle brakes; Collection vehicle location information and judge the GPS module of distance of this car and brake vehicle; For the wireless communication module of communication and information processing; For the voice module of alarm.

Relative to scheme of the prior art, advantage of the present invention is:

1. this method utilizes car to network Real-time Communication Technology to obtain relevant information, constantly can obtain the up-to-date gps data of adjacent car, and calculate its speed of a motor vehicle, make error less;

2. this method utilizes wireless module to carry out data processing, decreases the volume of system, is convenient to dispose under highway environment;

3. the early warning information of adjacent car is kept in priority query by this method, and the information selecting danger coefficient maximum processes, and give chaufeur and report to the police, practicality is higher;

4. the Applicable scope of this method is comparatively large, can reliably use at the inclement weather such as thick fog, severe snow.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described:

Fig. 1 is application scenarios schematic diagram of the present invention;

Fig. 2 is the diagram of circuit of the safe anticollision method for early warning that the present invention is based on car networking;

Fig. 3 is the graticules schematic diagram of the safe anticollision method for early warning that the present invention is based on car networking;

Fig. 4 be the present invention is based on car networking safe anticollision method for early warning judge vehicle front and back position schematic diagram by longitude and latitude;

Fig. 5 is that the coordinate of two cars of the safe anticollision method for early warning that the present invention is based on car networking represents schematic diagram.

Detailed description of the invention

For making the object of invention, technical scheme and advantage clearly understand, below in conjunction with detailed description of the invention and with reference to accompanying drawing, invention is further described.Should be appreciated that, these describe just exemplary, and do not really want to limit the scope of the invention.In addition, in the following description, the description to known features and technology is eliminated, to avoid unnecessarily obscuring concept of the present invention.

Embodiment:

The present embodiment based on car networking safe collision early warning system in car-mounted terminal obtain gps data with 1HZ frequency, calculate this car moving velocity, obtain this car acceleration information with fixed frequency (as 5HZ) from acceleration module.When vehicle brake, by being carried out to exchange with the car-mounted terminal of surrounding vehicles the GPS information of self by real-time wireless communication, comprise the information such as course, ground, latitude and longitude coordinates, speed, acceleration/accel.

As shown in Figure 1, during current vehicle brake, the early warning information of front truck will be received from car.From car by performing the method for the express highway active safety system of networking based on car, corresponding information being processed, and sends phonetic warning information to chaufeur when needed.

As shown in Figure 2, the method comprises the following steps:

(1) the GPS sensor of car-mounted terminal obtains the location information (longitude and latitude, ground course angle, time) of vehicle, calculates vehicle current driving speed v by GPS information.The acceleration pick-up of car-mounted terminal obtains the running condition information (acceleration/accel) of vehicle;

(2) when vehicle brake, send from the information such as GPS location, moving velocity, travel direction of car to surrounding vehicles afterwards;

(3) if (front truck acceleration/accel is less than threshold value A in front truck brake _d) time, the actual distance dis that this car vehicle will calculate according to the latitude and longitude coordinates of front truck vehicle and Ben Che vehicle between two cars, and the safety distance sd calculating two cars according to the speed of a motor vehicle difference of two cars, and calculate danger coefficient β;

(4) select the maximum early warning information of danger coefficient to process from car vehicle, and corresponding voice message is sent to chaufeur.

Calculate two car actual distance dis according to the latitude and longitude coordinates of this car vehicle and the latitude and longitude coordinates of adjacent vehicle in step (3), formula is:

$\mathrm{dis}=2\&times;\arcsin \left(\sqrt{{\sin }^2\left(\frac{\mathrm{radLat}1-\mathrm{radLat}2}{2}\right)+\cos \left(\mathrm{radLat}1\right)\&times;\cos \left(\mathrm{radLat}2\right)\&times;{\sin }^2\left(\frac{\mathrm{radLon}1-\mathrm{radLon}2}{2}\right)}\right)\&times;R---\left(I\right)$

Wherein, radLat1 and radLat2 represents the latitude of two cars respectively, radLon1 and radLon2 represents the longitude of two cars respectively, and R represents earth radius constant.

Calculate this car speed of a motor vehicle v according to the latitude and longitude coordinates of this car vehicle and the latitude and longitude coordinates of adjacent vehicle in step (1), formula is:

$v=\frac{2*R*\arcsin \left(\sqrt{{\sin }^2\left(\frac{\mathrm{radLat}1-\mathrm{radLat}2}{2}\right)+\cos \left(\mathrm{radLat}1\right)\&times;\cos \left(\mathrm{radLat}2\right)\&times;{\sin }^2\left(\frac{\mathrm{radLon}1-\mathrm{radLon}2}{2}\right)}\right)}{t_2-t_1}---\left(\mathrm{II}\right)$

Wherein, t ₂and t ₁represent current time and last time respectively, radLat1 and radLat2 represents the upper latitude of a position and the latitude of current location of this car respectively, radLon1 and radLon2 represents the upper longitude of a position and the longitude of current location of this car respectively, and R represents earth radius constant;

In step (3), whether surrounding vehicles obtains by calculating vehicle context in the traveling front of this car vehicle, and formula is:

$\left\{\begin{array}{c}(\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecour\; se}1+45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R<0\\ (\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecour\; se}1-45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R>0\end{array}\right.---\left(\mathrm{III}\right)$

Wherein, radLat1 and radLat2 represents the latitude of two cars respectively, radLon1 and radLon2 represents the longitude of two cars respectively, and Surfacecourse1 represents the ground course angle of vehicle, and R represents earth radius constant.

The formula calculating the safety distance sd of two cars in step (3) is:

sd＝T*|v ₁-v ₂| (IV)

Wherein, v ₁from the car speed of a motor vehicle, v ₂be the adjacent car speed of a motor vehicle, T is the reaction time.

The formula calculating the danger coefficient β of two cars is:

$\mathrm{\&beta;}=\frac{\mathrm{sd}-\mathrm{dis}}{\mathrm{dis}}---\left(V\right)$

Concrete, utilize the principle of the calculating of the latitude and longitude coordinates in gps data car euclidean distance between node pair as follows:

On graticules figure, distance between calculation 2 can be measured according to longitude and latitude.The gap length that all parts of the world latitude is 1 ° all equal (because the length of all warps is all equal) is approximately 111km/1 °.On equator, longitude 1 ° of correspondence arc length on the ground is approximately also 111km.Because each parallel successively decreases from equator to the two poles of the earth, the length on 60 ° of parallels is the half on equator, so the arc length of difference of longitude 1 ° is just unequal on each parallel.Actual arc same parallel (supposed that the latitude of this parallel is α) longitude 1 ° is corresponding is grown up and is about 111cos α km.Therefore, as long as be aware of the difference of latitude between any two places, or the difference of longitude of any two places on equator, just can calculate the actual distance between them.The judgement of closest range between two places: if two places difference of longitude equals 180 °, then the great circle crossing two places is through coil, and two places closest range is the minor arc crossing two limits in great circle; If two places difference of longitude is not equal to 180 °, then crossing the great circle of two places is not through coil, and with through coil oblique, two places closest range only limit, but cross two places.As shown in Figure 3, A, B represent the position of two cars respectively, and Latitude-Longitude is expressed as (a1, a2), (b1, b2), and radLat1, radLon1 be corresponding a1, a2 respectively; RadLat2, radLon2 be corresponding b1, b2 respectively, and the formula calculating two spacings according to the latitude and longitude coordinates of two cars is:

$\mathrm{dis}=2\&times;\arcsin \left(\sqrt{{\sin }^2\left(\frac{\mathrm{radLat}1-\mathrm{radLat}2}{2}\right)+\cos \left(\mathrm{radLat}1\right)\&times;\cos \left(\mathrm{radLat}2\right)\&times;{\sin }^2\left(\frac{\mathrm{radLon}1-\mathrm{radLon}2}{2}\right)}\right)\&times;R---\left(I\right)$

Wherein, radLat1 and radLat2 represents the latitude (unit is radian) of two cars respectively, and radLon1 and radLon2 is respectively longitude (unit is radian), and R represents earth radius constant 6378.137km.

After having introduced the principle of calculating vehicle node spacing, the formula (II) utilizing GPS to calculate car speed just can be proposed smoothly.The molecular moiety of formula (II) represents the distance of current vehicle position and last position, and denominator represents the time gap of twice collection gps data.

Before and after vehicle, relative position detailed schematic is as follows to utilize gps data to judge:

As shown in Figure 4, the relative position of Ben Cheche and adjacent car can calculate with longitude and latitude.Due to two spacings little (compared to the earth), so it is in the same plane to regard two cars as.As shown in Figure 5, with from car for the origin of coordinates, take direct north as x-axis positive dirction, with positive west for y-axis positive dirction sets up coordinate axle; The coordinate (x, y) of so adjacent car calculates by the difference of two car longitudes and latitudes:

$\left\{\begin{array}{c}x=(\mathrm{radLon}2-\mathrm{radLon}1)\&times;R\\ y=(\mathrm{radLon}2-\mathrm{radLon}1)\&times;R\end{array}\right.$

This car travel direction is the ground course angle surfacecourse1 of this car, the ɑ namely in Fig. 5; So can be determined by 2 rays with the region being in this car and travelling front, the region namely between L1 and L2, wherein the slope of L1 and L2 is respectively tan (surfacecourse1+45), tan (surfacecourse1-45).This region can be expressed with the analytic expression of L1 and L2, namely

$\left\{\begin{array}{c}(\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecour\; se}1+45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R<0\\ (\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecour\; se}1-45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R>0\end{array}\right.---\left(\mathrm{III}\right)$

Above-mentioned example, only for technical conceive of the present invention and feature are described, its object is to person skilled in the art can be understood content of the present invention and implement according to this, can not limit the scope of the invention with this.All equivalent transformations of doing according to Spirit Essence of the present invention or modification, all should be encompassed within protection scope of the present invention.

Claims (8)

1., based on a safe anticollision method for early warning for car networking, it is characterized in that, comprise the following steps:

(1) car-mounted terminal obtains location information and the running condition information of this car vehicle, when this car vehicle brake, sends location information and the running condition information of this car vehicle;

(2) if car-mounted terminal monitors location information and the running condition information of front vehicles, car-mounted terminal calculates the actual distance dis between two cars, the safety distance sd of two cars and danger coefficient β;

(3) car-mounted terminal carries out early warning process according to danger coefficient size, and sends voice message to chaufeur.

2. the safe anticollision method for early warning based on car networking according to claim 1, it is characterized in that, described location information at least comprises longitude and latitude, ground course angle, time; Described running condition information at least comprises travel direction and acceleration/accel.

3. the safe anticollision method for early warning based on car networking according to claim 1, it is characterized in that, the context of vehicle is drawn by following formula:

$\left\{\begin{array}{c}(\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecourse}1+45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R<0\\ (\mathrm{radLon}2-\mathrm{radLon}1)\&times;R-\tan (\mathrm{Sur\; facecoursr}1-45)\&times;(\mathrm{radLat}2-\mathrm{radLat}1)\&times;R>0\end{array}\right.$

Wherein radLat1 and radLat2 represents the latitude of two cars respectively, radLon1 and radLon2 represents the longitude of two cars respectively, and Sur facecousel represents the ground course angle of this car vehicle, and R represents earth radius constant.

4. the safe anticollision method for early warning based on car networking according to claim 1, it is characterized in that, described two car actual distance dis calculate according to the latitude and longitude coordinates of vehicle, and computing formula is:

$\mathrm{dis}=2\&times;\arcsin \left(\sqrt{{\sin }^2\left(\frac{\mathrm{radLat}1-\mathrm{radLat}2}{2}\right)+\cos \left(\mathrm{radLat}1\right)\&times;\cos \left(\mathrm{radLat}2\right)\&times;{\sin }^2\left(\frac{\mathrm{radLon}1-\mathrm{radLon}2}{2}\right)}\right)\&times;R$

Wherein, radLat1 and radLat2 represents the latitude of two cars respectively, radLon1 and radLon2 represents the longitude of two cars respectively, and R represents earth radius constant.

5. the safe anticollision method for early warning based on car networking according to claim 1, it is characterized in that, the computing formula of the safety distance sd of described two cars is:

sd＝T*|υ ₁-υ ₂|；

Wherein v ₁this car speed of a motor vehicle, v ₂be the front truck speed of a motor vehicle, T is the reaction time.

6. the safe anticollision method for early warning based on car networking according to claim 5, it is characterized in that, described speed of a motor vehicle υ calculates according to latitude and longitude coordinates, and computing formula is:

$\mathrm{\&upsi;}=\frac{2*R*\arcsin \left(\sqrt{{\sin }^2\left(\frac{\mathrm{radLat}1-\mathrm{radLat}2}{2}\right)+\cos \left(\mathrm{radLat}1\right)*\cos \left(\mathrm{radLat}2\right)*{\sin }^2\left(\frac{\mathrm{radLon}1-\mathrm{radLon}2}{2}\right)}\right)}{t_2-t_1}$

Wherein, t ₂and t ₁represent current time and last time respectively, radLat1 and radLat2 represents the latitude of a position and the latitude of current location respectively, radLon1 and radLon2 represents the longitude of a position and the longitude of current location respectively, and R represents earth radius constant.

7. the safe anticollision method for early warning based on car networking according to claim 1, its feature exists

In, described danger coefficient β computing formula is:

$\mathrm{\&beta;}=\frac{\mathrm{sd}-\mathrm{dis}}{\mathrm{dis}}.$

8., based on a safe collision early warning system for car networking, it is characterized in that, comprise the acceleration information of collection vehicle and judge the acceleration module whether vehicle brakes; Collection vehicle location information and judge the GPS module of distance of this car and brake vehicle; For the wireless communication module of communication and information processing; For the voice module of alarm.