CN106289271A - A kind of bend vehicle locating device and method - Google Patents

Abstract

The present invention provides a curved vehicle positioning device and method, wherein the device includes: a laser scanning unit and a central processing unit; the laser scanning unit is used to collect the ranging waveform in the curved area in real time; the central processing A unit, connected to the laser scanning unit, used to receive the ranging waveform in the curve area sent by the laser scanning unit, and perform coordinate conversion, interference elimination and area search on the ranging waveform of the current frame, and determine the vehicle area corresponding to the current frame. The scanning point position information; the vehicle area of the current frame is matched with the vehicle area of the previous frame, and it is determined that the vehicle area of the current frame corresponds to the new vehicle entering the curve or the vehicle traveling in the curve area; according to the vehicle area corresponding to the current frame Scan point location information, obtain and output vehicle real-time positioning parameters. The present invention has real-time positioning, high positioning accuracy and rich positioning information, and can solve the problem of safely passing through curves in assisted driving or unmanned driving.

Description

Device and method for positioning a curved vehicle

technical field

The invention relates to the field of computer technology, in particular to a device and method for positioning a curved vehicle.

Background technique

Assisted driving and unmanned driving are currently key research topics in the fields of automobile manufacturing, traffic safety and intelligent transportation. As a key technology in assisted driving and unmanned driving, vehicle positioning has become the top priority.

Vehicle positioning during operation can be roughly divided into straight road positioning and curve positioning. As the most common road alignment, the straight road can be easily realized through visual straight road keeping or GPS positioning. Due to the influence of its curvature, there is a certain degree of difficulty in positioning and lane keeping. When the vehicle is driving in a curve, whether it is used as an early warning reminder for assisted driving or a positioning service for unmanned driving, there are parameters as shown in Figure 1 that need to be provided. Among them, the turning radius ρ=O′P, the arc length distance from the front of the car to the stop line when exiting the bend is The arc length from the rear of the car to the stop line at exit is The angle between the front and the stop line α=∠HO'S, the angle between the rear and the stop line β=∠TO'S, the linear velocity ν when the vehicle turns, and the angle θ between the side of the vehicle body and the Y-axis direction.

Currently commonly used technical means and methods are: image vision technology, GPS positioning technology, wireless signal strength method, RFID positioning method and map and differential navigation method.

The image vision method uses an image sensor to extract the lane boundary line by collecting the road markings in front of the vehicle, so as to determine the position of the vehicle roughly within the lane from the boundary line. This type of method is more suitable for lane keeping in straight roads, but it cannot quickly and accurately obtain the turning curvature due to the limited field of view in curves, and cannot predict the distance from the exit of the curve at the next moment.

GPS positioning technology has outstanding advantages in vehicle navigation, but there is a problem of insufficient positioning accuracy in curve positioning, especially when the curvature of the curve changes greatly, GPS positioning can only roughly determine whether the vehicle enters the curve and whether the vehicle leaves the curve .

The wireless signal strength method is to determine the approximate location of the vehicle by matching the strength of the mobile phone WIFI or other wireless network signals with the distance. The method of combining distance and wireless signal strength has a certain practical value in the field of Internet of Vehicles for determining the relative position between vehicles, but it is of little significance to ignore road information in curve positioning.

The RFID positioning method provides location information by placing passive electronic tags on key coordinate nodes of the road. This type of method can only provide whether the vehicle has passed the key point and determine the position of the vehicle through several key points, and then use the key point information to describe the vehicle's driving trajectory. The RFID positioning method is of great practical value in locating goods in libraries or supermarkets. If you want to locate vehicles on curves, you need more key points and provide too little curve positioning information.

The map and differential navigation method is to increase the positioning accuracy by adding a differential navigation module to the vehicle, and then match it with the map information to determine the position of the vehicle in the curve. Compared with the GPS positioning method, the positioning accuracy of this method is greatly improved, and the specific coordinate value of the vehicle on the curve can be determined. However, differential navigation has the problem that the update speed of positioning information is not timely enough, and the output is also the coordinate information of the curve, which lacks the positional relationship of the body posture relative to the curve curve and the feedback of the turning radius.

Among the above methods: the image vision method has outstanding advantages in maintaining straight lanes; the GPS positioning method has insufficient positioning accuracy in curved roads; the wireless signal strength method is feasible for vehicle relative position detection, ignoring the feedback of vehicle road information; In the implementation of curves, more passive electronic tags are required as key coordinate points, and the location information provided is single; the map and differential navigation method have high practical value and high positioning accuracy in straight roads and curves, but there is a problem of untimely positioning refresh , and information such as the vehicle pose cannot be given.

Therefore, it is urgent to find a method with real-time positioning, high precision, and rich positioning information to solve the problem of safely passing through curves in assisted driving or unmanned driving.

Contents of the invention

Aiming at the defects of the prior art, the present invention provides a curved vehicle positioning device and method with real-time positioning, high precision, and rich positioning information, which can solve the problem of safely passing the curve in assisted driving or unmanned driving.

In a first aspect, the present invention provides a device for positioning a vehicle on a curve, said device comprising: a laser scanning unit and a central processing unit;

The laser scanning unit is fixed on the installation pole, and is located at the center point inside the curve or the extension line outside the radius of the curve at a preset distance from the lane boundary line, and is used for real-time acquisition of ranging waveforms in the curve area;

The central processing unit is connected with the laser scanning unit, and is used to receive the ranging waveform in the curve area sent by the laser scanning unit, and perform coordinate transformation, interference elimination and area search on the ranging waveform of the current frame to determine the current Scanning point position information corresponding to the frame vehicle area; area matching is performed between the current frame vehicle area and the previous frame vehicle area, and it is determined that the current frame vehicle area corresponds to a new vehicle entering the curve or a vehicle traveling in the curve area; according to the current frame The location information of the scanning point corresponding to the vehicle area, obtains and outputs the real-time positioning parameters of the vehicle.

Preferably, when the laser scanning unit is located at a preset distance from the extension line outside the radius of the curve to the boundary line of the lane, the preset distance is greater than or equal to 2000 mm;

The height of the laser scanning unit from the road surface is greater than or equal to 700mm and less than or equal to 850mm;

The laser scanning unit uses scanning frequency f and scanning angle resolution Scanning parallel to the plane where the road surface is located; preferably, the scanning frequency f=50Hz,

The scanning angle range of the laser scanning unit in each scanning period is 0-270°.

In a second aspect, the present invention provides a method for positioning a curved vehicle, the method comprising:

The laser scanning unit collects the ranging waveform in the curve area in real time;

The central processing unit receives the ranging waveform in the curve area sent by the laser scanning unit, and performs coordinate conversion, interference elimination and area search on the ranging waveform of the current frame to determine the scanning point position information corresponding to the vehicle area of the current frame;

The central processing unit performs area matching on the vehicle area of the current frame and the vehicle area of the previous frame, and determines that the vehicle area of the current frame corresponds to a new vehicle entering the curve or a vehicle traveling in the curve area;

The central processing unit obtains and outputs real-time vehicle positioning parameters according to the scanning point position information corresponding to the vehicle area in the current frame.

Preferably, the method also includes:

The central processing unit tracks the new vehicle entering the curve in real time, so as to remove the vehicle when the new vehicle entering the curve leaves the curve area.

Preferably, the coordinate transformation includes:

According to the formula, coordinate conversion is performed on the ranging waveform of the current frame:

Among them, i is the serial number of the scanning point, L(i) is the distance from the scanning point i to the center point of the laser scanning unit, n ₀ is the serial number of the emitting point where the emitted light coincides with the ox axis in the laser scanning unit, is the scanning angular resolution of the laser scanning unit, x(i) is the abscissa of scanning point i in the oxy rectangular coordinate system, and y(i) is the vertical coordinate of scanning point i in the oxy rectangular coordinate system.

Preferably, the interference elimination includes:

Step 1: Calculate the distance L′(i) from scanning point i to the center of the inner circle of the curve according to formula 2:

Step 2: Calculate the angle Q(i) between the scan point i and the line where the center of the circle inside the curve is located and the radius of the ox axis according to formula 3:

Among them, the center point of the laser scanning unit is the coordinate system circle point o, the side of the laser scanning unit is the coordinate axis oy, and the vertical line passing through the o point of the y axis is the ox axis;

Step 3: According to Q(i) and L'(i), use formula 4 to exclude the scanning points that are not in the curve and not in the range of the curve lane:

Among them, R ₁ is the radius of the arc segment near the center of the curve, R ₂ is the radius of the arc segment far from the center of the curve, and Q ₁ is the distance between the starting point of the curve and the line where the center of the inner circle of the curve is located and the radius of the ox axis. Included angle, Q ₂ is the angle between the end point of the curve and the straight line where the inner center of the curve is located and the radius of the ox axis.

Preferably, the area search includes:

Determine the boundary point corresponding to the current frame vehicle area and the point to which the vehicle area belongs according to the scan point coordinates after interference elimination:

If x(i-1)=0 and x(i)>0, then it is determined that scanning point i is the initial boundary point of the vehicle area;

If x(i-1)>0 and x(i)>0, it is determined that the scan point i belongs to the area where the scan point i-1 is located;

If x(i)>0 and x(i+1)=0, it is determined that scanning point i is the end boundary point of the vehicle area.

Preferably, the area matching of the current frame vehicle area and the previous frame vehicle area, and determining that the current frame vehicle area corresponds to a new vehicle entering a curve or a vehicle traveling in a curve area includes:

According to the boundary range relationship between the vehicle area in the current frame and the vehicle area in the previous frame, identify new vehicles entering the curve or track vehicles traveling in the curve area:

If the current frame vehicle area (S _Q (Qmin, Qmax), S _L′ (L′min, L′max)) and the previous frame vehicle area (S′ _Q (Qmin, Qmax), S′ _L′ (L′ min, L′max)) If there is an overlapping part, the area matching is successful, and it is determined that the current frame vehicle area corresponds to the traveling vehicle; the area matching success is judged according to Formula 5:

If the current vehicle area is not successfully matched with the previous frame vehicle area, it is determined that the current frame vehicle area corresponds to a new vehicle entering the curve;

Among them, (Qmin, Qmax) represents the range interval formed by the minimum and maximum angle of the vehicle area scanning point, (L′min, L’max) represents the range interval composed of the minimum and maximum distance from the vehicle area scanning point to the center of the circle, S _Q (Qmin, Qmax ) represents the range interval formed by the minimum and maximum angles of the vehicle area scanning point in the current frame, S _L′ (L′min, L’max) represents the range interval composed of the minimum and maximum distance from the current frame vehicle area scanning point to the center of the circle, S′ _Q (Qmin , Qmax indicates the range interval formed by the minimum and maximum angle of the vehicle area scanning point in the previous frame, S'_L'(L'min,L'max indicates the range interval formed by the minimum and maximum distance from the vehicle area scanning point to the center of the circle in the previous frame.

Preferably, the real-time positioning parameters of the vehicle include: the turning radius ρ when the vehicle passes through the curve, the arc length from the front of the vehicle to the stop line when exiting the curve The arc length distance from the rear of the car to the stop line when exiting the bend Body attitude angle θ, vehicle curve line speed ν, angle α between the front of the car and the stop line exiting the bend, and angle β between the rear end and the stop line exiting the bend.

Preferably, the vehicle body attitude angle θ is calculated according to Formula 6:

θ＝arctan(κ) Formula 6;

Among them, κ is the slope corresponding to the fitting line of the scanning points on the side of the vehicle body;

The turning radius ρ when the vehicle passes the curve is calculated according to Formula 7:

Among them, p _b is the inflection point between the side of the car body and the front or rear part of the car, _{ph is the end point of the front of the car, p t is} the starting point of the front of the car, L′(p _b ) is the distance between the inflection point of the side of the car body and the front or rear part of the car to the center of the circle distance, L′(p _h ) is the distance from the end point of the front of the car to the center of the circle, L′(p _t ) is the distance from the start point of the car to the center of the circle, Q(p _h ) is the angle of the end point of the front of the car, Q(p _t ) is The angle of the starting point of the front;

The included angle α between the front of the car and the stop line for exiting the bend is calculated according to Formula 8:

Among them, Q _max = max{ΔQ ₁ ,ΔQ ₂ ,ΔQ ₃ ...ΔQ _n }, which means the maximum value of the angle difference between the front and rear points in all frames of the vehicle passing through the curve, ΔQ _i =|Q(p _h )- Q(p _t )|The angle difference between the front and rear points of the i-th frame, Q ₂ represents the angle of the stop line when exiting the bend;

The arc length distance from the front of the car to the stop line when exiting the bend Calculate according to formula nine:

The included angle β between the rear of the vehicle and the stop line for exiting the bend is calculated according to Formula 10:

The arc length distance from the rear of the car to the stop line at corner exit Calculate according to formula eleven:

The curve line speed ν of the vehicle is calculated according to Formula 12:

Among them, ν(i) represents the curve speed of the vehicle in frame i; Indicates the arc length from the front of the i-th frame to the exit stop line when the vehicle crosses a curve, a fixed value in n∈{1,2,3,4,5}, and f indicates the scanning frequency of the laser scanning unit.

It can be seen from the above technical solution that the present invention provides a curved vehicle positioning device and method, which collects the ranging waveform in the curved area in real time through the laser scanning unit, and the central processing unit performs coordinate conversion, interference elimination and area tracking on the ranging waveform of the current frame. Searching, determining the scanning point position information corresponding to the vehicle area of the current frame, so as to perform area matching between the vehicle area of the current frame and the vehicle area of the previous frame, and determining that the vehicle area of the current frame corresponds to a new vehicle entering a curve or a vehicle traveling in a curve area, And according to the scanning point position information corresponding to the vehicle area in the current frame, obtain and output the real-time positioning parameters of the vehicle. It can be seen that the present invention can realize the real-time positioning of the vehicle in the curve, and the laser scanning unit is used for scanning, and the scanning frequency is high; and the laser ranging is not affected by the ambient light, the ranging accuracy is high, and the positioning accuracy is greatly improved; and it can obtain Rich positioning parameters are used for unmanned vehicles to make turning strategies or to provide speed warnings or reminders for entering and exiting curves during assisted driving.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of existing curve positioning parameters;

Fig. 2 is a schematic structural view of a curved vehicle positioning device in Embodiment 1 of the present invention;

Fig. 3 is a schematic diagram of the laser scanning unit installed at the inner circle center of the curve in Embodiment 1 of the present invention;

Fig. 4 is a schematic diagram of the laser scanning unit installed on the extension line outside the radius of the curve in Embodiment 1 of the present invention;

Fig. 5 is a schematic flowchart of a method for positioning a curved vehicle in Embodiment 2 of the present invention;

Fig. 6 is a schematic diagram of a curve ranging waveform in Embodiment 2 of the present invention;

Fig. 7 is a schematic diagram of coordinate transformation in Embodiment 2 of the present invention;

Fig. 8 is a schematic diagram of the distance from the scanning point to the center of the curve in Embodiment 2 of the present invention;

Fig. 9 is a schematic diagram of curved road surface parameters in Embodiment 2 of the present invention;

Fig. 10 is a schematic diagram of area search in Embodiment 2 of the present invention;

Fig. 11 is a schematic diagram of the attitude angle of the vehicle body in Embodiment 2 of the present invention;

Fig. 12 is a schematic diagram of the installation of the curve vehicle positioning device on the extension line of the curve outer diameter in Embodiment 3 of the present invention;

Fig. 13 is a schematic diagram of a curve ranging waveform in Embodiment 3 of the present invention;

Fig. 14 is a schematic diagram of the current frame vehicle area in a situation in Embodiment 3 of the present invention;

Fig. 15 is a schematic diagram of the vehicle area in the previous frame in Embodiment 3 of the present invention;

Fig. 16 is a schematic diagram of the attitude angle of the vehicle body in a case in Embodiment 3 of the present invention;

Fig. 17 is a schematic diagram of the vehicle area in the current frame under another situation in Embodiment 3 of the present invention;

Fig. 18 is a schematic diagram of the attitude angle of the vehicle body in another case in Embodiment 3 of the present invention;

Fig. 19 is a schematic diagram of the installation of the vehicle positioning device on a curved road at the center of the inner circle of the curved road in Embodiment 4 of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

Fig. 2 is a schematic structural diagram of a curved vehicle positioning device provided in Embodiment 1 of the present invention. As shown in Fig. 2, the device includes: a laser scanning unit 1 and a central processing unit 2;

The laser scanning unit 1 is fixed on the installation pole 2, and is located at the center point inside the curve or the extension line outside the radius of the curve at a preset distance from the lane boundary line, and is used for real-time acquisition of ranging waveforms in the curve area. Wherein, when the laser scanning unit 1 is located at the inner center point of the curve, as shown in FIG. 3 ; when the laser scanning unit 1 is located at a predetermined distance Dis from the extension line outside the radius of the curve to the boundary line of the lane, as shown in FIG. 4 .

The central processing unit 2 is connected to the laser scanning unit 1, and is used to receive the curve area ranging waveform sent by the laser scanning unit 1, and perform coordinate transformation, interference elimination and area search on the current frame ranging waveform , determine the scanning point position information corresponding to the vehicle area in the current frame; perform area matching on the vehicle area in the current frame and the vehicle area in the previous frame, and determine that the vehicle area in the current frame corresponds to a new vehicle entering the curve or a vehicle traveling in the curve area; according to the According to the scanning point position information corresponding to the current frame vehicle area, obtain and output the vehicle real-time positioning parameters.

It can be seen that in this embodiment, the laser scanning unit 1 collects the ranging waveform in the curve area in real time, and the central processing unit 2 performs coordinate conversion, interference elimination and area search on the ranging waveform of the current frame to determine the scanning corresponding to the vehicle area of the current frame. Point position information, to match the vehicle area of the current frame with the vehicle area of the previous frame, determine that the vehicle area of the current frame corresponds to the new vehicle entering the curve or the vehicle traveling in the curve area, and according to the vehicle area corresponding to the current frame Scan point location information, obtain and output vehicle real-time positioning parameters. It can be seen that this embodiment can realize the real-time positioning of the vehicle in the curve, and the laser scanning unit is used for scanning, and the scanning frequency is high; and the laser ranging is not affected by the ambient light, and the ranging accuracy is high, which greatly improves the positioning accuracy; and can Obtain rich positioning parameters for unmanned vehicles to make turning strategies or do speed warnings or reminders for entering and exiting curves during assisted driving.

Further, the device for positioning a vehicle on a curved road in the above embodiment further includes: a power supply unit 4 for supplying power to the laser scanning unit 1 and the central processing unit 2 respectively.

Wherein, when the laser scanning unit 1 is located at a preset distance from the extension line outside the radius of the curve to the lane boundary line, the preset distance Dis is greater than or equal to 2000 mm; the height H of the laser scanning unit from the road surface is greater than or equal to 700 mm and less than or equal to 850mm.

The laser scanning unit 1 uses scanning frequency f and scanning angle resolution Scan parallel to the plane of the road surface. Preferably, the scanning frequency f=50Hz,

The scanning angle range of the laser scanning unit in each scanning period is 0-270°.

It should be noted that the scanning frequency f represents the number of scanning cycles completed by the laser scanning unit (1) within 1s; the scanning angle resolution Indicates the angular interval between scanning points of the laser scanning unit. If the scan angle resolution That is, the angular interval between scanning points is 0.5°.

Example 2

Fig. 5 is a schematic flow chart of a method for positioning a curved vehicle provided in real time 2 of the present invention. As shown in Fig. 5, the method for positioning a curved vehicle includes the following steps:

S1: The laser scanning unit collects the ranging waveform in the curve area in real time.

For example, the ranging waveform in the curve area is shown in FIG. 6 .

S2: The central processing unit receives the ranging waveform in the curve area sent by the laser scanning unit, and performs coordinate conversion, interference elimination and area search on the ranging waveform of the current frame, and determines the position information of the scanning point corresponding to the vehicle area of the current frame;

S3: The central processing unit performs area matching on the vehicle area of the current frame and the vehicle area of the previous frame, and determines that the vehicle area of the current frame corresponds to a new vehicle entering the curve or a vehicle traveling in the curve area;

S4: The central processing unit obtains and outputs real-time vehicle positioning parameters according to the scanning point position information corresponding to the vehicle area in the current frame.

Among them, the real-time positioning parameters of the vehicle include: the turning radius ρ when the vehicle passes through the curve, the arc length from the front of the vehicle to the stop line when exiting the curve The arc length distance from the rear of the car to the stop line when exiting the bend Body attitude angle θ, vehicle curve speed ν, angle α between the front of the car and the stop line exiting the bend, and angle β between the rear end and the stop line exiting the bend, etc.

Further, in an optional embodiment of the present invention, the curve vehicle positioning method further includes the following steps not shown in FIG. 5:

S5: The central processing unit tracks the new vehicle entering the curve in real time, so as to remove the vehicle when the new vehicle entering the curve leaves the curve area.

Specifically, the central processing unit tracks the vehicle entering the curve in real time, and when the vehicle leaves the curve area, the central processing unit knows the vehicle, even if the laser scanning unit can still scan the vehicle, the central processing unit will The vehicle is not located and tracked.

Specifically, the coordinate transformation in step S2 specifically includes:

According to the formula (1), the coordinate conversion of the current frame ranging waveform is carried out:

Among them, i is the serial number of the scanning point, L(i) is the distance from the scanning point i to the center point of the laser scanning unit, n ₀ is the serial number of the emitting point where the emitted light coincides with the ox axis in the laser scanning unit, is the scanning angular resolution of the laser scanning unit, x(i) is the abscissa of scanning point i in the oxy rectangular coordinate system, and y(i) is the vertical coordinate of scanning point i in the oxy rectangular coordinate system.

It should be noted that, as shown in Figure 7, the center point of the laser scanning unit is the coordinate system point o, the side of the laser scanning unit is the coordinate axis oy, and the vertical line passing through the oy axis is the ox axis to establish a rectangular coordinate system oxy. The emission ray at which scan point _n0 is located coincides with the ox axis. For any scanning point i, the angle between the emitted light and the ox axis is Then, according to the triangular geometric relationship, the distance L(i) from the scanning point i to the center point of the laser scanning unit satisfies the above-mentioned coordinate conversion relationship.

Specifically, the interference elimination in step S2 specifically includes the following steps:

Step 1: Calculate the distance L′(i) from scanning point i to the inner circle center of the curve according to the formula (2):

Wherein, when the laser scanning unit is at the center of the inner circle of the curve, the center o of the laser scanning unit coincides with the center point o’ of the inner circle of the curve, then the distance value L(i)=L’(i ).

When the laser scanning unit is on the extension line outside the radius of the curve, as shown in Figure 8, OM=Dis, O'M=R ₂ , then according to the scanning point i, the center point O of the laser scanning unit and the center o' inside the curve The above calculation formula can be deduced from the geometric relationship between them.

Step 2: Calculate the angle Q(i) between the scanning point i and the line where the center of the inner circle of the curve is located and the radius of the ox axis according to the formula (3):

$\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arcsin</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, the center point of the laser scanning unit is the coordinate system circle point o, the side of the laser scanning unit is the coordinate axis oy, and the vertical line passing through the o point of the y axis is the ox axis;

Step 3: According to Q(i) and L'(i), use formula (4) to exclude the scanning points that are not in the curve and not in the range of the curve lane:

Among them, as shown in Figure ₉ , R1 is the radius of the arc section of the boundary near the center of the curve, _R2 is the radius of the arc section of the boundary far from the center of the curve, and Q1 is the line between the starting point _of the curve and the center of the inner circle of the curve. The included angle between the radii of the axis, Q ₂ is the included angle between the end point of the curve and the line where the center of the inner circle of the curve is located and the radius of the ox axis.

Specifically, the area search in step S2 specifically includes:

Determine the boundary point corresponding to the current frame vehicle area and the point to which the vehicle area belongs according to the scanning point coordinates after interference elimination, specifically determine the boundary point of the current frame vehicle area and the point to which the vehicle area belongs according to the following method:

If x(i-1)=0 and x(i)>0, then it is determined that scanning point i is the initial boundary point of the vehicle area;

If x(i-1)>0 and x(i)>0, it is determined that the scan point i belongs to the area where the scan point i-1 is located;

If x(i)>0 and x(i+1)=0, it is determined that scanning point i is the end boundary point of the vehicle area.

For example, as shown in Figure 10, point 3 satisfies x(2)=0 and x(3)>0, then point 3 is the initial boundary point of the area; point 4 satisfies x(3)>0 and x(4) >0, then point 4 and point 3 belong to the same area; similarly, points 5, 6 and 7 and point 3 all belong to the same area; point 8 satisfies x(8)>0 and x(9)=0, then point 8 is The region ends at the boundary point. It can be found that points 3, 4, 5, 6, 7, and 8 belong to the same area.

Specifically, in step S3, the area matching of the current frame vehicle area and the previous frame vehicle area, and determining that the current frame vehicle area corresponds to a new vehicle entering a curve or a vehicle traveling in a curve area, specifically includes:

According to the boundary range relationship between the vehicle area in the current frame and the vehicle area in the previous frame, identify new vehicles entering the curve or track vehicles traveling in the curve area:

If the current frame vehicle area (S _Q (Qmin, Qmax), S _L′ (L′min, L′max)) and the previous frame vehicle area (S′ _Q (Qmin, Qmax), S′ _L′ (L′ min, L'max)) If there is an overlapping part, the area matching is successful, and it is determined that the current frame vehicle area corresponds to the traveling vehicle; the area matching success is judged according to formula (5):

If the current vehicle area is not successfully matched with the previous frame vehicle area, it is determined that the current frame vehicle area corresponds to a new vehicle entering the curve;

Among them, (Qmin, Qmax) represents the range interval formed by the minimum and maximum angle of the vehicle area scanning point, (L′min, L’max) represents the range interval composed of the minimum and maximum distance from the vehicle area scanning point to the center of the circle, S _Q (Qmin, Qmax ) represents the range interval formed by the minimum and maximum angles of the vehicle area scanning point in the current frame, S _L′ (L′min, L’max) represents the range interval composed of the minimum and maximum distance from the current frame vehicle area scanning point to the center of the circle, S′ _Q (Qmin , Qmax indicates the range interval formed by the minimum and maximum angle of the vehicle area scanning point in the previous frame, S'_L'(L'min,L'max indicates the range interval formed by the minimum and maximum distance from the vehicle area scanning point to the center of the circle in the previous frame.

Further, as shown in Figure 1, the real-time positioning parameters of the vehicle include: the turning radius θ when the vehicle passes through the curve, the arc length from the front of the vehicle to the stop line when exiting the curve The arc length distance from the rear of the car to the stop line when exiting the bend Body attitude angle θ, vehicle curve line speed ν, angle α between the front of the car and the stop line exiting the bend, and angle β between the rear end and the stop line exiting the bend.

Wherein, the body attitude angle θ is calculated according to formula (6):

θ=arctan(κ) (6)

Among them, κ is the slope corresponding to the fitting line of the scanning points on the side of the vehicle body.

For example, when calculating the attitude angle of the vehicle body, as shown in Figure 11, the inflection point p _b between the side of the vehicle body and the front or rear part of the vehicle, the front _{ph and the rear p t are} first found in the vehicle area, and then by fitting the body The straight line where the scanning points are located in the side segment p _t p _b obtains the slope of the fitted straight line κ=-0.460, then θ=arctan(-0.460)=-24.7°.

Wherein, the turning radius ρ of the vehicle passing through the curve is calculated according to formula (7):

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>\\ \frac{{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</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">\; 7</span>}<span\; class="notranslate">\; )</span>$

Among them, p _b is the inflection point between the side of the car body and the front or rear part of the car, _{ph is the end point of the front of the car, p t is} the starting point of the front of the car, L′(p _b ) is the distance between the inflection point of the side of the car body and the front or rear part of the car to the center of the circle distance, L′(p _h ) is the distance from the end point of the front of the car to the center of the circle, L′(p _t ) is the distance from the start point of the car to the center of the circle, Q(p _h ) is the angle of the end point of the front of the car, Q(p _t ) is The angle of the starting point of the front;

The included angle α between the front of the car and the stop line for exiting the bend is calculated according to the formula (8):

$\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</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">\; 8</span>}<span\; class="notranslate">\; )</span>$

Among them, Q _max = max{ΔQ ₁ ,ΔQ ₂ ,ΔQ ₃ ...ΔQ _n }, which means the maximum value of the angle difference between the front and rear points in all frames of the vehicle passing through the curve, ΔQ _i =|Q(p _h )- Q(p _t )|The angle difference between the front and rear points of the i-th frame, Q ₂ represents the angle of the stop line when exiting the bend;

Wherein, the arc length distance from the front of the vehicle to the stop line for exiting the bend Calculate according to formula (9):

The included angle β between the rear of the vehicle and the stop line for exiting the bend is calculated according to the formula (10):

$\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</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">\; 10</span>}<span\; class="notranslate">\; )</span>$

The arc length distance from the rear of the car to the stop line at corner exit Calculate according to formula (11):

The curve line speed ν of the vehicle is calculated according to Formula 12:

Among them, ν(i) represents the curve speed of the vehicle in frame i; Indicates the arc length from the front of the i-th frame to the exit stop line when the vehicle crosses a curve, a fixed value in n∈{1,2,3,4,5}, and f indicates the scanning frequency of the laser scanning unit.

It can be seen that in this embodiment, the laser scanning unit is used for scanning, and its scanning frequency is extremely high, at least one positioning can be made within 20ms, so real-time positioning of the curve can be realized; laser ranging is not affected by ambient light, etc. The distance accuracy is extremely high, which greatly improves the positioning accuracy. In addition, the device and method are based on the actual curve, and realize the positioning in the curve area, which can avoid intermediate errors; the positioning parameters in this embodiment include the vehicle's speed, pose, Important parameters such as the distance from the stop line when exiting the curve, and the turning radius can be used for unmanned vehicles to make a turning strategy or to provide speed warnings or reminders for entering and exiting curves during assisted driving.

Example 3

In this embodiment, as shown in FIG. 12 , the curve vehicle positioning device is installed at a preset distance from the extension line outside the curve radius to the lane boundary line. Among them, the radius of the arc segment near the center of the curve R ₁ = 10000mm, the radius of the arc segment far from the center of the curve R ₂ = 14000mm, the gap between the starting point of the curve and the line where the center of the curve is located inside the curve and the radius of the ox axis The angle Q ₁ =-45°, the included angle Q ₂ =45° between the end point of the curve and the straight line where the center of the inner circle of the curve is located and the radius of the ox axis.

Among them, the curved vehicle positioning device includes: a laser scanning unit 1, a central processing unit 2, a mounting pole 3 and a power supply unit 4. The laser scanning unit 1 is fixed on the mounting pole 3, and is located outside the radius of the curve. At the distance of Dis=2000mm from the boundary line, the height from the road surface is H=700mm, with the scanning frequency f=50HZ and the scanning angle resolution Do a 0-180° scan parallel to the plane where the road surface is located, and the scanning point n ₀ =180 emits light that coincides with the ox axis, and is used for real-time acquisition of body distance measurement waveforms when the vehicle passes through the curve area.

Wherein, the central processing unit 2 is connected with the laser scanning unit 1, and is used for receiving and processing the ranging waveform collected by the laser scanning unit 1, and processing and outputting real-time positioning parameters of the vehicle.

When the vehicle passes through the curve where the device is installed, the following curve vehicle positioning method provided by this embodiment is used for real-time detection and positioning of the vehicle:

(1) The laser scanning unit collects the ranging waveform in the curve area in real time;

(2) The central processing unit performs coordinate transformation, interference elimination and area search on the ranging waveform of the current frame;

(5) The central processing unit realizes region matching according to the region search result of the current frame and the region search result of the previous frame, and distinguishes new vehicles or tracks vehicles;

(6) The central processing unit calculates the real-time vehicle positioning parameters according to the area matching results and outputs the real-time positioning results;

(7) The central processing unit distinguishes the vehicle leaving the curve according to the tracking result of the new vehicle, and clears the leaving vehicle.

Wherein, the coordinate conversion, interference elimination, area search and area matching are the same as those in Embodiment 2, and will not be repeated here.

When the vehicle passes through the curve, there will be two situations where the front of the vehicle does not cross the 0-point line and the front of the vehicle passes the 0-point line.

During a detection and positioning process, the encountered situation 1 vehicle did not pass the 0-point line, and the ranging waveform of the curve area collected by the laser scanning unit in real time is shown in Figure 13.

After the central processing unit coordinate conversion, interference elimination and area search, the obtained vehicle area is shown in Figure 14.

The central processing unit compares the area search results of the current frame with the area search results of the previous frame (as shown in Figure 15), and finds that there is an overlap between the two vehicle areas, and obtains that the vehicle area of the current frame matches the vehicle area of the previous frame successfully, and judges the current frame area. The vehicle area is the moving vehicle, which realizes the tracking of the moving vehicle.

At the same time, as shown in Figure 16, by performing straight line fitting on the scanning points of the side part of the vehicle body, the slope of the fitted line κ=-0.396 is obtained, and the calculated real-time body attitude angle θ=arctan(-0.396)=-21.6 °;

At this time, since Q(p _h )=-4.63°<0, the turning radius ρ when passing the curve:

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 12338</span>}\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ;</span>$

The angle α between the front of the vehicle and the stop line is:

α=|Q(p _h )-Q ₂ |=|-4.63°-45°|=49.63°;

The arc length from the front of the car to the exit stop line for:

The angle β between the rear of the vehicle and the stop line is:

β=|Q(p _h )-Q _max -Q ₂ |=|-4.63°-16°-45°|=65.63°;

The arc length from the rear of the car mentioned above to the exit stop line for:

The vehicle curve speed ν is:

Situation 2: The front of the vehicle passes the 0-point line, and the vehicle area after the central processing unit performs coordinate conversion, interference elimination, area search, and area matching is shown in Figure 17.

By performing straight line fitting on the scanning points of the side part of the vehicle body, as shown in Figure 18, the slope of the fitted straight line κ=0.230 is obtained, then the calculated real-time body attitude angle θ=arctan(0.230)=12.95°;

At this time, since Q(p _h )=21.17°>0, the turning radius ρ when passing the curve:

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 12041.83</span>}\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ;</span>$

The angle α between the front of the vehicle and the stop line is:

α=|Q(p _t )+Q _max -Q ₂ |=|4.74°+16°-45°|=24.26°;

The arc length from the front of the car to the exit stop line for:

The angle β between the rear of the vehicle and the stop line is:

β=|Q(p _t )-Q ₂ |=|4.74°-45°|=40.26°;

The arc length from the rear of the car mentioned above to the exit stop line for:

The vehicle curve speed ν is:

Example 4

In this embodiment, as shown in FIG. 19 , the curve vehicle positioning device is installed at the inner circle center point of the curve. Among them, the radius of the arc segment near the center of the curve R ₁ =6000mm, the radius of the arc segment far from the center of the curve R ₂ =10000mm, the gap between the starting point of the curve and the line where the center of the curve is located inside the curve and the radius of the ox axis The angle Q ₁ =-45°, the included angle Q ₂ =45° between the end point of the curve and the straight line where the center of the inner circle of the curve is located and the radius of the ox axis.

Among them, the curved vehicle positioning device includes: a laser scanning unit 1, a central processing unit 2, a mounting pole 3 and a power supply unit 4. The laser scanning unit 1 is fixed on the mounting pole 3 and is located at the center of the inner circle of the curve. The height is H=700mm, with scanning frequency f=50HZ and scanning angle resolution 0-180° scanning is performed parallel to the plane where the road surface is located. The scanning point n ₀ =180 emits light that coincides with the ox axis, and is used for real-time acquisition of body distance measurement waveforms when the vehicle passes through a curve.

Wherein, the central processing unit 2 is connected with the laser scanning unit 1, and is used for receiving and processing the ranging waveform collected by the laser scanning unit 1, and processing and outputting real-time positioning parameters of the vehicle.

When the vehicle passes through the curve where the device is installed, the following curve vehicle positioning method provided by this embodiment is used for real-time detection and positioning of the vehicle:

(1) The laser scanning unit collects the ranging waveform in the curve area in real time;

(2) The central processing unit performs coordinate transformation, interference elimination and area search on the ranging waveform of the current frame;

(5) The central processing unit realizes region matching according to the region search result of the current frame and the region search result of the previous frame, and distinguishes new vehicles or tracks vehicles;

(6) The central processing unit calculates the real-time vehicle positioning parameters according to the area matching results and outputs the real-time positioning results;

(7) The central processing unit distinguishes the vehicle leaving the curve according to the tracking result of the new vehicle, and clears the leaving vehicle.

Wherein, the coordinate conversion, interference elimination, area search and area matching are the same as those in Embodiment 2, and will not be repeated here.

The biggest difference between Embodiment 4 and Embodiment 3 is that the installation position of the laser scanning unit is installed at the center of the inner circle of the curve, and at the same time, the distance value L'(i) between the scanning point i and the inner circle center of the curve is different when calculating the interference , the other methods are the same and will not be repeated here.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by program instructions and related hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

It should also be noted that in this article, relational terms such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations Any such actual relationship or order exists between. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be described in the foregoing embodiments Modifications are made to the recorded technical solutions, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A curved vehicle positioning device, characterized in that the device comprises: a laser scanning unit and a central processing unit; The laser scanning unit is fixed on the installation pole, and is located at the center point inside the curve or the extension line outside the radius of the curve at a preset distance from the lane boundary line, and is used for real-time acquisition of ranging waveforms in the curve area; The central processing unit is connected with the laser scanning unit, and is used to receive the ranging waveform in the curve area sent by the laser scanning unit, and perform coordinate transformation, interference elimination and area search on the ranging waveform of the current frame to determine the current Scanning point position information corresponding to the frame vehicle area; area matching is performed between the current frame vehicle area and the previous frame vehicle area, and it is determined that the current frame vehicle area corresponds to a new vehicle entering the curve or a vehicle traveling in the curve area; according to the current frame The location information of the scanning point corresponding to the vehicle area, obtains and outputs the real-time positioning parameters of the vehicle. 2. The device according to claim 1, wherein when the laser scanning unit is located at a preset distance from the extension line outside the radius of the curve to the boundary line of the lane, the preset distance is greater than or equal to 2000mm; The height of the laser scanning unit from the road surface is greater than or equal to 700mm and less than or equal to 850mm; The laser scanning unit uses scanning frequency f and scanning angle resolution Scan parallel to the plane of the road surface; The scanning angle range of the laser scanning unit in each scanning period is 0-270°. 3. A method for positioning a curved vehicle, characterized in that the method comprises: The laser scanning unit collects the ranging waveform in the curve area in real time; The central processing unit receives the ranging waveform in the curve area sent by the laser scanning unit, and performs coordinate conversion, interference elimination and area search on the ranging waveform of the current frame to determine the scanning point position information corresponding to the vehicle area of the current frame; The central processing unit performs area matching on the vehicle area of the current frame and the vehicle area of the previous frame, and determines that the vehicle area of the current frame corresponds to a new vehicle entering the curve or a vehicle traveling in the curve area; The central processing unit obtains and outputs real-time vehicle positioning parameters according to the scanning point position information corresponding to the vehicle area in the current frame. 4. method according to claim 3, is characterized in that, described method also comprises: The central processing unit tracks the new vehicle entering the curve in real time, so as to remove the vehicle when the new vehicle entering the curve leaves the curve area. 5. The method according to claim 3, wherein the coordinate transformation comprises: According to the formula, coordinate conversion is performed on the ranging waveform of the current frame: Among them, i is the serial number of the scanning point, L(i) is the distance from the scanning point i to the center point of the laser scanning unit, n ₀ is the serial number of the emitting point where the emitted light coincides with the ox axis in the laser scanning unit, is the scanning angular resolution of the laser scanning unit, x(i) is the abscissa of scanning point i in the oxy rectangular coordinate system, and y(i) is the vertical coordinate of scanning point i in the oxy rectangular coordinate system. 6. The method according to claim 5, wherein the interference elimination comprises: Step 1: Calculate the distance L′(i) from scanning point i to the center of the inner circle of the curve according to formula 2: Step 2: Calculate the angle Q(i) between the scan point i and the line where the center of the circle inside the curve is located and the radius of the ox axis according to formula 3: Among them, the center point of the laser scanning unit is the coordinate system circle point o, the side of the laser scanning unit is the coordinate axis oy, and the vertical line passing through the o point of the y axis is the ox axis; Step 3: According to Q(i) and L'(i), use formula 4 to exclude the scanning points that are not in the curve and not in the range of the curve lane: Among them, R ₁ is the radius of the arc segment near the center of the curve, R ₂ is the radius of the arc segment far from the center of the curve, and Q ₁ is the distance between the starting point of the curve and the line where the center of the inner circle of the curve is located and the radius of the ox axis. Included angle, Q ₂ is the angle between the end point of the curve and the straight line where the inner center of the curve is located and the radius of the ox axis. 7. The method according to claim 6, wherein the area search comprises: Determine the boundary point corresponding to the current frame vehicle area and the point to which the vehicle area belongs according to the scan point coordinates after interference elimination: If x(i-1)=0 and x(i)>0, then it is determined that scanning point i is the initial boundary point of the vehicle area; If x(i-1)>0 and x(i)>0, it is determined that the scan point i belongs to the area where the scan point i-1 is located; If x(i)>0 and x(i+1)=0, it is determined that scanning point i is the end boundary point of the vehicle area. 8. The method according to claim 3, wherein the vehicle area in the current frame is matched with the vehicle area in the previous frame, and it is determined that the vehicle area in the current frame corresponds to a new vehicle entering a curve or is traveling in a curve area vehicles, including: According to the boundary range relationship between the vehicle area in the current frame and the vehicle area in the previous frame, identify new vehicles entering the curve or track vehicles traveling in the curve area: If the current frame vehicle area (S _Q (Qmin, Qmax), S _L′ (L′min, L′max)) and the previous frame vehicle area (S′ _Q (Qmin, Qmax), S′ _L′ (L′ min, L′max)) If there is an overlapping part, the area matching is successful, and it is determined that the current frame vehicle area corresponds to the traveling vehicle; the area matching success is judged according to Formula 5: If the current vehicle area is not successfully matched with the previous frame vehicle area, it is determined that the current frame vehicle area corresponds to a new vehicle entering the curve; Among them, (Qmin, Qmax) represents the range interval formed by the minimum and maximum angle of the vehicle area scanning point, (L′min, L’max) represents the range interval composed of the minimum and maximum distance from the vehicle area scanning point to the center of the circle, S _Q (Qmin, Qmax ) represents the range interval formed by the minimum and maximum angles of the vehicle area scanning point in the current frame, S _L′ (L′min, L’max) represents the range interval composed of the minimum and maximum distance from the current frame vehicle area scanning point to the center of the circle, S′ _Q (Qmin , Qmax indicates the range interval formed by the minimum and maximum angle of the vehicle area scanning point in the previous frame, S'_L'(L'min,L'max indicates the range interval formed by the minimum and maximum distance from the vehicle area scanning point to the center of the circle in the previous frame. 9. The method according to claim 3, wherein the real-time positioning parameters of the vehicle include: the turning radius ρ when the vehicle passes through the curve, the arc length from the front of the vehicle to the stop line when exiting the curve The arc length distance from the rear of the car to the stop line when exiting the bend Body attitude angle θ, vehicle curve line speed ν, angle α between the front of the car and the stop line exiting the bend, and angle β between the rear end and the stop line exiting the bend. 10. The method of claim 9, wherein, The body attitude angle θ is calculated according to formula six: θ=arctan (κ) formula six; Among them, κ is the slope corresponding to the fitting line of the scanning points on the side of the vehicle body; The turning radius ρ when the vehicle passes the curve is calculated according to Formula 7: Among them, p _b is the inflection point between the side of the car body and the front or rear part of the car, _{ph is the end point of the front of the car, p t is} the starting point of the front of the car, L′(p _b ) is the distance between the inflection point of the side of the car body and the front or rear part of the car to the center of the circle distance, L′(p _h ) is the distance from the end point of the front of the car to the center of the circle, L′(p _t ) is the distance from the start point of the car to the center of the circle, Q(p _h ) is the angle of the end point of the front of the car, Q(p _t ) is The angle of the starting point of the front; The included angle α between the front of the car and the stop line for exiting the bend is calculated according to Formula 8: Among them, Q _max = max{ΔQ ₁ ,ΔQ ₂ ,ΔQ ₃ ...ΔQ _n }, which means the maximum value of the angle difference between the front and rear points in all frames of the vehicle passing through the curve, ΔQ _i =|Q(p _h )- Q(p _t )|The angle difference between the front and rear points of the i-th frame, Q ₂ represents the angle of the stop line when exiting the curve; The arc length distance from the front of the car to the stop line when exiting the bend Calculate according to formula nine: The included angle β between the rear of the vehicle and the stop line for exiting the bend is calculated according to Formula 10: The arc length distance from the rear of the car to the stop line at corner exit Calculate according to formula eleven: The curve line speed ν of the vehicle is calculated according to Formula 12: Among them, ν(i) represents the curve speed of the vehicle in frame i; Indicates the arc length from the front of the i-th frame to the exit stop line when the vehicle crosses a curve, a fixed value in n∈{1,2,3,4,5}, and f indicates the scanning frequency of the laser scanning unit.