CN104820205A - Vehicle positioning method based on electronic license plate, and system thereof - Google Patents

Abstract

The invention provides a vehicle positioning method based on an electronic license plate, which comprises the steps of transmitting a waking-up signal to the electronic license plate of the vehicle through an electronic license plate positioning device, so that the electronic license plate feeds a microwave signal back to the positioning device according to the waking-up signal; when the positioning device receives the microwave signal, analyzing the microwave signal for acquiring the time difference between the microwave signals which are received by at least two antennae in the positioning device, the power strengths of the microwave signals and length and width information of the vehicle; according to the time difference and the power strengths, acquiring the position information of the electronic license plate of the vehicle; and according to the length and width information of the vehicle and the position information of the electronic label, acquiring the position information and movement track of the vehicle contour. The vehicle positioning method has functions of reducing number of receiving antennae required in the positioning device, reducing hardware cost and furthermore improving positioning precision.

Description

A kind of vehicle positioning method based on electronic license plate and system

Technical field

The present invention relates to vehicle positioning technology field, particularly relate to a kind of vehicle positioning method based on electronic license plate and system.

Background technology

Flourish along with communications and transportation cause, the electronic license plate based on radio-frequency (RF) identification (Radio FrequencyIdentification, RFID) technology is widely used in field of traffic.An one important application is exactly the location of electronic license plate.

At present for the location of electronic license plate, what generally adopt is the mistiming algorithm based on receiving antenna or the signal amplitude algorithm based on receiving antenna.Wherein based on the mistiming location algorithm required for the antenna number of installing be at least the basic positioning requirements of 3 guarantees, selectable degree of freedom is not high, and the degree of accuracy of location is not high; And based on the location algorithm of power level when selecting antenna number to be two, the coordinate of horizontal direction can only be oriented, and the location of two-dimensional coordinate cannot be completed, when selecting 3 antennas to position, can realize the location of two-dimensional coordinate reluctantly, but same degree of accuracy is not high.Owing to adopting the antenna number required for the two-dimensional coordinate positioning system of these two kinds of algorithms to be at least 3, cause again a whole set of positioning system cost relatively high, selectable degree of freedom is less, greatly limit the development of electronic license plate location technology.

And, current location technology all general for be the location of the coordinate points of electronic license plate, actual application is then the location of the vehicle ' s contour based on electronic license plate, and the position contributing to on-highway motor vehicle weighing apparatus is determined, but, seldom relate to the location technology of vehicle ' s contour in the market.

Summary of the invention

For the defect of prior art, the invention provides a kind of vehicle positioning method based on electronic license plate and system, the number of required receiving antenna in locating device can be reduced, reduce hardware cost, and improve positioning precision simultaneously.

First aspect, the invention provides a kind of vehicle positioning method based on electronic license plate, the method comprises:

By electronic license plate locating device timed sending wake-up signal to the electronic license plate of vehicle, feed back microwave signal to described locating device to make described electronic license plate according to described wake-up signal;

When described locating device receives described microwave signal, described microwave signal is resolved, to obtain in locating device the length and width information that at least two antennas receive mistiming of described microwave signal, power level and described vehicle;

According to described mistiming and power level, obtain the positional information of the electronic license plate of described vehicle;

According to the length and width information of described vehicle and the positional information of described electronic license plate, obtain positional information and the movement locus of described vehicle ' s contour.

Preferably, described by electronic license plate locating device timed sending wake-up signal to the electronic license plate of vehicle step before, the method also comprises:

The system time of vehicle electric license plate positioning device each in scanning area is carried out synchronously.

Preferably, described according to described mistiming and power level, obtain the positional information of the electronic license plate of described vehicle, comprising:

When described electronic license plate locating device comprises 2 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂be respectively the power level that two antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, and T is the mistiming that two antennas receive microwave signal, C is the light velocity, and Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

Preferably, described according to described mistiming and power level, obtain the positional information of the electronic license plate of described vehicle, comprising:

When described electronic license plate locating device comprises 3 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_3=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(2m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T_1*C$

$\sqrt{x^2+y^2}-\sqrt{{(2m-x)}^2+y^2}=T_2*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂, RSSI ₃be respectively the power level that three antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, T ₁for antenna 1 and antenna 2 receive the mistiming of microwave signal, T ₂for antenna 1 and antenna 3 receive the mistiming of radiofrequency signal, C is the light velocity.Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), and Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

Preferably, described according to the length and width information of described vehicle and the positional information of described electronic license plate, obtain positional information and the movement locus of described vehicle ' s contour, comprising:

According to the coordinate figure (x, y) of electronic license plate, and the length and width information of described vehicle, 4 position coordinateses obtaining vehicle ' s contour are respectively: wherein, p, q are respectively the length of described vehicle and wide;

By the positional information of vehicle ' s contour described in timing acquisition, obtain the movement locus of described vehicle.

Second aspect, the invention provides a kind of Vehicle positioning system based on electronic license plate, and this system comprises:

Transmitting element, for passing through the electronic license plate of electronic license plate locating device timed sending wake-up signal to vehicle, to make described electronic license plate according to described wake-up signal feedback microwave signal to described locating device;

Receiving element, for receiving described microwave signal;

Resolution unit, for resolving described microwave signal, to obtain in locating device the length and width information that at least two antennas receive mistiming of described microwave signal, power level and described vehicle;

Location information acquiring unit, for according to described mistiming and power level, obtains the positional information of the electronic license plate of described vehicle;

Vehicle locating unit, for according to the length and width information of described vehicle and the positional information of described electronic license plate, obtains positional information and the movement locus of described vehicle ' s contour.

Preferably, this system also comprises:

Time synchronized unit, for carrying out synchronously the system time of vehicle electric license plate positioning device each in scanning area.

Preferably, described location information acquiring unit, specifically for:

When described electronic license plate locating device comprises 2 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂be respectively the power level that two antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, and T is the mistiming that two antennas receive microwave signal, C is the light velocity, and Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

Preferably, described location information acquiring unit, specifically for:

When described electronic license plate locating device comprises 3 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_3=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(2m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T_1*C$

$\sqrt{x^2+y^2}-\sqrt{{(2m-x)}^2+y^2}=T_2*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂, RSSI ₃be respectively the power level that three antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, T ₁for antenna 1 and antenna 2 receive the mistiming of microwave signal, T ₂for antenna 1 and antenna 3 receive the mistiming of radiofrequency signal, C is the light velocity.Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), and Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

Preferably, described vehicle locating unit, specifically for:

According to the coordinate figure (x, y) of electronic license plate, and the length and width information of described vehicle, 4 position coordinateses obtaining vehicle ' s contour are respectively: wherein, p, q are respectively the length of described vehicle and wide;

By the positional information of vehicle ' s contour described in timing acquisition, obtain the movement locus of described vehicle.

As shown from the above technical solution, the invention provides a kind of vehicle positioning method based on electronic license plate and system, according to the mistiming of radio signal transmission to different antennae and the size of power level, hybrid algorithm based on mistiming and power level calculates the two-dimensional position information of electronic license plate, and then obtain the profile information of vehicle, the number of required receiving antenna in locating device can be reduced, reduce hardware cost, and improve positioning precision simultaneously.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these figure.

Fig. 1 is the schematic flow sheet of a kind of vehicle positioning method based on electronic license plate that one embodiment of the invention provides;

Fig. 2 is the relative position schematic diagram of two antennas providing of another embodiment of the present invention and electronic license plate;

Fig. 3 is the relative position schematic diagram of three antennas providing of another embodiment of the present invention and electronic license plate;

Fig. 4 is the schematic diagram of the electronic license plate that provides of another embodiment of the present invention and vehicle ' s contour positional information;

Fig. 5 is the structural representation of a kind of Vehicular system based on electronic license plate that one embodiment of the invention provides.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

As shown in Figure 1, be the schematic flow sheet of a kind of vehicle positioning method based on electronic license plate that one embodiment of the invention provides, the method comprises the steps:

S1: by electronic license plate locating device timed sending wake-up signal to the electronic license plate of vehicle, feed back microwave signal to described locating device to make described electronic license plate according to described wake-up signal;

Particularly, send wake-up signal by the antenna of electronic license plate locating device, after electronic license plate receives wake-up signal, feedback microwave signal is to the antenna of locating device.

S2: when described locating device receives described microwave signal, resolve described microwave signal, to obtain in locating device the length and width information that at least two antennas receive mistiming of described microwave signal, power level and described vehicle;

Specifically, the electronic license plate locating device in the present embodiment comprises at least two antennas.Often increase an antenna, positioning precision can be improved further.After locating device receives described microwave signal, record microwave signal reaches the system time of each antenna, thus calculates the mistiming; And obtain the power level size that microwave signal reaches each antenna; Finally microwave signal is resolved, obtain vehicle length and width information.

S3: according to described mistiming and power level, obtains the positional information of the electronic license plate of described vehicle;

Particularly, the positional information of electronic license plate is calculated in the present embodiment based on the mixing computing method of mistiming and power level, i.e. coordinate information.

S4: according to the length and width information of described vehicle and the positional information of described electronic license plate, obtain positional information and the movement locus of described vehicle ' s contour.

In the present embodiment, before step S1, the method also comprises the steps:

The system time of vehicle electric license plate positioning device each in scanning area is carried out synchronously.Namely the system time of antenna each in locating device is carried out synchronously, so that the mistiming of subsequent calculations is accurate.

For example, when the antenna number in locating device is 2, then step S3 specifically comprises:

As shown in Figure 2, when described electronic license plate locating device comprises 2 antennas (antenna 1, antenna 2), then:

RSSI ₁＝P+Gr+Gt-Lc-Lbf ₁(1)

RSSI ₂＝P+Gr+Gt-Lc-Lbf ₂(2)

Wherein, RSSI ₁for the power level that antenna 1 receives, RSSI ₂for the power level that antenna 2 receives; P is the emissive power of electronic license plate; Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), and Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant; Lbf ₁the microwave launched for electronic license plate to the space loss of antenna 1, Lbf ₂the microwave launched for electronic license plate is to the space loss of antenna 2.

Wherein:

${\mathrm{Lbf}}_1=10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4{\mathrm{\πr}}_{N1}\right)}^2}---\left(3\right)$

${\mathrm{Lbf}}_2=10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4{\mathrm{\πr}}_{N2}\right)}^2}---\left(4\right)$

Wherein, λ is the wavelength of transmitted wave, r _n1for electronic license plate is to the distance of antenna 1 r _n2for electronic license plate is to the distance of antenna 2

Then Lbf ₁, Lbf ₂bring above-mentioned formula (1) and (2) respectively into, obtain:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-\mathrm{Lc}---\left(5\right)$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc---\left(6\right)$

Further, receive the mistiming T of microwave signal according to two antennas, have following formula:

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T*C---\left(7\right)$

Wherein, m is the horizontal range of emitting antenna, and T is the mistiming that two antennas receive microwave signal, and C is the light velocity.

Aggregative formula (5), (6) and (7), obtain system of equations:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T*C$

By Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate.

As can be seen here, the minimum number of receiving antenna can be reduced by the method, namely 2 antennas are decreased to, ensure that on-the-spot minimum needs to realize the accurate location to power vehicle and tracing of the movement when two receiving antennas, reduces hardware cost under the prerequisite ensureing degree of accuracy.

For example, when the antenna number in locating device is 3, then step S3 specifically comprises:

As shown in Figure 3, when described electronic license plate locating device comprises 3 antennas (antenna 1, antenna 2 and antenna 3):

RSSI ₁＝P+Gr+Gt-Lc-Lbf ₁(8)

RSSI ₂＝P+Gr+Gt-Lc-Lbf ₂(9)

RSSI ₃＝P+Gr+Gt-Lc-Lbf ₃(10)

Wherein, RSSI ₁for the power level that antenna 1 receives, RSSI ₂for the power level that antenna 2 receives, RSSI ₃for the power level that antenna 3 receives; P is the emissive power of electronic license plate; Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), and Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant; Lbf ₁the microwave launched for electronic license plate to the space loss of antenna 1, Lbf ₂the microwave launched for electronic license plate to the space loss of antenna 2, Lbf ₃the microwave launched for electronic license plate is to the space loss of antenna 3.

Wherein:

${\mathrm{Lbf}}_1=10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4{\mathrm{\πr}}_{N1}\right)}^2}---\left(11\right)$

${\mathrm{Lbf}}_2=10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4{\mathrm{\πr}}_{N2}\right)}^2}---\left(12\right)$

${\mathrm{Lbf}}_3=10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4{\mathrm{\πr}}_{N3}\right)}^2}---\left(13\right)$

Wherein, λ is the wavelength of transmitted wave, r _n1for electronic license plate is to the distance of antenna 1 r _n2for electronic license plate is to the distance of antenna 2 r _n3for electronic license plate is to the distance of antenna 3

By Lbf ₁, Lbf ₂, Lbf ₃bring above-mentioned formula (8), (9), (10) respectively into, can obtain

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc---\left(14\right)$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc---\left(15\right)$

${\mathrm{RSSI}}_3=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(2m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc---\left(16\right)$

Further, the mistiming T of electronic license plate is received according to antenna 1 and antenna 2 ₁, have following formula

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T_1*C---\left(17\right)$

The mistiming T of electronic license plate is received according to antenna 1 and antenna 3 ₂, have following formula

$\sqrt{x^2+y^2}-\sqrt{{(2m-x)}^2+y^2}=T_2*C---\left(18\right)$

Wherein, m is the horizontal range of emitting antenna, and particularly, the horizontal range of antenna 1 and antenna 2 is m, and the horizontal range of antenna 2 and antenna 3 is m, and the horizontal range of antenna 1 and antenna 3 is 2m; T ₁for antenna 1 and antenna 2 receive the mistiming of microwave signal, T ₂for antenna 1 and antenna 3 receive the mistiming of radiofrequency signal, C is the light velocity.

Aggregative formula (14), (15), (16), (17) and (18), obtain system of equations

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_3=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(2m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T_1*C$

$\sqrt{x^2+y^2}-\sqrt{{(2m-x)}^2+y^2}=T_2*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) that above-mentioned over-determined systems can obtain electronic license plate.

As can be seen here, when increasing to 3 antennas by 2 antennas, on the basis increasing antenna, adding extra overdetermined equation formula, can ensureing than adopting the existing method of same antenna number to have higher positioning precision.

It should be noted that, the locating device in the present embodiment also comprises the antenna of more than 3, and its circular is similar with the method for above-mentioned 2 antennas and 3 antennas, often increases an antenna, positioning precision can be improved further, not repeat them here.

In the present embodiment, export positional information and the movement locus of vehicle ' s contour in step S4, specifically comprise:

As shown in Figure 4, according to the coordinate figure (x, y) calculating electronic license plate, and resolve the length and width information of the described vehicle obtained, 4 position coordinateses obtaining vehicle ' s contour can be calculated and be respectively: wherein, p, q are respectively the length of described vehicle and wide.

Further, by the positional information of the above-mentioned vehicle ' s contour of timing acquisition, obtain the movement locus of described vehicle.

Present embodiments provide a kind of vehicle positioning method based on electronic license plate, according to the mistiming of radio signal transmission to different antennae and the size of power level, hybrid algorithm based on mistiming and power level calculates the two-dimensional position information of electronic license plate, and then obtain the positional information of vehicle ' s contour, the number of required receiving antenna in locating device can be reduced, reduce hardware cost, and improve positioning precision simultaneously.

As shown in Figure 5, for another embodiment of the present invention provides a kind of structural representation of the Vehicle positioning system based on electronic license plate, this system comprises: transmitting element 501, receiving element 502, resolution unit 503, location information acquiring unit 504 and vehicle locating unit 505.

Transmitting element 501, for passing through the electronic license plate of electronic license plate locating device timed sending wake-up signal to vehicle, to make described electronic license plate according to described wake-up signal feedback microwave signal to described locating device;

Receiving element 502, for receiving described microwave signal;

Resolution unit 503, for resolving described microwave signal, to obtain in locating device the length and width information that at least two antennas receive mistiming of described microwave signal, power level and described vehicle;

Location information acquiring unit 504, for according to described mistiming and power level, obtains the positional information of the electronic license plate of described vehicle;

Vehicle locating unit 505, for according to the length and width information of described vehicle and the positional information of described electronic license plate, obtains positional information and the movement locus of described vehicle ' s contour.

In the present embodiment, this system also comprises: time synchronized unit, for carrying out synchronously the system time of vehicle electric license plate positioning device each in scanning area.

In the present embodiment, described location information acquiring unit 504, for:

When described electronic license plate locating device comprises 2 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂be respectively the power level that two antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, and T is the mistiming that two antennas receive microwave signal, C is the light velocity, and Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

In the present embodiment, described location information acquiring unit 504, for:

When described electronic license plate locating device comprises 3 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_3=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(2m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T_1*C$

$\sqrt{x^2+y^2}-\sqrt{{(2m-x)}^2+y^2}=T_2*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂, RSSI ₃be respectively the power level that three antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, T ₁for antenna 1 and antenna 2 receive the mistiming of microwave signal, T ₂for antenna 1 and antenna 3 receive the mistiming of radiofrequency signal, C is the light velocity.Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), and Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

In the present embodiment, described vehicle locating unit 505, for:

According to the coordinate figure (x, y) of electronic license plate, and the length and width information of described vehicle, 4 position coordinateses obtaining vehicle ' s contour are respectively: wherein, p, q are respectively the length of described vehicle and wide;

By the positional information of vehicle ' s contour described in timing acquisition, obtain the movement locus of described vehicle.

For system embodiment, due to itself and embodiment of the method basic simlarity, so description is fairly simple, relevant part illustrates see the part of embodiment of the method.

Above embodiment is only suitable for the disclosure is described; and not to restriction of the present disclosure; the those of ordinary skill of relevant technical field; when not departing from spirit and scope of the present disclosure; can also make a variety of changes and modification; therefore all equivalent technical schemes also belong to category of the present disclosure, and scope of patent protection of the present disclosure should be defined by the claims.

Claims (10)

1. based on a vehicle positioning method for electronic license plate, it is characterized in that, the method comprises:

By electronic license plate locating device timed sending wake-up signal to the electronic license plate of vehicle, feed back microwave signal to described locating device to make described electronic license plate according to described wake-up signal;

When described locating device receives described microwave signal, described microwave signal is resolved, to obtain in locating device the length and width information that at least two antennas receive mistiming of described microwave signal, power level and described vehicle;

According to described mistiming and power level, obtain the positional information of the electronic license plate of described vehicle;

According to the length and width information of described vehicle and the positional information of described electronic license plate, obtain positional information and the movement locus of described vehicle ' s contour.

2. method according to claim 1, is characterized in that, described by electronic license plate locating device timed sending wake-up signal to the electronic license plate of vehicle step before, the method also comprises:

The system time of vehicle electric license plate positioning device each in scanning area is carried out synchronously.

3. method according to claim 1, is characterized in that, described according to described mistiming and power level, obtains the positional information of the electronic license plate of described vehicle, comprising:

When described electronic license plate locating device comprises 2 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂be respectively the power level that two antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, and T is the mistiming that two antennas receive microwave signal, C is the light velocity, and Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

4. method according to claim 1, is characterized in that, described according to described mistiming and power level, obtains the positional information of the electronic license plate of described vehicle, comprising:

When described electronic license plate locating device comprises 3 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_3=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(2m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T_1*C$

$\sqrt{x^2+y^2}-\sqrt{{(2m-x)}^2+y^2}=T_2*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂, RSSI ₃be respectively the power level that three antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, T ₁for antenna 1 and antenna 2 receive the mistiming of microwave signal, T ₂for antenna 1 and antenna 3 receive the mistiming of radiofrequency signal, C is the light velocity.Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), and Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

5. method according to claim 1, is characterized in that, described according to the length and width information of described vehicle and the positional information of described electronic license plate, obtains positional information and the movement locus of described vehicle ' s contour, comprising:

According to the coordinate figure (x, y) of electronic license plate, and the length and width information of described vehicle, 4 position coordinateses obtaining vehicle ' s contour are respectively: wherein, p, q are respectively the length of described vehicle and wide;

By the positional information of vehicle ' s contour described in timing acquisition, obtain the movement locus of described vehicle.

6. based on a Vehicle positioning system for electronic license plate, it is characterized in that, this system comprises:

Transmitting element, for passing through the electronic license plate of electronic license plate locating device timed sending wake-up signal to vehicle, to make described electronic license plate according to described wake-up signal feedback microwave signal to described locating device;

Receiving element, for receiving described microwave signal;

Resolution unit, for resolving described microwave signal, to obtain in locating device the length and width information that at least two antennas receive mistiming of described microwave signal, power level and described vehicle;

Location information acquiring unit, for according to described mistiming and power level, obtains the positional information of the electronic license plate of described vehicle;

Vehicle locating unit, for according to the length and width information of described vehicle and the positional information of described electronic license plate, obtains positional information and the movement locus of described vehicle ' s contour.

7. system according to claim 6, is characterized in that, this system also comprises:

Time synchronized unit, for carrying out synchronously the system time of vehicle electric license plate positioning device each in scanning area.

8. system according to claim 6, is characterized in that, described location information acquiring unit, for:

When described electronic license plate locating device comprises 2 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂be respectively the power level that two antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, and T is the mistiming that two antennas receive microwave signal, C is the light velocity, and Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

9. system according to claim 6, is characterized in that, described location information acquiring unit, for:

When described electronic license plate locating device comprises 3 antennas, can obtain according to mistiming and power level:

${\mathrm{RSSI}}_1=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{x^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_2=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

${\mathrm{RSSI}}_3=P-10*{\log }_{10}\frac{{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\sqrt{{(2m-x)}^2+y^2}\right)}^2}+Gr+Gt-Lc$

$\sqrt{x^2+y^2}-\sqrt{{(m-x)}^2+y^2}=T_1*C$

$\sqrt{x^2+y^2}-\sqrt{{(2m-x)}^2+y^2}=T_2*C$

According to Newton iteration method, solve the two-dimensional position coordinate figure (x, y) obtaining electronic license plate;

Wherein, RSSI ₁, RSSI ₂, RSSI ₃be respectively the power level that three antennas receive; P is the emissive power of electronic license plate, and m is the horizontal range of emitting antenna, T ₁for antenna 1 and antenna 2 receive the mistiming of microwave signal, T ₂for antenna 1 and antenna 3 receive the mistiming of radiofrequency signal, C is the light velocity.Gr is receiving antenna gain, and Gt is transmitter antenna gain (dBi), and Lc is the attenuation of cable and cable end, and Gr, Gt, Lc are constant.

10. system according to claim 6, is characterized in that, described vehicle locating unit, for:

According to the coordinate figure (x, y) of electronic license plate, and the length and width information of described vehicle, 4 position coordinateses obtaining vehicle ' s contour are respectively: wherein, p, q are respectively the length of described vehicle and wide;

By the positional information of vehicle ' s contour described in timing acquisition, obtain the movement locus of described vehicle.