WO2014101665A1

WO2014101665A1 - Positioning method and system using a passive multi-beam antenna

Info

Publication number: WO2014101665A1
Application number: PCT/CN2013/089242
Authority: WO
Inventors: 王致远; 段起志
Original assignee: 北京握奇智能科技有限公司
Priority date: 2012-12-24
Filing date: 2013-12-12
Publication date: 2014-07-03
Also published as: CN103901399A; CN103901399B

Abstract

A positioning method and system using a passive multi-beam antenna, and belong to the field of intelligent communication. In an existing method, a plurality of positioning modules or an active phased array module may be used to measure the position of a vehicle in a vehicle lane. The method comprises the following steps: (1) generating a plurality of wave beams in one positioning module in a passive manner, and collecting signals sent by a same on board unit (OBU); (2) obtaining a magnitude and a phase signal of each wave beam by using a wave detector and a phase discriminator in the positioning module, respectively, and performing digitization by using A/D sampling to obtain a digital signal; and (3) performing processing on the digital signal to obtain information about the final position of the OBU. By adopting the method and system, the demand for positioning of free traffic can be implemented, and high positioning precision is achieved at low cost and in a simple manner.

Description

Method and system for positioning using passive multi-beam antenna

The invention belongs to the field of intelligent transportation technology, and particularly relates to a method and system for positioning by using a passive multi-beam antenna. Background technique

The emergence of the ETC system (Electric Toll Collect) has changed the traditional way of manual charging, so that when the vehicle passes through the toll station of a highway, bridge or tunnel, the payment process can be completed without parking, which greatly improves the process. The utilization of roads has increased the speed of vehicles, reduced traffic congestion, and reduced carbon emissions to some extent. At the same time, the labor demand of the toll station is reduced, and the operating cost of the toll lane is reduced. Non-stop charging methods are used by more and more countries and cities.

With the development of the economy, the problem of traffic congestion caused by the rapid growth of urban vehicles is becoming more and more serious. The traditional ETC adopts a single lane setting, one car and one pole, the vehicle passing speed is difficult to exceed 40km/h, and the lane equipment occupies a large road surface, which is not suitable for tunnels, bridges or toll gates with limited width.

The multi-lane free-flow charging method does not set the lane railing, and there is no isolation between the multiple lanes, so that the vehicle passing speed is further improved, and the toll station is no longer a road congestion level. It also reduces the cost of the road infrastructure and the area occupied by the road, which is especially important for road and bridge tolls and tunnel tolls. In addition, some countries with severe urban congestion also adopt multi-lane free-flow charging methods to implement congestion charging. According to the time period, the vehicles entering the congested road sections are charged, the number of vehicles is limited, and the congestion situation is alleviated.

Multi-lane free flow is a way of electronic non-stop charging. It differs from the traditional ETC system in that it does not divide lanes and does not use railings. The vehicle can pass directly without any deceleration and can be driven in any line. For a free-flow system, the frame diagram is shown in Figure 1.

The block diagram of the multi-lane free-flow system is shown in Figure 2. The multi-lane free-flow system is mainly composed of the following parts: On-board electronic tag 0BU (On Board Unit), electronic tag read/write antenna RSU (Roadside Unit, road test) Unit), vehicle detection and vehicle positioning, image capture and license plate recognition, lane coordination system and settlement background. When the OBU-equipped vehicle passes through the free-flow toll station, the whole system works as follows: Model identification: Before the vehicle passes through the gantry, the vehicle detection and vehicle identification system uses laser grating scanning to obtain the passing size of the vehicle, determine the vehicle type, and pay as a fee. Basis of the amount; Microwave positioning: By receiving the RF signal transmitted by 0BU, the 0BU is positioned, together with the vehicle identification function, to determine whether the model registered on the 0BU is consistent with the actual model, and if it is inconsistent, it is recorded in the background, and the violation is handled;

Tag reading and writing: When the vehicle enters the RSU antenna coverage area, 0BU is activated and begins to communicate with the RSU for authentication. Normally, after confirming that 0BU is legal, RSU records the MAC number of the 0BU as the basis for payment, and completes the deduction in the background system and generates the transaction serial number at the same time. Image capture: At the same time as the communication transaction, the image capture system Capture the photo of the vehicle and identify the license plate. The captured image is also automatically generated by the serial number (the rule is the same as the transaction serial number), which matches the transaction serial number and is automatically transferred to the save; the image that cannot be associated with the transaction serial number is determined to be a violating vehicle, and is used as the basis for cost recovery.

Since the free flow does not restrict the lane of the incoming vehicle, it also needs to check the illegal vehicle. Therefore, it is necessary to match the vehicle and the installed 0BU. The existing matching method is to measure the position of the vehicle body with a laser grating, and simultaneously use the microwave. The positioning method measures the position of the 0BU and matches the positions of the two to finally achieve the pairing of the vehicle and the 0BU.

The multi-lane free-flow charging method has attracted the attention of many countries and cities and is an important development direction in the future intelligent transportation field. The need to locate the vehicle 0BU has been raised in the use of free flow. There are two main types of existing positioning solutions:

The first solution is to install the RSU in the gantry at intervals of about lm, extract the amplitude information of 0BU from each RSU, and obtain the position information of 0BU through the corresponding algorithm. The advantage of this solution is that the design and implementation of a single module is relatively simple; the disadvantage of this solution is that there are a large number of RS U modules required, and about ten modules are required for three lanes. The consistency requirements of each module are high, calibration is difficult and the topology of the module cascade is more complicated.

The second solution is to use the phased array antenna for positioning, that is, the active phase shifting device realizes multiple beams at different time points, and uses the phase and amplitude information obtained by different beams to realize positioning by corresponding algorithms. The advantage of this scheme is that the number of modules is small, and only one lane is needed. The disadvantage of this scheme is that the hardware is difficult, the cost is high, the average fault-free time of the product is short, and each beam is time-division, and the positioning difficulty is increased. Summary of the invention

In view of the deficiencies in the prior art, it is an object of the present invention to provide a method and system for positioning using a passive multi-beam antenna. The method and system can utilize the method of passive multi-beam to realize the requirement of free-flow positioning, and achieve higher positioning accuracy at a lower cost and in a simpler manner. To achieve the above objective, the technical solution adopted by the present invention is: A method for positioning using a passive multi-beam antenna, comprising the following steps:

(1) generating a plurality of beams in a positioning module by passive means, and collecting signals of the same 0BU vehicle unit;

(2) Obtaining the amplitude and phase signals of each beam by using the detector and the phase detector in the positioning module respectively, and digitizing the digital signals by using A/D sampling;

(3) Processing the digital signal to obtain the final position information of 0BU. Further, in the step (1), the number of beams generated in one positioning module in a passive manner is 2 to 10, and the preferred number is 3 to 8. Further, in step (2), finding the maximum value in the amplitude information of all the beams, and adding the amplitude values obtained by the other beams as the auxiliary information, using the fitting algorithm to determine the deflection angle of the 0BU vehicle unit relative to the positioning module in the azimuth plane .

Further, in the step (2), for the phase information, the phase change is 2 π for one wavelength, and the wavelength of the signal is a known λ, which is determined by the equation AL=A δ * λ /2 π , and the phase difference Δ δ The distance difference AL is obtained, and the position of the 0BU is obtained from the azimuth plane deflection angle of the OBU with respect to the positioning module by the plane geometry algorithm. A system for positioning by using a passive multi-beam antenna includes an RSU drive test unit and an 0BU onboard unit. The RSU includes a transaction module and a positioning module, wherein the positioning module includes the following devices: a multi-beam antenna unit, and a plurality of A signal detecting unit and a signal phase detecting unit connected to the beam antenna unit, a detection A/D unit and a phase-detecting A/D unit respectively connected to the signal detecting unit and the signal phase detecting unit, and a detection A/D unit and phase discrimination A/ a central processing unit CPU connected to the D unit; The multi-beam antenna unit is configured to generate multiple beams by using a passive manner; the signal detection unit is configured to extract amplitude information of the 0BU signal obtained by each beam; and the signal phase-detecting unit is configured to extract phase information of the 0BU signal obtained by each beam. The detection A/D unit and the phase-detecting A/D unit are used to convert the analog signal to the digital signal; the central processing unit CPU is used to process the digital signals of the beam amplitude and phase, and the final OBU position coordinates are obtained by corresponding algorithms. The effect of the invention is that: by adopting the method of the invention, the requirement of free flow positioning can be realized by the scheme of passive multi-beam, and the higher positioning precision is achieved at a lower cost and in a simple manner. DRAWINGS

Figure 1 is a schematic diagram of the composition of a multi-lane free-flow system;

Figure 2 is a block diagram of the multi-lane free-flow system;

3 is a flow chart of a method for positioning using a passive multi-beam antenna according to the present invention; FIG. 4 is a schematic diagram of a system structure diagram of the present invention;

Figure 6 shows the left lobe of the main lobe 15 . Azimuth plane pattern;

Figure 7 is a front view of the main lobe;

Figure 8 is the right lobe of the main lobe 15. Azimuth plane pattern;

Figure 9 is a schematic diagram of the location of the 0BU and each beam module. detailed description

The invention is further described below in conjunction with the drawings and specific embodiments. The method proposed by the invention is to generate multiple beams in a passive manner relative to the single unit, and perform phase detection and detection on each beam port to realize extraction of the positioning information.

As shown in FIG. 4, a system for positioning by using a passive multi-beam antenna includes the following devices: RSU road test unit, used for the road test end of the ETC transaction, realizing the pairing transaction with the 0BU and the pair OBU positioning;

OBU on-board unit, used for ETC transaction on the vehicle side, to achieve pairing transaction with RSU; RSU includes transaction module and positioning module, and the positioning module includes multi-beam antenna detector, phase detector, A/D sampler and central Processor CPU;

Wherein, the multi-beam antenna is used to generate multiple beams;

The detector is configured to extract amplitude information of the OBU signal obtained by each beam;

The phase detector is configured to extract phase information of the OBU signal obtained by each beam;

The A/D sampler converts the analog signal to the digital signal;

The CPU is used to process the digital signals of each beam amplitude and phase, and obtain the final OBU position coordinates through the corresponding algorithm. The present invention relates to an OBU microwave positioning technology, as shown in steps S1-S8 of FIG. 3, a method for positioning using a passive multi-beam antenna, comprising the following steps:

(1) The RSU issues a transaction initiation signal;

(2) 0BU returns a transaction response signal;

(3) The amplitude detector of the 0BU signal obtained by each detector in the positioning module is extracted by the detector, and the digital signal is uploaded to the CPU after A/D sampling, and the 0BU position is obtained from each signal amplitude information by the corresponding algorithm;

(4) The phase detector of the positioning module extracts the phase information of the 0BU signal obtained by each beam, and after the A/D sampling, uploads the digital signal to the CPU, and obtains the 0BU position from each signal phase information through the corresponding algorithm;

(5) Combining the results obtained by the two algorithms to obtain the final 0BU position coordinates, uploading the lane master control software;

(6) The lane software completes the positioning by comparing the vehicle position with the 0BU position. In this embodiment, if the number of passive beams is N, amplitude information Al, A2, Α3···Αη; and phase information δ 1 , δ 2, δ 3··· δ η can be obtained. In the actual application process, Ν is usually 2

- 10, preferably 3 - 8, in the present embodiment, Ν is 3. Since the amplitude information obtained by the beam pointing to the 0BU is the largest, for the amplitude information, the idea of the processing algorithm is to find the maximum value in all the amplitude information, and add the amplitude value obtained by the other beams as the auxiliary information, and use the fitting. The algorithm determines the angle of deflection of the OBU relative to the positioning module at the azimuth plane. For the phase information, since the phase center of each beam has a fixed relative distance in the azimuth plane, the distance from the 0BU signal to the center of each beam phase is different, resulting in a phase difference. For a wavelength phase change of 2 π, the wavelength of the signal is known. λ , the distance difference can be obtained from the phase difference by the formula AL= A δ * λ / 2 π, and the position of 0BU is obtained from the azimuth plane deflection angle of 0BU with respect to the positioning module by the plane geometry algorithm. The data obtained by the amplitude and phase are weighted (the weight is corrected by the actual test effect), and the angle information of the 0BU relative multi-beam positioning module is obtained. Then, the angle information of each positioning module is integrated, and the focus of the deflection extension line is found as the position information of the 0BU. The position information includes not only the lateral position information of the 0BU on the lane, but also the longitudinal position information of the gantry. The present invention combines the advantages of the two existing solutions, and has the following advantages:

1. The number of modules is small, the topology structure is simple, and only one device is needed for one lane.

2, module hardware to achieve a single, low cost, high stability

3, antenna consistency is easy to achieve, you can control the phase center as much as possible

4. Simultaneously process amplitude and phase information to improve positioning accuracy

5. Colleagues who get horizontal positioning information can also get vertical positioning information.

The implementation of the multi-beam antenna can be: horn, arbor, microstrip, spiral, paraboloid, and the like. There is an array implementation of phase differences.

The angle of deflection is from 0 degrees (normal) to 90 degrees (parallel).

Due to the low profile, consistency, and processability of the product, the microstrip antenna is an ideal implementation. The present invention uses a microstrip array three-beam microstrip antenna as an example, and the specific indicators are as follows:

Beam width 40° (pitch) χ 20° (azimuth)

Standing wave ratio is less than 1. 5

Beam pointing -1 5°, 0°, 15° (azimuth deflection).

Based on the requirements of the antenna beam width, the array element adopted in this design is a 2 X 4 array specific form as shown in Fig. 5.

To ensure that the cell spacing is 0.7 times the wavelength, the selected cell has a lateral spacing of 36 mm and a longitudinal spacing of 34 mm. Beam pointing adjustment can be performed by adjusting the phase relationship between the various units. When each When the unit phase is the same, the beam is directed to the normal direction; when there is a phase difference between the units, the ratio is 68.9. The beam can be pointed at 15. ; When there is a phase difference between -68. The beam can be pointed at -15. . The specific direction is shown in Figure 6, Figure 7, and Figure 8.

It can be seen from the three different directed directions that the amplitude information obtained by the three beams of the incident signal at a fixed angle is different, so that the mapping of the amplitude difference to the incident angle can be obtained.

When the signal sent by a 0BU arrives at the center of the three beam phases, there is a distance difference such as L1 and L2 shown in Fig. 9. Since the distances of signals transmitted in space are different, the distance difference will produce the phase difference obtained by each beam phase detector. If there is a phase difference δ ΐ between beams 1 and 2, the difference between the beams of 3 and 3 is δ 2 . Since L = X * 5 /2 TT. Therefore, Ll and L2 can be obtained from δ 1 and δ 2 . Because the spacing of the three beams is known, the position of the signal source can be obtained by the planar geometry method.

The above describes a method of performing positioning using a passive multi-beam positioning module, and an implementation of a passive multi-beam antenna. It should be understood by those skilled in the art that the present invention is not limited to the embodiments of the present invention. Those skilled in the art will be able to devise other embodiments in accordance with the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

Rights request

1. A method of positioning using passive multi-beam antennas, including the following steps:

(1) Use a passive method to generate multiple beams in a positioning module and collect signals from the same 0BU (vehicle-mounted unit);

(2) Use the detector and phase detector in the positioning module to obtain the amplitude and phase signals of each beam, and use A/D sampling to digitize to obtain the digital signal;

(3) Process the digital signal to obtain the final position information of 0BU. 2. A method of positioning using a passive multi-beam antenna as claimed in claim 1, characterized in that: in step (1), the number of beams generated in a positioning module in a passive manner is 2 to 1 0.

3. A method of positioning using a passive multi-beam antenna as claimed in claim 2, characterized in that: in step (1), the number of beams generated in a positioning module in a passive manner is 3 to 8 indivual.

4. A method of positioning using a passive multi-beam antenna as claimed in claim 1, 2 or 3, characterized in that: in step (2), find the maximum value in the amplitude information of all beams, and add other The amplitude value obtained by the beam is used as auxiliary information, and the fitting algorithm is used to determine the deflection angle of the OBU vehicle-mounted unit relative to the positioning module in the azimuth plane.

5. A method of positioning using a passive multi-beam antenna as claimed in claim 1, 2 or 3, characterized in that: in step (2), for the phase information, for one wavelength the phase change is 2π, the signal The wavelength of is known λ. According to the formula A L= A δ * λ /2 π, the distance difference Δ L can be obtained from the phase difference Δ δ. Then, the plane geometry algorithm is used to calculate the deflection angle of the OBU relative to the azimuth plane of the positioning module. Get the position of 0BU.

6. A system that utilizes passive multi-beam antennas for positioning, including an RSU drive test unit and an OBU vehicle-mounted unit. The RSU includes a transaction module and a positioning module. It is characterized in that the positioning module The block includes the following devices: a multi-beam antenna unit, a signal detection unit and a signal phase detection unit connected to the multi-beam antenna unit, a detection A/D unit and a phase detection A/D unit respectively connected to the signal detection unit and the signal phase detection unit. , a central processing unit CPU connected to the detection A/D unit and the phase detection A/D unit; wherein, the multi-beam antenna unit is used to generate multiple beams in a passive manner;

The signal detection unit is used to extract the amplitude information of the 0BU signal obtained by each beam; the signal phase detection unit is used to extract the phase information of the 0BU signal obtained by each beam; the detection A/D unit and the phase detection A/D unit are used to implement analog signals Conversion to digital signals; The central processing unit CPU is used to process the digital signals of the amplitude and phase of each beam, and obtain the final 0BU position coordinates through the corresponding algorithm.

7. A system for positioning using passive multi-beam antennas as claimed in claim 6, wherein

8. A system for positioning using passive multi-beam antennas as claimed in claim 7, wherein

9. A system for positioning using a passive multi-beam antenna as claimed in claim 6, wherein the method for the signal detection unit to extract the amplitude information of the OBU signal obtained from each beam is: Find the maximum value in the amplitude information, add the amplitude values obtained from other beams as auxiliary information, and use the fitting algorithm to determine the deflection angle of the OBU vehicle-mounted unit relative to the positioning module in the azimuth plane.

10. A system for positioning using a passive multi-beam antenna as claimed in claim 6, characterized in that the method for the signal phase detection unit to extract the phase information of the OBU signal obtained from each beam is: for the phase Information, for a wavelength whose phase change is 2 π and the wavelength of the signal is known λ, according to the formula A L= A δ * λ / 2 π, the distance difference A L can be obtained from the phase difference Δ δ, and then through the plane geometry algorithm: The position of 0BU is obtained from the deflection angle of 0BU relative to the azimuth plane of the positioning module.