JPH0447399A - Vehicle sensor coping with many lanes - Google Patents

Abstract

PURPOSE:To accurately measure a traffic flow by obtaining the sense start time difference, reception levels, the speed difference, and vehicle length in adjacent lanes in accordance with the Dopler signal and the reception level signal of each lane and inputting them to perform fuzzy inference and discriminating passage of one or two vehicles. CONSTITUTION:The vehicle sense processing and the speed measurement processing in each lane are performed by a vehicle presence/absence sensing part 19 and a vehicle speed calculating part 17. It is discriminated whether the sense start time difference between two adjacent lanes is smaller than a prescribed discrimination value or not. When one vehicle runs across lanes, it is considered that the vehicle sense start time difference between both lanes is almost zero, and fuzzy inference is executed thereafter in this case. That is, the speed difference between two adjacent lanes, the vehicle length, and the sum of peaks of reception levels are obtained and are inputted to execute inference in accordance with a fuzzy rule, and the number of vehicles is discriminated. Thus, the traffic flow is measured with a high precision.

Description

[Detailed description of the invention] (a) Industrial application field This invention uses microwave radio waves to send specific information to each vehicle traveling on multiple lanes, and also detects the presence or absence of vehicles in each lane. The present invention relates to a multi-lane vehicle sensor that measures cross-sectional traffic flow.

(b) Conventional technology Conventionally, to measure traffic flow in multiple lanes, ultrasonic vehicle detectors are installed in each lane, and multi-lane vehicle detectors, which the applicant has already applied for, have been used. I have something to use. This multi-lane vehicle sensor has a transmitting antenna that has a directional characteristic that covers all lanes of the multi-lane road, and a directional characteristic that covers only one lane, and It is equipped with a phased array receiving antenna whose characteristics can be switched in time division for each lane, and as a signal processing means for processing the signals transmitted and received by these transmitting and receiving antennas, it is used to provide specific information indicating passing points on the map etc. to the vehicle. a transmission processing unit that outputs a modulated signal for transmitting a signal; a modulation unit that modulates a carrier signal with the modulation signal from the transmission processing unit and outputs the modulated signal to the transmission antenna as a transmission signal; a control signal processing unit that outputs a phase control signal for time-divisionally switching each lane for each lane; and a vehicle that outputs sensing data on the presence or absence of a vehicle in each lane based on the received signal for each lane received by the receiving antenna. It is equipped with a presence/absence signal processing section, and switches the directional characteristics of one receiving antenna in a time-sharing manner corresponding to each lane to cover all lanes.

(c) Problems to be Solved by the Invention As shown in FIG. 10(a), adjacent lanes L1 and L2
When two vehicles are traveling in parallel, regardless of whether the above-mentioned conventional ultrasonic vehicle detector is installed in each lane or a multi-lane vehicle detector is used. , each vehicle can be detected as one vehicle for each lane. However, as shown in Figure 10 et al.
When a vehicle comes across lanes L+ and L2, or when a vehicle enters the sensing area and changes lanes as shown in Figure 10 (C), lanes L+ and LzO The sensing function would work and detect that two vehicles had passed instead of one, causing the problem that accurate cross-sectional traffic flow measurements could not be made.

The present invention has been made by focusing on the above-mentioned problem, and by processing the Doppler signal and received signal level for each lane, it is possible to detect when someone is driving across lanes or in a sensing area. The objective is to provide a multi-lane vehicle sensor that can accurately detect vehicles even when modified, and can accurately measure cross-sectional traffic flow.

(d) Means and operation for solving the problem The multi-lane vehicle sensor of the present invention has a transmitting antenna that is provided on a multi-lane road and transmits and receives microwave signals, and an eleventh and second receiving antenna. The transmitting antenna includes an antenna and a signal processing means for processing transmitted and received signals of the antenna, and the transmitting antenna transmits a directional beam having a directional characteristic covering all lanes of a multi-lane system, , the second receiving antenna is of an array type having a plurality of directional characteristics that cover each lane individually, and the signal processing means transmits specific information indicating passing points on a map etc. to the vehicle. a transmission processing unit that outputs a modulated signal for transmitting a signal; a modulation unit that modulates a carrier signal with the modulated signal from the transmission processing unit and outputs the modulated signal to the transmission antenna as a transmission signal; a vehicle speed calculation unit that calculates a vehicle speed for each lane using a Doppler signal obtained based on the received signal; and a vehicle that detects the presence or absence of a vehicle in each lane based on the received signal for each lane received by the second receiving antenna. a sensing time difference calculation unit that calculates a sensing time difference between adjacent lanes based on the sensing data for each lane from the vehicle presence sensing unit; a parameter calculation unit that calculates parameters such as a peak sum of levels, and a fuzzy controller that executes fuzzy inference using the parameters as input when the sensing time difference is within a predetermined value to infer the number of vehicles traveling in the two adjacent lanes. It is characteristically equipped with an inference section.

In this multi-lane vehicle sensor, microwaves transmitted from a transmitting antenna are reflected by a running vehicle or a road surface and received by first and second receiving antennas. Since both the first and second receiving antennas have directional characteristics corresponding to the lanes, the vehicle speed calculation unit calculates the vehicle speed for each lane based on the received signal from the first receiving antenna. Further, the vehicle presence/absence sensing section detects a vehicle based on the received signal from the second receiving antenna. Here, if the vehicle sensing start time for each adjacent lane is greater than or equal to a predetermined value, data such as vehicle sensing and vehicle speed are output as is. However, if the vehicle sensing start time difference is smaller than a predetermined value, the fuzzy inference section executes inference using the sum of the speed difference, vehicle length, and peak value of the received wave level obtained from the vehicle sensing signal and vehicle speed as input,
It infers whether there is one or two vehicles passing through two adjacent lanes, and outputs the number of vehicles etc. according to the inferred value.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 is a block diagram showing the configuration of a multi-lane vehicle sensor according to an embodiment of the present invention.

In the figure, a multi-lane vehicle sensor 1 includes a transmitting antenna 2 for transmitting microwave radio waves, a first receiving antenna 3 for detecting vehicle speed, and a second receiving antenna 4 for detecting the presence or absence of a vehicle. , a transmitting antenna 2, and a signal processing section 5 that processes transmitted and received signals from the first and second receiving antennas.

The antenna 2.3.4 in this example is as shown in FIG.
It is attached to a pillar P erected on the roadside of a road with three lanes, L, L3.

Although installing each antenna 2.3.4 on the roadside in this way is advantageous from the standpoint of installation workability and aesthetics, it is also possible to install each antenna directly above the center lane L2. The transmitting antenna 2 described above is configured to transmit a directional beam D having a directional angle range that covers all of the lanes L+, Lx, and L3. In addition, the first and second receiving antennas 3
．． 4 both have directional characteristics that cover only one lane, and these directional directions are indicated by symbols A, A', B, and B' in the figure.
, c, and c', this is a phased array system in which the lanes are switched in a time-division manner for each lane. That is, the first and second receiving antennas 3.4 are of a planar antenna type, and as shown in FIG. 3, a large number of antenna elements 6.6, .
Each antenna element 6, 6, . . . has a phase shifter 7 that delays a predetermined phase with respect to the received signal.
．． 7,... are connected.

The signal processing unit 5 includes a transmission processing unit 11 that outputs a modulated signal for transmitting specific information such as passing points on a map to the vehicle, and an oscillator that outputs a high-frequency carrier signal having a constant oscillation frequency. 12, a modulation unit 13 that modulates the carrier signal from the oscillator 12 with the modulation signal from the transmission processing unit 11 and outputs it to the transmission antenna 2 as a transmission signal; a mixer circuit 15 that mixes the signal received by the first receiving antenna 3 with the carrier signal from the distributor 14;
, a low-pass filter 16 that removes high frequency components from the signal output of the mixing circuit 15 and extracts it as a Doppler signal, a vehicle speed calculation unit 17 that calculates the vehicle speed based on this Doppler signal, and the level of the signal received by the second receiving antenna 4. to the level detection unit 18 which detects and outputs a reception level signal to notify the presence or absence of a vehicle, the vehicle presence/absence detection unit 19 which detects the presence or absence of a vehicle based on the reception level signal, and the first and second reception antennas 3.4. The control signal processing section 20 outputs a phase control signal for time-divisionally switching the direction of the directional beam for each lane, a fuzzy inference section 2L, and a vehicle sensing and speed output section 22.

The vehicle presence/absence sensing unit 19 has a function of calculating a sensing time difference between adjacent lanes, a function of determining whether this sensing time difference is smaller than a discriminant value T, and a function of determining whether or not the sensing time difference is smaller than a discriminant value T. It has the function of finding the length. Here, the setting of the determination value T may be changed depending on the vehicle speed calculated by the vehicle speed calculating section 17. In other words, it is made smaller when the vehicle speed is fast, and made larger when the vehicle speed is slow. Also, if there is a difference in vehicle length, select the longer one. Vehicle speed calculation unit 17
has a function that also calculates the speed difference between vehicles in adjacent lanes.

As shown in FIG. 4, the fuzzy inference unit 21 performs sampling hold for inputting the speed difference Xl, the vehicle length X, and the sum X3 of the peak value of the received wave level to the fuzzy inference device 41. Circuit 42, 43, 44, a fuzzy rule memory that stores fuzzy rules for inferring inputs using speed difference x1%, vehicle length x2, and sum of peak values of received wave levels x3, and outputting the possibility of one vehicle. 45
, an amplifier 46 that outputs the inference results from the fuzzy inference device 41. As the fuzzy inference device 41, a dedicated fuzzy controller, CPU, or the like is used. However, the fuzzy inference section 2 used here
The configuration of No. 1 itself is already well known.

The fuzzy rule memory 45 stores the following fuzzy rules.

■if x+=ZR, Xz=PS, Xx=Z
R■if ■if ■if ■if ■if ■if ■if ■if [phase] if ■1f then (if) y XI =ZR,Xz =PS, then y+=PL x, =ZR1χ, =PL, then y,=pL.

x+ = ZR, Xz = PM, then y,=PL x, = PS, χ2 = PS.

then 　　　)’、=PM x+ = PS, xz = PS.

then y + = P M x1=PS, X2=PL.

then y, = PM XI = PS, X2 = PM.

then yl=PM xl=...Xz==ps.

then y,=PS XI--X2=PL.

then)z=PS x, =-Xz = ps.

PL x, -PS PS =PL =ZR PS =PL PL =PM =PL =PL then y+=ZR @if XI =-= x, =PM, x, =
PLthen y+=ZR ■if x,=PL,,Xz=... x3
=...then y, =ZR Speed difference χ1 used in this fuzzy rule, vehicle length Xz
, the input of the sum of the peak values of the received wave levels for two lanes χ, and the membership function examples of the output of the probability yI of one vehicle are shown in Figures 5, 6, 7, and 8, respectively. It shows. Here - ZR is zero for boat fishing, PS is a little small, P
M means a little big, PL means big.

Next, the operation of the multi-lane vehicle sensor 1 configured as described above will be explained.

In this multi-lane vehicle sensor 1, a high frequency carrier signal from an oscillator 12 is distributed by a distributor 14 to a modulating section 13 and a mixing circuit 15. In parallel with this, the transmission processing unit 11 outputs a modulated signal for transmitting specific information indicating passing points on the map to the vehicle M. The modulator 13 modulates the carrier signal with a modulation signal and outputs it to the transmitting antenna 2 as a transmitting signal. As a result, from the transmitting antenna 2, each lane L+, LzL,
A microwave directional beam D having a directional characteristic covering all of the above is transmitted, and the above specific information is sent to the vehicle M traveling in each lane 3, Lz, L. Therefore, when a vehicle M equipped with a dedicated receiver capable of receiving this radio wave passes over this sensor 1, specific information can be received.

On the other hand, a phase control signal is given from the control signal processing unit 20 to each phase shifter 7.7, . Since the time is set, as a result, both receiving antennas 3.4 are synchronized with each other so that their directional directions are indicated by the symbols A, A', and A' in the figure.
As shown by B, B', C, C'', each lane is switched in a time-sharing manner.As a result, each lane L+, Lz
, L3, and the radio waves reflected from the road surface are transmitted to each lane L by the first and second receiving antennas 3.4.
3. Received every Lz, L:l.

The received signal received by the first receiving antenna 3 is mixed with a carrier signal in a mixing circuit 15, a signal with a frequency difference between both signals is extracted, and a high frequency component of this signal output is removed by a low-pass filter 16. It is output as a Doppler frequency proportional to the speed of the vehicle in each lane. and,
A vehicle speed calculation unit 17 calculates the vehicle speed based on the Doppler frequency for each lane and outputs the data. Further, the received signal received by the second receiving antenna 4 is detected by the level detecting section 8, and a received level signal having a voltage value corresponding to the level of the received signal is output. The vehicle non-sensing unit 19 outputs sensing data regarding the presence or absence of a vehicle based on this reception level signal.

In addition, the vehicle sensing unit 19 performs vehicle sensing for each lane as described above, but if the vehicle sensing start times are almost the same in adjacent lanes, a fuzzy method is used to determine whether there is one vehicle or two vehicles. The inference section 21 performs this, and the vehicle sensing and speed output section 22 outputs an output according to the result. On the other hand, if vehicle sensing start times are different in adjacent lanes, the fuzzy inference section 21 does not perform inference, and the vehicle sensing and speed output section 22 outputs data such as the number of vehicles, speed, etc.

Next, the processing operation for determining whether the number of vehicles is one or two will be explained with reference to the flowchart shown in FIG. First, the vehicle presence/absence sensing section 19 and the vehicle speed calculation section 17 perform vehicle sensing processing and speed measurement processing for each lane (step 5TI). and,
It is determined whether the sensing start time difference between two adjacent lanes is smaller than a predetermined determination value (T) (step 5T2
).

If the sensing time difference is larger than the discriminant value (T), it is considered that different vehicles are traveling in each lane with a time difference, so in this case, fuzzy inference is not performed and vehicle sensing and speed output are (Step 5T5). but,
For example, when one vehicle is running across lanes as shown in FIG. 11(b), it is considered that there is almost no difference in the vehicle detection start time of both lanes, and in such a case, step ST2 The determination becomes YES, and fuzzy inference is executed thereafter. That is, the speed difference between the two adjacent lanes, the vehicle length (select the longer one), and the sum of the peaks of the received wave level are calculated (step 5T3), and these are input and inference is executed according to the fuzzy rules described above, and the vehicle Determine the number of units (
Step 5T4). Then, the number of vehicles and speed are output according to the results (step 5T5). When the inference value (possibility of one vehicle) is 0.5 or more, it is determined that there is only one vehicle even if there is a vehicle detected in two adjacent lanes, and conversely, if it is less than 0.5, there are two vehicles. I judge that.

Note that in the above embodiment, phased array antennas are used as the first and second receiving antennas, and the directional characteristics are switched in a time-division manner in accordance with the lanes; however, the present invention is limited to time-division switching. Instead, a phase shifter is installed to distribute the element signals of the element array antenna corresponding to the lanes and to delay the distributed signals, and by changing the amount of delay by the phase shifter, each lane can be distributed with one antenna. An antenna having directional characteristics that can individually cover the following may be used.

(F) Effects of the Invention According to the present invention, a Doppler signal for each lane is obtained by using a multi-lane vehicle sensor that employs an element array antenna having multiple directional characteristics corresponding to each lane as one receiving antenna. , find the difference in sensing start time for each adjacent lane from the received wave level signal, the difference in the size and speed of the received wave level, and the vehicle length, and use these as input to perform fuzzy inference to determine whether one vehicle or two vehicles are passing. Now, if the vehicle is running across two lanes or
Even if you change lanes in the vehicle detection area, 1 will work normally.
This system has the effect of being able to determine whether a vehicle has passed, allowing for accurate judgment and traffic flow measurement.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a multi-lane vehicle sensor showing an embodiment of the present invention, and FIG. 2 is a block diagram of a multi-lane vehicle sensor in which a transmitting antenna and a receiving antenna are installed on a road. FIG. 3 is a perspective view showing the state; FIG. 3 is an explanatory diagram of the switching operation of the directional beam of the receiving antenna element; FIG. 4 is a block diagram showing the configuration of the fuzzy inference section of the multi-lane vehicle sensor of the above embodiment. , FIG. 5 is a diagram showing the membership function of the speed difference input to the fuzzy inference section, and FIG.
Figure 7 is a diagram showing the membership function of the vehicle length input to the fuzzy inference unit, and Figure 8 is a diagram showing the membership function of the sum of the peak values of the received wave levels input to the fuzzy inference unit. The figure is a diagram showing the membership function of the possibility of one vehicle, which is the output of the fuzzy inference section, and FIG. 9 is a flow diagram for explaining the process of determining the number of vehicles in the multi-lane vehicle sensor. , FIG. 10(a), FIG. 10(b),
FIG. 10(C) is a diagram illustrating a vehicle running state in a multi-lane vehicle. 1: Multi-lane vehicle detector, 2: Transmitting antenna, 3: First receiving antenna, 4:
2nd receiving antenna, 5: signal processing section, 11: transmission processing section, 13: modulation section, 17: vehicle speed calculation section, 19: vehicle presence/absence sensing section, 21: fuzzy inference section, 22:
Vehicle sensing speed output section. 181

Claims (1)

[Claims] (1) It includes a transmitting antenna and first and second receiving antennas that are installed on a multi-lane road and transmits and receives microwave signals, and has a signal processing means that processes the transmitted and received signals of the antenna, The transmitting antenna is
The system transmits a directional beam having a directional characteristic that covers all lanes of a multi-lane vehicle, and the first and second receiving antennas are array-type beams that have a plurality of directional characteristics that individually cover each lane. The signal processing means includes a transmission processing unit that outputs a modulated signal for transmitting specific information indicating passing points on a map etc. to the vehicle; a modulation unit that modulates a signal and outputs it as a transmission signal to a transmission antenna; a vehicle speed calculation unit that calculates a vehicle speed for each lane using a Doppler signal obtained based on a signal received by the first reception antenna; a vehicle presence/absence sensing unit that detects the presence or absence of a vehicle in each lane based on a received signal for each lane received by a receiving antenna; a sensing time difference calculation unit that calculates a sensing time difference; a parameter calculation unit that calculates parameters such as a speed difference between the two adjacent lanes, a vehicle length, and a peak sum of received wave levels; when the sensing time difference is within a predetermined value; A multi-lane vehicle sensor comprising: a fuzzy inference unit that executes fuzzy inference using the parameters as input to infer the number of vehicles traveling in the two adjacent lanes.