JPH0443497A - Car sensor corresponding to multiple lanes - Google Patents

Abstract

PURPOSE:To reduce cost by obtaining a received signal for each line by a directional characteristic corresponding to each lane. CONSTITUTION:In a modulation part 13, a carrier signal is modulated by a modulation signal and transmitted to a transmission antenna as a transmitted signal. In this case, the transmission antenna 2 transmits a directional beam D of a microwave having the directional characteristic so as to cover all respective lanes L1, L2 and L3, and specified information is obtained to cars M traveling in the respective lanes L1, L2 and L3. Namely, when the car M equipped with an exclusive receiver to receive this radio wave passes on a sensor 1, the specified information can be received. Thus, the total cost can be drastically cut.

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. This invention relates to a multi-lane vehicle sensor.

(b) Conventional technology Conventionally, as a multi-lane sensor that detects vehicles traveling on multiple lanes, a transmitting antenna with a directional characteristic that covers all lanes of the multi-lane road and a single lane The vehicle is equipped with a phased array type receiving antenna that has a directional characteristic that covers only 300 kHz and whose directional characteristic is time-divisionally switched for each lane. There is a transmission processing unit that outputs a modulated signal for transmitting specific information indicating 1llll passing points on the map, etc., and a carrier signal is modulated with the modulation signal from this transmission processing unit and sent to the transmission antenna as a transmission signal. a control signal processing unit that outputs a phase control signal for time-divisionally switching the pointing direction of each lane with respect to the receiving antenna; A system has already been proposed that includes a vehicle presence/absence signal processing section that outputs sensing data on the presence or absence of vehicles in each lane.

(c) Problems to be Solved by the Invention The conventional multi-lane vehicle sensor described above controls the elements of a phased array antenna that controls the directivity of the antenna for each lane in a time-sharing manner. Because the system monitors vehicles passing through each lane in a time-divided manner, there was a risk that the accuracy of sensing and speed calculations would drop. Furthermore, since a switch using an expensive PiN diode is used to switch the phase of the phase shifter that controls the directivity of the antenna, there is a problem in that the cost of the sensor becomes very high.

This invention was made by focusing on the above-mentioned problems, and is a multi-lane vehicle that can achieve the same accuracy as a single-lane type even when supporting multiple lanes, and can reduce costs by eliminating the need for expensive switches. The purpose is to provide a sensor.

(d) Means and operation for solving the problems The multi-lane vehicle sensor of the present invention is provided on a multi-lane road and includes a transmitting antenna and a receiving antenna for transmitting and receiving microwave signals, and The receiving antenna is of an array type in which a plurality of elements are arranged in parallel,
In a multi-lane vehicle sensor that processes a signal for each lane obtained from a receiving antenna in a signal processing unit to detect the presence or absence of a vehicle in each lane, calculate vehicle speed, etc., the signal obtained from each element of the receiving antenna is processed. It is equipped with a distributor that distributes the received signal according to the number of lanes, and a plurality of phasers that delay the distributed signal by a predetermined phase so that directional characteristics corresponding to each lane can be obtained. The reception signal for each lane is obtained using the directional characteristics corresponding to the directional characteristics.

In this multi-lane vehicle sensor, the received signal reaching each element of the receiving antenna is distributed to each lane by a distributor. Then, the distributed reception signal corresponding to each lane is delayed by a predetermined phase corresponding to each element by the corresponding phase shifter, and therefore the signal output from each phase shifter corresponding to each lane corresponds to each lane. received by an antenna with directional characteristics. That is, Doppler signals from vehicles traveling in each lane are simultaneously received by one receiving antenna.

(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 sensing vehicle speed, and a second receiving antenna 4 for not sensing a vehicle. and a signal processing section 5 that processes the transmission and reception signals of the transmitting antenna 2 and 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, and , L.

Although installing each antenna 2.3.4 on the roadside in this way is advantageous from the viewpoint of installation workability and aesthetics, it is also possible to install each antenna 2.3.4 directly above the center lane. The above-mentioned transmitting antenna 2 is configured to transmit a directional beam D having a directional angle range that covers all of the lanes L1, L2, and L3. In addition, the first and second receiving antennas 3.4
is of an array type, which has a plurality of directional characteristics A, A', B, B', C, and C' which together can individually and independently cover each lane.

The first and second receiving antennas 3.4 are of a planar antenna type, and as shown in FIG.
9.6. ．． 6. and each antenna element 6p, 6
．． ．． 6. ．． 6. are splitters 72.7, . . . which distribute the received signal to each lane. 7. ．． 7s, and the output corresponding to each lane of the distributor 7p is connected to a phaser 8□, 8p2.8 for delaying the phase in order to form a directional characteristic corresponding to the lane.
p3 and similarly each distributor 79.7, . 7. The output corresponding to each lane is also phaser 8 Q8, 84g, 811.
．． Connected to 8□, 8,2, 8r3.8□, 8s□, and 8.3. Phaser 8-18. The outputs of ll, 8-18□ are sent to the phase shifter 8□, as received signals with directivity characteristics A and A'.
The outputs of 80.8□ and 81 are used as received signals with directional characteristics B and B'', and the outputs of phase shifters 8 ps and 8q3.8.3.8° are used as received signals with directional characteristics c and c', respectively. This phaser apl, 80, . . . is derived simultaneously.
85. For example, a microstrip line can be used by simply changing the length of the feed line. In this receiving antenna, if we focus on the directional characteristic A (A'), and if the plane indicated by the straight line a corresponds to the directional characteristic A, then since the distance from the element 6F to the wave surface a is long, its quantile assembly apl On the other hand, since the distance from element 6 to wave surface a is small, the quantile assembly 8□ is made longer so that the phases match at the output derivation point. The other directional characteristics B (Bo) and C (C') are also considered in the same way.

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; -1
．． 15-2. A distributor 14 that distributes to 15-3, a directional characteristic A corresponding to each lane received by the first receiving antenna 3,
A mixing circuit 15 for mixing the received signals of B and C with the carrier signal from the distributor 14. ,,． 15-2.154, Mixed circuit 1
5-1.15-2.15-3 receives the Doppler signal for each lane of the three lanes and calculates the vehicle speed for each lane, and the second receiving antenna 4 receives the Doppler signal. Directional characteristics A', D', C' corresponding to each lane
level detection unit 17-1.17- that detects the level of the received signal and outputs a received level signal that indicates the presence or absence of a vehicle.
2.171, it is equipped with a vehicle presence/absence sensing section 18 that senses the presence or absence of a vehicle based on a received level signal.

Next, the operation of the multi-lane vehicle sensor 1 according to the embodiment 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 modulator 13 and a mixing circuit 15-1.15-2.15-3.

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,,L,! A microwave directional beam D having a directional characteristic covering all of the above is transmitted, and the above-mentioned specific information is sent to the vehicle M running in each lane L+, Lm, and Lx. 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, the radio waves reflected by vehicles traveling in lanes L+, Lm, and L3 or from the road surface have directional characteristics corresponding to wavefront a shown in FIG. The signal with the directional characteristic B corresponding to the wavefront C is used as the received signal from the lane L2, and the signal with the directional characteristic B corresponding to the wavefront C is used as the received signal from the lane L3. The received signal is inputted to the carrier signal from the distributor 14 and mixed with the carrier signal from the distributor 14, and the received signal is converted into a Doppler frequency signal proportional to the vehicle speed for each lane by the vehicle speed calculation unit 18 for each lane. The vehicle speed is calculated based on the Doppler frequency and the data is output.

Further, the received signal for each lane received by the second receiving antenna 4 is detected by level detection units IL, 17-z, and 17-1 to generate a received level signal having a voltage value corresponding to the level of the received signal. is output. The vehicle presence/absence sensing unit 18 is
Sensing data on the presence or absence of a vehicle is output based on this reception level signal.

In addition, in the first receiving antenna 3 and the second receiving antenna 4, the signal obtained by the antenna element is distributed, so the drop is -3 dB when there are two lanes and 4.7 dB when there are three lanes. Even in a variable phase shifter configured as shown in FIG. Further, although the mixing circuit and the level detection circuit section require the number of lanes, the variable phase shifter can be omitted, so the combination cost can be greatly reduced.

(F) Effects of the Invention According to the present invention, received signals obtained from a large number of antenna elements are distributed to a number corresponding to each lane, and a predetermined signal is distributed to each antenna element so that a directional characteristic corresponding to each lane is obtained. Since it is equipped with a phase shifter that delays the phase by the phase of Pi that is expensive and has no
Since an N diode switch is also not required, there is an effect that the total cost can be significantly reduced.

[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, a perspective view showing the state, is an explanatory diagram of the configuration and directional characteristics of the receiving antenna. 1: Multi-lane sensor, 2: Transmission antenna, 3: First
Receiving antenna, 4: Second receiving antenna, 5: Signal processing unit, 62 ・6q ・6r ・6s: Antenna element, 72 ・7q ・71 ・7s: Distributor, 8 p+
...893.8ql...L3.8rl...
...8.1.8□...8,: Phaser. Patent applicant OMRON Co., Ltd. agent
Patent Attorney Shigeru Nakamura Diagram Diagram A'B'C'

Claims (1)

[Claims] (1) A transmitting antenna and a receiving antenna are provided on a multi-lane road to transmit and receive microwave signals, and the receiving antenna is of an array type in which a plurality of elements are arranged in parallel, In a multi-lane vehicle sensor that processes a signal for each lane obtained from an antenna in a signal processing unit to detect the presence or absence of a vehicle in each lane, calculate vehicle speed, etc., the signal received by each element of the receiving antenna is It is equipped with a distributor that distributes signals according to the number of lanes, and a plurality of phasers that delay the distributed signals by a predetermined phase so that directional characteristics corresponding to each lane can be obtained. A multi-lane vehicle sensor characterized in that a received signal for each lane is obtained with corresponding directional characteristics.