JPS61163499A - Road information transmitter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention transmits digital road information signals by radio waves from a transmitting device installed on the roadside to a traveling vehicle, and receives the information by a receiving device installed on the vehicle side. The present invention relates to a road information transmission device that receives road information.

[Prior Art] This type of road information transmission device uses radio wave reception to transmit specific information that is valid within a narrow area (for example, information that there is a curve) to vehicles, and to prevent radio wave interference. The area is a narrow area.

For this reason, the reception time from the road information transmission device differs depending on the vehicle speed, and when driving at high speed, the signal cannot be received a sufficient number of times, increasing the probability that errors will occur in the received digital data. Conversely, when driving at low speeds, more signals than necessary will be received.

[Problems to be Solved by the Invention] According to the present invention, the roadside transmitting device transmits necessary and sufficient road information to the vehicle, regardless of the vehicle speed of passing vehicles, and the vehicle-side receiving device receives the information and provides accurate source information. An object of the present invention is to obtain a road information transmission device that can discriminate information.

[Means for Solving the Problems] A road information transmission device according to the present invention includes a roadside transmission device that is installed on the roadside and transmits a road information signal to vehicles existing within a predetermined area, and a roadside transmission device that is installed in the vehicle and transmits the road information signal. a vehicle-side receiving device that receives a signal and discriminates the signal; the road-side transmitting device includes a vehicle sensing device that detects the presence and vehicle speed of a passing vehicle; and a road information signal transmitting device according to the detected vehicle speed. and a road information signal transmission means that transmits a predetermined number of road information signals at intervals of the road information signal transmission interval.
The device includes a road information signal receiving means for receiving the transmitted road information signal, and a correct signal discriminating means for discriminating the correct road information signal from the plurality of received road information signals by a majority vote principle. .

[Operation] When the vehicle sensing means detects the vehicle speed of a passing vehicle, the road information signal transmission interval calculation means calculates a road information signal transmission interval according to the vehicle speed, and the road information signal transmission means calculates a road information signal transmission interval at this interval. transmits road information signals.

Therefore, the vehicle-side receiving device can receive necessary and sufficient road information signals.

The correct signal discriminating means of the vehicle-side receiving device discriminates the correct road information signal from the plurality of road information signals based on the principle of majority voting.

[Example] An example of the road information transmission device according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, an ultrasonic transducer 12 is provided above the road side of the road 10, and uses ultrasonic waves to determine the vehicle speed V of the vehicle 14.
This detection signal is input to the Doppler signal output circuit 16, and the Doppler frequency signal from the Doppler signal output circuit 16 is input to the transmitter @20 attached to the road sign 18. ing.

Next, the details of the above configuration will be explained according to FIG. A high frequency signal of frequency f is transmitted from the transmitting port 18123 of the Doppler signal output circuit 16 to the transmitter 24 of the ultrasonic transducer 12.
It is output to. Ultrasonic waves are emitted from the transmitter 24, reflected by the vehicle 14 traveling at a vehicle speed V, and received by the receiver 25 of the ultrasonic transducer 12. This received @frequency f signal and the frequency f from the transmitting circuit 23
The Q signal is input to the mixing circuit 26, and the sum and difference signals of f and f are output from the mixing circuit 26.

From the low-pass filter 27, the frequency of the difference between f and fo,
That is, a signal with a Doppler frequency Δf is output, which is then input to the counter 28, where the number of waves within a unit time is counted and converted into a digital signal. This Doppler frequency digital signal is input to a control circuit 29 comprised of a microcomputer. If Δf is not zero, it means that the presence of a running vehicle has been confirmed, and the control circuit 29 transmits the pre-coded sign signal to the encoder 5 after performing calculations to be described later.
4 and outputs it to the modulation circuit 58. On the other hand, the carrier wave is output from the excavation circuit 56,
The signal is input to a modulation circuit 58 via a buffer amplifier 57. The modulation circuit 58 performs, for example, FSX modulation on this carrier wave based on a signal from the control circuit 52. The signal from the modulation diagram 1185B is multiplied by a multiplier circuit 60, and then its power is amplified by a power amplification circuit 62, so that a beacon signal is outputted from the antenna 22 in the form of radio waves.

Next, the vehicle-side receiver 5 provided in the vehicle according to FIG.
Explain 0. This vehicle-side receiver 41150 is configured to capture a sign signal from the roadside transceiver 18 or the roadside transceiver 20 with an antenna 30.The antenna 30 has directivity, and the signal is received in a direction slightly to the left of the front of the vehicle. It is attached to the vehicle with the direction facing.

The label signal is input to the high frequency amplification circuit 32 and amplified. The output signal from the high frequency amplification circuit 32 and the constant frequency signal from the local oscillator 33 are input to the mixer 34 and mixed, and a signal of the sum or difference of circular frequencies is output to the band pass filter 35. The band pass filter 35 passes only this difference signal (beat signal), which is then amplified by the intermediate frequency amplification circuit 36 and then the limiter 3.
7 limits the amplitude and removes noise.0 Next, the demodulation circuit 3B demodulates the original signal, which is sent to the control circuit 4.
Input to 0. The control circuit 40 causes the display 42 to display a sign in response to this input signal.The display 42 is constituted by a CRT, and is capable of displaying the same sign as the detected road sign. When the beacon signal "Sound the horn" is input to the control circuit 40, a horn is output from the speaker 44. Further, a signal from a headlamp switch 46 is input to the control circuit 40, so that the headlamp 48 flashes (passing) when there is an oncoming vehicle at night. Furthermore, a signal from a vehicle speed sensor 50 is input to the control circuit 40, and the input signal from the demodulation circuit 38 is held for a time inversely proportional to the vehicle speed, and the display 42 is displayed for only this time.
, speaker 44. A signal is output to the headlamp 48.

Next, the operation of this embodiment configured as described above will be explained with reference to the flowcharts shown in FIGS. 5 and 6.

FIG. 5 shows a control flowchart of the control circuit 29, in which in step 100 the Doppler frequency Δf is
Determine the presence or absence of. In the case of ΔfMo, the passing vehicle 14 does not exist below the ultrasonic transducer 12, and when Δf is not 0, the passing vehicle 14 exists below the ultrasonic transducer 12, and the ultrasonic transducer 12 The device 12 calculates the vehicle speed V and the road information signal transmission interval m2 (see FIG. 4).

In step 102, θ1 is the ultrasonic reflection angle, 02 is the ultrasonic incidence angle, and C is the speed of sound, as shown in FIG. Also L
As shown in Figure 1, the radio waves emitted from the vehicle 1
4 is the distance of the receivable area. Further, ml is the transmission time of the road information signal as shown in FIG. @ is the margin time, and N is the number of times the road information signal is transmitted. 0 Then, a start signal S for starting the circuits other than the control circuit 29 of the transmitter 20 shown in FIG. 2 is output (step 104).
．． Figure 4 S) 0 Then set the value of N to 0 Step 106
), set the value of T to O (step 108), then increment the value of T until the value of T is equal to m2 (steps 110 and 112), where the time unit of m2 is the same as the processing of steps 110 and 112. 0 which is the time, then the code of the beacon signal is read from the encoder 54 and the modulation circuit 5
8 (step 114), and repeats the processing of steps 108 to 114 N times (step 11).
6).

In this way, N road information signals can be output to the vehicle regardless of the vehicle speed.

Next, the control circuit 2 of the transmitter 20 outputs a stop signal E.
Turn off the circuits other than 9 (step 118, Fig. 4E)
, return to step 100. Therefore, since the road information signal is output only when the vehicle passes below the ultrasonic transducer 12, the power consumption of the transmitter 20 can be saved. Repeat the process.

Next, the majority decision principle for determining correct data from the data input to the control circuit 40 will be explained according to FIG. In step 200, the first bit data D (1, J) among m bits is output from the demodulation circuit 38 for the first time of repetition.
, I takes a value from 1 to n (n≦N), and J takes a bond from 1 to m. That is, read the m-bit indicator data n times as 0, then set the value of J to 1 in step 2.
02), the value of l is set to 1.0 (J), the value of 011 (J) is set to 0 (step 204), and then D(I, J
) is 1 (step 206), increment the value of O(J) (step 208), otherwise increment the value of 1 (J) (step 208).
i0), the above process is repeated n times (step 212.21
4), then if the value of 0 (J) is less than or equal to the value of 1 (J), set the value of DD (J) to 1 (step 218)
, otherwise, set the value of DD (J) to 0 (step 220), repeat the process from step 204 to step 220 m times (step 222, 224), and then determine the value obtained by such majority voting principle. Data DD
(J) is decoded (step 226), and outputted to the display 42, and depending on the data, the speaker 44 sounds the horn or the headlamp flashes (step 228).

In this way, accurate sign signals can be obtained regardless of vehicle speed.

Note that DD (J) may include parity pits, in which case parity check is performed between steps 222 and 223, and step 226 is performed only when there is no error.
Move to.

Furthermore, the vehicle sensing means is not limited to one that uses ultrasonic waves, but may also use radio waves or light.

Furthermore, road information is not limited to sign signals.

[Effects of the Invention] In the road information transmission device according to the present invention, the roadside transmission device detects the vehicle speed of a passing vehicle, calculates a road information signal transmission interval according to the vehicle speed, and transmits a predetermined number of road information signals at this interval. The receiving device on the vehicle side receives the plurality of road information signals and determines the correct road information signal based on the principle of majority voting, so it receives accurate road information regardless of the vehicle speed of passing vehicles. It has the excellent effect of being able to

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing an embodiment of the road information transmission device according to the present invention, FIG. 2 is a block diagram showing the configuration of the roadside transmitting device, and FIG. 3 is a block diagram showing the configuration of the vehicle side receiving device. FIG. 4 is a waveform diagram illustrating the road information transmission time and transmission interval, FIG. 5 is a control flowchart for transmitting road information, and FIG. 6 is a flowchart showing a method for obtaining accurate road information using the majority vote principle. 12-φ fist ultrasonic transducer. 16... Doppler signal output circuit, 20... Roadside transmitter. 50 fists...vehicle side receiver. Agent Patent Attorney Atsushi Nakajima Figure 5 Figure 6

Claims (2)

[Claims] (1) It has a roadside transmitter that is installed on the roadside and transmits a road information signal to vehicles within a predetermined area, and a vehicle side receiver that is installed in the vehicle and receives the road information signal and discriminates the signal. The roadside transmitting device includes a vehicle sensing means for detecting the presence and vehicle speed of a passing vehicle, a road information signal transmission interval calculation means for calculating a road information signal transmission interval according to the detected vehicle speed, and a road information signal transmission interval calculation means for calculating a road information signal transmission interval according to the detected vehicle speed. road information signal transmitting means for transmitting a predetermined number of road information signals at transmission intervals; the vehicle-side receiving device includes road information signal receiving means for receiving the transmitted road information signals; 1. A road information transmitting device comprising: correct signal discriminating means for discriminating a correct road information signal from a plurality of road information signals based on a majority vote principle. (2) The roadside transmitting device starts emitting radio waves when the vehicle sensing means detects the presence of a passing vehicle, and stops emitting radio waves after transmitting N road information signals.
The road information transmission device described in Section 1.