JPH06281732A - Communication system of moving object identifying device - Google Patents

Abstract

PURPOSE:To obtain such a communication system for moving object identifying devices that one interrogator can perform the procedures for performing communication by actuating a responder mounted on a high-speed moving object from intermittent operation. CONSTITUTION:An interrogator continuously transmits interrogating signals Q respectively composed of a plurality of frames and having the same content to a responder at preset prescribed frame intervals t12 for a period of time longer than the interval of the intermittent operation of the responder. The responder is provided with a timer counter which is reset and counts the receiving time of the signals Q whenever the signals Q are received from the interrogator for a prescribed period of time t23 and a control means which discriminates the punctuation between frames based on the count value of the timer counter when no signal is received from the interrogator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads the identification number of a transponder from an interrogator using a non-contact communication means such as radio waves, or transmits data to the transponder held in a moving body. The present invention relates to a communication system in a mobile body identification device for writing, for example, a system that manages operation by identifying a mobile body that moves at high speed such as a train, or a car that passes a toll road by identifying a car. It is used in a system that manages, other FA fields, logistics fields, and the like.

[0002]

2. Description of the Related Art FIG. 4 shows a schematic structure of a conventional moving body identifying apparatus. In this device, the interrogator 1 transmits the interrogation signal Q to the responder 2 by using non-contact communication means such as radio waves. Responder 2 receives this inquiry signal Q and returns response signal A including its own identification number. By receiving the response signal A, the interrogator 1 reads the identification number of the responder 2 in a contactless manner. Further, the data included in the interrogation signal Q is used to write the data from the interrogator 1 to the responder 2 in a contactless manner. In this type of wireless communication system, data may not be normally received in one communication due to the effects of multipath, interference waves, interference waves, etc. By performing communication multiple times, data errors and false alarms are prevented. , The method of increasing the reliability of the system is often used.

A technique for identifying a high-speed moving body such as a train using such a moving body identifying apparatus has been proposed.
FIG. 5 shows a configuration diagram of a conventional high-speed moving object identification device. In the figure, T is a train that becomes a high-speed moving body, 2a holds information such as a vehicle number, and a responder that normally operates intermittently to extend battery life, 1a activates a responder 2a that operates intermittently. An interrogator 1b for performing communication is provided for communicating with the responder 2a which is activated from the intermittent operation and is in the communication mode.

FIG. 6 shows a communication system in this high-speed moving body identifying apparatus. In the figure, Q is an inquiry signal transmitted from the interrogator to the responder, and A is a response signal returned from the responder to the interrogator. The train T holding the transponder 2a is going to pass in front of the interrogators 1a and 1b in sequence. Interrogator 1
A radio wave is constantly transmitted from a, and the responder 2a operating intermittently detects the radio wave from the interrogator 1a and shifts to the communication mode. Next, the transponder 2a that has moved to the communication mode receives the interrogation signal Q from the interrogator 1b, and according to the received command, the same content consisting of a plurality of frames at a predetermined frame interval t22 that is predetermined as shown in FIG. Response signal A of In the figure, COM is a command, ID is its own identification number, DT is data, and BCC is a check code.
The interrogator 1b includes a timer counter that is reset each time a signal from the transponder 2a is received for a predetermined length (for example, 1 byte) and counts the reception time. Is configured to determine the delimiter between the frames based on the timer counter value when the signal from is not received. As described above, the conventional interrogator enhances the reliability of communication by using the means for receiving the reply signal in which the frames of the same data are continuously transmitted and processing only the correct data (frame). .

Utilizing the moving body identifying apparatus as described above,
A system that mounts a responder on the train, communicates with an interrogator installed at a predetermined location along the track, and manages train operation by identifying the train. There has been proposed a system for managing a vehicle passing through a toll road by communicating with an interrogator installed near the vehicle and identifying the vehicle.

[0006]

However, in the conventional moving body identifying apparatus, as shown in FIG. 5, the transponder 2 is used.
Since a is constantly operating, it is necessary to provide an interrogator 1b for activation in addition to the interrogator 1a for communication. When the mobile identification device using radio waves is applied to the system as described above, if the system is configured using two interrogators, the activation interrogator 1a affects the exchange interrogator 1b. The influence of interference must be taken into consideration, and it is not preferable in terms of increased cost and reduced versatility.

The present invention has been made in view of the above points, and an object of the present invention is to carry out one procedure from intermittent operation of a transponder mounted on a high-speed moving body to activation and communication. Another object of the present invention is to provide a communication system of a mobile body identification device which can be carried out by the interrogator.

[0008]

According to the present invention, in order to solve the above problems, as shown in FIGS. 1 to 3, a transponder held by a mobile unit and assigned a unique identification number is provided. 2 and an interrogator 1 that communicates with the responder 2 using non-contact communication means such as radio waves. The interrogator 1 periodically transmits a command and an unmodulated signal to the responder 2 alternately. Then, when the responder 2 receives the command sent from the interrogator 1, the interrogator in the mobile unit identification device, which modulates the unmodulated signal from the interrogator 1 according to the content of the reply data and sends it back to the interrogator 1, The device 1 is provided with control means for continuously transmitting to the responder 2 the interrogation signal Q consisting of a plurality of frames having the same content for a time T1 longer than the intermittent operation interval of the responder 2 at a predetermined frame interval t12 which is predetermined. , The responder 2 is quality Predetermined signals Q from vessel 1 length min t
23 A timer counter that is reset each time it receives and counts the reception time, and a control means that determines the separation between frames based on the count value of the timer counter when the signal from the interrogator 1 is not received for a predetermined length or longer. And is provided.

[0009]

In the communication system of the present invention, since the interrogator 1 continuously transmits the interrogation signal Q of the same data to the transponder 2 for a time T1 longer than the intermittent operation interval of the transponder 2, like a high-speed moving body. Even if the transponder 2 is attached to an object having a high moving speed, the interrogator 2 can be activated and communicated with the transponder 2 by one interrogator. Further, since the same data (frame) is continuously returned several times from the responder 2 that receives the inquiry signal Q, the reliability of communication can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is an application of the present invention to identification of a train moving at high speed. In the figure, T is a train that moves at high speed, 2
Is a transponder mounted on the train, in which information such as a vehicle number necessary for operation management is written, and 1 is an interrogator for reading and writing data of the transponder 2 mounted on the train T in a contactless manner. . FIG. 2 is a timing chart during communication of this system. In the figure, RXCNT2 is a reception control signal of the transponder 2, TXCNT2 is a transmission control signal of the transponder 2, TXCNT1 is a transmission control signal of the interrogator 1, and RXCN.
T1 is a reception control signal of the interrogator 1. FIG. 1 shows a communication format of the inquiry signal Q and the response signal A. In the figure, COM is a command, BCC is a check code, and ID.
Is its own identification number, and DT is data.

In the present embodiment, the command content that can be designated as the command COM is the identification of the identification number of the responder 2 such as read or write, the frame length of the data read from the responder 2, and the identification number of the responder 2. With or without,
It includes the number of bytes of data written to the transponder 2, the reply interval, the number of reply frames, and the like. Finally check code BCC
Is added and the one frame is transmitted continuously for a predetermined number of times at a predetermined interval t12 for a time period of T1.
Is formed. Further, one frame of the response signal A transmitted from the transponder 2 is, as shown in FIG. 1, a command COM indicating the content of the response (the same command as the command of the inquiry signal Q), its own identification number ID, and its own RAM. Several bytes of data DT read from, and check code BCC
Composed of.

Now, when the transponder 2 mounted on the train T enters the communication area of the interrogator 1 at the timing of FIG. 2a, the same data is transmitted from the interrogator 1 at a frame interval t12 for several consecutive frames T1. The transponder 2 operating intermittently detects the signal and shifts from the intermittent operation to the communication mode. The transponder 2 that has shifted to the communication mode receives 1 of the interrogation signal Q transmitted from the interrogator 1.
By using a timer counter that is reset each time a byte is received and the reception time is counted from the reset time, it is possible to determine the frame delimiter of the interrogation signal. Then, one frame of the received question signal Q is demodulated and decoded, the question content is decoded, and the process returns.

The response signal A returned from the responder 2 has the same command COM as the command of the inquiry signal Q, the identification number ID, the read data DT, and the error check code B at the beginning.
The reply data content, the number of reply data bytes, the number of replies, the reply frame interval, etc. are set according to the communication format included in the information of the inquiry signal Q and are transmitted to the interrogator 1.

On the side receiving the response signal A, first, one byte having the same numerical value as the command located at the beginning of one frame of the inquiry signal Q is found, and then the found one byte is located at the beginning of the reply frame. It is determined whether it is a command to execute or 1-byte data in the read data DT. As the determination method, a timer counter that counts the length of the signal is prepared like the responder 2, and the timer counter is reset every time 1 byte of normal data is received, and the timer counter becomes 1 byte or more in length. Check location, that is, between frames.
If the timer counter has a length of 1 byte or more, the data can be regarded as a command at the beginning of a new frame.

By the method as described above, the interrogator 1 can fetch and decode each frame into the reception buffer and obtain the decoded contents, that is, the read data DT of the responder 2. Since the interrogator 1 processes only the correctly received data from the received several frames, the reliability of communication can be improved.

[0016]

According to the communication system of the present invention, since the interrogator transmits the interrogation signal continuously for a predetermined time longer than the intermittent operation interval of the transponder, the interrogator operating intermittently operates. Startup and communication can be performed stably with a single interrogator in a short time. Therefore, even when identifying a high-speed moving object, it is not necessary to provide an interrogator for activating a responder, in addition to an interrogator for communication, and the interrogation for activation does not interfere with the communication interrogator. Not only can the introduction cost be reduced, but the versatility can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a communication format according to an embodiment of the present invention.

FIG. 2 is a timing chart showing a transmission / reception operation of an embodiment of the present invention.

FIG. 3 is a system configuration diagram showing an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional moving body identification device.

FIG. 5 is a system configuration diagram showing a conventional example.

FIG. 6 is an explanatory diagram showing a communication format in a conventional example.

[Explanation of symbols]

 Q Question signal A Response signal 1 Interrogator 2 Responder T Train

Claims (1)

[Claims] 1. An interrogator, which comprises a transponder that is held in a mobile unit and is assigned a unique identification number, and an interrogator that communicates with the transponder using non-contact communication means such as radio waves. Periodically sends a command and an unmodulated signal alternately to the responder, and when the responder receives the command sent from the interrogator, the responder responds to the unmodulated signal from the interrogator according to the contents of the reply data according to the command. In a mobile unit identification device that modulates and returns to an interrogator, the interrogator includes first control means for continuously transmitting interrogation signals of the same content consisting of a plurality of frames to a responder at a predetermined frame interval. The transponder is reset each time it receives a signal from the interrogator for a predetermined length and counts the reception time, and the signal from the interrogator is not received for a predetermined length or longer. And a second control means for determining a division between frames based on the count value of the timer counter when the mobile body identification device is in communication.