JP2007170867A - In-vehicle clock synchronization system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-vehicle clock synchronization system capable of synchronizing various clocks mounted in a car with the time of the most precise clock among the clocks. <P>SOLUTION: In the in-car clock synchronization system for synchronizing the times of two or more car devices each of which is disposed in the car and has a clock function, the car device is connected to a communication line 2 of a network, by which accuracy information and time information of the clocks are exchanged, and a CPU 100 is equipped with a discriminating section 102 for discriminating the most precise clock; a synchronization section 105 for executing synchronization with the time of the clock discriminated by the discriminating section 102; and a transmitting/receiving section 101 which connects to the communication line 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of an in-vehicle clock synchronization system that synchronizes the time of a plurality of vehicle devices having a clock function installed in a vehicle.

A predetermined information processing device among a plurality of information processing devices connected to the sub-network is selected as a reference information processing device for time adjustment, and a time recorded by each of the plurality of information processing devices is set as a time recorded by the reference information processing device. The time information is synchronized by matching (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2005-071082 (page 2-12, full view)

  Conventionally, however, accurate synchronization cannot be obtained in a vehicle constituted by various timepiece devices.

  The present invention has been made paying attention to the above-mentioned problems, and its object is to synchronize other timepieces with the time of the most accurate timepiece in various timepiece devices mounted on the vehicle. An object of the present invention is to provide a synchronization system for an in-vehicle clock.

  In order to achieve the above object, according to the first aspect of the present invention, in a synchronization system for an in-car clock that synchronizes the time of a plurality of vehicle devices having a clock function installed in a vehicle, the accuracy of the clock between the vehicle devices is achieved. Network means for exchanging information and time information, determination means for determining the accuracy of the accuracy information, and synchronization means for synchronizing with the time of the clock determined by the determination means, wherein the determination means is When the information of the accuracy equal to or higher than the accuracy information of the own timepiece is received, the synchronizing means is operated and the received accuracy information is stored as the accuracy information of the own timepiece.

  Therefore, according to the present invention, it is possible to synchronize other timepieces with the time of the most accurate timepiece in various timepiece devices mounted on the vehicle.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment for realizing a synchronous system for an internal timepiece according to the present invention will be described below based on a first embodiment corresponding to the inventions according to claims 1 and 2.

First, the configuration will be described.
FIG. 1 is a schematic diagram of a synchronization system for an internal timepiece according to a first embodiment.
In the synchronous system for an in-car clock according to the first embodiment, a network 1 is formed by a plurality of vehicle devices having a clock function. Take CAN as an example of a network.
The network 1 is configured by connecting a radio clock device 3, a navigation device 4, an ETC device 5, a data logger device 6, and an audio device 7 through a communication line 2.
In the case of CAN, the communication line 2 is a twisted pair line based on the CSMA / CD communication method.
The radio clock device 3 displays a more accurate time by receiving radio waves of time information, and includes a CPU 31 that performs network transmission / reception and synchronization processing, and a clock unit 32.

The navigation device 4 obtains information by GPS or the like, displays a map and a vehicle position, guides to a destination, and the like, and includes a CPU 41 that performs network transmission / reception and synchronization processing, and a clock unit 42. .
The ETC device 5 automatically pays road charges and the like by communication with a passing ETC gate or the like, and includes a CPU 51 that performs network transmission / reception and synchronization processing, and a clock unit 52.

The data logger device 6 processes and stores the detection results of sensors and the like provided in the vehicle, and transmits them to the vehicle device and the like via the network 1 as necessary, and performs network transmission / reception and synchronization processing. A CPU 61 and a clock unit 62 are provided.
The audio device 7 performs reproduction of music stored in a medium, reproduction of radio, and the like, and includes a CPU 71 that performs network transmission / reception and synchronization processing, and a clock unit 72.

The information exchanged in the network 1 includes transmission data 200 as shown in FIG.
The transmission data 200 includes synchronization signal information 201 and clock accuracy information. Furthermore, an ID code assigned to identify the device is included (not shown).
The synchronization signal information 201 includes time information and a synchronization signal for synchronization.
The clock accuracy information 202 is information indicating the accuracy of the clock device.

FIG. 2 is a block diagram of a portion related to the clock function of the vehicle device of the synchronization system for the internal clock of the first embodiment.
The contents of the block diagram may be either software or hardware.
Further, as described above, the CPU included in each device will be described as CPU 100, and the clock unit will be described as clock unit 110.
The CPU 100 includes a transmission / reception unit 101, a determination unit 102, a unique information storage unit 103, an accuracy information storage unit 104, a synchronization unit 105, and a transmission data generation unit 106.

The transmission / reception unit 101 performs transmission / reception by input / output to / from the communication line 2 and conversion between a data signal used in the CPU 100 and a signal used in the communication line 2. The reception data is output to the determination unit 102, and the transmission data from the transmission data generation unit 106 is converted and transmitted to the communication line 2.

The determination unit 102 uses the received synchronization signal information 201, clock accuracy information 202, clock specific time information and accuracy information from the unique information storage unit 103, time information and accuracy information from the accuracy information storage unit 104, Is synchronized with the received data, and in the case of synchronization, an output instructing the synchronization unit 105 is performed. In addition, the latest accuracy information based on the current determination is output to the transmission data generation unit 106.
The unique information storage unit 103 stores time information and accuracy information that the clock 110 originally has, and outputs the information to the determination unit 102. This accuracy information starts when IGN is turned on.

The accuracy information storage unit 104 stores accuracy information for synchronization with high accuracy, and outputs the accuracy information to the determination unit 102.
The synchronization unit 105 synchronizes the clock unit 110 with the received synchronization signal and time information.
The transmission data generation unit 106 generates transmission data from the current clock synchronization signal information and accuracy information, and outputs the transmission data to the transmission / reception unit 101.

Next, the operation will be described.
[About the watch in the car]
The car clock will be described.
When a plurality of watches are installed in a car, the time displayed on each clock may shift with time, and the user may feel uncomfortable. To prevent this, use a network in the car to generate clock synchronization signals and synchronize the clocks with each other, and fixedly determine that the most accurate clocks emit synchronization signals. This causes the following problems.

Since this high-precision timepiece is expensive, there are cases where it is not equipped with the vehicle, and there is a problem that the synchronization system does not function in such a vehicle.
On the other hand, if it is determined that the clocks mounted on all the set vehicles emit a synchronization signal, there arises a problem that a clock with high accuracy is synchronized with a clock with low accuracy.
The first embodiment solves these problems.

[Clock synchronization processing]
FIG. 3 is a flowchart showing the flow of the synchronization process executed by the CPU and the clock unit of each device of the synchronous system for the clock in the automobile according to the first embodiment. Each step will be described below.

  In step S1, the accuracy information of its own clock is stored, and the process proceeds to step S2.

  In step S2, it is determined whether or not it is a synchronization signal transmission time. If it is the synchronization signal transmission time, the process proceeds to step S3, and if it is not the synchronization signal transmission time, the process proceeds to step S4.

  In step S3, a synchronization signal is transmitted, and the process proceeds to step S4.

  In step S4, it is determined whether or not a synchronization signal has been received from another clock. If received, the process proceeds to step S5, and if not received, the process returns to step S2.

  In step S5, it is determined whether or not the received accuracy information is equal to or higher than the stored accuracy information. If it is equal or higher, the process proceeds to step S6, and if it is lower, the process returns to step S2.

  In step S6, the own clock time is corrected in accordance with the synchronization signal, and the process proceeds to step S7.

  In step S7, the received accuracy information is stored.

[Action to synchronize with a highly accurate clock corresponding to various vehicle configurations]
In the first embodiment, as shown in FIG. 1, the radio clock device 3 has the best timepiece accuracy, followed by the navigation device 4, the ETC device 5, the data logger device 6, and the audio device 7 in order. ing.
In this configuration, even if a different device is inserted, there may be a device that comes out of this.
When the IGN power supply is turned on, an ID code is assigned in advance according to the priority order, or dynamic assignment is performed, and the network 1 is configured by devices currently connected to the communication line 2.

  In this state, each device transmits the transmission data 200 by the process of step S2. For example, when the ETC device 5 receives the transmission data of the navigation device 4 (step S4), the ETC device 5 determines that the accuracy is higher than its own accuracy (step S5), and synchronizes the time and time of the navigation device 4 with the synchronization signal (step S6). ). At this time, accuracy information of the navigation device 4 is stored (step S7).

Thereby, in the next comparison, even if the transmission data 200 of the data logger device 6 or the transmission data 200 of the audio device 7 is received, it is not synchronized with a clock lower than the accuracy information of the navigation device 4 storing its own clock. . In other words, data that is less accurate than itself is ignored.
On the other hand, when the transmission data of the radio clock device 3 is received, the data is higher in accuracy than the accuracy information of the navigation device 4 stored by itself, and therefore the radio clock device 3 is synchronized with the time of the radio clock device 3. The accuracy information is stored.

After that, if there is transmission data from the radio timepiece apparatus with the same accuracy as determined in step S5, the time synchronized with the data is corrected.
That is, the navigation device 4, the ETC device 5, the data logger device 6, and the audio device 7 come to synchronize with a highly accurate clock one after another, and as a result, the most accurate timepiece in the vehicle configuration. In other words, its own clock is synchronized with the radio wave clock device 3.

  In the first embodiment, when the radio timepiece device 3 is not provided as the device configuration of the vehicle, other devices are synchronized with the time of the navigation device 4 having the next highest accuracy after the radio timepiece device 3. Therefore, even if the most accurate device is not included in the network configuration without causing any problems as a system, there is no device that matches the clock with a lower accuracy than itself, and the watch with the highest accuracy among the configurations. Can be unified.

  Thereby, it is possible to give the user the comfort that comes from the unity of the clock display of the vehicle, and to improve the reliability of the clock accuracy.

  Furthermore, in the first embodiment, when a device having the most accurate timepiece has some sort of failure, an error is determined in the network 1 and is excluded from the network. Will be synchronized. Therefore, even if there is an abnormality or the like, it is possible to display the clock with the highest possible accuracy for the user.

Here, the accuracy information will be described.
The accuracy information may be information indicating the accuracy of the timepiece, and may be, for example, data indicating error information with respect to a specified time, or may be indicated by a previously ranked code.
Table 1 shows a pre-ranked code and its contents.

  In the display 1, the accuracy information is divided into four ranks of 10, 20, 30, and 40. The code 10 is always synchronized with an external accurate clock such as a radio clock, and the code 20 is sometimes synchronized with an external accurate clock such as a radio clock as an example. The code 30 may be synchronized with an external clock such as ETC, and the code 40 is operated by its own crystal oscillation such as audio. In this way, ranking may be performed in advance according to the synchronization method, and the codes may be displayed, so that the determination load can be reduced and the determination can be made easily.

Next, the effect will be described.
The effects listed below can be obtained in the synchronous system for the internal clock of the first embodiment.

  (1) In an automobile clock synchronization system that synchronizes the time of a plurality of vehicle devices having a clock function installed in a vehicle, a network 1 for exchanging clock accuracy information and time information between the vehicle devices, and accuracy Since the CPU 100 includes a determination unit 102 that determines the accuracy of information and a synchronization unit 105 of the CPU 100 that synchronizes with the time of the clock determined by the determination unit 102, Other clocks can be synchronized with the time of the clock with high accuracy. As a result, it is possible to give the user the comfort that comes from the unity of the clock display of the vehicle, and to improve the reliability of the clock accuracy.

  In addition, when the determination unit 102 receives information with accuracy equal to or higher than the accuracy information of the own clock, the determination unit 102 synchronizes with the synchronization unit 105 and stores the accuracy information in the accuracy information storage unit 104 as the accuracy information of the own clock. In order to memorize, it is synchronized with higher accuracy than itself, and it is repeated to update its own data to a higher one, and in various timepieces equipped on the vehicle, the time of the clock with the highest accuracy is obtained. Other clocks can be synchronized.

  As mentioned above, although the synchronous system of the internal clock of the present invention has been described based on the first embodiment, the specific configuration is not limited to these embodiments, and it relates to each claim of the claims. Design changes and additions are allowed without departing from the scope of the invention.

In the first embodiment, the network configuration is a radio timepiece device, a navigation device, an ETC device, a data logger device, and an audio device, but other devices may be added. It may be configured by several or may be configured by other devices.
If the vehicle adopts CAN as the network, it can be implemented in the vehicle at a reduced cost, simply by increasing communication messages.

  The network is not limited to CAN. The network may be configured by a dedicated communication line. Moreover, the network in a vehicle by a system different from CAN may be used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. It is a block diagram of the part regarding the timepiece function of the vehicle apparatus of the synchronizing system of the timepiece in a car of Example 1. FIG. 3 is a flowchart illustrating a flow of synchronization processing executed by a CPU and a clock unit of each device of the synchronization system of the in-car clock according to the first embodiment.

Explanation of symbols

1 Network 2 Communication Line 3 Radio Clock Device 31 CPU
32 Clock unit 4 Navigation device 41 CPU
42 Clock part 5 ETC device 51 CPU
52 Clock unit 6 Data logger device 61 CPU
62 Clock unit 7 Audio device 71 CPU
72 Clock unit 100 CPU
101 Transmission / Reception Unit 102 Discrimination Unit 103 Specific Information Storage Unit 104 Accuracy Information Storage Unit 105 Synchronization Unit 106 Transmission Data Generation Unit 110 Clock Unit 200 Transmission Data 201 Synchronization Signal Information 202 Accuracy Information

Claims (1)

In a synchronization system for an in-car clock that synchronizes the times of a plurality of vehicle devices having a clock function installed in a vehicle,
Network means for exchanging clock accuracy information and time information between the vehicle devices;
A discriminating means for discriminating the accuracy of the accuracy information;
Synchronization means for synchronizing with the time of the clock determined by the determination means;
With
The discrimination means includes
If you receive information with accuracy equal to or higher than the accuracy information of your watch,
Activating the synchronization means and storing the received accuracy information as accuracy information of the own timepiece,
A system for synchronizing a car internal clock.

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