JP5455799B2 - In-vehicle recording device - Google Patents

Description

  The present invention relates to a time correction method for an in-vehicle clock mounted on an in-vehicle recording device such as a drive recorder or a digital tachograph.

  In-vehicle recording devices such as drive recorders and digital tachographs that record histories of vehicle operations have been widely used in recent years, mainly by carriers. The in-vehicle recording device incorporates a speed sensor, a GPS (Global Positioning System) module, a card type recording medium, and the like, and records an operation history such as a vehicle speed, a travel distance, and a current position.

  The in-vehicle recording device records the operation history in chronological order while referring to the time of the in-vehicle clock equipped in the in-vehicle device. However, since the in-vehicle clock inevitably generates a certain error, recently the position information acquired by the GPS module A method of correcting the time of an in-vehicle clock using information related to the current time included is widely adopted (see, for example, Patent Document 1).

  However, if the time of the in-vehicle clock is corrected while the operation history is being recorded (during work), the consistency of the recorded data is lost. Therefore, the correction of the time is performed when the operation history is not recorded. It is set to be executed before the business start or after the business end (specifically, for example, when the card-type recording medium is detached from the in-vehicle recording device).

Japanese Patent Laid-Open No. 11-250391, page 4 to page 9 FIG.

  However, the above-described conventional in-vehicle recording apparatus has a problem that the vehicle is often in a place where it is difficult to receive GPS information before the start of work or after the end of work.

  For example, in the case of a transportation company that stores a vehicle in a large garage or the like until the day's work ends and the driver removes the card-type recording medium and resumes work the next day, the indoor GPS If the radio wave reception status is poor, the in-vehicle recording device cannot correct the time using GPS information. On the other hand, after the driver inserts the card-type recording medium into the in-vehicle recording device and starts the day's work and leaves the garage, the time adjustment of the in-vehicle clock is not performed for the above-described reason. For this reason, there is a situation in which the time correction of the in-vehicle clock is not performed at all for vehicles that depart from the same garage every day and return to the same garage after the end of work.

  As described above, in the conventional in-vehicle recording device, when the vehicle cannot receive GPS radio waves when the operation history is not recorded (standby) for a long period of time, the operation operation is completed (for example, during the daytime) For example, the time of the in-vehicle clock cannot be corrected even at night, and there is a problem that the error of the in-vehicle clock gradually increases even if the time adjustment function is provided.

The present invention has been made in view of the circumstances described above, and its purpose is to approximate the time of the in-vehicle clock even when GPS information cannot be acquired in a time zone in which the time of the in-vehicle clock can be corrected. modified to provide a vehicle recording equipment that can prevent the spread of the deviation of the watch due to the accumulation of errors.

In order to achieve the above-described object, the in-vehicle recording apparatus according to the present invention is characterized by the following (1).
(1) On-board watch,
Standard time information acquisition means that enables acquisition of information related to the standard time in a predetermined time zone ,
Time correction means for correcting the time of the in-vehicle clock based on the information related to the standard time acquired by the standard time information acquisition means;
A time counting means for performing timer counting;
An in-vehicle recording apparatus comprising:
The time measuring means starts a timer count starting from the standard time acquired most recently,
When the standard time information acquisition unit cannot acquire information related to the standard time in a time zone in which the time of the in-vehicle clock can be corrected, the time correction unit includes the timer count value counted by the timer by the timer unit. Correct the time of the in-vehicle clock with the internal reference time added to the standard time,
about.

  According to the in-vehicle recording device of (1) above, even when the standard time information cannot be acquired in a time zone in which the time of the in-vehicle clock can be corrected, it is calculated by a timer count starting from the most recently acquired standard time. Since the time of the in-vehicle clock is approximately corrected with the internal reference time, it is possible to prevent the time deviation from being enlarged due to the accumulation of errors.

An in-vehicle recording equipment of the present invention, even if it is not possible to obtain the standard time information in the time zone that can be time correction of the in-vehicle clock, correct the time of the vehicle clock approximately, watch due to the accumulation of errors An increase in the deviation can be prevented.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

It is a schematic diagram which shows schematic structure of the vehicle-mounted recording apparatus in embodiment of this invention. It is a flowchart which shows the timepiece correction | amendment operation | movement procedure of the vehicle-mounted recording apparatus in embodiment of this invention.

  Hereinafter, an in-vehicle recording apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a schematic configuration of an in-vehicle recording apparatus according to an embodiment of the present invention. The in-vehicle recording device 100 according to the present embodiment mainly includes a CPU 10, a GPS module 20, a received GPS time data recording unit 31, a time data recording unit 32, a data processing unit 40, a card interface 41, an in-vehicle clock 50, and the like. The

  The CPU 10 is a control unit that performs overall control of all operations of the in-vehicle recording apparatus 100, and performs control such as a time correction operation described later. Further, the CPU 10 has an internal clock (not shown), and also serves as a time measuring means for performing timer counting.

  The GPS module 20 receives radio waves from GPS satellites and acquires GPS data. The GPS data is positioning information, which includes current time (standard time) information, and the time information is recorded in the reception GPS time data recording unit 31. The GPS module 20 in the in-vehicle recording device 100 of the present embodiment plays a role as standard time information acquisition means.

  The reception GPS time data recording unit 31 is a buffer for temporarily recording current time (standard time) information included in the GPS data. The time data recording unit 32 is a buffer for temporarily recording time information counted by a timer from the reception GPS time recorded in the reception GPS time data recording unit 31. Both the reception GPS time data recording unit 31 and the time measurement data recording unit 32 are configured by SRAM or the like.

  When the CPU 10 acquires GPS data via the GPS module 20, it records the current time information as received GPS time data (Rt) in the received GPS time data recording unit 31, and at the same time, records it in the timekeeping data recording unit 32. The time (Gt) is replaced with the received GPS time data (Rt).

  Thereafter, the CPU 10 starts counting up at a predetermined cycle (for example, every 1 second) starting from Gt replaced with Rt (n = n + 1). The internal reference time (Gt = Gt + 1) updated by adding the count value is recorded in the time data recording unit 32 at any time.

  For example, if the received current time data is 15:26:34 (15:26:34), “15:26:34” is recorded in the received GPS time data recording unit 31, and at the same time, The clock starts counting up with a period of 1 second (n = n + 1). For example, when the number of count-ups is 3 (n = 3), the internal reference time (Gt) recorded in the time measurement data recording unit 32 is “15:26:37”.

  The data processing unit 40 stores all information (speed, mileage, current position, engine speed, recorded video, etc., some of which are not shown) collected by the in-vehicle recording device 100 as an operation history. Data processing for recording in The processed data is recorded in the memory card 200 via the card interface 41.

  In the in-vehicle recording device according to the embodiment of the present invention, when the memory card 200 is attached to the in-vehicle device (main body), it is determined that the business is in progress (recording operation history) and data is written as needed. Therefore, as will be described later, the time correction of the in-vehicle clock 50 is not performed while the memory card 200 is mounted on the main body. This is because if the time is corrected while the operation history is recorded, the consistency of the time data of the operation history is impaired.

  The in-vehicle timepiece 50 is a timepiece provided in the in-vehicle recording device 100 and provides current time information to the driver. The CPU 10 corrects the time of the in-vehicle clock 50 by a time correction operation described later.

  Next, the clock correction operation of the in-vehicle recording apparatus having the above configuration will be described.

  FIG. 2 is a flowchart showing a clock correction operation procedure of the in-vehicle recording device according to the embodiment of the present invention. First, the CPU 10 determines whether or not the memory card 200 for recording the operation history is inserted into the in-vehicle device (in-vehicle recording device 100) via the card interface 41 (step S101).

  When the memory card 200 is inserted, the CPU 10 determines that the operation history is being recorded, and then determines whether or not the GPS module 20 can receive GPS radio waves (step S102). If the vehicle can receive GPS radio waves (Yes in step S102), the CPU 10 receives position information via the GPS module 20, and receives current time information (received GPS time data: Rt) included therein. It memorize | stores in the time data memory | storage part 31 (step S103).

  From the determination result of step S101, since the operation history is currently being recorded and the time of the in-vehicle clock 50 cannot be updated, the CPU 10 starts from the internal reference time (Gt) replaced with the reception GPS time (Rt). The timer count to be started is started (step S104). The internal reference time (Gt = Gt + 1) obtained by adding the timer count value (n = n + 1) is stored in the time data recording unit 32.

  Next, the CPU 10 determines again whether or not the memory card 200 is being inserted (step S107). If it is being inserted (recording the operation history), the process returns to step S102. If GPS radio waves can be received, the procedure from step S103 to step S104 is repeated.

  On the other hand, if the vehicle cannot receive GPS radio waves in step S102, the CPU 10 continues the timer count starting from the latest Gt (step S105).

  By the above procedure, the latest standard time (current time at the time of reception) when GPS radio waves can be received is recorded in the reception GPS time data storage unit 31, and the latest standard time is recorded in the timekeeping data recording unit 32. Is recorded as the current time (Gt: internal reference time data) counted by the timer.

  Among the procedures described above, the procedure that flows from step S102 to steps S103 and S104 corresponds to, for example, the operation of the in-vehicle recording device when the vehicle in operation is traveling outdoors where GPS radio waves can be received. Since the operation history is being recorded, the time of the in-vehicle clock 50 cannot be updated even if GPS radio waves are received. However, as long as GPS radio waves can be received, Gt is updated with the latest Rt, and the updated Gt is updated. A timer count is started as a starting point. When the latest Rt is updated within 24 hours, for example, the error that occurs in the timer count based on the internal clock of the CPU 10 is very small, so the internal reference time updated by adding the timer count value Can be regarded as an approximate “standard time”.

  On the other hand, among the above procedures, the procedure that flows from step S102 to step S105 is, for example, the operation of the in-vehicle recording device when the vehicle in operation is traveling in an area where the reception state of the tunnel or GPS radio wave is poor. Equivalent to. Even if GPS radio waves cannot be received, the timer count continues from the most recent standard time, so the internal reference time updated by adding the timer count value is approximated by the approximate “standard time” as above. ".

  Next, when it is determined in step S107 that the memory card 200 is removed from the in-vehicle device (No in step S107), the CPU 10 determines that the operation work (recording of operation history) is completed, The operation proceeds to the time correction operation of the in-vehicle clock 50.

  First, the CPU 10 determines whether or not the GPS module 20 can receive GPS radio waves (step S108). When the vehicle can receive GPS radio waves (Yes in step S108), the CPU 10 receives the position information via the GPS module 20, and uses the current time data (Rt) included therein as the current time ( T) (step S109).

  On the other hand, if it is determined in step S108 that GPS radio waves cannot be received, the CPU 10 next determines the current time (T) indicated by the in-vehicle clock 50 and the internal reference time (Gt) recorded in the time data recording unit 32. It is determined whether or not the difference from () exceeds a predetermined threshold (for example, 1 second) (step S110). When the difference between T and Gt exceeds the threshold value, it is determined that there is an error in the in-vehicle clock 50, so it is necessary to correct the time, but if it is within the predetermined threshold value, no correction is required. .

  When the difference between T and Gt exceeds the threshold value, the CPU 10 next determines whether the count number n does not exceed the predetermined threshold value Ns (step S111). The current time (T) indicated by the clock 50 is approximately corrected with the internal reference time (Gt) (step S112).

  Among the above procedures, the procedure that flows from step S108 to step S109 corresponds to, for example, the operation of the in-vehicle recording apparatus when the vehicle after the operation work is stored in a place where GPS radio waves can be received. Since GPS radio waves can be received in a time zone in which the time of the in-vehicle clock can be corrected (when no operation history is recorded), the time of the in-vehicle clock 50 may be corrected with the latest standard time information received. The procedure of step S109 is the same as the time correction operation in the conventional in-vehicle recording device.

  On the other hand, among the above procedures, the procedure that flows from step S108 to step S110, step S111, and step S112 is, for example, on-vehicle recording when the vehicle after the operation work is stored in a place where GPS radio waves cannot be received. This corresponds to the operation of the device. The internal reference time that is updated by adding the timer count value to the latest standard time even if GPS radio waves cannot be received in the time zone in which the time of the in-vehicle clock can be corrected (when the operation history is not recorded) Since it can be regarded as an approximate “standard time”, the time of the in-vehicle clock can be approximately corrected with the internal reference time.

  Thus, conventionally, for example, in a vehicle that is stored in a place where GPS radio waves cannot be received after the end of work, there is a situation in which the time of the in-vehicle clock is not corrected over a long period of time and the error accumulates and a large deviation occurs However, according to the time correction method of the in-vehicle recording device in the embodiment of the present invention, for example, in the case of a vehicle that operates every day, the location of the vehicle in the time zone in which the time of the in-vehicle clock can be corrected Regardless, the time of the in-vehicle clock can be corrected at least once a day. Although it is not strictly an accurate time correction, it effectively eliminates the conventional problem that the time correction of the in-vehicle clock is postponed due to the inability to receive GPS radio waves and the clock error accumulates and the deviation becomes large. Can do.

  After the time correction of the in-vehicle clock 50 is completed in step S109 and step S112, or when the difference between T and Gt does not exceed the threshold value in step S110, the process returns to step S101 and the above procedure is repeated. On the other hand, if the count number n exceeds the predetermined threshold value Ns in step S111, the series of time correction operations is terminated. The reason for ending the series of time adjustment operations in this way is that there is a possibility that the internal reference time has shifted because a long time has passed since the most recent standard time information acquisition, and time correction with appropriate accuracy is required. This is because there is a possibility that it cannot be performed.

  In the above embodiment, it is not necessary that the accuracy of the internal clock of the CPU 10 that is the time measuring means is higher than the accuracy of the timepiece of the in-vehicle timepiece 50. Therefore, the in-vehicle clock 50 and the timer count for calculating the internal reference time can share the internal clock of the CPU 10.

  In the above embodiment, the example using the GPS module 20 as the standard time information acquisition unit has been described. However, the present invention is not limited to this, and the standard time information serving as a reference for the in-vehicle clock 50 can be acquired. Any means can be used.

  As described above, the time correction method of the in-vehicle recording device in the embodiment of the present invention approximates the time of the in-vehicle clock even when the standard time information cannot be acquired in the time zone in which the time of the in-vehicle clock can be corrected. Therefore, it is possible to prevent an increase in clock deviation due to accumulated errors.

  The time correction method of the in-vehicle recording apparatus according to the present invention has an effect of preventing the time deviation of the clock from being enlarged due to the accumulation of errors, and is useful in maintaining the accuracy of the time of the in-vehicle recording apparatus.

10 CPU
20 GPS module 31 Received GPS time data recording unit 32 Timekeeping data recording unit 40 Data processing unit 41 Card interface 50 In-vehicle clock 100 In-vehicle recording device 200 Memory card

Claims (1)

An in-vehicle clock,
Standard time information acquisition means that enables acquisition of information related to the standard time in a predetermined time zone ,
Time correction means for correcting the time of the in-vehicle clock based on the information related to the standard time acquired by the standard time information acquisition means;
A time counting means for performing timer counting;
An in-vehicle recording apparatus comprising:
The time measuring means starts a timer count starting from the standard time acquired most recently,
When the standard time information acquisition unit cannot acquire information related to the standard time in a time zone in which the time of the in-vehicle clock can be corrected, the time correction unit includes the timer count value counted by the timer by the timer unit. Correct the time of the in-vehicle clock with the internal reference time added to the standard time,
An in-vehicle recording apparatus characterized by that.

Images