Timepiece and digital tachograph comprising the timepiece and method of operating a timepiece

Abstract

The invention relates to a time measuring device (3) comprising a quartz oscillator device (4) configured to determine an internal time (TI) of the time measuring device (3), and a receiving device (5) configured to receive an external time (TE) from an external time source (7).The invention comprises the timing device (3) being configured to record a respective time value (ti) of the internal time (TI) and a respective time value (te) of the external time (TE) at a respective time point (τ); to determine a respective time deviation value (Δt) of a time deviation between the time value (ti) of the internal time (TI) and the time value (te) of the external time (TE); to determine an average value (ΔtN) from the respective time deviation values ​​(Δt) of a parameterizable number (N) of the time points (τ) and to check the average value (ΔtN) for fulfillment of a deviation criterion (Δtc) and, if the deviation criterion (Δtc) is fulfilled, to adjust the internal time (TI) in a predetermined compensation interval (Tc) by a compensation value (tc) to reduce the time deviation value (Δt) of the time deviation.

Description

[0001] The invention relates to a time measuring device, a digital tachograph device comprising a time measuring device, and a method for operating a time measuring device.

[0002] Thematically, the invention relates to Commission Implementing Regulation (EU) 2023 / 980 of 16 May 2023 amending Implementing Regulation EU 2016 / 799 as regards transitional measures for the functioning of smart tachographs and their use of Galileo Open Service Navigation Message Authentication, authentication of navigation messages in the Galileo Open Service, and amending Implementing Regulation EU 2021 / 1228.

[0003] Until now, a crystal oscillator device, also known as a real-time clock (RTC), has temperature compensation mechanisms that prevent temperature-dependent time deviations. Furthermore, a crystal oscillator device ages, which also leads to time deviations. It is possible to adjust the time of the crystal oscillator device if a time deviation from an external, reliable time source, such as a global navigation satellite system (GNSS), is detected. A time adjustment of the crystal oscillator device due to the time deviation occurs abruptly, which is why the crystal oscillator device can no longer be trusted as a system's internal time source between time adjustments if the time deviation is too large.

[0004] For example, there is a risk that the time deviation caused by aging of the crystal oscillator device will prevent an authenticated GNSS signal from being used to adjust the RTC's time if the GNSS time, which serves as an external reliable time source, deviates by more than one second per day from the internal time of the crystal oscillator device. If the cumulative time deviation exceeds a threshold of 300 seconds, a vehicle equipped with the tachograph device in question must be taken to an authorized workshop for a time adjustment of the crystal oscillator device.

[0005] EP 3 611 577 A1 discloses a method for regulating the internal time of a tachograph. For this purpose, signals from a satellite navigation system are received. By evaluating the signals, a time specified by the satellite navigation system is determined. A time deviation between the internal time of the tachograph and the time specified by the satellite navigation system is determined. To adjust the internal time of the tachograph to the time specified by the satellite navigation system, a component of a compensation parameter is determined depending on the determined time deviation. Depending on the component of the compensation parameter, the internal time of the tachograph is adjusted to the time specified by the satellite navigation system.

[0006] The approach in the above method is based on changing a divider factor of a real-time clock counter in the tachograph.

[0007] DE 199 31 685 A1 discloses a method for generating a time signal. In the method, an incoming reference signal is compared with a signal from a real-time clock. The comparator's output signal is ANDed with the reference signal to a binary counter, where it is incremented or decremented depending on the result of the comparison. The output of the binary counter is fed to one input of a cyclic adder, whose carry is used to enable the clock of the real-time clock counter. The other input receives the signal previously generated by the cyclic adder from a register.

[0008] US 2010 0045523 A1 describes a method for compensating clock skew in a GNSS receiver. The method comprises deriving at least one clock skew value, which includes a first clock skew value corresponding to a first time point, and calculating the clock skew according to the at least one clock skew value and at least one interval within the period between the first time point and a specific time point after the first time point. An apparatus for compensating clock skew in a GNSS receiver is also provided.

[0009] It is an object of the invention to avoid time conflicts between a quartz oscillator device and an external, reliable time source. In particular, it is an object of the invention to enable the use of an authenticated GNSS signal by comparing an internal time of the quartz oscillator device with an external time. Furthermore, it is an object of the invention to enable the use of less accurate, yet more cost-effective quartz oscillator devices by compensating for a time discrepancy between the internal time and the external time.

[0010] The problem is solved by the subject matter of the independent patent claims. Advantageous further developments of the invention are described by the dependent patent claims, the following description, and the figures.

[0011] A first aspect of the invention relates to a time-measuring device. The time-measuring device comprises a quartz oscillator device configured to determine an internal time of the time-measuring device. The time-measuring device further comprises a receiving device configured to determine an external time from an external time source. The receiving device can be configured to receive one or more time signals from the external time source and to determine the external time based on the time signals. In other words, the internal time of the time-measuring device is determined by the quartz oscillator device of the time-measuring device. The external time is provided to the time-measuring device via the receiving device from the external time source. The external time can be provided, for example, by a radio clock or a satellite-based navigation system.

[0012] A discrepancy may occur between the internal and external time. This may be due to fluctuations in the resonant frequency of the quartz oscillator device. It can be assumed that the external time is more accurate than the internal time. The external time can be considered the reference time. In other words, a discrepancy between the internal and external time is assumed to be due to an inaccuracy in the timing device.

[0013] It is provided that the time measuring device is configured to record a respective time value of the internal time and a respective time value of the external time at a respective point in time and to determine a respective time deviation value of a time deviation between the time value of the internal time and the time value of the external time. In other words, the internal time is compared with the external time by the time measuring device. In the comparison, the respective time value of the internal time is compared with the respective time value of the external time at the respective point in time. For the point in time, a respective time deviation value of a time deviation between the time value of the internal time and the time value of the external time is determined. The time deviation value can be a difference between the time value of the internal time and the time value of the external time.

[0014] The time measuring device is configured to determine an average value of the time deviation of the time window from the respective time deviation values ​​of a configurable number of times of a continuous time window. In other words, respective time deviation values ​​of the time deviation are determined at the respective times. The time deviation values ​​can be determined continuously. The respective times can be separated from one another by regularly specified time intervals. The time value of the internal time can deviate in one direction due to a systematic error. The respective time value can also deviate in both directions due to noise. In order to be able to compensate for the noise, it is provided to determine the average value of the time deviation of the time window.

[0015] Because the times are continuously measured, a combination of the times of the time window changes continuously and thus the average value of the time deviation of the time window. The time measuring device is configured to check the average value of the time deviation of the time window for fulfillment of a deviation criterion. The deviation criterion can, for example, relate to the average value of the time deviation of the time window exceeding and / or falling below a predetermined threshold value. The time measuring device is configured to adjust the internal time in a compensation interval by a compensation value to reduce the time deviation value if the deviation criterion is met. In other words, the time measuring device is configured to adjust the internal time when the deviation criterion is met.The internal time is adjusted by a compensation value which is added to or subtracted from the internal time.

[0016] In other words, the reduction of the time deviation is achieved by changing the internal time by a compensation value within the compensation interval. For example, the compensation interval can be predefined in the time-measuring device. The compensation interval can specify compensation times intended for adjusting the internal time by the compensation value. Whether the internal time is adjusted by the compensation value at the respective compensation time depends on the deviation criterion being met. For example, the compensation value can be added to the internal time at the respective compensation time if the average value of the time deviation of the time window at the respective compensation time meets the deviation criterion.

[0017] The invention also includes further developments which result in additional advantages.

[0018] A further development of the invention provides that the compensation interval of the time measuring device is predetermined, and the time measuring device is configured to determine the compensation value as a function of the average value of the time deviation. In other words, the compensation interval is predetermined and not selected as a function of the average value of the time deviation. The compensation value is selected by the time measuring device as a function of the average value of the time deviation. For example, it can be provided that the compensation value is selected proportional to the average value of the time deviation. This further development provides the advantage that the extent of the average value of the time deviation can be compensated by selecting the compensation value.

[0019] A further development of the invention provides that a lower limit and / or an upper limit is specified for the time measuring device for determining the compensation value. In other words, conditions with regard to the compensation value are specified for the time measuring device, which include that the compensation value does not fall below a lower limit and / or that the compensation value does not exceed an upper limit. It can thus be provided that the time measuring device is restricted in its determination of the compensation value by the limit values. This can be provided, for example, in order to avoid errors that can occur due to an excessive change in the internal time. It can, for example, be the case that an actual compensation value is determined by the time measuring device for the average value of the time deviation, which would exceed the upper limit.In this case, the timing device could set the compensation value of a specific compensation time to the upper limit. The timing device could determine a difference between the actual compensation value and the upper limit as the compensation value of a compensation time following the specific compensation time.

[0020] A further development of the invention provides that the compensation value is predetermined for the time measuring device, and the time measuring device is configured to determine the compensation interval as a function of the average value of the time deviation. In other words, the compensation value is predetermined. The compensation value can be, for example, 1 second. The time measuring device is configured to select the compensation interval as a function of the average value of the time deviation. For example, the compensation value can be 1 second, and the compensation interval for adding or subtracting the second is selected as a function of the average value of the time deviation. For example, the compensation interval can be selected to be inversely proportional to the average value of the time deviation.

[0021] A further development of the invention provides that a lower limit and / or an upper limit is specified for the timing device for determining the compensation interval. In other words, conditions for selecting the compensation interval are specified in the timing device. For example, it can be provided that the compensation interval may not be shorter than the lower limit and not longer than the upper limit.

[0022] A further development of the invention provides that the receiving device is configured to receive satellite-based navigation signals. In other words, the receiving device comprises a receiver for satellite-based navigation signals. In other words, the time-measuring device has the receiving device, which is configured to receive the signals of a satellite-based navigation system. For example, it can be provided that the receiving device is configured to receive signals from the GPS, Glonass, and / or Galileo system and to determine the external time based on the received signals. This results in the advantage that the receiving device is configured to use a globally available system for determining the external time.

[0023] A further development of the invention provides that the receiving device is configured to receive mobile radio signals. In other words, the receiving device comprises a receiver for mobile radio signals. In other words, the receiving device is configured to receive mobile radio signals and determine the external time based on the received mobile radio signals. This further development offers the advantage that the external time can also be determined in locations where no satellite signals can be received. This can be the case, for example, near densely built-up areas or tunnels.

[0024] A further development of the invention provides that the receiving device is configured to receive radio clock signals. In other words, the receiving device comprises a receiver of radio clock signals. In other words, the receiving device is configured to receive time signal signals from a time signal transmitter and to determine the external time based on the received time signal signals. These can be time signal signals from the DCF77 time signal transmitter, for example.

[0025] A further development of the invention provides that the receiving device is configured to receive Network Time Protocol signals. In other words, the receiving device comprises a receiver of Network Time Protocol signals. In other words, the receiving device is configured to determine the external time based on Network Time Protocol signals.

[0026] A second aspect of the invention relates to a digital tachograph device having a time-measuring device. In other words, the second aspect relates to the digital tachograph device comprising the time-measuring device. The time-measuring device is configured to provide the tachograph device with an internal time. The tachograph device has the advantage that it is provided with an internal time that is checked against an external time.

[0027] A third aspect of the invention relates to a method for operating a time-measuring device. The time-measuring device comprises a quartz oscillator device configured to determine an internal time of the time-measuring device. The time-measuring device has a receiving device configured to receive an external time from an external time source. The method provides that the time-measuring device detects a respective time value of the internal time and a respective time value of the external time at a respective point in time, and determines a respective time deviation value of a time deviation between the time value of the internal time and the time value of the external time.

[0028] The time measuring device determines an average value of the time deviation of the time window from the respective time deviation values ​​of a parameterizable number of times of a continuous time window.

[0029] The timing device checks the average value of the time deviation values ​​of the time window for compliance with a deviation criterion. If the deviation criterion is met, the timing device adjusts the internal time in a compensation interval by a compensation value to reduce the time deviation.

[0030] To carry out the described steps, a processor circuit may be provided that has programming or software comprising program instructions that, when executed, cause the processor circuit to perform an embodiment of the method. For this purpose, the processor circuit may comprise at least one microprocessor and / or microcontroller. The program instructions may be stored in a data memory of the processor circuit.

[0031] The invention also includes further developments of the method according to the invention that have features already described in connection with the further developments of the time-measuring device according to the invention. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0032] For use cases or application situations that may arise during the method and which are not explicitly described here, it may be provided that, in accordance with the method, an error message and / or a request to enter user feedback is issued and / or a default setting and / or a predetermined initial state is set.

[0033] The invention also includes combinations of the features of the described embodiments.

[0034] An exemplary embodiment of the invention is described below. It shows: Fig. 1 shows a schematic representation of a motor vehicle; Fig. 2 shows a schematic representation of a method for operating a time-measuring device; Fig. 3 shows a schematic representation of a sequence of a method for operating a time-measuring device; Fig. 4 shows a schematic representation of a sequence of determining a time deviation between a respective time value of the internal time and a respective time value of the external time at respective points in time; Fig. 5 shows a schematic representation of a profile of a time deviation between the internal time and the external time; Fig. 6 shows a further schematic representation of a profile of a time deviation between the internal time and the external time; Fig. 7 shows a further schematic representation of a profile of a time deviation between the internal time and the external time; Fig. 8 shows a further schematic representation of a profile of a time deviation between the internal time and the external time; and Fig.9A further schematic representation of a time deviation curve between the internal time and the external time.

[0035] The exemplary embodiment explained below is a preferred embodiment of the invention. In the exemplary embodiment, the described components of the embodiment each represent individual, independently considered features of the invention, which also further develop the invention independently of one another and are thus also to be considered as components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

[0036] In the figures, functionally identical elements are provided with the same reference numerals.

[0037] Fig. 1 shows a schematic representation of a motor vehicle having a tachograph device comprising a time measuring device.

[0038] Shown is a schematic representation of a motor vehicle 1, for example a truck, which may have a digital tachograph device 2. The digital tachograph device 2 may have a time measuring device 3. The time measuring device 3 may have a quartz oscillator device 4, which may be configured to determine an internal time TI. The time measuring device 3 may have a receiving device 5, which may be configured to receive signals 6 from an external time source 7 and to determine an external time TE based on the received signals 6. The time measuring device 3 may be configured to determine a respective time value te of the external time TE and a respective time value ti of the internal time TI at respective times τ.The time measuring device 3 is configured to determine, for the respective time τ, a respective time deviation value Δt between the time value te of the external time TE and the time value ti of the internal time TI. The times τ can have a specific interval. For a parameterizable number N of times τ, an average value ΔtN of the time deviation can be determined. Since the average value ΔtN is determined from the last N time deviation values ​​Δt, the average value ΔtN represents the average of the time deviation values ​​Δt of a moving window.

[0039] The time measuring device 3 can be configured to check the average value ΔtN for fulfillment of a deviation criterion. For this purpose, the time measuring device 3 can, for example, be configured to compare the average value ΔtN with a threshold value tk. Exceeding the threshold value tk can represent fulfillment of the deviation criterion. If the deviation criterion is met, the time measuring device 3 can be configured to adjust the internal time TI in a compensation interval Tc by a compensation value tc to reduce the time deviation value Δt. The compensation interval Tc can be determined by the time measuring device 3 as a function of the time deviation value Δt. The selection of the compensation interval Tc can be limited by an upper and / or a lower limit.It can also be provided that the compensation value tc is selected depending on the time deviation value Δt, and its selection is also limited by an upper and lower limit. It can be provided that both the compensation interval Tc and the compensation value tc are predetermined, and the change in the internal time TI by the compensation value tc in the compensation interval Tc depends on the fulfillment of the deviation criterion.

[0040] Fig. 2 shows a schematic representation of a method for operating a time measuring device.

[0041] The external time source 7 can provide signals 6, which can be received by the receiving device 5. The time measuring device 3 can determine the external time TE from the signals 6. The time measuring device 3 can be specified with the parameterizable number N of times τ of a continuous time window. The number N refers to the times τ from whose time deviation values ​​Δt the average value ΔtN of the time deviation of the time window can be determined. It can be provided that the internal time TI is adjusted by the time measuring device 3 if the deviation criterion is met by the average value ΔtN of the time deviation.

[0042] Fig. 3 shows a schematic representation of a sequence of a method for operating a time measuring device;

[0043] In a step S1, at least one signal 6 from an external time source 7 can be received by a receiving device 5 of the time measuring device 3. Based on the received signal 6, an external time TE can be determined by the time measuring device 3.

[0044] In a step S2, the time-measuring device 3 can compare an internal time TI, which can be provided by a quartz oscillator device 4, with the determined external time TE. The comparison can, for example, provide that, for a time τ, a respective time value te of the external time TE is compared with a time value ti of the internal time TI, and a time deviation value Δt of the time deviation between the time value ti of the internal time TI and the time value te of the external time TE is determined.

[0045] In a step S3, an average value ΔtN of the time deviation can be determined from the time deviation values ​​Δt of a parameterizable number N of times τ.

[0046] In a step S4, the time measuring device 3 can adjust the internal time TI in a compensation interval Tc by a compensation value tc if, for example, the average value ΔtN of the time deviation exceeds a predetermined threshold value tk.

[0047] Fig. 4 shows a schematic representation of a process for determining a time deviation between a respective time value of the internal time and a respective time value of the external time at respective points in time.

[0048] A course of the internal time TI can deviate from a course of the external time TE. This can be attributed, for example, to one of the quartz oscillator devices 4. In addition to a continuous increase in the deviation, fluctuations can occur which can be attributed to noise or short-term fluctuations. In order to compensate for these fluctuations, the average value ΔtN of the time deviation is calculated over the time window which comprises the last N points in time τ. The determined average value ΔtN can be compared with a predetermined threshold value tk. If the threshold value tk is exceeded, a deviation criterion can be met and compensation of the internal time TI can be carried out. For example, it can be provided that a compensation interval Tc is predetermined, which can specify compensation times at which compensation of the internal time TI can take place.It can be provided that if the threshold value tk is exceeded, the compensation value tc of the internal time TI is added to the internal time TI at a next compensation time point.

[0049] Fig. 5 shows a schematic representation of a time deviation between the internal time and the external time over time T.

[0050] It can be provided that a permissible maximum value Δtmax of the time deviation Δt is specified for the time measuring device 3. If the time deviation value Δt is greater than the maximum value Δtmax of the time deviation Δt, this can be detected as a time conflict and stored in the time measuring device 3. In the illustrated Fig. 5 no compensation of a deviation takes place and at a time T1 the maximum value Δtmax of the time deviation Δt is exceeded by the time deviation value Δt.

[0051] The following figures describe ways to avoid exceeding the maximum value Δtmax of the time deviation Δt by the time deviation value Δt.

[0052] Fig. 6 shows a schematic representation of a course of the time deviation over time T during compensation.

[0053] Starting from a time T1, the internal time TI can be adjusted by 1 second every other day.

[0054] Starting at a time T2, the internal time TI can be adjusted by 1 second on each day.

[0055] The internal time TI can be compensated in a specified time interval.

[0056] Fig. 7 shows a further schematic representation of a course of the time deviation over time T.

[0057] Shown is the curve over a time T when the internal time TI is compensated within a specified compensation interval Tc. Additionally, the time deviation is reset to 0 seconds during the time adjustment.

[0058] Fig. 8 shows a further schematic representation of a course of the time deviation over time T.

[0059] The curve is shown when the internal time is compensated in variable drift-dependent compensation intervals.

[0060] Fig. 9 shows a further schematic representation of a course of the time deviation over time T.

[0061] Shown is the time T curve when the internal time is compensated in variable drift-dependent compensation intervals. Additionally, a time adjustment is shown that resets the deviation to 0 seconds.

[0062] Time values ​​of an external time from a precise external reference time source, such as GNSS, are determined at different points in time and compared with the internal time values ​​of the quartz oscillator device. For a configurable number of time deviation values ​​at each point in time, a smoothed average time deviation, an average of the time deviation values, is calculated. From the calculated average time deviation, a compensation interval can be calculated, within which a temporal compensation of the internal time can be made by a compensation value. The compensation value and the compensation interval can be configured such that the extent of the compensation of the internal time is below a legally considered time adjustment.In order to be able to react to a temporal change in the time deviation of the internal time determined by the quartz oscillator device compared to the external time, the time values ​​of the external time, which can be provided, for example, by respective GNSS samples, can be used in a digital tachograph application according to a first-in, first-out principle to calculate the average value of the time deviation. If the required number is exceeded, the oldest time value is no longer considered for the average value.

[0063] In the event that the receiver device, which in this example comprises a GNSS receiver, is not supplied with power and therefore does not provide current external time values, time compensation can be performed using the most recently determined compensation value per compensation interval. In this case, for example, the compensation value of the day on which the receiver device was active and provided external time values ​​can be used.

[0064] Overall, the example shows how a solution can be provided to compensate for a time deviation of the internal time from the external time. List of reference symbols

[0065] 1 Motor vehicle 2 Tachograph device 3 Time measuring device 4 Quartz oscillator device 5 Receiving device 6 Signal 7 External time source TI Internal time TE External time T Time τ Time point T1 First time T2 Second time te Time value of the external time ti Time value of the internal time Tc Compensation interval Δt Time deviation value tc Compensation value N Number of times Δt N Average value of the time deviation Δtc Deviation criterion tk Threshold value Δtmax Maximum value of the time deviation value

Claims

1. Time measuring device (3), comprising a quartz oscillator device (4) configured to determine an internal time (TI) of the time measuring device (3) and a receiving device (5) configured to receive an external time (TE) of an external time source (7), d characterized bythat the time measuring device (3) is set up to - record a respective time value (ti) of the internal time (TI) and a respective time value (te) of the external time (TE) at a respective point in time (τ) and to determine a respective time deviation value (Δt) of a time deviation between the time value (ti) of the internal time (TI) and the time value (te) of the external time (TE); - determine an average value (ΔtN) of the time deviation of the time window from the respective time deviation values ​​(Δt) of the time deviations of a parameterizable number (N) of the points in time (τ) in a continuous time window; - check the average value (ΔtN) of the time deviation of the time window for compliance with a deviation criterion (Δtc);and - if the deviation criterion (Δtc) is met, the internal time (TI) is adjusted in a predetermined compensation interval (Tc) by a compensation value (tc) to reduce the time deviation value (Δt) of the time deviation.

2. Time measuring device (3) according to claim 1, characterized in that the compensation interval (Tc) of the time measuring device (3) is predetermined and the time measuring device (3) is designed to determine the compensation value (tc) as a function of the average value (ΔtN) of the time deviation.

3. Time measuring device (3) according to claim 2, characterized in that the time measuring device (3) is preset with a lower limit value and / or an upper limit value for determining the compensation value (tc).

4. Time measuring device (3) according to claim 1, characterized in thatthe compensation value (tc) is predetermined for the time measuring device (3) and the time measuring device (3) is designed to determine the compensation interval (Tc) as a function of the average value (ΔtN) of the time deviation.

5. Time measuring device (3) according to claim 4, characterized in that the time measuring device (3) is preset with a lower limit value and / or an upper limit value for determining the compensation interval (Tc).

6. Time measuring device (3) according to one of the preceding claims, characterized in that the receiving device (5) is designed to receive satellite-based navigation signals (6).

7. Time measuring device (3) according to one of the preceding claims, characterized in that the receiving device (5) is configured to receive mobile radio signals (6).

8. Time measuring device (3) according to one of the preceding claims, characterized in thatthe receiving device (5) is designed to receive radio clock signals (6).

9. Time measuring device (3) according to one of the preceding claims, characterized in that the receiving device (5) is configured to receive Network Time Protocol signals (6).

10. Digital tachograph device (2) comprising a time measuring device (3) according to one of the preceding claims.

11. Method for operating a time measuring device (3), comprising a quartz oscillator device (4) configured to determine an internal time (TI) of the time measuring device (3) and a receiving device (5) configured to receive an external time (TE) of an external time source (7), d characterized bythat by means of the time measuring device (3), - a respective time value (ti) of the internal time (TI) and a respective time value (te) of the external time (TE) are recorded at a respective point in time (τ) and a respective time deviation value (Δt) of a time deviation between the time value (ti) of the internal time (TI) and the time value (te) of the external time (TE) is determined; - an average value (ΔtN) of the time deviation values ​​(Δt) of the time deviation of the time window is determined from the respective time deviation values ​​(Δt) of the time deviation of a parameterizable number (N) of the points in time (τ) of a continuous time window; - the average value (ΔtN) of the time deviation of the time window is checked for compliance with a deviation criterion (Δtc); and - when the deviation criterion (Δtc) is met, the internal time (TI) is adjusted in a compensation interval (Tc) by a compensation value (tc) to reduce the time deviation value (Δt) of the time deviation.

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