Method for correcting measurement data tuples of a mobile unit on the basis of a reference time, and measuring device

Abstract

The invention relates to a method for correcting measurement data tuples (MT) captured in a mobile unit which has an intrinsic time (EZ) defined by a clock (U), said measurement data tuples comprising time stamps (t1, t2), which are defined by means of the intrinsic time (EZ), and measurement values (MW), wherein error events change the intrinsic time (EZ), the method comprising: establishing a connection (V) between the mobile unit (ME) and a superordinate unit (ÜE) having a reference time (RZ); forming a first time difference (DZ1) between a connection time (tV) defined by the intrinsic time (EZ) and a connection time (TV) defined by the reference time (RZ); performing a correction process if the first time difference (DZ1) is greater than a threshold value, comprising: reading a time stamp (t1, t2), determining a second time difference (DZ2) between the time stamp (t1, t2) and the connection time (TV) defined by the reference time (RZ), classifying the time stamp (t1, t2) as erroneous if the second time difference (DZ2) is greater than the threshold value, replacing erroneous time stamps (t1, t2) with corrected time stamps (t1, t2), the corrected time stamps (t1, t2) being a function of the erroneous time stamps (t1, t2) and the first time difference (DZ1).

Description

[0001] Method for correcting measurement data tuples of a mobile unit using a reference time and measuring device

[0002] The invention relates to a method for correcting tuples of measurement data from a mobile unit with a local time or proper time, using a reference time provided by a higher-level unit. The invention further relates to a measuring device configured to perform the method according to the invention.

[0003] Document DE102017108571A1 describes a method for transmitting time-synchronized data from a local controller of an automation system to another participant in the automation system, whereby the local time of the controller is repeatedly synchronized with the reference time of a server. This described method allows data originating from the local controller to be continuously timestamped with each connection and compared with data from other controllers. The method enables the comparison and processing of data from different controllers at the same time.

[0004] Patent DE102017212353A1 discloses a method that synchronizes sensor data from a sensor system with the host time base of a host system by determining the clock ratio between the two time bases. Timestamps of communication processes are recorded to determine the clock ratio and detect irregularities. If necessary, the host timestamp of transmitted sensor data is corrected or replaced. The patent further discloses a device for carrying out the method.

[0005] Synchronizing systems, for example between local units and higher-level units, where each system has its own clock, can be complicated by error events, especially if the systems are out of contact for an extended period. Error events are events that affect the clocks of systems with data to be synchronized (hereinafter referred to as mobile units) in such a way that the time defined by these clocks (hereinafter referred to as proper time) is changed, for example, by being reset to a starting value in the past.

[0006] According to the state of the art, mobile units are regularly in contact with a higher-level unit, for example, a host system. This allows for synchronization of the mobile system's own time with the reference time of the higher-level unit, thus ensuring the continuous temporal sequence of data acquired and / or transmitted by the mobile unit. However, the state of the art presents a problem: if error events occur during a prolonged separation between the mobile unit and the higher-level unit, the temporal continuity of the data acquired and stored in the mobile unit—for example, measurement data with timestamps from a ship prepared for refueling—cannot be guaranteed.

[0007] The invention therefore aims to ensure the temporal continuity of measurement data stored in a mobile unit, wherein the mobile unit is separated from a higher-level unit for an extended period of time.

[0008] The invention solves the problem by means of a method according to independent claim 1 and by means of a measuring device according to dependent claim 14.

[0009] The inventive method for correcting measurement data tuples, wherein the measurement data tuples each comprise a timestamp and at least one measured value, wherein the measurement data tuples are acquired and stored in a mobile unit, wherein the mobile unit has a proper time, wherein the proper time is defined by a clock, wherein in the event of an error event the proper time is changed by the error event, wherein the timestamps are defined by means of the proper time, comprises at least the following steps: establishing a connection between the mobile unit and a higher-level unit, wherein the higher-level unit has a reference time; forming a first time difference between a connection time defined by the proper time and a connection time defined by the reference time;Starting a correction process if the first time difference is greater than a threshold, wherein the correction process comprises a procedure that is performed for each measurement data tuple, the procedure comprising: reading at least one timestamp of a measurement data tuple, determining a second time difference between the timestamp and the connection time defined by the reference time, classifying the timestamp as erroneous if the second time difference is greater than the threshold, replacing timestamps classified as erroneous with a corrected timestamp, wherein a corrected timestamp is a function of the erroneous timestamp and the first time difference.

[0010] In a further development of the method according to the invention, the fault event comprises a temporary interruption of the power supply to the clock.

[0011] In a further development of the method according to the invention, the proper time is set to a starting value when the fault event occurs. In a further development of the method according to the invention, the threshold value is at least one year, in particular at least ten years, preferably at least 40 years.

[0012] In a further development of the method according to the invention, a corrected timestamp comprises a sum of the first time difference and an erroneous timestamp.

[0013] In a further development of the inventive method, the correction of the timestamps is carried out by the mobile unit.

[0014] In a further development of the method according to the invention, the correction of the timestamps is carried out by the higher-level unit.

[0015] In a further development of the method according to the invention, the network is wireless.

[0016] In a further development of the method according to the invention, the measurement data tuples are acquired by a measuring device; wherein the measuring device is arranged on the mobile unit.

[0017] In a further development of the method according to the invention, the measuring device is a flow meter or a level meter.

[0018] In a further development of the inventive method, the mobile unit is a ship.

[0019] In a further development of the method according to the invention, the mobile unit is disconnected from the network during a first period of time; wherein the mobile unit is connected to the network during a second period of time.

[0020] In a further development of the method according to the invention, the error event occurs during the first time period.

[0021] In a further development of the method according to the invention, the timestamps classified as faulty are stored in a separate storage unit; wherein the faulty timestamps are corrected on the basis of information stored in the storage unit, in particular collected.

[0022] The measuring device according to the invention, configured for acquiring measurement data, comprises: a sensor, wherein the sensor is arranged on a container, the container comprising a medium; a storage unit, configured to store tuples of measurement data, wherein a tuple of measurement data comprises acquired measured values ​​and timestamps defined by the proper time; a communication unit, configured to be connected to a higher-level unit with a reference time; a computer unit with a clock with a proper time, configured, in the event of a connection to the higher-level unit, to correct the timestamps of the stored measurement data tuples by means of one of the embodiments of the method according to the invention and to transmit the optionally corrected measurement data tuples to the higher-level unit.

[0023] The invention has the advantage that timestamps of measurement data from a mobile unit, which exhibit a temporal discontinuity due to a change in the mobile unit's proper time caused by an error event, can be converted into a temporally continuous sequence. The method according to the invention has the advantage that it can be used for the operation of bunkering vessels, so that the data tuples transmitted to the higher-level unit (for example, a cloud-based service provider) contain timestamps that allow the measured values, for example, from a medium transmitted to a customer, to be assigned to a refueling period and thus to a customer. The invention further has the advantage that the method can be applied both in the mobile unit and in the higher-level unit.Furthermore, the method according to the invention can be implemented in a measuring device according to the invention, so that measured values ​​are automatically provided with correct timestamps upon transmission. A further advantage is that the method according to the invention can operate in the cloud, so that the measurement data can be corrected whenever a mobile unit connects to the internet. Finally, it is advantageous that erroneous data is not lost and can be corrected automatically.

[0024] The invention is explained in more detail with reference to the exemplary embodiments shown in the following figures. These show:

[0025] Fig. 1 shows an embodiment of the process steps according to the invention.

[0026] Fig. 2 shows an illustration of the connection between the mobile and the higher-level unit. Fig. 3 shows an example of the relationship between proper time and reference time.

[0027] Fig. 4 shows an embodiment of the measuring device according to the invention.

[0028] The embodiment of the method according to the invention shown in Fig. 1 begins with the process step "acquiring and storing measurement data tuples MT in the mobile unit ME," which process step comprises the measured values ​​MW and timestamps t1, t2 defined by the proper time EZ. Establishing a connection V with a higher-level unit ÜE enables the comparison of the proper time EZ and the reference time RZ, from which a first time difference ZD1 is initially determined. If the first time difference ZD1 is greater than a threshold value, which in this example is at least one year, in particular at least ten years, and preferably at least 40 years, a correction process for the measurement data tuples MT is initiated.In this correction process, each measurement data tuple MT, comprising a timestamp t1, t2, is read in individually. A second time difference ZD2 is determined, which in this example is formed by the difference between the timestamps t1, t2 and the reference time. If this second time difference ZD2 is greater than a threshold, which in this embodiment is at least one year, in particular at least ten years, and preferably at least 40 years, the measurement data tuple MT is classified as erroneous. In a further process step, erroneous measurement data tuples MT are corrected by replacing the timestamps t1, t2 of the erroneous measurement data tuples MT with corrected timestamps t2', in this example by calculating the sum of the timestamps t1, t2 and the first time difference ZD1.Finally, the corrected measurement data tuples are transmitted from the mobile unit ME to the higher-level unit ÜE, in this specific example via a wireless network.

[0029] The embodiment of the connection V between the mobile unit ME and the higher-level unit ÜE shown in Fig. 2 depicts the mobile unit ME, comprising a clock U with a proper time EZ and a measuring device MG, which includes measured values ​​MW, which are measured values ​​MW from measurement data tuples MT, together with timestamps t1, t2 defined by the proper time EZ. The connection V is provided by a network N, which in this embodiment is a wireless network and connects the mobile unit ME to the higher-level unit ÜE. In this embodiment, the mobile unit ME is a ship, and the higher-level unit can be, for example, another ship, a port, a port facility, or a cloud-based server platform.

[0030] In Fig. 3, the proper time EZ is represented by the vertical axis, and the reference time RZ by the horizontal axis. In this example, the proper time EZ is defined by a clock U located in a mobile unit and refers to time values ​​tS, t1, t2, tE, tV, t2', tV', and the reference time RZ, which applies to a higher-level unit ÜE, refers to time values ​​T1, T2, TE, TV. The mobile unit is separated from the higher-level unit ÜE for a first time interval ZS1, i.e., for times defined by the reference time RZ that lie before TV, and for a second time interval ZS2, i.e., for times defined by the reference time RZ that lie after TV, the mobile unit ME is connected to the higher-level unit ÜE.

[0031] For any given event, the temporal relationship between a time point in proper time (PT) assigned to the event and a time point in reference time (RT) assigned to the event is represented by diagonal black lines. The events of measurements MW1 and MW2 are represented by black dots, which occur at times t1 and t2 in proper time (PT) and at times T1 and T2 in reference time (RT). The error event FE, represented by a black dot, occurs at time tE in proper time (PT) and at time TE in reference time (RT). The error event FE causes the proper time (PT) to be set to a starting value sT, which in this example precedes the measurement MW1 at time t1 in proper time, so that the time t2 of measurement MW2, defined in proper time (PT), precedes the earlier measurement MW1.In this example, the relationship between proper time EZ and reference time RZ is the same before and after the fault event FE, meaning that the clock U is essentially synchronized with a clock measuring the reference time RZ, for example, a clock located in the higher-level unit. At a time tV in the proper time EZ and at a time TV in the reference time, a connection V is established between the mobile unit ME and the higher-level unit ÜE. From this moment onward, a first time difference ZD1 can be determined by calculating the difference between two time points, for example, between TV and tV. This first time difference ZD1 indicates whether a fault event FE has occurred, for example, if the first time difference is greater than a threshold of at least one year, in particular at least ten years, and preferably at least 40 years.In this case, the inventive method can be used to determine that a timestamp t2 is faulty, and a corrected timestamp t2' can be formed by, for example, adding t2 and ZD1.

[0032] The embodiment of the measuring device MG according to the invention, shown in Fig. 4, is arranged on a container B carrying a medium M, which in this specific case can be a measuring tube. The measuring device comprises a sensor MA, which is in direct contact with the container B and generates a measurement signal, which in turn serves to generate a measured value MW. This measured value MW, together with a timestamp t1, t2, is stored by the computer unit CE as a measurement data tuple MT in the storage unit SE. A connection V to a higher-level unit is established by means of the communication unit KE. After the connection V is established, the computer unit CE carries out the method according to the invention to correct any erroneous measurement data tuple MT that may be present. In this embodiment, the communication unit KE transmits the corrected measurement data tuples MT to the higher-level unit ÜE. List of reference numerals

[0033] MT measurement data tuple t1, t2 timestamp

[0034] MW measured value

[0035] EZ Own Time

[0036] U o'clock

[0037] FE error event

[0038] V connection

[0039] ME mobile unit

[0040] ÜE (superordinate unit)

[0041] RZ Reference Time

[0042] DZ1 first time difference tV connection time defined by proper time

[0043] TV connection time defined by the reference time

[0044] DZ2 second time difference tS starting value

[0045] N network

[0046] MG measuring device

[0047] ZS1 first period

[0048] ZS2 second time period

[0049] MA sensor

[0050] B Container

[0051] M Medium

[0052] SE storage unit

[0053] KE Communication Unit

[0054] CE computer unit

Claims

Patent claims 1. A method for correcting measurement data tuples (MT), wherein the measurement data tuples each comprise a timestamp (t1, t2) and at least one measured value (MW), wherein the measurement data tuples (MT) are acquired and stored in a mobile unit, wherein the mobile unit has a proper time (EZ), wherein the proper time (EZ) is defined by a clock (U), wherein in the event of an error event occurring the proper time (EZ) is changed by the error event (FE), wherein the timestamps (t1, t2) are defined by means of the proper time (EZ), wherein the method comprises at least the following steps: • Establishing a connection (V) between the mobile unit (ME) and a higher-level unit (TR), o wherein the higher-level unit (TR) has a reference time (RT); • Forming a first time difference (DZ1) between a connection time (tV) defined by proper time (EZ) and a connection time (TV) defined by reference time (RZ); • Starting a correction process if the first time difference (DZ1) is greater than a threshold, wherein the correction process comprises a procedure that is performed for each measurement data tuple (MT), the procedure comprising: o Reading at least one timestamp (t1, t2) of a measurement data tuple (MT), o Determining a second time difference (DZ2) between the timestamp (t1, t2) and the link time (TV) defined by the reference time (RZ), o Classifying the timestamp (t1, t2) as erroneous if the second time difference (DZ2) is greater than the threshold, o Replacing timestamps (t1, t2) classified as erroneous with a corrected timestamp (t1, t2), o where a corrected timestamp (t1, t2) is a function of the erroneous timestamp (t1, t2) and the first time difference (DZ1).

2. Method according to claim 1 , • where the fault event (FE) includes a temporary interruption of the power supply to the clock (U).

3. Method according to one of claims 1 or 2, • where, upon the occurrence of the fault event (FE), the proper time (EZ) is set to a starting value (tS).

4. Method according to any one of claims 1 to 3, where the threshold is at least 1 year, in particular at least 10 years, preferably at least 40 years.

5. Method according to any one of claims 1 to 4, • where a corrected timestamp (t1, t2) comprises a sum of the first time difference (DZ1) and an erroneous timestamp (t1, t2).

6. Method according to any one of claims 1 to 5, • where the correction of the timestamps (t1 , t2) is performed by the mobile unit (ME).

7. Method according to any one of claims 1 to 6, • where the correction of the timestamps (t1 , t2) is performed by the higher-level unit (TRU).

8. Method according to claim 7, • where the network (N) is wireless.

9. Method according to any one of claims 1 to 8, • where the measurement data tuples (MT) are acquired by a measuring instrument (MG); • wherein the measuring instrument (MG) is arranged on the mobile unit (ME).

10. Method according to any one of claims 1 to 9, • where the measuring instrument (MG) is a flow meter or a level meter.

11. Method according to any one of claims 1 to 10, • where the mobile unit (ME) is a ship.

12. Method according to any one of claims 1 to 11, • wherein the mobile unit (ME) is disconnected from the network for an initial period of time (ZS1); • where the mobile unit (ME) is connected to the network during a second time period (ZS2).

13. Method according to claim 12, • where the fault event (FE) occurs during the first time interval (ZS1).

14. Method according to any one of claims 1 to 13, • where the timestamps classified as faulty (t1, t2) are stored in a separate storage unit; • where the erroneous timestamps (t1 , t2) are corrected using information stored in the storage unit, in particular collected.

15. Measuring device, set up for recording measurement data, comprising: • a sensor (S), o wherein the sensor (S), o is arranged on a container (B), o wherein the container (B) comprises a medium (M); • a storage unit (SE) configured to store measurement data tuples (MT), o wherein a measurement data tuple (MT) comprises recorded measurement values ​​(MW) and timestamps (t1, t2) defined by the proper time (EZ); • a communication unit (CU) set up to be connected to a higher-level unit (TR) with a reference time (RT); • a computer unit (CE) with a clock (U) with a proper time (EZ), configured to correct the timestamps (t1, t2) of the stored measurement data tuples (MT) in the event of a connection (V) with the superior unit (ÜE) by means of a method according to one of claims 1 to 14 and to transmit the possibly corrected measurement data tuples (MT) to the superior unit (ÜE).

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