Verification of time information transmitted by time signals or time telegrams

• US 10,165,530 B2
• Filed: 03/22/2016
• Issued: 12/25/2018
• Est. Priority Date: 03/22/2016
• Status: Active Grant

• Current Assignee: Christoph Ruland
• Original Assignee: Christoph Ruland
• Inventors: Ruland, Christoph, Schneider, Matthias
• Primary Examiner(s): Nowlin, Eric
• Application Number:
  US15/077,857
• Publication Number:
  US 20170280402A1
• Time in Patent Office: 1,008 Days
• CPC Class Codes: H04W 12/10 Integrity
• CPC Class Codes: H04W 12/61 Time-dependent
• CPC Class Codes: H04W 12/67 Risk-dependent, e.g. selecting a security level depending on risk profiles
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A method is proposed for verification of time data from a time signal modulated on a continuous carrier signal with steps to receive a first time signal with a first reference time, to receive a second time signal with a second reference time, which follows the first reference time in time, for calculation of the target time interval lying between the reference times from the time data contained in the received time signal, to determine a time interval and determine a reference time interval, using counting of periods of the continuous carrier signal within the time interval, for comparison of the target time interval with the reference time interval and to send an error signal, if the deviation determined by the comparison surpasses a stipulated tolerance value.

Claims

1. A method for verification of time information from time data modulated on one or more continuous carrier signals, comprising:

receiving a signal;

receiving, at a first reference time, a first time signal or a first time telegram within the received signal;

receiving, at a second reference time which follows the first reference time in time, a second time signal or a second time telegram which follows the first time signal or the first time telegram in time within the received signal;

calculating a target time interval between the first time signal or the first time telegram and the second time signal or the second time telegram from the time data contained in the received first time signal or the received first time telegram and the received second time signal or the second time telegram, or from received preceding verified time information and the second time signal or the second time telegram;

determining a reference time interval by counting of periods of the received signal within an actual time interval between the first reference time and the second reference time;

performing a comparison of the target time interval with the reference time interval; and

outputting an error signal, if a deviation determined by the comparison surpasses a stipulated tolerance value.

2. The method according to claim 1, wherein, for verification of time information from the target time interval determined from the first time signal or the first time telegram and the second time signal or the second time telegram transmitted in a fixed time grid used for determination of the reference time interval, the method further comprises:

counting periods of the received signal in the actual time interval between the first reference time and the second reference time determined by the first received time signal or the first received time telegram and the second received time signal or the second received time telegram respectively;

determining a deviation between the target time interval and the reference time interval; and

verifying the time information when the deviation is less than or equal to the stipulated tolerance value; and

generating the error signal when the deviation is greater than the tolerance value.

3. The method according to claim 1, wherein the method further comprises:

the time information is comprised in time telegrams transmitted in packet-oriented mode from a loose time grid; and

for determination of the reference time interval, the method includes counting periods of the received signal in the actual time interval between the first reference time and the second reference time determined by the first received time signal or the first time telegram and the second received time signal or the second received time telegram; and

for determination of the reference time interval, the method includes counting periods of the received signal in the time interval between an end of the first received time signal or the first received time telegram and a start of the second received time signal or the second time telegram; and

adding a packet transmission time to the already counted periods.

4. The method according to claim 3, further comprising determining the packet transmission time by counting the periods of the first received time signal or the first time telegram during transmission of a packet, which contains the time telegram.

5. The method according to claim 3, wherein a pre-determined value is added as the packet transmission time.

6. The method according to claim 3, further comprising:

counting the periods for each of a plurality of modulated frequencies of the one or more continuous carrier signals using a separate counter for each; and

weighting the counted periods with period times of the plurality of modulated frequencies of the one or more continuous carrier signals.

7. The method according to claim 3, further comprising establishing variation of a period time of a received frequency-modulated signal of the one or more continuous carrier signals according to data derived from the received frequency-modulated signal by demodulation.

8. The method according to claim 1, further comprising establishing counters for counting the periods during the different states of the applied modulation scheme used for modulation of time data on one or more continuous carriers.

9. A device for providing a remotely synchronized verified time base, the device comprising:

one or more Receiver-Frontends configured to receive a signal including time signals or time telegrams modulated on one or more continuous carrier signals;

one or more Frame-Synchronization Units configured to extract time signals or time telegrams from the received signal and to mark a reference time interval;

one or more Decoders configured to decode time data from the extracted time signal or the extracted time telegram;

one or more Reference-Time-Interval-Measurement Units configured to count periods of the received signal in an actual time interval between a first reference time determined by a first time signal or a first time telegram and a second reference time determined by a second time signal or a second time telegram, the counting of periods of the received signal is controlled by marks of the one or more Frame-Synchronization Units, the one or more Reference-Time-Interval-Measurement Units including a plurality of counters, the one or more Reference-Time-Interval-Measurement Units configured to use different counters of the plurality of counters for different states of a modulation scheme, the counted periods are used to calculate the reference time interval;

one or more Target-Time-Interval-Calculation Units configured to calculate a target time interval lying between time information from time data contained in the received time signals or the received time telegrams that are received correctly;

one or more Time-Interval-Comparison Units configured to perform a comparison of the target time interval with the reference time interval and to send an error signal, if a deviation determined by the comparison exceeds a stipulated tolerance value, and to produce verified time information when the deviation is less than or equal to the stipulated tolerance value;

one or more Control Units configured to forward the verified time information and process error handling when the deviation exceeds the stipulated tolerance value; and

one Time-Synchronization Unit configured to process verified time information output from the one or more control units for evaluation and optimization;

the one time-synchronization unit including an output that is the verified time information delivered to application processes and to the Target-Time-Interval-Calculation Unit.

10. The device according to claim 9, wherein the one or more Receiver-Frontends are designed as tuned radio frequency receivers.

11. The device according to claim 9, wherein the counted periods are periods of a rectified received signal.

12. The device according to claim 9, wherein the device is designed as a billing unit in a charging station, a taximeter, a wind power unit, solar unit or as another unit in which time-dependent actions are conducted and in which correctness of an available time base must be present.

13. The device according to claim 9, wherein the device is designed as a time service calculator, time server, trusted platform module or hardware security module.

14. An electronic control system configured to output a verified actual time, the electronic control system comprising:

a Receiver-Frontend Unit configured to receive a sequence of time signals or time telegrams modulated on a continuous carrier signal, the Receiver-Frontend Unit including a first output for outputting a data sequence, each data sequence containing a demodulated time signal of the sequence of time signals or a demodulated time telegram of the time telegrams and including a second output for outputting the received signal that includes data that is used to count periods of the received signal, the second output can be given in an analog or digital representation;

a Frame-Synchronization Unit coupled to the first output, which extracts the demodulated time signal or the demodulated time telegram from the first output of the Receiver-Frontend Unit and determines a reference time of the time signal or the time telegram;

a Reference-Time-Interval-Measurement Unit coupled to the second output of the Receiver-Frontend Unit, wherein the Frame-Synchronization Unit is coupled to a control input of the Reference-Time-Interval-Measurement Unit, which generates a start control signal upon recognition of a first reference time of a first time signal or a first time telegram in response to which the Reference-Time-Interval Unit starts counting the periods of the received signal, the Frame-Synchronization Unit configured to apply a stop and reset signal upon recognition of a second reference time of a next succeeding valid time signal or a next succeeding valid time telegram in response to which the Reference-Time-Interval-Measurement Unit stops counting the periods of the second output of the Receiver-Frontend Unit, the Reference-Time-Interval-Measurement Unit configured to calculate an actual reference time interval using the counted periods from one or more counters controlled by control signals from the Frame-Synchronization Unit, the counted periods are weighted by a period time of the periods counted by a respective one of the one or more counters, the Reference-Time-Interval-Measurement Unit configured to provide the actual reference time interval signal being representative of the calculated actual reference time interval;

a decoder configured to decode the demodulated time signal or the demodulated time telegram to extract time information;

a Target-Time-Interval-Calculation Unit configured to perform a calculation of a target time interval between first time information from the time information received with the first time signal or the first time telegram and second time information from the time information received with a second time signal or a second time telegram which is the next succeeding valid time signal or a next succeeding valid time telegram, the Target-Time-Interval-Calculation Unit configured to provide a target time interval signal representative of the calculated target time interval to the Time-Interval Comparison Unit and to provide the time information to the Time-Interval Comparison unit representative of the second time information to be used as time information of the first time signal or first time telegram; and

a Time-Interval-Comparison Unit configured to receive the reference time interval signal from the Reference-Time-Interval-Measurement Unit and the target time interval signal from the Target-Time-Interval-Calculation Unit, the Time-Interval-Comparison Unit configured to calculate a difference between the time reference interval and the target time interval and to compare the difference to a threshold value, if the difference is smaller than the threshold value, the time information received from the Target-Time-Interval Calculation Unit is outputted to a Control Unit, and if the difference is greater than or equal to the threshold, an error signal is output to the Control Unit; and

the Control Unit configured to process and to forward the output of the Time-Interval-Comparison Unit and error handling, the Control Unit is configured to receive errors generated from all other units, the Control Unit configured to monitor a sequence of confidence values to detect trials of clock manipulation.

15. The electronic control system of claim 14, wherein the received signal is a modulated signal or a plurality of modulated signals modulated by frequency, amplitude, phase, or a combination thereof, and/or multiplexed by spreading techniques.

16. The electronic control system of claim 14, wherein the received signal contains the sequence of time signals or the time telegrams, the received signal including at least one of a space-based global positioning signal (GPS), a time signal radio station based signal, a radio ripple control based signal, a wired ripple control based signal, and a terrestrially-based enhanced long-range navigation signal.

17. The electronic control system of claim 14, being adapted for parallel processing of a plurality of the sequence of time signals or the time telegrams modulated on the carrier signals received concurrently to obtain a set of target-time intervals, reference-time intervals and respective verified time information and confidence signals, and further comprising a Time-Synchronization Unit for receiving the set of verified time information and confidence signals for processing in order to generate a resultant verified time information that is used for synchronizing the time base.

18. The electronic control system of claim 17, the Time-Synchronization Unit being configured to calculate a resulting value for the set of verified time information for which a confidence signal is present to provide the verified time information which is output to application processes and fed back to the Target-Time-Interval-Calculation Unit.

19. The electronic control system of claim 14, being coupled to one of a billing unit in a charging station, a taximeter, a wind power unit, a solar unit, and an actuator.

20. The electronic control system of claim 14, comprising a hybrid analogue-digital integrated circuit chip implementing the Receiver-Frontend, the Frame-Synchronization Unit, the Reference-Time-Interval-Measurement Unit, the Decoder, the Target-Time-Interval-Calculation Unit the Time-Interval-Comparison Unit and the Control Unit.