Measuring-instrument remote-calibration system and measuring-instrument remote-calibration method

• US 7,130,752 B2
• Filed: 10/31/2003
• Issued: 10/31/2006
• Est. Priority Date: 04/28/2003
• Status: Active Grant

• Current Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Original Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Inventors: Yoshida, Haruo, Arai, Masaru, Hino, Yoshio, Matsumoto, Hirokazu, Nakazawa, Masataka
• Primary Examiner(s): Bui, Bryan
• Assistant Examiner(s): Le, Toan M.
• Application Number:
  US10/697,321
• Publication Number:
  US 20040215412A1
• Time in Patent Office: 1,096 Days
• Field of Search: 702/85, 455/130, 455/63.3, 455/67.13, 73/10.1, 73/10.3
• US Class Current: 702/85
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00

Abstract

In a measuring-instrument remote-calibration system and measuring-instrument remote-calibration method, a measuring standard quantity is converted into a parameter adapted for communication, or based on measuring standard quantity, a parameter adapted for communication is generated and sent to a remote place. Alternatively, when the measuring standard quantity is not suitable for communication, it is converted into a form adapted for transportation and the converted measuring standard quantity is sent to a remote place. After the converted measuring standard quantity reaches the place, it is restored to the original measuring standard quantity, thus enabling calibration. The result of the calibration is certified.

Claims

1. A measuring-instrument remote-calibration system for remotely calibrating a measuring instrument, comprising:

converting means for converting a physical standard used as a measuring reference into a transmission signal and for transmitting the signal through a first communication medium; and

calibrating means for receiving and restoring the transmission signal to the measuring reference, and for performing calibration on the measuring instrument based on the measuring reference,

wherein the converting means is located at a standard authority, the calibrating means is located at a remote location, and the standard authority provides certification of the calibration.

2. A measuring-instrument remote-calibration system according to claim 1, wherein results of the calibration are sent from the remote location to the standard authority via a second communication medium.

3. A measuring-instrument remote-calibration system according to claim 2, wherein the first and second communication mediums are the same.

4. A measuring-instrument remote-calibration system according to claim 2, wherein the first and second communication mediums are different.

5. A measuring-instrument remote-calibration system according to claim 1, wherein:

the converting means comprises a converting unit and a communication unit located at a standard authority; and

the calibrating means comprises a reception unit and a calibration unit located at a remote location.

6. A measuring-instrument remote-calibration system according to claim 1, wherein the standard authority is the highest national calibration authority.

7. A measuring-instrument remote-calibration system according to claim 1, wherein the remote location is located overseas, relative to the standard authority.

8. A measuring-instrument remote-calibration system according to claim 1, wherein the physical standard is related to frequency information.

9. A measuring-instrument remote-calibration system for remotely calibrating a measuring instrument, comprising:

converting means for converting a physical standard used as a measuring reference into a transmission signal and for transmitting the signal through a first communication medium;

calibrating means for receiving and restoring the transmission signal to the measuring reference, and for performing calibration on the measuring instrument based on the measuring reference,

wherein the standard authority performs the certification in accordance with the result of precise measurement involving uncertainty evaluation based on the calibration.

10. A measuring-instrument remote-calibration system according to claim 9, wherein the physical standard is related to frequency information.

11. A measuring-instrument remote-calibration system for remotely calibrating a measuring instrument, comprising:

converting means for converting a physical standard used as a measuring reference into a transmission signal and for transmitting the signal through a first communication medium;

calibrating means for receiving and restoring the transmission signal to the measuring reference, and for performing calibration on the measuring instrument based on the measuring reference; and

a remote calibrating network for linking the standard authority and the remote place,

wherein a confirmation of the calibration operation and a confirmation of the precision of the standard are performed by mutually monitoring identical standards retained by a plurality of authorities linked to said remote calibrating network.

12. A measuring-instrument remote-calibration system according to claim 11, wherein the physical standard is related to frequency information.

13. A measuring instrument remote calibration method comprising the steps of:

converting a physical standard used as a measuring reference into a transmission signal;

transmitting the transmission signal by a communication means;

receiving the transmission signal;

restoring the measuring reference from the transmission signal; and

performing calibration based on the measuring reference;

performing certification, in accordance with results of the calibration, wherein;

the steps of converting a physical standard and performing certification are performed at a standard authority; and

the steps of restoring the measuring reference and performing calibration are performed at a remote location.

14. A measuring instrument remote calibration method according to claim 13, further comprising transmitting results of the calibration from the remote location to the standard authority;

and transmitting a certification certificate from the standard authority to the remote location.

15. A measuring instrument remote calibration method according to claim 13, wherein the steps of transmitting the transmission signal, transmitting results of the calibration, and transmitting a certification certificate are all performed within a single type of communication medium.

16. A measuring instrument remote calibration method according to claim 13, wherein the steps of transmitting the transmission signal, transmitting results of the calibration, and transmitting a certification certificate are performed within various types of communication mediums.

17. A measuring instrument remote calibration method according to claim 13, wherein the standard authority is the highest national calibration authority.

18. A measuring instrument remote calibration method according to claim 13, wherein the remote location is located overseas, relative to the standard authority.

19. A measuring instrument remote calibration method according to claim 13, wherein the step of performing certification is accomplished in accordance with the result of precise measurement involving uncertainty evaluation based on the step of performing calibration.

20. A measuring-instrument remote-calibration method according to claim 13 wherein:

the standard authority stores highly accurate standards;

the measuring reference is frequency based; and

the certification result is transmitted from the standard authority to the remote location by a communication medium.

21. A measuring instrument remote calibration method according to claim 20, wherein the standard authority and the remote location:

are positioned so that a satellite is simultaneously observed; and

perform frequency calibration by utilizing a signal transmitted from a signal source in the satellite.

22. A measuring instrument remote calibration method according to claim 20, wherein the standard authority and the remote location:

are positioned so that a satellite is simultaneously observed; and

the frequency standard is restored at the remote location by comparing a reference clock signal included in a signal source in the satellite and a frequency-divided signal from a frequency-controllable oscillator, and feeding back the frequency-divided signal to the frequency-controllable oscillator so that an error signal between both signals is zero.

23. A measuring-instrument remote-calibration method according to claim 20, wherein, in the step of restoring the measuring reference, a physical quantity directly linked to the frequency is restored by physical law at the remote location.

24. A measuring-instrument remote-calibration method according to claim 20, wherein, in the step of restoring the measuring reference, the restored frequency standard is converted into a voltage standard, and based on the restored voltage standard, a physical quantity converted into a voltage is remote-calibrated.

25. A measuring-instrument remote-calibration method according to claim 21, wherein the satellite is one of a global positioning system satellite and a quasi-zenith satellite.

26. A measuring-instrument remote-calibration method according claim 21, wherein reception of a plurality of pieces of frequency information from the satellite minimizes an error based on a radio wave propagation delay time caused by dielectric material including a cloud or water vapor positioned between a receiver on the ground and a radio wave transmitter provided in the satellite in a state in which the satellite is over the receiver.

27. A measuring-instrument remote-calibration method according to claim 22, wherein the satellite is one of a global positioning system satellite and a quasi-zenith satellite.

28. A measuring-instrument remote-calibration method according to claim 22, wherein reception of a plurality of pieces of frequency information from the satellite minimizes an error based on a radio wave propagation delay time caused by dielectric material including a cloud or water vapor positioned between a receiver on the ground and a radio wave transmitter provided in the satellite in a state in which the satellite is over the receiver.

29. A measuring-instrument remote-calibration method according to claim 23, wherein a Josephson voltage is used as the quantity directly linked to the frequency.

30. A measuring instrument remote calibration method comprising:

converting a physical standard used as a measuring reference into a transmission signal;

transmitting the transmission signal by a communication means;

receiving the transmission signal;

restoring the measuring reference from the transmission signal;

performing calibration based on the measuring reference; and

confirming the precision of the calibration by performing mutual monitoring of identical standards retained by a plurality of standard authorities linked to a remote calibrating network.

31. A measuring-instrument remote-calibration method according to claim 30 wherein, in the step of performing the mutual monitoring, the mutual monitoring is performed between standard authorities nationally and internationally.

32. A measuring-instrument remote-calibration method, comprising:

generating a physical standard in a standard authority that stores highly accurate standards by using a physical standard generating means integrated with an optical communication path;

transmitting the physical standard by the optical communication path to a calibrated authority at the remote place in which calibration is performed;

performing calibration by restoring the transmitted physical standard in the calibrated authority; and

transmitting a certification result, in accordance with the result of the calibration, from the authority to the calibrated authority by the communication means.

33. A measuring-instrument remote-calibration method according to claim 32, wherein:

the standard authority is a higher-level-standard authority, and an interference signal, caused by a physical quantity used as a reference in the higher-level-standard authority, is transmitted by an optical communication path to a calibrated authority at the remote place in which calibration is performed;

calibration is performed by restoring the transmitted interference signal to a measuring standard in the calibrated authority; and

in accordance with the result of the calibration, a certification result is transmitted from the higher-level-standard authority to the calibrated authority by the communication means.