Time and frequency calibration via GPS

For calibration of more accurate time and frequency standards, we offer on-site calibration using the GPS satellite system as an intermediate reference. This requires installation of equipment for reception and storage of data from the GPS.

The method, known as GPS Common View, is similar to that used by RISE to provide international traceability.

We can also verify and calibrate the time synchronising and positioning performance of different types of GPS and GLONASS receivers. 

On-site calibration using GPS

The method involves calibrating a frequency standard or clock (DUT) against UTC(SP) by means of simultaneous measurements of GPS satellite signals by both the customer and by RISE.  The use of common satellites eliminates many of the common measurement errors.  In addition, the changes that are observed in the time intervals [UTC(SP) – DUT] provide an estimate of the DUT frequency relative to UTC(SP).

Automatic calculation

The measured values registered by the customer can be transferred automatically to RISE over the Internet.  Performance calculation is performed automatically by RISE with the results being sent to the customer by (for example) e-mail.  How often this is done is agreed with the customer, but can in principle be done on a daily basis.  The accuracy of frequency measurement, averaged over a day, is better than ±1E-13, but does depend on the quality of DUT.


All instrumentation needed (GPS receiver, time interval counter and computer) can be supplied by RISE.

TWSTFT - Two-Way Satellite Time and Frequency Transfer

TWSTFT is a technique that utilizes commercial geostationary satellites for time and frequency transfer. The technique is active in contrast to GPS, that is, time signals are transferred between laboratories via satellite transponders. Read more...


SP has equipment for GNSS (Global Navigation Satellite Systems) for applications in Time and Frequency, Positioning and Atmospheric Studies.Read more...


SP develops new methods for the determination of position, velocity, and acceleration, which both provides better accuracy and the possibility for the use of GPS in environments where it has not previously worked. Read more...

Related Information




GNSS - Global Navigation Satellite Systems

Business Areas

RISE Safety and Transport

Contact Persons

Kenneth Jaldehag

Phone: +46 10 516 54 08

Carsten Rieck

Phone: +46 10 516 54 40

RISE Research Institutes of Sweden, Phone 010-516 50 00, E-mail info@ri.se

The RISE institutes SP, Innventia and Swedish ICT have merged in order to become a stronger research and innovation partner for businesses and society.
During 2017 sp.se will be one of several websites within RISE. Please visit ri.se for more information about RISE.